2020

MSBTE

TYDiploma

Scheme

Strictly as per new revised T' Scheme

w.e.f. academic year 2019-2020

AUTOMOBILE ENGINEERING
Semester VI Mechanical Engineering Group (ME) (Code 22656)

New Publication
Same Subject, Same Author with
S. D. Ambatkar
Includes:
Papers as per Bloom's Revised Taxonomy.
Model QuestionMSBTE Question Papers upto Summer
2019
Solved Latest
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Publications

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 Automobile Engineerin9
(Code:22656)

THIRD YEAR DIPLOMA

Maharashtra State Board of Technical Education (MSETE)

Semester VI - Mechanical Engineering Group (ME)

Sturictly as per new revised Scheme w.e.f.academic year 2019-2020

S. D. Ambatkar
ME HeatPower), BE (Mechanical)
dge
Scnior Lecturer in ATSSMS Poly.

nov
(Al Tndia Shri Shivaji Memorial Society's Polytechnic)
Pune 411001

MDEDA Prce t 195/

TechTechKnowledge
Public ations

Bok Code MDE9A))

 NAutormobie Engineering (MSBTE Sem-V) Table of Contents

UNIT 132 Ficions da Chassis, Frarne and BoG). 1-18

Chpter 1 Introduction to Automobile 1-1 to 1-36 Requirerments of Chassis, Frame and Pody-1-19

14.1 Laad on Chassis Frane 1-20

Sylabus:
1.4.2 Types of Frame Corstrucãon 1-20
a Automoble: Desniaon, Cassficadon of Automobžes, Major
.

Corponents. of Automobdes with her Fincon and 1.5 Sub-Frame-- 1-23

Locaton 15.1 Basic Body Nomenclahre 1-24

12 Vehicde Layout Defnidan Sgrticance of Vehicde Layout,

Significance of Body Seaming
Dillerent ypes of Veticke layouts (FEFWD, FERwD,
REFWD 4WD), Achvantages, Disadventages, Appfications| 1.7 Need and Importance of Aerodynamics aspect. 1-25

nd Comperisorns of Diferent types of vehicde layours

Altemative Fuel. 1-28
13 Rinction of Chassis, Frame and Body: Requirement of
Chessis, Freme and Body, Load acting on Frame, 1.8.1 Introduction 1-28
Cassiicabon of Chassis Frames with advartages,
1.82 Need. 1-29
sadvantages and eppicatons (Corvedianal, Unitized ****** ****

Body, Sub Freme), Basic Body Nomencdature. 1.8.3 Fuel characterisics of CNG and LPG. mt******* ******** 1-29

14 Slnlicance of Body Streamlining: Need and Importance

1.84 Tte CNG Engine ******************** m*m******* 1-30
d aerodynamic Aspecs, Basic tems relaied with Car
Aerodynamics ( e.g. Drag, Lit, Sin Fricton, Fom Drag. 1.8.5 Liquid Petroleum Gas ( LPG ).. 1-30
Wake, Coetficient of Drag
1.9 Electric Vehides.. 1-32
15 Alternative Fuels: LPG and CNG: leed, Fuel
1.9.1 introducton** *e******** 1-32
Characte ristics, Constructon and Working, Advantages,
Limitations; Layout of. Electic Vehicles: Need, Working 1.9.2 Need *****************************************e *on************ 1-32
Advantages, Limitations. Hydrogen as tuel
1.93 Working of Electic Vehicles.********************* ****** 133
Introduction to Automobile 1-1
1.9.4 Advantages of Electric Vehicdes. 34

1.11 Classification of Automobiles ******* 1-2 1.9.5 Disadvantages of Electric Vehicles.

onoeruosnec*******e 34

19.6 Limitations of Electric Vehicles.

112 Major Componerts of Automobile with 35

Their Functon and Lócation.-* ***** 14 1.10 Hyd-ogen Fue! Cel..

12 Vehicde Layout 1-8

121 Significance of Vehicle Layout 1-8

122 Types of Vehicle Layout 1-9

123 Diferentiate between Front and

Rear Mount Engine Vehicle. nmmnomnaoaaon 1-16

124 Articulated Vehicles. ***

**** *******1-163

12.5 .Heavy Commercial Vehicles *********************** -J6

12.6 Rigid Vehicles-- 1-17

1.3 Chassis, Frame and Body.- 1-17

1.3.1
Frame Construction.
I*********** ******" ************ 1-18
 AP

1)Introduction to Automobile
Unit-
Syllabus:
Definition, Classification of Automobiles, Major Components of
Automobiles with their Function
,Adomobile:
and Location.
Significance of Vehicle Layout, Different types of Vehicle layouts (FEFWD, FERWD,
Vehicle Layout: Definition
12
RERWD, 4WD), Advantages, Disadvantages, Applications and Cormparisons.of Diferent types of vehicle

layouts.
Frame,
1.3 Function of Chassis, Frame and
Body Requirement of Chassis, Frame and Body, Load acting on
(Conventional, Unitized
Classification of Chassis Frames with advantages, disadvantages and applications

Body, Sub Frame). Basic Bady Nomenclature.

related with
1.4 Significance of Body Streamlining: Need and importance of aerodynarmic Aspects, Basic tems
Car Aerodynamics. (eg. Drag, Lit, Skin Friction, Form Drag, Wake, Coeficient of Drag)

1.5 Alternative Fuels: LPG and CNG: Need, Fuel Characteristics, Construction and Working, Advantages,
Limitations; Layout of Electric Vehicles: Need, Working. Advantages, Limitations. Hydrogen as fuel

1.1 Introduction to Automobile

Present age is called the age of "Automobile"' or self propelled vehicle. A vehicle producing power within itself for its
propulsion is known as self propelled vehicle e.g. moped, scooter, motorcycle, etc. Germany is the birth place of
automobile
as
The automobile is define a self propelled vehicle which will be run on the ground.
The firsi automobile
powered by steam engine as
built in France by Nicholas-Joseph Cugnot in 1769-70. It was a
three wheel vehícle having speed 2% miles/hour.
Olfver Evans in 1805, operated his Evans Amphibian for the first time in Philadelphia, America. This vehicie was
designed with four wheels and the body was in the forn of a flat boat. Two.outstanding successes in America were the
Stanley Steamer and the White Steam Car, introduced in 1895 and 1902 respectively. Both of these automobiles gave
excellent perförmance. The Stanley Steamer is credited with being the first self- propelled vehicle to attain a road speed
af 160 kmper hour.
The development of an internal combustion engine for antomobile was accelerated the change in the production of
vehicle. The first practical automobile fitted with I.C. engine which ran on city gas and was ignited by
clectric spark
plug by Belgium iventor Eienme Lenor in 1860. Inl 866 Nikofaus A. Otto and
Engen Langen of Germany, invented'a
four stroke engine which was, the predecessor of modem gasoline engine. again modificd by Gottlicb Daimler
It was
who substituted oil for gas. Gottlieb Daimler presented high speed LC. engine which revolutionized
a automotive
transportatio.

In 1896-97 Germany, France, England, America. considerable

work was carried for the development of gasoline
utomobiles and until 1910, the automobile was in the experimental
stage.
By the improvement in the roads, rapidity and economy
of motor transportation and the First World War were the main
factors which lead to the frther development automobile.
of an

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 Automobile Engineering (MSBTE Sem-V) 1-2 Introductionto Automobiles

we
The rapid industialization and development of an automobile gave birth for the growth. In India the first
imported inl898 and it is continue for about 50 years.
motor .car
Visveswaraya
Sir M. an made establishment of an automobile
industry in 1935.
The first automobile industry in India, Hindustan Motor Limited Kolkata, came in the
at year 1947and then Premier
Automobile Limited at Mumbai, in 1948. Initialy they manufacture
cars. Today there are lot of industries developed.
The govemment's liberalization policy and the transformation
of Indian economy from a protected one to a highly
competitive one has offered an unpredicted future of the Indian
Automobile Industries. The industry is certainly headine
for a tremendous growth, the number of anmual, sale of car and
jeep at domestic front is expected. The demand
raising at an average of 25%, compared to the previous is
coresponding period.
Indian automobile industry taking big leaps forward on fronts
3 in preparation for entering 21" century. These are
:
1 The technology gaps are being bridged not only between
India and the world but also between the
future. Almost every compay introducing present and the
a new engine which is smaller, powerful and lighter and more efficient.
2. The vehicle owners and users havea greater
choice of vehicles. So manufacturing company
needs and developing new models introducing look at the customer
new features.
3. Tbe vehicle manufacturers
are concentrating on their plant and the manufacturing
process is changing,with a view
to provde geater economy and eficiency
in production and better reliability, endurance and performance
vehicle. in

1.1:1 Classification of Automobiles:

MSBTE:W14 S:15,W15S-16,W-16,
W-17, S-18,S-19
te vanoustypes of automobile badie
(W-14,W-15W-17)
afeclassiication.ofautomobile
S15,S18,$19)
Cassify automobiles.
aHow Automobiles.areclassied S-16
The automobiles are classified W16)
as follows:

Classification of Automobiles

(a) According to use

b) According to capacity

c) According to fuel
used

0) According to wheels

(e) According to drive

(1) According
to transmission

o) According to suspension
system

h) According to engine fitting

)
Accarding to body construction

Fig.C1.1

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 Engineering (MSBTE Sem-V) 1-3 Introduction to Automobiles
Automobile

(a) According to use

Passenger Cars ) Goods Carriage

)
Special Purpose iv) Earth Moving
(i)
(v) Motor Cycle (Bikes) (vi Mopeds

(b) According to capacity

)Heavy transport vehicle eg. Trucks and buses.

Light transport vehicle e,g. Car,jep, minibus, matador.
(c) According to fuel used

)Petrol vehicle: Motor cycle, scooter etc.

() Diesel vehicle: Buses, trucks.

(i) Gas vehicle: Buses.

v)Solar vehicle Storage battery types.
(d) According to wheels

Two wheeler :eg. Scooter,motorcycle.

) Three whecler : e.g. Auto-rickshaw, tempo.
) Four wheeler: e.g. Car,jeep, tractor.

iv) Sixwheeler: Truck, buses.

e Accordingto drive

According to sitting(driver) arañgement:

(a) Left hand drive e-g. American
vehicle, oldIndian wehicles.
6)Righthand driveeg. Indian vehicle.
) Whetherthefront axle,rear axde or
bothaxle drive :
a) Eront wheel drive eg. Manuti Car
b) Rearwheel.drivee.g.Ambassador, premier.
(All wheel driveeg. Joep.
40According totransmission

) Coventional in which ordinary

crash type gear box
is usede.g All Indian car.
n) Semi-atomatic having two
pedal transmission
clutch control
using manual operation with standard gear
box and antomaic
üi) Fully automatic.
(g) According to suspension
system
Conventional (Rigid): Leaf
spring.
) Independent : Hydraulic
shock absorber.

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 Introduction to Automob
Engineering (MSBTE Sem-VI) 1-4
Automobile

(h) According to engine fitting

)Front engine.
(i) Rear engine.

(ii) Transverse under floor engine.

According to body construction

0
A. Passenger Cars

a) Sedan/Saloon b) Hardtop

c)Lit
e)Coupe
gConvertible
back (Hatchback)

.
d) Station Wagon

Limousine

h Estate Car
B. Heavy Vehicles/Trucks

a Tuck Punjab Body

b Truck Half Body
Truck Platform.Typa
dTruckith Trailer
e Dumpet Tanker

Car Jeep Pickup

O
Straight truck
Half body truck Platformtruck

Delivery van
Fanker.
Dumper trucks .

Station wagon
Bus
Trailer
Fig. 1.11:Types of automobile
1.1.2 Major Components bodies
of Automobile with
Their Function
and Location:
NNamemajor componentprautomooieand
MSBTE : W-14.W-11 S-18
state tne runcion any
QNameany sour majorcomponents of tourcomponents.
O
of automobile
and stäte theirfuncion W-1
Whatarethe
majorcomponents mountedd
on venicle
chassis State purpose
the of.eachcoponent $-1

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 Automobile Engineering (MSBTE Sem-V)
1-5 Introduction to Automobiles

An automoble is consist of substructure called chassis and superstructure as body.

Chassis is a main structure upon which all the major component or an automobile which are necessary
to propel the
vehicle are assembled.

Chassis comprises of everything of a vehicle except the body, cabin and equipment. The automobile
chasis consist of
following components.

Components of chassis

(1) Frame

(2) Engine

(3) Transmission system

(4) Suspension system

(a) Conventional system

H Independent systemn

(5) Controls

Ha) Steering system

6) Brake systern

c) Engine control .

(6)Electrica controks

Radiator
Fig: C1.2
) Frame
The frame is the main part
of the chassis on which Temaining parts
extremely rigid and strong so that of chassis àre mounted. The frame should be
if can withstand shocks, twists, stresses
vehicle is moving on road. Itis also and vibratons to which it is subjected while
called underbody.
The frame is supportedon the whecls
and tyre assemblies.
radius to front wheels. widens The frame is narrow the
It out at the rear sidé to provide in front for providing short furning
larger space in the body.
Ttis a skeleton to hold the major
unittogether. These
are of two types:
(a) The conventional pressed
steel frame to which
all mechanical
unit are attached.
(6) Integra or frameless
construction in which
body construction
decreases the weight perfom combine function of body and irame. So it
and save fuel consumption
damage occur during also reduces manufacturing
accident. cost.but. increases repair f

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 Introduction to Automobiles
EAutomobile Engineering (MSBTE Sem-V) 1-6

Comparison of conventional chassis framed and frameless type chassis framed:

MSBTE: W1

med and frameless vehicle

W15

SE No
ramed yehich rameless velhicle
All mechaical units are attached to Performed combine function body and frame.

perforn function of only support (Frame).

side members
2. Longitudinal member and cross member Floor is strengthened but cross member and heavy

form the frame. are eliminated from body, which are welded together.

3. Heavy in weight used for truck and Buses. Light in weight used for small cars.

4. More fuel consumption. Less fuel consumption.

Manufacturing cost is more. Manifacturing cost is less.

6. Repair cost less due to higher impact Repair cost more due to lower impact resistance.
tesistance.

Stronger and Heavy construction. Results in a light but stiff construction.

Frame and Body are not integral structure. Frame and Body are integral structure for extra strength and
durability
9 Frane is up swept at rear and front to In sorme cases the sub frames are also used along with this type
accumulate movement of the axle.
of construction.
Eg. Tata, Ashok Leyland vehicles. Eg. Small and medium cars, small buses

10. During collision the body transfers the | During collisíon the body-crumbles,
thereby absorbíng the
shock due to impact and thus not safety to shock. duc to impact and
thus providing safety to t
the passengers. passengers.

11. Topless cars are simple to design. Topless carS are diticult to design.

(2) Engine

It is the powerhouse which develop and provides motive power to propelled

the vehicle for performing the vam
function of vehicle. It is located at the front,rear or in middle depending
on the type ofapplication of layout.
(3) Transmission system:

W-16
MSBTE: W-15,
OState functions of transmisslon system in automobile.

Write functions ofynyersatjointang sipjoint 16)

This system consists of clutch, gear box, universal
joint, propeller shaft, differential,
rear axle, wheel.
Functions:

(a). Clutch is used to connect or disconnect engineu

the engine power to road wheel
when desire. It is located an
the Transmission system.

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 Automobile Engineering (MSBTE Sem-VI) 1-7 Introduction to Automobiles

(b) Gearbor is used to obtain the various fixed torque ratio according to requirement. It also help to reverse ne
vehicle.

)Universal joint and propeller shaft: It is located between gear box and diíferential. It transmit the torqgu
from the gear box shaft to the final drive and also adjust the different inclination when vehicle come across a bunmp
or shock.

(d) Differential : It is located in the rear or front axle depending upon type of drive. It helps to tun the vehicie
through right angle and split the torque in equal proportion to the road wheel.

It is a weight carying portion whether it may be front or

rear loaded at intermediate point. It takes vertical
()Axle:
load due to weight of body, shock load during braking or driving, a torquë reaction due to driving and braking and

a side thrust during cornering.

cope with the
(9 Wheel and tyre : The wheels along with tyre has to take vehicle load, provide cushioning effect and
steering control.

(4) Suspension system

pitching. E
This system isolates the vehicle body from the road shock which are in the form of rolling, bouncing and
provides comfort to passenger and reduce the stress in frame. These are of two types

housing
(a) Conventional (Rigid) system: In which the leaf springs are attached to the rigid beam axle or to axle

(b)Independent system: Here no rigid axle beam and cach wheel is free to move vertically without any reaction on

theotherwheel.
(5). Controls

Vehicle inchudes steering system, braking system and engine

contro.

Steering system lt is used to change the direction of motion of the vehicle by turning the front wheet. The front
(a
driver.
wheels are linked to steering wheel which is operated by the
system
)Brake Ihis system provide safety to the vehidle by stoping quickly or slow dowin while going dowa
vehicle.
slope. The brakes are mounted on all the wheels of a
.

Enginè control :This control réfer to variation in the revolution of the engine shaft in accordance with demand of

fuel supply and accelerator pedal.

This system consist of following:

a) Supply system: Battery and dynamometer.

(b) The starting relay.

(0)Theignition system:Batery or magneto-ignition system.

() Other miscellancous system like driving light, signaling, reverse light, panel ight, wiper etc.

7). Radiator
It is a device used to re-cool the hot engine cooling water for recirculation purpose. The radiator is connected to engine
by hose pipe to allow the cooled water circnlation. It is located at the front or rear depending upon chassis
layout.

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Automobile Engineering (MSBTE Sem-VI) Introductionto Automobiles
1-8

Transmission
Diferential
Distributor -Universal
joint
Frame

Waler pump r Propeller

Engine Sfhaft
Frot CReer
Radiator

Gear box Steering Wheet and tyre

wheel

Fig. 11.2: Layout of chassis frame and its maîn component

8) Body (superstructure)

Vehicle body is a superstructure. Body is either integral with the under

frame or bolted to the frame. The body and
chassis make complete vehicle.

A body consist of a doors, windows, engine cover,

roof, luggage, cover etc. Different type of body is attached to chassis
according to application.

The folowing conditions must be full filled by vehicle

body:
() Itmust be lighter.
6) If must have réasonable fatigue life.

()Should nothave too mnany and complicated components.

d) Must ensure a quite side and easy
entry and exit.
)II must withstand uniform induced
stresses.

1.2 Vehicle Layout

DeinitioH
:1is detined asthe location and arraingementof
lhemain coMpONent suchas
engnëand drve
It can be divided into thre categories
as Front whecl drive, Rear wheel
drive and four wheel
1.2.1 Significance of Vehicle dive.
Layout:
Normally automobile
manufacturers
overall best weight distribution
ted to make their vehicle have
an equal weight distribution
helps the car for
good at acceleration,
for each wheer
important role in weight
distribution.
braking and aya
steering. The different layoutspuay

It also help for handling characteristics

of vehicle. It also concentrates
the drive component
on one area
Enlist various types
of vehicle layauts. MSBTE:S15

S-15
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 Automobile Engineering (MSBTE Sem-V) 1-9 Introduction to Automobiles

1.2.2 Types of Vehicle Layout:

drive used are rear engine rear whel drive, front engine rear wheel drive, front engine
The vehicle based upon type of
drive which are discussed below:
front wheel drive and four wheel

Types of Automobile according

to Drive

1.FrontEngine Rear Wheel Drive

2 Front Engine Front Wheel Drive

3. Rear Engine Rear Wheel Drive

Drive
4.Mid-Engine, Rear Wheel
5FOur.Wheel Drive.

HBRear engine, alf wheel drive (4WD

() Front engine, al wheel dive (4WD

Fig.C1.3:Types of Automobile according to Drive

1. Front Engine Rear Wheel Drive (FERWD)

MSBTE W.15 S 16, S-17.W-17,W-18
w15.S-17,W.18
QWrte advantages of front engine and rear wieldrive
any four

Expain rear wieerdrive vehicle with iont and rear engihe S

disadvantag
16
QSketch and explain rear wheeldrive
chiassis layout of trontengine
the rear, a
Rear-vwheel drive places the engine in the front of thé vehicle and the driven wheels are located at
configuration known as front-engine, rear-wheel drive layout.
axle supported on leaf springs
In this layout a front mounted engine-clutch-gear box unit drives a beam type rear
through apropeller shaft with two universaljoints.
With tlie help coil springs,the front wheels are independently sprung, As shown în Fig. I.5.1,
this layout is one of the
of
oldest layout which remains unchanged for many years.:

Advantages:

Some of the advantages provided by this.system are:

dlin
good Banag
(a) Even weight distribution: Balanced weight distribution between the front and the rear wbeels providing
characteristics.
ches.
0) For easy front wheel stering movement engine occupies the reduod width between the wheel
C)Large luggage space is provided behind the rear seat.
(0) Maintcenace and accessibifity of engine, grar box is easy
and the control overtie acelerator,
cluten,

e)Radiator cvoling is natural (by air) so decreases

the power require for cooling

TedhKanaled
P1D1ieatie0

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 Automobile Engineering (MSBTE Sem-VI)
1-10 Introductionto Automobiles
) Better braking efficiency: The more even weight distribution helps prevent lockup
fom wheels becoming unloaded
under heavy braking.

Luggage spa0

Sleering"

Propeler sheft

Clutch
Enghe Gear box

Rear arle

Difererntial

Radiator

Col spring
Unlversal joint
Leaf sping

Fig. 1.21:Front Engine Rear Wheel

Drive
Disadvantages
. Reduces back seats leg room space.

2. A tunnel is needed for the propeller shaft.

3. Reduces bootspace.

4. Heavier and more expensive.

5. If stuck in mud or snow it is harder to drive away than in

a front wheel drive car.
2. Front Engine Front Wheel Drive (FEFWD)

a neat sketch of front engine frontwheel type MSBTE:W.16,S-17

aDraw yehicle layoiut and label it
(W-16)
QDraW generatayout of front engine front wreel dirive car. RKA i S-10
Engine, clutch, gearbox and final drive build together to form
a single integral assembly. Normally transversal engne
arrangement is used. Longitudinal-mounted engine is the other
possible layout. Weight
distribution tends to be moe
in
than 50% the front axle.

.In this arrangement the engine is fitted in the front of vehicle and drive is given
to the front wheel
.
The propeller shaft length is reduced or neglects the propeller shaft.

The drive is transferred from engine, situated at front end, to the gear box to the differential
with the help of geat dnive
The differential unit is placed in the front axle.

Y NIatig

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 (MSBTE Sem-VI) 1-11 Introduction to Automobiles
Automobile Engineering
Engine- f Final drve

Torque
Converter
Transaxle

Fig.1.2.2 Front Engine Front Wheel Dive

This arangement provides good grip with road

surface due to engine weight at the front.

Absence of propcller shaft can decrease the chassis

height.

propeller shaft in moderm vehicles, but there is

Note that for front engine, front wheel drive vehicle there generally no
is
on each side connecting whecls vith balk joints.
a transaxle with two half shafts laxles

Advantages
Having engine, cutch, gearbox and final-drive in the front makes the front heavy and this helps acceleration (f
compared with a rear engine, front wheel drive which does not exist).

This type of arrangement provides optimum passenger space and a ilat floor line resulting in a transverse under-floor
longitudinal engine position.

The propeller siaft length is recuced oir neglects the propeller shaft
to
Good gipwith road surface duer engine wcight at front
The chance of wtecl skiding and sliping is very much roducod.
Natural air-cooling of the radiator due to motion of vehicle.
it provide "under-steer
Power required for ihe cooling is reduced. When the vehicle is to be 'steer in' to the curve,
characteristics, which always is preferred. .

than over
More passenger room since the propeller shaft is eliminated. Tend to under-steer, which makes them safer
is the
steer (supposing an average driver and no traction-stability .control, under-steer is easier to notice and correct). It
cheapest, lightest and more compact'arangement.
Disadvantages

Traction is penalized when hill-climbing, weight moves backwards.

wheels to brake
Not efficient braking, when braking hardis casy to block the back wheels, it is like only having two
wilth, even though these have a lat of grip duc-to weight transfer to the front:
(accelerate, brake,
Steering radius is redaced because of drive shafts. The front wheels have to do almost all the work
steering).
Application of this layout

The vast majority of car manufäcturers, to say some examples: Ford, Audi, Seat, VW, 10yo1a.

undcr-steer characteristics, which is always prefered.

Justhy Most of the miodern.cars are front wheël drive

in a transverse unEO
* O aTangement provides optimum passenger space and a flat floor line resulting
longitudinal engine position.

The propeller shaft length

is reduced or neglects the propeller shat.
Good gip with road surface due to engine weight at front.
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 Automobile Engineering (MSBTE Sem-V) Introductionto Automobiles
1-12

The chance of whcel skidäing and slipping is very much reduced.

.Natural air-cooling of the radiator due to tnotion of vehicle.

Difference between Rear Wheel Drive and Front Wheel Drive

MSBTES19

frontrearwheeldrive withfront engineffont whieeldrive2

Compare front enginé e 19
SHNoFront Engine ront Whecf Drive WD);
Front Engine Rear WheetDrincRWD
FWD vehicles are propelled viz the front}RWD vehicles are propelled viathe rear wheels
wheels.

2 Ahe propeller shaft dength is reduced or Require longer propeller shaft-length.

negicts the propeller shaft.
3 FWD vehicles ofen havc more interior space RWD vehicles often have less interior space.compared
compared to RWD vehicles. FWD vehiles.
FWD vehicles are less balanced. RWD vehicles are more balanced.
5 FWD vehicles allow for less control. RWD vehicles allow for better controf.
6 FWD vehicles cannot be able to drift
RWD vehicles are able to drift, while FWD vehicles cammot
When the vehicle is to be 'steer in' to the For easy front whee steering movement engine occupies the
Curve, it provide 'under-steer' characteristics, | reduced width between the wheel arches.
which is always preferred
EWD vehicles are lighter compared to. RWD RWD vehicles are heavier compared to FWD vehicles.
vehicles.
9
Not efficient braking to block back wheel. Better :braking efticiency The more even weight
distribution helps prevent lockup from wheels becoming
unloadedunder heavy braking
10 No limitation on speed due to whirling of| Limitation on speed due to whirling
propeller shaft or sagging. of propeller shaft or
sagging:
3: Rear Engine Rear Whee Drve (RERVWDY

Fuellank
Spare wheel-

Cantrol rod
and cables

Catch
Rear drive
Gear box
Engini

Universal
Joints

Fig. 1.2.3 : Rear engine rear wheel drive

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 Automobile Engineering (MSBTE Sem-VI) 1-13 Introduction to Automables

Advantages

1. Excelent traction is available while climbing hills.

2. A larger passenger space is available for the given length of body.
3. Very compact and acceible power and tramsmission asscmbly is provided.

4. Lot of weight at the back improves aceleration and braking, rear wheels and disc brakes can be designed.to. take a
bigger amount of braking due to the weight distribution to the rear end.
5. Passengcrs are comfortable from engine noise, heat and fumes.

Front of thevehicle provides good visibility and by designing the, body to aerodynamic shape gives good streaming
lining
Disadvantages

1At high. speed, relatively high proportions of weight at the rear axle will make the car unstable at spoed. There is a
strong tendency for the vehicle to over ster.

2.. The space at the front has to be reduced to allow for the steering lock of the front whoel

3. Space utilized for engine compartment is wasted.

Dificulties with the arrangement of the engine cooling system. Nátural coolingg of radíator is not possible. Power
requirement increases, Compact engine, clutch and gearbox make servicing more difficut.

5. The wheel gets turn too sharply due to tendency of the vehicle to over steer. This necessitates the turning of tihe steering
wheel in the opposite direction to make the correction by driver.

Mid-Engine Rear Wheel Drive

This type of engine layout plaçes the engine between the two axles and the rear wheels are driven. The weight is equally
distributed between front and rear wheet.

This type of engine layout places the engine between the two.axles and the rear wheels ane driven
Normally 50-50 weight distribution

Fig. 1.2.4: Mid-engine, alf wheel drive

Advantages

Good acceleration dúe to back weight transfer.

Good braking:
Neutral handling

Front of the car can be aerodynamically optimized.

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Automobile Engineering (MSBTE Sem-VI) 1-14 Introductionto Automot
moples

Disadvantages

When accelerating some steering is lost.

Takes a lot of space.

No back seats. Difficulties with the cooling system.

Application of this layout

Ferari F430
5. Four Wheel Drive (4WD)
MSBTE:S-15,S-18S-19
OExplain allwiheel drive ype
QDraw the layout of four wheel drive yehicle, State the advantages and dsadvantages
QDraW fOur wheler chassis layoutard show major components oni
S19
To increase maneuverability.of the vehicle required to travel on rough roads this four wheel drive is provided. In this
arrangement all the four wheels of the vehicle are driyen by the engine thus making the entire vehicle weight available
for traction.

CV.joint Front drive-axle

Propellor shat

Transfer case Differential

Engine

Clutch Rear dive axie -

Gear boX

Wheel-

Fig. 1.2.5 Four wheel drive

These four wheel, drive vehicles are very useful

on Hill station if one of the wheel slipping or skidding then fhe otre
axle wheel transmit the tractive force to the vehicle. The steering
of the four wheel drive is hard to operate coman
with other type of drive.
In this arrangement all the four wheels of the vehicle
are driven by the engine thus making
available for traction. the entire vehicle wE

Ditferental

Transfer cas
Diferenfial

Fig. 1.2.6:Line Diagram

of Four Wheel Drive
Working

When the engine is started the

power is transmitted to the rear
wheel.

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 (MSBTE_Sem-VI) 1-15
Automobile Engineering Introduction to Automobiles

of a transfer case is connected to the input shaft with the big input gear, but the other
hen the shifter
mechanisnm

4er mechaism B discomects the front output shaft from the rear output shaft: In this position, the two wheel drive
obtained.
with the high gear is

Similatly the situation of four wheel drive in low gear. Obviously, four wheel drive with low gear should be used
the main transmission. Also the transter case should be engaged with the stationary
uyariably with the low gears on
vehicle since these are not
provided with synchromesh devices.

Advantages
two-wheel-drive layout.
.Traction is nearly doubled compared to a
Handling characteristics in normal conditions can be configured to emulate FWD or RWD.
2
3. Gives sufficient power, this results in unparalleled acceleration and drivability on surfaces with less than ideal grip, and
superior engine braking on loose surfaces:

Disadvantages

. The mamufacturing cost of the vehicle ishigh. .

2 More conponent and complicate transmission

3 Increase power-train mass, rotational inertia and power transmission losses

4 Increased fuel consumption compared to 2WD.

(A) Rear engine, all wheel drive (4WD)

Similar characteristics as rear engine, rear wheel drive. And other additional as:."

Advantages.

1. Better weight distribution

2 More neutral reactions.

3. Better traction on bends and slippery surfaces.

Disadvantages

1. Heavier.

2 More expensive and diffcult to desigm and build.

(B) Front engine, all wheel drive (4WD)

Similar characteristics as the front engine, rear whel drive. And other additional as

Advantages

I. Better handling capacity.

2. Better acceleration.

Disadvantages

increases weight and manufacturing.cost compare with front engine layouts.

2 Loss of some space jn the back seats legs room

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 Introduction to Automobila
Automobile
Engineering(MSBTE Sem-V 1-16
Mount Engine Vehicle
erentiate between Front and Rear
Rear mountngine
No PEKN2 K
ront mountoine
Engine
and safer than1frontmount
faster
mount Travelling is less
Travelling is faster and safer as compare to rear
engine.
engine.
vehicles having less road adhesion
adhesion due to | This engine
2. his engine vehicles have good road
compared to front mount engine.
vehicle weight carrying on
driving whee.
large
passenger comfort due t
comfort compared to This engine provide better
3. This engine provide less passenger
reduce noise, heat and fumes.
rear mount engine. passena.
more passenger space as t provides less floor area result in more enger
4. It provides high floor results in propeller
space due to dispensing with shaft.
comparod to rear engine
Rear engine required powerfal fan.
Front engine vehicles provide natural air cooling
of weight
In this engine as compared to the rear engine. the| In this engine, the rearward concetration
vehicles are less affectedd
causes the vehicle more affected by side wind at
high speed causes vehicle to umstable resuit in over
steer.

1.2.4 Articulated Vehicles:

.These vehicles having a detachable trailer supported on a platform on the tractor unit are used to carry heavy load
which must not exceed gross train weight
Engine
Fifth wheel

Dead axle

Fig. 1.2.7:Articulated Vehicle

The traifer tractor commection

is also calfed the fifth wheel. It maximum
permitted laden length and weighit i5 1> uEneters
and 20 tonnes or less than four
wheel vehicle. No time will be waste
available. in loading or unloading as several trai
1.2.5 Heavy Commercial
Vehicles:
These heavy and robust vehicle used forhaulage
purpose are paweredby diesel engine.
is gross vehicle weight a
(gv.w.)ismore than tomes. required wheetsfir
carying heavy laads. Sometimes,
3 It twin tyres fitted side by siue
more axles are added for
very heavy loads.

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 Automobile Engineering (MSETE_Sem-VI)
1-17 Introduction to Automobiles

r Divided propeller
shalt

Twinfront Centerbearing TWin rear

axles wheels
Fig. 1.2.8:Commercial Chassis
Two rear wheels are usualy provided
to increase the load capacity of commercial vehicles.
on each axde, tuin front or To ensure a balanced load
ear axles may also be used sithan arrangement of the springing shown
as in ig. 128.
For increased traction, the drive
can be transmitted to both rear axles. The reamost
carrying only can also result increased axle if made dead ar used for load
in traction.
1.2.6 Rigid Vehicles:

The tota number of driving wheels

clasify these non-articulated
with four deiving wheels
vehicles. Eg. 6x 4 indicates a sbx wheeler vehicle
The vehicle with rear wheel lade having
twin tyres fittedon side by
side

-Difererdal

Engine-

Propeler shaft

Fig. 1.2.9:Rigid Vehicles.

Van

These are used as commercial vehicle to carry light loads over short distances, Its components
like clutches, suspension
springs ete, must be strong enough to cary over stremuous duties.
Itis dressed to carry maximum load providing.more space depending on type of application.
All the power and transmission components.are arranged n a, driver compartment. Depending upon the requirement
they may be open or closet body

The open body vehicles are known, as light truck or pick up.

1.3 Ghassis, Frame and Body

Introduction

Lhassis 1s a Frenchi word was used to denote the fiame parts or main structure of vehicle. A vehicle without body is

t
called chassis. is a backbone of vehicle
and
is made steel.of moving parts of the vehicle fited on it
All
All the major units required to propel the vehicle, gives the motion and stop
it'as well as permit smooth run over
varying Toad surface is known as chassis.
It inchude the following system or components.
6) Frame or chassis frame.

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 Introductionto Automobiles
EAutomobile Engineering (MSBTE Sem-V 1-18 obiles

(i) Steering mechanism.

absorbers.
(n) Front and rear suspension, wheel tyres, axies, shock
propeller shaft, differential.
(v) Transmission system - Engine, clutch, gearbox,
(v) Brake system

(vi) Fuel tank, hydraulic pipe, cables silencer.

(vii) Storage battcry and electrical system.

1.3.1 Frame Construction:

are attached. It 1s ngid and strong
which the other automobile components
The frame is the main part of the chassis on encountered on the roads
withstand stresses, shocks and vibrations
enough to support the weight of the vehicle and to
several transverse
channels running the length of the vehicle, and
It consists of two symmetrical beams, rails, or
cros-members connecting them.
U-shaped section, welded or riveted together.
The frame are made of box, tubular channels or
frame is upswept ai
A simplified Fig. 1.3.I represent the frame shows the
longitudina member and cross members. The
the axle due to springing.
the rear and the front to accommodate the movement of

Channel section
I
Box section -section Hat section Tabular section

Fig. 1,3.1.: Cross section of frame.member

The frame taper from the rear to the front to permit adequate movement of steering wheel to give the smaller tuming
circle and steering lock.

Brackets or tubular or box section cross members provide supports the body and increased torsional igidity of te
frame.

They also provided with bumpers brackets for mounting the spring.
The construction of frame is of box shaped tubular or steel members welded together known as ladder frame
arrangement. The complete frame is fabricated by welding process.

Since the commercial have to cary heavy loads, frame construction is invariably used. Because in these the ground

clearance is larger and sufficient space is available for steer the wheel.

So the frame foe these have ondy straight member without taper toward the front or upswept at the front or rear.

The engine is mounted at the front end of the frame is supported at the three places by means
of rubber pads.
This rubber pads helps to isolate the engine from road shocks and the body from
vibration.
1.3.2 Functions of a Chassis, Frame and Body:
Themain functions are as follows:
To support the vebicle's mechanical components and body
2. To deal with static and dynamic
loads, without undue deflection or distortion.
3.
passengers, and cargo loadš..
It sustain the Weightofthe body,
4. Vertical and torsional twisting
transmitted
. Transverse lateral foreces caused
by going over uneven surfaces.
by road conditions, side
wind, and steering the vehicle.

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 Automobile Engineering (MSBTE Sem-V) 1-19 Introduction to Automobiles

6. Torque from the engine and transmission.

7. Longitudinal tensile forces from starting and acceleration, as well as compression from braking.

8. Sudden impacts from collisions.

9 Acrodynamic characteristic which determine the fucl consumption, spoed and stability in cross wind. The positve
pressure at front should be decreases and deflatcd smoothly for the prevention of cddies creations.
10. Reduction in body weight to improve capacity and fuel economy.

1.4 Requirements of Chassis, Frame and Body

MSBTE: W17

9 Stafe the various reguirements.of automobile.body

1. Space availability

There must be adequate space inside the body for the passenger and luggage both.

2. Stiffness

The car body may be considered a rigid beam which is supported on wheels at each end. The car body must have
sufficient stiffncss to prevent excesive sagging or bending in the middle.

3. Strength
subjected, which include the weig?ht
The body must be strong enough to withstand all types of foroes to which the car is
impact loads of
of the car, passengers and luggage, inertia, and side forces. It shonld also be able to.cope with

reasonable magnitude.

4. Protection against weather

protected from bad veather.
The design of the body must be such that the occupants and the luggage are

5. Torsional stiffness
roads.
The body should be sufficiently rigid so as to resist twisting movement on rough

6. Protection in accidents
that the driver is at
This is a very important parameter, consider in the. design car body. The body must be such
accident
maximum ease so that there are least changes of the accident talking place due to fatigue. However, in case the
taking place the body must protect the occupants.

7. Air lift or drag

with the square of the
The resistance of air during Tunning depends upon the body shape and size. It incTeases directly
vehicle speed. The shape ofthe body should be such that the air drag should be minimizes.

&.
Resistance to corrosion
The vehicle body is exposed to corrosion throughout its life. The body should be designed such that no mojsture shoud
be acumulated which causes rust The materials are used also be such that no corrosion takes place.

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 Automobile Engineering (MSBTE Sem-V) Introductionto Automobiles
1-20

9. The following requirements must be full filled by vehicle body:

1. It should have minimum mumber of componet.

2. It should reduce noise and withstand vibration when vehicle in motion.

3. It should be distribute the load uniformly.

4. Jtshotd have long fatigue life.
5. t shonld be light weight body.

6. t provide good vision and ventilation.

1.4.1 Load on Chassis Frame
frame are:
The various types of loads acting on a chassis
suddenly applied load for
a vehicle acted
by a heavy and
duration load :While crossing a broken patch of road,
0. Short
short duration.
striking a pot hole a vehicle
negotiating a curve, during braking, sudden
While
(Momentary load or combine load:
iomentary duration.
acted upon by a combined load for
externally applied impact load.
is subjected to
vehicle with another object, it
(ii) Impact loads : Due to collision of a
dhuration are applied on the vehicle.
application of brakes, theinertia load of short
(iv) Inertia load : Daring the
transimission system, and suspension system load,
chassis component like engine load,
) Static load : Loads due to
passenger etc. are constamtly acting on
the vehicle.
steering and body, fiucl supply system load,
vehicle beyond the design capacity.
(v Overloads :This is the overloading ofa
torsional effect so torsiona load or bendng
twisting forces caused by the road shock which caused the
The upward
(ri
loads must be taken up by frame.

1.4:2 Types of Prame Construction:

There are basic two types of frame construction:

Types of frame construction

) Conventional pressed stee

(2) Unitised consfruction

Fig.C1.4:Types offrame construction

( Conventional presed steel also known as non-load carrying frame.

(2) Unitised construction also known as integral frame or frameless construction

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 Automobile Engineering (MSBTE Sem-VI)
1-21 Introduction to Automobiles

(1) Conventional pressed steel or non-load carrying frame

Spring brackets Body brackets
Front
Overmang

Cross
members -Chassis side Inswept
members at front

Spring brackets

-Wheel base-

Upswept at rear

Fig. 141:Conventional Frame Construction

Conventional pressed stoel also known as non-load carying fraime.

ThHe
conventional type of frame is supported on the wheel axde by means of springs so the loads on the vehicle are
transferred to the suspension system entírely bya separate chassis

In this case, the Body wark is either being made of

very fexiblé materal or being made stif. Tie body is isolated fiom
the chassis defiection rubber moutings:
In this case, the vehicle loads get conentrited roumd the mounting and hence result in early failures. This comstruction
has almost disappeared in the case of cars.

Here all the mechanical components are attached to it and the body is superimposed on it These types of frame are used
in commercial vehicle and preferable in lange expensive private and open ears.

The body workis made of material like wood and completely isolated from the rame deflection with the help of nubber
mounting. This type offrame is not much suitnble to resist torsion.

There are in genieral conventionnl týpe of frame is supported three main designs för fraime rails. Their cross-sectioms
include:

a) C-shaped.
b) Boxed c Hat

A) Cshape
By far the most common, the C-rail has been used on rearly every type of vehicle at one time or another. It is made by
taking a flat piece of steel (usually ranging in thickness from 1/8" to 3/16) and rolling both sides over to form a
c-shaped beam rumning the length of the vehicle.

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 Introductionto Automobiles
1-22
Automobile Engineering (MSBTE Sem-V)

Fig. 1.4.2

ectangular tube. Modem

B) Boxed C-rails together to form a
welding two
matching four sides and thn
frames were made by piece of steel is bent into
Onginally, boxed
making C-rails in that a
process similar to background, C-shape rails
and cross-member in celer
techniques, however, use a
cros-member in the
Hat-shaped
mect.
welded where both ends
the axle:
and a slight arch over
Body mourdrg Longitadiral
r
brackets member
Cross meber
for supportng
ransmissiom

LFrort cross Cross member

member
Body mountbrg
brackets
()Box section type

Cross member

member

Cross member

-Engine unit Diagonal

mounting plates cross bracing9

Longitudinal
box frame

) X-member ype

Fig. 14.3

C) Hat

Hat frames resemble a "U" and may be ether right-side-up inverted with
or the open area facing down. Not commouy
used due to weakness and a propensity to rust, however they
can be found
a while, the hat frame gained popularity again when companies
on 1936-1954 Chevwoletcars. Abandoned
started welding it to the bottom of uni-body cas
t
effect creating a boxed frame.

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RFAutomobile Engineering (MSBTE Sem-VI)
1-23 Introduction to Automobiles
(2) Unitised Construction or Integral Frame or Frame-less Construction

Unitised construction also known as integral frame or framcless construction.

This type of constriction mostly used in cars.

In this tyye of construction, here is no frame and ned of heavy side member are eliminated and all the mechanical
component are attached to the body

These body shels are made up fzom pillars, rails, sills, and panels all welded together, and a reinforcing channe-section
under-frame with an extended sub-frame at the front is provided to replace the chassis.

In this case, the body shell and underbody are welded into single unit. The undarbody is made of floor plates and
channel and box.sections weldcd into single unit. In some cases sub fiame is also provided for isolation, flexibility and
simplified production. This construction gives more strength and rigidity.

The chassis, floor,and body are assembled by welding from a large munber of mild steel pressings. This design, reduces
vehicle weight, decrease cost, improve fucl ecomomy but increases repair cost if damage during accident.

Fig.1.44:1ntegral frame or Frame-less Construction

This assembly replaces the frame. This decreases the overal weight compared to conventional separate frame and body
construction.
passenger cars and to limited extent in bus design. Integral vehicles offer
Integral body constriction is widely used in a
the following advantages:
I. Last longer owing to their greater i.e. increased beam strength and adequate torsional stifiness.

2 Require fewer parts.

3. Involves fewer assembly operations.

4. More economical owing to weight reduction i.e. less fuel consumption and longer life.

5. In the integral construction, the sills or reinforcing members are províded under the floor.

1.5 Sub-Frame

The various components of a vehicle are bolted directy either on the main frame members or cross members. However,
sometimes the engine and gearbox are carried on a sub-frame supported both the main frame usualy at three points.
This arrangement helps to isolate the components from the effect of twisting and flexing of the main frame.

Rubber mountings are used between the engine gear box unit and the frame to rednce the vibrations. For the same
reason the body is also mounted on rubber blocks on the frame.

The chassis and the body thus make the complete vehicle body being the super structure of the vehicle. In larger and
beavier vehicles, the chassis and the body are each made as a separate unit and the bolted together.

The body is usually made from a large number of steel pressings which are welded together. The body is bolted to the

chasis at numerous point, rubber or felt strips being interposed to damp-down vibration and noise.
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 Introduction to Automobiles
Automobie Engineering(MSBTE
Sem-V) 1-24 advantageousa
although heavier is deinitely
n comparison to fully unitary construction, this sub-frame body stnucture
dctailed below:
moumtings beween body and
and smoother ride, because the
lo the occupants of the car, a quicter
Ovdes noisc or vibration.
Surb-frame are flexible with no direct feedback path for
garage resulting in reduced
mechanical repaír and maintenance by a
parts during
provides greatct access to the
and maintenance.
cost of repairs one to saying in time of repairs
car.
(It can work cqually well on all sizes of or sub-frame
units produced separately can be buit-up their
mechanical
ft simplifies producfion because different
casily. both for
layout. Only one sub-frame
meet thanthose with fuly is written are
easier to the final drive
(But the styling changes are not mamufacturer while the rear suspension and
sospension provided by certain
the engine and front
provided at the rear.

1.5.1 Basic Body Nomenclature

MSBTE:W15

nomenclature of car booy

QWth neatsketch givethe extra seat at the back
body are four doors, two
doors, pillar less, two seater with two smal
The salient features of a car of passenger compartment, folding Toof
with
partition between driver and passenger,
Iuggage space as a continuation

windup windows, clip on fibre glass roof, sliding roof

and fold flat windscreen.
many sheet metal paneis by spot welding together to form a single
solíd unit
The car body is manufactured from
rigidity to the assembled unit
Each panel is designed to give 'sufcient streingth and
naamely, otside panel and inner panel. The outside panels
The basic structure of the car.body has two type of panels
incorporate
provide the contour or the shape of the car body. The various types of curved shapes given to panels
strength into the panels. The inner panels reinforce the shell body.

They aiso provide mounting location för the various trim panels and connecting assemblies. The outer and inmer panels
are velded together and to the pillars and rails so as to-form the skeletoni of the body.

The floor of the car is assembled irst and then the pillars, rails and panels are elded in order to form the complete car
body.
The front, rear and central panels are made by pressed steel panels. Each unit is so shaped that gives lower profile
it a
ad accommodate more passenger space. For additional strength more metal strips arë welded at different floor panel
This strip prevent excessive vibration. The rear wbee! house inner panels and rocker panels are also welded to the
The whoel house panel is such that it gives enough clearance
fo
for up and dowa movernent of wheel when car is moving
on road.

The cow assembly or the frönt portion the

of car is made from many smaller panet stampings of steel sheets. 1
windshield opening frame accommodate
the front glass which is curved in shape
depend on car design
The top outer cowl panel is sometime vented to allow fresh air
and indicating devices required to operate
tó enter the car. The dashboard provided with warming
the caT. The instrument panel welded
is to the cowl or bolted to the cow
The pillars on the sides
of the cowl are meant for fastening the
front door hinges and the cowl fickle
is the sheet metal panel which panel. The fire wa
separates the driver cabin
and engine space.
This wall is insulated
to protect the engine from
heat and noise which penetrate inside
assembly is usually welded
to the rocker panels and floor
from the body. The OR
panel.

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 Automobile Engineering (MSBTE Sem-VI) Introduction to Automobiles
1-25

he rear doors and hinges are supported by the central pillar. The centre pillar also support the striker plates of the ron
dor. The roofrails and centre pillar are ausually of box section which gves maximaum strength to the body.
Thedip moulding of U' shape echnnnel is added to side rais of the roof. Whese function is to catch the water from
oof and direct to the back of the car during raining. The roof panel is welded to the top side rail.
rear window and front windahield frame are
The attached to the roof panel by spot walding. The rear quater panels are
welded to the rear wheel house panel, the floor panel and the
rear of the rocker panel.
The trunk lid of the caris atached to the body with the help
of hinges, lacking armangement is also provided for the rear
compartment.

Emgine compartment made from diferent sheet imetal panet. It covers

is the firont wheels and thereby prevents dirt and
mud being thrown off by the tyres on the engine and
car body
The wo fenders vwhich cover the frot wheels ae connected by the radiaxtor support. The radiator support are boted to
the cross member.
Bumpers ane at the front and the rear of the car which protect the front and rear portion from damage during light
collisions
They are made from heavy gauge steel.It is of channel. secion which open side turned inward. These are riveted to the
énds of the longitudinal member of the car frame or front body rai.
Wind screen pillar
LSUally box section

Front bulk head is well Rear quarter pillar

Sraced to minimise SUpports roof
wisting of thie body
Stengthene Rear wing

forfrot
SUspensiön
attachiment

Door pillar also

Supports root
Rear-seat pan
helps to stifer floor
Propeller -shaft
tonnel helpsto
stifen floor
Frort wheel adh- Floor panes
nbbed for stifnéss

Fig.1.5.1: Car Body Nomenclature

1.6 Significance of Body Streamlining

Streamliníng, in serodynamics the comtouring of an object, such as an vehicle body, to reduce is drag, or resistance to
motion througha stream of air, A moving body causes the air to flow arouind i in definite patems, the cwomponents of
which are calledstreamlines.
A streamline body of an auntomobile is a shape given to vehicle body which lower the friction drag as the vehicle moves
through the air. Drag is a force that slows down motion, fiction drag is a special kind of drag. It occurs when the fluid
closest to the object sticks tó its surface, exerting a force that opposes the object's motion.

Advantages of Body Streaming:

1. The aerodynamic body shape reduce air drag on the front end of the vehicle which creates resistance to motion of
vehicle. The aerodynámic shape at the rear reduce the problem of vacuum ie. creating a hole at rear end. While moving
an steep road. This create pulling effect on vehicle which resist forward motion and because of aæro shape the air tlow
can be diverted in this region.

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 Introduction to Automobiles
Automobile Engineering (MSBTE_Sem-V 1-26 depend on acrodynamic
can be
fucl but it
it rarc 10 to 15% on engine reduces. It ale
2 The acrodynamic shapc can improve fuel conony So
well as life as the load
engine efficiency as flow over andunder and
components vehicle. Ii improves optimizing the air
C
increases speed of vehicle. It also improve cooling
cffect to the engine by
uniformly and properly
distriouion of air pressun
comfort due to
component. It improve the ride
ngine
over a car body.

Aerodynamics aspect W:16,S17:W17 S18,W-18, -19

.Need and Importance of S15,W15,S-16,
MSBTE WA4,
W-14, W-17, W.18
Importance of Aerodynamlc shape of car Doay S-15
Gve the
aerodynamic shape of body
Ustify W15
improves performance of venicle
Ustiy Aerodynamic shape of an automobile

State importance of aerodynamic body of car

(W-16,S-18, S19
State its advantages.
Whyaérodynamic shapes is important in autormobile bodies?
to aerodynamics.
State andexplain different forces.acting on the vehicle body related

reduce drag and wind nóise, minimze noise emission and preve
In automotive aerodynamics is the main aim to case
speed. Air is also considered as a fluid in this se.
undesirable lift forces and other causes of aerodynamic instability at high
aerodynamic characteristics. There are three forces actino
The body shape and size of the vehicle must have acceptable

on a vehicle

(1) Air drag force acting in a direction of vehicle motion.

Aerodynamic lift acting vertically upward

) Cross wind fore acting in lateral direction,

The aerodymamic aspects will be more expensive but lowering aerodynamic drag the fuel economy of the fastest vehick

can be improved.

(a) Aerodynamic drag

Acrodynamic means the behaviour of the air motion relative to

car body. Aerodynamic drag is also called as ar
resistance.

Total aerodyniamic drag of a vehicle include many factors

such as Form drag is also known
drag (576) is the drag caused by the separation
as pressure drag or profle
of the boundary layer from the surface and
separation. It is depend on the shape of body,
the wake created by te

Induced drag (8%) skin friction drag

(10%) arises from the friction
viscous drag in the boundary layer around
of the air against the surface and is caused by
the automobile body.
Interference drag (15%) is created
by mixing of airflow streamline
and cooling and ventilation
the region of turbulent flow downstream drag (10%A)The wake is
ofthe moving automobile body.
Total aerodynamic drag
(P)=Cp V
Where

Cdimensional dragcoeficient
p air densityin kg sec'/m
V velocity ofcar in m/sec

A projected area ofthe vehicle

from the front, m

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EAutomobile Engineering (MSBTE Sem-VI) Introduction to Automobiles
1-27

D0 rom the above equation it is necessary to select a careful nrofile of size of car to achieve low proe us
cocfficient.

Lift

Air cannot fd
vacuum behind
indow and trunk
Air velocity
increase
Drag
Urag

Down force (ift)

Fig.1.7.1

200
I50

100

10 20 30. 40 50 60 70 80 90 100
Speed (mph)
Assumes powertrain effidency of 20%

Fig. 1.7.2

its attendant
should be continuous and separation of the boundary layer with
Stream line of air flow around the vehicle
always associate with particolar surface area and it should be
vertices shoutd be avoided. Skin drag coefficient is
surface.
decrease by smooth and well polished of body
body
handle aerials and badges which project outward from normal surface of
The accessories such as miror, door
below the vehicle such as axle, propeller shaft, tow bar also contrbute"
produce interference drag and projection
be avoided
interference drag hence such projection should

(by Aerodynamíc lift

caused by the pressure distribution on the vehicle body. It is expressed
Itis the vertical component of the resultant force
by the equation

Where, C = dimensional lift coefficient

are undesirable effect. The aerodynamic lift tends to reduce the pressure
The aerodynamic lift amd pitching moment
loss of traction on the rear axle.
between the tyre ánd the ground. This causes the loss of steering on the front axle and
rocking chair or rotating action
Pitching causes rear wheel ground and reduce available traction. It is the
lit off the
pitching, the front suspension moves out or
about the transverse axis through the vehicle parallel to ground. Due to
phase with the rear resulting in rocking effect in a vehicle.

Kasaledgi
YTch
YPCations

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 Introductionto Automobiles
Automobile Engineering (MSBTE Sem-VM 1-28

c)Side force wich produce a side

tirust
during turning
force acts on the vehicle
The imbaland of the wheel due to centrifiugal
direction of molion
ot ine venmcle. This ig

the makes some angle with the

0Suslain that force the plane of wheel
flexble.
achieved by the distorion of tye which is force produce to countct actk
slip angle and the
sustainthe side thrust is known as
angle fom during taking turn to
e
the side thrust is called as Comering force.

d) Yawing movement (Bouncing) known as

goes up and down which is
body. When complete body of vehicle
the complete known as frot end boume
It is vertical moment of front end or rear end the bounce is
Depending upon the movement of
Dounce or bomcing.
or Tear end bounce.

e Rolling movement
force act during comering.
longitudinal axis produced due to centrifugal
the movement of a vehicle about its height
Itis a vehicle is at a certain
applied at road levels but the centre of gravity of
forces are cetrifugal force
The retarding and comering the vehicle owing to
produced about the longitudinal axis of
During cormering, a turning
couple is Ttis resuts in a motion
contact of road and tyre patch
gravity and forces acting at the point of
acting at centre of
known as rolling.

A combination of
roling and pitching is called diagoml pitch hydrolyic
pitch and roll control bars,
above suspersion movements' anti-roll bar, stabilizer,
In order to control all the
provided to a vehicles.
systems, mechanical levelfimg devices et. are
Yaw
(8ouncrg)

Roling

Pitching

Fig. 1.7.3:Body frame

1.8 Alternative Fuel

1.8.1 introduction
increasing pie
other than petroleum. The rapid depletion of fosil fuels and
Ateinative Fuel are derived from sources resene
known petroleum
search for alternative source of energy. The scarcity of
of crude oil made the reseachers to growing demmd is b
attractive. The most feasible way to meet this
will make renewable energy resources more
ole
automobiles made the diesel engines to play a vital
urtilizing alternafive fuels. The enormous growth of
increase in vebice
is increasing day by day due to the
transportation sector. The se of diesel in the transport sector
popnlation.

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Autlombie Engineering (MSSTE Sem-V
1-29 Introduction to Automobies
1.8.2 Need:
.As a result gases from fosil fuel emision have causad and cortinuing to caused geat danage
to the atmosphere such
effect
as green house and acidie rain. Altermative füels wtich
are renewzble and eco friendly reduce
the dependency on
fossil fuels and they help to preserve the atmosphere by reducing
the emissicn levels. Tte burning
higher levels of C0, and other gases in atmospbere affecting of fosil fuels create
the green bouse effect The soareity coaveational
fuels, growiag emissions of combustion causing polhitants
of fosil
and their increasing costs will make
biomass sources more
attrective. The comvertional fuel as diesel exhaust
may cause kng cancer and other
repiratory diseaes The diesel
emission has been classitfied as human carcinogen.

1.8.3 Fuel characteristics of CNG and LPG:

.CNGis alled compressed natural gas, and it is mainly a methane gas which is compressed
240 bars. CNG obained from coal bed methane at pressure between 200t
and oil wells. CNG is
a good fuel substirure for vebicles. CNG is
lighter than the air.
LPG is called liquefied petroeum gas,
and it is a mixture of propane and butare
Hquefed st the temperature of 15 C
and a pressure betuween 1.7 to 7.5 bar. Propane
is atomatically generated from the gas
extracted. Propane is usualy used for heating, felds wiaie atural gas
coaking or agricultural uses LPG is heavier than
flarmmable. LPG vehicles the gas air, hence it is ighly
mixe reedily with air, allowing fer more complete combusion.
than Tegular gasoline, but LPG vehicles æve tower The fuel costs less
energy per mit voume, so its fuel ecoomy and efficieocy are
lower.
LPG vehicles give a longer engine life due its ciean
to buruing characteristics. LPGis a gas at room temperahure,
liquid when pressurized the required pressure varies according but a
to the composition of the mixtre). It is usualiy stored
at around 10 bar.

CNG fuel characteristics

CNGCharacteristi alne
Vapour density 0.68

Auto ignition 700 C

Octane rating 130

Boiling point (atm. pressure) 162 PC

Air fuel ration (weight) 1725

Chemical reaction with rubbe No

Strong pressure 20.6 MPa

Fuel air mixture.quality Good

Fuel air mixture Low

Flame speed (m/s) 0.63

Combustion ability with air 4-14%

Vaporisation energy (MJ/ m) 215-276

Many things are considered when determining the. viability of n alternative fiuel incuding emission, cast, fuel
availability, fuel consumption, safety, engine Tife, fueling facilities, weight, space requirement for fuel tanks and the
range of a fuly fueled vehicle.

lrcaratrdgë
iiaas

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 onto
Introducuon10Automobiles
Autom

marginaly cheaper, cleanct

Automoble Englnorlng (MSBTE, Sem- 1-30 vehicle.CNGILPG is and
power the
CNGAPG engine uwses Compresed natral gs to
cnvronmentally-ftiendlly thnn ordlinary gasolinc or dienc.
situated in the tr nk.This
1.8.4 Tho CNG Engino and is tank
atached to the vehicie,
which has to be
The CNG engine usesnssecondficltnk gas used compressed. icle uusing any onefuel
vehicle
is usunllylarger in size, as it has to kecp
tha choice to run the
deiver has a
engine. Thò lhe difierent tanka
nks,dravinA
from engine to can allernute between
TThe pressure range may vary the car
i means that
dashboard. This
switeh on the
pressing a
fucl from either.

Working of CNG Englno gasoline and CNG vehicles.

the two, contains parts ofboth the gas compres
vehicle is combination of of tank is large to keep ressed.
CNG a size
A
situated in the trunk. The
separate fucl tunk switch
CNG engine uses a simply operating a
he vehicle using any one fuels by
series of highly pre.
The driver has a
choice to run the
the tank is sucked through a
compressed gas in
sclects the CNG tank, the
Once the driver
regulator.
amount of tucl nieeded by the
fuel injectiom
inie
lines until it reaches the
pressure on the gas to match the
regulator is to control the
The function of
cngine.
systcm of the vehicle move into the fuci inieri
level, the solenoid valve allows the gas to
reaches to acccptable
When pressure of gas
the proper proportion in engine.
system.and mixed with ait in downmward. This
to the engine. During
this the piston moves stob
into the suction manifold
This mixture is then enters required compression ratio
mixture is compressed to a wfi
suction stroke. The gas and air
is called as induction or chamber.
and it is ignited in the combustion
increases temperature and pressure
temperature and pressure which acts on piston t
combustion large amount of heat energy is released increasing
.Due to vehicle forward.
developing power which moves the
move the piston downward

Gas and air mixture Exhaust yalve

Compressed. Temp Diesel ignites pens on
and press nses. causng gas pward stroke
Pilot dlesel injecled expelling gases to
gnite and forces
through fuel valve piston down. atmosphere.

sasSand an
mixtureenters
cylinder via
inlet valve

1.Suction 2. Compression 3.Power 4. Exhaust

Fig 1.8.1

1.8.5 Liquid Petroleum Gas (LPG):

.LPG is obtained by refining of crude oil.

LPG contains propane and butane

and propylene and is most
pure.

Ted

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 Automobile Engineering (MSBTE_Sem-VI) 1-31
Introduction to Automobiles

As vaporization of propane occurs at atmosphere temperature and

pressure hence it burn move accurately in engine
cylinder.

Due to complete combustion emit less HC and CO and easy ta control exhaust cmission.

At normal temperature propane lires easily hence cold starting is easy and produces power without stumble..

The main difference between petrol and L.P.G is that the L.P.G is dry fuel and enters in engine cylinder in vapour state
while petrol enter in engine with fine tiny liquid droplets.

Regulator or reducer, also called as a vaporizer and is located in engine compartment and performs same functions as
that a carburetor in a gasoline engine.

It uses heat from the cooling fluids to vaporize the propane into gas form. It includes am electronic circuit that cuts the
flow of gas if the engine stops or stalls. The regulator is usually smaller than a regular carburetor.

Working of LPG:

The propane fucl system is a completely closed system that contains a supply of pressurized LPG.

Since the fuel is aready under pressure, no fuel pump is needed.

From the pressurized fuel tanks, the fuel flows to a vacuum filter fuel lock. This serves as a filter and a control allowing
the fuel to flow to the engine.

The gas (propane) supplied from the fuel tank through the reducer, in which the gas changes from the liquid to the
gaseous state, is injected into the air intake just before the turbo pump:

The mass flovw rate is adjusted by gas injector controlled by an electronic control unit(ECU), which adjusts the entire
system based on information obtained from load, RPM and temperature in the exhaust system.

Exhaust Gas temperature sensor. acts as.safety control, if the exhaust temperature rises, the system immediately reacts
by reducing gas fiow through the computer control, the engine is not at risk for knock combustion or abnormal wear i
comparison to an engine without an LPG system installed

A solenoid valve must be installed on the fuel line in between the tank and the engine. This valve cuts the filow of LPG
when the car is running on gásoline and when the engine is shut off It aso has a filter built in that removes any dirt that
may be in the füet.

The carburetor mixes gaseous propane with air.

Air flow itothe engine is controlled by a butterfly valvein the venturi.

micture is controlled by a fuel metering valye operated by a diaphragm, which is controlled by the pressure in the
The
intake manifold.

The idle system is an air bleed, similar

to a gasoline engine.
n ac,except for the fact that the propane carburetor does not require a fiel bowi, the two carburetor types are
basicallythe same:
Advantages:

MSBTE: W-14,S-16, W-16, S-17, S-18, W-18

State the advantages.of. LPG and CNG operatedengines W-14 W-16, S-17
22gyantageS.and disadvantages of L.GIGNengine.gMES
tate the advantages ofLPG
and CNG operated vehiciesS S18, W161

Techtaundgi
PuDitatioas

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 Introduction to Automobiles
FAutomobile Engineering (MSBTE Sem-V 1-32
1. The fuel cost is less.
dioxide (C0), unburned hydrocarbons,
Less pollution and more efficieney: It emits 99% less pollutants carbon
(SOx) and particulate matter t n petrof.
Carbon monoxide (CO), nitrogen oxides (NO,), sulphur oxides

3. It is safer for vehicle. The CNG fuel tank is made of thick wall % or % inch. So they can withstand dynamic exposion,
crashtest, direct gunfire
As it is lighter than air, CNG dissipates quickly and has a higher ignition temperature.

4. Increased life of lubricating oils, as CNG does not contaminate and dilute the crankcase. oil. No nced, of oil change
before 19300 km and reduce vehicle maintemance. Being a gaseous fiuel, CNG mixes easily and evenly in air.

CNG-powered vehicles have lower maintenance cost than ofher tydrocarbon-fuekpowered vehicles.CNG mainly
consist of methane with less percent of other hydrocarbon lke ethane, popane and hyutane. Less pollutant, does not
restrict vehicle performance and more coiomical than petrof

6. Due to its antiknock property, CNG can be used safely in engine with compression ratio as high as 12: 1 compare to
gasoline engine, Because CNG has a higher octane number than petrol, CNG engines.operate at higher compression
Tatio without knocking
. CNG fuel systems are sealed, preventing fiuel losses from spils or evaporation.
Disadvantages

The space required for CNG.cylinders and their weight about 300 pounds which
is more in most of the application.
2 While as compare to diesel engine compression
ratio of CNG is lower, so fuel efficiency of these engise is 10-28%
lower than diesel engine.

1.9 Electric Vehicles

1.9.1 Introduction:
In the electric car, the engine is replaced by an electric motor which
gives electrical energy from aset of þatteries.
electric vehicle also réfered to as an electric A
drive vehicle, uses one or more electic motors traction motors 10
propulsion. or

Three maintypes of electric vehicles exist,

(a) Directhy powered from an extermalpower station,
eg. clectric train.
(b) Powered by stored electriçity originally from
an extermal power sounce e.g. electric boats.
(c) Powered by an on-board electrical generator, such
as an engine (a hyhridelectric vehicle), celi.
orahydrpgen.
Electric vehicles inchude electric cars, electric
lorties, clectric aeroplanes,
electric boats, electric motony es ad
scooters and electric spacecraft.

1.9.2 Need

The fast.depletion of crude ail reserves, freqnent price coaventiona

hike and high atmospheric pollutionnorom the
automobile, it is the need to reduce ihe use operazlod
of conventional fuel the antomobile. So the hattery
electric and solarvehicle are the best altermatirve. The
in So of 1

se
vehicles
social and environmental impactsof electric and hybrid
include effects on mobility and travel, electricity supply consunption,
system operation, petroleum and on fuel
pollution and trafic noise.
fediad
ltotien

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 Automobile Engineering (MSBTE Sem-VI)
1-33 Introductionto Automobiles
Hybrid electric vehicles (tHEVs)
are alternatives to conventional vehicles, and have a critical
role in migrating climate
change and saving oil resources.
Petroleum consumption for transportation
purposes will decline, but the benefits are
dependent on thetype fucl
of used to generate recharge clectricity.
Solar automobile uses solar batteries convert
to solar energy into electrical energy. Which can
motor to run the car. The conventional be used small electric
solar cell, or photovoltaic cell,is
an electrical device that converts the energy of
light directly into clectricity
by the photovoltaic cffect,
which is a physical and chemical phenomenon but delivers
power only about 0.5%
of the total light energy it absorbs. In
the electric car, the engine is replaced by electric motor
which fetes electrical energy from an
a set of batteries.
1.9.3 Working of Electric Vehicles:

The layout ofan electric vehicle shown

in Fig. 1.9.1.

Acceleration

Brake
Charger Drive Drive
Batery Matar iransmi
Whees

DCIDC
Gorverte

12 V

Fig 1.9.1.:Layout of an Electric Car

The battery used in electric car is lead-acid battery hose only disadvantage is relatively low specific energy
(27-33 Whkg)

Sodium- sulphur type with specific enengy 78-81 Whkg is a good alternatve but of very high cost amd its tise is yet

limited.

The drive controller takes powers from the batteries and delivers to motor.

The dive comtroler consists of twa variable resistars operated by acelerator pedal or brake pedal.

Accelerator pedal signa sent to drive controller through resistor to adjust the power to be delivered to the motor.

Two resistors (potentiometers)

are used for safety.
The drive controller gets signals from both
the potentiometers but operates only if the two signals ane equal
ne darve controller takes in about 300 volts DC from the battery set and coverted into maximum of 240 volts three
phaseAC tosend to the same
motor.

Tedh Kauledy
Pupicati08s

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Automobile Engineering (MSBTE Sem-VI)_ Introductionto Automobile
1-34

1.9.4 Advantages of Electric Vehicles:

Advantages of electric
vehicles

1. Rapid acceleration

2. Noise-free cperation

3. No exhaust fumes

4. High reliability
5, Easy maintenance

6. Regenerative braking

. No
loss of pawer in idling

8. Easy to drive

Fig.C1.5
1. Rapid acceleration.
2. Noise-free operation Electric
: vehicles typically have
whether it is at rest less noise pollutionthan an internal
or in motion. combustion engine veticle,
3.
No exhaust fumes:
Electric vehicles release
addition, is generally almost no any air polhutants
it easier to build pallution control at the place where they
systems into centralized.
are operated. In
umbers of cars. Electric vehicles power stations
emit no tailpipe CO,
or pollutants such as
than retrofit enomos
uSe. NO, NMHC, CO and PM at the
point of
Electric motors do
not require oxygen, unlike
internal combustion
High reliability : engines.
Due to absence of numerous
flywheels, starter motor, engine parts, such
distributer, spark as pistons, connecting
plugs, valve tappers roads, cams, valves,
5. Easy maintenance: ctc., electric car bas clute
Due to very small number high reliability..
of moving parts in electric
6. Regenerative braking: motor, the maintenance
When we take foot is much easie.
energy of motion off the accelerator
back into the battery. pedal, the motor
ABS brakes are automatically becomes a generator, *

climbing uphill is recovered suking

on the way down, rather applied in emergency stops. Energy
tham in sp
7. No loss of power buring up the brake
in idling : Electric motor linings.
in case of conventional does not need
vehicles. to idle and stops,
thus avoiding
the power loss during ra
8. Easy to drive: No clutch
operation or gear
šhifts are required.
1.9.5 Full power is available
Disadvantages ofElectric Vehicles as soon as you stepon pedal
. The range is limited
to about 100-150 km
the

becauseofthe
2 The top speed is quite
low (about 60 km per
hour).
need to recharge
the batteries.
3. Life of batteries is
quite short, which
expensive per kilometer means very
high
run compared to the conventional replacement costs. Thus
petrol engine
vehicle.
it is found that it 1s ch

Techka
Psucati

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FAutomobile Engineering (MSBTE Sem-V})_ 1-35 Introduction to Automobles

1.9.6 Limitations of Electric Vehicles

1. High acceleration by high torque from the motor is lowered eficiency due to higher losses in the form of Joule heating
in the motor windings caused by the high electric current.

2 This cnergy loss increases fourfold as the input curent is doubled, so the practical limit for sustained torque from an
clectric motor depends on how well it can be cooled.during operation
3. There is always a compromise between torque and energy efficicncy. This linmits the top speed of electric vehicles
operating on a single gear due to the need to limit the requred torque aind maintain efliciency at low vehicle speeds

1.10 Hydrogen Fuel Cell

A fucl cell is a device which produce electrical power through a chemical reaction by' converting
a fuel (hydrogen) into
electricity. Although fuel cells and batteries are both considered
electrochemical cells and consist of similar structure,
finel.cells require a contimuous source
of fucl and oxygen to run similar to an internal combustion.engine needsa
continuous flow of gasoline or diesel.
A hydrogen fucl celt consists
of three main components an anade, the negative post of the fuel cell, athode the posifive
post of the fuel cell and an polymer electrolyte membrane to
create the chemical reaction detween hydrogen gas (tH
and oxygen gas (0,) as fuel

First, a hydrogen füel is channeled to the anode through

flow fields. Hydrogen atoms become ionized (stripped of
electrons), and carry only a positive charge. Then, oxygen enters
the fuel cell' at the cathode, where it combines with
electrons returning from the electrical circuit and the ionized hydrogen
atoms.
Here, the oxygen atom picks up the electrons, then it flow through the electrolyte combine with
to the hydrogen ion.
The combination ofoxygen and ionized hydrogen serve as the basis for the chemical reaction.
A polymer electrolyte membrane (Proton Exchange Membrane) permits thë appropriate ions
tó pass between the anode
and the cathode. If the electrolyte gave free control for all electrons or ions pass freely, it would
to disrupt the eh mical
reaction. At the end of the process the positively charged hydrogen doms react with the oxygen to form both
water and
lieat while creating an electrical charge.

Electric curent

Water and
Excess fuel heat out

HO

Fuel In Air In

Anode Cathoda
Polymer Electrolyte

Fig.1.10.1:Hydrogen Fuel Cell

Kaouledgi
Tedh
tatios

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 Introductionto
1-36 Aut
Automobile Engineering (MSBTE Sem-Vi)

Cell
Advantages of Hydrogen Fuel
and storing them.
It play important role in providing power
more efficient than I.C. engine.
This fucl ellare two to three times
location.
Fucl cell can provide electrical power for remote
and play significant role in transportation industry
Fucl clls are used in both stationary and motive power

It emit only water vapour assuming no leakage of hydrogen gas.

Tt is environmental friendly

Disadvantages of Hydrogen Fuel Cll:

It still costs a considerably more.

Itis dangerous.
Applications :

Cars, trucks, buses, and recrcational vehicles.

Material handling equipment.

Act as a primary power source för ingh volume data oenters or commercial, industrial, and residential buildings.
Backup power sourçe to critical computer and communication
networks.
Generating power on-site.

Q.1 Give classification of automobile with

R Review auestions
example.
02 Draw tabelled chassis layout of tnuck.
Q3 Differential
chassis and frame.
Q4. Diferentiateframe and frameless
vehicle.
Q5 Define vehicle layout and state
its significance.
Q.6 State various types of automobile
bodies
07 What are the types of vehicle layout.
Sketch and explain any one.
08 Compare front engine
and rear engine drive onany
four point.
Q9 State the advantagesof
front wheel dive.
Q.10 Enlist the various
types of autornobile
bodies.
Q.11 Define Aerodynamic.
Why aerodynamic
Q.12 Name major component aspects are important
of automobile in designing vehicle.body.
Q13 State the Significance and state the function of
of vehicle layouts any four components.
Q14 Diferentiate Between
Rear Wheel Drive.
Q15 Explain working andFrontWheel
of CNG engine. Drive.
Q.16 State the
advantages of LPG
Q.17 Draw layout and CNG engine.
of electric car
and explain itsworking.
Q18 State the Functions
of a Chassis
Q.19 various types andFrame and Body
of foads acting
Q.20 State the on a chassis frama.
advantages of Integral
Q21 State the Significancea body construction.
of hody streaming.
0.22 State the necessity
of Alternative
0.23 Enlist the Fuel Fuel.
characteristic's
of CNG.
a24 Draw the diagram
of Hydrogen
0.25 Describe the Fuel Cell
working of Hydrogen
Fuel Cell

Irchu
PACa

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 Autcmoble Engineering (MSSTE Sem-V Table of Contents

2-10
UNITN 24 Types ot Transtiss rSystens.
211
Chapter 2: Automob!le Transmission Systems 25 Funcson and Necessity of Gear Box
2-1 to 2-42 212
TypesotGe Bax
26
Sylabus Bor 2-12
25. Constant Mest Gaar
21. Functlon and Necessity of Clutch: Requirement of Clutch, 2-16
Srchromest Gear Bar
Classification of, Clutch, Warkdng Princdple of Cutch, 262
(Autarnated marua
Construcion and Working of Single Plate (Coil Springand
27 naic tansTSsion 2-19
Diaphragm). Mutiplate Clutch and Centritugal Clutch.
ansrisso
Function and Necessity of Gear Box Manual Overdriv*
28
Transmisslon: Classification of Gear Box, Construction and
28.1 Coristruction and Working otan Overdrive
workiny of Constant Mesh and Synchro Mesh Gear Box with
power flow diagrams. Fluid Flywhse.
29
AUoNODre

Transmission: Functiorn,
Constuction and 29.1 Fluid flywheet or fuid coupling or fuid chutch .

23 Sml Aotouetie Automatic Transmission: Fluid

Woking of Overdrve,
Constnuction and Working of
Fluid 2.9.2 Acvantages of Fiuid Flywhas!
Ruhee Anction Function, Construction and
Fyuhest Torque Coverter Train 29.3 Disatvantages of Pluid Pywhes -24
Converter, Epicyclic Gear
Warking of Torque
Epicyclic Gear Train.
Function, Construction and
Wcrking of
29.4 Characteristic of Fiuid Flywhes
Function, Necessity and Types
Propeler Shaft Assembty: Torque Converter.
Function necassity of Uaiversal and
and 210
of Propeliler Shaft,
Sip Joit 2.10.1 Comparison between Ruid Coupling and Torque
Necessity of Fina Drive,
2.5 Finat Drive: Furctio and Converter.
Differential, Working Principle, Construction and Warking of
Differential. 2.11 Epicycic Gear Train (Box). 2-25
Axde, Function and
2.6 Axles: Signiticace of Live and Dead Propeller Shat.. 2-2
Axde, Types of (Front) Stub axde,
212
Requirement of Front
Function; Construction and Working at Semi Floating and Functions af the Propeller Shat. -2-28
2121
Fuly Floating Rear Axde.
2122 Construcion and Working of Propeller Sheaft 2-28
21 Introduction 2-1

Definibion and Necessity tor a Clutch. 2-1 212.3 Types of Propeller Shaf...
2.1.1

2.12 Requirements of Clutch 2-2 2.124 Whiting ot Propeller Shat.

Working Principle of Clutch 22
2.1.3
213 Firal Drive and its Type-
2.14 Funcions af Cutch. 23
2.13.1 Fina Drive Classification.
21.5 Dasign Consideration of fiction clutch
2132 Functions ot Final Drive 231
Selecion of Clutch 2-3
21.6
2-31
Ciassification af Cutch. 2.13.3 Construction and Working of Final-Drive
22
2-32
22.1 Single Plate Ckutch 2.134 Types ot Bevet Gear Final Drive.

Cch 2134.1 Spiral eva..

3 Diaphragm

231 Diserence between Col Sping and Diaphragm 233

2134.2 Hypold Gear.. ****** ****** ****

Spring Type Castch. 2-6

2-94
214 Differental.. ************

232 Maut-ptate Ckc .27

24 214.1 Need of Differential. *****
234
233 Seni Centrituga Cluich
2-34
234 Certiugal Cth. 29 2142 Furcions oft the Ditferentia.
 2.14.3 Constuction and Working of Dilferenda . 2-3
215 Axde. 2-36
215.f. ntroducfion... 236
..2-37
215.2 Functions and Requirements of Front axde.

215.3 Componert of the Frot Axde. 2-37

216 Stub Axde.. 2-38

216.1 Type of Stub Axde... .238

217 Rear Axde .2-39

217.1 Rearude Shat Supporting.. 240

2.17.2 Dmerence between Lve Rear Axte

and Dead Rear Axde 241

 Automobile Transmission
() SystemS
Unit-1
Syllabus:

2.1 Functton and Necessity of Clutch: Requirement of Clutch, Classification of Clutch, Working Principte Clutch,
of
Construction and Working o Single Plale (Colil Spring and Diaphragm), Multiplate Clutch
and Centrifugal Clutch.
22 Function and Necessity of Gear Box Manual Transmisslon: Clasification of Gear Box, Constructioni and
working of Constant Mesh arid Synchro Mesh Gear Box with power flow
diagrams.
2.3 Semi Automatic Transmission: Function, Construction and Working of Overdrive, Automatic Transmission:
Fluid Flywheel: Function, Construction and Working of Fluid Flywheet; Torque Converter: Function,
Construction and Working of Torque Converter, Epicyclic Gear Train: Function, Construcion
and Working of
Epicyclic Gear Tralin:

2.4 Propeller Shaft Assembly:: Function, Necessity and Types of Propeller Shaft, Funiction and necessity of
Universal and Slip Joint.

25 Final Drive: Function and Necessity of Final Drive, Difrental, Working Pinciple, Construction and Working ot
Differential.

Axdle, Function and Requirement ot Front Axde,

2.6 Axles:Significance of Live and Dead Types ot (Front) Stub axle,
Function, Construction and Workiñg of Semi Floating and Fully Floasting Rea Abxde.

2.1 Introduction

In order to propel the vehicie, a particular ype of speed and power changing device is required to transfer the power
developed by the engine to the driving whecl due to constantly changing requirement demanded on the engine and its
inherent limitation. These device are generally knoiwn as transmission. Transmission basically defined as an assembly
ofparts inclading the speed-changing gears and the propeler shaft by which the power is transmitted from an engine to
alive axle.
It includes all the companents between the engine and the road wheels used for transmission like clutch, gear box,
propeller shaft, differential andaxles.

2.1.1 Definition and Necessity for a Clutch:

MSBTE:S-15, W:17

hat iS cutch? State functions and dassification of friction clütches S15

QState hefunctions of dlutch. (W-17

on:Cluteh 1sa device used in transmussion system of a vehicle to transnmit the rotar no9
onesshaf
LOcated between
O Secona shaft of which as
are coincident with that of first Thus, the clutet. 15
the engine and the transmiSsion system.
the
power (Tarque) transtnits from the engine to the driving wheels through tne
iS engaged,

eticle moves. When the clutch is disengaged, the power is not transmitted to the driving wnet d e
the
vehicle stop, while
the engine is still unning.

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 Automobile Transmission Systems
Automobile Engineering (MSBTE Sem-VI) 2-2
disengaged during the gear, shiftina. 1while
engaged position. The clutch is
In a vehicle, the clutch is always in the operating clutch
by the peial
idling the engine. It should be disengage
stopping the vehicle or during braking and when
this avoids puting under strain on
sudden jerk motion of the vehicle and the
When clutch operated properly it prevents
remaining part of the power transmissio.
the engine amd the
transmission.
The clutch is located just behind the engine, betwecn

2.1.2 Requirements of Clutch:

The Main Requircments of Clutch are as follows:

I. It should be able to transmit maximum torque of the engine.

shocks.
2. t should be engage gradually to avoid sudden jerks or
during clatch operation.
3. It should be able to dissipate large amount of heat generated

4. R should be dynamically balane, för high specd engine.

during power transInission.
S. T should have suitable mechanism for damp vibration and rediuce noise

6 Size should be small and óccupies less space.

7. Easy for operating so that it can operate by small effort of drive.

8 It shoukd be lighter in weight.

2.1.3 Working Principle of Clutch:

A clutch is a mechanism'used to transmit the rotating motion of one shaft to another whicn desired and the axis of both
the shaft are coincident.

It works an the principle of friction. It comnect the engine shaft and gear box shaft. The transmission of power cam be
more roftating concentric surfaces, called as riction plate.
afected by iricion betwen two or The ficion plates cam be
presed firmly against one another by means
of axial force provided by spring and the pressure plate.

N pressuT

N RPM

(b)

Fig. 2.1.1

When it engaged, the clutch tends to otate as a single unit.

The rotating speed of the
depends upon the friction force which concentric surface or other sharts
is proportional to axial force applied by
spring. The torque (power) transmnud
by clutch is given by

= WR
T
Hence power transmitted
by clutch is depend upon the
coefficient of friction utch
plate (R). () of the material and radius Or C

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Automobile Engineering (MSBTE Sem-Vi 2-3 Automobile Transmissión Systems

2.1.4 Functions of Clutch:

MSBTES-16
QRStatepurpose and funclion of clutch in automobile, S-16

To permit engagement or disengagement of a gear whien the vehicle is stationary and the engine is running
2. To transmit the engine power to the road wheel smoothly without shocks to the transmission system while
setting the
vehicle in motion.

3. To permit the engaging of the gear when the vehicle

is in motion without damping the gear wheel.
2.1.5. Design Consideration of friction clutch:
1) The suitable máterial foming the contact surfaces should
be selected.
2) The moving parts of the clutch should
have low weight in order to minimize the inertia load, especially high speed
in
service
3) The clutch should not require any external force to maintain contact
of the frictional surface.
4 The clutch should have provisionfor facilitating repair
5) The ciutch should have provision for carrying away thie heat generated at
contact surfaces.
6) The provision for taking up wear of contact surface must be provided.

2.1.6 Selection of Clutch

The factors taken into consideration fordeciding type'
of clutci are listed belowi:
1)Torque: Required normal force, type of friction surfaces and number of surfaces
2). Rotation speed :t should be light, compact and intemally balanced
:
Available space Diamèter and height of clutch.
4) Frequency of operation: Type of joúrmey.as small travel, a simple engaging mechanisn, large cooling area, low
inertia.

2.2 Classification of Clutch

MSBTE:S-15
sific
te tne casSiicaton oincion Cucnes
Clutch

Positive tlutch Gradual engagement clutch

dog.clutch ar spline dutc
(in and out ype)

Electro magnetic Vacuum Hyraulic Fricion Fluid cutch or

clutch dutch clutth lutch Fuid tyowtreel dutch

Cona clutch Disc or plate clutch Semicerntfifugal Diaphram or Centriugal

cutch Coicar clutch
spring citch

Intermal Extemal Single plate Muld plate

Taper finiger Crow sping
Cone Cone CIuch. clutch type
type

Dry clutch Wet ctutch

Fig. C2.1
Techiaveledi
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 Engineering (MSBTE Sem-VI) 2-4 Automobile Transmissi
Automobile
Syste
2.2.1 Single Plate Clutch
MSBTE:S-16,W-16.
S.7
QDraw neat labelled sketch of single plate coil spring clutch of automóbile.

Q: Draw aneat labelled skelch of single plate clutch:

Q.Descnibe with neat sketch single plate cutchi

Q Explain the necessity and working ot single plate clutct with neat sket

Construction:

The part of single plate clutch shown in Fig 2.2.1.

It consist of flywheel, pressure plate, clutch plate with friction lining'faces called friction plate,
cutch pedal,
ball bearingamdclutch springs.
thas only one chutch plate, mounted on the hub which is splined internally and free to slides overthe clutch
th.
ust
n
sha
Fywheel is mounted on the crankshaft and rotates with
it.
The pressure plate is fixed to the flywheel through clutch
spring by means of þolts.
The springs are arranged circumferentially
to provide axia foreon pressute plate to keep the clutch in engage
as shown in Fig. 221 (a). posi

Thefriction plate held between flywheel and pressure plate having iiction facing on both side
to provide two z
friction surfaces for power transmission.

AAMAGS

Lautthpadai

Flywhee-

Fulcrum pn

Clutch sha
Engine shat

Bearing

Pressure plate

Cutch plate

AiAI Fiction ining

Cludch spring

Fig. 2.2.1a):
Single plate clutch

Td
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 Automobile Engineering (MSBTE_Sem-V) 2-5 Automobile Transmission
Systems

Working of Single Plate Clutch

hen hatch pedal is pressed the pressure plate iS moved to the nght (from Fig. 2.2.1 (a)) against the spring force and
this is achieved by means
of suitable imkage (not shown in Fig. 2.2.1a)) and thrust bearing.
Pressure plate

Fywheel

w Release lever
-Release
fever plate

Clutch shaft

ww
Cover
a
Fig. 2.2.1b): Simplifed diagrarh howing the working of singte plate clutch

Due to this movement of the pressure plate, the friction plate is releasod and clutch is disengaged and when pedal is
released tie pressure plate moves to left (from Fig 2.2.16)) due to clutch spring arranged circumferentially and thus
clutch again engaged
Advantages of Single Plate Clutch:
1. Gear changing is easicr than the cone elhutch because the pedal movement is less.
2 Itis more reliable because it does not suffcr from disadvantage of binding of cone.
Disadvantage of Sfnigfe Plate Ctutch:

The springs have to be more stiff kience greater force required by the driver for disengaged
Applicatton of Singte Piate Ctutch

This clutch is used in four wheelers like Truck, Jeep Fiat-1100, Ashok Leyland, Tata sierra etc.

Clutch
2.3 Diaphragim
MSBTE: W-17, W18.S19

GExplan wilh near sketch, the working ot a W17

ODraw.neat sketches for diaphragmspring type clutch in engage and disengage position Name the componerts 18)
construction and working of iaphragm ypepr clutch
aExplan S-19
In this clutch, in order to produce the required pressure for engaging it, a form of diaphragm or conical spring is
employed in place of coil springE

This type of clutch is quite advantageous because and the spring itself acts as a series of
itrequies no release leve
levers.

Some of the conical springs used even are not having the constant-rate characteristics.
.The presure of spring is always varying
this position.
It increases till the spring reaches to its flat positionm and decreases with the passing of
TerhKavaedg
ttiess
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 Automobile Transmission
2-6 Systems
Automobilo Engineering (MSBTE Sem-V)_
out of engagement as in en:
high a pedal pressure to hold the clutch case
In case of this clutch, the driver has not to cxert as
of a coil spring type.
to disengage the clutch, the spring pressure funb
In casc of a coil spring type of clutch, when the pedal is depressed arther
increases.
tapered finger type of diaphragm spring operating in a clutch
assembly.
In ig. 2.3.1 is shown in the
Flywheel Flywheel

Pressure plate assembly This section ofspring

moves back.
Rim

Rear plvot ring Pivot ting

Pressure plate

Dlaphragm spring This section ofspring

moves forward

Throwout bearing

Cover
Clutch plate Pivot ring
Pressure plate
Engaged Clutch plate
Disengaged.
Fig.23.1:Dlaphragm Clutch Operation
The spring is pivoting on the rear pivot rings
in its engaged position while holding itself
on the clutch cover.
In this position the pressure plate is
in contact with its outer rim. Therefore,
making a fim contact between the pressure sufficient pressure is exerted
plate'and clutch píate as well the
by the spring
as flywheel in this naturaconícal positiot
Now inorderto disengage the clutch,the pedal is depressed
The throughout bearing is moved toward the flywheel the
by linkage due to pedal depression.
As the spring is pivoting on thefront pivat ring therefore,
moves that portion the bearingcontactingthe
forward resulting the rim to inner portion of the conical spring
move backward.
The clutch disc gets released from
the contact with both
the driving members because
is removed the pressure pressure on the pla
The release levers would move towards the withdräwn
bearing,and.prevent
wearing down of the friction lining. the clutch from engaging füly due
To prevent the clutch slipping,
a free movement of about
bearing is provided 25 mm at the clutch pedal
or 1.5 mm at the
winr
2.3.1 Difference between Coil Spring
and Diaphragm Spring
Type Clutch:
MSBTE: W-
Diferentiate betweencoilspring
gAgM.cutch, fay four
STNo Coil sprina
Col spring clutch
Helical compression Diaphragmspring clutch
coi spring is used. Diaphragm conical spring is
used.
2 Release levers requires.
No release levers.
Non-unifomm pressure or on pressure
plate. Uniform pressure on pressure
plate.

TId

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 Engineering (MSBTE Sem-V) 2-7 Automobile Transmission Systems
Automobile

Sr.No. Coilspring chitch Diaphragm spring cliich

cffort for disengagement| Driver required less effort to disengagement of clutch.
Divcr required more
of clutch.
pressure constant.
During disengagement spring pressure.increase.| During disengagement spring
5.
Requircd more space. Compact in size required less space.
6.
Balancing is simple.
Balancing is complicated.

2.3.2 Multi-plate Clutch

MSSTE:S-15

Describe the working.of muit-plate dry clutch win

diagram, State.its.applications. S15
frictional plate (friction surface and clutch
single plate type clutch where increase the number of
t is a modification of
plate).
clutcht increased, the size remaining fixed:
this friction surface increasing, the torque transmission capacity of
Due to clutch.
rëduced for same power transmission as a single plate
Altematively the size of the clutch is
transport vehicles and racing cars where high torque transmited.
This type of clutch is used in heavy
limited.
This clutch is also used in scooter
and motor cycle as space available is

A systematic sketch of
multi-plate clutch is shown in Fig. 2.3.2(a).
- Flywhees Clutch pedal

Fulcrum pin
Pressure
plate

Spigotend

2ZZZZTTAE
-Springi
Bearing
Clutc shaf-
Friction Tiring
Clutch plates

(a)Multi-plateclutch

0 Plates with outer teeth (i) Plates with inner teeth

(b) Friction plates mult-plate
of clutch
Fig. 2.3.2: Multi-plate Clutch
rhknouledgi
Pbatlens

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 Automobile Transmission Systems
Automobile Engineering (MSBTE Sem-V)_ 2-8
two sets of
bearing and ciurcn pedal and
spigot.end with clutch spring, thrust
ot. 1lywheel, pressure plate,
Cnsist
Triction plate.
on splines on the pressue plate
flywheel and other one slides
One. set of friction plate slides in longitudinal
groove of
hub.

The friction plates are arranged altematively to each set:

pressure plate to move right (Grom
axial pressure acts on the
pressed, the
when the clutch pedal is
Fig. 232) and compressing the clutch spring at the spigot end.
disengaged.
Thus pressure on friction plate released and it is pressure plate to left
pressure plate to moves ihe
spring exert a pressure on the
When clotch pedal released the clutch
(fromFig. 2.32) and thus clatch again engaged
Number of pairs of contact surface= (n-1).
t'n'isthe number of friction plate in multi- plate clutch
Torgue transmitted by chutch = T=(n-1) 4WR.

Advantages of Mult-plate Ciutch:

1. Increase the amount of torque to be trinsmitted.

2 Decrease the pedal effort to operate the clutch.

3. Decrease the weight of the clutch.

4. Decrease the M.O.I. (Moment of Inertia) of the clutch.

5. Increase in better acccleration.

Disadvantages ot Mut plate Clutch:

t More number of friction plate

2. large anount of heat developed which may changes the properties of friction lining
3. Heavy

4. Too expensive
Applications of Muti-plate Clutch

1. Sport car, motor cycle

2. Heavy vehicle

3. Locomotives

Difference between single plate clutch and multi-plate

clutch:
SeNa Single Plate Cutch
Multi-plate clutch
Only one frction plate
Two sets of friction
plates (More than one)
2. Power transImission capacity
is more. Power transmission capacity
Iess.
3. Size is large
Size is small or compact

4 Springs are arranged círcumferentially.

| Only one spring located on spigot end
centrauy
2.3.3 Semi Centrifugal Clutch;

In this type of clutch light clutch spring

of sufficient strength
exering low pressure at iclingspeeds are
Also the pressure between the friction used.
plate is increased with
to the pressurerequirements the increase of speed
by means of centrifugal of rotation of the clutch in prop
weight attached to the
hinged lever at equal interval.
Trdi
featin

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 Automobile Engineering (MSBTE_Sem-VI) -9 Automobile Transmission Systems

The pressure plate moves towards the flywhecl and, the ends of the relcase lever
are moves back against
the throw out
bearing by the action of centrifugal forco which increase by increase in speed of rotation.

The clutch spring pressure exert low presSure at the idling speed can be used by this set. for facilitating the depression
of
the clutch pedal for shifting gear.

As the speed of rotation increase, the rotating weight tends 1o move the pressure plate toward the flywheel
(to the left
from Fig. 2.3.3).

.The ends of release levers are also moved back against the throw out
bearing along with this movement of
the pressure
plate.

Ring gear
Thrust spring
Fly wheel
Pressure plate
Custion spring-
Centrifugal
-
Clutch plate hub (Splined) forca
-Release finger

Spring
Cover force
Chutch plate
Speed
(a) Plate
b) Speed
Fig. 2.3.3:Semi-centrifugal clutch
2.3.4 Centrifugal clutch

The centrifugal clutch is extensively

used in light two wheçlers
like moped or two wheelers without gear.
The centrifugal clutcb, uses centrifugal
force, instead of spring force
Tequire clutch pedal for keeping it in cogaged position,
för operating a clutch it does not
Theclutch is operated automatically
depend.upon the engine speect.
Thevehicle can be stop in
gear withoutstalling theengine.and driver
can started a vehicle selecting any gear.
Fig.23.4 a
Shows centrifugal clutch.

Clutch shaft
Engine shat

Flg.234:Centrifugal cluteh
t consist of lywheel, pressure plate, friction plate, spring, cover with stopper and
bell crank lever.
As the accelerator pedal is pressed, the engine speed increases. Theweight A attached to one end of bell crank lever
uCs upward exerting a pressure on pressure plate C, so the pressure plate moves towards teft (from Fig. 23.4) which
increases the spring force
E.
FciKaeuledgi
Puhlicatlons

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 2-10 Automobile Transmission
Automobilo Engincering (MSBTE Sem-V) Systems

This increase spring force (through the spring E) cxert on the friction plate D pressed against the flywheel
el E, ther
E, thereby
cngaging the clutch.
As the accelerator pedal is relcased, the cngine specd decreases. The weight A attached to bell crank
crank lever
levee moves
downward. So the force exerting on pressure plate C decreases and clutch comes to disengaged
position.
The spring G serve to keep the clutch disengaged at low speed by spring force Q. H is the stopper
for limit the
of centrifugal force. the amount
.

Difference between Semi Centrifugal Clutch and Centrifugal Clutch

S Semi Centrilügal Clutch

entritugal Clutch
| Light clutch coil spring of suficient strength
is used for| The centrifugal clutch
exerting low pressure idling uses centrifugal
at speeds are used and
hinged|instead of spring force for keeping
foroe,
fulcrum lever with weight at equal interval it in engased
which provide | position. gaged
centrifugal force for engaged the clutch.

2. The clutch pedal is not required

to operate the clutch.
The clutch pedal is not require
operated automatically
or The clutch is
depends upon the
spced. engine
2.4 Types ofTransmission Systems
There are broadly classified
in two types :

Type of transmission systems

1) Standard or manual
transmission (Stick.shift)

2) Semiaatomatic transmission
(Automated manual
Uansmission)
3) Fully automatic
Transmission

Ha. Hydramatic drive.

Hb.Controlled-coupling
hydramatic transmissions.

c. Three-speed hydramatic transnissions.

4) Continuously variable
transmissian

5) Dual-clutch transmission

Fig.C2.2:Types
1) of Transmission.Systems
Standard or manual
transmission (Stick
shift)
Driver can sclect all the
gear manually both
a movable gear selector
2) Semi automatic transmission and a driver operated clutch
(Automated
manual transmission)
The action of clutch is not
controlled by driver
direct shift gearbox. Only the but automated using
clutch is operated pneumaic or hydrauic
gear are changed automatically automatically,
by control mechanism the driver has to select the gears. In
which is actuaté by the accelerator
peca
Tedh

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 Automobile Engineering (MSBTE Sem-VI) 2-11
Automobile
Transm
transmission Systems
3) Fully automatic

There are two pedal i.c. for braking and for accelerating. Also an a selector mechanism
The following three different types of fully automatic transmission are in us
.
a. Hydramatic drive.

b. Controled-coupling hydramatic transmissions.

c. Three-speed hydramatic transmissions.

4) Continuously variable transmission

The transmission has continuously variable drive ratio

and uses belt, puileys and sensors
steady acceleration curve with no pause of gear rather than gearto maintain
change keeping constant power
range and inçrease
efficiency.
5) Dual-clutch transmission

2.5 Function and Necessity of Gear

Box

MSBTE:S-14, W-14.
QExplain the necessity of Gearbox in W-17
Automobiles
aStatethe nécessity bf transmissionsystemin
An Internal combustion engine
a
4W4
produces little power
at low speed and maximum power
the particular engine. at a gven specd depending
on

The gear box has a series

The automobile required high

.
Whenitdirectly coupled with gear box, a fixed roadspeed
ofgears and shaft to vary the
is provided to the vehicle
speed ofthe gear box output
shaft comparedto the engine
torque, when climbing speed.
speed. hils and when starting even- though
they are performed at low
On the other hand, when
runing at high speed on the straight
momentum and would level road, high torque is
t be more preferable to have
just thewheelalone turning at high speed.
not required because of
However, the torque which
the engine can produce is
torque necessary limited to such an amount that
for starting and for climbing the engine by itself cannot develop
hil..
The transmission acts
in accordance with the running condition.
When driving power is
required, it reduces
high running speed
the engine speed and transmitsstrongertorque
is desired, it transmits tò the driving road wheel and
high speed low-torque to the wbeels.

Power
available throtie
at.wheels goar-tul
road
Top level
vehicle

Powerof Maximum possible

road speed

Road speed kmhr

Fig. 2.5.1:Road speed km/hr

TedTnomledg
Pablicatias

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 Automobile Iransmission
Systems
Automoble Engineering (MSBTE Sem- 2-12
since cngine can nun in
one directiqn.
t&us0 serves to reverse the vehicle
position, without stopping the engine.
t also helps to kecp the vehicle in neutral speed, fuel economy, noise
Je
acceleration, ability to go up a slope, top
on
he vehicle perfomance is based to provide maximum acceleration at low speed by keeping the driving wbeel wheel
torque ng
durability. The gear box is designed

Output at the point of impending whel spi,

with-cube of speed When the power available matched with.power
The power required to drive the vehicle increases
roquired the ehicle moves forwand at constant speed.

2.6 Types of Gear Box

The gear box in automobile vehicle are classified are as followis:

Types of Gear Box

a) Selective gear transmigsion

1) Slicing mesh fype

2) Constant mesh type

3) Synchromesh type

9Three speed gear box

Four speed gear box

) Six speed gear box .

b) Planetary gear Transmission

1) Epi-cyclic gear type

2) Automatic
transmission

H0 Fluid type or Torque

converter

()Electic type
Twin topgear box

d)Pre-selective
gearbox

2.6.1 Fig.C2.3:7ypes
Constant Mesh of Gear Box
Gear Box

G Draw neat
labelled
sketchof
constar
Q Explanwithneat mesh gear
boxand explain MSBTE: S-16, S-17. W1
sketch wOrking working.
ot constant mesh
In this type of gear
box, all the
gear
box 19
gears on
The.twodog clutches the main shaft,
lay shaft are 17,N
are provided in constantlymeshing.
first gear and on main shaft,
reverse gear. one between
the clutch gear
and the second
gear andother etwcn
o

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Automobile
Engineering
(MSBTE
Sem-VI) 2-13 Automobile Transmission Systems
The main shaft
is splincd and
all the gear on
The two dogclutch
can slide on
the main shaft arc free to
rotatc.
the main shaft and
All the gear on lay
also as same
shaft (counter
rotate with
shaft) are rigidly fixcd
it
as enginc ty
spccd., fixcd with
with it and onc
onc gear on 14y
lay shaft is mesh with clutch shart geat

with tecth o
eth on OW gear) the Dog
low gear M clutch D, moves
toward by mean of gear shift lever,
it teeth arc engg
Gg
direction 1s moved
right (from
of rotation Fig. 2.6.1) and
is changeby gear L. mesh with teeth on M,
gear, a reverse gear is
00lau Ihe

Secondgear- LOw gear

Clutch gear Reyersa gear

Engime
shaf

Main shat

- Intemediate gear

Lay shaft

Fig. 2.6.1:Constant
mesh gear box
Second gear
Gear

Clutch gear- Reverse gear

i
Engine shaft
Main shat
Intermediate gear

Lay shaft

Fig. 2.6.2: Power flow diagram in first (Low) gear

Tehkaeuledge
9biltatians
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 2-14
ionSystema
Automobile Iransmission s
Automobile Engineering (MSBTE Sem-V)
Second gear
Reverse gear

Clutch pear

Main shaft
Engine shafl
Irntermediate gear

Lay shaft
B

in second gear
Fig. 26.3: Power flow diagram
Second gear-
Reverse gear

Clutch gear

Engine shat Main shat

-Intermediate gear

Layshat

Fig. 2.6.4:Power flow diagram in direct gear

Second gear Gear
Reverse gear
Clutch gear

-
Engine shaft-
Main shat
Intermediate gear

Layshaft

Fig. 2.6.5 Powerflow diagram

in reverse gear

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 rww
3"***w
toward right which mesh withthe
tch ID, is moves
dog clutch
hand scond gear
When left dogclutch D, movestoward left
ohtaining tthe direct gear by sclector (M,y.as
obtained for obtaincd. l cchanism
diræct gear is to meshwith
gear K, a teet
teth
on clutch a nstant mesh, they
box, hecause of are safe from
gear beingdamage
In this wihiiec.cngage and discngaged. and unpleasant
sound does not
occr ginding
follows:
power transmission is as
The
gear A
Clutch gearK-lay shaft -lay shaftgear Main shaft pear
Low gear: M, -dogD,-Main
o shan for
final dive
gear::Clutch gear K-gear A - gear gear M, -dog D,-Main shaft
Second forfinaldrive.
o
gear K- Dog D, ~main shaft for final drive
oTop gear: Ciutch
Intermediate
oReverse gear: Clhtch gear K- gear A-gear D- gear I-gear M, - Dog
Dg-Main shaft for
final dive.
skillful anding is necessary by drive so that speed
this gear box a of locking dogs and respectve
In effect a clash free gear change. gear on main shaft
remains ne to For obtaining same speed double declutching
is necessay.
Double Declutching

MSBTE: S-16,W-18

OEXpain needotdouble declutching

Rlain the concept.ot.couble .ectchng ralated to constant mesngeart

18)
gear bOx, 1or smooth engagement of the dog clutch, must be necessary keep
In constant mesh it to the speed of dog
clutch and gear on main shaft,must be equal.

For obtaining low gear, the speed of the ciutch shaft, main shaft and lay shaft gear must be increase and this is doneby
doubledeclutching..
First main chutch is disengaged and the gear are braught to
neutral position then engaged the chutch and press
gear then disengaged the cluteh and dog clutch moves to
accelerator pedal for increase the speed of the main shaft
required lower gear and engaged:

Thenclutch again emgagedi

hence it is called cdouble declutching.
this process clutch is disengaged twice
Asin dfiver has to wáait with the gear in
neutral il the main shaft speed is decrease
sufcienty
For obtaining higher gear the
for smooth engagement of the gear.

Advantages
gears are in constant nesh.
jts.operation, asall.the
gears are easier and quite in So we can have a
smooth and
Tnese having a smaller
diameter than the gear it controls.
mesh is
Z.he cutch used in constant
discngagement involved.
easy engagement and the dog clutches are
disengaging decreases
because althe teth of
duringengaging and same size.
Wear of dog teeth torque transmission
capacity than
ordinary gear of
the toeth of the gear wheels
Helical gear has high teeth and not to
4. occurs to the dog clutch
fauliy manipulation
damage that resuits from
.Any even ioss of
mechanical components and
Disadvantages damage lo
inappropriategear by mistake,
an
inexperienceddriver sélects
f an
control may occur.
TedKaeufedge
Blatlo

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 2-16
Automobile Engineering (MSBTE
Sem- MSBTE:W14 War
2.6.2 Synchromesh Gear Box -14, W-15is
operar
synchromesh
gearbox.
gearn cvery type of
by syne
RExplain with neal sketch, wokingof can be done types of nchromesh
so that lhis diterent
changing gear consequent damage, gaa
In order to sinmplifty lhe operalion of
the opertion and their
uy occumence or teeth clashes
wiuhout occurence
of
unskilled driver without and gearbbox output
shaft
chicle.
vehic engine driven
devic
evices are uscd in different type of motor
the speeds of
both the
clutches or equiva
ivalent meshin i
is to bring their dog unit
moving
a these
But the principle off all
devics
rotational speed
for i
gear which are to becngaged
eng to the same
shaft are im
constant.mesh
engagement readily and quietly. gear on main shaft, lay
box that the
similarwith constant
miesh gear
rotate as lay
shaft gear speed.
uS gcar box is
Th
gearon main shaft are
free to
fixed while friction after which
which these
t m
nc gear on lay shaft are
by
cqualises the spccdby
instead of dog, which
devicc is used
In this a 'synchromesh
having clutch gear B rotate
engaged smothly. the engine shaft T.
The systematic skeltch of
synchromesh is shown in Fig. 266.A
is
gear on lay . isthe
shaft. U. is th
a
on main shaft
and gear U,, U, U, and U, are the intermedi
speed, gear B, C D,E are
**

shaft which is spline internally.

gcar.
synchromesh member free to slide
on main
F and F,are the
teeth which fit onto extermal teeth of member F, andn
shape member having intemal
G, and G,are the ring
,
L and are dog teth on gear B, CD, E, T, and T, are
the ball supported by spring. S, amd S,are the fork

obtained low gear member F,

moves toward left (from Fig. 2.6.6) which causes the friction contact betwe
To thecoze
shape surface of gear D and member F

or
This ficion rubing makes the speod qual then member G, overide to left to engage with teeth K, and In
obiained., Similarly when member E, slides toyard igh, mesh with gear E, a everse gear is abtained.

Similarly for second gear the member F, and G, are slid to the ight so that finally the intemal teeth
withL, then the drive to main shaft from gear B-
on G. are
a engaed
U,-U gear C-G,-F,to spline.

Clutch shat

Main
shait

Fig.2.6.6(a):
Neutral
positilon

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 Automobile Engineering (MSBTE_ Sem-VI)
2-17
Automobile Transmission Systems
A direct gear is dbtained by sliding member P, toward left.

A synchronizer ring is provided betwecn the dog teeth K, and member F,

To push this ring in the proper direction, three guide bar are cqually spaced
along the circumference are provided. These
are retain in the placed by means of circlips.

This ring has dog teeth at its outer círcumíerence and is cut at three places
to provide space for guide bar.
.The widtt of each cut is equal to the width of the guide bar plus half
the pitch of the teeth of the symchronizer ring.
The synchronizer ring help to ovemide the ring gear when speed of member and gear is equalize and hence ring gear
moves to engage the required gear ratio.

(b)Direct gear position.

gear
Fig. 2.6.6:Syhchromesh box

Power Flow diagram:

Fig. 2.6.7: Power flow in first (Low) gear

A- Gear B-UU- Gear D- KzGFar Final drive

TechKnvulelgi
u tiins

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Automobile Automobile \ransmissiorn
Enginocring 2-18
Engineeting (MSBTE_ Sem-V
(MSD

GI

Fig.2.6.8:Power flow in second gear

Gear B-U-Ua-Ly-S Member
F-Final drve

S2

Fig. 2.6.9:Power flow

in reverse gear
Shaft A-Gear B-U-U-Us-Reversegear
E- Gear G2-Member F2- Final drive
Direct gear posiion
is shown in Fig. 2.6.66) of Synchromesh
gear box.
Advantages of Synchromesh
Gear Box:
1. Power tansmissioncapacity
in synchromeshgear box
is more as compare to Constant
2. Changing gear can be done MeshGear Bon.
by every type of operator,
their consequent damage. skilledor unskilled driver
withoutoccunence of ten
3. Noneed of double declutching.
Disadvantages of Synchromesh
Gear Box
1. Gear box is more expensive

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 Automobile Engineering (MSBTE Sem-V)
2-19 Automobile Transmission
Systerms
2. It is more bulky due to additional component.

Common features in a constant mesh and synchromesh gear

box
. All the gcars on the main shaft, lay shaft are in constantly meshing

2. The main shaft is splined and all the gear on the main shaft is free to rotate.

3 All the gear on. lay shaft (counter shaft) are rigidly fixed with it and one gear on lay shaft is mesh with clutch shaft gear

also as same as engine specd.

4 Gears on main shaft are fitted on bearings.

5 Synchromesh device and dog clutches are fitted, one between the clutch gear and the second gear and other between
first gear and reverse gear.

Differences in a constant mesh and synchromesh gear box

which these
in synchromesh gear box a two synchromesh devices are used which equalizes the speed by friction after
the speed
may be engaged smoothy. While fn a constant mesh two dog clutches are used which equalzes
mesh operation of double declutching is
2 In synchromesh gear box no need of double declutching while in a constant
necessary.
unskilled
gear this can be done by every type of operator, skilled or
3. In synchromesh gear box the operation of changing
driver without occurrence of teeth clashes and their consequent damage.
nubbing.surface, ball and spring and'a. synchronizer ring
having few teeth
4. Synchromesh device consist of cone shape
while a constant mesh dog clutch is provided with few teeth.
in

synchromesh gear box is more as

ompare to Constant Mesh Gear Box.
5. Power transmission capacity in
dog teeth which helps meshing of
gear box, the main shaft geai pròvided with two type of teeth one is
6. In synchromesh
lay shaft which received power from input
final drive and other mesh with gear on
gear and for power transmission to
shaft:
manual transmssion)
Semiautomatic transmission (Automated
2.7
the car handles manipulation
control also allowed for a sort of cross-breed transmission where
The creation of computer "clutchless
manualy if desired. This is sometimes called a
clatch automatically, but the driver can still select the gear
of the the driver to give full controt to the
"automated manual" transmission. Many of these transmissions alow
manual" or passenger,cars, have
mamual transmission "intermals", and when used in
computer. They are generally desigied using
gear sets.
synchromesh operated helical constant mesh
Easytronic, and Gartronic.
Specific type of this transmission includes:
used, each with its own clatch, so that
anly
sets of intermals which are aternately
A "dual-clutch" transmission uses two
the clotches are used doring the actual "gear
change"
Direct-Shift Gearbox..
Specifie type of this transmission includes :
switch gears.
which use the rotation of a drum to
There are also sequential transmissions
clutch. Torque converter is also
transmission is a combination of fluid coupling and a conventional
The semi automatic
automatic transmission was introdiuce in
models of semi automatic transmission. Chrysler semi
used in late some from the vacuum unit of the
In the first model, the power for shifting gear is obtained
1941by the Chrysler corporation. operate the automatic
by using hydraulic pressure from transmission gear pump to
engine manifold. Then it improves

shaft TeKnealedgu
Dtatlons
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 Autornobile Transmi
smission
2-20 Syse
Automobile Engineering (MSBTE Som-V
Direct-speed
dlutch sleeve Third speed gear
gear
Clutch D, First speed
Reversa gear
teeth
Main drive pinion

N Main shat
Clutch
cdutch
shaft E, Manual
sleeve

Counter shaf
cluster
drive gear B, Countersthaft gear
Free-wheling
unit
transmission power flow (Neutral)
Fig. 2.7.1:Semiautomatic
transmissiom
speed Chrysler semi automatic .Thech
2.7.1 shows arangement of
three forward and one reverse
Fig lay-shaft as in conventiana
the main driving gears which ther turn gear on nal ype
shaft is driven by engine and rotates
by one-way clutch or freewheelin
cluster is not integral with the lay-shaft gear, but driven ngunit.
lay-shaft gear
The (counter shaft) gear and
respectively are in constantly with their lay-shaft
The third and fist speed gear C and D
freely on the main shaft in neutral position.
contact with the dog clutch teei
The manual clutch sleeve Eis spline on the main šhaft and máke synchronized
mechanism lever.
gear Cand gear D when operated by the selector

The direct speed clutch sleeve Fis connected to the third speed gear C through.aspline and can engaged the clutch
tbe
of the main drive gear when moved' by the fork of the power unit
The power flow is shown by the arrows in Fig. 2.7.

2.3 Overdrive

MSBTE WSE W10

aDescribe the workingot bverdnive with neat sketch

W16,W-13
This is a device helps the propeller shaft to rotate
faster than the engine in the transmission.
Byemploying this engine speed can be reduce by 20 to 25% allowing
high crushing at low engine speed.
So advamtage of this is increase
to engine life, improve fuel consumption,
also reducenoise and vibration. increase
gear ratio available by fiting
it to intermediate gear. It
Itis generallyfittedon top gear.

It also fited on gear other

than top gear which
increase torque ratio.
e.g. in sports car.
It can be operated automatically
or manually.
It come into operation
at a particular speed
when operate automatically.
2.8.1 Construction
and Working of an
Overdrive
It consists of
an epicyclic
while the camier gear train in which
can be slide. sum gear is free
A free clutch to rotate on the
output shaft.
is also fitted on engine sshaft (input shaft) which is sp
input shaft. The
When the ring gear is mesh
sun gear is locked wiun un
Overdrive with the casingie.
is engaged. it became stationary,
the speed of the output cæ say s
shaft
incre
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 Automobile Engineering (MSETE_Sem-V). Automobile Transmission Systems
2-21
.When the sun gear is locked with the cafrier or the ring gcar, solid drive through the gear train is obtained.

Planel gear or -Freewheel

ring gear clutch

Sun
gear Output shaft
Input
shaft

Carier

Casing

TTTIIIL
Fig.2.8.1: An Overdrive
Thus depending upon the locking of sun gear with casing 'or carrier the overdive or direct drive is obtained.

.There is amother possible control of the mechanism there is a direcr drive through the free wheel clutch when the engine
develops the power.

When the accelerator pedal is brought to zero positioo and engine is iding, the output shaft wll tends to override the
input shaft.
The rollers of free wheel no longer remain wedge amd the vehicle frewheeis.
Thus for gear changing driver has to lift his foot off the accelerator pedal, clutch need not be aperated:
Advantages of Overdrive

1) lgives higher top gear ratio for better fucl conomy.

2) treduce engine wear and teair because of diven road speed, the engine speed is less,
3) Itis easy forengagement and disengagcment.
4) Aquarter running is provided by reduced engine speed
5) Less physical and mental fatigue on driver

6No shocks and jerks during driving-

7) Noiseless gear shifting.

2.9 Fluid Flywheel

2.9.1 Fluld flywheel or fluid coupling or fluid clutch

fiuid flywhee is mostly used in antomatic transmission system. It consist of two members the diving and tie
The
driven member. The two members are coupled through a fluid media. The driving member is fixed to engine flywhee
and driven member to transmission shaft. The two members do not have any direct contact with each other. The driven
member (runner) is free to slide on splines of the transmission shaft. The.two members are kept in an oil tight housing
which keep oil of suitable- viscosity up to a certain level. Both the members provided with radial rib in their facing
which face toward each other.

AS engine started, the driving member (impeller) beings to move inside the housing containing oil. Due to centrifugal
1orce the blade or ribs forces the oil outward radically. As the speed increases the centrifugal force the oil outward

raly as the speed increases the centrifugal forces increáses and the oil strikes the blades of the driven member and
between the both
along the same direction as a single unit. As engine speed decreases the oil filn
Ove
members is broken and the members are disengaged.

Techrouledgë
PuDItlons

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 Automobile 1ranstmiSSIon Syste
Automobile Engineering (MSBTE Sem-V)_ 2-22
Filler plug

(Impeller
Diver
-Runner

Bearing
Engine shat-

LGearbox shaft
Bearing

Casing

Drain plug
Fig. 29.1: Fluid Coupling

2.9.2 Advantages of Fluid Flywheel:

) No wear of moving parts.

2) Noadjustment is made. The fluid in the coupling acts as cushioning agent between the engine and gear box.
3) Simple in design and it gives smooth power îransmission than centrifugal
type clutch.
4) The impeller acts as a fiywhecl on the crankshaft so smooth torque variation effect.

5) No maintenance is required except oil change.

6) Noneedof skill operator. As no separate clutch pedal

or level is required to operate it.
7) Can be stop in any gear and move off by pressing
accelerator pedal
8) Itgives smoth power transmissiont than
centrifugal type clutch.
9) The fluid in the coupling acts as cushioning
agent between the engine and gear
box.
10) No separate clutch pedal
or level is required to óperate it.
11) The impeller acts
as a flywheel on the crankshaft
so smooth torque variation effect.
2.9.3 Disadvantages of FIuid
Flywheel:
1. Chances of oil leakage.

2. There is a drag on the gear ditica

box shaft even
when the percentage slip 100%. the gear changing
with a ordinary crash is This makesu
type gear box. Hence
it is used with epi-cyclic type gear
box.

TechMopa
Popfitat

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 Automobile Engineering (MSBTE Sem- V) Automobile Transmission Systems
2-23
2.9.4 Characteristic of Fluid Flywheel

Let NI and N2 are the specd of driving and driven member respectively. The percentage slip is defined as the ratio of
difference of spoed of driving ad driven member to the driving member.(percentage slip=N

100

40

500 1000 1500 2000 2500 3000 pm

Speed

Fig. 29.2: Fuid flywheel characteristics

percentage slip
When percentage slip is 100% then the cluteh is said to be fully engaged and enigine speed increase lf
represent definite loss
falils rapidly beyond which the slip decreases gradually to a small value about 290. As percentage slip
range.
of energy and consequently increase in fuel consumption so the engine should not run with that speed

2.10 Torque Converter

MSBTE: S-12

inckude the use of torque comverters which lock up

Attempts to improv the fuel. efficiency of automatic transmissians
power loss, and overdrive gears. which automatically
beyond.a certain speeds, ar în the higher gear ratios, eliminating
actuate above certain speeds.
make use of the hydrodynamic-effects of the fuid flow, ie. pressure due
Ifthe hydraulic pump and/or hydraulic motor turbine.
to a change in the fluid's momentum as it flows through vanes in a
proximity. The
rotating vanes without seals and are typically placed in close
The pump and motor usualy consist of
means of additional rotating vanes, an effect similar to varying the pitch of a
transmission ratio can be madë to vary by

airplane propeller.
transmissions is, üsed in ahydrodynamic transmission.
The torque converter in móst automotive antomatic
shifting the mechanical gears,
Itwas possible to drive the dynamic.flow transmission without
power
passenger rail vehicles. In this application the advantage of smooth
This type of transmission are used in imany
efficiency caused by turbulence energy losses in the flaid.
delivery may outweigh the reduced
converter is a device which perform a function same as gearbox.
The torque or fluid
spèed in motor vehicle with automatic transmission.
It increases the torque with teduction in

Iis directly coupled to the engine fîlywhel

continuous variations of torque ratio
torque ratio whereas torque converter provide a
Gear box provide fixed or smaller
from lowest to highest between 2:1 or 3: 1

Tech Knouledge
Iatias

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Automobile Engineoring (MSBTE Sem-VI) Automobile
Transmission Systema
2-24
Impeller

Turbine
Stalor
Freewheel

Input
-Out put shaft
shat

Fig.2.10.1 Single stage torque converter

Fig. 2.10.1 shows single stage torque converter mainly consist of three parts,
1) Impeller or the driving member coupled to the engine.

2) The turbine or the driven member which is comnected to road wheel through transmission
system.
3) The stator, ixed to the frame through the freewheel.
Also, there is a transmission oil pump which keeps the converter full of oil under pressure when
rotating.
Due to rotation of engine shaft, centrifugal force develop which pushes the oil in outward
direction and this tends
form air packet near the center of tie converter.

This phenomenon of forming air packet due to low pressure i3 called cavitation so
avoid this converter pressure is kept
between 200 to 1200 kPa.

When the engine start, impeller start rotating thus initially oil from the impeller
is pushed into the turbine becanse of
higher centrifugal force develop at the impeller and the turbine is stationary.
As the oil having high kinetic energy from the engine througlr the impeller
hit at the oater edge of the turbine. This higt
energy flow of oil forces to rotate the turbine.

This force increases with increase of engine speed, when sufficient

force is developed, the turbine start rotating and
vehicle moves.

The turbine blade angle is such that it changes the direction

of oil ffow so that it comes out of the turbine at the cenr
its direction is effectively backward.
To prevent the loss of power, a stator is provided avoid
to the dragging action on the impeller, so the filud mom
turbine'blade is made to strike on stationary member which
changes the direction suitably so that the onl ieaving
stator strike the impeller in favourable direction.

Then the impeller discharges the oil back

into the turbine at the outer edge. This goes on continuouSTY
This repeated pushing of the turbine blade non is
called
causes the torque on the turbine increases. Thms pnen
Torque Muliplication'.
The maximum torque multiplication speed
occur when turbine stationary and impeller
This is called 'STALL'. is is running tast a

echaoul

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 Automobile Engineering (MSBTE Sem-VI)
2-25 Automobile Transmission
Systems
The maximum torque multiplication at stall is about 2.1 to 2.6. When vehicle beings
to move, the hurbine speed starts
to
increase and the torque multiplication gradualy decreases as the difference of speed between
the impeller and turbine
blade.

. Torque multiplication is unity when the impeller and turbine speed is equal
This is known as direct speed.
210.1 Comparison between Fluid Coupling and Torque Converter

No. a. coupiin Yorgue converter

. Power transmits through fluid.
Also power transmits through fluid

2 Automatic device.

Consist of impeller and rumer.

Automatic device.

It consists of pump, stator, impeller and runner.

It only connect driving and driven unit.
It is torque multiplication unit.
S. Impeller and runner are locked up and movement never locked up and flow of oil never stop but
oil stops during engagement when centrifugal force
ofIt
.
is.continues.
approximately same on both member.

Itis efficient at high speed.

6 Itis not efficieat at high speed.
The blades are of fins type. The blades are inclined having pitch.

8 It acts as a only automatic clutch. If acts as a automatic clutch as well as automatic gear
boxfor increase torque.

2.11 Eplcyclic Gear Traln (Box)

MSBTE:S18, W-18
the orKng ol epICYCio gear 5ox wih neat skelch
OEn In the epicyclic or planetary type geartransmission there no
8 W-18)

is dog or sliding memberto engage but different speeds are

obtainedby tightening brake bandon the gear drum.
This is an essential part of the overdrive. This system mainly
consists of three types of gears.
. An outer ring gear having inside teeth which
is called as ring geai.
2 Two or three planet pinion held on, pinion shaft
a in a cage or carier. These planet gears are caried by carrier and
a shaft and are also mesh intemally with a ring gear which
is also called annuus or internál gear sometimes.
.3. A sungear at the centre of the planet gears.
An epicyclic gear box system is shown
in Fig, 2:11.1 shows a sun gear about which planets gear turm round.
All the three members are fastened
to its own shaft. The shaft is supported on a bearing so. that members can tun freely
and hence can receive ortransnit
power.
Any of the three members can drive or driven member
provides one af the other two components is held so nat t
cannot tim. In case none of the member
position.
is
held, the power cannot be transmitted and said that gear is in neurai

TechKnuledge
bcatloas

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 Automobile Transmis
Automobile Engineering (MSBTE Sem-V 2-26
ba
band Syste
Brake band-
Ring gear Braka
& Planet gear

gear
Sun
5

Sun gear
Planet
carrier
shaft

E Planet RE plaet
camer

Fig. 211.1:Simple Epicyclic Gear Box

Operation of Simple Epicyclic Gear Traln:

In order to obtain different specds any one of these three units can be held by rotation by means of brake
band.
brake band is operated by a lever to grip a ring gear and hold its movement. T

The sun gear at the centre- is rotated by the driving shaft frotm the cngine, and thus rotates with the movement
shaft.
tofcret
As the planet pinion are in constantly mesh with both sun gear änd ring gear which are free to rotates
on theirOWD
oun
on carrier which in tum is connected to driven shaft.

When the ring gear is locked by brake band; the rotating sun gear causes to rotate
panet gear. As ring gear is loci
the planet pinions are force to climb over it. At this position ring gear acts as a track
for the planet gears to move One
and thus driven shaft rotate.
When the ring gear is released it is free to move in consequence to
the rotation of planet gear to the rotation of pans
gear which rotate around their axis. At this position, there is
no movement of planet carrier and hence the driven
remains stationary. The operating position depends upon locking member si
of and thus planetary gear acts as
a) Overdrive: The ring gear is locked, sun gear is driven member and
planet carrier as a driving member.
b) Overdrive: Planet carier as a driving member, ring gear driven.
is member and sun gear is locked.
e) Reverse overdrive: Ring gear as a dtiving member and Sun gear
is driven member Planet
caier is locked.
d)Speed reduction: Ring gear as a driving member and planet carier
as a driving member sun gear is locked.
e)Speed reduction: Sun gear as a driving member, planet carrier as
a driven member and ring gear is locked
Reverse: Sun gear as a driving member and ring gear is driven member and
planet gear is free to rotate arvun
axis and Planet carier is locked.

Clutch: Sun gear as a drivingmemberand ringgear is driven member, Planet

carrier is locked. Planet gear
may not be locked.
Epicyclic gears are widely
used in automatic transmission
because,
(1). They are always constantly in mesh
2) Smooth and quick.
(3) Considerable varjation
in gear ratio both forward
and reverse can be ohtained
through it.

Tectlar
YP i

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Autormobile Engineering (MSBTE_Sem-V) 2-27 Automobile Transmission
Systems
Let, T, = Number of teeth on sun gear

Tp Number of effective toeth on arm of planet carrier

The gear ratio of a pair of mating gear wheel with respect to the link carrying the axis of the gears is always
the same
whether hie link carying the axmis is fined or moving.

According to abave principle,

Speed of sun gear with respect to carrier

Gear ratio
Speed of planet gear with respect.to carrier
Reverse gear

Here the planet carier is held stationary the internal gear driven by sun gear to which power is applied.
gear
Reverse gear ratio=ethonthedriven
Teeth of driving gear

Teeth on internalgear
Teeth on sun geár

Applications of epicyclic gear train

) Cars that having automatic transmission.

G) Amy Tanks.

(in Wrist watches/walf ciocks

2.12 Propeller Shaft
Introduction

TtePropeller shalt is a diving shaft for connecting the transmision main of the outgut shaft to the diferential at the
ear axles It also caries the transmission main,or output shaft to the diferential for gotating rear whecis. Now the gear-box
or transmission and the engine are attached or bolited to the vehicle chassis orframe and rise or fall as one piece with it. The
rear axle housing (with wheel or differential) is attached to the frame
MSBTESW14:W16 S-17,W-17. S-18. W-18

Xpatn the necessiy.ofsiding joint anduniyersalont provided in propellec shait W14W 18)
Wite hindtons btunversaljoinand sipjont
16)
propy
ale tupciononiversal and sipjontusedin 17, W17S1)
Necessity of Slding joint

To accommodates change in length due to raad irregularities.

Necessity of Universal Jaint

he universal joint takes care of the variation in the inclination of the propeller shaft during up and down movement of
vehicle.

They also permit the motion to be transmitted from the gear box shaft to the bevel pinion shaft of the differential at all
times irrespective of the inclination of the propeller shaft.

of
hePrOpeller skatt connect the transuission shaft (gear box shaf), fo the bevel pinion shaft
dEfrereritial at the wheel axle is alšo caled as drive shafi
It

efaledgi
7PCtins

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 Automobile Transmission Systems
Automobile Engineering (MSBTE Sem-V) 2-28
2.12.1 Functions of the Propeller Shaft:
MSBTE
-14S16
W-14,S-16)
QState pDpellér.shaftshaft
wheels through the axle shaf
to the differential and them to the aft
uran smits rotary motion of the gear box output shaft
which is varying frequently
It transmits motion at an angle
between gear box and rear axle.
It adjusted the change in length
Propeller Shaft:
2.12.2 Construction and Working of (also called slip joint) .
flexible joint, namely a spline sleeve. t) and
stecl tube or hallow shaft and two type of
is made of
end. mm depending upon the tveof
two universal joint at each ranges from I.5 to 7.5 at
mm and the, thickness
ranges from 50 to 70
The diameter usually
application.
of the same size.
them lighter and stronger than a solid shaft
section makes
Tubular
Ttis also less expensive axle shaft deffected,or.changes its position due to spring
defilection
Don
comes across shock bump, the rar shaft of differential changes
When vehicle transvérsally, hence moving in a
circle so beve pinion es ts
and moves longitudinally and
Joint.
position. This care is taken by universal
propeller shaft during up and down movement of
variation in the inclination of the
The universal joint takes care of the
vehicle.
bevel pinion shaft of the differential at al
permit the motion to be transmitted from the gear box shaft to the
They also
propeller shaft
times irespective of the inclination of the
the rear axle movement.
adjust the length of the propeller shaft when demanded by
The slip joint serve to
and external spline o
sleeve attached to the universal joint at left
The slip joint is formed by the internal splines-on the
propeller shaft
truck and lng
shaft and the pinion shaft. of differeptial, is more as in
When the distance between the transmission.
chassis vehicles.
main propeler
connected to the gear box output shaft and other end to the
One or more intemediate propelier shaft is
SharL
Propeller shaft

Sliding
Universal joint
joint

Fig. 2.12.1:Propeller Shaft

The intermediate propeller shaft is supported in bearing unit fixed to frame.

speed is 0r
This arangement avoid sagging and whirl of propeller shaft at critical whirling speed. The whirling
the square of its length.

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 Automobile Engineering (MSBTE Sem-VI)
2-29 Automobile Transmission
Systems
Function of Universal Joint

Tfniversal joint allows transmission or power and rotary motion at an

angle which varies as a vehicle
encounters a
bump.

Function of Slip Joint

This joint allows variation in length of the propelle shaft when vehicle came across road iregularities.

2.12.3 Types of Propeller Shaft:

Types of Propeller shafts are

Types of
Propeller shaft

1.OpenType

2. Enclosed Type

Fig.c2.4: Types of Propeller shaft

1. The open type

like car is used this type of Propeller shaft.
In heavy commercial vehicle and light vehicle
universal joint one at each end.
Itistubular in cross section and is not enclosed. It is provided with two
sbaft and the other to the driving axle pinion
One of universal joint is attached to the gear-box main shaft or output
shaft
Propeller shaft which is comparatively longer is made up to two portions.
The Solid tube
Sip yoke

Fig. 2.12.2:Open type propeller shaft

2. The enclosed type

This propeller shaft is solid in cross section.

casing by a ball
which rigidly connected to gear box
Generaly it is enclosed in a tubular structure called torque tube
joint or large spherical bearing for resisting the torque reaction.
the
are resisted by this tube. Torque tube is
wnEn brakes are applied, the torque and twisting motion of rear axle casing
prevents the pw1sung
the axle housing and
D the reaction of the drive. A torque tube is a rigid extension of
VEn
of axle on its spring during power transmission to the rear axle.
sRubber element

Fig. 2.12.3: Enclosed propeller shaft

TechKared
llcatisns

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 ionSsets
Automoblle Iransmission
2-30
AutomobleEngineering (MSBTE Sem-v
tibe both at the iront and rea.
bearings inside torque
portedby the roller
This type of propller shaft is support
shaft is qute small.
In certain models of hisbype,
diameterof this propeler only
the
As
Omparcd with the open type,

one universal joint is used. provided at the rear end attached ,

the gear bon.
The sleeve joint is
adjacent to
Is located at the front end
longitudinal movement
pinion shaft to prevent

2.12.4 Whirling of Propeller Shaft:

rotation
does not coincide with
axis of propeller shaft during the
#h.shait
propeler shaft
When the center of gravity of G. from rotational .
This will cause bend the
propeller shaft and further increase
the C. ais a
subjected to centrifugal force. eh.
length of propeller shaft. The speed at which
shaft na
depend upon rotational speed and
shaft failure ocurs. The bending whirling
whirling Ham
rotation became infinite, known as critical or speed.
speed. Hence
with additional deflection of the
shaft from axis of te
avoid failure and violent vibration.
critical speed to
operating speed of shaft is less than

The whirling speed depend on

:

directly proportional to diameter of propeller shaft.

1. Diameter of propeller shaft: Whirling speed is
its length and hence for long chen
2 Length of propeller shaft: Whirling speed is inversely proportional to square of
velhicle shaft is fitted in two or three pieces
support in bearing fixed to frame or extending final dive piniom shat au

housing.

2.13 Final Drive and its Type

Up to the drive axle, the power flows in one straight line. At the dive axle it is diverted at right angles to flow toweat

the wheels. The change in the direction of power flow is obtained by means of final drive. The final drive also provides
fixed speed reduction between the drivë shaft and driven shaft and the driving axles

Final-drive is clasified into two main class.

213.1 Final Drive Classification:

Final drive

Chain type Gear type

Bevel gear type Wom and Hypoid type

Wom wheel
Ype

Straight bevel Spiral bevel Herringbone

gearrhype gear bevel gear

(a) Chain type: This type of final drive

is obsolete in motor cycle, cars and trucks un drive
type, the
nowa days. In thistype,
w
is connected with the gear bax by
means of chains and sprockets.
Now motor cycles are used this type of anv

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 Sem-VI) 2-31
Engineering (MSBTE Automobile Transmission
Systems
Automobile

Fig. 2.13.1

gear and the inal arnve. Ihe ring gear 1s nveted to a differential cage and the final drive
type : It consists of ring
ACear propeller shaft. The power flows from the propeller shaft to the drive axle shaft through drive
connccted with the
is
pinion and ring gear.

Depth Pinion

of mash preload

Crown
Tooth wheel
mesh preload

Fig. 2.13.2

2.13.2 Functions of Final Drive:

The rear axles final drive

) Transmits the drive through

a angle of 90 degrees, and,
cars a final dive ratio of
gearbox ratio. In the case of
ATEvolutions to provide a 'direct top'
functions or nc
AIICly4:lis used. Bevel or worm gears are employed to achieve the various
2.13.3 Construction and Working of Final Drive
forming ne crowa
g. 2.13.3 illustrates the represents two friction cones 'A'
geometry
of a bevel gear layout, which the cenue ul
must coincide with
pinion. For avoidance of slippage and wear, the apex of the pinion
the
of the crown whecl. TecMaunlelgi
atitas

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Automobile Engineering(MSBTE
Sem-V) Automobile TransmissIon System
erms
2-32
The system with incorrectly
positioned pinion causes uncqual peripheral speeds of the crown wheel and pini inion.
STy to mount the gear in the
Itis
corect position so that angle of the bevel is govermed by the gear rato.
Apex

Incorect

gear drive
Fig. 2.13.3: Friction cones representing bevel

2.13.4 Types of Bevel Gear Final Drive:

The main features of the bevel type of gear is illustrated in Fig. 2.13.4. The tapered teeth, generated from the centre,
cent are
machincd on the case-hardened steel gears and then ground together to forma 'mated pair'.
The position of the crown wheel relative to the pinion determines the direction of rotation of the axle shaft. Tf ihs .
eCTown
wheel is fited on the wrong sids, which is possible on some vehicles, then this provides one forward and
several
reverse ratios.

For correct meshing and for setting the clearance between the teeth (backlash), adjusters in the
forms of distance
shims or screwed rings are used. When backlash is too smal, expansion results pieces,
due to heat and wear is hw 1
of lubrication. caused

On the other hand excessive backlash produces slackness

and.noise. Each manutacturer
backlash, but itis generally in the region of 0.15 recommends a suitable
mm for cars and 0.25 mm for heavy vehicles.
fPinion

Crown wheel Straight

bevel
Fig.2.13.4:Straighttooth
bevel gearfinal drive
2134.1 Spiral Bevel

Although the straight

bevel is cheaper
which has been and mechanically
efficient, the meshing
reduced by introducing of the gears causes am uuwad noist
a helical form of tooth.
tis imposible to generate
a helix on a tapered
COnstrucion pinion, so the gear
ofthe gear. A number is called as aspiral bevel. Fig. 2.13.5 illustrals
spiral in the of teeth are generated handed
case of the
pinion. from the centre of the crown
wheel m left
is direction provides
the pinion bearing
alarge outward thrust 'wearaf
increases on the drive and
the backlash a smaller inward thrust o
instead of causing
seizure of the gear.

Tedlsle
7
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RAutomobile Engineering (MSBTE_ Sem-VI) 2-33 Automobile Transmission
Systems

Spiral
bevel

Fig.2.13.5: Spiral bevel

Since the crown wheel teeth are inclined to the pinion, the tooth pressures are much higher. The gear oil with no
additives, and high-viscosity, suitable for the straight bevèl type, is not satisfactory when used in spiral bevel
units.
The oil film brakes down under the high loads, causing rapid wear and scoring. For spiral bevel gears special lubricants,
known as extreme pressure lubricants, have been developed. They contain additives ike sulphur, cilorine and
phosphorus compounds, which chemically react at high temperatures with the metal surface to form a compound
of low
fractional resistance.

2.13.4.2 Hypoid Gear

This type of gears (Fig. 2.13.0) is the commomly used now a day. The pinion axis of this gear is oset to the centre line
of the crown wheel.

Although the gear can be placed above or below the centre, but in cars it is always placed below to allow for a lower
propeller shaft so that a reduction in the tunnel height is posible.

Pinion ofset can väry with the application, but an ofset of one-fifth the whecl diameter is commonly used. If the axis is
lowered, the toth pitch of the pinion increases, so that for a given raio, the pinion diameter can be larger (30 percent
for normal ofset).

This enables the use of à stronger gear specifically on commercial vehicles.

Commercial
vehice
application

Pinion axis Motor car

offset to crown hypoid application
wheel centre
Hypoid

Fig. 2.13.6:Hypoid bevel

A hypoid is considered to be halfway between a normal bevel and a worm drive. In the former case a rolling action
occurs, whereas the latter case is totally sliding.

An increase in the sliding motion in the hypoid gear reduces meshing noise, but the high temperature and pressurt or
the oil film puts a strain on the lubricant. To overcome this problem, a special extreme pressure oil is used, which
contains expendable EP agents to resist scufing and wear at high temperature. It also contains a fatty acid to improved
boundary lubrication at low temperature.

Ted Keeeled
PuDlicatias

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 Automobi ssion S
Automobile IransmissionSystetne
ngineering (MSBTE Sem-
34
2.14 Differential
one 8thai to drive
Definition Different arrangement of a gear that perimit
is defned as an may berotalingatunequal
speeds
ntial egiualtorgue,although the
three shafs
S
2.14.1 Need of Differential: MSBTERW5:S

W-15
the need of differential with neat sketch
State diferenualk
QWhy diferentialis needed ? Draw heat sketch of driving wheels, then both the whel
shaft is geared rigidly to both the
propeller
In an automobile vehicle, if the
rotated at the same speed.
when vehicle takes turn or on a
will be no any problem. But
When the vehicle is driven on straight road, there
trw b
will have to cover different distance i.e. outer wheel must
the vehicle
road, the right and left side wheel of
than the inner whecl.
and outer wheels, at one of the driving wheel will tends to slip on
theroad
When the propeller shaft drives the inner
in tum.
because of this tyre wear quickly caused
wheel skidding and wheel cannot controlled

214.2 Functions of the Differential:

MSBTE:S-16.W-13

a Expain wth neat sketch hefúnction of diferentiain rearaxe S16 W16

the power that received and sends the same throngh the two half axle shaft to the diving wheels
splits
the two wheels to turm by the
same amount when vehicle goes straight path.
Italows
I allow the diving whels to tum by diferent amount when vehicle goes on curved path and delivers same powezh
both the wheels.

The speed diference between the two wheel became possible because the two half axle shaft are not directly coupled b
the crown wheel but are drive through bevel pinion and side gears, This gear system constitute
a differential.
It transmit the torgue from the propeller shaft to the half axle shaft.

It provide permanent speed reduction and also

tun the drive round through 90'. The reduction provided is about 41
car and 10:1 in heavy vehicle. This is
done either in one or two steps. For less
reduction upto about 7:1 single reductie
is used. For higher reduction is achieved in
two step.
214.3 Construction and Working of
Diferential

MSBTE: W-14, S16,W-16,S-17 W-17.S

EXplain
erential withneat sketch:
C Draw neat labelled W-14
sketchofdifferential
and explain working.
State the (S14
needofdiferéntial: Explain with neatskelch working
hydiferentialisusëdin automobile ofdifferential (W-16,W-1
? Explain workingof differential
plainthe construction
and working of diferential
with simple
linesketch
a) Construction of diferential

The differential consists

of a crown wheel
(ring gear),
two type
of bevel gear, cage
and spider or cross
an

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 Automobile Engineering (MSBTE Sem-V)
2-35 Automobile Transmission Systems

Bevel pinion

Crown wheel Planet pinion

Sun gear

Half shat

Ate

Cage-

Fig.2.14.1:Differential
The road wheels are driven by two half axle shaft.

The side gear (planet gear) on the inner ends of each the half axle shaft.

The sun bevel gear and planet bevel gear are mesh with each other at right angle. The side gears are freely mounted on
the spider or cross arm. The cage together with the bevel pinions is secured in the differential cage is bolted to the
crown wheel of the final drive.
The diferential cage has a bearing at its centre. This bearing is mounted on the left half axle shaft. This arrangement
permits the differential cage to turn independently on the half axle shaft

The crown wheel is mesh with curved teth bevel pinion which is rotated by propeller shaft.

b) Operation.

The pinion, driven by the propeller shaft, rotates the crown wheel. Since the differential cage is attached to the crown
wheel it also rotate, when the cage rotate, the bevel pinion and the cross arm which caries them moves around the
circle with the differential cage
When the vehicle is driving on a straight level road, both the driving meet the same rolling resistanice. Hence, the load
on the planetary gear which mesh with the gear on one half axle shaft side gear will be same as those on the teth that
mesh with other ie gear. As such, the two bevel pinion do not rotate on the arms of the cross. In this case all the gear
will tends to turn as a single unit without any relati've motion between them. So the whole unit rotate as a same speed as
the crown wheel.

Differential Action

.When the vehicle takes a turm on curve surface. The inner wheel meets a higher resistance than the outer wheel and
resistance at the inner wheel (which is nearer to the center of curvature) is more
hence its rotation is slowed down. The
same amont of work in a shorter distance which they travels
because of these wheels are required to do the
turnm on their spindles. This turn causes
Now the tooth load became unequal. Because of this the bevel pinions tends to
turning of the
the bevel pinion roll around the planet gear on the one of the two half axle shaft. Due to this action more
restored.
outer side gear than inner side gear thereby accelerates the same until equilibrium is
travel more distance as
Thus outer side gear shaft tum more rapidly than the inner wheel shaft. So outer wheel has to
compared to inner wheel during the same interval of time
forward at N rpm as the outer
Due to differential action, the left wheel rotates back at n pm and right wheel will rotate
wheel will be (N + n) rpm and left
wheel has to cover more distance than inner wheel. Thus resultant speed of right
wheel will otate at (N-n).

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 Automobile Iransmission Systeme
Automobile Engineering (MSBTE Sem-) 2-36
=
2.15 Axle

2.15.1 Introduction:
Slgnificance of axle
whecled vehicles, the e aaxle may be fixe
An axle is a central shaft which is used to move
rotary motion to wheels. For
rotating around the axle. In some case,
t
vehicle, with the wheels
to the
the wheels or rotating with them, or fixed supported. In the latter
tter casc, a bearing
where the axle is
mounting points
earings or bushes are provided at the the axle.
the wheel or gear to rotate around
the whecl to allow
Dushing sits inside a central hole in absorbed the shoc
well as to facilitates
the steering and ks due
the automobile as
cames the weight of the front parts of
t
to road surface imegularities.
number of road shocks.
construction as it subjected to
made very robust in the vehicle .It depends.
tis major components of cndson
conditions depend upon the weights of the
Bending load: The bending axle reaction loads are obtained
inedby
distribution along the vehicle. The
determining the load
condition by
is the static positions of the
components.
moments from the weights and
resolving forces and taking
surfaces.
travels on uneven road
considered when the vehicle
Dymamic Loading must be
The reacted at the other axle.
torsion load can be considered at one axle and
The pure tractors and in modem ight
axles. Except four wheel l,
of the four wheeler road vehicles
were provided with front
Most
independent suspension system.
vehicle are provided with
axle known as live front axle
and dead front axle.
general there are two main type of front
In
Types of Front Axle

E 2.
1. Live front axle

Dead Front Axle

Fig. C2.5:Types of Front Axle

1. Lve front axle:

is transmitted to front wheel.

Itis the front axle containing the differential mechanism through which the engine power

mechanism
For turning the front whel, a constant velocity (C.V.) joints are provided in the half axle shaft of a steering

.The constant veloeity (C.V. joints

around the king pin.

prevent the power
los through the half axle shaft and helps in turning the stb e
2 Dead Front Axle:

The dead front axle is rigid axle called as dead axle. The dead
front axle transmits the weight of front part of tne u
to the road surface through the front wheels. It also roud
carries the steering mechanism and absorbs shock aue
variation.

Tedlant
iati

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 Transmission Systems
Au tomobile Engineering (MSBTE Sem-V) Automobile
2-37

Functions and Requirements of Front

2152 axle:
Ttis made very robust in construction as it subjected number
to of road shocks.
withstand the weight of the front and rear parts steering and
absorbed uie
t must of the automobile. It facilitates the
shocks due to road surface imegularities.
other
Jt serves to transmt torgue to wheel and maintain position of wheel stéady under heavy load relative
body.
o a
and to vehicle

4 It also positions the angic ot whel hub, as in independent suspension to the left or right so as to provu
ride.

215.3 Component of the Front Axle:

1) Axle Beam:
the front axle.
Itis the major component of
.
.
They are straight axle, double
drop axle and fully drop axle. These are made by drop forging from steel having u 4
carbon or 1.3% nickel steel.
axle is made of I section at the centre portion. While the ends are made either cireular ar elliptical. 1he
The front
torque due to braking of the wheels.
section construction takes bending loads due to the load of the vehicle and also the

a)Straight axle

(b) Double drop axle

drop axle
)Full
Fig. 2.15.1:Front axle
types

is given a downward sweep.

portionof the front axle
o keep the chassis height low the centre cornering and give greater stability
as well as safety at high speed.
vehicle while
lt reduces the swing or sway of the entire centre portion.
vehicle was lowered by dropping the
gravity of the road springs fixed to the two
Ibe centre of leaf springs. The two longitudinal leaf
connection with
ne igid type front axle was used in
wheels are
spring seat on the axle beam. spindle bolt. The front
spindle by mean of king pin or
connected to wheel
Ne main front axle beam is shown in Fig. 2.15.1.
different four types of stub axle
LOUnted on the stud axles. The

Kaeuledgi
Teci
atins

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 Automobile Iransmission
ystems
Automobile Engineering (MSBTE Sem-V) 2
2.16 Stub Axle
beam.
The Stub axles are pivoted on the cnds of the axle It gets as an
axis for the wheel.
the brake drum.
Itu
which the road whcel is mounte through
to it. In conventional
nal arra kes
It is the spindlc over
knuckle arm is connccted connee
around. Stecring suspension, it is
load of the wheel and cnables it to spin pin and in independent to the
beam through king
the stub axle is connccted to the axle
suspension through the support. througn a yoke and king pin.
steering knuckle support is yoke
with the axle beam or
Lne connection of stub axle
axle beam. lubricated with grease nipple.
may be on the stub axle or on the the stub axle fork
hole in
used to bush the hole and the upper facee of
phosphor bronze bushes are face of each axle t
e
he between the lower machined
on the lower fork arms of the sk
ub axles.
provided is to be taken
Thrust bearing should be
axle fork hole
because the weight of the front portion of the car
roller-thrust bearing is employed. Thiea helpsthe
with a minimum
of effort, a
2.16.1, for steering
As shown in the Fig. king-pin.
rotated in relation to the fixed
stub axles to be
fitted in case of
heavier vehicles.
bearings are
Taper roller
axle fork.
upper arm of the stub
Fitted to the
2.16.1 Type of Stub Axle

Write short note on ype of stubaxle

alloy steel containing chromitmand
stub axle are made of 3% nickel steel and
most common inside the fork.
Reverse Elliot type is and the axle proper fit
steering head, the steering knuckle is forked
molybdenum. In this type of
inserted between the
forked end of the axle.
steering knuckle is
In Elliot type, the pivot. It is nd:
attached with the axle end by a Isedin
steering head, the L shape steering knuckle is
the Lamoine type of
.In
tractors.
most popular.
The reverse elliot type is
Types of Stub Axles

1. King pin (swivel pin)

2. Track rod

3. Drag link (Pull and push rod)

Fig. C2.6 Types of Stub Axles

Merits

(1) Itis easier to manufacture.

(2) Load exerted by the stub axle is equally distributed.

0) Iis more adaptable for use with front brake and also allows a simpler steering arrangement

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 (MSBTESe
em-Vi 2-39 Automobile Transmission Systems
Engineening
Automobile,
nobile King pin Stub axle
Thrust
washer.
-Cotter
Cotter

Stub
axle Frort
(6)
axle
Thrust
King pin
Stub washer
axle

Stub
axle Front arle
King pin

Front
axle

Fig. 2.16.1:Type of stub axles

King pin
(swivel pin)
1.

to the axle beam by pins which are made of case hardened steel.
secures the stub axle
.It
located and locked by cotter pins in proper position.
They aré
Track rod
2
. Two stub axle arms of the
front axle are connected to each other by means of track rod through ball or knuckle joint.
can be adjusted by sCrew and nut joint; hence both ends of the track od áre threaded. The ends
This length of track rod
right hand threads.
of the track rod have left hand and
turning the rod in required direction. As length of track rod
slackening the locking devices at either end as well as by
By
increase toe-in increases and toe-in
decreases as it is shorten.

3. Drag link (Pull and push rod)

section.
front axle and drop arm of the steering assembly. Itis made solid tubular in
It connects the steering am of the
arm of the stub axle
each end are provided with spring loaded ball sockets. Ir's one end is fastened to the stering
The
while the other end is fitted to the steering drop arm.

Functons:
kingpin for steering the vehicle,
1. These are help or capable of angular movement about

2 Itis able to transverse rough road without disturbing its load.

3 tallow the wheel assembly moves independentdly.
, timprove comering as well as braking characteristics
especially on slippery road.

2.17 Rear Axle

the same time.
also driving the rear wheels at
80% of the vehicle weight and
L AIC assembly supports 50% to a differenial gear
wheels through
into the two half axle shaft that drives the
1ear axle assembly can be divided
uSually through a spline connection. 7 Tech Taeuledge
PUDCOa

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 Automobile Transmission
Automobile Engineering (MSBTE Sem-VI) 2-40 Systeme
protect them from dust, damage and wat
A housing completely encloses the short axle shaft and gearsthercby
vehicle from road viDrOn.
he rear axle housing is mounted on the leaf spring to prevent the

2.17.1 Rear Axle Shaft Supporting:

The live rear axle half shaft has to withstand the following loads.

() Shearing force due to weight of body.

(2) Side thrust caused by side forces during turning.
road wheel.
the spring seat and
6) Bending moment due to offset between
the tyres on the ground.
moment caused due to side forces and reaction by
9 Bending
wheel.
6) Driving torque transmitted to road
housing.
mounting of beaing in the axle
The rear axle are clasificd às pér the
MSBTE:S17

Working of any,
diferent types of real axle. Explain
ate
1. Semi -floating type

2 Ful loating Axcl

3. Three quarter floating axel

1. Semi-floating Type
MSBTEW5S17.S19
aExplain with neat sketch, full floating ype rear axle drive W15,819
Q State diferent types otreal axle. Explain working of ahy

In this type bearings are installed in between the axle housing and the axle shaft

Wheel is fitted directly to the flanged of wheel hub at outer end of shaft by bolts, while inner end
of the axle shat
splines to the diferential side gear.

It has to support the entire load as listed above (in section 2.17.1) like side thrust
and driving torque hence the diametr
of the shaft is larger for same torque output as compare to other type axle
of supporting.
The vehicle load is transmitted to the axle through the
casing and bearing which causes bending
and shearing of the
axle.

Itis simplest and cheapest than other type of axle

and widely used in cars.
Axde casing-

Wheel hub

Axde Shait

TIITI
Taperhub
Fig.2.17.1:Semi floating
axle

TedKan
Pe ti

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 (MSBTA
TE Sem-VI)
Engineening 2-41
Automobne tomobile Transmiss
ion Systems
TloatingAxle
Ful
2
Re Axle
Rear
Working of MSBTE
skeich used in Truck W-16,S-18
Descibe with neal
ful-loating axle and explainits
neat sketch
of eature. W-10
axle two taper roller bearings are used.
ne of
placed tuwcen the axlc housing
and he wheel
Bearingsare hub. Since the
load of the vehicle
housing. is supported completely
by the axle

Bearing

Axlecasing

Flange
Axle shaft

L
Wheel hub-
Bearing
lock nuts
Fig.2.17.2:Fullfloating
axle
The axle only transmits driving torqug. The
inner end of the axle is supported
have a flange to which wheel hub is bolted.
in side gear of differential
and outer end

.During repair the axle may be removed or replace from the housing
without disturbing the wheel
by removing the nut.
This type of axle is more expensive
and heavier than other axle. This type
is used in trucks or heavy commercial
vehicles.

2:17.2 Difference between Live Rear Axle

and Dead Rear Axle:

Hvea ae Ded
1 It is a rotary axle transtnit power or motion
to wheel..
It is a rigid axle transmit the weight of vehicle
part to road siurface.
2. II takes Bending movement,
torque reaction and diving | It takes only weight of body.
thrust. Reaction and weight
of body.
3. It is not directly fixed to suspension system but through
axle | It irectly fixed. to suspension system
housing.
depending upon type of drive.

L4. Forpowertransmission
it split into two half axle shaft. Itis a complete a straight axle.

echaeuledgi
atins
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 Automobile Transmission
Automobile Engineering (MSBTE Sem-VI) 2-42 s
Systeme

Revlew Questlons

Q.1 Why transmission system is necossary for an automobile 7

Q.2 Give tho classification of clutch.

Q.3 What aro the requirements of clutch?

Q4 Explain working principlo of clutch.

plato clutch. Stato is applicatons.
Q.5 Explain with sketch working of single
spring clutch.
Q.6 Compare coil spring and diaphragm

Q.7 Give classification of gearbox.

necessity of gear box.
Q.8 Stato the function and
constant mesh gear box
Q.9 Draw power low diagram of
dectutching
gear box with double
Q.10 Explain constant mesh gear box.
mesh and synchromesh
difference between constant
Q.11 State similarity and
gear box with sketch.
Q.12 Explain epicyclile
working of ovedrive.
Q.13 Explain with sketch
working of synchromesh
gearbox
sketch,
Q.14 Explain with neat
with sketch.
axle. Explain any one
Q.15 Enlist the type of stub
component of front axle.
Q.16 Explain the
Coupling Torque Converter.
Q.17 Diferentiate Fluid
axle and dead rear axle.
Q.18 Differentiate live rear
type of rear axle with sketch.
by rear axle. Explain any one
Q.19 Enlist the load taken
slip joint used in propeller shaft
0.20 Justify the necessity of universal and

type and enclosed type propeller shaft.

021 Compare open
Q.22 Explain with sketch working
of diferential on winding road.

Shaft.
Q.23 Describe the Whirling of Propeller

024 Draw neat sketch of differential.

Q.25. Describe the Significance of axle.

Q26 State the Requirements of axle.

Q27 Draw neat sketch of full-loating axle and explain its feature.
00

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 Automobille Engineering (MSBTE Sem-VI) Table of Contents

3.3.1 Disc Brake Systerm *** *****u*******~*********

3.4 Hydraulic Brake... *ar -******************************* .3-9

3.4.1 Component of Hydraulic Brake System .3-10

UNAT ITI
3.42 Signiticance and generat procedure of
Bleeding of Hydraulic Brake 122
3-1 to 3-335
***

Chapter 3: Automobile Control Systems

******* *******************

3.5 Pawer Brake . 3-13

Sylabus:
3.6 Pneumatic or Air Braking System. .3-14
3.1 Automobile Braking System: Function and Requirernent af
Braking System Principle of Braking. Basic Terms reiatecd to 3.6.1 Advantages and disadvantages ot
Braking (Slopping Distance, Braking Efficensy, Fadingof airb akes over mechanical brakes .3-15
Brakes)
3.7 Aritilock Brake Systern (ABS).- -3-16

3.2 Types of Braing System: Layout, Construction, Wotking of 37.1 Warking ot Antilock brare system . 3-17

3.3
Drum, Disc, Hydraulic and Air Brakes.

Master Cylinder, Wheel Cytinder, Tandem Master Cylinder,

3.7.2 Pressure Modulatdon Valve .
************************** .3-17

Significance and general procedure of Bieeding of Brake 3.7.3 Ant-Lock Brake Types .3-18

3.8 Diference behween Mechanical

3.4 Review of Anti Lock braking System: Layout of ABS,
and Pneumatic brake systam- 3-18
Pressure Modulation, Types of ABS.
3.8.1 Diference between Hydrautic
3.5 Automobite Steering System: Function and Requiremerts
and Pneunatic Braking System .3-19
of Steering System: Basic Terms related to Steering
(Steeing Ratio, Turning Radius. Understeering and 3.9 Compaisn of Disc and Drum Braka.. -19
Oversteening) Basic Components of Steeing Linkages.
3.13 Steening System.. 3-20
3.6 Types of Steering Geer Boxes: Construction and Working
3.10.1 Purpose (Requirement) of Steering System
of Rack and Pinion, Recircutating Bal!l Type Steering Gear
3-20
Box, Neoessity and Principle of Power Sieerng. 3.10.2 Function of Steering System- 321
Constructhion and working of Hydraulic and Electronic Power
3.11 Basic temm related m Steering 3-21
Steenng
311.1 Steerng Ratio (Reduction Retio) -321
3.7 Steering Geometry: Necassity of Steering Geometry,
Significance and ranges af Caster (Pasitive, Negative), 3.112 Tuming radrus 321

Camber (Positive, Negative), Toe-in, Toe out, King Pin

311.3 Understeering and Overstaerng -321
ncination (KPI), Steering Axis inctinaton (SAI.
3.11.4 Basic Components of Steering Linkaga.. 3-23
3.1
introduction to Brake. *********************************************

3 12 Types of Steering Gear Boxss

31.1 Requirements of Brake.**************** **"
3.121 Rack and Pinion Steering Gear-
3.1.2
Basic term related to Braking.
3122 Recirculating Ball Type Steering Gear 3-25
3.1.3 Principle of Braking 4
3123 Necessity and Principle of Aower Stcecn 327
3.1.4 Braking efficiency
***************************************************
3124 Eleconic Power Steeing
3.2 Classification of Brakes. -*** ********a* *

************* 3-5
3.13 Steering Geometry
3.3 Mechanical Brake.
e a a** **
********
*~**

etrtcaaraat
 Automobile Control
Systems
Unit-1
Sylabus:

a Antomobile Braking System: Function and Requirement of

Braking System: Principle of Braking, Basic
Tems
related to Braking (Stopping Distance, Braking Efficlency, Fading of Brakes)

Braking System: Layou, Construction, Working of Drum,

32 Types of Disc, Hydraulic and Air Brakes.

33 Master Cyinder, Wheel Cylinder, Tandem Master Cylinder, Significance and general procedure of Bleeding of
Brake.

34 Review of Anti Lock braking System: Layout of ABS, Pressure Modulation, Types of ABS.

35 Automobile Steering System: Function and Requirements of Steering System: Basic Tems related to $teering
(Steering Ratio, Tuming Radius, Understeering and Oversteering), Basic Components of Steering Linkages.

36 Types of Stering Gear Boxes: Construction and Woiking of Rack and Pirion, Reciraulaing BallType Slering
Gear Box, Necestity and Principle of Power Stering, Construction and working of Hydtraulic and Electronic
Power Steering.

3.7 Steering Geometry : Necessity of Steering Geometry, Significance and ranges of Caster (Positive, Negative),

Camber (Positive, Negative), Toe-in, Toe out, King Pin Inlination (KPI}, Stering Axis Inclination (SA)

BRAKE

3.1 Introduction to Brake

stopping the vehicle within smallest
Brake is one of the most important device of a vehicle used for retarding or
The brakes also used to hold the vehicle at rest
possible distance, in consistent with safety and without wheel skidding.

on an inclined road against the pull of gravity.

both while remaining in action and this absorbed
energy
The brake absorbs either kinetic energy or potential energy or
engine is
de-accelerating a vehicle at a faster rate than the
appears in the form of heat. The brake must be capable of
engine power in its equivalent form.
able to accclerate it. Normally brakes absorb three times of

Functions of brake:
ASBTE:W-16

parking brakes
V-16)
D Cessity of braking system Whatis function.of

tis used as emergency of brake to avoid accident.

holds vehicle stationary on slope or steep road for parking
9) tcontrol the vehicle to be retained when descending a hill. wncc
in consistent
with safety and winour
possible distance,
ugskidding or stopping the vehicle within smallest

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 Automobile Controls
Systethe
Automobilo Engineeri (MSBTE Sem-VI) 3-2

3.1.1 Requirements of Brake: emergency but thi.

an should
short distance in
the. vehicle within a ver has proper cont d
(1) The brakes
must hbe strong cnough
must to stop
only when there is no whecl
skidding and d l over
te
consistent withsafety. This is possible
vchiclc during emergency. effectiveness the brake should be remain
ofthe
characteristics i.e. the
(2) The brake must have
h good antifade
prolong application.
driver.
minimum effort of the
brake must operate with the
9The braking force.
sustain sudden large
9The brake must be strong enough to
any wheel skidding
)The brake should not cause

3.1.2 Basic term related to Braking:

Basic term of brake

Brake torque
1.
2. Brake fade
3.Stopping (Braking) distance and time

4. Brake safety
Coefficient of friction
5.
6. Brake balance

a7 Road

Fig.c3.1: Basic term related to brake

1. Brake torque

The braking torque is the twisting or torsional action

caused by the disc or drum on
the brake shoes or calliper anchor
during brake application.

The torque is depending upon effective

axle height and braking force
between road surface and
tyre.
Braking torque is higher in emergency
stop than acclerating torque, hence anchor
have sufficient strength pin supporting brakeshosmut
to withstand this high braking load.
2 Brake anti-fade characteristic

The brake linings are

poor conductor of heat
so most of the heat dissipated
disc. during braking is absorb by brakeanun

The coefficient of friction

between drum/disc
and brake lining
pressure is required. is much lower at this temperahure additiona
henoe
After prolong period
of aplication of brake
which causes less the coefficient
braking effect. of friction drop and changes
This called brake the property of brakematc
fade.

Yhlti
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 Automobile Engineening (MSBTE_Sem-VI)
3-3
ooling spacc is
In drum brake, cool less duc to large
Automobile Control
Systems
internal surface
more susceptible to fade than disc brake. is covered by brake
lining. Therefore
drum brake are
move air cooling is directed
As vehic around the drum
and disc to
remove brake
drum brake,
hrakc, cooling space is less heat.
In due to large internal
surface is covered
more susceptible to fade than disc brake. by brake lining. Therefore
drum brake are

ls vehicle move
air cooling isdirected around
the drum and disc to remove
brake heat.
gencration in braking,
heat
ue temperalure increases
which causes
expansion of drum
ncease so brake shoe are no longer to match the drum so effectiveness
drum i and disc. The diameterof
ofbrake decrease.
3.
Stopping (Braking) distance and time

important in cmergency braking. It is

I is verv based on etardation
rate. Also it affected
by the tyre deflection, air
resistance, inertia force of drive and engine braking effort.
T
distance required to stop the vehicle is proportional to the square
of the speed at which the brakes
are applied
Ttis inversely proportion to brakes eiiciency and is measured in feet or in meters from
the point of application of
brakes and to the point where the vehicle come across to stop.

.Many types of decelerometers are in use to check the Stopping distance and thus to find brake efficiency.

Stopping distance metres

Where, Vis initial velocity in m/sec

m/sec?
And ais deceleration in

Stopping Time is the duration of brake application to the vehicle come across to stop or at rest poition. It is inversely
proportion to brakes efficiency and is proportional to the speed

Stopping Time = (V/a)

4. Brake safcty

and it operates independently with service brake.

automobiles are equipped with emergency brake
All
the operator.
The emergency brake is hold the vehicle on a 30%
slope indefinitely after brake has applied until

5. Coefficient of friction
heat.
consuming power of cngine and produce
Fictional force opposes the motion of vehicle
brake applied.
The friction occurs between rolling/sliding tyre and road surface when
surfaces.
friction between rubbing
vehicle is related to coefficient of
0e inetic energy of vehicle and to stop the
6. Brake balance
wheel skidding ocus
applied and
condition, when brake
distance is same with the same tyre and road below uns
Pping So non-skid brake system are
design to operate at or
U of weight, number of wheels and load.
point c.u.
kinetic energy acts througn
level. The vehicle weight and
braking force of a vehicle occurs at ground
VE
bove the ground
level which causes vehicle tend to pitch
forward as brake
applied.
Tedh Laedg
P tigss

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 Automobile Control Systems
3-4
Automobile Engineering (MSBTE Sem-V) more K.E. The mari
wheel absorb aximum
front wheel so front
from rear to
pitching action transfer vehicle weight
The
weight transfer ( W)

W
Wherc y wheel base,
ground
h distance of C.G. from

coefficient of friction

vehicle.
W Total weight of
wheel.
static load on the font
wcight should be added to
This
Road surface and it is varies with thetype
thn of
7. depends upon the road
braking resistance is
resistance as well as
The tyre roling travelling.
which the vehicle is
road surface over sand and clay,
concrete.
Asphalt, flat unpaved surface, Gravel and
The road are of and the road surface.
by generating friction between tyre
stop
Automobile decelerate and condition, tyre type and
tyre construction.
generated depend upon road surface
force
The amount of braking is braking distance.
fictional coefficient. Small is value larger
performance is evaluated by its
The braking perfomance is poor. On concrete
it is larger and brake
braking distance is small while on wet road
On dry road surface
but tyre wear is more.
the brake efficiency is more

3.1.3 Principle of Braling:

vehicle. During accelerating the
action of that applied during acceleratinga
The principle of braking is the reverse
momentum or kineie
chemical energy of fucl is converted into
kinetic energy of a vehicle. In braking the power of
surface of
energy by means due to friction betwcen two moving
energy of the moving vehicle converted into heat
brake drum. The tractive effort produced at the peripherics of
the driving wheel by torque of engine during diving

vehicle the brake torque introduced at the brake drum due to application of brake
produces a retarding cffort bythe
and the
adhesion available between brake lining and brakc dnum and between adhesion available between wheels
ground.

The heat generated at the contact surface of brake drum and brake shoe depend upon the pressure or force on the shocs
and coefficient of friction of two materials, so the fading characteristics must be good or heat of brake should be eany
dissipate to atmosphere to prevent the effectiveness of brake.

.Retarding force of friction on the brake drum,

Wherc,
a Coefficient of friction between lining and drum,

Wa Normal force on the brake shoes.

Retarding torque =
FxRa
Rg Radius of drum.
Retarding force at the
point of contact of the tyre
on the ground,

T ltatin

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 Systems
TAutomobile Engineering Control
(MSBTE
Automobile
Sem-V)
3-5

Wherc RT = Radius RT
of tyre,
Retarding forc on
road wheel(friction
between
road and tyre)

Where,
H Cocfficicnt offrictionbetween
WT tyre and road.
Normal force
on the tyre
3.1.4 Braking efficiency:

.Itis the ratio of retarding

force to the weight the
wheels to stop vehicle of vehicle. resistance applied at
or reduce the It mum retarding force of
is the maxim and
the componcnt of weight speed. It depends tyre surface
of vehicle on coeficient of friction between the road and
pends on coefic
the whecl.
If unity cofficient of firiction
is achieved,thetotal
then the 981m? e total retarding force produce at the wnewheel is equal to weight of vehicie
GT retardation is
brake is 100%. Ing eticiency is considered as 100% Thus therotical efficiency limit 1or
The checking of brake
without the
particular speed aid of proper testing equipment
from the moment stopping(5rakng
of application of the
brake is measured.
The instant when the brakes
exactly
difficult. Ciect take effect with maintaining vaiue atuthis moment is quite
maintaining the speed at exact value

Some other ditfficulties like variation

in gradient, iregularities applying brakes
stopping distance are libel in as well as wheel skidding aung
to arise.
The testing of brake is done either
by static brake testing machine or
by a decelerometer.
Wheels of the motor vehicle are
rest on the rollers of a static brake testing machine.
will be tuming. By rotating the roller the wneel

Now the brakes are appied and the resistance

to rotation at cach wheel is indicated. This method used only
speed without considering the road conditions. for low

A decelerometer is quite an accurate instrument which gives direct' reading of brake efficiency without
any
consideration of speeds.

This instrument is attached to a heavy block and placed on the floor of the car or mounted on a vehicle. A calibrated
scale visible through the window in the instrument will indicate the percentage brake efficiency.

Stoping distance required to bring the vehicle to dead stop' condition varies direculy to brake efficiency. When the
m/sec
brake force equal to weight of the vehicle or the rate of deceleration is 9.8
wheèl skiding when 80% efficiency on dry road is used on
.The efficiency is said to be 100 %. But the risk of front
slippery roads.
affected by condition of the brake. The stopping distance is also depends on the speed of
The brake efficiency is also
efficiency of the brake.
the driver's reaction as well as

Classification of Brakes
3.2
MSBTE: W-17

W-17)
classilicationotbrakes.and.braking systems

classificd as follows:
The brakes are

eelegi

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Automobile Engineering (MSBTE Sem-VI) 3-6 Automobile
ControlSr
Seta
Classificatlon of brakes

1. According to purpose
renetheeoenez

(a) Primary or service brake

(6) Secondary or parking brake

2. Accordingto location
H (a) At the transmission

(6) At the wheel

HO Two wheel brake

i)Four wheel brake

3. According to construction

H (a) Drum brake

Disc brake
6)
4. According to method of actuation
H(a) Mechanical brake

H (6) Hydraulic brake

H () Electrical brake

H ) Vacuum brake

(e) Air or pneunatic brake

5.Accordingto extra-braking effort

H (a) Servo-brake or power assisted brakes

b) Power brakes or power operated brake

6. According to application

H (a) Foot brake

(6) Hand brake

Fig.C3.2: Classification of Brakes

Te

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 Automobile Engineering (MSBTE _Sem-VI)
3-7 Autormobile Control Systems

3.3
Mechanical Brake

Mechanical Brake

. Hand brake or Parking brake

2. Drum brake

3. Disc Brake System

4. Girlingbrake
Fig. C3.3:Types of
Mechanical Brake
Drum brake
Mechanical brakes are
obsolete now as a service brake and
these are still used on rear wheel
emergency brake. in cars as a parking or
The details of the drum type manually
operated mechanical
wheel is attached to the drum. brake system shown in Fig. 3.3.1.
In a motor vehicle, tne
.The drum encloses the complete
brake mechanism and
protect it from dust and moisture.
open. The backing plate at the open The inner side of drum is
side of the brake drum
completes the brake enclosure and
The backing plate is attached to hold the brake assembly.
the vehicle axle housing and
acts as a base or frame for fastening
operating cam mechanism with the brake shoe and the
it linkage. The wheel attaching bolts
on the brake drum commects the wheel and
From Fig. 3.3.1 The two semi drum.
circular brake shoc having brake friction
or lining on their outer surface.
The brake shoe are hinged to back
plate at one end by an anchor join while other
can be tun by camshaft which passes through end rest on cam or toggle. This cam
hole in backing plate.
The camshaft can be operated by brake
pedal through linkage. The brake shoe are pull
inward or held by retracting
spring.
When brake pedal is pressed, the cam tum by expanding brake
shoe outward, against the retractor spring
force.
The brake lining comes in contact with brake drum
causes friction between them. This force of friction
opposes the
direction of rotation and educe the speed or stop the. vehicle
when brake pedal release, the retracting spring
brake shoe inward which turn the cam and brakes are release. This
pull the
type of brake are called Internal expanding
brake

Brake pedal

Cam operating lever

Cam-

Pivot Backing
plate
Brake drum-
Brake shoe

Flg. 3.3.1: Mechanical Drum Brake

Tedieed
PDilCatl*s

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 Automobile Control Systen
3-8
Automobile Engineering (MSBTE Sem-VI)

3.3.1 Disc Brake System: metal disc instead of

dnum.
nand
disc
orcaliper brake has a
automobile are cquipped with disc brake. The
a day the the drum brake.
Now flat shoe instead of the curved shoc used with ne pad and metal haa
mietuOn
a pair of pad or the piston, ack
brake are the disc, the caliper having wheel hub. The metal disc revolk
The essential
components of a disc mounted on the
are attached. The rigid
metal disc is brakc
plate. To which friction pads a rear wheel
brake and to the axle housing in aces inside the calipe
machined surface
betwecen the jaws of the front
wheel position by
held in
disc and are
each side of the
The friction load ride freely on
casting and the spring behind the hydraulic
pistons. two shoes are located on each
fixed caliper type, the
caliper. In
fixedcaliper and floating pressure is sent from
setfrom the master cylinder
art general two types, The fluid under
Ne
side of the disc when the driver,
lepresses the brake
pedal.
as shown in Fig.
3.3.2.
unit behind the piston
uhrough the connecting tube into
the caliper pressure on the disc as like squeeze
sm
pressure. The shoe exert a
against the disc by the
hydraulic eue*
friction between the pads and the revolving
ne shoes are now force you picked it up. The
first finger as
prcce of paper between your thumb and
speed is reduced.
action thus vwheel
disc then provide the braking Caliper

Supply of
under-
fiuid
pressure

LPiston
LFricion pad

Fig. 3.3.2: Braking Action of the Disc Brake System

The disc brake may be of a single piston caliper or a double piston caliper type. The master ceylinder locatod in te
handle bar of two wheeler.

In single piston floating caliper as the hydraulic pressure is applied,

the piston move the pad toward the disc. When the
load makes the contact with the disc, the caliper body floats
on the caliper shaft. This bring the caliper pad (fixed pad)
on the opposite side also to come in contact with the other side if the disc.
As further pressure is applied, the disc s
pinched between both pads.

In double piston caliper, hydraulic

pressure is applied equally on two
both pad moves forward
piston on each side of the caliper. This cu
and makes contact with the disc. Hence
the disc is pressed between the pads.
Disc braké is notselfenergizing
as the drum brake. As such brake
requirement Their chief more force is needed to apply them
advantage is their resistance for De
application. to fading, since disc remain cool even under repa d
brake

Advantages of disc
brake
(1) Better coling
(2) Lighter in weight
(3) Better antifade
characteristic
4) More efficiency
(5) Quickbraking
action

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 Automobite Enginoering(MSBTE Sem-VI)

Hydraulic Brake 3-9 Automobile Control Systems

3.4

Explain raulic braking system

with neat
MSBTEWA5:S37
Whatarethe components.of sketch
hydrautlic braking W-15)
s
As compare to chanicalbrakes,
efficicnt, durable and
these brakes S17
simple in design. system
is silent, flexi
hydraulic lubricating. Also this system is highly
he braking system
based on pascal
without any loss. law which
states that the
fluid transmit pressu irection
This system is desi in such
nipeline to protect
a way that even
the entering brakes
NS are
of air in the aTt in released
system when po
position, a small pressure must
be maintann In
This system consist of master
cylinder,
cup of wheel cylinder
wheel cylinder, are kept expandea.
end of master cylinder.
steel pipe, flexiblet
When operator
se, brake linkage and a check valve att
pressed the brake
pedal, this force
is transmitted
.The piston in master cylinder
moves (to
to the piston in master cylinder
through linkag
covered, a further leftfrom Fig,
movement 34.1) by compressing
of piston build ng the reun spring. As bypass
up, the fluid check valve up pressure port is
deflect and in the compression chamber,
fluid under when sufficient
pressure in presSure 13 built
Du
As soon as the fluid enter the pipe line enters
in wheel cylinder, in wheel cylinder.
motion of piston exert a pressure
causes the brake on two piston to move
shoe expand the piston outward. This
creating tension outwar
The brake shoe lining press inretracting spring.
tightly against intemal
slow down or stop surface of brake
the rotation of drum drum. This fiction
between brake lining
hence vehicle slow and drum,
down or stopped.
As brake pedal rcleased,
the retracting spring
wheel cylinder pushes pul the brake shoe inward onginal
back. Due to this the position, this canses
brake fluid flow reverse the piston in
reservoir. in direction i.e. to the
master cylinder and
to fluid
As the pressure drop
in the fluid line the fluid check
valve at the end of
master cylinder closes.
Advantages of Hydraulic Brake

(1) An equal pressure is applied

at all point in the system, thus
equal effort can be applied
compensating. to each wbeel. This system
is self
(2) Even ifall the brake shoes are
not adjusted equally neár the drum, braking
effoit will be samie on all
(3) A differential braking action can the wheels.
be achieved by using different size of wheel cylinder
for front and rar.
(4) Less friction losses.

5) Asit is self lubrication, less wear and tear.

(6) Application of brake is very smooth.

(7) Minimum moving parts and less complicated linkage.

Disadvantages of Hydraulic Brake

(1) Any breakage or fault in the system causes pressure loss, affect the complete hydraulic system.
(2) If the brake fluid leak out on the brake shoe, they will be muined (destroyed).

3) Slightly leakage of air in braking system, imake it useles.

caulelgi
atless

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 Automobile Automobile
Engineering(MSBTE Sem-VI) 3-10 Control
Sysete
Brake shoas
Brake drum
Retracting
spring
ww Master wws Rear o
JMnder the vehicle
Front of Brakd
the vehicle pedal
Wheel
Pi5ton(G-Pivot cylinder
Pistons
Retum Fluid line
spring

Brake shoe

of Hydraulic Braking System

Fig. 3.41: Layout

3.4.1 Component of Hydraulic Brake System:

Component of Hydraulic
brake system

cylinder/Tanderm
(A) Master cylinder
master

e Wheel cylinder

(C)Fluid check valve

Fig. C3.4:Component of hydraulic brake system

(A) Master Cylinder

s16.S-17.S

QOravneat ebelled sketchof masteryinder cn ycraulc brake and explain working

Anconstucton and wonking of masteEEylinder

The master cylinder consist of two chamber a fluid reservoir and compression chamber.

A fluid reservoir contain oil or fluid with a Filler cap at top with small air vent to keep the brake fluid
at atmaspheic
pressure. Both the chamber are connected by two port

The smaller one is called intake port and larger one called compensating or bypass
port.
A piston operates in compression chamber.
There are number of holes in the piston head of the high
pressure side. The reduced diameter of piston is alwas
survunded by the fluid.
At the discharge end of the compression chamber fluid
check valve with a rubber cup inside. serve to retain
residual pressure in the brake line when brakes
It b
are in released condition.
A piston returm spring and to prevent
the leakage there are rubber seal
chamber.
on both ends of the piston in the compreso

When the brake pedal pressed,

the push rod moves toward
left by moving the piston against the spring forcCas
bypas port, a pressure built up in the
compression chamber va
deflected and the fluid under
pressure flows in the pipeline.
when sufficient pressure built up, the
tua cDsck

Tdn

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 (MSBTE Sem-VI)
Automobile Engineering 3-11
Automobile
ControlASystems
Air vent
Cap
IL
Fluid reservolr
=Body
Primary Stop
washer
seal
Compression- By pass
Circip
chamber Intake
Puah
rod

Fluid
check valvee
-Rubber
cup
L-piston
spring
rehum
L Secondary W seal
-Rubber
boot

Fig. 342: Master

cylinder
when the brake pedal release, the
spring pressure in the master
Fig. 3.4.2). cylinder moves the piston
toward ight (from
This same force of spring keep the
check valve pressed on
the compression chamber. its seat for sometime there
This delay causes vacuum compression by delaythe retum of fluid into
into the system. This vacuum in chámber and there may
is destroyéd by cnteting be chance of air leakage
piston which deflect rubber cup and the fluid from reservoir through
enter in compression chamber. intake port and holes in the
(5) Tandem Master Cylinder

In this separate luid lines go

to rear and front brake and
rear brakes will be still effective it is so arranged that if thefront
similarly if rear brake lincs brake lines are damaged, the
are defective, front brakes are
During normal working the brake fluid transmit to åpplied.
both front and rear brake when
brake lines are damaged, brake pedal pressed. Consider front
the piston 'b' will moves till
space between 'a' and
it comes up against stop after this
'c' pressure start building up in
'b'.and rear brake applied. Similarly when
space between piston rear brake line damage no pressure is build up
'a' and 'b'. So piston moves freely till comes in the
moves both it up against "b'. Further movement of brake pedal
a' and 'b' togcther thereby applying the front brake.

Fluid reservior
Intake Bypass
By pass Intake
port port port
pot

Push To front
brake

Piston (a)
To rear Piston ()
brake
Fig. 3.4.3
ecamde
PCata

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 Engineering (MSBTE Sem-VI) utomobile(ControlSysterms
Automobile 3-12
Function of fluid check valve
to flow in Tiud nne and again it
It helps to developed sufficient devclopment of fluid pressurc in master cylinder on
It return the Tluid rom cOmpression chamh
up to complete fluid return in master cylinder function of by-pass port. iber

to fluid rescrvoir when brake releascd.

(C) Wheel Cylinders

Dust Inlet port. Retum
spring
cOver

Cylinder

Rubber Bleed -Seal preader

seal port

Fig. 34.4: Wheel cylinder

In the drum type brake, each wheel has a wheel cylinder. Each wheel cylinder has two piston.

Each piston is linked to a brake shoe by an actuating pin or the end of each shoe resets on a piston. Also there are nutber
cup, cup spreader, spring and dust cover.

The brake line from master cylinder is connected to the inlet port and a bleceder screw to remove the air from the systm

When the brake fluid from master cylinder cnter in the whel cylinder exert a pressure on piston to move outad
against the drum. When brakes are releascd the brake shoe retractor spring forces the brake fluid out of the wheel
cylinder by pushing the piston inward.

3.4.2 Significance and general procedure of Bleeding of Hydraulic Brake:

During repair or replacement of any part of the braking system air may trap or enter.

As in hydraulic braking system care must be taken that not even small quantity
of air enter into the bydraulic braing
As air is compressible, the braking effort is not transfer to
the brake and brake failure occur. So it is necesay
remove the air from braking system.
Back plate
rFluid line
Wheel cylinder
Master
yinder
UBrake
Bleeding
pedal
nipple
Brake fuid

Jar
Fig. 3.4.5

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 Automobile Engineering (MSBTE_Sem-VI)
3-13
Automobile Control
Procedure: Systems

rocess of removing air from the braking system

is known as bleeding
of brake.
bleeder screw is provided to the wheel cylinder looscn
Ab the bleeder
scTew.
rubb
A picce ofrubber pipe
is connected to nipple of the blecder
screw and other
containing the brake fluid. end of the pipe
is kept submerge
erged in a far
reservoir of the master
r cylinder is completely
The filled with the brake
fluid during the
eder Sscrew is then loosencd or turns. Lne orake pedal
is press and
bleeding operation.
allowed to come
uid is pump through the piping system and out through the bleeder up for several time
so that
screw into
is cOntinues until the fluid corming Out
is seen to be free of
air. Thebleeder
the jar.

der screw throughout the system is to

be treated in the same
screw is then tightened.
manmer and any
completcly let out. air in the system should
be

3.5 Power Brake

Rmke operated by power other than physical effort applied

at the brake pedal, are known
as power brake. The power
may be exerted by air pressure, engine vacuum, or electrical energy.

.The following are the types of power brakes are

Types of power brake

1.Air brake

Vacuum brake
2.
Electric brake

Fig. C3.5: Types of Power Brake

. Air brake: Apply compressed air to operate the brake mechanism.

2 Yacuum brake: It utilize engine vacuum to actuate the brake.

EMectric brake: Uses electrical energy from the battery to operate the brake mechanism
supplements the power in actuanon tne
c power or power assisted brakes in which the power assists or
brake,
hydraulicaly operalied
assist in the actuation of
iKe are semi-power brakes. There is the engine vacuum
hbrake.
The main features
of power brakes are
pressed down and ine
The time movement of the brake pedal
or the time lag between the actuation
EV
OVement of the brakes are
put on, is very smal. the brake pedal
2 applied by the driver on
Thebraking force
force applied should be closely proportional to the applicaion of brake 1ary
.The the intensity ofthe
sense or judge
such that the driver may
accurate. be
TecMneuaedge
tiuas

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 Automobile Engineering (MSBTE Sem-VI) 3-14 Automobile
ControlSystema

3.6 Pneumatic or Air Braking System

MSBTE W-14,
W-17.S-18.Wa
Descibe pneumatic braking system with neat sketch and staté adyantag

Descrbe pneumatic braking system with neat and state its advantages W14
Draw the layout of air-braking system. Explain fits woiking

State the components of pneurmatic braking system wilh

r'suncion
An pncumatic braking system is
used in medium and heavy duty vehicles. This system
has following advantages
(1) The pressure on the pre-compressed
air allow any force required for braking
to developed very smal effort
by the driver to the brake pedal. aplied
apnlo

(2) The compressed air can used

be for many purposes like to inflate
the tyre, drive windshield wiper,
gear etc. actuate steering
steer

3) This system is most convenient for full trailers

and semi-trailers.
The layout of air braking system
shown in above Fig. 3.6.1(a).
reservoir, brake valve and brake It consists of air filter, air compressor,
chamber with steel tubes unloader valve
and flexible hoses.
Pressure P
gauge
ir
Compressor
seperator
s Unloadingg
valve
Air receiver

To
accessoriess
Brake
pedal
Hose
Brake valve
Brake chamber

Frort
Hose
Tee with quick Rear
relese valve
Compressed air Tubing tee
(9To 10 Kscm)
Hose

Hose Slack
adjuster

Fig. 3.6.1(a): Alr

braking system
The compressor is operated
by engine. The compressor
it to high pressure and discharge suck the air from atmosphere pressed
to the reservoir through through air filter and coug
oil separator.
The pressure gauge
is fitted to reservoir
air for several braking operation. to indicate the pressure
in the tank. The reservoir containenou compressed
The air from reservoir
tank is supplied
There is no braking cfíect until to brake valve and to otheracessories.
the brake pedal not pressed as
chamber. is brake valve prevent passag¢ Or the brake
the

T
PiCti

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 (MSBTE_Sem-VI)
Engineenng 3-15
Automobile Automobile
Breather hole Control
ystems

Diaphragm

Sprng
Compressed-
To
all brakes
Push rod

Pressure
chamber

Fig. 3.6.1(6): Brake chamber

valve
brake pedal is
presSed, the brake valve changes its position and brake open.
when
mpressedairfrom brake
valvefl to brake chamber acts on the flexible diaphragms in brake chamber.

pushestherods connected with the levers of brake gear cam. The cam tum and expend the brake shoe
The diaphragm
with make frictional contact with brake drum thus braking the wheels.

pedal is released, the supply of compressed air is cut off from the brake chamber and they are connected to
When brake
atmosphere.
are returned to their initial position and wheel nun fre.
The pressurefrom the chamber drops and brake shoes
braking force on shoe proportional to the
The brake valve is
equipped with servo-mechanism which ensure that the
the degree
force on the pedal and also
import relative reaçtion to the movement of the pedal. So driver can sense
applied

of brake
application.
valve is relieves the
compressor and reservoir air pressure line. The unloader
unloader valve is located between the
An unloader cut out pressure is obtained and seal the
reservoir.
compressor of its pumping load once the
upon the setting of the adjusting screw.
pressure depending
When the compressor is built up a
Thus allowing the compressor to
runm
atmosphere.
The umloadér then delivers the air
discharge by the compressor to the
supply of air.
light while the reservoir contains sufficient chassis andd
These are mounted on the
material entering the operating system.
foreign
The air filter prevents the dust and easily removed.
have a druin plug to allow the condensate to be

over mechanical brakes :

4.1 Advantages and disadvantages of airbrakes
Advantages

1. Quick braking effect.

Regquires less effort by the driver for braking.

reic.
. for inflate the tyre, drive
windshield wiper, actuale
siecning Bea

aur can be used

onvenicnt for full trailers and semi-trailerS.
Dsadvantages

Small leakage
of air causes brake failure
omplicate
in construction.
Requires analelgi
Air pressor, so cost is high. latiens

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 Automobile Control Systema
16
Automobile Engineering (MSBTE Sem-V)

System (ABS)
3.7 Antilock Brake
control device that prevents wheel lock up during braking and asaa result
Anti-lock Braking system is a closed loop
vehicle stability and steering is maintained. This
system uses the principle of cadence braking and threshold brakino

ABS reduces the risk of tyres skidding under

heavy braking and allows the driver to maintain steering control of the
car.
ABS only operates under heavy braking or on slippery
surfaces.

.About 40% of allcars accidents involve skidding.

The most efficient braking takes place when the wheels are the stll revolving.

If the brakes lock the wheels so that the tyres skid, kinetic friction results and the braking is much less effective
To prevent skidding and provide maximum effective braking, several antilock devices have been developed.

Some provide skid control rear wheels only. Othes provide control at allfour wheels.

The ABS is a electronic system which uses sensors like wheel speed sensors and actuators as
ABS pump and
valve
This is achieved by EBD which is a sub system of ABS. Hence EBD also prevents wheel from
locking under vario
driving condition by regulating brake pressure

Working principle: The ABS modulates the pressure of the brake fluid
that is applicd to each front and
rear brale
preventing the wheels from "locking up" and maintaining
the steering control over the vehicle. Its purpose
is to prevent
instability of the vehicle under extreme braking conditions.

.The Antilock Braking System (Fig. 3.7.1 and 3.7.2) located

is between the brake master cylinder and the wheels The
system constantly monitors each wheel through
an electronic wheel sensor; if one of
the wheel is tuming slower than
the others, the antilock system releases the pressure
on that wheel.

EMaster

Hydraulic
control uinit
wheel speed
senor

Motor
fansmlssion Braka
contro
uni
nro unt

Motor
Converter ergy unt

Llquid
CuTent Control Mechanical

Fig.3.7.1:Antilock
Brake System
Flowdiagram

latin

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 (MSBTE Sem-VI)
tomobile Engineering
Autom 3-17
Automobile Control Systems
Power Brake Rear drum
waming
brake brakes
Pressure- unit
ight
differential
valve

brakesy

Proportioning
valve
Metering valve

Fig. 3.7.2: Layout of Antilock Brake System

3.7.1 Working of Antilock brake system:

ABS systems have an individual brake line for each of the four wheels, enabling different braking pressure on different
road surfaces.

Vehicle wheels may be lock-up due to excessive whecl torque over tyre road frictio forces available, caused by too
much bydraulic line pressure.

The ABS monitors wheel speeds and releases presure on individual wheel brake lines, rapidly pulsing individual
brakes to prevent lock-up.

.Three channel systems are equipped with a sensor for each wheel, but control the rear brakes as a single unit. ABS
detects the right wheels about to lock and reduces braking force on the whel.

The system would also reduce force on both back wheels. Both systems help avoid lock-up and loss of vehicle control.

Control means that as long as the wheels are rotating, the antlock device permits normal application of the brake

But if the brakes are applied so hard that the wheels tend to stop tuming and a skid start to develop., the device comes
into operation.

It partly releases the brake so that the wheels continue to rotate. However, braking continues, but it is held to just below
the point where a skid would stat. This result maximum braking effect.
Tyre torque
Seldom wheel
Desire speed
relative
slip ctr Rr (tyre torque)
Weight
Vehide speed
angudar

Move slip
friction curve

Vehicle-
speed Stopping
distance

Fig. 3.7.3:Antilock braking (ABS) model

3.7.2
Pressure Modulation
Valve:
TheBrake Pressure by the
Modulate Valve is controlled thepressure modulation by the electric signal that is generated
ABS module.
This valve r wheels. The modulate
the pressure that is supplied to each ABS controlled brake in the
valvehas
a set of s
Tgulates
valves, usually one for each wheel, that are controlled by the ECU. In normal braking condiuons,
enoid
edanledgi
Pallcatius

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 Automobile Enginoering (MSBTE Sem-VI) 3-18 Automo
Control

the brake master cylinder provides a

constant pressure to all four wheels of the vehicle. When the ABs s. Sens
emsenses
wheel is about to lock up, it scnds the appropriate signal to the Pressure Modulator. In response,
thata
the valve coresponding
co.
the faulty whcel is opened or closed to cither supply more pressure to the affected whecl or to cut off the
Kessure
pre
the wheel. Once all the four wheels are back to spinning at the normal speeds, supply
the ABS switches off and all
brake pressure modulate system are madc open again to supply an cqual
h valves o
Advantages of Antilock Brake System
amount of braking pressure to
all 4 h eels. e
e
1. ABS reduces the risk of tyres skidding under heavy
baking.
2. Allows the driver to maintain steering control of
the car.
3. Increased braking comfort

4. ABS only opcrates under heavy braking

or on slippery surfaces.
5. Improved vehicle safcty

3.7.3 Anti-Lock BrakeT

Types:
Anti-lock braking system
or ABS has different types of brakes
based on number of channels
Four Channel: In this all the four used.
wheels have their own individual
on all the four wheels can speed sensors and valves. This
be controlled individually which gives beter
ensures the maximum braking control
cont
Three Channel: Three channel comes with two combination, force.
with thre channcl and three one is three channel with
sensors. four sensors andtheotheron
In three channel and four
sensor system, uses four sensors
front wheels and a common on the each wheel there
valve for the rear wheels. is a separate valve for
each of the
The three channel and three
sensor system there are individual
common valve and sensor sensors and valves
for both of the rear wheel. for both the front wheels
with a
Two Channel: This system
build with four.sensors and
control valve for both of two valves. It uses a speed
the front wheels and the other sensors at each wheel, with one
one for the rear wheels.
One Channel: It has one valve
and one sensor for both
there is a posibility that one of the rear wheels. This system
of the rear wheel will lock, reducing is not very effective becanse as
the effectiveness of brakes.
3.8 Difference between Mechanical
and Pneumatic brake system

Mechanicalbraking
These brake are less powerful.
These brakes are more
powerful and effective
2. These are interconnected
by Mechanical Linkages.
(solid links) These are located
as per chasis design a
interconnected by a pipe through flow. which air is
3. The operator can required
more effort or force.
Less effort or force
is required.
4. These brake have no such application
other than | The
braking. compressor air is used for tyre intlanonau wind

SCreen wiper etc.

Construction is simple.
Complicated in construction.
6 Cost is less.
More costly system.

Teckee

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 Sem-VI) 3-19
Engineering (MSBTE
Automobile le Automobile Control
Hydraulic and Pneumatic Braking System: Systems
Difference betwee
3.6.1
MSBTE: S-15,W-17,W-18
hydrauic
vdraulic bräking system ith pneumatic braking system.
befween
a
Compare S15, W-17,W.-18)
Hydraulic brake system
Sr. No.
2 Pheumatic brakesyster
will get relined of brake fluid leaks out of Brake shoe will not affected
Brake shoes due to leakage of air.
lining.
the brake

Large effort is required to diver to operate the,brake Less effort is required to driver
the to operate
2. brake pedal.
pedal
Brakc fluid is not useful for other
purpose. Air is used for inflate tyre, actuate
3.
steeringetc.
need of
compressor, air filter. Component like compressor air filter
4. No are essential.

Braking is less powerful. Quick braking effect (more powerful)

. Less frictional less as self lubricating. More frictional loss.

Simple in constriction and less moving part. Complicated in construction and more moving
"

1.
part
. No engine power required to run the system. Compressor consume engine power to operate the
sy'stem.

. |Less cost. More costly.

3.9 Comparison of Disc and Drum Brake

1 In disc brakes friction surfaces are directly exposed to the cooling air while in drum type brake, the friction occurs on
the intemal surfaces, from which is disipated only after it passed by conduction through the drunm.

2 In disc brake friction pad are flat while in drum brake friction lining are curve shape.
3.The desiga of disc brake is such that there is no loss of efficiency due to expansion. As in drum brakc system becamie
hol, expansion of a drum of internally friction surface apart, causing loss of effcctive pedal travel. One the other hand
brake dise expansion merely changes the relative position on the friction surfaces slightly without tending to increase
the clearance.

Drum brake

Disc brake

0.1 0.2 0.3 04 0.5 0.6

Coeffient of friction

Fig.3.9.1

FTechTaeuledgi
Pubiltatios
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 Automobile Contr ystens
Automobile Engineering (MSBTE Sem-V) 3-20
aPprOximately 20 g
counterpart-a saving ot being
conventional drum type
pot type disc brakes weighless than the
possible.
than drum brake.
.Disc brakes have better antifade characteristics surfaces can be sho
hown by plotting
changcs in the friction coefficicnt at
the rubbing brake .
6. The sensitivity of a brake to
factor against friction cofficient.
comparcd to drum brake i.e. 1:4. This means the pressure
frictional spot brakc is very less
7. Total arca of pads in
type.
intensity in disc brake is greater than drum MSBTE W-14, S15 W16 S-17.S-18, W-18,.S-19
w-14,S-15,W16,S17S18 N 18S
poiny
between Drum and Disc brake (any ejght
Diferentiate
Drum
brake
St No DiscBrake
Friction lining are curved shape.
Friction pads are flat.
Friction occur internally and heat dissipate by conducion
2. Friction surface directly exposed to air cooling.
and convection.

3. More efficiency. Loss of efficiency.

Light in weight (20 % less) Heavier in weight.

4
. Better and anti-fade characteristics. Poor anti-fade characteristics.

. Frictional area of pad is less. Friction area is more.

3.10 Steering System

MSBTE:S-15
QState the needotsteeringSyste
The steering system allows the driver to guide the moving vehicle
on road and turm it right or left as he desires.
During steering, the movement of the wheel
must be positive and exact and no wheel should slide on the road. Ths
aspect is influenced
by the steering linkage mechanism, tyre
and road conditions and vehicle
suspension system.
In order to maintain proper control throughout
its speed range with safety
bumps and bounce and provide in a straight ahead motion well as during
directional change with as
minimui effort of driver. Such mechanism
is known as steering mechanisn. is uised in a vehice
When a vehicle is moving on a road surface, the relative motion
of pure rolling This condition between the wheels
must be satisfied when and the road surface shoud be ou
the vehicle is moving
3.10.1 Purpose(Requirement) along straight or curved paths.
of Steering System

C What are 17:W-18

the reguirementsot MSBTE: S-14,W-15.S-16,
steering system
OSlateneedotpowersteeing
andexplain generallayout
QWhaare ha r t QenerallayoUtotn
otpowers S16
Listrequirements
ofsteeringsystem?
S
1. The steering mechanism W-18
should be
very accurate
2 It shouldmultiply the turning effort andcasy to
handle.
applied
on the steering
wheelby
the driver.

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 (14SBTE_Sen-V) 3-21
Engjineering Automcbile
Autormohilo Contro Syaterms
certain degrec ircvernible t the shocks on the road surface encountered
shoudbe ito a by the wheel
3. hands. are not
the dri ver 's
transmitted to
iem should have self-rightening
mechanism effct so
that when the driver release
The stcering the steering wheel
4. whoel should try to achicve straight ahcad position.
negotiating a turn, the after

3.10.2 Function of Steering System:

swinging the whecls to the left or right.

It helps in

stability.
2 t provides diretional
3. It helps in tuming the vehicle at the will of the driver.

4. It helps in controlling wear and tear of tyres.

5. t helps in achieving the self-rightening effects.

converts
ft the rotary movement of the steering wheel into an
angular turn of the front wheels.
1. It multiplics the driver effort by leverage to make it easy to turn the
wheel.
8. It absorbs the road shocks thereby preyent them to get transmitted
to the hands of the driver.
3.11 Basic term related to Steering
3.11.1 Steerlng Ratio (Reduction Ratio):

It is defined as the number of turn on the steering

wheel to produce one turn of the
steering gear cross shaft when
pitman arm is attached to it

The Steering ratio varies between 14:1

and 24:1 in case of passenger cars.
It grows with the size of the car, being low
for small, light car.

There are different types of gears

which have variable reduction ratio
by varying the pitch of the worm of cam
is flatter at the centre. so that it

Itislárger for straight ahead while for outer range

it is lower.
The gear ratio can be defined by considering
the turning of cross shaft.
It turns much less than the completing
the rotation in operation.
Therefore, gear ratio is the ratio between
numbers of degrees of rotation of the steering wheel
degrees through which and the numbers of
the cross shaft tums rotates.o
3.11.2 Turning radius:

The turning circle or turning

radius of a vehicle is the radius of smallest circular turn that a vehicle is capable ar when
a vchicle takes a u-turn. depend
It is on the maximum angle of the front wheel can tum and the wbeel base..
The radius of the circle on which
the outside front whecel moves. When the front wheel tum to extreme outer portion is
AnOwn as turning radius. It varies from Sm 8m
to for passenger can and upto I5m for bus and Truck. It is proportional
to wheel base
of the vehicle.
3.11.3 Understeering and Oversteering:
While taking tum,
the centrifugal force acts on the vehicle which produces side thrust.

ntnat force, the plane

achicved by the distortion
of the wheel must make some angle with the direction of motion of vehicle. Thiss
of tyre tread.
Tecaledg
tiess

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 Automobile Control
Sysle
Automobile Engineering (MSBTE Sem-V)_ 3-22 ems
as slip ange. 1his value of slin
taken by the wheel is known pangje
The angle betwoen the whel inclination and the path actors such
load caried by the wheel and other factors such as
:
depend upon amount of side force, the flexibility of
tyre camber

angle and road surface.

front, the vehicle tends to over steer than is
is to
to turn
tum into
When the slip angle is greater at the rear wheel than the
i

the
e
Curve more than the driver intended.
under steer.
When the slip angle is smaller at the rear than the front, the vehicle tends to

The under ster is opposite to over steer and is preferable because corection
by the driver involves rotating the steering
e
wheel a little more in the dircction of turn.

Sip Sip
ange angle,

ineocurve
Under
Cente
Ovorate
Centre
Slip angle greater
Slip angle greater
at rear
tfrort

Fig.3.11.1:Understeer and Oversteer

The over steer reduces driver
effort during cormering and has
advantage while driving along
Uns. road having many twist and
The under steer gives diving
stability especially when
there are strong side winds.
straight roads. The understeer
occurs when front tyre start It is better for fast driving on lng
slipping.
When the slip angle
at front and rear wheel
is same, there is no tendency
neutral straight line. This
is called neutral steer. of the vehicle to move away
from the path of

Slipangle-

.
Centre ofrotation
with slip
angle
=0

(a) Understeer
during turning

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 Sem-VI)
Engineering(MSBTE 3-23
omobile
Automobile
Control Systems

Centre of rotation with slipangle

=0

(6) Over-steer during

turning
Fig. 3.11.2
3.11.4 Basic Components of Steering Linkage:
The ctering linkage, depending on which steering gear
steering wheel steering is used, may consist
column, ball and socket of the inner and outer
joint, draglink or pitman arm, tie rod, tie rod,
drop arm, etc.
.In all type of steering systems, there is a cross shaft in the steering
through a od in the hollow steering column box. Which is operated
and some types of steering by means of steering wheel
gear.
The cross shaft is further connected to drop arrm
a also called pitman arm its
results in the inear motion of the at end. Thus the rotation
drop arm at it's end which itself of steering wheel
is connected through ball
To meet different requirement of different a joint to a link rod.
vehicle different steering linkages
important type steering linkage are having individual variations are used some
direct cross type, center arm steering,
three piece steering, etc.
The steering linkage is adjustable
to berable to vary the toe settingg and perform
necessary to account for tolerance an alignment on the vehicle. This
stack-ups in frame and suspension components, is
such as potholes. component wear and impact damage

() Steering linkage for rigld axle

suspenslon

Q Explainthe working otsteering

MSBTE: S-09
linkagefor ngld axe suspension
S-09

Track rod Steering arm

rod)

Link rod
(Drag link)
Steering box

Drop arm
Steering
column

Steering wheel

Fig. 3.11.3 :Steering linkage for rigid axle suspenslon

Teclanedi
Itiens.

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 Automobile Control Systen
Engineering (MSBTE Sem-VI 3-24
RAutomobile
causesthe turning 1

suspension. The link rod of the front

conventional rigid a
Fig. 3.11.3 shows stecring linkage for a
rod.
wheel through the steering arms and the track socket joint,, it is conside
The component a ball and
connected by ball joint.
The track rod and stecring arms are Tor wear and misadjust
expanding spring compansaies stment
in
joint is such that the
Wcar component. The design of ball

the system. inkage only one wheel is positively

also provided. In this steering roeie
length of the track rod is
A provision for change the
steered.

(b) Steering linkàge for independent

suspenslon
wheels relative
thewheels relati to each other,
regarding the motion of to ken
. In independent suspension, a provision has to be made

the steering geometry correctly at all ime. ck rod. In

actuate the two picce track In this
thie case
e
and a centrally idler arm both
track rods are provided
Fig. 3.11.4 shows two
the wheels are positively steered.

Tont Track rod

Relay rod
Shibade

Track rod
Pitman am
EFvéd to frame
emg box

Steering cotun

3.11.4:Steering linkage for independent

suspension
Fig.
due to
stub axles can move up or down independent of cach other whi
In case of independent suspension, the two ich
ends of the two track and arms is continuously varyng. On account of this a single trast
distance between ball joints
used, the center portion being called the relay rod.
rod cannot be used, instead three track rods are
ger
Relay rod is connected at one end to an idler amm supporied on body structure and to the drop arm of the steering
the other end through ball joints.

The relay rod is restricted to move in horizontal plane only. Movement in verical plane is provided by the outa
portion, viz, the tie rods about the end ball joints, in case of conventional igid axle suspension, the main atle bean
ensures the movement of stub axle in the horizontal plane only.

In this therefore, there is no vertical defiection of the suspension amd hence there is no change in effective traek mi
Iength

3.12 Types of Steering Gear Boxes

Worm and Worm sector/ wheel steering gear

.Wormand Nutsteering gear

Worm and roller type steering
gear
Rack and pinion steering
gear
Recirculated ball type
steering gear

Electronics and Hydraulic powersteering

gear

Tdlin
Pica

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 AutomobileEngineering (MSBTE_Sem-VI) 3-25 Automobile Control Systems
3.12.1
Rack and Pinion Steering Gear

MSETEHS-14WS15, Sal6,S17,WA17. S-18, S-19

ain with sketch working of rack and pinion type steering
gearbox used in Automobile,
With neat skelch, cxplain rking of rack and pinion (14
QWit type steering gear
(W.15
Daw neat labelled sketch of rack and pinion steering gear
(S-16)
neat sketch wnte construconana
Wih working of rack and pinion type steering
system.
Eyolain the working of rack
and pinionypesleering S17,S19
gearboxwith neat sketch Also state
o Explain working of acK and pinion fype steering gear system
ifs advantages (W17
S18)
The rack and pinion gear has become increasingly
popular for today's
smaller cars. It is simpler, more direct acting and
may be straight mechanical or power assisted in
operation.
In small car, this steering is quick and easy.
It provide maximum amount
the roads. There is no darmping out of road feel of road feel as the tyres meet irregularities in
as the tyres meet irregularities
in the roads. "
There is no damping out of road shock
and vibrations compare
to other type of steering system.
As gear ratio is limited to diameter of
steering wheel and pinion
force where as in large vehicle this can
gear so it can be used in small car and operated
be disadvantage hence re-circulating by light
ball type are found in trucks.
In this type of steering gear, a pinion is
mounted at the end
of the steering shaft. The pinion engages
is provided with ball joint at its each with the rack which
end in order to allow for rise
the and fall of wheel.
The rotary motion of the stecring wheel
is transmitted to the pinion.
The circular motion of pinion is converted
into the linear rack movement,
stub axle through ball which is further transmitted to
joint, tie rods the
to
This type of steering gear provides
sufficiently low gear reduction
for car and it is quite suitable even
vehicles if assisted with power. for heavier motor
It occupies very small space and
les number of linkages.
Rack and pinion steering gears used
is in Ambassador and Maruti 800 cars,
Maruti Swift
The rack and pinion gear design are
of two type

Types of rack and pinion

gear deslgn

1. Centre take off rack

2. End take off rack

Fig. C3.6

L Centre take off rack: In this tie rods are connected at the centre of the rack instead
of at the end. It has a large boot
that covers the centre part of the rack and pinioni housing. A slot in the
housing permit the inner tie rod ends
to move
with the rack. This type of design can be mounted high, saving space and reduces
the length of steering column.
2. End take off
rack: In this tie rod is connected at the end of the rack this is less affected by bump steer. When the toe
of wheel changes as they go over the bump, the vehicle is said to have bump steer.

TechKaewledg
P atieas

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 Automobile Control Systems
Automobile Engineering (MSBTE Sem-V) 3-26
Swivel pih
Wish bone
hr

Shb Pri
nde
Te rod

Bal jolnt W Tie rod

Tierod- Boot
Ball ont

Fig. 3.12.1(a):
Rack and Pinion Gear
Steering column

Universal:
joint
Spindle
Flexible-
Steering shaft
Clamps cOupling

Inputshaft
Steering gear

Tie rod

7 steering am

LTie rod L Spindle

Flexible rubber bellows

Fig. 3.12.1(b): Actual Rack and Pinion Gear system

Advantages
1. Stecring is quick and easy

2 No damping to steering wheel

3. Less effort required to drive

4. Operate easily on winding road

5. t provide maximum road feel on inregularities in the road

3.12.2 Recirculating Ball Type Steering Gear:
MSBTE: W16.W-13

Q. Describe with sketch working of recirculating

ball ype steering geat box
aU
liis an improved version of the worm and nut steering gear. It consists of worm at the end or rndAdi
a sici
mounted on worm with two set of balls worm.
in the grooves of the worm, in between the nut and
ousr
he function of ball is to reduce the friction 'between he
the worm and nut. The nut has a number
which mesh with the
teeth on worm wheel sector.
seemng
he drop am is mounted on sector. Which transfer caueste
wneel tum, the balls in the
the motion to steering arns througu
worm groove rolls, causes to nut slides on the worm.
r nut
wheel sector turm
at an angle and actuate
m fthe
wdet

the link rod through drop arm, resung

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 tornobile Engineering
(MSBTE_ Sem-Vi)
3-27
be adjusted
canbc adjuste with the help Automobile
the worm ControlSystems
The endplay of of adjuster nut
provided.
and hence the whecl sector can be positioned along A screw
is also provided
its axis
a by means of

Bal gulda

Ollo Wom

EEitT
Wheel sector

Cross shat

End play aduster

Drop am
Link rod

Fig. 3.12.2:Recirculated ball steering gear

312.3 Necessity and Principle of Power Steering:

MSBTE: S-14, W-14. S-15. S-16, W-16

Explain with neat sketch working of power steering S14, W14
0
0. Nowa day's power steering
issedinmost ofvyehicle.WhySate its advantages S15
Q. State need of power steernng and explain generallayout of power steerin9
(S16
Describe working of power.steering.with sker
W1
With increasingdemand for light control aligning tyre torque for keeping vehicle load acceptable, power steering has
become necessary in most of the vehicle.

In order to reduce the steering wheel turming effort, turn sharp cormer easily, negotiate winding roads and monocurve
the vehicle in confirmed space. The driver can sens and predetermine the approach of front wheel steering resistance to
stabilize the vehicle on turns or wind oad a power steering is used.
The construction of power steering is in such a way so that vehicle may be steered in the usual way when the engine is
not working or any break-down occur in the power source
power steering
The is of two type:

() Integral type
b) Linkage type
n beary duty (dump) trucks and power tractors the effort applied by the driver is inadequate to tum the wheels. In this
aca booster arrangement is incorporated in the steering system.
e booster is set into operation when the steering wheel is turned The ooster then takes over and does most of the
work for
and bydrauic
sg
ns system is called power steering and it uses compressed air, clectrical mechanisms
pressure.

A simplified sketch of Hydraulic

Power
e IS Used on the vast majority of power steering mechanism today.
siering with hydraulic
booster shown in Fig. 3.12.5.
When
thesteering arm.
The gWnecl is turned, the worm turms the sector of the worm wheel and the
arm high and the
turns the road wheel offered to turm the wheels is too
effortapplied by meansof o the drag link. If the resistance

e byt diver to the steering wheel is too weak, then the worm, like a screw in a nut will be displacea
e
ly together with
the distributor slide valve.
TechKneuledgë
Puatatlons

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 Automobile Control Systen
Automobile Engineering (MSBTE Sem-VI) 3-28
Steering wheel
stems
asenoir
OPumVWorm
Distributor
slde valva
Tcheck
valve
Cylinder
Wom
sector

Am
Géarrack Piston
Drag link

Fig.3.12.3:Hydraulic Power Steering

The axial movement of the distributor slide valve in the cylinder will admit oil into the booster cylinder through the
pipe linc.

The piston in the booster cylinder will tam the road wheels via the gear rack, the toothed worn sector, arm and
dra
link. At the same time, the worm sector will act upon the worm and will
hift it together with the distribution slide valve
to its initial position and stop the piston travel in the boost cylinder.

.When the steering wheel is turned in the other direction, the wheels will be turned appropriately in the same
sequence.
The more the steering mechanism and wheels resist turming,
the more the control valve is displaced. Hence, power
assistance is always supplied in proportion
to
the
effort needed to turn the whecls.
3.12.4 Electronic Power Steering
Electronic power steering
or electronic power assisted
steering (EPAS) is comprised of four main parts;
reduction gear, torque sensor,
steering angle sensor and
ECU.
the motor,
In this system a fast acting
electic motor inside the rack
helical groove which function housing supplies the
power assist. The
like a rack teth. The
magnet pinion mesh with the
sensor. and the magnetic sensor
on the pinion shaft
act as a torque

Venicle
speed
Steering sensor
ngle
Sensor

orue
sensor

ucon
Keducton
gear Moto
ECU

Fig.3.124:Electronic
Power
Steering

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 Sem-VI)
Engineering (MSBTE 3-29
nobile
Automobile Control
Systems
collects aformation from the torgquc sensor to neip determine how
ECU information from other much assistance
he also take other info areas such as the is needed by the diver.
modulemay traction control
system in order to get moret
The rcading. a
accuratc
it BCU) calculatcs
(LECU) calculates the assisting power
electronic control unit needed based on
the torque being applied the
The driver, the s wheel position and the vehicle's to
whecl by the speed. The ECU send
the varying curent to
ring
clectronic molor to
fes Stcering gear
rotates a stceri with an applied force that reduces
the torque required from
the driver.
send that data to the motor to push the rack left or right depending upon
module will then the direction of curent
The provide t
t he proper amount of rotation when steering
in order to
Tow

Advantages
pump, hose required.
construction as no hydraulic
required for steering.
effort is
2 Les
consumed only during steering.
Power is
3 resetting the selector switch.
assist can be changed by
Powcr
leakage is totally eliminated.
sProblem of fuid
consumed only while steering.
consumption and CO% emission as energy
A Less fuel

3.13 Steering Geometry

MSBTE: -15
pain toe in and toerouf wihrea
0Statelhe requiremenis.ol steerm
RANAN

firong
DefinitionThe angular relationship.anbrithe
frame 1s knounas steeriTg Eeomet
Necesity:
consequenty to steering
Suspension system can result in changes in wheel orientation relative to the ground and
The transmitted by the
vehicle: When these arise from vertical forces
efects unrelated to those initiated by the driver of the
sprung roll steer and fleribility in the
mass can induce
uT-prung mass they are called as bump steer effects. Roll of the
suspension mechanism can also give rise to compliance steer.
.
case/steering stability, ding
ge vanious factors entering into the front, end geometry
and influencing the steering

qualnty have direct effort on tyre wear. These factors are discussed as under.

Camber
S-17 W-17, W-18. S-19
W-15. S-16. W-16.
MSBTE: S-14, W-14, S-15.

Negativ mber
etern Cambea
Define camberangle
stateøftect
ene camberandits normaly
Apainwieefgeometryampe
the
or the
rear of the vehicle. If
nberis the angle from the front
of the wheel vertical, as viewed camber.
ans in
towards the Pne Telauve to from the vehicle, it has positive
chassis, it has negative camber; ifit leans away
OR
Camber
from front of vehicle.
rovided
may respect to the vertical ixis view
ront
bepositive or negative.
wheel tyre with
Camber is also called as vheel
rake'.
Techaraled
ltatie

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 Automobile Engineering(MSBTE Sem-V) Automobile Control Systems
3-30
Effect

When the whecl is tiltcd outward at the top camber is positive. Because of positive camber, the rolling radius at
utierent points of the tyre tread is different result of which the tyre tends to roll like truncatcd cone about the centre of
rotation, so tyre will wcar more on outside.
Negative camber will causes the wear of tyre more on inside. Initially positive camber is provided to the w v heels
so that
when the vehicle is loaded they automatically come to vettical position.
The tyre life will be maximum when camber angle is zero.
Amount: Camber should not be exceed 2°.
Tyre centre Vertical
ne
Camber

Left
front wheel

King pin

Fig.3.13.1: Camber angle

Significance

During turming the performance

of the suspension system is assume
negative camber angle. to by considering the vehicle operating at asightly
At this the chassis rolls in turning,
wheel is connected to the suspension deflect vertically
the chassis by number of links by some distance. As the
which must rotate
be subject to large camber changesas to allow for the wheel deflecton, the whel can
the suspension moves up
Camber angle alters
and dowm.
the handling characteristic
improves grip when cornering/
of a particular suspension
the vertical plane of the
tuming. This results the
tire rather than through
design; in particular, negalive
tire at a better angle to
the road, transmiting the forcesn
ca
a shearforce across
rubber tire tends to roll
on itself while comering. it. Another reason for negative cambcris that a
tyre had zero camber, reducing The inner edge of the contact
the area of the patch is to lift off of tneg
camber, maximizing contact patch. This effect is compensated for byY aPPapplying negaive
the contact patch area.
provided when the camber For maximum straight-line acceleration, ion will
be
angle is zero the greau
and the tread is flat
on the road.
(b) King pin or Swivel
pin or Steering
axis inclination
S-19
W-15. 5-118
ISBTE: S-09, W-09, S-14. S-15.
Deine KIngpin
incination,included
angleand it
EXplain
thetermKing pininclinati
pain wheelgeometry King
pinincination
Most of the steering
systems have
a kingpin which
is attached to steering knuckle to a support
ering knuckic

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 Automobile Engineering (MSBTE_Sem-V) 3-31
Automobile Control
Systems
Steering
King ph axis inclination
Indinaton

-Upper ball joirt

King
pin

Lower ball joint

wwwwwy
wwww

) King pin inclination (i) Steering Axis Inclination

Fig. 3.13.2

In some later design kingpin is replace by ball and socket joint. In this design, the steering knuckle and kmuckle support
are combined into'a single part. This part is called steering knuckle. No kingpin is used in this case

The stering knuckle is supported at the top and bottom by control arm.

Wheel Wheel Wheel

Kinig pin King pi King pin

wwwwwt ww.w

Tracive Road Tractive Road Road Tractve

forca resistance forca resistanca resistanca| forc

Fig. 3.13.3

Definton of Steering axis lInclination (SAI):

line drawn througn
SAI ángle is an imaginary
* LC 1DWard tilt of the suspension toward the centre
of the vehicle. The
centre of tyre
that run through the
PpCr strut and lower ball joint and another true vertical line
Definition of kingpin (KPI): the vehicle
viewed from the front of
steering axle when
of kingpin or
en tne vertical line and centre the
1s known as kingpin inclination or steering axis
inclination.
value is 5'. It reduces tyre wear
and helps to
provide

The kingpin ranges from 3.5° to 8.5 and its average vehicle is stationary.
"SPau nclination
ind
when the Tech neuledgi
effort particularly
steering stabilit It also reduces steering Catiens

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 3-32
Automobile Engineering (MSBTE Sem-VI)
produee.
when the
whecls are tumed and uces a
Effect: vehicle to rise
causing the
the effect of
Th SWIvel pin inclination has than 15
swivel pin
inclinations greater
noticeable self-centering effect for
to wheel. So as soon
Significance: moves up in relation n
causes the vehicle body st
king pin return the wheel to the
the inclination of tends to
When vehicle takes a tun, weight of the vehicle
turn is complete. The reduces steeing effort paricl
ularkly
as the steering wheel left after the provide steering stability. It also
reduces tyre wear and helps to
ahcad position. It
when the vehicle is stationary.
radius
pin) offset or scrub
Combine angle and Swtvel pin (king
() kingpin centre line. Combine angle is eul
between the wheel centre line and
It is the angle fomed in vertical plane to 10°.
inclination. The combine angle may be 9°
camber plus kingpin or steering axis with the gTDUnd i
patch and intersection of the kingpin
the tyre
The distance between the centre of positive camber or both reduce
scrub radius.
radiys. Kingpin inclination or
caled kingpin offset or scrub
wheel tends to toe-in.
(1 Ifthe scrub radius is negative the
wheel tends to toe-out.
(2) If the scrub radius is positive the
wheel is in straight position.
3) If the scrub radius is zero the steering.
position the steering is called Centre point
Without any tendency toe-in and toe-out: In this
12 mm.
The amount of scrub radius should be upto

Effect
offset, the
swivel-pin offset reduces steering effort because the wheel tends to roll during turning. With zero
The
significant
wheel is steered under these conditions there is
kingpin axis intersects the centre of the tyre contact patch. If the
is hat
tyre scrub at the front and rear of the contact patch leading to a
significant steering effort. The disadvantage of offset

longitudinal forces at the tyre contact patch due to braking, or striking a bump or
potholei transmitted through the stering

mechanism to the steering wheel.

Combined anige

Steering
axis

King pin

wwwwy

Fig. 3.13.4: Combine angle

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 Engineering (MSBTE
Sem-VI)
Automobile 3-33 Automobile Control Systems

(d) Caster
MSBTE:S14, W14 SE151S16/W16 S17. W-17, S-18: S-19

QDefine: Caster. 14515s7s19)

oDefine Negative caster
range of angle
0W-14
(S-16,W 16,W 17)
Define.caster, state eifecis on steering and give approximate
QExplain wheel geometry Caster S19)
angle between the king pin centre line and the vertical, in the plane of the wheel is called caster
angle.
.The
Caster is the slant of the steering axis as viewed from the side of the vehicle.
in some vehicles runs through the centre of the king pin and
The steering axis is the imaginary steering pivot line which
on other runs through the centres of the
upper and lower ball joint.

Caster Vertical

-Front Ieft wheel

King pin

ofFront
car

wwwwwwwiiiii iiiiN
Fig.3.13.5:Caster angle
Caster is positive when the top of the steering axis slants to the rear of the vehicle and negative when it leans to the
front.

When the caster is positive, the projected intersection of the steering axis is ahead of the tyre contact point.

Caster is negative when the top of the steeing axis leans to the front of the vehicle.

The steering axis intersection point is called leading point and the tyre ground contact point is called trailing point.
The positive caster is to provide directional stability. The greater the positive caster, greater is the stabilizing force.
Amount of caster about 3° gives good result.

Significance:.

stabilizing force. On
The positive caster is to provide directional stability. The greater the positive castor, greater is the
.
is raised, i.e. positive castor helps the
the fum for a positive castor the outer side of the vehicle is lower while inner one
centrifugal force in rolling out the vehicle. Negative castor tends to oll in the vehiclei. e. the centrifugal
force is counteract.
stability but effort require for steering and hold the vehicle on
The more positive caster is to provide gives more directional
pulling to one side when brakes are applied and
um increase. Incorrect caster can produce difficulties like hard steering,
range of t 1 degree. 3° gives good result caster tends to
shimmy. Amount óf caster will be 2° to 2.5° with a tolerance

changes the vehicle weight when it is not set at zero.

mled
Nties
PapliEat

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 3-34
Sem-V
Engineering (MSBTE MSBTE S-15. W-18. S.1
FAutomobile

toe out G15 N18

(e) Toe in and

in
following termsToe
Define
geometry Toe in
QExplain wheel

(byToe-out

(a) Toe-in Fig.3.13.6

vek.
front than at the rear
when thee vehicle is
wheels are set closer together at the
which the front
is the amount by
Toe-in
when the vehicle is stationa
onary.
stationary.
be set closer at the rear than the front
which the wheel may t
Toe-out is the amount by the fact that the tyres tend to change theirtnac
counteract
toe-out into a vehicle to
The difference in distance, toe-in or
the road.
when the vehicle is running on to make the wheel wanier m
cause anymore tyre wear. But this toe-out will tend
toe-out will not
An equal amount of comect toe-in causes rapid tyre
wear, vibration and wheel wobble.
therefore toe-in is usually prefered. The
attached to the steering or on the ball joint end dt
provided on all vehicle by track rod
Adjustment of toe-in or toe-out is
the steering arms on the rack and pinion
steering.

Significance:

When the vehicle takes a tum, the inside Wheel moves faster than the outer
wheel because the former has to negotiate an
arc ltter. This action auses the whels to toc-out on turn due to the diference in ter
with shorter radius than the
turning angle. The toe-out on tum practically has no effect on stecring control.

If the vehicle is set up with toe-out, the front wheels are aligned so that slight disturbances cause the wheel par b
assume rolling directions during a tun. If steering angle is set beyond the perfectly centered position which rsut
inner whecl to steer in a tighter turn radius than the outer wheel. Thus, the vehicle will always be trying to enter a t
rather than maintaining a straight line of travel.

Review Questions

Q1 Enlist the Requirements of Brake.

02 Explain power steering

used in automobile.

.3 State the requirement of

steering mechanism.
04 Explain construction
and working with sketch.
(a) Re-circulated ball
type steering gear
box.
) Rack and pinion
steering gear box.

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 mobile Engineering (MSBTE
Sem-V)
3-35

A Dillerenlale
between Automobile
Control
05 brako Systems
Drum and disc
la)
Mechanical and pneumatio brake
b)
Hydraulic and pneumatic brake
c)
wilth their efect of the following:
Define
Q.6
Camber (b) Caster
(a)

(c) Scrub radius

Describe the Brake anti-fade characteristic of brake

Q7
power brakeover Hydraulic
advantages of
Slatea brake.
Q8
working of master cylinder.
Eplain Construction and
09
of tandem cylinder over master cylinder.
Q.10 Siate the advantage

classification of brake on the basis of:

0.11 Give the

Location (b) Construction

(a)

(c)Actuation () Application

Q.12 Explain the working of mechanical brake.

general procedure of Bleeding of Hydraulic Brake.
a13 Descrbe the Significance and
front wheel drive Maruti Swift
014 Explain steering linkage for

Q15 State the function of steering system.

016. Define negative scrub radius and negative camber.

braking system.
and location of unloader valve air
0.17 State the function in

0.18 Explain the working of Antilockbrake system.

Q.19 Define Steering ratio,Turming radius

020 Explain Under steer and over steer

021 Dráw the layout of Electronic power steering.

neat skeieu
and toe out with
of steering geometry and explain toe
in
1 the significance
023 State the significance of camber.

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 Automobilo Enginooring (MSBTE Som-VI) TableofConte

UNITIV 3 Classification of Suspenslon Systomns.

4.4 Function and Roquiroment of

Chaptor 4: Automobilo Suspension, Wheels and Tyres
Indapondont Suspension System.. ************e
4-1 to 4-39
4.5 Advantages of indopondent
Syllabus Suspension Systern. **************** **********t uee

4.1 Automoblle Susponsion Syotom: Function and 4,6 Typos of Front Whool
Roquiromont of Rigid Sunponsion Syston: Basic Torms Indopondont Suspenslons. *********************
s
Rolatod wilh Suponsion Systom: (Jounco, Robound,
4.6.1 Mac-Phorson Strut
Sprung nd Unuprung Woight, Spring Rato, Elastlaity),
Typo Suspension System.. ** *******
Typon and Constructionnl Fonturou of Leal Springs
4.6.2 Wishbone Type Suspension System..
************ 410
A.2 Funotlon and Roquirement of Indopendont Susponsion
Indopendont 4.7 Air Suspension Spring.
Syatem: Advantagon of Front Whool *************seso

Suspontion, Construction and Working of Mac-Pheraon Strut 4.8 Air Suspenslon System. ****************************ans 4-13
Typo, Wiohborno Typo Susponsion system,
4.9 Shock Absorber. ********************* ****************************** 4-14 h

4.3 Shock Absurbors ord Air Suspenslon: Layort, 4.9.1 Tolescopic Shock Absorber....m
Conotruction and Worklingg of Air
*
.415
Suspension, Function and
Typon of Shock Absorbor, Principlo of Hydraulic Shock
4.9.2 Gas Filled Shock Absorbers. 4-16
*
********************1

Alorbor, Construction and Working of Toloscopic Shock 4.10 Wheels, Rims and Tyre. *****************************a****** 4-17
Aboorbor, Conotructional Foniuros and working of Gus Flled
4.110.1 Types of Automobile
Shook Abocrbor
Wheels.. Y*****
.4-18

4.10.2 Necessity and function of Rims

A.4 Whoolo, Rlms and Tyros: Functlon, Necessity and
Roquiremont of Whool, Rirn and Tyres: Types of Wheels,
4..10.3 Requirements of Rims . 421
********** *********************

Rima and Tyros, Constnuction and Working of Different .10.4 Types of Rims, their Construction and Working
Types of Whools, Rims and Tyos.
4.11 yros. ennsennpre *****
*********1********** 422
4.5 Tyro Economy: Considoration in Tyro Tread Deslgn,
4.11.1 Desirable Properties (Requirement)
Foctorn affocting to Tyro Lifo, Tyro Woar and Rotation, Tyre
of Good Tyres.. 422
Doslgnation
4.11.2 Types of Tyres. 4-23
***********************a** ******************
A.6 Whool Alignmont and Bolancing: Purpose of
Wheel
4.12 Comparison of Radial and Cross Ply
lignmont, Procoduro of Whool Allgnmont, Purpose Tyre...
of
4.1313
Whool Balancing, Signficance of Static Tyro Economy: Considerations in Tread Design40
and Dynamic
Balancing. Procoduro for Static and Dynamic
Balancing. 4.13.1 Factors Affecting Tyre Life... *********

4.1 Nood of Suoponslon Systom...

****se 4-1 4.13.2 Types of Tyre Wear. 42
************************************

4.1.1 Functons. *******"**************************"************************* 4.13.3 TyreRotation...

. 4-2 4-34

4.1.2 Roquiromornts of Rigid Susponslon Systern

.
**************
4.14 Specification of Tyre: (Designation of Tyre)..******* 4-35

4.1.3 Basic Torms Rolatod to Susponsion

***************** 4-2 4.15 Wheel Alignment..

4.2 Typos of Loat spring.

********** 4-3 4.15.1 Procedure (Checking) of Wheel Alignment.. 436
4.2.1 Construction and Working of Leaf Spring 4.18 Wheel Balancing
4-9 497
4.2.2 Holpor Springs

.
.4-5 4.16.1 Static Balance of Front .. 439
Wheels.. ***

423 Components of loat spriny 4.16.2 Dynamic Balace of Front Wheels .4-38
***g**q************

Tech Kae
P*llratiaas
 Automobile Suspension,
(a
(4 Wheels and Tyress
Unit- IV

Syllabus System: Basic Tem

of Rigid Suspension erms
Function and Requirement
4.1 Automobile Suspension System:
Unsprung Welght, Spring Rate, Elastich
System: (Jounce, Rebound, Sprung and
Related with Suspension
Leaf Springs.
Types and Constructional Features of
Front Wheel Independent
Suspenslon System: Advantages of
4.2 Function and Requirement of Independent Type Suspension system.
Mac-Pherson Strut Type, Wishbone
Suspension, Construction and Working of
Working of Air Suspension, Function a nd
Air Suspension: Layout, Construction and
4.3 Shock Absorbers and
Construction and Working of Telescope
Types of Shock Absorber, Principle of Hydraulic Shock Absorber, pic

working of Gas Flled Shock Absorber.

Shock Absorber, Constructional Features and
Requirement of Wheel, Rim and Tyres: Types of Whees
4.4 Wheels, Rims and Tyres: Function, Necessity and
of Wheels, Aims and Tyres.
Rims and Tyres, Construction and Working of Different Types
affecting to Tyre Life, Tyre Wear and Rotaion
4.5 Tyre Economy: Consideration in Tyre Tread Design, Factors
Tyre Designation.
of Wheel Alignment, Purpose ot
4.6 Wheel Alignment and Balancing: Purpose of Wheel Alignrnent, Procedure
Dynamic Balancing.
Wheel Balancing, Significance of Static and Dynamic Balancing, Procedure for Static and

4.1 Need of Suspension System

MSBTE:S-14. W-14.S-17/W-18
W-14
Q Wby suspension is necessary inAutomobiles S4
Explajin need of suspension systemnaut obiles
Kplain necesIy oT Suspension sys
In order to provide comfortable ride to the passengers and avoid additional stresses in the vehicle frame.
nor
The vehicle should neither bounce or roll or sway the passengers when cormering pitch when accelermating, bru
or sudden lifting or dropping of the front wheel with respect to rear wheels.

Although some of the road imegularties and inequalities are absorbed by large tyre
ridealso
It is necessary to provide a suspension system for reducing the shocks to passengers and for comiora
reduce additional stresses in the automobile frame and body.
collectively caled a
All the parts which perform the function of isolating the auto are
obile from the road shock
suspension system.

A good suspension should have springiness and damping

The springiness is the elastic resistance to load while

damping is ability of absorbing snocA

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Automobile Engineeing (MSBTE Sem-VI) 4-2
Automobile Suspension,
Wheels and Tyres
4.1.1
Functions

thefunction of sUSpension system.and classify suspension svs

MSBTE: S15
State
1) act
To a$ a Safeguard for the occupants against road shocks and (S15
provide comfort ride.

nTo preserve the stability of the vehicle in olling, pitching, while in motion.
T minimise the effects of stresses due to road shock on
mechanismof a vehícle and
provide cushioning effect.
To provide the required height to body structure as well
as bear the torque and braking
reaction.
9 To keep the body perfecdly in level while travelling over the uneven road.

0 To provide good road holding while driving, cornering and braking.

n tisolate the automobile body from the road shocks which may be in the form
of bounce, pitch, roll or sway.
4.1.2 Requirements of Rigid Suspension System:

MSBTE: W-15. W-16

Q Enistany tour reguirements ofsuspensionš emgnt mobile W-15
Whatis the requirement o suspension
systemn Atütomóbile?
W16
The basic requirements of suspension system are listed below.

It must withstand Greater part of the extra weight of passengers and luggage has to be caried.
There should be have minimum deflection with the loads as well as the torque or turning forces imposed it.
on
It must be maintained wheels in the proper position with respect to road surface.

I should be posidion the axle for minimizing bouncing and associated vibrations to which is liable while moving
of,
braking and conering particularly.

It should be of low initial weight.

nPrevent transmission of 'road noise' to the vehicle body.
requires appropriate isolation in the suspension joints.
I
4.1.3 Basic Terms Related to Suspension:
when it comes across the bump
Jounce: It refers to the bounce or vertical movement of the vehicle suspension upward
or shock in the road.
the opposite direction of jounce. The
Rebound Rebound refers to the movement of the vehicle suspension in
:
rebound, or exteasion. When
and shock absorber is called
AOWward travel of the tyre and wheel hat extends the spring
the spring is deflected, it stores energy

SSprungandUnsprungMasses: design, is broken up into

two partsSprung and
the 'suspension
The Otal mass of a vehicle, for the purpose of
unsprung. main body
these items to the
suspension components that attach
consists of tyres, wheels and
Wgnt unsprung
chassis structure. the wheel ane
all items that move with
weight. In dynamic terms, suspension. The portions
ne Test of the vehicle is sprung bar which are attached to the
absorber and sway
portions of the shock
nis also includes sprung Tecae
tipa"
frame and body are
that are attached to the

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 Tyres
Automobile Suspension, Wheels and
NAutomobile Engineering (MSBTE _Sem-V)_ 4-3
heavier oncs.
with the ground more casily
components can be kept in contact tyre to the surface.
Light springs can retum the
whecls and related assembly must be stopped before the
Motion of the
control.
the less momentum there is to
Therefore, the lighter the components,
handling deteriorates.
weight, the suspension has to work harder and
With greater unspring smoother ride.
thus allows the use of softer springs, which make for a
Low unsprung mass absorbers, thus giving a better
weight can be controlled with springs and shock
With less unsprung weight, more
ridc quality.
handling and steering.
and unsprung weight
adverselyaffect ride,
Resonance duc to the sprung quality,
amplitudes and the lower the ride TOad

unsprung weight, the higher the hop and tramp

The higher the
holding and stability. dyanamic forces
vehicle during the steady aero to

It is defined as the amount of force acts on the

4. Spring rate :
the load is placed onto the spring.
spring, however, remains constant at
compress or deflect a spring. The rate of the
force applied (when it come across the bum)
measures of the deformation of an vehicle body when
It is the
Elasticity :
5.
suspension system.
In automobile it must be constant for

4.2 Types of Leaf spring

springs.
Following are the different types of leaf

1. Seml Eliptical Spring

in front and
Particularly in trucks, semi-elliptical springs are fitted
rear
These are usually used in all the vehicle.
semi-eliptical plate.
axles. The leaf springs are made of steel plates or flat
axle. Semi-
the independent suspension is fitted on the front
But in cars, they are fitted on the rear axle only and
the range of spring action and last for a
lomg
elliptical springs are cheaper and require less repairing. They increase

time.
full elliptical spring and fited wh
2 Quarter Eliptical Spring: This type of spring consists only a quarter portion of the
the frame by the bolt.
qu
3. Three Quarter Eliptical Spring: Three quarter elliptical spring i the combination of semi elliptical and
elliptical springs
One end o
4. Transverse Spring: Transverse spring in just like the semi elliptical spring but inverted in shape.
by the Dos
spring in joined with chassis frame by shackle, and the other end with the axle. It is also fixed with frame

thecentre.
opposiily,
5 Full Eliptical Spring :
Ful eliptical springs are consists of two semi elliptical springs joined together
do not maintain corect axle alignment.
frame
6. Platform Type Spring: Platiorm type springs consist of two semi-elliptical springs. They are fited wit
weight
by shackle at one side and the other side is fitted with an inverted semi eliptical spring, In this arangenu
of the car is divided into three points.

4.2.1 Construction and Working of Leaf Spring:

S-16,S18
MSBTE: S-14,

Descnbe with neat sketch the construction andworking of leat spring

Draw neat labelled sketch of rear leaf spring suspension
and explaD
QDraw neat sketch qf leafspring:Slateitsfunction:
licati

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 (MSBTE_Sem-V)
Engineering 4-4
Autorm
mabile obile Suspension,
Wheelsand Tyres
Al
Semi
clliptica lcaf
dly
springs are widely
used for suspension
in light and heavy commercial
vehicle. In
suspension. car these are used
rear
for lates or flat semi-clliptical plate.
are made of
leaf springs
The c ing over hclical spring is that the ends of the spring may
advantage ofl be guided along the
definite path asit
The structural member in addition to energy absorbing device,
deflecs to act as a
lateral load,ibrake torque, driving thrust and shocks.
spring cary
Thusleaf
plates called blade or laves.
number of semi elliptical
cons ists of
N
curvature or camber so that they tend to straighten under the load
leaves
e are given iinitially
aTe given
The ry in length and are held together
by a bolt passing through the centre acting as a beam of uniform
Theblades
strength.
"U bolts.
to the axle housing by means of
spring is clamped
The leaves has its end formed in the shape of an eye through which the bolts are
leave is known as master
The longest
spring to its support.
passed to secure the
material such as bronze or rubber. The other
shackle provided with bushing of anti-friction
eyes are attached to
The
leaves are
graduated leaves.
trimmed in various forms.
Ieaves, the ends of graduated leaves are
prevent digging in the adjacent
To twisting moment due to presence of stresses
has to withstand vertical bending load, side thrust and
.The master leaf to provide two full length
leaves and rest graduated leaves.
caused by these load so it is usual
that graduated leaves also shear the
intermediate position in the leagth of the spring so
Rebound clips are located at

stresses induced in the full length

leaves when the spring rebound.
(movement about vertical
suspension but they also increase tendency to jaw
provides a soft
Highly cambered spring when brake or accelerate
suddenly.
reduces tendency of the vehicle to dip (pitching),
spring
axis). Flat

Use of longer spring gives soft suspension. frequencies, wich

vibrate at differeat
than the front spring. This causes them to
longer
Generally rear spring are kept
prevent excessive bounce. Shackde-

Frame side member

Spring eye
U bolt -Rear axde
Rubber bush
Master leaf
Cip or stapP
(Rebound cip)
Central bolt

Fig. 4.2.1:Leaf spring

Advantages
separate linkage
without the need for a
tis simple position trailing arms and
andsstrong, acting as a linkage that holds the axle in eliminates the need for
2. Extra location. This
weight and costs axle
pan hard are reduced because of the rear TedKeulel
rod.

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 Automobile Suspension, Wheels and Tyres
Automobile Engineering (MSBTE Sem-VI) 4-5

3. They also control axle damping.

4. It support the weight of the chassis.

centre and wide spring base.
efficiently due to the high rear moment
5. The chassis roll can be controlled more

Disadvantages:
inter-leaf friction between each leaf.
The ride is not so comfortable because of the
the cross weight of the
When the sag is uneven, it can alter
Longer use offspring it tend to lose shape and can sag.
angle.
also change the axle-to-mount
vehicle which can affect the handling slightly. This can

4.2.2 Helper Springs:

MSBTE:W17

OStatehe ctionofhelper spring in leaf sprng

to main leaf springs. These are allow for wide range of
Helper springs are employed on heavy duty vehicle in addition
operation.
loading when the vehicle is lightly loaded, they do not come in

When load on the vehicle increase, they take their share load.
is fixed to the bracket attached to the vehicle
Generally these are located at rear suspension. Both the ends of this spring

frame

Frame- Shacke-

Brackets

E Main spring

Helper spring
U bolt
-Rear axle

Fig. 4.2.2: Helper Spring

Functions:

1. Itis semi elliptical leaf spring without cye at the end and help to share the heavy load with main leaf sping
2. It help to cushion the vehicle and passenger

3. It provide more rigidity to chassis and frame to avoid distortion.

4. It help to store energy on road bump when vehicle in motion.

4.2.3 Components of leaf spring:

1. Spring hanger

The spring hanger attaches to the vehicle frame.

A bolt and rubber bushing attach
the spring ey
As the spring bends the spring eye moves vibration
dampens
spring.
back and forth on the bushing,.
The bushingalso
also
a
Paitati

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 ile
Engineering (MSBTE_Sem-VI) 4-6 Automobile Suspension,
Wheels and iyres
AUO Shackle
5pring
2 MSBTEW17
shackle in leaffspring. W-17)
Ine Tuncton ot
State betwe
the spring
bends, the distance
distance between the two ends changes. The spring shackle is a swinging support that alows
.As
this change.
leafspring
.Function of shackle in
articulation as it 15 a
1 tallow the leaf spring to accommodate the change in length of leaf spring during suspension
integral part of suspension system of leaf spring.

The shackle mount will provide

increase leave rage.
2
3. The axle will move up and down (yawing action) so pinion angle increase.

4. The shackle improve vehicle function by providing ground clearance for larger wheel and tyres.

3.
Rubber bush:

Rubber bushing permits the shackle to swing back and forth. The bushings also absorb vibration and
prevent it from

reaching the vehicle body or frame.

Shock absorber
Spring shackel
Ubolts
ushing
Bumpers

Spring eye
1
Vpushing

Leaf spring
Bushing
Bolt-

Fig. 4.2.3:Parts of Leaf spring

4. Single-leaf spring
plate.,
The single-leaf or tapered plate leaf spring is made of a single

The plate is thick at the center and tapers to the two ends.
multi-leaf spring. However, there are no additional leaves to slide
The single-leaf spring mounts and works same as the
on one another.
elliptical blade together and rebound clip shear the load during
Central bolt and rebound clip: It hold all the semi
braking and shocks.

43 Classification of Suspension Systems_

MSBTE S13:S16

ssy suspenslon system. S1

(S16)
pesoSuSpenson Sy

TechKaouledge
Pbilcatiens

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 Automobile Engineering (MSBTE Sem-VI) Automobile Suspension, Wheels and Tyrea
4-7 yres
The suspension system is classified as:

Types of Suspension System

(1) Conventional or Rigid System

(2) Independent system

(3) Rear end suspension system

(a) Longitudinal leaf spring rear end sUspension

Transverse leaf spring rear end suspension

6)

C) Coil spring rear end suspension

(4) Front end independent suspension

a) Wishbone type or paralel link type

(6) Mac-pherson strut type

o)Verical guide type

H) Trailing link type

(e) Swing half axde type

5) Interconnected suspensions

la) Air or pneumatic suspension

system

H6) Hydro elastic suspension systerm

) Hydrogas suspension system

(6) Selfleveling suspension

system

Fig.C4.1:Classification
of Suspension Systems
The conventional system,
in which the road springs
are attached to a rigid beam axle. Applicabons-
The independent system
in which there is without ay
reaction on the no rigid axle beam
other wheel. and each wheel is free to movev
The suspension
system are againclassified
3. Rear end suspension as:
system
(a) Longitudinal
leaf spring rear
end suspension.
6) Transverse
leafspring
rear end suspension.
c) Coil spring
rear end suspension.
Application
:Motorcycle.

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 (MSBTE_Sem-V) 4-8
omobile Engineering Automobile Suspension, Wheels and Tyres

indepcndent suspension
4Frontcnd link type.
Wishbone type or parallcl
(a)
Applications : Light duty vchicle like swif, wagon R, i 10.
Pherson stt type.

()Vertical guide type.

type.
Trailinglink
(c)Swinghalfaxle type.
suspension system.
5.
Airorpneumatic
buses.
Application: Volvo

Hydroelastic suspension system.

&
Suspension System
44 Function and Hequirement of independent
wheel to follow the road irregularities.
1. Is have ight moving parts help the
The unsprung
weight is low.
2 oscillting.
It absorbs road shocks
or impacts due to bump in road by
3.

Tyres also provides spring cffect, but toa smaller extent

4.
better steering qualities
It set the parameters like
camber, castor angle and king pin inclination for
5.
vertical.
6. Axle should not tilt and wheel remains
stresses in the automobile frame
. It reducing the shocks to passengers and for comfortable ride also reduce additional

and body.
chassis frame.
8. It require more rigid sub-frame or
misalignment of steering geometry with the wear of component.
9. IIrequire more frequent attention on

Advantages of Independent Suspension System

45
wheel movement.
low spring rate (stiffness) enable large
L tmay provide softer suspension, because the
can be moved forward
chassis frame can be placed relatively lower which means engine position
2 In this the engine and
so more space for passenger.
known as the
the chassis and body relative to
that of the wheel and axle is
3. The unsprung weight is low. The weight of
unsprung weight. Hence ride quality is improved.

4. The variation in caster angle is reduced.

increases tyre lite.
The independent suspension reduces the tyre scrub and hence conventonal
deflection as in case of
6. steering geometry is not altered with spring
n case of independent suspension,
accelerating
during braking or
ngid axle suspension where the effect is observable preferred to over steer
understeer conditions, which is always
obtain
"B possible to locate the springs apart enough to
condition.

Disadvantages:

1. The initial cost is high.

more number of bearing
Tcquire more maintenance because of
3. transmited to steering wheel.
unbalance wheel forces are easily
Tech Tneued

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Automobile Enginering (MSEBTE Sem:V) Automobile Suspension, Wheels andTyres
4-9
4.6 Types of Front Wheel Independent Suspensions
Types of front wheel
Independent suspenslons

(1) Mc-Pherson strut type or single

wishbone system

(2) Wishbone type or parallel ink type

r double wishbone fype

(3) Trailing link type

(4) Verical guide type

(5) Swing-half axle type8

Fig.C4.2: Types of front wheel independent suspenslons

4.6.1 Mac-Pherson Strut Type Suspension System:
MSBTE: W-14, S-14. S-15, W-15. S-17. W-17. W-18

With neat sketch explaln the workingot Mac Pherson ype suspensior system
Explain with neat sketch Mac-Pherson ype suspension
systemGve name this ype d
SUSDension syYstem is used Gve any two advantages otit

QDescribe the working of Mac Pherson.strütiype sSUSDension with reat sketch

Q Descnbe construcion of Macpherson suspension system with neat sket
Q. Describe construction of Mac Pherson suspension system
State its ady
A Mac-Pherson, cngineer introduces a single wishbone
with a telescopic strut type independent suspension
system
This system, consist of a telescopic strut type
shock absorber, a single arm and diagonal
a stay.
Body member

-Spring

Shock
absorber

-Strut contalning
shock absorber

-Shub axde

Wish bone am

Fig. 4.6.1: Mac-Pherson Strut

Suspension System
tiets
DIiea

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 Sem-VI)
Aulomobile
Engineering(MSBTE 4-10 Automobile Suspension, Wheels and
Tyres
is fixed to the underside of the cross member of body through
upperendof a stut a flexible mounting and a lower
.The the strut is fastened at the ttom by a joint to the lower wishbone arm.
part of carries the stub axle, on which wheel is mounted.
The lower
pat of the strut also
wheel is transmitted to the lower part of the strut and it turn the
rotary motionofthe stering whole unit
The
oressive coil spring with shock
absorber surround the upper part of the strut which takes care
helical o of the road
A absorbing the shock and
vibration bya protect the vehicle from the stresses transmitted to the body.
Dughs
ughness shocks and
Maruti-zen , Manuti-800, Maruti alto and Maruti swift.
1

Aplications:
App
Advantages

in construction.
1. Itis simple
constant.
Keep wheel camber
2
very easy.
3. Its maintenance is
follow the road iregularities.
moving parts help the wheel to
4 Is light
Disadvantages

1. Increases tyre wear.

Quality of ride depends upon

shock absorber.
2 accurately.
check steering angle
3. Special cquipment is required to

Cannot withstand heavy

load.
4
4.6.2 Wishbone Type Suspension System: MSBTE:S-16. W-16

m with
construction orking of Wishboné type suspension
pain suspen ejis advar
Desco thuicional Wishbone type

It consists of two wishbone arm pivoted to the frame.

length than lower arm.
The upper wishbone arm is shorter in
reduces the tyre wear.
constant, so avoid the tyre scrub and thus
track
This help to keep the wheel
. A small change in the camber does occur
with such arrangement.

suspension system is most popular.

The wishbone type independent member.
the lower wishbone and underside of the cross tne
The coil spring is located in between through which it goes to
member to the coil spring
body and the cross
u weight of vehicle is transmitted from the
lower wishbone member.
Wheel

Upper wishbone am
Cross am

Spring

Damper
Lower wishbone anm

system edlaiedge
4.6.2:Wishbonesuspension
PuDDiCatieas
Fig.

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 Automobile Suspension,Wheels
Wheels
andTyrea
Automobile Engineering (MSBTE Sem-VIl 4-11
cross member and too lower
lo wishbone men
the coil spring and is attached
to the
A shock absorber is placed inside transmit the vehicle load
adtothespring,bu
position the wheels and
Because of 'V' shape of
am, the wishbones not only
these also resist acceleration, braking
and side forces. upper arm (control a
move up, the lower ind movea
tended to
come across a bump and wheel is vibralions Set up in the coil spri
When the vehicle (damper) damps
the dueto
is compressed so shock absorber
up and the coil spring

road imegularities.

Advantages of Wishbone suspenslons wear.

scnub, reduces tye
constant, so it avoid tyre uneven surface or on the
this type wheel trackis stable on holeor
In vechicle is
independent, so vehicle is
Right and left side suspension of
2 to
transmts the vehicle load the s
digs.
positions the whels and
arm, the wishbone not only
Because of V shapeof
braking and side forces. better vehicle stability
also resists accleration, ground clearance and
Mac-Pherson, so less
compared to
requires less vertical spae
4t
5) Low sping rate.
deflection.
altering with spring
6) Steering geometry is not
Suspension
Suspension and Independent
Difference between Rigid Axle
ependent suspension
Rigid axle suspënsi
Sr There is no rigid axle
beam.
rigid beam axle.
The spring is attached to
without any Teaction
Each wheel move vertically
vertically having reaction |
2. Wheels moves (deflect) not tile and wheel remaine
other wheel. Or Axle does
on other wheel. Or
Axle tile and wheel no longer
vertical.
remains vertical.

Used for light vchicle like car at front

3. Used for heavy vehicle like, truck.

Less tyre scrub, increases tyre life.

More tyre scrub, reduces tyre life.

Steering geometry not alter.

5. Steering geometry alter/change.

spring rate
6. Provide slightly rigid suspension due to higher| Provide softer suspension due to low
spring rate. (stifness)

7 Wheels may wobble. No chances of wheel wobble.

8 Road adhesion less. Road adhesion more.

4.7 Air Suspension Spring

A volume of air enclosed either in a cylinder fitted with a piston or in a flerible bellows can be used as sprng
Under static load the air is compressed to a predetermined
pressure and subsequently motion 0r ue g
eith
increases and decreases the pressure and consequently
increases or decreases the force acting on pistOn.
Air springs are fairly widely employed
on vehicle whose laden and unladen
weights differ greauy.

91latiat

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 Engineering (MSBTE Sem-VI) 4-12 Automobile Suspension, Wheels and 1yres
Automobile
suspension
Advantages of air
height from road surface.
maintains constant road
n I with increases in deflection.
stifiness of systemincreases
(2) The
Improve
slandarddoof ride comfort and reduces noise.
) used are cxplain below,
common type of air suspension springs
The
Type of air suspension springs

(a) Bellowtype air springg

(b) Piston type air spring

Flg. C4.3:Types of Air Suspension Springs

Bellow type alr spring

()
This spring consist of rubber bellow which is generally circular in cross section. The bellow
has two convolutions for
proper
functioning. The constructional details are shown in the simplifed sketch. The type of spring is a good
replacement of coil spring.

Frame
Alr

Flexible bellow

Lower withbone

Fig. 4.7.1:Bellow type air spring

) Piston type alr spring

type spring consists of a metal air container in the form of an inverted drum. The
drum is fixed to the frame and
hs proof a seal is provided by a flexible
the sliding piston is attached to the lower wishbone. For making the system leak
uaphragm. The diaphragm is secured at its outer circumference to the lip of the
drum and its centre to the piston as
shown in Fig. 4.7.2.
Metal container
Frame
member Flexible
diaphragm

Piston

Lower
withbone

Fig. 4.72: Plston type air spring

Kamledga
Tech
B7
YPblltatins

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 Automobile Suspension, Wheelsand
and7
Tyres
Automobile Engineering (MSBTE Sem-VI) 4-13

4.8 Air Suspenslon System MSBTE:W-15,S-16S-18.

WA

suspension with neat sketch. W15

OEXplain construction of alr
suspenslon system and name the com
QSketchlayout of an air
Howair suspension system works? Draw the layoul

aExplain air suspension with skétch

prove the
to improye riding comfort
the riding
employed in some tounst vehicles comf of
Now-a-days pneumatic suspension systems are the

passcnger.
Tfitting Alr bag Rear leveling
Check valve Filler
r bag valve
Alr Pressure
recelver regulator

Leveling
Tcheck valve
valve

Compressor

T httng-
A Tcheck valve
Air bag

Solenoid Air bag

Leveling valve'

Fig. 4.8.1a): Air suspension system

A line diagram of the air suspension system with air shown in Fig. 48.1(). I consists of four air bags as shown in
Fig 4.8.1b).
The elastic element consists of housing, diaphragm with suitable air inlet and piston group. The housing is linked with
the frame (sprung mass). The housing contains the piston group which is linked with unsprung mass (rear
and front
axle).

The housing and piston group are conmected by a metallic diaphragm for better sealing and reduce friction between
to
the members of clastic clements.

Each air bag is filled with compressed air. The sketch of air bag shown in Fig. 4.8.1(b).

The component of air suspension system are air filter,

compressor, air reservoir, relief valve, pressure regulator,
solenoid valve, levelling valve and
T check valve.
An air compressor is mounted on the vehicle frame supplies
high pressure air into the reservoir. The compressor sucs
the air from atmosphere through air filter.

The pressure in the reservoir is maintained

at about 20 kg/cm.

Housing

-
Fig.4.8.1b): Air bag
-Dlaphragm

Piston group

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 Automobile Engineering (MSBTE Sem-VI) 4-14 Automobile Suspension, Wheels and
Tyres

The compresscd air in the air bags support the weight

of vehicle whenever vehicle come across the bump of ne 0a
surface, the air inthe air bag compresse and absorbs the shocks.

Airis admitted into the four air bags through two circuits. In one circuit a pressure reduced
to 12 kg/cm" by pressure
regulator.

This pressure is kept in air bag through levelling valve if the

presure in one of the bag is low, the levelling arm moves
nd air is admitted into low pressure air bag through
inlet valve.
The outer circuit has air pressure of 20 kgf/cm". This circuit
pressure is used for additional loading of vehicle.
This can be achicved by special regulator, which keeps
the same distance between wheel and
frame under various loads.
This circuit maintain the vehicle level constant in
loadedor unloaded condition.
For this situation, the air at 20 kgflcm' pressure is admitted
into theleveling valve through solenoid
Also the air is quickly released by levelling
valve
valve whenever load decreased
is from coresponding air bag. This lowers
the air bag and hence the vehicle to the proper
level.
Advantages

1. Constant frequency of vibration.

2. Highly smooth run due to low rigidity.

3. Provide constant body height

under all static load taken
by elastic element.
4. Avoid change in head lamp alignment
due to varying load.
5. Longer service life.

Disadvantages

1. Complicated in design.

2 System is more costly.

3.. Risk ofbreakdown.
4. Freezing of moisture in air in cold weather.
5. Greater maintenance required.

4.9 Shock Absorber

For providing comfortable ride to the passengers and driver as well as reduce additional
stresses to vehicle frame. It is
necessary to provide a proper device in the suspension system for damping
out the effect of rmad imegularities, A
vehicle must be roll or bounce or sway during turming on good road condition.

The springing device must be a compromise betwen flexibility and stifiness. If it is igid, it
wil not absorb the shock
efficiently and if it is more flexible it will continue to bounce or vibrate cven afñter the bump has passed.

In leaf spring damping is provided due to friction but because of uncertainty in lubrication, friction between blade or
leaves vaies its damping characteristics due to this reason an adional damper (shock absorter) must be provided

The shock absorber or damper is a device which absorb shock energy by damping and dissipate into heat. So it serve to
control ampitude and frequency of bouncing. It cannot suppart weight and has zero resilience.
Thiere are many types of shock absorber operating on friction, on compressed air and hydraulically.
present.
The hydraulic shock absorber is the only type in common use at
restricting orifices as the shock absorber is operated by
The hydraulic shock absorber contain fluid that forces through
spring flexure.

le
Platloss

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 Engineering (MSBTE Sem-VI) Automobile Suspension,
Automobile 4-15 heels
W and Tyres
Principle of Hydraulic Shock Absorber

.When a fluid forces through restricting or small orifices it develop the resistance to the movement of the
luid
ft.
through the
the restricting orifices by absorbing shock energy of damping and control amplitude and frequency of bouncing
dissipate into heat.
h
and
of
It cannot support weight and has zero resilience. This effect quickly damped and spring oscillation
lation damping a

proportional to square of the speed. is

4.9.1 Telescopic Shock Absorber:
MSBTE:W-14, S-15,S-16:W-16,
W-17,S-18,S
Q. Explain the working of télescopic shox apeofter with neat ske
W44, SA8
Q.Describe with neat sketchwonking.ot telescopio shock
S15
Drawlabelled neat sketch.of teleéscopictype shock absorbe
Q Deschbe telescopic shock absorberwith sketc 15
0EXplain with neatsketch
Scopic shiockabsorber
Skelchtelescopic shock absorber and label ma
V-17

Construction

It consist of a cylinder to which head is welded

The head is screwed into the top end of the outer tube.
To the bottom end of the outer tube is welded with a pressed stecl
cap and eye or ring. This eye is connected to wheel
axle.
The piston slides inside the cylinder. This piston is secured to the piston
rod which at its upper end has an eye welded to
it. With this eye, the piston rod is attached to the frame of the vehicle
the outside part of the piston rod is protected by a
dust shield (cover) which is welded to the fixing eye.

A gland prevents oil leakage from where the piston rod passes through
the head.
The gland consist of a piston rod, oil seal, oil seal gasket, scal retainer,
oil seal spring and oil seal cup.
Any fluid scraped off by the gland packing passes down drain
a hole to the reservoir space between the cylinder and
outer tube.

The piston has two concentric rings of holes drilled through

it.
The outer ring of hole is covered at the top by a disc valve which
is held down by a star shape disc spring.
The inner ring hole is covered by disc valve from bottom by
the coil spring.
There is a foot valve assembly at the bottom of the cylinder.
The foot valve assembly is similar to that piston assu
sembly,

except that the lower disc valve which covers the inner
ring of holes is held up by a disc valve spring u
spring.

Bolh ends of the cylinder are completely filled by a

mixture of 609% transformer oil and 40% nurbine oil nd
the gp
pace

between the tube and cylinder.

Working:
be
When a vehicle come across the bump, piston nust
the bottom eye is moved upwards, then the fluid below the
displaced to the top
side of the piston.

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 (MSBTE_Sem-V) 4-16
AulomobileEngineenng Automo
A lluidwill pass through the outer ring of hole in the piston = Suspension
Wheels and
Tyres
by lifting the
The the piston is less duc to piston rod.
p disc against
the disc spring,
nlume above But the
bottom of the piston
such, fluid from the pet displaced through
As spacc betwecn the cylinder and outer
inner ing
of holes
entcr the rescvoir tube. in the foot valve
.Uppereye and

Piston rod
Gland

Head

Disc sping
Top discvalve
Piston

Coil spring
Outer tube
Bottom disc valve
Cylinder
Foot valve

Steelcap
with eye

Fig. 4.9.1:Telescopic
shockabsorber
So the fluid level in the reservoir
space will rise.
.The pressure set up in
the system will depend
upon the size of the passage
This will depend on open by valve in the piston
the square of the speed and foot valve.
at which the cylinder is moved
upward.
When the cylinder
moves downward, Fluid will
inner ring of hole
be displaced from the upper end of
in the piston by opening the cylinder to lower end through
the lower disc valve against coil the
spring
Because of the volume of the piston
rod that leaves the cylinder,
cylinder from the the fluid will be drawn into
reservoir space through the lower end ofthe
the outer ring of hole in the foot valve.
provide damping. This passing of fluid through opening

4.9.2 Gas Filled Shock Absorbers:

9as filled shock absorbers

work along the same principle as a conventional
gas cushion hydraulic shock absorber but also havea
that be compressed, therefore
creating space for the compressed oil.
De gas filled shock-ups
can be easily differentiated by 'Canister which holds the nitrogen gas inside
the conventional and atached to
spring loaded shock absorber.
0 canister is used to be filled with pressurized
Nitrogen gas, which further act as reservoir for both oil and Nítrogen
0e role of the Nitrogen gas is to keep the damping oil pressurized so that the gas molecules present in the oil
LIN bonded with the oil molecules and must not get loosen to bubbles/foam and hence prevent the Cavitation.
fom
Dgpston separates oil and gas, thus preventing hem from mixing. If the oil is displaced when the spring is
pressed, the piston compresses the gas cushion. When the spring then extends, the gas pushes the oil back, similar
aspmng. The gas pressure is very high and ensures that even the smallest movements are damped.

Techaaledgi
Pbilcatieas

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 Tyres
Automobile Suspension, Wheels and
Engineering (MSBTE Sem-V) 4-17
Automobile
Monotube Twin tube

Ol Gas bag

Floatng- Oil
piston

Pressure-
93
Absorber
Fig. 4.9.2: Gas Filled Shock

(a) Single cylinder or mono tube shock absorber

contains a
absorber, the shocks components are
contained within one tube. A mono-tube system
Ina mono-tube shock
gas. The construction
cylinder you would finda piston valve, oil and
shell case which works as a cylinder. Within that
mono-tube does also include some diferences compared to
the twin-tube design.
ofa
separates the oil chamber from the gas chamber within the shell case
A mono-tube design utilizes a free piston which
completely separated. As temperature increases, oil is able to
Air is not able to penetrate the oil or gas since they are
release heat with less effort.L

It has zero restrictions on installation angles and Less chance of cavitation.

Disadvantage

More expensive and high pressured gas creates a higher amount of stress on seals which can cause mone friction

(b) Twin-Tube

In a twin-tube shock absorber there are two cylinders. In one cylinder is placed inside the shell case and the second
cylinder contains the piston valve which moves up and down within this second cylinder known as the "inner cylinder".
With a twin-tube desiga, there is no piston or barier between the oil chamber and gas chamber.

Advantage of this is Unlike the inverted design, friction can be stopped. Extemal damage to the shell case does n
effect the shock absorber. Low gas pressure reduces stress on seals and also keeps firiction to a minimum.

Disadvantage of this Oil capacity is reducod in comparison to the mono-tube. Low Pressure- Generally very Sof

4.10 Wheels, Rims and Tyre

Introduction

The wheel and tyre assembly is the last member in

the drive line of transmission system. Wheels are connc
Tear axle,

As the rear axle rotates, the wheel also

rotate and vehicle moves on the road. The wheel assembiy 1s c
disc or spoke,
im, tyre and tube.
duing
The main function of wheel is to support Torce,
the load of the vehicle and passengers and to TeSis
turning called lateral load.
tractve
The wheel alsotransmitengine as
driving torque and braking
torque to the tyre while dnVIg
led
load.

TadL
Publtati.

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 _Sem-VI) 4-18
(MSBTE utomobile
Engineening
Autornabile Suspension,
heels andTyres
Wheel
Functionof
a) following functions
perform the
whecl must
The
the load
iicle, brake system mounting and
Ishould support the passengers.
1.
force, during turning called lateral load
shonld resisttheside
2 I torque and braking torque
also transmit engine driving totthe tyre while driving
The whecl
3. and braking
tractive load. called as
system of the vehicle.
4. It assists the steering

5. Ishould absorb the shock caused by road iregularities.

)Necesaity and Requirements of Wheel

To perform the above
functions, the wheel must be,

1. It should be strong enough to withstand the weight of the vehicle.

2 Ishould be perfectly balanced statically and dynamically.

3. i should be light in weight and easily remarkable.
4. It should be able to grip the road surface.

5. It should not detcriorates with weather condition

and age (cracking, corosion).
4.10.1 Types of Automobile Wheels

Three main types of wheels

are in use today:

Types of automoblle
wheels

1) Pressed steel disc wheel

(2) Wire or spoke wheels

(3) Light alloy casting wheels

Fig.C44:Types of Automobile Wheels

aConstruction andworking
of pressed steel disc wheel

MSBTEW16

ea skejC W16
Now-a-days these wheels
are widely usedfor cars.
The
are light, strong,
cheap and resistant to accidental damage.
PEOT Wheel consists of two
parts, namely rim and the disc member welded togetnet.
Whenthebeadof
the tyre is resting the well, edge of the rim.
in is possible to pass the tyre over the oppasite
t
0 seat of the rim where the beads are forced up the taper to
Wedon tyre rests has 5 to 15° taper so as the tyre is inflated, the
BNEa
wedge fit with tubeless tyre, the taper
helps to make a good seau

Tec armledg
tisss

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 Automobile Suspension,
Wheal
4-19
Automobile Engineering (MSBTE Sem-v Rim
Well
Holo for
valve
Disc
Holes for
cooling

-Cover

Holes for
mouning

Holes for
cooling

Rim widh
Fig. 4.10.1:Pressed steel wheel disc

or five bolt spaced equally ina circle

around the
hub flanpe
ges.
whecls are secured to the axle by four
The
wheel disc to allow the air to pass to the inner side for better coolino
Some slots are provided in the brake dma
tube valve.
inside. A hole in the rim serves to accommodate

A whecdl having
constructed in two parts which when fastened together combines to form a rim having two fixed
ixedflamges
called a divided wheel. i
)Wire or spoke wheels

These whecls are lightcr, stronger and s y.

.It consists of a separate hub which is atached to rim through number of wires called spokes. These spokes
ae me
in a complicated criss cross fashion in all the three plane.

The component of vehicle weight in the direction of spokes above hub is sustained by these spokes in tension. T
braking and driving torqve are taken by spokes.

The side forces during comering are takea by the spokes forming triangular
arrangement.
The initial tension in the spokes can be adjusted by screw nipples
which also serve to secure the spokes to the
in
The hub is provided with internal spline to corresponding
spline on axle shaft.
Rim

Hub

Spokes
Fig. 4.10.2:Spoked
wheel

Tdlan

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 Sem-V)
Automobile
Engineering(MSBTE +20 Automobile Suspension,
Wheels and Tyres
Advantages
light weight and have high strength.
hese are
1.
tprovidesotfer cooling of the brake drum due to better air flow around the brake drum and heat dissipated
capacity.
2 for changing thewheel as only one nut has to be opened
is verycasy
3. It
Disadvantages

difficult to clean.
1.
These are
loose in service.
Spokes tend to work
2.
hole for nipples, it is not possible to fit tubeless tyre.
3. As rimhas a Rim
are expensive due to complicate construction.
in
These
Alloy Wheel
)Cast Light
Cast alloy wheels
are made from casting of light alloy of aluminium

or magnesium.
have wider rims and radial nbs
which also acts as an angled
They
and also reduce noise Hub
spokes to provide strength and air circulation
and vibration.
are provides stability during cornering.
.Wider rims
Stove cnameling of alloy improve appearance and provide
corosion resistant property.
Cast whecls are generally used for
car while forged wheels are
preferred for heavy vehicles.
stiffness
can be used which improve the
Heavier section of wheeldistribution. Fig. 4.10.3: Light cast alloy
wheel
and result in better stress

Advantages
vehicle.
reduces unsprung weight of
1. These are lighter in weight which action, provide better
brake drum
during braking
which helps in heat dissipation
2. These are better conductor of heat
cooling

3. It improves stability on comering. capacity.

shock absorption
by better
and fatigue strength their
* These have high impact

Disadvantages
maintain close tolerance.
precision machining to
1 gner manufacturing cost because of should be povided over it.
protective coating
resistance to comosion hence
Foor
4.10.2 Necessity and function of Rims
vehicleis moving
when the
unprovide leverage and reduce friction
roadis. leverage, Rim
The rim works is to rotate round the tyre passenger vehicle. provide
mmercial and order to
automobile for pavement in
Theseare essential for all and
by vehicle
the weight impacted
The s ze rim is dependent of
of BTecaeuledgë

dclermine performance of ride comfort. atlens

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 Automobile Engineering (MSBTE Sem-VI) 4-21 Automobile
ension,
Wheels
Sizc of rim affcct braking, handling, acccleration, alignment and specdomcter calibration a Tyree
4.10.3 Requirements of Rims

It should have static strength.

It must have fatigue strength.

It must passess impact strength.

It must deform under alltype of load.

4.10.4 Types of Rims, their Construction and Working:

MSBTE:S14AV15.S.a

a State the types ofrims Drawany one type of.nm and write its construdti VI-A

e IStthe various types of rims üsed in automobiles and draW.neat sketchof any
Explain the ypes of WheeFims

Rim is well type of structure in which the tyre is contained.

The rims are gencrally of two types:

(1) Drop centre rim. (2) Flat base rim.

Drop centre rims ane generally used in two wheeler where as flat base rims are used in commercial vehicla i

made of steel or aluminum.

Also rim again classified into flat base three piece rim, semi drop centre and iat base divided type.
For ear
yre,wel
base or drop centre is the common tyre.

The tyre is pressed into the racess of the drop centre well for levcling in opposite sideover
o
the rim ílange. Aslight
is of 5P provided for riding up the bead due to air pressure in the tyre. t
Flat base three piece rim is a detachable flange rim. It is used vith stiff and heavy beads tyre fitted
on heavw whi
The flange is beld in position by a split lock ring similar to larger circlip. The lock ring may
be removed ater
poi ing
the flange toward the tyres.

Semi drop centre rim is a two piece rim. It is compromises between

well base and flat base rim. It is suitable for
vehicle. lit
Its removal is simplified by a split, detachable flange while the tyre
is locked to the rim by a slight taper, when the
tye
is removed the slight well may be used.
Flange

Well

Drop centre rim Semi-Drop centre

rim
rLoose
flange rLoose flange

(a) Two Piece

Fig. 4.104:Section (b) Three plece

of rim

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 Sem-Vi)
Engineening (MSBTE 4-22 mobile Suspension,
Automo ile Wheek and Tyres
di'vided sed mainly in military vehicle. Iit is made in two halves which
base arcbolted
Flat together by
adjacent to the
rim. aring
ofnut these nuts should never be moved.
changing wheel
;

For influenced by
diamcter is
wheel rim
The vehicle,
and weight of the
The size
1.
clearancc and
Theground
2 reguired for the brakes and
suspension components etc.
3. Space

4.11 Tyres
Functlons
Necessityand
link with road and vehicle.
necessary for safe driving as they are
Tyresare
illustrated in Fig. 4.11.1. A tyre is made from rubberized fabic piles over arubber liner
t's of the tyre are
are wrapped around a wire bead, which holds the tyre to the wheel rim.
the edees of the piles
compound tread and ditterent rubber a compound for the side walls. The tyre
.The fabric piles are covered with a rubbrinto a single unit and fom the tread design.
mould to vulcanize the parts
is cured in a
provided with an automobile wheel against shock.
Atyre is a cushion
must be large and strong to
support the load they are expected to cary.
.Tyre
tractive force on accelerating, comering and braking,
.They absorb shocks from road iregularities. They must develop
transmits driving and braking forces of the road.
It
stecring.
Provides comering power for smooth
Maintain steering and directional control.
4.11.1 Desirable Properties (Requirement) of Good
Tyres:
Propertles (requlrement)
of good tyres

1. Load carrying

2. Cushioning

3. Unifom wear

Balancing

5. Non skidding

6. Fuel or power consumption

Noise

Fig. C4.5: Properties of Good Tyres

1. Load
carrying
be strong to carry the vehicle load and also
altermate stress set
up
n cae
danage must
edlaetedgi
iltatisss

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 Automobile Suspension, Wheelo
Automobilo Engineering (MSSTE Sem VI) 4-23 andTyres
set up Dy tne road surface ane
vibration, shocks and impacts provide
Cushioning should be flexible to absorb
:II passengers.
Cushioning effect. So it must provide comfortable ride to
circumfcrence to provide a long nie.
niorm wear: Tyre must wear uniformly over its outer steeri
well as dyanamically. It
must respond accurately toto steering
: It must be balance statically as withou
alancing
deflcction by the ridge on the road.
all weathers condition providing gip
grin for
skidding: It should not skid
or slip on the road surface in traction,
Non
Comering, accclerating and braking without overheating.
. it must coisume minimum fuel and powe.
Fuel or power consumption: During rolling on road surface, to getfue
economy.

Noise :t must create minimum noise while rolling on road surface.

4.11.2 Types of Tyres:

In general, the tyres are clasified in two type:

Types of tyres

(a) Solid tyre

L6) Pneumatic or air fild tyre

1.Onthe basis of pressure and volume

H ) High pressure tyre

(i) Conventional tyre

(i) Super cushion tyre

H2.On the basis of construction

H) Tube tyre

.) Tubeless tyre

3.Carcass ypes
tyre

(a) Cross plytyre

H) Radial ply tyre

(c) Belled bias tyre

(a) Solid tyre: These
Fig.C4.6:Types
of Tyres
are oflimited use specially
6)Pneumatic or in industral applications.
air filled tyre
classified as : In this type
below. an air is acts
as a cushioning
1.
medium confined
On the basis of
pressure in an inner ubc. 1
and volume
)High pressure
tyre (Pressunre
Gi) Conventional upto4.2 Kg/cm)
tyze (Pressure
)Supercushiontyre range 1.68
Kgcm to2.8
(Pressure
range 1.4Kg/cm
Kgcm)
tol.68Kg/cm)

Tdla
icat

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 (MSBTE Sem-VI)
tomobile Engineering 4-24
A On the
basis of construction
Automobile Suspension,
Wheels and Tyres
2
)Tubetyre i) Tubeless tyre

Carcasstypes tyre:
3.
(b) Radial ply tyre
(Cross ply tyre
(C) Belted bias tyre

Tube Tyre
0
It is difional tyre. It encloses a tube in wnich air 1s forced to a high
pressure as a cushioning
emanufacturerd from ditferent parts medium.
ty that are moulded together
to form a complete structure. The
parts of tyre
are

) Liner (i) Tread layer

(Gi) Cord and piles (iv) Bead or rib

() Side wall (vi) Outer rubber covering.

Casing cushicn
Tread pattem
Tread nubber
Breakers

Undertread
Shoulder
Tube
Crown
Plies

-Rubber
Side wall

Filers
Chafers
Bead cindt-
Bead core
Heel of bead-
Rim
Flap
LValve
Bead seat
Toe of bead

(tube) tyre
Fig. 4.11.1::Cross section of a truck
vulcanization process in
is manufactured by
carcass or inner casing. The tyre
The liner and plies form together called as
form and characteristics.
which rubber is heated under pressure to obtain required

(1) Carcass construction and the

backbone of the tyre
the tyre. The carcass forms the
horseshoe-shaped inner lining of
LS 1S a
cord piles
tread, bead and walls all are moulded on to these overlapping plies, consist of
paralel
made from
wall rubber. It is
tyre without side
prvides strength and body to the a layer of rubber.
rayon, nylon, fiber glass, polyester, embedded in pressure acts evenly against
the intenor
rd of walls. Air
bounded to the side
are wound around the beads and
Sends
surface producing tension in the carcass.
the vehicle. The outer
rubber covering is moulded
weight of
and resist the
puEsSure carcass support
around the carcass.
the tyTe
number of plies in Kavualedge

ne ply rating indicate the approximate

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 Automo SuSpension,Whees
wheel
andyTea
4-25
(MSBTE
Sem-VI)
Engineering
Automobile
carcass.
side of the
(2) Liner
rubher on inncr
light laycr of
Liner is a thin air wheel rim. It hastheiggdäity
on to the
centralizes the cover and
(3) Bead locates and
tyre and
the inner edge ofthe
toms bead.
hisstrength required to support
the carcass.
circumfcentially
througlh the
wrapped with a fabric
moulded wires are
achicve this cndless wire core
is
the whecl im and the hold to
To fit around
stcel wires. These are
a bundle of
thin wheel rin
16 protect from leaving the By use
stretching and of
them. from
prevent the tyre
in nubber to
are embedded
These strength of bead
increascs.
heavicr gauge wire the
working ife
holding ability and
(4) Tread gripping, road
considerably influences the tyre's 1s
groove provide
ve to provide :
part of tyre design rolls. The tread rubber marimum
isa road surface when
the wheel
the vehicle on minimize noise.
helps to nun avoiding skidding, rigidity.
fnctional force giving good
traction and additional stability and
which give
circumferentially on outside
to compound of high resiet
stance
chamber is provided changes or convert to
Some separate piece of soft rubber which
assembled in a
The tread are
vulcanization.
wcar after

(5) Breaker
breaker.
are refered to as
two top plies of the tyre
The other plies.
are widely spaced as compared to
They from the road.
plices helps in spreading the shocks recived
These
(6) Side wallI
carcass between the
bead and the tyre tread.
covering of the
constitutes the outside nubber
This and the stiffness of the
tyre during deflection depends on the
thickme
provided to the carcass
The amount of protection
of side wall
different grade rubber. The
rubber has quality to absorb road sthock and
the tread and made of
It connects the bead to
protect cord and piles.
used is relatively porous in nature.
side walls are thinner and the rubber
The
which rolls on the rvad is made of synthetic
rubber and is called tread. At the inner edg
The outer portion of the tyre
steel wires.
beads are formed by reinforcing with

i) Tubeless Tyre
MSBTE: 9-18. W-18.S-19

Describe tubeless tyre withneatsketch

Stateadvantages and disadvantages of1ubeless yre

Tubeless tyre is a advance version of conventional tube tyre.

The basic difference is that tubeless tyre does not enclose a separate inner tube. In this type of tyre there 1s a spea
relaining bead arrangement.

This type of tyre is directly mounted on the rim.

.The air under pressure is filled in the tyre itself through a non retun valve
is fitted to the rim.
TedhKasuld
latis

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 (MSBTESem-VI)
Engineering 4-26 Automobile
obile Suspens
inflatable envclope made of outer cover with aspecial heels
toroidal innerlining.
air-tight card ffabric to retain the air. It d esnot andTyres
Misa pends upon emplay
and part which fit on the circumfcrence of anysealant
the air tight thewheel rim.It consist
iis of beeadcores
The wire.
strandofsteel made
that takes the load and consist
fCarcassis the main structurale ofnubberbounded
ofnumber
contact with rod surface cordsand
surface part that coome in made of synthetic bea
beads.
adis the
Tradi nubber,
an integral part whichaallows high pressure air in
return valve is one way.
Non
and runs coole than the tube tyre
tyre is lighter
Thetubel

Advantages
Advantages
of tubeless tyre

1. Simple assembly

2.improve safety

3. Beter cooling

4. Lesser unsprung weight

Fig.C4.7:Advantages oftubeless
tyre
, Simple assembly: The tubeless tyre are easier to fit and
no danger of puncture during
asembly.
, Tmprore safety: When punchured it deilects slowly in contrast to
tube tyre where air leaks
out fast. This is becanse
soft ining has self-sealing effect. of

Atemporary punctire repair can be made without removing the whel by

stopping the hole with special
a rubber plag
However tubeless tyre cannot be used in spoked wheels since in that case the rim is perforated
.The tubeless tyre should be inspected periodically and
all the förgein objects should be removed
If the objects are allowed to remain in the tubeless tyre they
tends to enlarge the puncture and upair became more
difficult. The chances of sudden tyre punchure leading
to acident are reduced.
4. Better cooling: Heat generated during running is directly
pass from the tyre to the surounding,
5. Lesser unsprung weight: The tubeless tyre
is lighter and runs cooler than the tube tye.
Arretaining- -Tread
Sinear

Carcass

Sleel wire-
bead

Vae
Ne c
cap

RUbber
Rubber sealed
valve

tyre
Fig.4.11.2:Tubeless Tedtaraled
llatie"

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 Automoble Suspension,
Automobile Enginering (MSBTE Som-VI) 4-27 Whel.

Disadvantages
Disadvantages of tubeless
tyre

1. Early replacement

2. Cost

puncture detection
3. Difficutt

Fig.C4.8:Disadvantages of tubeless tyre

1. Early replacement
tightness betuea
repair. Refitting over the rim, the air etween
Duc to frequcnt removal of tyre in case of puncture therim
and
tyre became weak.
2. Cost:

Duc to spocial air sealing the cost is 20 to 30% more.

3. Dilicult puncture detection

Since this tyre retain air even in case of puncture, so it is difficult to realise a puncture in the tyre.

4. Not suitable for spoke wheel.

(4) Comparison of Tubed Tyres with Tubeless Tyres

MSBTE:W-14,S-1

QCompare tubed yres with tube W 14,S1

Tubedtyres ubeless tyres

Suitable for the spoke wheel. Not suitable for spoke wheel.

. Chance of air leakage is more. Chance of air leakage is less.

3. Tube is provided inside the tyre.

Air retaining liner is provided inside
the tyre.
Air sealing quality is poor.
Better air scaling quality.

. Fitting of these tyres is difficult.

These are easier to fit.

6. Strength of these tyres

is more. Strength of these tyres
is less.
(a) Radial Ply Tyre

a Drawneatsketch ofredialply
tyrés and describetheir
MSBTE:S-15
construction
The radial ply tyre have
plies running from
bead to bead across
On the side walls the the crown at right angle
direction ofthese to rotation.
tyre tread there pies is radial and hence
are cord or breakers the name is radial ply
which run around
the circumíerence.
tyre. In between nese d

TedIesaled
Pbiiat
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 (MSBTE_Sem-VI) 4-28 Automobile
neering

OODI
Eho
Tread Thread bracing
Suspens
,Wheelsand Tyres
layers
Radial plies

Inner lining

Radial-
Fabric filler
Cords

Filler Breaker

-
ply tyre
Bead wrap
Bead wires
stip
Tread

Fig. 4.11.3: Radial Fig. 4.11.4:Radial

ply tyre
varies in the range of 18° to 25. The material used
angle een the cord
between for mamfacturing
The will be depend
lateral
ateral stifiness, so accordingly by thenurmber of layer on tyre on
cany and is designed and manufactured.
load to
constructionisis so design to reduces cornering wear and nence increases the tyre life but
The tyre these are moe
expensive at low
speed.
provide greater ability and comfort but does not gives the directional
l plies stability becanse
of breakers
Since they
fimly restrict any ateral stretching of the tyre tread.
are expensive compared to cross ply tyre. But they are more efñcient for fuel economy and, quick
These tyresare stering
response and
puncture resistance.

Ply Tyre Construction (Blas Ply Carcass)

)Cross
1ASBTE: S-15

ss plý fyre and descnbe theirconstrucion

ODra n
cords run in opposite diagonal directions. It is also known as
.In the cross bias tyre construction the altemate layers of
cross bias tyre construction.
moves through the tyre foot print or contact patch.
Bias-ply allows the tyre to squirm as it
provides a cross-cord side wal, which gives rquired
cross-bias cord angle runs from 30 to 40 degrees. This
The
strength to transfer acceleration and braking torque.
Tread

Casing plies Tread

Ply at an
ange
rFUler

Bead wrap

Wall nubber
Bead wires ER
Chafer
Casing plies
Casing plies
Chafer
D)

construction wheels
Cross ply tyre fitted on the front
Fig. 4.11.5: must not be
they
characteristics. But
holding Tecamedgi
This type tyres have better wear and
road
tiea*
only.

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 Automobile Suspension, Wheels
4-29 andTyres
Automobile Engineering (MSBTE Sem-VI)_
otherwise r
on the rear wheels, isethecomering
ply on the front and radial ply tyres
tyres all round, or use cross
Fitted radial
characteristic will be scriously impaired.

()Belted Blas Type

type).
type (Radial ply and belted bias
combination of above two in tyre runnin
Itisa reduction of squirm
results in upto 1006
improvement
compared
stability and
In belted tyres the tread

to bias-ply tyres.
run a number of breaker
belts. Cut section of thie : shown
which
The basic construction
is the bias ply over in
Fig. 4.116.

Stabalizer
belts
Bodyplies at
bias angle

fread

Fig. 4.11.6:Belted-bias type

carcass

4.12 Comparison of Radial and Cross Ply Tyre

ply tyre::
1. Radial ply tyres have following advantages over cross
consumption.
) Lower roling resistance and hysteresis loss which means reduce power
may be upto 100% in some cases. This is on account of two factors
(i) Longer tread life: The extra-life
(a)In radial ply less heat build up.
radial ply iyre does not squim as it meets the Fig. 4.12.2a) and 6) shows the print of two type
The of yem
road which in cross ply there is sideways slip which increase tyre wear.

Cross
Ply

Radial ply

Speed

Fig.4.12.1:Rlling resistance of radial (a) Cross Ply (b) Radial Ply

ply and cross ply tyre
Fig. 4.12.2:Tyre print

ii) In radial ply, sidewall flexibility and treads

region stiffness is more,
the tendency of pattem grooves to sugnuy
close in contact patch area
which is not in cross ply.
Thus the water removal efficiency and hence the brasug
cfficiency on wet road is better
in radial ply.
v) More comfortable ride at high
speeds.
() Smaller slip angle and
higher cormering power
which gives better
self righting torque are higher steering characteristics. The comenng orce nd
for radial ply tyre.

TedAau

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 Automobile Engineering (MSBTE Sem-VI)
4-30
Automobile Suspension,
Wheels and Tyres
During
(vi) turning, a radial ply tyre has ICss tendency
to distort and lift off the
road from one side. Thus
contact of tyTe and hence less tendency to skid while there is better
comcring in radial tyre.

2.
Disadvantages of radial ply over cross ply tyre

1. Heavier stcering at low spccd.

2. Uncomfortable ride at low spced.

3. Instability during comering.

iference between radial ply and cross ply tyres

MSBTE S-17
S19
Diferent radial ply and cross ply.tyres
SS19)
ST.No. Cross ply tyres Radial ply tyres
Stiffness of tyre is more.
Stiffness oftyre is less.
2. Less comfortable due to more stiffness.
Gives comfort for speed 55 km/hr.

3. Tyre grip less on road

Fim frictional grip with road.
The first cost of cross-ply tyres is about 20% Costier than
cross ply tyre.
less than for radial-ply tyres.

5. Steering is easy.
Steering is harder.
. Less tread life. More tread life.

7. Plies are running diagonally opposite from

bead| Plies are running radially. straight from bead to bead.
to bead

8. Cross-ply tyres increase the amount of energy The more flexible

casing of adial-ply compared to
consumed while running, fuel consumption. cross-ply tyes reduces the amount of energy consumed
while running, so that saving in fuel consumption in the
order of 5% is achieved.

413 Tyre Economy: Considerationsin Tread Design

Tread is a pattern design which
is cut into the rubber andit helps to create traction between tyre and road.
ne main consideration in tread the design of treads is grip, noise and wear. These will be discussed in detail in the
following
paragraphs,
a) Grlp:

ne braking grip of a tyre depends upon two factors that are treads material and tread pattern.

d
r dry roads, the completely smooth tyre, no doubt, gives highest braking gip because it provides maximun
of contact with the road,
however, in case of wet road, its grip becomes almost neghgible.
Th
a particular tread pattern is afected mechanically as well as through road friction. For better mechanical
Tor
uct, the tread must provide suitable sharp edges that will engage with the road.
While for
a good
tood frictional contact, it is very importan that tyTe must provide drainage of the water on the
road,
aerwise
byre will aquaplane, that is float on the water film and loose contact with the ground.

Techalelgi
Pllcatioas

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 Automobile Suspension, Wheels a
Automobile Engineering (MSBTE Sem-VI) 4-31 andTyres
requirements. Sufficiently wide grooves at the middle.
.The various tread designs aim at saisfying these two basic deofthe
tread serve to drain the road watcr.
comparatively narrower grooves provide
It has been found through experimentation that more number of bete
better
drainage as compared to small number of very wide grooves

b) Nolse:

A part from the 'squeal' peculiar tyTe noise which depends upon the nature of the rubber oompound used for thebyte
ty
treads.

Various types of vibrations caused by the roughness of the road surface andor by the distortion of the tyre carasa
so
produce noise.

However, besides these, the type of tread pattern also contributes to tyre noise. It is seen that this source of noise
i
eliminated by providing intentional iregularities in the tread pattem by varying the size or shape of the tread biock
cks
slightly

cWear :
For less wear, the tyre tread must be such that the individual elements undergo miimum distortion during running

4:13.1 Factors Affecting Tyre Life:

MSBTE:S-15. W-16.S-19
Siovanoos tactosatointyelite
Q pan anyiourfactor affechngHTE
te
The life of tyre is greatly reduced by under inflection, rapid stop, fast acceleration, road surface, misalignment and
unbalance condition.

Tyres wear quickly on sand and gravel roads whereas the tyre life is promoted to its
maximum value by the concrete
and asphalt roads. In addition to normal wear caused by evenly and smoothly worm
tread.
The tyre life can be greatly influenced by the factors as explain below.

Factors affecting
tyre ife

1. Atmospheric condition

2. The road surface condition

3. The Route

4. Type of work.

5. Style of driving

6. Inflation Pressures
and Load

7.Correct alignment of
wheel

8.Proper maintenance

Fig.C4.9: Factors affecting tyre

life

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 (MSBTE_Sem-VI)
4-32
Engineenng Autormobile
Automobile Suspenslon,
heels andTyres
condition
Atmospheric
1. generateu docs not affcct by climate and seasonal condition but
The
heal
high
neraturc rubber gels softened result
tempcrature nubbe in decreases
it affects by the way
of heat dissipated
surounding.
ng. At the abrasive resistance causes
more thread
to
WCar.
ondition water acts as a lubricant to rubber which reduces
scason tyre wear but chances of puncture
In rainy' bber cut more
casily in wet condition as it depend on nature it is
unavoidable.
inereasesas
surface condition
The road
greatly abrasive than tarred road as it is made from varying size of stone.
Concra roads are Gravel road and extremely

smooth that
cffect wear.

The Route
3 roads tyre and tyrelife reduces while winding road on a hillya
areas, tyres wear much faster when to brakc,
On traight
suddenly and accelerate tinuously, even when speeds are relatively low.
changedirection

Type of work
4
ime :available
The time for cooling tyre is less on long and high sped runing. So continuous runing reduces tyre life and
unavoidable.
itis
driving
5 Style of
The tyre life decreases
with the increasc of car speed.
or turming greatly reduce the tyre life while maximum tyre life and economy
starts, quick stop, high speed running
.Fast
is promoted by conservative driving
habits but this can be avoidable.

Infiation Pressures and Load

in under inflated. The frequency of side wall deflection
The sidewall of tyre is deflected due to overload as same as
increases with increases in speed of vehicle result in more heat
generation causes more defilection. So tyre will damage

or fails if it allowed for longer period. So tyre failure depends

on amount of load, speed and distance traveled.
with the ground and the relationship betveen
The inflation pressure also influences on the tread which makes contact
uneven (and therefore, accelerated) tyre wear because the tread not
the tyre and the rim. Both these factors can increase

makes contact with the surface of the road across its full arca.
1. Correct alignment of wheel
treads is
the inner side of the tyre
and much camber the outer ribs will get warnt out. The wear on
EXCessIVe too due to
outer area of the treads is caused
y the negative camber. The excessive wear on both the inner and
excessive skidding
on turn.
excesive wear if ine
Du
scrubbing action on the road surface resulting in
toein l0e-out will affect the tyre life the
loe in or toe
out is not corect.

Unung /demounting of tyre causes bead damage exposing the bead wire.
.Propermaintenance
Wheel
alignment due to bad bump
t and balancing suspension settings which may change
413.2
Types of Tyre
Wear: NMSBTESW15:S-17|W:18

W-15)
Stateany
ght probable.causes s
of tyre wear and gve its remedies S-17, W-18)

OUr0pableprohsRA causes of tyre wear

De with
and give its remedies i172
ech.the effect of (i) Under inflation (2) Over Inaud TechKnauledgë
ICaleas
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 Automobile Suspension, Wheels and Tvrae
Automobile Engineering (MSBTE Sem-VI) 4-33
Types of tyre wear

(a) Under inflation

(6) Over inflation

(c) Poor alignment

()Wheel imbalance

(e) Fast turning on curve

( Incorrect toe

Fig. C4.10:Types of tyre wear

(a) Under inflation: Both edges wom, squealing on curves. Under-inflection is the most usual cause of reduce tyre
life
This causes the side of the tyres of its walls bend sharply as the wheel revolve. The cords eventually brake
and the tye
blows out with the further revolving of the wheel. Tyre wear at the centrally excessively
and less on outer edges.
Itis detrimental to life of tyre. It causes excessive flexing in irrepairable damage to the tyre carcass
or visible cracks on.
side wall, loose card inside casing

2) More tread wear on the side

3) Chances of rim bruises increases due
to decrease resistance of the tyre to deflection.

Crack
side wall

Fig.4.13.1:Underinflation
(b) Overinflation:

1. Rapid tyre wear at centre

only.
2. Abnormal stresses
and strain in treat
area causes separation
3. Decreases resistance of ply and tread cracking.
to skidding because
of reduction in contact
4. Poor alignment surface of tyre trade with roaa.
: One side wear, saw
toothed wear pattem.
5. Wheel imbalance:
Treads worn unevenly
6 with bold spots,
Fast tuming on cups or scallops.
curve: Front tyre
wear only.
7 Incorecttoe:
Feathered edge.

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 Engineering(MSBT Sem-VI 34
mobile Automobile Suspension,
Wheels and Tyres

Tread wear and Tread wear and

crack at centre crack at cetre

Fig. 4.13.2: Over Inflation

4.13.3 Tyre Rotation:

automobile from one position to another, to ensure
. Tyre rotation is
the practice of moving the wheels and tyres of an
weight on the front and rear
wear is 'desirable to extend the useful life of a set of tyres. The
even tyre wear. Even tyre
axles differs which causes
uneven wear.
guidelines as shown in the
wheel to another wheel as per manufacturer 's
Rotation means to rotate tyres from one
.Tyre
igure

With spare wheel

Without spare wheel

For heavy vehicle

with spare wheel

Rotation
Fig. 4.13.3: Tyre
Justification after
intervals. Generally
after fixed
be rotated depth, if
In order that recommended that tyres tyres tread
the tyres wear uniformiy. It is
allyTes are : As wear reduces a
Every 8000 wearing uniformly maintaining the
comering and
kilometers of operation. The advantages of tyres
input equally
allthetyres respond to the driver's
handlin
wear at the
ne
characteristics.
rae, all of them would
increase tyre life tyre
position should be
changed at cach
service.

Tedhlenledys
atises

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 wheels and
Automobile SuspenSIon,

Engineering (MSBTE Sem-VI) 4-35

Automobile
(Designation of Tyre)
Specification of Tyre: MSBTE
S13
4.14

diflerent iype of yre wear

913
7 Explain diameter. They aremarked
a.How tyres are specified sectional width and m
nominal size oftheir
by the
tyres are specified and designated
The
1 Rim diameter
as P205/75 inches
in

P-Tyre type Aspect ratio

P-Passanger Sectional height
C-Commercial Sectional with
Constructional type
Sectional with typpe
P-Tyre
P-Passanger
C-Commercial

habit and vehicle

factor like tyre load. Intlation pressure, driving
detecrmined by
life and performance are
Tyre
maintenance

Example
ratio of 75 and
passenger car tyre with sectional width 205 mm having aspect
P20S/75R15 as specified above indicate

adial ply rating of 15 inch wheel diameter.

4.15 Wheel Alignment

MSBTE:S-14, S-15, WVA8

QDefine Wheel Alignment

Why wheel alignment is necessary

State the necessity of wheel aligoment. -17

Describe is procedure
State wheel balancing and wheel alignment
Definition The wheel alignnent meuns.correct adjustnment of the front twheels with respect pip h
and controlling steering movement to the wheel giung the directional stabilih tove
stecring and rediuces the wear tó amininum
enter and
The directional stability of vehicle means the condition that it possess if it can rin straight down on 1
leaves the circular path easily and resist road shock.

Purpose (Necessity) of Wheel Alignment

above
the
DuE to Tunning of vehicle over a period
of time on various road conditions leads to change in the seting
mentioned parameters.
vehicle8
In wheel alignment all these
parameters are set to their design values. Otherwise direu
nampered. Uneven tyre wear,
damage to various links of steering system may resut
in-toe-ou
loe
gnent
explained earlier
depends upon wheel
geometry ie. caster, camber, kingpin inclinao
in wheel geometry.
Tectlarada
bieotlee

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 Engineering (MSBTE Sem-VI) 4-36
omobile
Automobile Suspension,
Wheels and Tyres
allowing factors
affecis the whccl alignment:
Thei pertaining to wheel:
Factors
Balance of wheel (6) Inflation of tyre
(a)
Steening geometry
(c)
geometry
Steering
2
Camber 6) Caster
(a)
inclination (d) Toe-in and Toe-out
C)Kingpin
Steering linkage.
3.
Suspension system.
4.

415.1
Procedure (Checking9) of Wheel Alignment:

of wheel alignment, is to inspect the king pin inclination, camber and caster anges and toe-in.
De fint sep
Eor igid axle suspension system camber angle and king pin indention is fixed and caster angle can be adjusted by caster
plate.

Whereas for
vehicles having independent suspension system, the above mention angles are adjusted by a shim between

the lower and

upper arm brackets or by eccentric clamping bolts of the arm
used. This gauge
For inspection of camber, caster and king pin inclination, a specific type of standard ganges are

consists of two part-

Level and angle gauge,

)Tuntable.
Co. gives very acurate and precious reading used to measure toe-
One of them gauge is optical gauge of Dunlop Tyre
used in workshops.
in. Telescopic gauge is commonly

Rod-
Poinfer

Scale Pipe

Pipe adjusting srew

Fig. 4.15.1: Toe-in gauge

on
width. A vetical rod is mounted
This
of which one can be slide on another to adjust the
consists of two pipes,
rod s
requiremeat of wheel. The vertical
can be adjusted at any position on the pipe according to
andwith adjustable
PTOvided
pointer which moves up and down on rod.
To inspect n the pointers of the gauge touches with the front wheels,
measure and note the reading
on ine pipe.

the reading and

Similarly,
when the portion of the front wheels and note
of the gauge touches with the rear
pOinters
calculate
difference between the two readings gives the value of toe-in. edaeo
Dlatisos

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 Automobile Suspension,
Autormobile Enginaerlng (MSBTE Sem-VI) 4-37 Wheels
andTyres
4.16 Wheel
Balancingg
MSBTE W-14,S-14 S-15,W-17.
W-18,
necessary ?
S-19
Q. Why wheol balancing ls

.Explain what do you mean by whéel balanclng

QState the necessity of wheel balanicng.

Q. State wheel balancing and wheel alignment. Describe its procedure;
Wheol Balancing:

Definition: It is a process that ensures wheelspins triesyas tiev ar jittedkorn dvehice tn

not spinning properly then there are probtenis iugventire uear nhicte pulinon
ie a
bouncing ofä vehiele, uhel shm ete whicpejace do hen ihts don o
The method, of addition of small weight to the wheel rim to avoid wheel wobble and vibration
and easy to steer
for
for A:
it should be statically and dynamically balance. tis
Wheel balancing is the process of correcting the lateral run, radial run out
and addition of weight to
avoid uneven
u
distribution of the weight about the rotational axis of wheel

Purpose of Wheel Balancing (Necessity )

During the running of vehicle the tyres gets worn out and whecl rim gets bend or damaged.
There may be lateral nun out of wheels, Radial run out may be created due to tyre or rim out of conditions.
This leads to
uneven distribution of weight around axis of rolation
of whecl assembly. Because of this there is an unbalance
created
in the wheel assembly.

If this unbalance is not removed, then this may lead

to wobbling of front wheels, viþrations, tyre
wear, and may
adversely affect steering system assembly
parts. This can be avoided by balancing.
The balancing of a tyres whecl is most essential
to avoid the front wheel wobble. Which affects steering and increase
tyre wear rate. The factors affecting the
wheel balance are as follows
1. Lateral run out of the wheel.

2 Radial run out or run of round the

wheel, caused by tyre or rim
out
3. Uneven distribution of the weight
around the axis of rotation.
Therefore it must be necessary to
inspect the wheel centering, before
checking the wheel for balancing lateral n ou
which result of a wraped rim from
bumps and can be corrected by
arbor press.
The tyre must be removed to straighten
the wheel rim. Tum the wheel about
its axis and check the wheel insioe
retaining the tyre bead and the
rim well from ran out in excess i
of 1.5 mm.
General Procedure of Wheel Balancing:

Fll tyre with recommended tyre

pressure, check for tyre / wheel
damage don't use damaged rim for balancing
1. Mount wheel on balancing
Machine and lock it. Remove
2. old balance weights.
Set balance for size of
tyre and start the machine.
3. Read values of imbalance
on right and
left side of wheel on display.
4. Put respective weights
on both sides on marks.

ati"
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 Automobile Engneeing (MSBTE_Sem-VI) 4-38
Automobile Suspension,
Wheels and Tyres
Startbalancer again and check that reading is zero on both sides then the wheel
is balanced.
both sides is not zcro then repeat the procedure.
6 Ifr cnding on
Methods of wheel
Balancing:

416.1 Static Balance of Front Wheels:

MSBTES-183
the procedure of wheel balancing
oState
Thisncan be done with the
whecls installed on the vehicle
by using electronic balancer.
S-18
This gives remarkable advantage
balancing the wheellalong with theotherrotating masses. The procedure
of is as follows:

Lit
Ange
the front whels on hydraulic jack such that the whel is frely rotated.
spinner, which carries
the the balancer equipment, with its pulley in
) touch with the tyre tread, the wheel
should
bein straight ahead position.
( Move the balancer into position to point to strobe light at the w el.
fa Position the pickup magnet in contact with a clean tlat surface on the front suspension as closed
to the wheel as
possible.

(e) Apply the reference mark on the wheel cap on the tyre, consisting of a radial line. Use chalk or a length of tape.
(0 Shift the balancer switch to position 1 and wait some minutes to allow the warm up
of tubes if the pick up magnet is in
proper contact, the strobe light wil fash when the top of the tyre is tapped.

(c) Start the wheel by hand, snap on the switch of the spinrer motor and hold the spinner pulley against
the tyre tread to
Tevup' the wheel.

While spining, the following conditions are experienced

1. The flashing of the strobe light will make the reference mark on the wheel appear to fixed
be in the same position.
2. Watch the meter of electronic balancer. The needle will move on from zero position. When it reaches its highest
reading and starts moving back, pull the spinner away.

3. Inertia causes the wheel to keep turming, and the needle will rise
again. When meter needle shows its higher
Teading, note the position of the reference mark. Consider the reference mark as the hour hand of a clock. The
"time" the reference mark indicates the position
to remember.
(6) Repeat the above inspection
procedure and note maximum needle reading on meter dial
fhe needle still moves beyond green
area of meter dial, proceed as follows:
L Stop the wheel.

2 Move the wheel on same

reference mark position or time recorded at g.
S.Change or shiíft the balánce weight applied,
to wheel.
he check as directed previously.
TDeler needle
remains
If the wheel is still out of balance, proceed with the balance procedure, till the
in the green area of dial meter.
18.2 Dynamlc
Balance of Front Wheels
n the wheel
out approximately one
6) Positionthepickup half of their steering angle.
magt in contact with the
0 Spanthe
wheel
nagnet external front end of the brake housing flange at the wheel rotation axis.
and record the highest
balancing meter reading as well as coresponding position of reference mark as per static
procedure.

TechKaowledgi
7Plcatioos

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Automobile Engineering (MSBTE Sem-VI) 4-39 AutomobileSuspensi Nheels
andTyres
() If the meter moves out of the green area on the dial mcter, the wheel is out of balance, in this case follow heprocedure
as:
. Move the wheel by hand to the same reference mark position as noted at 3.

2. Divide the total indicated weight in half and apply.

One halfat the inside front end of the wheel,in line with horizontal wheel axis.

The other half at the outside rear end of the wheel, in opposite position to the first half.

(c)Check the dynamic balance of the wheel as done for the static balances.
(0 still out of balance, stop the wheel and bring the reference mark in corespondcnce with the posidion
or üme
recorded in 'F.

Repeat the inspection as previously directed If wheel is out of balancing, repeat the above procedure till he
meter
needle remains in the green area of the dial meter..

Review Questions

Q.1 Why suspension is necessary for automobile ?

02 Give classification of suspension system with application.

Q3 Slate the functions of suspension system.

Q4 Sketch and explain leaf spring for rigid axle suspension.

Q.5 Sketch and explain Mc-Pherson independent suspension system. State it application.

Q.6, State advantages of front axle independent suspension system.

Q.7 Explain working of air suspension system with neat sketch.

Q8 Slate the necessity of wheel balancing and wheel alignment.

Q.9 Explain working of telescopic shock absorber with sketch.

Q.10 State the functions of wheel and tyre.

Q.11 Enlist type of wheel and explain disc

wheel with sketch.
Q.12 How tyre and wheels are specified ?

Q.13 State the advantages and disadvantages of

cost alloy wheel.
Q.14 Enlist the type of rims. Explain construction
of any one with sketch.
Q.15 Enlist the properties of good tyre.

Q.16 Give the classification of tyre.

Q.17 Draw a neat sketch of tube

tyre and label it.
Q.18 Diferentiate tube and tubeless
tyre.
a.19 Compare radial ply and cross ply tyre.
Q.20 State the various factors
affecting tyre life.
Q.21 Define wheel alignment
and wheel balancing. Explain
the procedure for wheelalignment.

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 Tablo of Contenta
Automobllo Enginooring(MSBTE Som-VI)

5.3.4 Mothoda ot Ratlng of Battory

UNITV (Charactorlsto of battery)
.5-12

Capacity of Battory OR Spocificatlon of Batterym6-14

Chepter 6 Automoble Electrical and Elactronica 5.3.6
5-1 to 5-50 Typoa of Battory Tost
.. B-14
Systom 6.3.0
&-16,
6.3.7 Sallont loaturos of Maintonanca foe battery..m
Sylabus
Eloctrical-Eloctronlc Systom: Basio 4 Startng Systom..
6.1 ntroductlon to
Electrical-Eloctronlos Principlas (Cumont, Voltago, 54.1 Roquiremonta of tho Starting Syotem.
Eloctromngnetlsm,
Rosistance, Eloctricty. Magnotisin, Compononts and Functions of Automoblo
Eloctronics 5.4.2
nducton, Rectficaton, elc) Basic Eloctricnl- G-17
in automobiles' with tholr conventional Starting Systom..
Conconents usod
symbols. 5.4.3 Layout and Worklng of Starting Syatem.

Function and Roqulrements of Battery, Typos

of
64.4 Bendlx Orivo. 6.18
5.2 Battor: Construction onu
Battery, Princlple of Lead Acld Dattery, 19
5.5 Charging systom.
Oporation of Lead Acid Battery, Significance f Battory
Battory Open Volt and Speclf 5.5.1 Functlon and Roqulremonts of Charglng systom .5-19
Rathg and Battery Copacity,
Gravity Test, Salient Features of Malntenance Froe
Battery. .5-20
5.5.2 Altemator

6.3 Starting System: Function and Requirement of Startng 5.5.2.1 Working Princlplo .. .5-20
System, Components of Starting System, Construction and
5.5.2.2 Altormator Compononts and tholr Function
.
Working of Standard Bendix Drive..
5.5.2.3 Construction 5-21
6.4 Charging Systam: Function and Requirement of Charqing
Charging of Battery by Altonator 5-22
System, Components of Charging System, Construction end 5.5.3
Working of Altemator.
5.6 Ignlion Systom.
of Ignltiorm
5.5 Jpnidon System: Function and Requlremernt 5.6.1 Function and Roquiroment of lgnitlon Systom. 5-23
Working
System, Types of lgnltion System, Construction and
lgnitlor 5.6.2 Typos of Igniton Systoms. 23
Battery lgnition, Magneto lgnition and Electronic
of
System with advantages, disadvantages, applicatons. 5.6.3 Difference betwoen Battery lgnltion System
. 5-27
of Lighting and Magnoto lgniton Systom
5.6 LIghting Systom: Function and Requirements
Systems, Typos of Ughts, Necessity and Importance of 5.7 Lightng Systom. 5-29
Cable Calor Codes, Wiring Hamess.
5.7.1 Introductlon 5-29

5.7 Miscellaneous: A Briet Revvew of Ditferent types of Gaugos,

5.7.2 Function of Lighting Systom nsesLATEA**** 5-30
Windscreon wiper, Function and Locatlon of Major Sonsors

and Actuators used in Automoblle Electronics. 5.7.3 Roqulremont of Ughting Systom. 5-30

51 Introduction to Basic Electrical and Electronlc. .51 5.7.4 Typos of Ughts. 0

Vehicde..5-2 5.7.5 Importanco of Cablo Color Codes Usod lor Wiring
62 Eloctrical and Electronic Components of

5-6
the Lighting Systom ... 535
5.3 Battery. sneessoredressasesdso ceeano*aapaoea*d***4***e*segoeene********e*

5.7.6 Wining Hamos9

Functions and Requlrements of Battery

5.8 Different Typas of Gaugos..

5.32 Lead-Acld Baltery. ******agsnssosa*e****s*************************
,5-7 .5-30

5.3.3 5.8.1 Gaugos

Working (Operation) of Battery.
ea***a***7***e**************** 5-10 **44*********

Wind Screen Wiper.

533.1 Factors Affocting Battery Life. .5.11 5.8.2 ..5-43
5.8.3 Automotive Sensors
and Actuator.
* 44
Trhlanvledgi
atlo
 Automobile Electrical
5 and Electronics System
Unit-V
Syllabus:
5.1 Introduction to Electrical-Electronic
System: Basic Electrical-Electronics Principles
(Curent, voge,
Resistance, Electricity, Magnetism,
Electromagnetism, Induction, Rectification,
etc) Basic Electricak Electronics
Components used in automobiles
with their conventional symbols.

52 Batteny: Function and Requirements

of Battery, Types of Battery, Principle of Lead Acid Battery, Construction
and Operation of Lead Acid Battery,
Significance of Battery Rating and Battery Capacity, Battery Open Voft
and Specific Gravity Test, Salient
Features of Maintenance Free Battery.
5.3 Starting System: Function and Requirement
of Starting System, Components of Starting System,
Construction and Working of Standard
Bendix Drive.

54 Charging System: Function and Requirement

of Charging System, Components of Charging System,
Construction and Working of Altemator.

55 lgnition System: Function and Requirement of Ignition System, Types of lgnition

System, Construction and
Working of Battery Ignition, Magneto lgnitilon and Electronic Ignition
System with advantages, disadvantages,
applications.

5.6 Lighting System: Function and Requirements of Lighting Systems, Types of Lights, Necessity
and Importance
of Cable Color Codes, Wiring Harmess.

5.7 Miscellaneous: A Brief Review of Different types of Gauges, Windscreen wiper, Function and Location of
Major Sensors and Actuators used in Automobile Electronics.

5.1 Introduction to Basic Electrical and Electronic

Electic curent is used for a number of purposes in the automobile, electric curent flows through different system to
fulfill the different objects of cranking the engine. For staring, for production of spark to burn the air fuel mixture in
SL engine, charging of batery, lighting the lamp, blowing the horm, electrical fuel pump, wind shield and many others
unit of automobile.
Electricity is the movement of electrons. Electrons create charge, which we can harméss to do work. They all operate
using the same basic power source
or more specifically, the charge they create:
The three basic principles explained using electrons,
points.
o Voltage is the difference in charge between two
flowing
o Current is the rate at which charge is
to charge (Current). Resistance is measured in ohms (Q). The
Resistance is a material's tendency resist
the
tlow of
o
the resistance.
higher the temperature, the higher
EICcincity is flowing through a conductor while a magnetic field is
Electricity and magnetism are very closely related.
or a it create electron flow inside of it, which can be
created around it. a magnet move near conductor in coil,
a
If
develop an electricity.

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 Automobile Electnicaland Electronics
5-2 onicsSystem
Sue
Automobile Engineering (MSBTE _Sem-VI)_
work or to generat
clectrical systems to do mechanical theelectricity
throughout automotive
This principal is used
that rnuns the vehicle. a conductor as a result c
an clectromotive force (em)
in
production of f achanging
Elcctromagnctic induction is the
magnctic ficld about the conductor. electromotive force across an electrical
is the production of an 1ga
Electromagnetic or magnetic Inductfon discovery of induction in
generally credited with the and James
ficld. Michael Faraday is
changing magnetic
law of induction.
Maxwell mathematically described it as Faraday's
Clerk Magnetic Lines
of Force

AAANAAL

---*-**
=-=-*=--*

Fig. 5.1.1

Rectification:
(DC).
altemating curent (AC) into direct curreat
Rectification is a process that converis
OR

altermating curent (AC), which

peniodically reverses direction, to direct
electrical device that converts
A rectifier is an rectification, since it "straightens"
the
direction. The process is known as
current (DC), which flows in only one
direction of current.
Vehicle
5.2 Electrical and Electronic Components of

components of Vehicle
Following are the Electrical and Electronic

Resistors 2. Capacitor

Semiconductor 4. Diodes
3.
Zener Diodes 6. Transistors
5.

Rclay 8. Solenoids
7.

Fuses 10. Starter

9.

Resistors
nerg)
opposes curent flow in a circuit. It is a two-terminal element, dissipates is
A Resistor is a passive element that
in the fom of heat. The resistor
will damage due to the overflow of electric
curent through it. Resistance
s t
resistance.
in units of ohms and
are not
Is function is to limit current 1low and and thereby voltage in circuits where full current flow and voiu
needed or desired.
etlaculndgi
ti

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 Automobile Engineering (MSBTE Sem-V) Automobile Electrical and Electronics
Syste
5-3
Provide fixed voltage drops.

The resistors
used in clectronic circuits are manufactured from small carbon rods, and the size of the re
determines its resistance.

Cutbon resistors havc

a negative temperature cocfficient (NTC) and this must be considered for some applications.
more stable tecmperature propertics and are constructed by depositing a layer of carbon onto n
Thin film resistors have
insulated former such as glass.

Resistor Variable Resistor

(Aheostst)

Variable Resistor Variable Resistor

(Potentiometer) (Preset)

Capacitor
2
store an electric charge. In its simple form it consists of two
plates separated by an
The function of capacitor is to
charge but
insulating material. The capacitor constitutes of
di-electrical materials having property to hold electrical
In automobile it is used for reducing
arcing acrOss
cannot flow the free electrons through these like air or paper.
contacts breaker point.
electrons are accumulated to one side start shifting to
the dielectric substance is connected to the voltage the
Where
another side which is called charging of capacitor.
difference of the capacitor. As
The charging continue till the applicd voltage across the source became equal to potential
circuit.
soon as circuit is off the suspended electrons continue to pass through the

capacitor

Variable
capacitor

The use of capacitor inIgnition system is to protect the piting of circuit breaker
point. If the area of the plates is A, the
distance between two plate is L, and then value of capacitance is C= AL.

3. Semiconductor:

These cannot provide a current flow when purë but when another small amount of
material is added to a semiconductor,

then it provide movement of clectron.

P-type.
Depending upon the type of impurity (material) added they are called as N-type or

material are poduced by doping sillcon or germanium with a element having five electron in
Naype semiconductor

beir outemost orbit E.g. Phosphorus, antimony or bismuth.

St
bimilarty P type semiconducior
is obtained by doping gérmanium or silicon in the element having three electron
Boron, aluminium in outermost orbit.

TechKanuledgi
Puslcatloas

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 Automobile Electrical and Electronics System
EAutomobile Engineering (MSBTE Sem-V)
54
4. Diodes
A Diode is an clectronic cathode. It allows clectronCurrent flow
compon with two terminals that are anode and from
IC to anoxde but it blocks another dircction means allowing current to flow in one direction only.
direction.
wil have low resistance in one direction and high resistance in another
Oe
The diodes are formed by combining P-1ype and N-type semiconductor.
Diode

Dioda

Battery

Battery

a) Forward bias (b) Reverse bias

Fig.5.2.1:Diodes
5. Zener diodes:

These are used for low voltage circuits, wave rectification circuits and so forth.
6. Transistors:
It is a semiconductor device which can be used as an electronic solid state switch or a current amplifier. Transistor are
made in three soction N and P type material. It may be PNP transistor or NPN transistor.
Central section is calied base and one end called emitter and other is called collector. Base control the current flow

NPN PNP Photo

Transistor Transistor Transistor
NPN type

ow Caurent
Base Bas
cument
CuTent

Emitar Base Collector Emiter Base Coletor

(a) NPN Transistor (6) PNP Transistor

Fig. 5.2.2: Transistors

oulsin
Transformer: It is used to produce AC power supply, energy is transferred in between primary and secou
the form of mutual inductance.

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 Electronics System
Automobile Engineering (MSBTE Sem-VI) 5-5 Automobile Electrical and

Transformer
circuit symbol

current circuit.
7. Relay: A Relay is an clectric switch that allows a small amount of curent to control a high
chanica
current flow into
8. Solenolds : Solenoids arc clectromagnetic switches with a movable core that converts
movement.
current and it is used to provue
9. Fuses: Fuses providc protection from high current. The fuse will fow suficient
over current protection.

Fuse circuit symbol

10. Starter :
when the igniton swi
Located on the back of the engine or the front of the transmission, the starter cranks the engine

is turned on.

Diodes

Diode

Zener Diode

Tunnel Diode

2. Capacitors capacitor

Variable
capacitor

3. Resistors
Resistor Variable Resistor
(Rheostst)

Variable Resistor Variable Resistor

(Potentiometer) (Preset)

4. Battery Circuit:

Fuse Circuit

Fuse circuit symbol

Tec Kauledgi
Y Pblltatiuns

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 utomobile EIectncal an0 Eiectronics
nicsSystem
Svs
Automobile Engineering (MSBTE Sem-V) 5-6

6. Transfomer

Transformer
circuit symbol

Transistors

Photo
NPN PNP
Transistor Transistor
Transistor

5.3 Battery
5.3.1 Functions and Requirements of Battery:
MSBTE W:14S16 S-17

(W-14)

QExplain the functionsof battery (S-16)

construction and working with neat.sketCI
Sate function of battery Explain its construction
the function of battery in
of lead acid tbattery.xplain is
an automobile: List the. main components
(S17
State neat sketch
ith
battery, engine cannot be started with
the
is main part of the electrical system in an automobile. Without
The battery the
starting motor.
starting motor, ignition system, head
battery supplies curent to various part of the automobile vehicle such as for
The
other accessories.
and tail light, brake light, to wiper and
construction since they have to withstand several vibration.
Vehicle batteries should have robust
different automobile
charging rate as well as heavy discharge convent required for
The battery must have the high
service.
engine.
starter motor and low current to ignition system to start and operate the
(1) Battery supply high current to

(2) It supplies cureat to

accessories which operate electrically.

and control the voltage regulation of electrical system

(3) It stores the electrical energy
the lights, instrument and other electrical accessories.
4) It must provide the power to operate

Principle
chemical eaergy
Generally a battery works on the principle of Elctro-hemical Reactions in which the conversion of
electical energy in bateries. I consisting of negative terminal is anods and positive terminal is the cathode underges
into
two or morc ions from the electrolyte combine with the anode to form a compound
an oxidation reaction: during discharge
Simultaneously, the cathode, undergoes a eduction reaction and deliver an electical
and release one or more electrons.
energy to an external devicc.

Kasledgi
Tech
PBIcstisus

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 Electronics System
Automobile Engineering (MSBTE Sem-VI) Automobile Electrical and
5-7
Types of Battery

. The typc of batteries are

1) Lcad-acid battery

2) Alkaline battery

i) Nickel iron type i) Nickel cadmium type

3) Zinc-air battery

4) ZEBRA Battery (Molten Salt Battery)

5)
Sodium-Sulphur Battery

6SwingCel
7) Lithium ion battery.

5.3.2 Lead-Acid Battery:

S-18
MSETE2S14, W-14, S-16, W-17

a State constrüction of lead acid Battery.

14
(W-14)
xplain is construction WIth neats
oListhe main components otlead acid battery S1,$1
working of lead acid battery wth neatsketch
O. Explain the construction and
Describe with neat sketch construction and working of lead
acid battéry W-17
device.
automobile vehicle. It is an electro-chemical
lead acid battery is widely used in
The current force through the battery
can produce current as a result of chemical reaction. A reverse
and
It has a voltage
and restore the battery material.
which cause chemical reaction
battery is explain below:
construction with component of lead acid
The
(A) Battery Construction

component:
It consist offollowing
Components of
battery

(a) Container

Grids and platess

(6)
(c) Separators

(d) Cell cover

Electrolyte
(e)
(0 Cell connectors

(g) Taper terminal

(h) Sealing compound

Fig. C5.1:Componenets of Battery

echanaledyi
Y lations

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 Automobile
Engineering (MSBTE
Sem-VI)_ Automobile Electrical and Electronics Svste
AUTOTTTO
5-8 Senm
(a) Container

it is constructed
in single
piccc and made of acid resistant of hard rubber or plastic or bituminous composition. Nowa
04y Polypropylene is
a
uscd, which is strong translucent and light in weigu
It is divided by partitions
into compartmcnts for individual cell.
bs arc there at the
bottom of each compartment. The battery plates rest on these nos

pace between the ribs is provided to

collect sediments. This minimizes the danger ot short circuit due to sediment.
b) Grids and plates

ne attery plates
are made of a lead alloy containing six to cight percent antimon, wnich makes them resistant to
electrochemical corrosion
and gives them strength and nigidity.

ne plates are in the form of grids.

Number of plates of positive and negative types and separators are there in a cell.
On the plate grids, lead oxide paste is applied.
Then plates are assembled into a balitery.
The cells are filled with electrolyte
and given an initial charge.
This changes the lead oxide paste on
the negative plate io sponge lead which is grey in colour and changes the ead
oxide paste on the positive plate to lead peroxide
which is brown in colour.
The plates are properly spaced and welded
to a lead antimony plate strap. This form a plate group.
Each cell is composed of Negative and Positive plate
group and separator.

The Negative and Positive plates are aranged altermatively.

(c) Separators

Separators are placed between the negative and positive plates. This
prevents the positive and negative plates from
direct contact with each other, resulting intermal short circuit.

Also they may be porous to permit electrolyte to circulate between

the plates.
The separator is made of wood, spun glass, porous rubber sheet, glass fibre
or resin impregnated fibre.
Some batteries have separators made of polyvinyl chloride or polyethylene
saturated cellulose.
Separators have ribs on the side facing the positive plate to provide
greater electrolyte volume next to the positive and
this improves efficiency by increasing electrolyte circulation.

(d) Cell cover

Each cell is sealed by a cover of hard rubber through which the positive
and negative terminals are projected.
Adjacent negative and positive terminal are connected by cell connector strap.

Its cover has an opening for filling the electrolyte and a filler cap is provided
on this opening with an air vent to escup
the gases.

The edges of cell cover is sealed with asphaltic sealing compound.

Kauledge
Tech

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 Automobile Engineering (MSBTE _Sem-VI) Electronics 5yste
5-9 Automobile Electrical and
er cap
(e)Electrolyte Positive teminal
Coil connector

Sealng
compound 7O
Cell coverss

Negatve
terminal

Container

-Negative pkate

-Separator

Positive plate
Element rest
Sediment space

Fig. 5.3.1(a) :Constructional details of battery

The sponge lead and lead peroxide

which fill the respective plate.

Electrolyte is a chemically pure sulphuric acid diluted with

distilled water.

It consists of 40% sulphuri acid and 60% distilled water.

1.25 to
with dry charged plate ranges from
The specific gravity of the electrolyte poured into a new battery
plate.
gm/cm. The level of electrolyte must be 10 to 15 mm above the top of the
1.28
battery is given an initial charge then it is ready for
operation.
When the electrolyte has been added and the
Vent cap

One-piecs-
cover

Over-partition connector
Cell partion
Teminal post

-case

Mounting
case
Cell connector
Sediment space- -Element rest
Fig. 5.3.1(b): Partly cut away and disassembled 12-volt battery

Techaouledë
hcatons

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Automobite Engineering (MSBTE Sem-VI)_ 5-10 =
Automobile Electrical and Electronics:
System

(0 Cell connectors
cover.
adjacent cell just above tne cell
LOr straps conncct the negati ve and positive terminal post of the

Each cell of a lead acid battery produce 2 vols

required for starting without overheating
LICOTS must be heavy enough to carry high current
(gTaperterminal
dimension. So that all positive and negative cable clamn
DxLCTy teminals are of special design made tapered to specific
will be fit

ne positive terminals are slightly larger in diameter at top than negative terminal.
(h) Sealing compound

having resistance to iow at hgh temperature

hey are blends of specially processed bituminous substance
and

resistance to crack at low temiperature.

5.33 Working (Operation) of Battery:

MASBTE: S-09.W-09

S-09, Was)
plan the working of batery, used in automobiles

charging or discharging
The working of the battery can be understood by knowing the changes taking place during the
of the battery.

Chemlcal reaction during charging and discharging

A fully charged lead-acid battery consists of lead peroxzide (PbO) as the positive plates, spongy lead (P) as te
negative plates and diluted sulphuic acid (HLS0,) and (H-0). The ilution of the electrolyte is at a relative density of
1.28. The lead is known as the active material.

When sulphuric acid is in an aqueous solution (mixed with water), it dissociates into charged ions H" and SO4

The spliting of the electrolyte into these parts is the reason that a charging or discharging current can flow through te
liquid
The chemical eaction takes place between the three chemicals in the battery. In presence of H,SO, the electrons from
one group of plate collect on the other group of plate.
The voltage of a cell is created due to the ions (charged particles) being forced into the solution from the electrodes by
the solution pressure. Lead will give up two positively charged atoms, which have given up two electons, into te
liquid

.This flow of clectrons is continuing until there is insufficient in balance of electron to create a 2 volts pressure berwen
two groups of plate.

This results in a pressure of 2 volts between the terminals of the battery cell. If two terminals are connected by a cunu
the clectron will flow.

After a certain amount of current has been withdrawn, the battery is discharged or dead.

When it is discharged, it is not capable of delivering any additional curent. It is then charged

The charging reaction at the negative electrode

PbSO4+ 2e+ 24. Pb+ H,S04

The reaction at the positive pole is:

PbO+ H2 SO,+22H*
PbsO 2+2H,0 -

naln
ed
Hlati

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 (MSBTE Sem-VI) Automobile Electrical and Electronics System
omobile Engineering 5-11
FAUnO
mical reaction takes place while the battery is charged and discharged:
Theche
2H,50, Pb Pbso + 2H,0 + PbSO Q
Pbo,
Lead-peroxide
Sulphuric acid Lead Lead Sulphate Water Lead Sulphate Energy

(
Electrolyte
Anode+ Charging -Cathode

2e Supply

H2SO4

so

4H
---
2H,0

Fig. 5.32: Lead acid battery charging

sulphate (S0,). The hydrogen
acid (H,SO) is split into hydrogen (H) and
discharging of battery the sulphuric (PbSO,) and water.
During combine with part of sulphuric acid to form lead sulphate
(PbO) which
liberate at the lead oxide During
lead sulphate (PbSO).
librated at the spongy lead plates (Pb) and combines with them to form
The sulphate is plates.
absonption of SO, by the sponge lead
process the electrolyte becomes dilute because of the
this plate again
The lead sulphate on the
charged, the chemical reaction shown above became reverse. electrolyte
When battery is sulphate on other plate is reduced to
spongy lead (Pb). Thus the
converts to lead peroxide and the lead

becomes concentrated because of

increase in H,SO4
chemical energy into electrical energy
electrical energy into chemical during charging and
Thus the battery converts

during discharging.

so

mmnunnnn4 Chargag
Dichargng

FIg. 5.3.3: Chemical

reaction in batteries

5331 Factors Affecting Battery Life

improper electrolyte Level

CoTosion of terminals and conductors

3. Overcharging

TeciKauledgi
P
Cations

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 Automobile Engineering (MSBTE Sem-VI) 5-12 Automobile Electnical and Electronics
System
4. Undercharge/ sulphation
5. Poor mounting
6. CyclingB

5.3.4 Methods of Rating of Battery (Characteristic of battery):

MSBTE S4:SI6:W-18.
S-19

9Definerating ofBattery S14)

Explain battery capacityand rating

QHow batteries are raled? Explain testing of lead acld battery. Elaborale procedure of festing. 16)
W-18
Axplain Fatng ofBaltery.recommended by SAE

The battery rating are recommended by Society of Automotive Engineers (SAE) and is defined as lighting
ability of
a
full charge battery.

(a) Ampere Hour Capacity

A battery's discharge rate capacity is usually expressed in ampere hours (Ah) and is determined by the current that
can
be supplied continuously before the voltage falls below a given value (usually 1.75 volts per cell) for a continuous discharge
period which is usually either 10 hours or 20 hours. Thus a battery rated at 40 Ah should be able to continuously provide
4
amperes for a period of 10 hours or 2 amperes for 20 hours if fully charged.

Types of Rating of
Battery

1) 20-hour rating

2) Cold rating

3) 25-ampere rating
4) Twenty minute rate

Fig. C5.2: Types of Rating of Battery

1) 20-hour rating (in ampere-hours)

equa
It indicates the lighting ability of a full charge battery. It is obtained by discharging the battery at a cument rite
1/20 of the manufacturer's ampere hour rating.
rate that 1.15 md
.The curent batery dielivers continuously for 20 hour after which cell voltage shonld not drop below
battery temperature is 80°F

2) Cold rating:

It gives an indication of the cold weather starting ability of the battery.

below 1 vol.
The number of minutes of a6 volt battery can deliver 300 ampere at 0°F before cell voltage drops

3) 25-ampere rating:
L75
voltag
t measures the battery performance at a moderate constant curent output at 80°F to a final limiting
voltucell. It is the ability of battery to cary electrical operating load when generator is not working
TeanledyiN
Blitatina

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 Artomobile Engineering (MSBTE Sem-VI)
5-13
Current: Automobile Electrical and Electronics Systemm
4Reserve
capacity is a system use now on all new
SA at 2980 K to a final batteries. This
volage of 1.75 V per is expressedlas
as a time in minutes for which the battery
cell. This provides
if the ging
charging system docs
does not work. Typically an indication of how lor
the car long the battery can run
a 44 Ah battery
has a reserve capacity
Twenty minute rate: of 60 minutes.
5)

Itis th amount of current a battery can deliver continuously

he
temperature of 27°C maintained during 20minutes without
15. A at the start of dropping the cell volagc below
the test
Example: A carbattery is rateda 300 CCA battery.
Bxplanation : It meansthat, the battery
is capable of supplying
300 ampe
amperes of current for a period of 30 seconds,
while maintaining at least7.2 volts across the terminals
of battery having tempera
a perature of -18C
(a) Coldcranking battery:
Battery is given a rating that inaicatcs their perfomance
at high curent output and low temperature.
means that a battery is capable of supplying at A rating of 170
A means a curent for one minute
at a temperature of 255K when cell voltage falls
14 volt. The overall power output of a battery is much more
when deliver for longer time because
reaction at a certain speed. of rate of chemical

r 2.2 A for 20 hrs.

25 Afor60 minutes
170 A for 1 minute

20 hrs.
Fig. 5.3.4

The above Fig. 5.3.4, shows comparišons of Discharge characteristics of Cold cranking battery, Reserve capacity,
Ampere Hour Capacity.

D) Internal Resistance:

.A perfect voltage in seies with a resistor is shown in figure. This

fig shows that the terminal voltage of a battery drops
when a load is placed across it. When a current is drawn from
the source a voltage drop across the internal resistance
and is calculated as

R U-V)/I
Where, U = open circuit voltage,

V on load voltage,
ana I Cument

-Intemal
resistanca

Load
Perfet
voltage
source

Fig. 5.3.5 Votage load connected in series.

Tedh
Taralei
atios

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 Automobile Electrical and Electronics System
Automobile Engineering (MSBTE Sem- 5-14

(c)SelfDischarge:
on temperature and
The battery will be discharge without the extemal source or circuit. It dischargc ratc depends it
increases with increases with it and the age of battery.
forms short
The sclf discharge rate is caused due to the change in chemical reaction process between the grid material

circuit betwecn antimony and active material ie. lead peroxide

5.3.5 Capacity of Battery OR Specification of Battery
MSBTE: S-14.S-16

O.Define Battery capacity 14 S16

The capacity of battcry has been defined as the amount of curent it can deliver.

The maximum amount of curent that a cell can furnish is dependent upon the following factors:

1) Number of plates

2) Area of plate

3) Temperature of electrolyte

4) Quanty of electrolyte.

About 1/10 m of the surface plate must be in contact with an electrolyte to produce 40 to 60 ampere of current. 6 volt

passenger car battery have 15, 17, 19 and 21 plates per cell, the 12 volt have 7,9, 1l and 13 plates per cell depending
upon the size of the battery.

There is always one more negative plate than positive plate.

5.3.6 Types of Battery Tests:

MSBTE:W5
aEnlitthediferenttestsofbattery Explainspeciticgravitytestofbateny
Types of battery tests

0 Specific Graviy Test

i) Open Circuit Voltage Test

(m) Light Load Test

(iv) High Discharge

Test

Cadmium Test

Fig.C5.3:Types of Battery Tests

0 Specific gravity test

This can be done by the use of 'hydrometer contained

in a syringe. The electrolyte is drawn up
into the syringe byu
bulb and the hydrometer float sink to a greater
electrolyte.
or lesser extent according to the amount
of sulphuric acid n
u
Teckled
t
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 Automobile Engineering (MSBTE Sem-V)
5-15 Automobile Electrical and Electronics System
an instrument used to measure the specific
gravity of the clectrolyte for an uunsealed battery which
jves a fairly good indication of the battery's state of charge.

hwdrometer as shown in Fig. 5.3.6. Contained in a syringe consists

A hydr of a barrel type glass tube and rubber bulb at une
with a graduated scale marked on it.
top

The glass tube

contains a tloat and lorms a reservoir for the test clectrolyte.
Squcezing the rubber bulb sucks electrolyte
reservoir. The hydromeler float sink to a greater
eto the or lesser extent according to the amount of sulphuric acid in
the
clectrolyte.

The height of float

in a glass Sinks in the test electrolyte indicates its relative weight compared
to water.
The rcadings are
noted from the scale by sighting along the level of the clectrolyte
,
The specific gravity of the electrolyte decreases as the battery discharges.

,Measuring the specific gravity of an electrolyte by using hydrometer gives a good indication of how much charge the
battery has lost.

Temperature correction is needed because specific gravity changes with temperature.

Suction bulb

Float
Hydrometer.

Electrolyte
Outer tube

Pickup tube
Fig. 5.3.6:Specific gravity test of battery

During discharging the chemical reaction takes place and the electrolyte becomes dilute to formation of water. So the
Telative amount of water and acid is determined by the specific gravity test

The of the clectrolyte is affected by its temperature hence the tomperature of the clectrolyte is also
specific gravity
ecorded by a thermometer. The specifc gravity test should not be made while the batery is gassing and immediately
ater water added to adjust the electrolyte level otherwise it will ffect the readings.
T the hydrometer reads 1.280, it indicates that the liquid is 1.280 times as heavy as water and at the reading battery is
fnly charged. The
reading of bydrometer shows the condition of the batlery at 27°C (80F) according to following
table.

Reading Condition

1.220-1.230 Fully charged (100%)

1.200-1.210 3/4 charged (75)

1.175-1.185 1/2 charged (50%)

1.150-1.160 1/4 charged (259%)

1.125-1.135 Very litle charged

1.100-1.110 Discharged

Tec
Kaeled
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 Electronics Sv
Autormobile Electrical and
Automobile Enginering (MSBTE Sem-VI) 5-16

Gi) Open clrcuit voltage test

cireuit in Such a way that the
test conducted by use of voltmeter. The battery is connected in the
The open volt is the
and when Ine voltmeter gives the
with the help of voltmeter
posiuve teminal of battery to the negative terminal
indication of 2.1 volts then we say that the battery cellis about fully charged.
to a charge
voltage which is consider be equvalent
to
When the voltmeter indicates a charge of 0.01 volt of open circuit
gravity of an electrolyte
can be measured indirectly
of 0.010 in the specific gravity of the clectrolyte. Thus the specific
with a voltmeter also.

5.3.7 Salient features of Maintenance free battery:

and charge cycles.
Maintenance free battery is one that experiences little gasing during discharge
It docs not reguire addition of distiled water to the battery cells.
Generally they are provided with built-in charge indicator.
material is minimized.
These batteries resist overcharging at high temperature. Corrosion of the active

Construction:

The maintenance batterics have cell plates made of slightly äiferent material. Calcium or strontium is used to
fre
strengthen the plate grids instead of the antimony used in conventional batteries. These batteries use about 0.1%
calcium instead of antimony.

i) When overcharged, calcium will use only 1/3rd of the water that antimony does.
im) Maintenance free batteries are sealed except for small breather holes to prevent gas pressure build up in the case.

This is because the lead and calcium combination is susceptible to damage from even a small amount of dirt or grease.

5.4 Starting System

MSBTE D
SI1
Q.What are differentcomp
tomobile s1aring systEm
W10
OEXplain working ofstarting system

The starting or cranking system consist of a starting motor,

battery, control switch and interconnecting wiring.
performance of all these components must matched he
be against engine requirements for satisfactory
service.
The starting motors are mostly of direct current
series motor. These convert the electrical
to mechanical energy by rotating the armature shaft. energy supplied by the battergy

A drive mechanism couples the shaft through

a pinion and flywheel ring gear
of (a) Motor unit (6) Drive unit. to the engine. The starting motor cos

5.4.1 Requirements ofthe Starting

System:
An internal combustion engine
requires a combustible
mixture of air and fuel,
the minimum initial starting compression stroke for the
speed about 100
rpm in order
igniou
requirements are less for to start and continue running of a These

this minimum speed is

obtaining starting speed
to attain. This is where
the electic starter comes in. Theana
veicnentof
again dependent ona number
of factors, such as
)The rated voltage of the
starting system.
() The lowest possible temperature
at which the engine limit
temperature. can still be started. This
is known as
) The torque required to
crank the engine
at its starting limit
temperature (including
the inital stalleu rque)

TecKa
PB

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 (MS5IE_Sem-V 5-17 Automobile
gineering
Engine Electri
andElectronics
ALOmODIe characteristics. onicsSystem
battery
Thevolage dropå the battery and the starter.
rop between

Th The
startce to ring
gearratio.

oi characteristicsofthe star
starter.
The
i) ranking speed eof the engine at the starting limit
cranking
minimum temperature,
1he
i) possible. starter as an isolated component
within the vehicle
not consideration. electrical
ts irlaris ofprime
purcuar
n of
system
importance for

any vehicle must fulfil the following criteria

in addition
system.
The battery
in
starting to the eight factors
The functioning. listed above
for its
eficient
service life and low
maintenance needs,
A
Long
operate.
)Continuous readiness to

stness to withstand starting forces, vibration, corrosion and temperature

cycles
lowest possible size and weight.
The
Components and Functions of Automobile Starting
54.2 System:
Components of automobile
starting system

) Battery

) Starter motor

im) Solenoid switch

v) Starter drive

v) Staring safety switch

Fig.C54
Batery : It provides necessary current to solenoid and starting motor for engine cranking
motor: It receives current from battery and converts into mechanical motion, rotary mtion for
"ee engine.
cranking

Sol
SWitch: It acts as an clectromagnetic switch with a movable core that converts curent flow into mechanical
movement.

as soon. s
"ter drive :t couples
engine crankshaft
armature with the flywhel during cranking and disengages armature with flywhel
turns faster than the starter pinion.
)Starting
operation if the transmission is not in Park or neutral
y Switch :It prevents starter motor cranking
position.

Layout and Working of Starting System

he switch. When the
stem has starting contacts in the ignition
fio nuy used in passenger cars and other vehicles
ignition START, the starting contacts close.
key is turmed against force pass the ON position to
spring
Thisconnec the battery. After the engine start and the ignition key
istelease
nng
ne starting- motor solenoid or magnetic switch to
force returns it to the ON position. This opens
the starting contacts.
Tedarulelgi
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 Automobile Engineering (MSBTE Sem-VI)_ 5-18 Automobile Electrical
ar Electronics nd
Sptem
On starting motors used with overunning clutches, a solenoid is commonly used to produce the cluteh. dem
shifüng
actiom.
The solenoid contains a pair of winding that are connected to the battery when the starting suibat
chis closed.This
producs a magnetic field that puls a plunger in.
clutch on the armature shaft
The plunger movement cause a shift lever to move the overunning
To dstrbutor
batiery tenminad
Solenoid
Solenoid
Bulihead
Swith Connedtor
Hold in cod Contacds

Pinger
Shit lever

atery
Pinion grition and
Flyheel Stater SWich

Sht
Collar

Clutch Pinion
Cranking
Compression
motor
spmg Batery

Fig.5.4.1: Layout of Starting system circuit

the flywheel teeth. At the same time, the plunger movement

This shift the overunning clutch pinion into mesh with
forces a heavy switch to connect the starting motor directly to the battery. Now,
cranking begins. Fig. 5.4.1 shows the
sequence of action. Fig. 5.4.1 is a wiring diagram of a starting motor system.
to pull the plnger in.
The solenoid has two windings, a pull-in winding and a holdin winding. They work together
has a sliding pole
Fig. 5.4.1 starting system which uses a separate starter relay (magnetic switch). The starting motor
starting motors.
shoe that moves to shift the pinion into mesh. This action is perfomed by solenoid mounted on other
the starting-motor
This combination of windings provides sufficient magnetic strength to mesh the pinion and close
switch.
core Conscquendy, as te
After the pinion is meshed and the switch is closed, lss magnetism is nequired to held the in.
This reduces
switch closes, the pull-in-winding is shorted qut, since it is connected between the two solenoid terminals.
the load on the battery during cranking.

5.4.4 Bendix Drive:

MSBTE BSH145WE14W-15, S-16, W-16.S17AZ, SHEW-18.S19

Explainfünction of Bendik orive instaring systemNTn ane 14 W-14

Explain thefunction of Bendixdive
in
slarter system W15, S-17
nan wofkngo Bendix drive úsed in'stating sysiem with neat skeldh S-16, W-16

Explain with neat sketch Bendix dive used n staring system W-17
(S-18, W-18)
Explain the working ofBendix drve yWtineat sketch
Explain the construction andWorking of Berndit o 1
unun
This type of drive depends upon the inertia of the drive gear to produce meshing, Inertia is the property which all
have that resist any change in motion. When drive gear is stationary, it resist any force which tends to set it in motion

TechKaouledgi

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 Se
(MSBTESem-VI)
Engneering 5-19
omobile
ALICIO tomobile
to engage starter pinion with the flywhe Electrical
eis used andElectronics
withtthe armature starting Sy
fastening this unit motor shaft,
For partsare free from armature shaft and drivehead. thedriveheadiskeyed
, ther to theend
he ccted through
connccted through the springwhich
altached
of amature
shaftwhile
They
are only to thehead
andthesleeve
current passes into
Cum the starting motor the
armature carying
When the threaded sleeve.
beginto
tum at
pinion.
efect to th ful speedcausing
ming
, Although the
pinion is tume et itis moved forwardby
to its inertia of rest and unbalanced weight.
uc toits
thespiral thread
the transmission
of

iywheeldue tillitengaged
with the
is revented teethof
Furthermovement of pinion by a collar attached the
on thesleeve,
thee
engine flywheel, the flywheel rotate and because
mesh with engine starts, of thispinion
startrotating
Threaded as it is
dleeve Pinion gear
Spring
Drivehead
Armature
Shalft
ommutator
and
AmaTure

Coller

Balancing weight

Flywheel

Fig.5.4.2: Bendix drive

.The starter pinion and flywheel gear do not remain in mesh but are automatically disengaged by
soOn as the engine the Bendix drive as
start because in comparison to the rotation
of starting motor, the engine rotate the pinion much faster
after it start causing damage to the starter motor.

This disengagement is affected dlue to pinion rotation much faster

by the engine in comparison to the rotation of starting
motor at the time of engine actually start

Therefore the starting motor will be also protected due to pinion meshing
out of the 1lywheel gear because of its
SCTewing back on the spiral threaded slceve when the
starter switch is relcazed by the operator.

5.5 Charging system

5.5.1
Function and requirements of Charging system:
MSBTE W-14 S-15. W-16, S-18
(W14)
Sjatethe need of charging system.
IS15)
yis necessary to charge automobile batery
Statethe W16,S18)
ateithe needotcharging syster
well
curent to the starter at the time of starting as
The batter
direct current. The battery has to supply the
storage of
asto th
to the various accessories of automobile. depends upon state
current flow to battery
Generator constantly. The rate of charging
pro curent to charge battery
of charge of vides
battery. happen that run of vehicle is not
certain circumstances it
1fsufiei
batteryis
un down the charging rate will be
higher. Under
discharge due to frequent
use of starter, prolong
period of parking light

t to charg been
ON or age the battery which has car radio etc.
by the use of other accessories like,heater, blower, Tefaenledgi
Pliatisas

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Automobile Engnering (MSSTE Sem V) Automobile Electrical and Electronics System
5-20
always in charged condition there
Duc to prolonged use the charge of battery is decreased. Therefore to keep the battery
is a requirement of charging system.

Components of Charging System:

which ensures that battery remains in charged
Charging system is a part of a overall electrical system of motor vehicle
statc in any given situation. It comprises of following:-
phase recifier that is
Rectifier- It is full wave three
1) Battery: Gets charged as it avails DC supply from rectifier 2)
used in cvery vehicle
regulating ficld curent
3) Regulator: It regulates curent and voltage to the batery by
electrical energy as per
rotor-Converts mechanical energy made available by engine into
4) Altermator: Stator and
the principle of induction.
5) Relevant Electric circuit

5.5.2 Alternator:
MSBTE S16.W-17. S-19

advantages (S-18
Expain construcüonand working o.altenator state its
otaltematoEwith nedt sketch.
W-7,19
EXplain constructionand working
Alternators are much smaller,
alternator is used on vehicle to charge the battery and operate the electric circuits.
An
dynamo.
lighter in weight and produce more curent than
stationary set of winding. Solid state diodes used to
convert AC to DC
The altemator has a set of rotating pole and a
and brush assembly.
voltage. The alternator is made of stator, rotor, slip ring

5.5.2.1 Worling Principle:

generator.
Alternator operates on the same fundamental principles of electromagnetic induction as dc.
in the
which cuts a conductor induced a flow of electric curent
A rotating bar magnet furnishes the moving ficld
conductor. This is how the altermator produced.a current.

5.5.2.2 Aternator Components and their Funetion:

Components of
altermator

) Rotor

i) Stator

i) Stator vinding

) Field winding

v Brushes and Slip ring

vi) Housing

vi) Diode Rectifier Bridge

ii) Cooling Fan

Flg. C5.5

eliroth

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 (MSBTESem-VI)
Engineering 5-21
obile Automobile
Electrical
a Electronics
magnetic field when ficldwinding caries current. System
Treates

ides a path for

magnetic flu usinglaminatediron core
and holds stator
Stator. gener lectricity by cuting the rotor
winding.

Salorwinding
winding
:t generates the magnetic lines of flux.
magnetic flux.

: It
i The ovide a meams of maintaining
Slip ring: electrical continuity
Brushes and between stationary
s-battery and field winding through regulator. and rotating
rotora
e rotor and stator parts. It nolds rectifier and
supportsthe
Housing :t regulator.
Rectite Bridge : tis used to rectifier current output of AC generator.
Diode
i) Fan:It coolsthestator and rotor and diodes of altermator.
Coo
vij
Construction:
55.2.3

dan of an altemator is improved by placing the stator

operation
The and rotor assembly inside the iron frame
conducting path for the magnetic line or housing,
which provide a of force.

yoltage can be increased by increasing stator winding into number

of coil. A stator consisting
of one winding of
wire. Most altermator use three winding in y shape, called 3-phase.

.An altemalor consists of a rotor assembly (held winding), a stator assembly (arnature winding)
and a rectifier mounted
in a housing. But the main difference between the D.C. generator the amature rotate
and field winding is stationary
while in altemator ficld winding 1s rotated and the armature
conductor is stationary. This is called stator
as and field
winding called as rotor.

The housing made of two piece of die cast aluminium which is light in
weight and good heat dissipation property
bearing support the rotor assembly is mounted in the front and rear housing

Similarly stator is clamped in housing- The three windings are joined together at one end and
other end connected to
rectification asscmbly.

The field winding assembly consists of rotor shaft winding around an iron core, two pole pieces and slip rings. The
otor shaft is pressed into the core.

'The slip rings are held the two brushes by springs and are connected through a switch to the battery. The recifiers and
aodes ae presed in the slip ring end head or heat sink and are connected to the stator leads.
Working

aCn the field winding rotate a magnetic flux cut the magnetic lines produced by pole (N and S) and e.mí.is produced.
1his eamí.can be
colected by brushes from the slip rings. The nature of this e.mf. is A.C. So it is called altemator
OwCver curent generated in the coil is changed to direct curment D.C. by a
the alternating rectifier
just before output
and if generated in the coil.
OTEvolving a coil, a magnet (magnetic flux) is rotated inside the cirent can be
coil,

Thelarg
Volume of curent generated in the coil, the more coil will heat up due to current flow.

Forthisreason,,cooling is better if the coil is cquipped on the exterior of the generator.

altemators for automobile utilize generating coil (stator coil) with an internally rotating magnet (rotor
,all
col).

Tecfanlelgi
llatlas

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 Som-V 5-22 Automobile
(MSBTE El tricaland
Engineering Elertrorica.
From beatey
Automobilo Dodo Magnet Sptom
5tatcr

To
loctrc dr
Stp rthgs

-Diod

Fig. 5.5.1a): Working principle of alternator

bracket- 12-pole rotor and feld
Sip tng end
wirding assembly

Buit-in output- Fan

regulator Stator
Pulley
sink
in heat

Ball race
Cover Sip rings bearings

Brush gear- Rectifer pack Drive end bracket

exploded view
Fig.5.5.1(b): Alternator

Advantages of
Alternator

curTent.
(1) It limit its own

regulator required.
(2) No currecnt
running condition.
charge when vehicle is in
koeps the battery
3) t
Charging of Battery by
Alternator:
5.5.3 MSBTE: W14,W15.S18
W-14

constructional detall of charging

system used in automobile
S19
W-16,
Q.Explain the Automobile
Descnbe constnuction and operation of charging system used in
Q
turned ON, the iet rotor
generator. When the ignition switch is
charging circuit of A.C.
Fig 5.5.2 shows the produces the magnetic
field of the rotor.
regulator. This current
cuTent from the battery through
the voltage anged ino
altermating curent is enu
This
induced in the stator winding.
the roator is turned by the pulley, curent is
As
direct curent by rectifiers. vaue.
volliage a
used to limit the generator
ne voltlage depends upon the rotor speed. A voltage regulator is
barteny
volage generaled by the alternator is greater than battery
voltage, it will charge the
the

ctiani
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 Engineering (MSBT em-VI)
5-23
AutomobileElectrical
Stotor andElectronics
Rectifers
Wndings System
Heal sink

Baiery
thermal

Igition End frame

Ground wire-

Fuel
VoNiage-
regulator lgnition»

Rotor Amature

Rolor
windng

Fig.5.5.2: Charging circuit of A.C. generator (Altermator)

battery voltage then the battery wll be díscharged. This situation

than the battery
lessdhan will also ocur when the generator
If armature is
stationáry. To avoid this a cut-out is used to isolate the armature from the battery.

System
56lgnition
This is the system by
means of which spark is a provided in(S.) topetrol engine ignite the compressed air-fuel
mitur. Thissystem supplies a high-voltage surge ofcurent to prodace spark at the spark phug Ep.
according to the firing order of the engine to produce
The spark is produce at the exact time in the vañious cylinders
the combustion chamber.
maximum useful energy during the expansion of combustible gases within
transistor switching or it may use a capacity
ignition system may be of conventional design, it may use high-energy
The
discharge system.

5.61 Function and Requirement of lgnition System:

electrodes of the plugs at the comect timing.
L hshould provide good spark betwcen the
engine speed.
2 Itshould function efficiently over the entire range of

tshould be light, effective and reliable in service.

should be compact and easy to maintain. the spark discharge even
in lean
electrodes is required to affect
spark plug
large voltage across the
CnLy
mLxtures.
gap
combustible mixture across air
Suply energy required to ignite the engine load and
speca.
timing as per
be capable to advance or retard ignition position.
Id
&Efeciveto circuit at appropriate
time with
respect to crankshaft
ggertrigge the primary
S52 Types of Ignition Systems

0Batryignitionsystem
Conventional Transistor assistedd
(b)
Magneto ignition
system
9 Eectronic
ignition system
TechKaraledgi
9 Capacity
discharge system loatioas

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 Engineering (MSBTE Sem-VI) Automobile Electrical
Automobile 5-24 and ectronics
Systerm
1. Conventional

2. Distributor (Electronic)

(a) Mechanical and yacuum timing advance or (b) Eleetronic spark timing

3. Elcctronic (Distributor les)

Ignitlon Systems

Magneto ignition Coil ignition

system system

Electronic DistributorDistributor less Direct

Conventional CDI ignition
ignition igntion ignition

| Conventional coil Electronic Computer controlled

ignition system ignition system coil ignition system

The main task of an ignition system is to provide a precisely timed spark with suffcient current to ignite the
proper fel
to air mixture. Regarless of any type of system, any ignition must have the following elements:

() Adequate Electical Supply- this is the vehicle's batery, which supplies the initial
curent to startup the vehicle.
) An Tgnition Coil capable of augmenting 12 to 14 volts to 6,000 to 35,000 volts.

c)Distribution of secondary voltage.

(d) Electrical wiring to distribute secondary current from the ignition
coil to the spark plugs. Spark Plugs used to create the
spark that ignites the air/fuel mixture.

(1) Battery lgnition System

MSBTESS16. W-17
EXplain wilhneatsketch.theCrcuit diagram.atsparkignitiog
(S14
QExpain batter igpiian systëm o four cyinder

eExplain bøtteryjgniton systëm with

The battery ignition system consist of batery, ignition

switch, ignition coil with
a ballast resistor, distributor housing
contact breaker points, cam, condenser, rotor and advance
mechanism, spark plug and low
and high tension wiring.
The ignition coil consist of two coil, primary coil having 100
to 200 turn and secondary coil
having 20,000 urm.
The primary winding is connected to the battery through
an ignition switch and contact
breaker point
While secondary winding is connected to spark plug through
distributor.

Ted Ka
7
ilaties

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 ering(MSBTE Sem-VI) 5-25
tomobile. Automobile Electrical
Secondary and Electronics System
Wdg

Distrbutor
Sparkplug

Primary
Wdg

Ballast -D1
resister D
ignition switch Rotor
D4
Cam

Contacd breaken
2 Battery

Fig.5.6.1:Circuit diagram of
spark ignition system

resistor orovided in series with the primary winding to regulate primary curent and passes
ballast more curentin
A starting.
circuit during
prinary
speed operates
operates the
at camshaft speed r
the contact breaker and causes the breaker point
,Atating cam thecontact breaker point is closed, the current flow primary
to open and close.

gnition switch is ON and in winding and builds

When the
magnetic field
up a
contact breake
eaker point open, the cuTent flow in primary winding is stopped and the magnetic field
so as the
Assoon secondary winding and induce a voltage which is accomplished by
the a curent
collapse, cuts acrossi
primary winding and induced voltage in this as wel as in the secondury winding
magnetic field also cuts the
This action producing it. Thus effect of this is to slow down the build up
primary winding always opposes the
The voltage in
breaker point closes.
the primary winding when
of the curent
in
consequently lower voltage in secondary circuit,
to this continuous process a slow building up of the magnetic field
.Due causes sparking at breaker point. This arcing
increases wear and redoce the
Tesult slow collapse of magnetic field which

life of contact point.

the contact
condenser in primary winding across
prevent arcing and this can be achieve by using a
to
Itis necessary cument flow in primary winding is
stored and it become charged.
contact point open, the
reaker, when the
thus cause to quick collapse
of magnetic ficld
back into primary circuit in reverse direction,
immediately
t discharges plag through distibutor.
secondary circuit which supplies to the spark
md a high voltage is build up in
the ignition of charge in
occur acros the spark plug gas cansing
breakdown voltage a spark
ueis voltage is higher than
combustion chamber.

LIinitation
switching capability of the
in the curent
decrease due to limitations
v engine speed increase, the primary
voltage
he
breaker the
system. buildup of the current in
of the time available for
As the engine shorter because
increase, dwell period become
Ped
anary coil and
stored energy decreas. plug insulator
decrease.
side-tracking across the
Douctothe
highssource of system is sensitiveto because of continuously
Or iimpedance in the contact breaker point
lhcreased reliability of the
cureat causes rapid reduction in the life and
sabject es a rapia
dtoelectrical aswell as mechanical wear. TedKaenledge
Iatlans

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 Automobile Electrical Electrorics
Sem-VI) 5-26
Engineering(MSBTE System
Automobile

(2) Magneto
Ignition System
type (2) Rotating armature type.
of two type (1) Rotating magnet
This system is HMSBTE:S13

system.
Explaig in brief 'Magneto ignition'
Q.
Rotating magneto.type

) Low tension magneto

clectric generator.
Magneto is a special type of
current in primary winding
which produce and supplies
consist of a magneto instead of a battery,
It Windings and a rotating magnet assembly.
having primary and secondary
magneto consist of a fixed armature
The and a, high voltage is produced iin the
magnet rotate in fixed armature, current flow in primary winding
When the
distributor.
to the spark plug through
secondary winding. This high voltage is send
speed.
by rotating cam at cam shaft
Contact breaker point is open or closed
generated by magneto is very low.
During starting cranking speed is low and curent
is required.
hence for starting purpose a separate battery
As engine speed increase, current increase,
magnet type.
The magneto may be rotating armature type or rotating
used for sport and racing cars, craft engine.
The magneto is best suitable for high speed, therefore

) High tension magneto (Rotating armature type)

and distribute it to the various spark plugs.

It generates high tension electricity within itself

The armature, along with primary and secondary

windings resolve in a magnetic field set up by the permanent magnets.
the
The windings or coils passes through the magnetic ficld
generates the current and when it reaches its maximum,

contact point breaks which is filtered in the primary circuit open.

winding so the voltage is multiplied
At this a current is induced in the secondary winding is more than the primary
tension curent is collectedby
The end of the secondary winding is connected to a collector ring from where the high
transmission to the spark plug
the high tension lead through a carbon connection and fed to the distributor for onward
winding insulating from
A safcty gap across the terminals of secondary winding and the ground protects the secondary
disconect from
excesive voltage effects, which would, occur due to incomplete circuit if a high tension leads to
spark plug.

Disadvantages

(1) Centrifugal force affccts the windings.

2) There are many rubing contacts to collect the curent from the moving armature.
6) Only two sparks per revolution are produced

Applications: In racing cars, motor cycle, scooter, ctc.

TeciLeled

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 domobile Engineering (MSBTE_Sem-Vn

A 5-27
Automobile Electrical
and Electronics System
Spark phugs
Distrttot

Cam

Rotating
magnet

Contact breaker

Fig.5.6.2: Magneto ignition

system (Rotating magnet
type)
Diference between Batery lgnition System and Magneto Ignition System:
MSBTE: S-15
system
OCompare batery ana magnelo.ignition

Batteryigniton system
Magheto ignition system
Current for primary circut is obtained from the| Current for primary circuit is generated by the magnelo.
battery.
A
2 good spark is obtained at spark plug at low During starting, quality of spark is por due to low speed,
speed. so extra battery is needed for starting.
Starting of engine is easier. Starting of engine is cifcult.
3.
battery needed, hence no prvblem of battery discharge.
Battery is most important, Impossible to start| No
engine when battery is discharge.

Require less space.

Require more space.

.
increase.
Spark intensity improve as the engine speed
intensity falls as the engine speed rises.
Spark
More costly.
Cost is less.
scooters etc.
Used in racing car, motor cycle,
L&Used in bus, cars, truck.
Electronic Ignition System
MSBTE S13.3W-14 W-16.S-18.
W-18. S-19

cropic (S13W-14)
elecropic igniton s neat sketch
Explain
(W16)
neat skE anito
with neatsketch electronic ignitlon system
(s-18, S.19)|
workingofelectronicignitionvstem
he y W-18)
ae dvantagesofelectronicignitionSystem.
ecaledgi
Publicatisns

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 (MSBT_Sem-VI) 5-28 Automobile
Engineenng Eled
Automobile alandElectronica
usc of brcake points to interupt
is the is
mechanical system
stem is the
-voltage Sydem
disadvantage of the subjcct to n chanical wecar high-curren
coil; the points are where they
, The
primary
windingofthe t the
the contact
o surfaces from the constant sparking.
ride
ntoogen thtongh
the burming atat andshut,
axidation and aa
vell as
to compensate for wear, : opening of thecontactbreak
ijustment
ngularadjus ich responitle
They
reguire mechanical variations is
subject to
timlng, is
for
spark contact servicing and to pr ide longer ignition system life
froquentibrcaker and be
avoid comsiste
necdto rease fuel consumption and
increa ocarbon emissions sisteacy
The avoiding the
power loss and from ok
thereby, theer
concepts using solid state d
fining, gnition system
new ignitio h aim atpartial
developmentof or totalsolution
led to the ntional ignition system. ation
conventio ts
cncountered with the
oblems
System
Electronics lgnition
Princlpleof
conventional point type lgnition System with a small dif
Electronics
Ignition system s
is similar to
tem is
Bectria
Electronic control unit which opens and close the primary circuit instead
provides with stead
ofcontact
Ignition system is
Contact breaker point
breaker point as in
contact breaker.
distributor instead of
used in the
system atimer is
h this tnggers the ignition module called electronic
be a pulse
generator or Hal-enect swucn wnich eloea
ignition
This timee may

Control unit

primary contain transistor circuit whose base cuent is tiggered OFF and ON by a timer nds.s result
This control unit

stopping of the primary curent

in the starting and

Electronic ignition system

Construction and Working of

Construcdion:

. Elctronics lmnition syatem is having

two circuits Primary and Secondary circuit. Battery. primary winding, ECU and

the timer forms primary circuit.

Whercas socondary winding, distributor and spark plug forms secondary circuit
A tinr is employed in the distibulor instead of contact breaker. This timer may be Pulse generator Or Hal- efiast
Switch which Thigers the Ignition
module also called as electronic control unit.
Working:

ms control unit primarily

contains transistor circuit
whose current is triggered off and on by in tho
stopping and timer wnicn resu
starting of the primary
circuit.
The secondarycircuit
worked in the similar manner
as in conventional contact
1. wbeathe magnetic breaker ype
field collapses
it induces curent
TEuls indevelopnent cuTent in
in the secondary winding having more number of turns.
of very high
voltage necessary n
to generate the spark
at the spank plug

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 Sem-VI)
Engineening
(MSBTE 5-29 Automobile
Electrical
nobile Electronic and Electronics
System
Ignition coil control unit
Switch
Spark plugs

Sensor coil
-Battery

Armature Distributor

Fig.5.6.3:Electronic ignitionsystem

Electronic Ignition
System
Aantages of
part, it
translate tthe control and reliability impossible to achicve any mochanical systenm.
No ine part,
moving

starding with cold engine. Fast

build up of output voltage
Better

possibility of arcing at spark plug. Spark plug fouling is greatly recdaced.

Is
timing.
Longer life due to stable
output voltage which is attainted in a very short time and with a very limited discharge, resulting
Podce a maxzimum
regular engine running, even with
dirty/foul spark plug and wide, plug gap.
in

C.B. point, Cam, etc. which expose to wear and tear.

Nochange in ignition timing due to absence of
1. High volage at secondary circuit throughout engine speed range.

Input current and output available voltage are constant over a wide speed range.

Disadvantagas of Electronic Ignition System.

This system is more costly due to more components.

2 Batery is necessary for starting.

Diference between Battery Ignition and Elecironic Ignition System

Elëctronicignition SYstem
NO. Battery ignition system
distributor.
Contact breaker is used in distributor A timer is used in the

Less cost. More costlier.

Compact, less space required

Require more space.
consistency of firing.
Power loss occurs. Avoid a power loss and

starting.
5. Battery required for
Battery is most important. Inmpossible to start engne
when battery discharge.

Spark intensity Spark intensity constant

falls.

5 LIghting
System
571
Introduction:
integrated to the front, rear,
signaling devices mounted or
BOs, 0 d automobile consists of lighting and
and
insomecases the
top of an automobile.
Ted Kaemledge
atlans

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 Electronics System
Automobile Electrical and
_Sem-V 5-30
Engineering(MSBTE
Automobile
System: safcly at night.
5.7.2 Function of Lighting operate the vehicle
to
illumination for the driver about the
the lighting system is to
provide
dri ver or peopie on the road
1) The purpose of information to other f travel. Beside this the
to convey direction and speed of
t
conspicuity of the vehicle and intended
2) To increase the travel and the
driver
vehicle presence, position
size, directionof vehicle.
dashboard and inside of the other dinvers and
pedestiane
illuminating instrument on the vehicie, alowing
visibility of the direction and sSpeed at
and increases the intentions regarding
roadway for the driver driver's
lights the and the
3This direction of travel,
vehicle's presence, position, size,
to sce a Emerpenr
movement in tratfic such as an
travel. priority of conveytn
warm drivers and indicate ambulance van used for ng
equipment to to an
4) The different lighting light with purple glass fitted
red
The blinker type of
vehicles usually cary.
patients

5.7.3
Requirement of Lighting System: withstandin
conditions of use and not
installed that under normal
light signaling devices shall be so
1. The lighting and
they may be subjected,
any vibration to which correctly.
that alignment can be easily set
Theilluminating lamps shall be so fitted
2 the vehicle shall be parallel
to horizontal bearing plane of the
signaling devices when fitted to
Reference axis of all light
vehicle.
specific instruction, with the vehicle unladen and
The height and alignment of lamps shall
be checked, in the absence of
4.
located on aflat horizontal surface;
symmetrically in relation to longitudinal median plane.
5. lamps constituting a pair shall be installed on the vehicle

6. The lighting fixtures housing and socket shall not be used as a ground returm
for any other electrical circuit.

5.7.4 Types of Lights

Modem vehicles uscs different types of lights for various purposes. The main lights are :

Types of lights used

for vehicles

1. Head lights

2.Parking lights

3. Direction-signal lights

4. Blinker lights

5. Stop lights

6. Back-up lights

7. Tail lights

8. Interior lights

Fig.C5.6

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 (MSBTE Sem-VI
utomobile Engineering 5-31 Automobile Electrical and Electronics System
Auno
function f head lights is to illuminate the highway road sufficiently to permit safc night driving. Generally
The hese
beams, one
o with high intensity to gives
ovided with two maximum illumination for night driving and other gives
seprovhe eround aand to the side of the road to minimize
ground
deflection to the glare when passing of cars on the road. Sometimes a
uscd which is of low intensity for city driving.
thirdbeam is
rdon to the head lights, low intensity parking lights are usually provided in the front of the car, either separate
,In o nat of the head lamps, and are used while the car is parking. For parking the car during dark, parking
3o
uils kent he
lightsare
d to provide a signal for other moving objects and thus avoid the accident.
kept ON

Direction-si lights known as "directionals", "blinkers", "indicators", or "lashers"

are blinking lamps mounted near
right front and rrear cormers of a vehicle, are
and used to indicate the direction in which the vehicle is to turn.
the left
give signal to the vehicles coming from the front or rear. In addition, some special signal
Thelights light are also used.

These
include a red signal light to indicate when the high beams of the head lamps are burning, to indicate when the
applied, to indicate that the oil pressurc is low, that the cooling water temperature
parking brake is is too high or too low
generator is not charging the battery.
or that the

Rack-up lights turns ON when the driver shifts into reverse. This closes a switch linked to the selector lever which
connects the back-up light to
the battery.
car is stalled on the highway or has pulled
.BEinker lights provide a means of signaling when the ofto the side.
biniing is much more noticable than a stcady light and provides a warmning to aproaching cars.
The
lights illaminate back of the car in
the night so that the other vehicles coming behind it are able to see it
,Tail
the night. Stop lights are also at the rear of the car and
,Tail lights are kept ON all the time when the car is running in
become ON when brakes are applied.
instrument panel lights, various
. To illuminate the Interior of the vehicle a various type of lights are used such as
Keyhole lights, map lights, radio dial lights, clock lights are also
warning indicator lights, and compartment lights.
provided in some cars.
Map-roadiog igh Glove bax light
instrumeni panel lights Dome or windshield
header ight fLuggage
compartnent
light
Underhaod light 7

Hoadihts Stop lights

-Tail Fghts
Backup ightss
License plate
ight
Comering lights and
ftront side marker Ights Ashtray lightsCourfesy Rear side
door lights marker íghts
Emergeny-repairs lighf
(With extension cord
into ighter socket)
Company)
lights on a vehicle (Ford Motor
Fig. 5.7.1: Interior and exterior
1. Head
Light
MSBTE W-11. W-13

W-11
the details of head lamp of vehicle with neatsketcn
Explain th
W-13)
pain the head lampof vehicle with a nealsketch
Head sealed beam type are mostly
filled type or sealed beam type. Now-a-days
Sed are either Incandescent gas
and a weaker low beam for city
driving.
beam for normal Geometry driving
A ghts are made to throw a high lamp system.
vehicles uses sealed beam head
of incandescent gas filled type. Now
elamps are

Tec Iavaleli
lcatiaas

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 Sem-VI) Automobile Electncal
¥Automobile Engineering (MSBTE 5-32 and Electronics
ronicss
System
Both lamps are alike and produce a straight hcad upper or "country' driving beam and a deflected
to er or "trafficC
beam in which the light from both beams deflected on one side of the road and slighuly dowinward
is
inimize
The traffic beam is affected by locating the traffic filament in a position slightly eccentric
ccentric with gare.
the center
cent of
the parabolic rcflector. the focus
of
The tungsten filamcnt is used in bulb of head lamp which turm white-hot when connected tobattery
and gives
Now-a-days halogen headlamps are used. These emit a whiter and brighter outlight
light than other sealed headlamn
A halogen headlamp has a smaller inner bulb filled with halogen
gas which protect tungsten
filament. The
airtight or hermetically sealed. The halogen lamp shown outercase
in Fig. 5.7.2(6).
is
Ught deflected
Pnsm by prism

Reflecor
Halogenifilled
inner bulb

-Dip flame Tungsten-

Manfilament
at focal point
lament
oT refector

A Strayight
Luight defiected
byPrism
Lens
(a) Head lamp main
and reflector (6) Construction of a halogen sealed-beam
headlamp
Fig.5.7.2
Aiming of headlight

The headlights must be aimed correctly

to the required direction to get proper
light on the road and to prevent
vehicle from accident. the

If the headlights are aimed too high or too low

they might blind an incoming
driver, causing the accident. Incomect
aiming of the headlight will not illuminate
the road properly:
1) A good main beam help the driver
for maintaining a rcasonable speed at
night.
2) To prevent dazzling of oncoming driver
of the approaching motor vehicle
by dipring the main beam.
3) To pickup the sides of the road side-illumination
should be provided.
4) To prevent dazzle to the oncoming
driver during particularly mistry
or hazy conditions the light about tne
horizontal should be cut off.

2 Tail Light and Stop Light

Each of these lights have their own function,

but forconvenience in design they
are usually assembled into a single

Karledg
Ted
ti

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 Sem-VI) 5-33
Engineering(MSBTE Automob
nobile Engin Electrical
ALUIOINODe
High beam
andtallights andEle
onics System

Instrument panel
ights

lnilon sirth
Light swteh and
rheostat
dinmer swtcth

Fig.&
.5.7.3: Headlight and tailligh wiring circuits, with headlights
on high beam
usually prescribe the stop light to be at least three times
Traffic laws larger than the tail
light.
light switch1may be of the hydraulic type or mechanical
The stop type operated directly
commonly used by the brake pedal,
being more the latte
.e msed to give an indication to the dver of other vehicle
stop light is us
is
The vehicle's speed and stop if required.
coming from the
back so that they
down his may slow

Tail ights are used to show red at the rear of the hicle. Tail light are kept
ON all the time when car
so that the other vehicles coming behind it anre able to see it
is nunning at night

Indicator Light

Direction indicator

DDrawa abelled sketchofndicator MSBTE:W1

igtt circuit Explaintits working
(W-11) W11)
Now in modem vehicles flasher type
direction indicator is used. These indicators
vehicle. In both circuit second are provided at front and rear of
filament of bulb or separate indicator lamp is used. These are independent
amp. from stop tail

When the brakes are being applied at same time direction indicators
are in operation with relay unit used. The
unit used in this
circuit is explained. flasher

Main amature- Setael core fSecondany

and contacts and coil amature and
pilot contacds

Ballast
resistor

Actuating wire-

To lamps P
From battery To pilot lamp
naSwitch
r relay

Fig.5.7.4: lasher unit circuit

Techneuledge
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 Automobile Electrical and Electronics:Systemm
Engineering (MSBTE Sem-V) 5-34 s
Automobile
Waming
light
Flasher
untt

LH.Front lamp
L BD
Light green
Green&
jbrawn
R.H.Front lamp

Green&
Green&
white
red

R.HRear kamp
LHRear lamp
indicator
Fig.5.7.5: Four lamp direction
will flow through the main armature
construction of a flasher unit is shown in Fig. 5.7.5. The current
An intemal through the flasher lamp filaments to.
resistors and the coil wound on the central core as well as
actuating wire, ballast left or the right.
switch is moved either to the
the earth, when the direction indicator
limitations but are kept to a low value by the ballast
lamps are not allowed to get illuminated due to the current
The
resistor. the suspended spring
armature to move inwards the core under
actuating wire will expand in length causing the lamp illuminated as
.The current. Therefore, when the contacts are
closed and
tension duc to heating.influence. of the
flashing
4. Turn Signal Light
automobile
vehicles and pedestrians in which direction the
purpose of the tum signal lights is to indicate the other
.The usually operated by a lever located under the steering
wheel.
is going to be turned. These lights are
that is automatically switched off when the
steering whecl is retumed to
Most of them are of the self-cancelling type
straight-ahead position.
is shown in Fig. 5.7.6. This was operated by a wire or
by clectromagnet.
The semaphore type used in the past
light blinks is mostly used at present. This type is
usually made to serve also as
The flasher type turn signal in which the
parking light.
times a minute.
when in operation, flashes on-and-off from 50 120
to
The flasher light
flasher lights are
An indicator light on the instrument or
clicking sound is normally provided to wan the driver that the
operating.
Bulb
Point-

Am

Switch
Magnet

Battery-

Fig. 5.7.6:Semaphore turn signal

Kaeuledge
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 (MSBTE_Sem-V) 5-35
Engineening Automobile
udomobile Electrical:
Electronics
Light System
Backup illuminating
indrcation or are
thescC in back of car when transmission
Thesegive is shifted into
reverse direction.
Impol nce
of Cable Color Used for Wiring
the Lighting
5.15 MSETE: S14.WSLHSA5AWEE System:
Ma6:SA7,WS17/
colour.codes
arious colour
various
ic
codes uged n wiring system. State its necacdh
S-18W518:S-19
aEnlist the
Codes usedin wiring svsterm
any four colour automobile. S-14)
Slate
Slate A

colour coding used automobile wirng system.

in (W-14)

ucodes colour.codes of wires

use
of
Wires used jn autornoDe
diferent winng system. S-15)
Wite 04-15,W-16,s-17,S18,
any four.colour codes usedin wiring system of automobile W-18, S19)
W.
W-17)
rrent to tthe various electncal units of an automobile
curent
To camry the and for identification
of cable, different colour
codes are used.
main colors namely, brown, yellow, white.
There are seven gren, blue, red and black. Their
applications being
has own as
lows and each color its identilication in the wiring of lighting
system.
Colour used for wiring
the lighting system

1. Brown

2 YelloW

3. White

4. Green and Light Green

Red

7.Black

Fig.C5.7
Brown

'tis denoted by capital letter B and small as Br,

r
Used for the
battery and generator circuit.
It goes rom the
battery or motor starter switch to the ammeter or control box and with compensated voltage control,
feeds hel box terminal.
ugnting and ignition switches, also the radio set, when fitted from the control
auxiliaries
1 USed for leads from the motor starter switch to the electric clock, inspection sockets and battery
are fed the electic horn, cigarctte lighter, interior lights etc.
Which
Yellow

Itis denotedby
capital letter Y.
Used for
the dynamo circuit.
control box terminal and the ignition waming light.
LOm the dynamo terminal to the corresponding TechMaledgi
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Automobile Engineering (MSBTE_Sem-VI) 5-36 Automobile ElectricalandElectronics
System

White

.Itis denoed by capital letter W.

Uscd for the ignition cireuit and all electrical components that may be used while the igition is switched on btt do
&
not
require a fuse.

Eg. the electrical petrol pump, starter solenoid switch etc.

Green and Light Green

Itis denoted by capital leter G and Light Green by lg

Uscd for the auxiliary circuits fed through the ignition switch and
protected by the ignition autiliaries fuse, e
o he .
brake stop lamp, direction indicators, windscroen wiper etc.

Blue

Itis denoted by capital letter L

.
Used for the head lamp circuits and fed from the terminal on the lighting switch.

Eg.lighting switch to head lamp.

Red

Itis denoted by capital letter R.

Used for the side and tail lamp circuits and fed from the teminal on the lighting switch.

Included in circuits are fog lamps, panel lights and other lamps which are required only when the side lamps are in use

Black

Itis denoted by capital letter B.

Used for earthed circuit.

If, however a component is not earthed, a cable must be taken to a good carthing point on the chassis.

Sr No Code
Cólour Colour unction
01 Brown BR Battery circuit

02 Yellow Y Generation circuit

03 White W gnition circuit

04 Green G Auxiliary circuit

05 Blue BL Head lamp circuit

06 Red Side lamp and tail lamp

5.7.6 Wiring Harness MSBTE:S-14, W-14, W-17

pain ine ypical wiring diagram of automobile with

EXpláin Wire
harmess
nea
19 W-14

Describe wire haness: W-17

The group of wires are wrapped together to form wiring hamess. Most vehicles have several wiring harness whicn
throughout the body. Wiring harnesses connects the light with the battery and alternator. So the electrical system ol a
(wiring harness) has two main functions.

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itl

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 (MSBTE Sem-VI
mobile Engineering
5-37
electrical
clectrical eenergy to start Automobile
Electrical
supP!y
aly and operatc and ectronics
tmust the enginc.
System
power operate
) proVIdethe the ights, instrument
tmust andother
electrical accessories.
Wiring trough s lo antena
Relay module

lamp-outag
module
44 way conneclor
Radio
Instrument
panel cluster

BlOwer
motor

feed
To booy Grominet
To vacumAU
controler module(ATC)
To windshiekd washer
pump motor
4-way
To belower motor Connector
resistor block Diagnostic
To washer fiuid Connecior
To airbag
level sensor
dignostic module
To end erhood lamp
To keylght and
To multi function- key-inignition switch
Switch
To speed
controlgnition Switch

Fig.5.7.7: Wiring harness and connectors behind the instrument

panel

Windshield
Wiper motor Starter
Windshield relay
Acdutch
Grommets Cutout relay
wiper motor
connector
Low washer Fusible Radiator
fuid washer inks fan rele
Fue-pump
Washer
pump water relay

Engine
controler
Washer
reservoirK
Security alamm
hood ajar switch

Braka waming
Head lamp
lamp swilcn
ground
Map sensor Master
Cylinder

compartment
in the engine
Fig. 5.7.8:The wiring harness

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 Automobile Electrical
(MSBTE_Sem-VI) 5-38 and Electronie
Engineering Siystem
Automobile
gauges:
Differenttypes of
5.8
5.8.1 Gauges:
Types of Gauges

1. Fuel Indicator (Fuel Gauge

2.Oil Pressure Gauge

3. Water Temperature Gauge

Fig. C5.8:Types of Gauges

Gauge)
1. Fuel Indicator (Fuel
remaining in the fuel tank.
the amount of fuel
The fuel gauge indicates
and the cross coil type.
gauge, the bimetal resistance type
There are two type of fuel
is used in mošt recent
automobile vehicle.
gauge (non return type)
The cross-coil type fuel

A.
Cross-Coil Type Fuel Level Gauge:
MSBTE W-15;W-18

W-15, W-18)
gauge
Sketch and explain working ot uerievel
the fuel tank to a driver. It located on dash
is
indication about the amount of fuel remaining in
The fuel gauge gives the
resistance type and the cross coil type (A.C. electrical
type of fuel gauge, the bimetal
board in front of driver. There are two
return type) is used in most recent automobie
with balanced coil type). The cross-coil type fucl gauge (non
fuel gauge
two coils which are aranged at 90 with te
turned to ON, a current flows through the
vehicle. When the ignition sitch is
which pointer attached
magnetic ficld produce acs on armature to
armature and pointer assembly. A
Ignilion
SWitch Battery

Rneosta

Tank
unit
Amature

Pole prec8

Fig.5.8.1:Cross coil type

empy
flows tnroug
When the fucl level is high and float is up, the resistance in the tank unit is high, the current
ofthe d
col A and aso full trough B. thus the armature is pul to the right so that a pointer indicates to ngn su CuTent
gauge. When the fuel level is low or empty, float moves down and the resistance in the tank unit is dectee wea
metic field
1lows through an coil A passes through the tank unit. Due to less current flow through the coil A 15
and the armature pulled to the left.
Hence pointer moves to left (A).

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 (MSETE_Sem-V)
Engineering 5-39
En Automobile Electrical
AUIDUNOe type
&BITetaesista
Imeta-resistance and Electronics System
Voltage
regulator
Fuel recever gauge Fuel level
sender
Slidingresistor)

ww
gniton
switch Heat
Wire

Battery

Water temperature
receiver gauge

Watertemperatire
(Ihermistor)

Fig.5.8.2: Bimetal Resistancetype

bimetalelement
d
is used iin the receiver gauge and a float type sliding variable resistor
A
is used in the sender
gauge
ignition
dn scwitch is turned to ON, a current flows through the voltage regulator
Whcn the and heat wire in the receiver
grounded through the
sliding resistor in the ender.
and is
the receiver generates heat when he cuTent flows, bending the bimetal in proportion
in in the
beat wire to the strength of
The result, the pointer connected to the bimetal deflects.
the
urent. As a
level is high, the resistanceof the resistor is low, so a greater amount of current flows.
When the fue

oreater amount
Therefore, a greater
amount of heat is generated in the heat wire, so the bimetal element warps a lot, causing the pointer
further toward the
"FULL" side.
o mOve
the fuel level is low, the
resistance of the sliding resistor becomes great, so only a litle curent flows.
When
, Therefore, the bimetal element warps only a small amount and the pointer moves only a small distance.

Siding resistor

Thermistor
(For waming lamp)

Float anm-

LFloat

levelsender
Fig. 5.8.3:Fuel
fuel, a sender body
with the surface of the
The
loaty moves up and down
consists of a float, which
ih abuilt-inDTEsistor
sliding which connects
m,
them.
resistor and a varying the resistance.
Autbe
the resistor changes,
loat the contact sliding on
e position of Techfavuledgë

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 Automobile Electrical
Sem-VI) 5-40 and Electronics
Engineering(MSBTE
Automobile Systein
set in ether the upper portion or lower portion
rtion of
of the
float position for measuremenl is tank.
The reference
low reference position is more precise when fuel is low.
Since the type using a
having an cnlarged
display function.
gauge
It is used in

Total resistanc

Output teminal

Slides

Output

Fig.5.8.4

2. Oil Pressure Gauge

These are of mechanical or electrical type.

.The mechanical pressure gauge is in the form of Bourden pressure gauge on the dash board
O pressure
Binea receiver gauga
eemet
Hegt wieye

Bimeta Headwire
element

Point
gniton
SWlcn

Diaphragm

Batey
ll$ende
pressure

Fig.5.8.5:Abimetal-bimetal type gauge is used for the oll pressure gauge

For the engine bearing, it is connected by a pipe to the oil feed line and read the actual pressure.

.The gauge consist of curved tube which is connected to oil feed line.

.While other end is joined with gauge needle through pipe line.

This gauge works on the principle that curved tube get straighten
up of the tube causes the rotation of the gauge Der e.
The electrical type of oil pressure gauge consist
of a flexible diaphragm rning
switch linked to the oil fced line and
lamp in improve the performance and easy detection
of a problem in the lubricating system.
A bimetallic type oil pressure gauge is used.

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 (MSBTESem. 5-41
Engihes
Engineenng Auto
mobile
ALTOmoDe cal andElectronics
System
pressure
alonressurelow
low/No oll
Dupressure Ol pressure recerver
gauge

1gnition
SWitch

Battery
w Oi pressure
sender

No ol pressure

Fig.5.8.6: No oil pressure

binetal element io the. sender is provided with contact points which moves the needle of the gange in aærordance
The
with the curent flowing in the receiver heat wire.

When the oil pressure is 0, the points are open and no current ilows when the ignition switch is tumed on. Therefore,
thepointer remains at O.
When there islow oil pressure, the diaphragm pushes he point, establishing a light. contact A cument then flows
through theheat wires in the receiver and sender.
to a sight
Because the point contact pressure is low, the points are opened by warping of the bimelaf element due
CUITCnt:

even for a very short time, the temperature of the bimetal

Since the scnder side points are opened by a current flowing
bimetal element is smal. As a esult, the pointer
Cent in the receiver gauge does not rise, so the warping of the
defiection is slight.

Ol pressure high

Asthe pressure rises, the diaphragm pushes the points strongly, raising the bimetal element
upward
the bimetal element bends
So thecurrent flow for a long time because the
points are not
opened unless
LUst
enough to counteract
this.
the bimetal element in
Since the sender side
points, the temperature of
thecurer
I ows for a long time until opening of deflects greatly.
warpage. Asa result, the pointer
ECIVer rises, increasing its amount of the sender.
the bimetal element in
Lherefore, proportion to the warpage of
the bimetal element in the receiver
rece warps in
t

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 Automobile Electrical and Electronine
Sem-VI) 5-42 Syslem
Engineering(MSBTE recaiver gauga
Automobile Oil pressure

Igniion
Switch

ww Oil pressure
sender
Bater

Oll pressure

Fig.5.8.7:High ol pressure

3. Water Temperature Gauge

*fgauge

onišion swrich
or usa

Fig. 5.8.8:Electrical water temperature gauge

temperatue
economical and important one. If gives indication of
Itis an optional accessory provided on engine but very
ofcooling water to the drives at all time.
help the motorist to avert serious consequences do sticking up of the
thermostat causing its clouser.
It
temperature. From this gauge the dve
This will stop the circulation of water and results in very high rise in engine
accessory against engine.overheatmg
wil be able to stop the vehicle and the engine at once. Sa it is an a safeguard
protect from damage.

The two type of water gauge used in modem yehicles.

() Amechanical type (2) The electrical type

The mechanical type is known as.capillary tube is connected by a capillay abe to the çiement or a small buln
diator
A thermostat is connected to the engine cylinder head or block, thermostat housing, radíiator header tank,
1op

hose or the water pump.

olled by
By capillary tube bulb is connected to the Bourdan type pressure gange an the facia. The gauge reading is Cn
the increase of pressure in the tube due to vaporization liquid by engine heat.
of
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 Electronics System
Engineering
(MSBTE_Sem-V) 5-43 Automobile Electrical and
onobile
of the curved
cu or Bourdon tube due to increase pressure, the pointer ofgauge is moved to indicat
raightening outtof
Hilhs rahure.
lemperathu
higher
the gauge in the clectrical type which has a similar builb unit or element mark of material whos
tvpe of
sistance
resistance decreasc
temperature increases. Inside the dash board unit, the element is connected to cou
decTease with tem
elctrical
5,.8.9.
shownin
Fig
clement is
meler c aining coil is provided on the facia or the dash board. At a specifc place, the gauge
moving iron
ADn the cooling water line. The curent passing through the coil is controlled the meter rcading
A

ftedinte element the coil.

decrease clement resistance (caused by cooling water temp. rise) more Curent will flow through
of
With the
cause
1 on increased pull of the coil on the armature carrying the indicator pull of the coil on the armature

the indicator which moves to indicates the higher temperature of cooling water directly in degree centigradeE

Capilary rElement

Fig.5.8.9:Baurdon tube

$82 Wind
ScreenWiper:

A
wisdscrecn wiper or windshield wiper
is a device used to remove rain and debris from a windscreen or windshield:
This
is helpfal duing wet atmosphere, rain or snow. Almost all motor vehicles are equipped with such wipers, which
are usually a legal requirement.
, Mast automobiles use two synchronized radial type arms, while many commercial vehicles use one or more pantograph

Construction The modern. car are provided with effective high speed wind wipers operated by, electric
amd Working:

curent (Batiery) or by
vacuum operated unit. A wiper generally consists of an arm, pivoting at one end and with a long
nbber blade attached to the other. The blade is swung back and forth over the glass, pushing water from its surface. The
sped is normally adjustable, witb several cantinugas speeds and often one or mare inicmitteat setings

I consists, of small motor, worm gear and worm wheel assembly and flexible cable. it is fitted in bonnet and easily
zcessible whenever required. The motor provide drive thirough reduction gear. It provides reciprocating action. This
mciprocating action is converted into angular displacement of wiper.

Won
Capss head
rCasing
Abng

Cabla

Whel

(b)
(a)
Fig. 5.8.10 Windscreen wiper
Atelia
formeda through two wheel boxes at the
per endnad around the cable constitutes rack and whecl gear box. The cable passes
ofunit. The worm arm spindle caried in bearings-

iven
Palo
.
pantograph
by the wheel rotating back and forth in the wheel box due ta pulling
dtomobiles use two synchronized radial type arms, while many commercial
of cable rack backward. and
vehicles use one or more
arms.

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 Automobilte Electrical and Electronics stem
Automobile Engineering (MSBTE Sem-VI) 5-44

5.8.3 Automotive Sensors and Actuator:

of electronics
systems to improve vehicle performance,
perf
manufacturers are continuously increasing the use
Aulomotive
Safety. passenger comfor. heip optimize vehicle
ers help vehicie perfor
with automotive
control computers perfomance while
actuators integrated
Sensors and
improving reliability and durability.

Sensors
sensors are explain below:
The vaious type of
Types of Sensor

1) Inductive sensors

2) Hall Effect Sensors

3) Light sensar

4) Resistive Sensors

5) Voltage-Generating Sensors

6) Switch Sensors

7) Temperature sensor

8) Pressure Sensor (MAP)

9)Oxyger Sensor

10) Crankshaft Position

Sensor

11) Throtlle Positijon

Sensor

Fig.C5.9:Types of
1) Inductive sensors
sensors

Controler cabinet

Vehicde LEdHn
rdoed ducive wire
Lead-in i anics ut
UTenis: ire bo) cable O
T 9nenwOk Standard target
Clatbr, and
Targat
Renforcrg
see mesh4 res
Proximity swich
pulse Direction Active face
OUtput
of motion

Fig.5.8.11

ectloeuled
Pplicatiu

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 Engineenng(MSBTE Sen ) Electronics SystE
omobile 5-45 AUtomobile Electrical and
used to
sor is also callcd as an inductive proximity sensor is sensor that is
Inductiv a type clectronic proimy
ohjects without touching them.
tion of metal
position The sensing range of an inductive switch is dep
ketectthe detected.
metaltobe aluminum ard
Dpeof steel, such as
such as iron and
metals, longer sensing while nonferous metals,
ramge,

,ao oce the sensing range by up to 60 percnt.

surroundi
pincipleis based on a coil and a high frequency oscllator that creates a field in the closed This
working
The oscillation amplitud
The presence of metal in the operating area causes to change in the
Surface. seisor
theidentiffed by threshold circuit which changes thie output of the sensor. The operating distne
e
depend on
the coil size as
well as target shape, size and material.
magne
sensors for operation depends on three things that are a coil (winding), A
inciple of inductive
princ an induction
coil
magnet and
The n. The crankshaft sénsor measures the engine speed. It consists of a permanent that
collapses generating a curen
irun core: When the electric curent is generates a magnetic field, hich changes
with a soft inductance of the (coil) loop
toward zero from iits initial
transfer when the input electricity ceases. The presence
falls other materials the
terial
material inside it and since metals are much miore effective inductors than
ccording to the i which can.
This change detected by sensing circuit,
he curent
increases the flowing throngh the loop. ca be
of metal detected
denal to some
other device whenever metal is harsh
especially in
widely used to measure position or speed (anti-lock brake system),
Inductive sensor are
environments

Effect Sensors
Hall sensors zare
moving objects. Hall
for the purpose of detecting the position of
Sensors Hall sensoTS are often used maïntenance free: "They
Hall this they do not wear out thrvugh contact and hence these are
comtactless operation because of
fluctuations and vibration.
unaffected by temperature am
re carrying. semiconductor,
effect. When a magnetic field acts on a curent
on Hall semiconductor
Hall sensor working is based current strength through the
produced at its end faces. If the
will be
electrical voltage (Hall voltage) the magnetic field
strength the generated voltage will only depend on the strength of
remains constant, the of for
thie Hail voltage will also change:
Whea uscd as position sensdirs
changes,
the magnetic field slow or
f the sttengtk of sensors particular advantage vwhen the change in the
magnetic field is comparatively
magnetic parts, Hall are of induction voltage. Hall sensors ae used in a
as the sensor would supply no significant
zera. Ia these cases, a coil used
in the seat belt buckle,
door closing system.
wide variety of Applications,

3Lightsensor form a trigger device for thie SCR, providing

lamps to iluminate at sunset and turm off
'Tiais device allows oneor more
hits, the photo resistor
assumes a very law resistance value,
set. When the light
short pulse frequency. Pulse duration
is
resistmce valne becomes very high thus
circait operation. When is in the dark, its
almost shorting and preventing

emabling circuit operation. developed

sensor. It makes usc of tnc photovoftaic voltage
an ordinary LED as a light
Tis circuit shows how to use photodiodes and come with a built-in filter, which is
exposed light. LEDs are cheaper than
aCTOSs the LED when
it is to
discrimination.photo-voltage of a Ted LED (its band gap voltage) is
ihe
when the application involves colour
300M.2 m dayhght, Tising to infinity in darkness. A
aSeful

source impedance of this voitage abouti5

9ypically about 2V. The high impedance signal.
amplify and buffer this extremely
DFET iput op amp is used to

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 Automobile Engineering (MSBTE Sem-VI) Automobile Electrical and EHectronics System
5-46
BV

-o Output

470k

LEDIS0w V

33k
-00V

Fig.5.8.12
4) Resistive Sensors

Resistve sensors, such as the potentioimeter, have tiree terminals: power input, grounding temina, and variahle
voltage output. These mechanical devices have varicd nesistance thut can be changed through movable contact with its

ixCd esistor. Output from the sensor varies depending on whether the movable cotact is near the resisto's supply end
or ground end. Thermistors are also variable resistors, athaugh the resistance of the sensoT varies with temperature

Variable resistors is a throtle psition sensor in operates a continuously variable resistor to generates an analog signals.

Variable rusistor changes thè sensor's intermal resistarice with the position of the thiotle. The voltage produce by the
sensor is also continuously variable, it is an analog, signals. The signals can be of any value from 0 (Zero) through
battery voltage. A Fuel gauge sender is another device that uses variable resistor to generate an analog signal.

5) Votage-Generating Sensors
Voltage-genèrating šensons, such as piezo electrics, generate electricity by pressure with types of crystals like qauartz As
the crystal fiexes or vibrates, AC voliage is pioduced, Knock sensors uilize this technology by sending a signa' to
a
automobile's on-board computer that engine kiock-is happening, The signal is generated through crysta vibration
within the sensor, which is caused by cylinder block vibration. The computer,
in tum, reduces the ignition iming to stop
the engine knock.
6) Switch Sensors

Switch sensors are composed of a set of contacts that open when close
to a magnet. A reed switch is a common example
of a switch sensar amd is most commonily used as a speed or positión sensor. As
a speed sensor, a magnet is attached to
the speedometer cable and spins aong with it. Each time one of the magnet's poles passes the reed switch, opens and
it
then closes. How fast the magnet passes allows the sensor to read the vehicle's
speed.
7Temparaturesensor
When two dissimilar metals are joined together, the thermocouple junction
is formed. Among the two junctions used,
one of the junctions is kept at a constant known temperaure where as the
other at the temperature to be measured. E
70% platimum& 306 thodium alloy knowIT as B Type
and has a range of 0 15000C.
The electrical resistance of the
sensor decreases as the temperature increases.

Used for measuring Exhaust Gas and turbocharger temperatures in a vehicle. The temperature
of coolants, fuel and ar.
These are Installation Engine block, coolant circuit, air-intake tract.

Pressure Sensor (MAP):

Tt supplies engine load information to the engine control module. The engine control module uses this information to

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s Atormobile Engineering ASBTE Sem-VI)
5-47
delivery. In addition, Autormobile Electrical and Electronics System
calculate fuel some engine
cal
imins ke manifold vacuum vanes control syste
with engine
ystems will use
MAP sensor information to calculate spark
manifoi um is high.When the engineisaccclerating
speed and load.
When the vehicle
ehicle is at idle or decclerating, intake
1
or under aheavy
Intakemanifold vacuum is a direct dicator load,i
load, intake manifold vacuum drops.
rof the amount
voltage signal orf
frequency (some
vehicles), of load placed
to the control an engine. The MAP sensor sends a
the intake manifold. module that coresponds with the level vacuum present i
Tesponds vwith of
Oxygen Sensor
9)

The OXygen sensor produces a voltage signal

based on the
signa is used by the tontrol mod to amount of oygen in the
provide cirl exhaust of the engine.
fucl míxture information
xygen sensor is placedinthe exhaist.stream m ffor fuel delivery and emission control The
of the engine.
yoltage signal based or ne When heated,iit acts like small battery
ratio of oxygen in the exhaust a to produce a
system and reference
sampled from the atmosphere ait contained inside the sensor t

.A high exhaust oxygCn content

Would indicate lean
exhaust and result
Low oxygen content indicates in low voltage output from the oxygen seD
a ich exhaust and would
result in a high vóltage output fromthe sensor.
module monitors this voltage output 1he con
to constantly tailor fuel
delivery to maintain a precise air/fuel ratio
ratio is needed for efficient operation of the of 14.7-1.
catalytic comverter.
A property workäng oxygen sensor will produce varying
a voltage signal from below 200mv to above 800mv, as the
fuel system works to maintain airfuel ratio. The
average voitage reading from the oxygen sensor
should be around
450mv. Oxygen sensor Tesponse tim from rich lean,
to should be less than' 100 milli-seconds. An improperly working
sensor can affect éngine performance and emission Tevels.
.
A false, low voltage output from he sensor, can result inl excess
fuer being delivered to the engine amd' affect foe
milcage, drive ability and vehicle emissions. Severe cases can cause catalytic converter damage from excess fuel
in the
exhaust system. An oxygen sensor with slow TEsponse time can affect emissions and fuel economy as well.

Oxygen sensors can bé contaminated by silicone, caning a high but fase voltage signal and tesulting in por engine
performance from improper fuel delivery. Countless big ticket auto .repair jobs related to engine performance can be
necessary.
avoided by simply inspecting this senšor and roplacing if
Zirconia sersor
rHigh-pressure
Seal
Exhaust gas-

Sensor shield-

tsideair

-Housing

Interior platnum
elecrode
(for outside air)

Exhaust manifod

Exterior platinum
electrode

for exhaust
Fig. 5.8.13
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 System
Automobile Electrical and Electronics
Automobile Engineering (MSBTE SemV) 5-48

10) Crankshaft Position Sensor

speed and cylinder position. The control
control module to calculate engine
The crankshaft position is used by the sensor is a 5ignal generator that
ignition control. The typical CKP
module uses this infomation for fucl delivery and
produces an AC voltage signal based on engine speed. either
on the crankshaft. The toothed wheel is
relation to a toothed wheel, mounted
The CRP sensor is placod in close toothed wheel 15 rotated past the
front or rear of the crankshaft. When the
Cast into the crankshaft or mounted at the

CKP sensor, an AC voltage is generated by the sensor.

the engine. The control modale
wheel corespond with the
cylinder position of
strategically placed in the tothed
Gaps cylinder poSition accordingly.
change sensor output and is able to calculate
in CKP
mCks up the BAps as a momentary

Fig. 5.8.14

11) Throttle Position Sensor

movement. The control
changes value based on.throttle
Throttle Position Sensar
(TPS) is avariable resistor that
compensate for throtle opening. Vehicles equiped
The
module uses information from this sensor to adjust fuel delivery to
transmission shifting as weli.
the TPS to control
electronically shifted transmissions use information from
with
an intermal variable resistor to output a
thie control module and changed by
voltage is supplied to the TPS by
Reference typicl TPS will have a high
resistance at closed throttle, that will steadily
throttle position. The
signal relative to
decrease as the throttle is opened. reference
voltage output at idle and a voltage
output that reaches maximum
signal produced by the TPS will be low controf module is able to
The volts. By monitoring changes in the TPS sigmal voltage, the
voltage at ful throttle, near 4.5
calculate fuel delivery accordingly.
determine throttle angle and

Actuators used in
digital actuators
that sets a system into automatic motion. Stepper motors are
mechanical device
An actuator is a computer to set comect idle speed and control the idle air
bypass. Solenoids, as wih
automobiles to allow the on-board and the
to the vehicle's battery
actuators with one teminal of the solenoid attached
stepper motors, function as digital related to emissions and
When given power, the solenoid extends a.plunger to control functions
on-board computer.
fuel-injection.
describe a control mechanism.
Actuator is a general term to unit with the proces
open-loop or closed-loop control system which connects the electronic
An actuator is part of an
converted to me
consists of a transformer and afinal-control efement. Each positioning signals are
The actuator
output.
used in control loops in an automobile.
A wide variety of actuators are

Some of the actuators are

Solenoids Actuators 2) DC Motors

1)

Stepper motors 4) Piezoelectric Actuators

3)

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 Engineer (MSBTE Sem-VI)
ocbile Engineeing
Automobile 5-49
Automobile Electrical and Electronics System
Actuators
Solen ld
principle
uinciple of
o faradays
work on the
e law of clectromagnetic
This induction.
a coil of wire which
nid is
v get wound on the
long cylinder
core called anmature is drawn that when carryinga
,AmOvable into fixed
coil when pulled-in
ng a current resembles a bar magnet
so solenoic etcrgized hence it is used the coil then a current flows in the circuíit
to convert electrical
and energy into mechanical energ
ment of the core
movement ore compresses spring.
mally, the
Norma a When power-off,
POSTton
the armat
mature returms back to its normal

The
.
strokeeooff the armature varies from fraction of
mmto
several mm depending
on application.
are two main categories of solenoids:
There. Rotary solenoid - rota
the armature. rotary motion of the armature
incar motion of
and Linear solenoid-
Application:Fucl injector

DC Motors

D.emanent magnet motors are commonly

Pe used in automobiles
as they are versatile
The rotarymotion speed (RPM) of the motor which is
usually high is suitably modified
in tarque) or other mechaisms to get the desired rotary
through gearing down (increase
or linear motion.
Aplications such as:

power electric stering,

Windscreen and head light washers & wipers.
3) Power windows and mirrors.

4) Fuel pumps

5) Head light ifs..

6) Electronic Parking Brake (EPB)

3 Stepper Motors
Stepping motors are divided into two types:.
1) Permanent magnet Type : In this motors consist
of two independent windings, with or without
tapped windings are used in uni polar pemanent magnet
center taps. Center-
motors.
2) Variable reluctance Type: In this motors consist
of three or more independent windings, with a
common retum
winding.

For both permanent magnet and variable reluctánce stepping

motors, if just one winding of the motor is
energized, the
rotar (under no load) will snap
to a fixed angle and then hold that angle until the torque exceeds the holding
torque of
the motor, at which point, the rotor will turn, trying to hold at cach successive
equilibrium point.
They do not have high starting torque.
Applications

1. Idle speed
air by-pass
2 Electronic Throttle control
3. Speedometer
display drives

4 Adaptive Front-lighting
(AFS) system,

Technautedgë
catleas

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 Automobile Electrical and Electronics System
Automobile Engineering (MSBTE Sem-V) 5-50
4) Piezoelectric Actuators

A piezoelectric actuator enables response times of just a few Tenth of a

millisecond.

icomsists of many crystáil layers that expand by a few hundredths of millimetets when vollage is applied.
.One of the automotive applications of the Piczoclectric actuators is in Diesel engine fuel injection Systems.

Revleiw Questlons

Q.1 Why it is necessary to charge automobile battery2

02 Explain construction and working of battery.

a.3 Define and explain battery rating and batfery capaity,

04 Explain sipecific gravity test of battery.

Q.5 Explain the cormponent of alternator with their functions.

Q5 Explain woring of attemator with sketch.

0.7 Explain working of staring motor.

a8 Explain layout ofslarting system.

a9 Draw the witring circuit of starting motor.

a.10 Explain construction and working of Bendix driva.

Q11 Enlist the varñious types of sensor úsed in vehicle.

Q.12 Explain battery ignition.system with sketch.

Q.13 Explain electronic ignition system with sketch.

Q.14 Compare battery and magneto-ignition system.

Q.15 Compare battery and electronic ignition system.

Q.16 Explain lighting diagram of an autornobile forfoiur

wheeler.
Q.17 State any four type of actuator.

Q.18 State the applications of D.C. motor used in vëhicde.

Q.19 Explain the colour code used in automobile

wire hamessing.
Q.20 Statethe functions of battery.

0.21 Statethe function and symbol

of tollcwing

(a) Resistor (b) Diode (o) Capacitor

(d) Transistor

O00

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 Sem-VI)
able ofCoten
Automobile Engineering (MSBTE_

6.6 Claintor Compensation

UNIT VI w
******'*****"********tofi

6.7 Tratfic sign .. ********

re
Chapter 6: Motor Vehicle Act, Road Safety
6-1 to 6-29 6.7.1 Central Motor Veicle Rules..
and Garage Practices
6.8 Classification and Definition of Vehicles..
****is
Syllebus:
6.9 Enforcement of Emission Norms.
Salient
6.1 Introduction and Objectives af Motor Vehicle Act:
Features of M. V. Act 1988 and Central Motor Vehicle Rules .10 Types and significance of Traffic Signs.
Important
1989. Types and Signifticance of Traffic Signs, 6.11 ImportantTransport Tem...
****************
Transport Temns (Definitions) in M. V. Act (Motor Vehicle, ******ss

Motor Cyde, HGV, MGV, LGV, Fublic Service Vehicle, 6.12 Organization Structure of Motor
Transport Vehice, Driver, Passenger, Accident). Vehicle (ATO) Department.

62 Organizaion Structure of Motor Vehicle (RTO) Department, 6.12.1 Regional Transport Office (ATO)..
Dutes and Responsibities of RTO, AMV. Duties and Responsibiliiy of RTO and AMy.
o.12.2
6.3 Passenger Comfort and Safety: Function and 6.13 Passenger Comfort and Safety..
requirements af Passenger Safety System. Features of Ai 6
Bags, Seat Belts, Collapsible Steering Column. 6.14 Automobile Maintenance System.
62
6.4 Automobile Maintenance Systems: Significar of 6.14.1 Significance of Garage, Workshop,
Garage, Workshop, Service Station, Dealership. Service station..

6.5 Types of Maintenance, Need and importance of Reccrd .15 ype of Maintenarnce.. 62
Keeping, List of Records to be kept in Service Stations. 6.15.1 NNeed and importance of Record Keeping... ..6-2
6.6 Site selection and amenitiesfacilities required to set up your 6.15.2 List or record to be kept in service station.
own Garage/Service Station, Role and Responsibilities

Service Manager, Service Supervisor, Customer 6.16 Site Selection and Facilities Requirad
Care
Manager in Service Stations. tor Garage.ar Service Station.. 6-2

6.1 6.16.1 Role And Respansibilites of Service

Motor Vehicle Acts and its Salient Features. . 5-1
Manager in service station... 6-2
62 Ragistration of Motor
Vehicles. 6-2
*
6.16.2 Role And Responsibilities of Service
6.3 Driving License... 6-4 Supervisor in servicestation. 6
6.4 Contral of Traffic
..646.16.3 Role and Responsibilities of Customer
6.5 nsurance against Third Party . 6-5
CarsManagerin service stationi... 6-2

DO
 Motor Vehicle
((6) Safety Act, Road
S
and Garage
Unit- VI Practices
Syllabus:

6.1 oduction and bjectives

of Motor Vehicle
Vehicle Rules11989.Types Act.
andSignificance Salient Features
Act (Motor Vehicle, Motor olTraffic of M. V. Act 1988 and Central
Cycle, HGV, Signs, Important Motor
Passenger, Accident). MGV, T
7 ransportTerms
(Definitions) in M.V.
LGV, Public
Senice Vehicle,
6.2 rganization Structure
Organization Transport Vehicle, Driver,
of MotorVehicle
(RTO) Department,
6.3 Passenger Comfort a
and Safety: Function Duties and Responsiblies
of RTO, AIMV.
Bags, Seat Bets, Collapsible and requirements
Steering Column. of Passenger
Automobile ger Safety System. Features
6.4 Maintenance of Air
Systems: Significance
65 Types of Maintenance, of Garage,
Need andimportance Workshop,Service
Station, Dealershup
of Record
86 Site selection and amenities/failities
Keeping, List
of Records to
Responsibilties required to be kept in Service Stations.
of ServiceManager, set up your. own
ServiceSupervisor, Garage/Service
Station, Role ano
6.1 Motor Vehicle Acts Customer
CareManager in SenviceStations.
and its Salient Features
Itis an Actto'consolidate'
and amend
1939 is applicable the lawsrelating to motor
and extends to whole vehícle. This
Act known as the
whenit wassuper of India. This Act enacted in 1939 Motor Vehiclé
sealed by motorvehicle had been amended Act of
act 1988 according from time to time until
Thenew motor
vehicle act 1988 effective totherequirements and 1988
necesities ofthe
amended uipto we.f. 1 july 1989 has replaced roads and vehicles.
2006 has nine chapters, the Motor Vehicle Act
135 sections and twelve of 1939 . This
the various
topics under thie following
schedules. The
ten chapters having Act as
hieadings: 135 sections
in all explain
Chapter
Preliminary
ChapterI1
Licensing of driversof motor vehicle
Chapter
Il Licensingof conductors of
stage carriages
ChapterIV
Registation of motor vehicle
Chapter V
Control oftransport vehicles
Chapter V
Special provisions relating to state transport underiaking
napter VII Construction, equipment and inaintenance of motor vehicle
Chapter
VIll- Control oftraffic
Chapter
1X Motor vehicle temporaily leaving or visiting lnlia
BaplerX Liability without fault in certain cases.
pler XI Insurance of motor vehicfe against third party nsks
Chapter
XII Claims Tribunals
Chapter
XII Offences, penaltúes and procedure
Chapter XIV
Miscellaneous.

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 Automobile Engineering (MSBTE Sem)_ 6-2 Motor Vehicle Act, Road Safety and Garage Practices

The important provision of the motor vehicle Act 1988 are explain briefly:

6.2 Registration of Motor Vehicles

(a) Necessity for registration

No person shall drive aniy motor vehicle and no owner ofa motor vehicle shall cause or permit the vehicle to drive in
any public place or in any other place for the purpose of carrying passengers or goods unless the vehicle is registered in
accordance with this chapter and the oertificate of tegistration of the vehicle has not been suspended or cancelled znd
the vehicle caries a registration mark displayed in the prescribed manner.

(b) Condition for exemption from registratión

For the purposc of the proviso to section 39, a motor vehicle in the possession of a dealer shall be exempted from the
necessity of registration subject to the condition that he obtains a trade certificate from the registering authority having
jurisdiction in the area in which the dealer has his place of business in' accordance with the provisions of tis chapter.
c Registration where to be made:

Subject to the provisions of section 24-A, section 25 and section 32 every owner of a motor vehicle shall cause the
vehicle to be registered by a registering authority in the State in which he has the residence or place of business where
the vehicle is normally kept.
t) Registration how to be made:
L An application for registration of a motor vehicle shall be made in Form 20 (Form E), by the owner to the
registering authority within a period of 7seven days) from the date of taking delivery of such vehicle, xcluing
the period of joumey and shall Be accompanied by:(a) sale certificate in Form 21; () valid insurance certificate
and other docunents as set forth in the first schedule, shal contain the information regquired by thnt form,amd shall
be accomplished by prescribed fee in rude 81.
2 The registered authority shall isue to ithe owner of a motor vehicle registered by ita certificate of registration in
enter in the a record to be kept by it parieulars of suxh
the form Gas set forth in the frst schedule and shall
certificate.
by ît umder
(Every registering authority shalf keep in Form 24 a permanent register of motor vehicles registered
registration marks are assignied by it umder sub
section 41 and of motor vehicles of otrer States for wtich new
registrafion numbers)
section (2) of section 47 and shall also enter in such record under the respective
,a distinguishing
3. The registered authority shall assign to the vehicle for the display thereon in the prescribe manner
the sixth scbednle
one of the group or letter allotted to the state by
mark or registration mark comsisting of the
followed by a mumber containing not more than four figures.

(e) Issue of certificate of registration:

documents firnished therewith, the registenu
On receipt of an application umder rule 47 and after verification of the
77 |certina
of the motor vehicle a
authority shall, subject to the provisions of section 44, issue to the owner concerieu ae
as may be specified in the Notification issued by the
Tegistration in Form 23 or Form 23-A,
the receipt ors
a
thirty days from
Government or Union Territory Adminístration] 72(withín the period of handed over
registration transport vehicle it shall rom
application: 69 [Provided that where the certificate of
pertains to a
the penod o
certificate of fitness in Form 38, 78 within
to the registered owner only after recording the
the date of receipt of such an application.

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 Engineering (MSBTE_Sem
ERUomobile
bile -V)
registration markconsisting
consistine
6-3 Motor Vehicle Act, Road
trade of the registration Safety and Garage Practices
A
section 41
and followed by two letters mark refcrred
example:
and a number in
red to in the notific
notification made under sub-section (6) or
containing
for not more than four digits for each vehicle,
Represent State Code.
MH:
Registration District Code.
12:K
digit number : Niumber for
Four
the vehicle.
validity:
Periodof
ficate granted or renewed
A trad under rule
35 shall
newai thereof and
renew
sSve or shall be efcctive throughoutbe in force for a pperiod of twelve months
from the e of
following classes of vehicles namely India Separate
: aplication shall be made
for each orthe
u
Motorcycle;
()
(6) Iavalid carriage;

(c)Lightmotor vehicle;
(d) Medium passenger motor vehicle

(Medium gods vehicle;

(0 Heavy passenger motor vehicle;

Heavy goods vehicle;

) Anyothermotor vehicle of aspecified

description
() Temporary registration:
Notwithstanding anything contained
in section 23, the owner of motor
or ofher prescribed
authority to have the vehicle temporarily
a vehicle may apply to any
registering authority
registered in the prescribed
prescribed manner of a temporary manner and for the issue in the
certificate ofa registration and
a temporary registration mark. A"
under this section shall be valid for period, registration made
a not excedingone month,and shall
not be renewable.
(h) Production of vehicle at the time of registration:

The registered authority shall before proceeding register

to a motor vehicle require the person applying for registration
of the vehicle to produce the véhicle either before itself such authority
or such as concened State Government may by
order appoint in order that registering authority may satisfy itself that the
particular contained in the application
are true
and the vehicfe complies with the requirement of chapter 5 (ChapterV- Construction, equipment and maintenance
of
motot vehicle) and the rules are made there under.

0 Refusal of registration

Maybe the registered authority ought to refuse to register a motor vebicle if the vehicle is mechanically defective fail
ör
to comply with the requirement rules are made there under or the if the
of Chapter orV the aplicant fail to furmish
particular of any previous registration.

Suspension or cancellation of registration certificate:

permanenty incapable of use, the owner shall within the
a motor vehicle has been destroyed or has been rendered
authority ithin whose jurisdiction he reside and shall
10urteen days or as soon as may be reported to the registered
1Orward to that authority certificate of registration of the
vehicle together with any token or card issued to authorized the

ISe of the vehicle in a public place.

Tech Knauledge
Pubileations

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 64 Motor Vehicle Act, Road Safety and Garage Practices
Automobile Engineering (MSBTE_Sem-VI)

any registration certificate has not complied with the

If the registering authority has reason to believe that the holder of
provisions of niles 39 to 43, it may, after giving the holder an opportunity of being heard,
suspend or cancel the

registration certificate held by him.

6.3 Driving License

The sccond chapter related to the various necessary

conditions for licensing of drivers of motor vehicle for drivino
ing
with the driving of motor vehicles, restrictions on the holding of driving
license like age limit in connection liense and
driving license. No person can drive a motor vehicle in any public place unless he holds the valid diving
grant of
motor cycle withort gea may be drivea by
license. For dfiving one shouid be at least eighteen years of age. However, a
a person after attaining the age of sixteen years.

.Any qualificd person.can apply for driving license to the licensing authority having jurisdiction in the area () in which
he ordinary resides or caries on business or (i) in which tie sehook from where he has recejved training in diving the

motor vehicle is situated. The diving

license issued only añter passing a test of competence to the saisfaction of the
licensing authority.
licensing authority. The learners' license can also be obtained from the competenm

A period for learner's Ticense is effective for a

six months from the äate of ts issue vwhile a driving license issued
o
renewed is (a) in the case of a transport vehicle, valid for three and (b) in all other cases,
. Fthe person obtaining or reviewing the license is not of farty years on the date of isue or renewals, is eftective far
forty years, whichever is earlier.
a period of twenty years or until the person attains the age, of

2. Ifthe person obtains renewing the license is already of forty years age is effective for a period offive yeans:
ftom its expiry as given above. The
However, every driving liçense contimues to be effective for a period of thirty days
possess a valid conductor's license.
conductor ofa stage carriage also is requires by law to

6.4 Control of Traffic

Linit of speed:
speed exceeding the
vehicle can be driven a motor vehicle or cause or allow a motor vehicle at a public place a
No maximum fixed for the vehicle by or under tis
maximum specd fixed for the vehicle, which in no case can exceed the
fixed to
maximum speed in no case exceed the maximum
act or notification in the official Gazette. Provide that such a
the vehicle in the eight schedules.

public place in any motor vehicle or trailer,

No person shall drive allowed be driven at a
registration
than the value specified in the certificate of
The vebicle, whose unladen weight is more
a)
certficate ofregistraton.
registered laden weight value specified the
in
laden weight which is exceeds than the
6) The sub-section, them a court may
charge motor vehicle or trailer driven in contravention of
A persom or the driver in of
motor vehicle or traler,
knowledge of the under of the owner of
presume that offence was committed with the
as sperunc
authority in this behalf may erect tratfic signs
For regulating the traffic, the
State Government or any control camot be arvc
signs. The vehicle with lef-hand No
Dchedule. It is the duty of every driver to
obey the traffic workingonder.
nature and in
signaling device of a
prescribed
likely to
undess it is eguipped with a mechanical orelectical position or
condition as is
place in Such a
any public
vehicle or trailer is to be abandoned or kept in rest on
the public place.
cause, dangeror undue inconvenience to the passenges
or other users of

edaoaidi
Psblitatie

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 Engineerin (MSBTE_Sem-V1)
obile Engineering 6-5
AutomobDVe
Motor Vehicle Act, Road Safety and Garage Pracices
of a two-whceled motor cycle can carry more
No ving on any motor cyclc than one person
has to wear a protective on the motor cycle. Further, every Peru
ridingor shicld
provisiondoes not
apply to a Sikh wearing
a turban. Signals and
headgear of prescribed description. However, this
additional safety measures
ures for transport motor vehicle.
driver of a
motorr vehicle
v shall make such signals
he and on such occasions as are pecified in the regulations made
section 118. speci
under
Vehicles shallal
also be required to install retro-reflective triangle
The colour
of the ttriangle fitted in the front of the
vehicleshallbewhite and that of rear shall be red.The location
of both the triangles shall be at least one meter above
ground ievel atth
t the front and rear, preferably at the centre
the purposes of "white colour warning
ofthe vehicle. For the purp
word
triangle', the red"
shall be substituted by word
"white", wherever applicable in AIS:0222001. The
retro-reflective
of white retro-reilective nportion shall be col
nts of
requirements
as per clause 8.5 of AIS:057 and. white fluorescent material sua
be
clause 7.1 of iSO:7591-82(E):1.
as per
a vehicle is involved in accident, the
driver of the vehicle
asonabfe steps to secure medrcal attendance for
the injured person and
or øther person in-charge of the vehicle shouju
if necessary, convey him to the nearest
a
hospital (unless the injured person, or case
his guardian in ofa minar desires otherwise, or unles it is not practcapieu
so On account of mob fury) and report the incident
da at the nearest police station as soon as possible, in any caSE W
twenty four hours of the occurence.

65 Insuranceagainst Third Party

,The third party Insurance is a safeguard equally for the diver as well as the victim. It ensures for meeting claims tor,
ompensation. The claim for damage to vebicle brought against the insurance is not covered by the minimum legal
requirement under this act The third party Insurance covers the following considerations.

Security against a claim for damage in case of injury or deanth of person or animaf or damage in case property of
the victim

) Liabilifies for medical expense of the third party..

(C). Legal expenses if any incurred.

This insurance is the simplest and cheapest of the diferet type of insurance.

No person can dive a veticle in a publio place unless there is in force in relation to the use of the vehicle by that
perscon, a policy of insurance against hird poliey risk. This however,does not apply to govermmont vehicle unconnected
with any commerciaf purpose
to
In case of transfer ownership of the vehicle to another person, the insurancee policy shall also be deemed. have been
However,
transferred in favour of the person to whom the vehicle is transferred with effect ftom the date of its transfer.
the transferee has apply to the insurer within fourtoen days the date of
transfer for making necessary changes in the
to
certificate of insurance which shall be done by the insurer
certiticate, on demand by a police oficer in uniform. The
The driver of a motor vehicle shall. produce the insurance
or an accident (except in case of the driver of a
certificate may however be produced within seven days of the demand
transport vehicle).

5.6 Claim for Compensation

by motor Acidents Claims Tnbunals, constituted by the stat
tate
The claims for. compensation are adjudicatd.
Government.
within ninety days from the date
Tribunals can be pretered to the High Court
An appeal against the award of a Claims
ten thousand nupees and after twenty five
account in dispute in the appeal is moreE than
of the award, provided that the deposited with the High Court
awarded, whichever is les, is
housand rupees or fily percent of the amount
Techfauledyë
PLBlieatians

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FAutomobile Engineering (MSBTE Sem-V) 6-6 Motor Vehicle Act, Road Safety and Garage Practices

6.7 Traffic sign

There are three types of traffic sign:

. Mandatory sign- The first schcdule contains 36 sign(M1 to M36)

2 Cautionary sign: 37 such sign (Cl to C37) have been given in the first scheduled.

3. Infomatory sign: 22 such sign (El to E22) are given in the first scheduled.

6.7.1 Central Motor Vehicle Rules

Pursuant to Motor Vehicle Act 1988,Central Motor Vehicle Rules comes into being inl1989. Brief content of these are

Chapter - Preliminary

Chapter I1 Licensing of Drivers of Motor Vehicles General

Chapter I1 Registration of Motor Vehicles Trade Cerificate

Chapter IV- Control of Tansport Vehicles Touist Permits

Chapter V Construction, Equipment and Maintenance of Motor Vehicles Preliminary

Fom 1 to 58-Forms are given to various proposes.

Annexture I-mass emission standard for petrol driven vehicles.

Annexture I1- Breakdown of the operating cycle for the test.

Annexture Il-Reference fuel type and production conformity test.

Annexture IV- Lirmit value ofexhaust gas capacity applicable to diesel driven vehicle.

Annexture IVA- Test cycle

Annexture IV B- Driving cycle and cold start

Anmexture IV c Reference fuel petrol.

Annexture IVD-Reference fue diese!.

Annexture V-Transport emergency card (road)

AnnextureVT-Specimen of objective examination of driveE

AnnextureVI-Check head lamp beam

AnnextureVII-Safety check for use of LPG fuel

Annexture X-Safety check for use of CNG fuel.

Amexture X - safety and procedural requirement for type of LPG and CNG operated vehicle

Chapter VI Control of traffic

Chapter VIl Insurance of Motor Vehicles Against Third Party Risks

Chapter VIl Offences, Penalties And Procedure

6.8 Classification and Definition of Vehicles

sun itable
designed to work with
Categeory T:"Agricultural tractor" means any mechanically propelled 4-wheel vehicle
materials. Agriculhural ra
implements for various field operations and/or trailers to transport agricultural
non-transport vehicle.
Kan
Tech

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 (MSBTE_Sem-VI)
Engineering 6-7
Motor Vehicle Act, Road Safety
semitrailer and Garage Practces
Trailer O,0,0, "Agricultural
CategeoryO: constructi which is coupled to
trailer" means
axles a trailer generally leftuncover
ble an agricultural
tractor by mea
agricultural materials. mcans of two hooks and predominantly
gSporting
edfir vehicle" means rubber
aent vehi
equipment
struction tyred (including
Constra selfpropeliled, excavator, loader,
exca pneumatic tyred),
backhoe, compactor rubber padded or steel drum el
ted, roller, durmper, wie
motor grader, mobile crane, dozer, 101
Hoading concrete mixer
ixer or any other construction
equüpment vehicle highway capabilities.
construction equipment vehicle šhall
Erplan
:A be a non-transport vehicle
the driving on the road of which is
jdental to the main off highway functiona
and fora short.
meansa motor vehicle whichis
1-transport vehicl notatransportvébicle.
motoroycle
tegaryL-"ameans a as defined in sub-section (27)
mo
of scction 2 of the Act, with maximun design speed
Ca 45 km/hour and engine capacity not exceeding
exceed 50 c, iffited with a thermícengine.
not

a 2
means a motor eycle as delincd n sub-sectíon (27) section
of 2 of the Act, with maximum design speed
km/hour and engine capacity exceeding50 ce, if fitted witha themic
ing 45 engine.
means a motor vehicle with at least four wheels used for the
M
"Catgory cariage of passengers and their luggages
motor vehicle used for the cariage of passengers and their lugage and comprising no more
Cate20C MA" means a
than eight
seats in addition to the driver's seat;
carage of passengers and their luggage and comprising more than
Cat gor M-2" means a motor vehicie used forthe
stedory
not
addition to the driver's seat and having a maximum mass exceeding tonnes.
5
ioht seats in
passengers and theirluggage and comprising more than
uised for the cariage of
,"Category M-3" means a motor vehicle
mass excéeding 5 tonnes,
driver's seat and having a maximum
eioht seats in addition to the
goods;
least four wheels used för the cariage of
with at
."Category N"means a motor vehicle not exceeding 3.5
carriage of goods and having a maximum mass
"Category N-P means a motor vehicle used for the

tonnes
tonnes. amaximum mass exceeding 3.5
goods and having
vehicle used for the cariage of
"Category N-2" meansa motor
but not exceding 12 tonnes. mass exceeding 12.
goods and having a maximum
motor vehicle usd for the carriage of
aegory N-3" means a microprocesor chip mounted
Lonnes. executing commands which is a
Organization for
capable of storing data and specified in the
Intemationa
Sart Card"means a device card and chip are
as may be
amended from
dimensions ofthe 7816
specifications,
card and the Commission (EC)
&plastic Technical
aTdization(ISOInternational Electro electric motor
specifñicd in Anmexure exclusively by an
specifications powered
as per the and the following
1 time, and shall be upon roads vehicle: Provided
that if
for use
means a vehicle adapted installed in the vehicle shall not
Battery Operated Vehicle traction battery battery operated
by 126, the
.supplied exclusively specifiedinrule
whose energy
traction energy is
authorised by any
testng agency

conditsions a verified and

be deemed to be a motor vehicle kW.
than 0.25
motor is less
the thirty minutespowerofthe km/h;
less than 25
the vehicle is Kassedyi
the maximumspeed of
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 Garage Practices
Automobile Engineering (MSBTE Sem-V) 6-8 Motor Vehicle Act, Road Safety and

Bi-cycles with pedal assistance

which are
power less than 0.25 kW, whose output is
u with an auxiliary electic motor having a thirty minute
progresively roduced and fimaly ent ofas thie vehicle rosches a speed of 25 km/t, or so0ner,ifthe oyelist stops
pedaling; and

cdthe rear.withsuitable brakes and retro-reflective devices, ie, one white refiector in the front and one red retcctor
Explan
Thethirty mimte power of the motor is defined in AlS: 049:.200s and method of verification is
AS: 041:2003, ill te coresponding BIS specificafions arc ofifed under the Bureau of Indian Slandards
in
Act, 1986 (63 of 1986).

oE means an agicultural machinery used

C
ravel and its
for soil prteparation having a single axle in which the direction o
control for field operation
is performed by the operator walking behind it. This equípment may or may not
kVE a Tding attaciment and when coupied
to a trailer can be used for the transportation of goads. Tbe maximum spee
OT DE power
tiller when coupled to trailer, shall
a not exceed 22km/h. The maximum haulage capacity of the PoweT
tiller coupled to trailer
a shall not exceed 15 tons.
6.9 Enforcement of Emission
Norms
EmissionStandard

EmIssio standards are requirements that set specific limits to

thie amouit of pollutants that car be released
environment Many emissions. standards focus on regulating nto the
polutants released by automobiles (motor cars,
powered vehicles but they can also and other
reglate emissions from industry, power plats, small equipment
such as lawmowers
and diesel generators. Frequent policy altermatives
to emissians standards are technology standards (which mandate
Standards generally regulate the emissions
of nitrdgen oxides (NO J,sulfür oxides, particulate matter (PM) or soot, carbon
monoxide (Co), or vofatile hydrocarbons.

6.10 Types and significance of Traffic Signs

Traffic signs that provide information: Informatory trafic signs provide information
to the driver via the boards.

Traffic signs act as silent conductors of the trafic on the road. Any person who holds
a driving licence and is eligible to
drive a vehicle should have proper kaowledge of trafiñic signs. The government has made it mandatory
for any persou who
wants to obtain a driving licence to be wel-versed with the traffic signs

Functions of traffic signs

Knowledge of traffic signs for any driver is necessary as tney pertom certam finctions which are essential for road
signs are:
safety. The functions performed by traffic
specific destination.
1. The distance left to cover to reacha
destination, if any.
2. Atermative routes to the specific nohlfe
as sehools, coleges, workplaces. ehike nlares
cautionary traftic signs are also displayed such
3. Locations on the
and restaurants.

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 _Sem-V
mobile Engineering (MSBTE
6-9 Garage Practices
Au reventthe
prevent undesirable ri
the undesirable
enicle Act, Road Safety and
raffic signs
Tralih risks posed on the road to drivers
and the passengers in the vehicle.
Traffic that order has ensued
on the road and signs are followed properly, the
chances or
d and if the sign
aecidents occuming are greatly minimized.

Trafisigns alsohelp in
casy navigation ofthe
routes.

PartA uatony
Mandatov.cirne
signs

SPEED

20 LIMIT
- Letters and figures
in white

Red disc 60cm Dia

Definition plate

Post painted in 25cm

black and white
bands

G
ITTipmmin

Fig. 6.10.1

ENote case where this sian

as ant exampleine actua: igure wl be prescnbed im eaci
The Fig 8:10.1 1s gen merely
s isSUed
Ni given Jor gulda
nivenJO
negeneraldesign orhe post
Is

or is fo be, imposed or
a certain:class or casses of motDr vehicle the class or
Where the speed limit is, maddition, generalspeed liminni
a
speeified ottekdefinition plateWhere or classes the genersl
2Classes wit ba imposed on vehicles of a certain class
a
motor vehicles special speed
limitis, or.is
to
angiNe
be
specal.spasenogener wtn the.class afclasses.of
vehicle tn
specified on the gisc
Speedlimit will be ate
L
wilTbespeciiC on the denRalo p
Which tapplies

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FAutomobile Engineering (MSBTE Sem-VI) 6-10 Motor Vehicle Act, Road Safety
and Garage Practices

No. 2Weight limits

CLOSED Red border

centre white
TO

60cm Dia-

Definition
over
20cm AXes
einctons
plate white

-50cm

No. 3 Total prohibition

No. 4 Direction sign

Arrow in
white
CLOSED White band

Red disc
Red disc

No.5 No parking

Red disc 60em dia

NO PARKING-White band

Fig.6.10.2

a definition plate placed below it as n n

Nofe Sgp No as.nere set forth may be ampftied y instrictOr n
dunngiWn
dehnition plate may be set forth the time
geheral,ar ent settorth: i Sig No of his pait 0pan the don
pron
manner an arrowhead inscrbed on the definition plate wiIL intake thaf patking is
paring is prohubited. In ike
nich the arrowhead points ES
Patokn Sreet or 00ad ying tO esie rone sg

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mobile Engineering (MSBIE Sem-VI)
6-11 Motor Vehicle Act, Road Safety and Garage

No.6 Overtaking prohibited

No.7 Use of sound
signals prohibited

Cross and border- Red

Red border Background-White
and band Device-Black .

No.8Main road ahead

DEAD
Red border
SLOW certre white.

60cm

White black ground

red border and barnd

55cm|
MAIN
ROAD
AMEAD

40 CIm

Fig. 6.10.3

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 Safety and Garage Practices
Automobile Motor Vehicle Act, Road
Engineering (MSBTE Sem-V 6-12

Part B:Cautionary.signs

8cm
Red border
45 cmy

-Centre white
or hollow

Explanatory
device
Plate while

45 cm NAll devices printed

black

Red border

Painted in 25 cm black and

white bands

Fig. 6.10.4
The signs of this part shall be used in conjuncion with a red triangular plate, the centre of which shall be either hollow
or painted white, in the manner indicated in the general design reproduced below.

Red borde

Red border

Red border
No. 2. Zig-Zagftef)
No. 2. Zig-Zag(Right)
No. 1. Rough road
Fig.6.10.5

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 ineering (MS
Engineering (MSBTE Sem-V)
Homobile
6-13
Motor Vehicle Act, Road Safety and Garage Practices
Redborder
Redborder

No. 3. Cross road Red border

No. 4. Level
crossing
(Guarded) No. 5. Level crossing
(Unguarded)
Fig. 6.10.6
Red border

Red border
Red border
No.6. Right turm
.No.6. Left turn
No.7. Schoot
Fig. 6.10.7
Red border
Red border-

Red barder
No. 8. Dead end cross road' No.9. Side road[Right) No.9. Side roadLeft)

Fig.6.10.8

Red border

Red border Red border

No. 11.Pemy No. 12. Hair pin bend(Aight)
No. 10. Steep hill
Fig. 6.10.9

Red border-

-Aed border

red borders
No. 14. Narrow bridge
No. 13. Hair pin bend|Left)

Fig. 6.10.10

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EAutomobile Engineering Practices
(MSBTE Sem-V Motor Vehicle Act, Road Safely and Garage
6-14

200 cm

160 cm

Red centre-H 100 cm

130 cm

White side

100 cm

60cm

Red 100 cT

30cm
White
30 cm

Ground
TTTITTR777ATITTITT

Fig.6.10.11

No.2. Road Junction Approach

Back grournd

Najafgarth

New delhi Rohtak

Fig.6.10.12

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 Practices
Garage
Road Safety
and
Sem-Vi) VehicleAct,
Engineering (MSETE_ 6-15 O1Or
le
Speed Limit Parking Sign
No. 3.End of No. 4.

P
Blue black ground
60 cm square

Fig.6.10.13

Emission Perfomance
Standard:
Vehicle
of emission control
emission periormance standard is a
limit that sets thresholds above which a different type
An limits for conventional
needed. While emission performance standards have been used to dictate
chnology might be be used to regulate
SO,), this regutatory technique may
such as Oxides of nrogen and oxides of sulfur (NO, and per
lutants
pollut pounds of carbon dioxide
gasses, particnarly carbon dioxide (CO,). In the US, this is given in
gTenbo
onhouse
suatt-hour (lbs. COMWhr),
and kilograms CO,MWhr elsewhere in the world.
megawatt
1989. These idle emission
emission regulations were idle emission limits which became effectíve in
Indian
The first vehicles, which were
werë soon reptaced by mass emission limits for both petrol (1991) and diesel (1992)
regnlatiorns regulations for
European emission and fuel
tightened during the 1990s, Since the year 2000,India started adopting
gudhully vehicles.
own emission tegulations still apply to two- and three-wheeled
faur-wheeledlight-duty and for heavy-de. Indian
first two
is renewed each year after the
requirement is that all transport vehicles cary a.fitness certificate that
Current
years of new vehicle registraton
for 11 major cities.
2003-Bharat Stage lI (Equivalent to Euro I) Nons
Equivalent to Euro Il) Norms for ii major cities.
2005-From April Bharat Stage lI
4-wlicelers för entire country whereas Bharat Stage IV (Equivalent to
2010-Bharat Stage III Emission Norms for
on (similar to Euro Il but diluted)
Earo IV) for 13 major cities. Bharat
Stage IV also has norms OBD

Emission of smoke, vapour, etc. from motor vehicles

exceeding 70 ce, manufactured prior to the first
motor cycles of engine capacity not
IC1) Every motor vehicle other than standards
be so driven so as to comply with the
day of March 1990, shall be
maintained in such condition and shall
259 October 2004, every motor vehicle operating on:
prescribed in these rules.] I2) On and after 1st
(CO) and Hydrocarbon (HC)
emission standards for Carbon monoxide
9Petrol/CNGLPG shall comply with the idling
given in the Table 6.10.1 below
Petrol/CNGILPG Driven Vehicles
Table 6.10.1 :

n-nexaneequivalent) ppm
ST No. Vehicle ype
4.5 9000
(2/4-stroke) (Vehicles
1
2 and 3 Wheelers
2000)
manufactured on and before 3Ist March,

(2-stroke) (Vehicles 3.5 6000

2 2 and 3-Wheelers
manufactured after 31st March, 2000)

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 Sarery and Garage Practices
Automobile Engineering (MSBTE Sem-VI) Motor Vehicle Act, Road
6-16
ppm
HC(n-hexane equivalent)
Sr. No:
VehicleTyphe Co %
4500
3. and 3-Wheclers (4-stroke) (Vehicles 3.5

manufactured after 31st March, 2000)

750
0.5
Bharat Stage 11 compliant 4-wheelers
4 1500
3.0
5. 4-Wheclers other than Bharat Stage II compliant
1169)O7EEa OOF Vehicles
instrument type approved as per rule on a course under
test shall be caried.out
Using the vanable
run of minimum 15 mihutes,
reheMVRJ with the vehicle engine
vranned up after a
rurining at idling speed and
tne samping probe shall b
vehicle engine shali be emisSion values recorded
uCconcitionDuring the test the a depth not less than 300mm. In case CO and/or H
system to owner snalu De advised to resubmit
into the vehicle exhàust the vehicle
SEed not wihin the limits, the testing
shall be
discontinued and
ompressed. Natural Gas
vehicles when operating.on
ne
rest.are
vehice after
repairlservice. Theidling
emission standards
Hydrocarbon:(NMHC) in place of
for
H) Hydrocarbon ard snal De
ESTTated by the

as -hexane equivalent Smiary idling

contain Non-Methane measured
NGshal
TOOWIng formula:
NMHO0.3xHC Where HC= Total
Hýdrocarbon
Petroleum Gas (Po) sha
contain keactve
Hydrocarbon
Total
operating on Liquefied fomula, RHC=0.5 X HC
Where HC
sandards for vehicles when
on
HG In place of
Hydrocarbon(HC) and shall be estimated by the following

Hydrocarbon measured as n-hexane equvalent.

6.11 Important Transport Termn 1989. Some

force on the Ist day of July,
Rules, come into
Central Motor Vehic
These rules may be called the
:
explained as under briely
depicted in different chapters are
important motor vehicle rules definitions of different words and
and commencement as well as various
the short title, extend
The first chapter explains definitions are as under :
terms used in this Act. Some of the inmportant the power of propulsion is.
adopted for use roads whether
mechanically propelled vehicle
"Motor vebicle" means any not been attached and
and includes a chassis tó which a body has
intérnal source
transmitted thereto from an exiernal or type adopted for use only in a
running upon fixed rails or vehicle of a special
not include a vehicle
a trailer: but does
premises.
any other enclosed the unladen weight of
weight of which, inclusive of
a two wheeled motor vehicle, the unladen
"Motor cycle" means attached to motor vehicle does not
exceed 600 kilograms.
detachable "side car" having an extra wheel,
any and load certified and
the total weight of the vehicle
means in respect of any vehicle
"Gross vehicle weight"
authority as permissible for that vehicle;
registered by the registering
vehicle weight of
velhicle" means anty goods cariage the gross
Heavy Goods Vehicle) heavy goods
HGV:"A( exceeds 12,000 kilograms
road-roller the unladen weight of either of which,
which, or a tractor or a
vehicle or
vehicle" medium goods vehicle" means any goods
camiage other than a light motor
MGV: "Medium goods
vehicle;
a heavy goods
vehicle weight
motor vehicle" means a transport vehicle or omnibus the gross
LGH:"Light goods ehicle (LGV)ight does not exceed1,00
tractor or road-roller the unladen weight of any of which,
ofeither of which or a motor car or
kilograms,
carriage of passengers tor re
"Public Service Vehicle" means any motor vehicle used or adapted to be used for the
or reward, and includes a maxi-cab, a motor cab, contract carriage, and stage carriage;
a puivate
"Transport vehicle" means a public service vehicle, a goods cariage, an educational institution bus or
service vehicle;
cts as
"Driver" includes, in relation to a motor vehicle which is drawn by another motor vehicle, the person wnd a
steersman of the drawn vehicle;
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 bile Engineering (MSBTE Sem-VI)
6-17 Motor Vehicle Act, Road Safety and Garage Practices
vehicle"
for vehicle" means a transport
pleaxy-motor vehicle or omnibus
(any vehicle constructed
six
personsexcluding the driver).
and run motor accident"
or adopted to cary than
o
Acident: "hit means an accident
arising out of the
identity whereot cannot be use of a motor vehicle or motor
ohicles the
he ascertained in spite
of reasonable efforts for the purpose;
scheme framed under section 163.
(c)"scheme meais
the
aanization Structure ofMotor Vehicle
(RTO) Department
612
department functions under
Transport t the provisions of section
213 ofMotor Vehicles Act, 1988. The Transport
nt primarily
is p
Departmentis established for enforcement the
of provisions of Motor Vehicles Act,1988.
cles Act,1989 and the nules framed under these two Acis.
The Transport Department is headed by the
,M Transpon
Commissioner (IC), He is asisted by Joint
Director and OSD specializing in Enforcement, Admimistration
the Head office.
andFina
in
Organization structure of Commissioner
of Transport
Ports and Transport
Department

Commissioner of
transport

Jointdirector
RUles and OSD-1 oSD-2 Account
Regulations o LTOffice (Estalblishment MVP Officer Field
Research
Cfficer
Modernization
Motor Vehicle Inquiy (Leal)Accounts Audit Officesl(Statisic)
Act. Check Posts Road $atety)Tax and Pemit) Planning)
and Enforcement)

RTO Offices ARTO Offices IMV Offices

Checkpcsts
(14 Offces) (12Oficas) (2 Ofices)

Pemanent Temporary
OSD-Officer on Special Duty offioes (3 offices
MVP-Motor Vehicle Prosecutor
RTO-Regional Transport Office/Officer
IMV- Inspector Motor Vehicle

&121 Regional Transport Ofice (RTO):

Officer. AIMV is an abbreviation for
Assistant Inspector of Motor
'RTO is an abbreviation for Regional Transport
Vehicles
the Government of India with a primary
Transport Office. It is an organization of
KLO is also called as the. Regional Union Teritories of India.
States and
DoUve to maintain the database of al the vehicles in different
Motor Vehicles.
execute the activities and the functions, as per the
ff every city andstate, there is a different RTO to
head of the departments in the specitic states.
A, 1983. And the Transpart Commissioner is the
which are allotted under specific series in a particular state. The
am is to ensure proper functioning of vehicles
Region Transport not taxed. The role also involves identifying the cars entering
onal Office identifies the vehicles that are
caught on
et Indian states. RTO also keeps a tab of vehicles exceeding the prescribed speed limit on the roads as

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 and arage Practices
Motor Vehicle Act, Road Satery
Automobile Engineering (MSBTE Sem-V) 6-18
the speed cameras drvimg licenses, tax
re-registration, transfer of ownership, I5sung
responsible for vehicle registration, and checks for
RIO or a state is certificates to transport vehicles
likewise. Furthermore, the RTO officer grants fitness
collection and the
the validity of the motor insurance policies. the RTO Eervices are
online. Nowadays, al
vehicle registration or do it
ofice physically for
uC in VISit the RIOofficial site of every state.
available online of the
AlMV:
6.12.2 Duties and Responsibility of RTO and as enforced by the
rules and the Motor Vehicles Act,
the central and state motor vehicle
npiement the provisions as per
Government

2. Conducting driving tests

licenses
3. Issuing and renewing the driving

4. Inspecting the vehicle insurance

5. Clearing the pollution test

duty
and road tax/excise
6. Collection road fund licenses
of
7. Vehicle registration
licenses
8. Granting international driving
public transport licenses
9. Providing freight and vehicles
database of the registered
10. Maintaining the
registrations
I1. Selling customized
loan transactions
12. Vehicle transfer
and registration of
rickshaw drivers
13. Providing badges to
the taxi and auto
vehicles
assessment of the accidental
14 Conducting the mechanical
transport vehicles
15. Issuing the fitness certificate to

Functions
and reports needed repairs.
lines and electric circuits,
1) Inspects truck accessories, air
malfunctions
and drives velhicle to detect
Examines vehicles for damage,
2) mechanical or electrical devices.
for wear, damage, or
improper adjustment, using
3) Tests vehicle components
rejection sticker to vehicles that fail.
sticker to vehicles that pass inspection, and
4) Applies inspection
for follow-up action by owner or police
5) Prepares report on each vehicle
delivered.
6) Prepares and keeps record of vehicles
truck trailer.
Positions trailer and drives car onto
owners having illegal equipment installed on vehicle.
8) Notifes authorities of

6.13 Passenger Comfort and Safety

and Sharpe increase in the vehicle sales, traffic
accident have become increg
With the development of society, technoiogy
technology automotive
frequently and serious. At the same time with the rapid development of science and
rapidly improve
he
increased road saieiy
acts are progressing in the right direction is the fact that due to
The proof that these regulatory ificant
This signi
volume of traffic tripled.
umber of fatal accidents in the last two decades has decreased, while the
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 bile Engineering (MSBTE_ Sem-V) 6-19 Motor Vehicle Act, Road Safety and Garage Practices
achieved due to improved vehicle safety
progress has been and, not least, through upgrading and
improvin
The noise level has reduced by about 90% since
jprs rs
manufacturers
themsel
themselves are developing a variety
the 1970, and if we stay in this period. Vehcke
of safcty features that. are intended
to increase the safery of the
The main purpose of
main o vehicle safety is life and health of the
yehicle. vehicle crew, but also other road users.
consideration for salety of an automobile is of two
type
.The
Active safety:
afety: Chances of accident should be minimize or to prevent the
chances of crash by providing certain
fication to the driver:. This is caled active safety
ndica
satety.components are
Active

I.Travelsafety
Conditioal safety
2
Perceptual safety,
3.
Techrical requirements of active safety, which include

braking

steering effort

an andio
alarm
assembly
tyre
front view

defrosting and demisting of the windscreen

devices for indinect vision (mirrors)

speedometer and reverse gear

wiper and windscreen washer

Connecting devices etc.,

4 Operator.safety:
driver should be minimum. called as passive safety.
1) Passive safety :lf the accident occur injury to the passengers and which are useful in
safety includes all actions associated with the vehicle,
Extemal safety - thie term passive outside the vehicle (pedestrians, cyclists). Factors that determine
minimizing injuries in road traffic collisions and
body during deformation, and the extermal shape of the car body.
the external safety are the behavior of the car acceleration
those kind of measures that are minimizing the
Internal security- is the protection of the vehicle by space
) passengers in the event of an accident, and also provide enough for survival
and initial internal forces on the vehicle.
components of the vehicle to rescue passengers from the
and ensure the operability of the critical
Important for passenger safety are:
dcfomation,
o the behavior ofthe car body during
accidents,
passenger compartment and a large living space during
.strength of the
a restraints,

o. deceleration systems,

0 bumpin the interior,

ocontrol systems,
deliverance of passengers,
a fiprotection,
etc.

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 Practices
Automobile Engineering MSBTE Sem-VI) 6-20 Motor Vehicle Act, Road Satety and Garage

1 Air Bags:
respectively individual body
knee, front to rear passengers) - Prevent the
collision of the body,
(front, window, side,
absorb shock and reduce the risk of
steering wheçl, instrument panel and other interior parts of the vehicle
parts ot the
injury.
drivers significant data to
to mitigate or prevent injuries among
AlrDags are passíve safety features designed
demonstrate their efectiveness. Airbag

Nitrogen gas

Crash
sensor

Inflator-

Fig. 6.13.1:Air
Bags
sensor. The bag and
itself, the intlator unit and the Crash
the bag passenger compartment of a
composed of three basic parís:
Airbag systems are Most often, the sensor is located in the
module.
together in the airbag
inflator are contained detected.
it is quickly
towards the front, so ifa crash occirs nitrogen gas that quickly
inflates the
vehicie and inflator to produce
it triggers the clectromechanical ball-md-tube
sensor,detects rapid deceleration, the
When the crash commonly used type of sensor is
cscape from its module. A
bag, causing the bag to
held in place
design. steel ball on the other
mechanical switch at one end and a
sensor is made up ofa tube with a loose from its place, rolls
down the
This type of
forceful deceleration occurs, the ball is knocked
by a magnet. When
a sufficiently

the cireuit closed, the iflator

switch.
tubeand hits the
circuit that inflates the, airbag to close. With
the, clectrica, effcctively to the occupant from
Hitting the switch causes high rate of speed prevent
must deploy at a very
engages to deploy the airbag. Air bags
vehicle.
hitting the hard interior of the

Seat Belts: also redace the

2 designed to keep drive and
passenger inside the vehicle. They
During the event of a
crash, seat belts are the following
wheel, dashboard or windshield. New seat belt designs have
the steering
risk that driver collide with
improve seat belt performance:
additional features that
shoulder strap to accommodatea
adjustable upper belt to change the position of the
Adjustable upper belts :An
increases shoulder belt comfort.
person's size. This feature since
slack, almost instantly in a crash.
These are retracts the seat belt to remove excess
() Seat belt pre-tensioner: an impact
not powerful enough to pull body back into seat in the event of
pre-tensioner are
a vehicle against
harmful movement an
it is designed to secure the occupant of
A seat belt is called a safety belt,
belts. intended to reduce injuries by stopping the wearer
from hiting hard nter
Cident or a,sudden stop. Seat are
prevent the pas
passengers are in the corect position for the airbag to deploy and
nts of the vehicle, or other any su
designed to stretch during
vehicle. Seat bels also absorb energy by being
interior, and ai o
ng thrown from the
there is less speed differential between the passenger's body and their vehicle
S0 that
Techlauledgs
PDICAtioas

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 tomobile Engineering (MSBTE Sem-VI)
6-21 Motor Vehicle Act, Road Safety and Garage Practices
d the
loading of impact on the passengers
spread body.
Aficr a passenger'sbody hits the car
interior,
o airbag or seat belts, is that
force of this impact is the of the internal organs hitting the ribcage or
skaul. The force mechanism
c
seques of
cnergy

work
dissipating and
together
through which
speed reducing technologies
car
-
crashes
crumple
cause disabling or life threatening injury.
zone - seat
1bc
designed to as a system, to reduce belt- airbags-padded interior, ae
the force of this final
impact.
collapsible Steering:
2 Callapsible stecring
column-
incase of an acident it reduces the
steering driver's isk of hiting
This mechanism 1s introduced the steering wheel.
to enhance vehicle
causing serious injured. safety when colision occurs to protect the
driver from
L Steering column assembly
Steering cofumn
2
3. Intermediate shaf

Universal joint
.
4.

5. Power assisted steeninmg column comnecting

the gearbox
Collapsible steering column consists
of a long shat. Thelong shaft consist
ntermediate shaft wish inner and outer sleeve. of two shafts or cohumn interlock with
the
The outer sieeve is present
on shaft connecting the gearbox.
The sleeve is provided with mumber
of steel bearings pressed in between sleeve, the inner shaft slip
housing like a telescopic maner and when compressed to inside the
during crashed occurs by absorbing
energy from the impact
The long shaft is connected the steering wheel to the vehicle's
gearbox

Steering colurn
assembly

Itermediate shaft

Steering coluen

Universal join

Power assistet
steening gear bax

Fig. 6.13.2: Collapsible Steering

8.14 Automobile Maintenance System

A Garage

room,
A garage in general is. a place. where cars stored and cared. for it includes departments like storing, sales
auto-supply department, oil and accessory sales. It also provide maintenance service in case of tyres, battery, Iubrication and

Tuning repair. t should be very well equipped for providing petrol, tubrication and washing bay as well as for tyre
and

bacry Service. For major works it may not be necessarily having the equipment. Although there would be available
qupment's air compressor, car lift, jacking facilities and axle stands, etc.

Techfaratrd

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 Garage Practices
Automobile Engineering (MSBTE Sem-VI) 6-22 Motor Vehicle Act, Road Safety and

Service Station
mechanical service and minor repais,
A ServiCe station is a place where in addition to carc of the motor vehicle like
services that are required daily are
peol 1s supplied, cars are lubricated and
cleaned, washed and other types of simrpler
number of sections ike garage
includes number sections like garage general it includes a
Periormed, In general ît a of
body shop
mechanical
general service, major repair shop, tire shop, paint shop,
service, agency tor a
is usually
run in conjunction witn a saes
the equipment available is garage
AServce station is addition to repair service for that particular
vebicle.
type motor vehicle to provide comprehensive different.
PAcnar of like lifting tackle and
added with specialized equipment
will be type and make of the
ne cquipment available, in a general garage adjusting and repair of particular
specially designed for checking,
pes o1 Jigs, Ixtures and tools machine, etc.
of a machine shop having a lathe, driling
vehicle. A service station may consist surtace grinder,
grinding machine, valve retce,
like crank shaft
station special types of machines
In case of big service equipments.
drum lathe also will be
reboring and boring machine and brake
shops
Workshop: The specialist repair
service station will be attended.
where works not
attended in
workshop
tis an engineering responsibility
line.
need expertsin their particular well as take off the
repairs at reasonable charges as welding jobs
attending to repairs, painting and
provide good service in electrical repair, radiator
They usually Similarly the
service station men.
from the sboulders of the
šend specialist repair shop.
aswell as body wörk can also be to
cars at the retail level,
Dealership: business that sells new or (old)used
vehicle local distribution is
a their
autonobile dealersbip or automobile salespeople to seli
A
automaker or its sales subsidiary. t employs technicians to stock and
contract with an employ automotive
based on a dealership maintenance.services for cars, and
provide
automotive vehicles. It may also
process warranty claims.
spare automobile parts and
sell
Sigaificance ofdealership: ensure there is no problem
inspection of vehicle before and after sale to
vehicle dealer conduct
1) Itis important that
properly.
and all ports are working
as registration plate, road tax
work process done form
Vehicle selling and purchase
2)
customer.
3) Dealer
eliminates the complaint from
availability of vehicle to their
potential of customer.
information about
4) He provides
Service station:
6.14.1 Signiñcance of Garage, Workshop,
certain kilometers on its normal
running
servicing is carried out when the vehicle completes
.Vehicle maintenance and proper perfornance. It is suggested
that the vehicle owners cary out
regular and
vehicle does not give
or when the
periodical checks on their vebicle,
after the vehicle has
maintenance procedures caried out at a set time interval or
A motor vehicle service is a
series of
manufacturer in a service schedule and
distance. The service intervals are, specified by the vehicle
travelled a certain
instrument panel.
some modem cars display he due
date for the next service electronically on the
servicing of a
speed and mileage on road. The maintenance of
obtained high standard performance, reliabilities,
To transmission, power:
vehicle as well as refitment like automatic
vehicle is required. So customer must service his
softer and
servicing the vehicle became more comfortable,
steering, power brake and engine compression ratio. After
and
easier to drive. The servicing is a process of maintaining and restoring
the vehicle to its original state of perfection
pertormance. The diffërent part usually fail or worn out dae adjustment, also detoriation of
some component occiurs

Constantly so to maintain vehicle completely trouble free state by the servicing is necessary.
Kaswledge
Tech

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 Enai
hile Engineering (MSBTE_Sem-VI)
AUTOMODle
6-23
Motor Vehicle Act,
Road Safety and Garage
Ensure Safety Pracices
. 2 PreventMalfunctioning
Performanc
1Increase Car 4 Ensure Fuel Efficiency
vehicle
5Prolong Lifeof 6 Reduce Polution

Low the Cost of Operation 8

1 Increase Resale
Value
Garage
Deryice Station
garage replaces and répairs are
in carried In service station fuel filling
and water servicing facilities are
on by the
skilled workers.
available. It has a small
workshop to provide repair for
particular make of vehícle.
I may have safes agency for
particular type of vehicle.

Petrol pump, washing bay, tyre and battery|All the equipment

2 in the garages plus small work shop tools,
servicing equipments are available VIZ. lathe, drilling machine,jigs and fixtures are available

Generally garage 1s located on main roads

Itis also locaáted on main roads or nearer to the highway.

6.15 Type ofMaintenance

There are four.types

of vehicle maintenance namely

Preventive maintenance
I
maintenance
2 Brake
schediule maintenance
Periodic maintenance (or)
4. Operation maintenance
road an some attention or
without breakdown or without giving trouble
Preventive maintenance: Prevention
1 Teduce or totally eliminate
preventive maintenance. It intends to
called as
maintenance taken to the vehicle is
reduces repair cost.
breakdownis accidents due to mechanical failures and
and
program leads to following advantages.
Agood preventive maintenance
vehicle
(a) Reduce the breakdown of
reduced breakdown
(b) Increased safety due to

c) Less expenses on repairs

spare parts
Good control on inventory of
required
) Lesser mumber of equipments are provided when a motor vehicle
maintenance is the attertion which is to be
Break down puncture, clectrical
Break down maintenance: during running These
faudts are started diffculties,
becomes immobilized due to faults created accidents etc.
overheating, fan beltings, breakage and
faults,
1anls, carburetors and fuel supply vehicle after
attention provided to motor
maintenance or operative maintenance is the
reriodic maintenance : Periodic quarterly, yearly
distance. These mantenance
may be done daily, weekly,
covered
operation for a specified time or
In garages this work is done on
the
2000 km, 4000 km, 8000 km of ruming.
after covering every 500 kn, 1000 km,
r so as to avoid road failhures and
to minimize break down
during use.
S O preset schedules
by the operator for
proper running of the vehicle is known as operation
Daily maintenance
peration maintenance : inflation, battery, brakes, clutch, smoke
proper working condition. Tire
Taintenance. It is needed to keep the vehicle in
maintenance daily.
and lights are checked in this
o07, staring system, ignition system

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 and Garage Practices
Engineering (MSBTE Sem-V) D-24 Motor Vehicle Act, Road Safery
Automobile

Advantages of good maintenance

1. Reduces the breakdown of vehicle

2. Increased safety due to roduced brcakdown

3. Less cxpenses on repairs

4. Increase the life of vehicle

spare parts
5. Good control on inventory of

6. To obtain the maximum, performance.

Need and importance of Record

Keeping:
6.15.1
on an individual vehicle. It
repair work performed
and
log is a historical record of the condition preventive maintenance,
A vehicle maintenance transport operators for
businesses to large
1s used by commercial
fleet owners ranging from small castings as
document both maintenance work/
Vehicle' mainteance logs can be used to
purposes.
Safcty, and record keeping
checks.
well as general vebicle inspection
running condition
comes to keeping it in good
I. Maintaining vehicle record is imperative when it
into big ones.
smallproblems before they escalate
2. tmakes it possible to take care of mumber or the
information and vehicle identification
information about make, model, insurance
3. Vehicles Record gives
VIN
Records Will Help to Keep Track.
4. Keeping Vehicle Maintenance
remind of repacement schedules.
information for a record of tyres. The type of tyre, mileage
5. tprovide
remind wheg to replaced again.
6. Aair and fuel line filter record will any
starting at purchase. A decreas in gas
mileage will be a good indication of
7. Keep detailed info on gas mileage
before they become a problem.
emerging maintenance issues that you can address
wihen your next change is due.
Type of oil used, date and mileage will help to keep track of
3. Write down all oil changes.
become unreadable.
Those little stickers in windshield may not last or
when to have old brake dust cleaned.
9. Record brake replacements.so when to keep an eye on wear or

10. This Helps with insurance or any vehicle issues that may have resulted from them.

II. t help for Schedule periodical maintenance

6.15.2 Listor record to be kept in service station:
The following record is should be Maintenance commonly caried out during a motor vehicle service include:

1. Changethe engine oil

2 Replace the oil filter

3. Replace the air filter

4. Replace the fuelfiler

5. Replace the cabin or alc filter

6. Replace the spark plugs

1. Check level and refill

bake fuid/clutch fluid

Tedvledgo
BICati

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 Automobile Engineering (MSBTE_Sem-V)
6-25 Motor Vehicle Act, Road Safety and Garage Practices
Pads/Liners,)
s/Liners, Brake Discs/Dnums
Check Brake
and replace
if worn out.
Coolant Hoses
Check
systems
Check the charging
10.
battery
Check the
I1.
Check evel and refill power steering fuid
12.
an refill Automatic/Manual Transmission
k level and
Chock
13. Fluid

Grease and lubricate components

14.

1nrnod and
replace the timing belt or timing
15.
chain if needed

Check condition ofthe tires

16.

17.
Check for proper operauon of all ights, wipers, etc.

Check for any Error codes in the ECU and take corective action.
18

19. Use
scan tool read trouble code.

VEHICLE MAINTENANCE LOoG

TOTAL
MAINTENANCE7n nG0 EAR 2003MAKE Dodge MODELB-3500UCENSE TEXASVIN NO
6100710
unkrow
0810
COsIS 098910091109 12 09 01 t0 02100310 0410 510
Erler Siarung venitaie
Mileage 15C00 21.000

at Mionta 21.000
Ertar Vehicle Mteago- at End
FVALEE PVALIEVALUEWALIE VALLE YALDE
Miontiy Mieage Tolals DO0 ALIE VALLE#VALUE 4VALUEVALUE
Total Mleage for Year
VALUE
Kalrtenance Cost Per
MieVALUE
VEHICLE WAINTENANCE COSTS
SERVICE
YPEOF
Oil& Fiter Change

Cnange s1000
AtFier
Fuel Fier Ghange

ransmission PdFLter
Enghe coolant
Cuoling System FUS
S400.00
r Hepair or Hepladement 2
e Rotabon or Eatanoe
Repacement $50.00
Hause
Brake flepat

nghe1ure Up,
Aligyemént
intd
POwerSrañngfBrake Fuid

COHeater Repai $3.00.0

6place Belts
Elaclncal Rapair
Bathery Repacernant

Batery Cables Terminals

Headighms ar Light Butbs

rdshiei Wiper sade

Wash& War
Miscelaneouis Service
S0080.00 $0.00S0.00 $0.00
ANENANCE COSTSs870.00s0.00$000 0 0

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 Motor Vehicle Act, Road Sarey
and Garage Practices
Engineering (MSBTE Sem-VI) 6-26
Automobile

Customer Name Last PM:

PM:
Unit #
Date:
Mechanic

Next PM Due on
. Appropriate Boxes Below
in
Instructions Write Initial
Greased and Comments and Parts
Repaired and
In spected Labed ist
TASK TO BE PERFORMED adjusted
okay

A Engine
I. Change oil and filter
tank cap
2. Change füel lines and
(25,000 ml)
3. Check fuel filter
needed
4. Check air filter if
5.Check spark plugs
rotor
6. Check distributor cap and
7 Pressure test cooling system
pressure
8. Check all boses under
tens loners
9.Check all belts and
and fan bearing
10. Check wáter pump
exhaust system
11. Check complete
oil Ieaks
12. Check for engine
Levels
BUnder he Hood Fluid
1. Radiator-note strength
2. Breke
3.Steering

4. Windshield washer
5. Automatic transmission
6.Rear end fluid.
or Station
6.16 Site Selection and Facilities Required for Garage Service
1. Important factors to be considered while location service station

2 Easily approachable

3. Idle sight
4. Availability of the vehicles in the surroundings
5. Availability of qualified and experience labour force (mechanics)
Kaulniyi
Tech
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EAtomobr
nhile
Engineering (MSBTE Sem-VI)
6-27
Motor Vehicle Act, Road Safety and Garage Practices

PrOvision of proper drainage

Prov
system
Samitation

Role And Responsibilities of Service Manager

6161 in service station

mabile service manager is responsible for directing

automobile
and coordinating all activities
An maintcnar of automotive equipments. involved in the acquisiton,
intenance
operationsand
mers and interactwith them to understand
customer
their vehicle problems.
Greet
vehic
yehicle with the technicIan and the customer to
the
Drivedhe gain firsthand knowledge ofthe vehicular
2 roblems,
estimat
mates including the services and repair
Preparethe cost costs and the cost of spare parts, if needed.

sdsin and manage a daily record of repairs and services of vehicles umdertaken and completed.
Mami
4
delivery fvehicles to customers on time.
Ensure
Handle.and manage soflytthe minor complaints and iitants with the customers.

Educate custome
tomers on maintaining their vehicles freefrom troubles and problems.
1.

pervise,
manage andImonitor-automotive service technicians and repairers.
8
needs in a cool, courteous and prompt manner.
a Handle customer inquiries and respond to their

ure10.
cUstomer satisfaction at the highest level
thirough effective šervices and repairs

service station
Role And Responsibilities of Service Supervisor
in
616.2

workers maintaining automobile.

responsibilities by overseeing skilled mechanics and
Performs supervisory
communicates with the superiors and
independently and in harmdhy with the automotive shop foreman and
Supervises
subordinates.
repairs and preventive
implements the smooth flow of general shop
Service supervisor organized the Schedules and
station
maintentance woskload for the service

Duties and Responsibilities of Service Supervisor

back repairs.
between customers and mechanics to eliminate in efficiency and come
L Service Supervisor communicates
repairs on buses and other light motorized equipment;
major and minor mechanical
Assign, supervise and participate in
diagmose diesel internal combustion
engine maintenance problems.
new techniques in mechanical repairs.
for employees with equipment suppliers for
Conduct in-service training programs
and schedule work flow of
and their assignment to personnel; plan, organize
arders
Delerine príoríty of work completion of work.
assigned personnel; assure timely
enployees as assigned; advise and assist
matches vehicles in system,
coordinates with parts person and updates
5.
oEVICe Supervisor ensures that parts
inventory
asinecessary.
maintenance recoris (hard copy
and computer).
EVICe Supervisor maintains preventive
or tools, toof room equipment, maintenance
and safety practices.

Supervisor must have an knowledge of

curent equipment and testers for effcient shop utilization.
ICe Estimat or services ae completed in a timely manner.
Tepair costs and makes sure that parts
10. Service or services are completed in a timely manner.
Ce Supervisor estimates repair costs and makes sure that paris
Supervi

Tech Kaeuledge

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 Garage Practices
Automobile Engineering (MSBTE Sem-/) 6-28 Motor Vehicle Act, Road Safety and

6.16.3 Role and Responsibilities of Customer Care Manager in service station

at al times. Duies imcfude
CUstomer dervice Managers are responsible for ensuring that customers are satisfied
ot customer
service training staff members to provide the highest standards
Supervising and managing the customer team,
direction to the CUstomer šervices
ensuring that all company policies are folowed. Providing leadership and
Service and
maintained.
of is provided and
Supervisors and their teams to ensure that an excellent standard service
customers and facilitate in growa.
customer service experience, create engaged
lmproving
problems through to resolution.
2. Taking ownership of castomers issues and following
towards that mision.
3. Settinga clear mission and deploying strategies focused

Responsibilities
grown:
and facilitate organic
customer service experience, create engaged customers timescales.
Lmprove confirmations within agreed
quotations, orders and order
lo ensure the accurate processing of customer
focused towards that mission.
3. Set a clear mission and deploy strategies
standards.
4. Develop service procedures, policies and
discussions.
customer service.actions and
3. Keep accurate records and document
reports.
6. Analyse statistics and compile accurate
can excel through
service agents and, nurture an environment where they
mentor and develop customer
.Recruit,
encouragement and empowerment.
efficient service to internal
Services function is adequately staffed and trained to deliver an
8. To ensure that the Customer
and external customers.
active member of the Senior
Management Team.
9. Torepresent the Customer Services function as an
the process of continuous improvement
in Customer Service standards within Caf
10. To actively promote and manage
Enquiries and Order Processing
spirit.
a
11. Create and sustain positive team
evironment displaying high levels of motivation and excellent team

12. Keep ahead of industry's developments and apply

best practices to areas of improvement

13. Control resources and utilise assets to achieve qualitative and quantitative targets.

14. Adhere to and manage the approved budget

15. Maintain an orderly workflow according to priorities

Review Questions

Q.1 Enlist the titles of various chapters of motor vehicle acts 1988.

Q2 Describe salient feature of motor vehicle act 1988.

Q.3 Descrbe salient feature of central motor Act rule 1989.

Q4 State the vehicle safety standard and regulation in india.

Q5 State the factors consider for site selection of service station.

Q6 Describe the role and responsibility of senvice

manager.

TechKasaledgi

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 iomobile Engineering (MSBTE_Sem-V)
6-29
Motor Vehicle Act, Road Safety and Garage PrauCEs
iferentiate Garage and service station.
Diffe
a7 scribe features of air
bag

State the functions of seat bels

Sta
rganisation structure of RTO Department
Draworga
a10
duties of AlMV
Enlist the
a11
Describe the importarnce of dealership and garage.
a12
to be kept in service to automobile.
Enlist the record
a13
sify need of
maintenance is reqitred to automobile.
Justiy
a14
responsibilit
bilities of customer care manager in service
State the station.
a15

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