SYLLABUS 1. Introduction 7 1.1 Definitions and specifying an automobile “ I 1.2 Automobile development and scope 1.8 Components of an automobile 1.4 Classification of automobile 5 Layout of chassis 1.6 Types of drives-front wheel, rear wheel, four wheel left hand, right hand 1.7 Body of super structure 2. Transmission System 2.1.2 Constructional details of single plate and multi plate friction clutch 2.1.8 Centrifugal and semi centrifugal clutch 2.1.4 Hydraulic operation of single plate clutch 2.1.5 Clutch troubles 2.2 Gear Box 2.2.1 4-Speed gear box 2.2.2 Gear ratios 2.2.3 Working of sliding mesh, constant mesh and synchromesh 4-speed gear box 2.2.4 Torque converter and overdrive 2.2.5 Transfer box 2.3 Propeller shaft and rear axle 2.3.1 Function 2.3.2 Universal joint 2.3.3 Final drive and differential assembly 2.3.4 Front drive axles 2.3.5 Rear axle drives and different types of rear axles 2.4 Wheels and Tyres 2.4.1 Types of wheels-dise wheel, wire wheel and alloy cast wheel 2.4. 1 Types of wheels-dise wheel, wire wheel and alloy cast wheel 2.4.2 Types of tyres used in Indian vehicles 2.4.3 Toe-in, Toe-out, camber, caster, kingpin inclination f 2.4.4 Tubeless tyres f 3. Steering System } 3.1 Function and principle | 3.2 Ackerman and Davis steering gears | 3.3 Types of steering gears—worm and ball nut, worm and wheel, worm and roller, rack and pinion type 3.4 Power steering 3.5 Wheel balancing 3,6 Wheel alignment4, Braking System 3 4.1 Constructional details and working of mechanical, hydraulic and vacuum brake 4.2 Details of master cylinder, wheel cylinder i 4.3 Concept of brake drum, brake lining and brake adjustment 44 Air brake, Emergency and Parking brake 45 Anti-lock braking system 5, Suspension System 5.1 Function 5.2 Types 5.3 Working of coil spring, leaf spring, rubber spring 5.4 Shock absorber-telescopic type 5.5 Air suspension 5.6 Strut suspension 6. Battery 6.1 Principles of battery operation 6.2 Constructional details of lead acid cell battery 6.3 Specific gravity of electrolyte—effect of temperature on specific gravity 64 Capacity and efficiency of battery 65 Battery charging, chemical reactions during charge and discharge 6.6 Maintenance of Batteries 6.7 Checking of batteries for voltage and specific gravity 6.8 Battery leakage test 7. Dynamo and Alternator 7.1 Dynamo 7.1.1 Function and details 7.1.2 Regulator—voltage current and compensated type 7.1.8 Cutout—construction, working and their adjustment 7.2 Alternator 7.2.1 Construction and working 7.22 Charging of battery from alternator '8. Lighting System and Accessories 8.1 Lighting systems 8.2 Wiring circuit] 8.3 Headlight, aiming of headlights 8.4 Lighting switches 8.5 Direction indicators 8.6 Windscreen wiper 8.7 Horn 8.8 Speedometer 8.9 Heater 8.10 Air conditioning 8.11 ‘Temperature indicator al aCONTENTS 1. Introduction 2. Transmission System 3. Steering System 4. Braking System 5. Suspension System 6. Battery 7. Dynamo & Alternator 8. Lighting System & Accessories ~ Appendix 1 Objective Type Questions & Fill Ups Appendix 2 Examination Paper 2014 (8) Appendix 3 Glossaries Technical Terms List of Practicals 1. Wheel Balancing 2. Wheel Alignment 3. Suspension System Servicing 4, Retreading and Recapping of Tyres 5, Automotive Brake Service 6. A/C System Service 7. Clutch Troubles and Clutch Service 8. Servicing of Fuel Injection Pump 9. Study of MPFI System 237 238 253 263 263 265 267 269 271 273 275INTRODUCTIO. 4.1 DEFINITIONS AND SPECIFYING AN AUTOMOBILE ‘Automobile : An automobile is a self-propelled vehicle driven by an internal combustion engine and is used for transportation of passengers and goods on ground. Examples : Car, bus, jeep, truck, tractor, motor cycle, scooter etc. The modern automobile, sn general is essentially a transportation equipment unit. It consists ofa ‘frame’ supporting the “ipedy”" and certain “power developing and transmitting units” which are further supported by “tyres and wheels” through “springs and axles.” ‘An “engine” supplies the power, which is delivered by the “transmission system” to the wheels through the clutch or fluid coupling. "Automobile Engineering : Automobile or automotive engineering is a branch of engineering in which we study all about the automobiles and have practice to propel them. Mobile or motive means one which can move. Automobile or automotive means one which itself can move. ‘The different names of the automobile are as follows () Auto (ii) Automobile (iii) Autocar (iv) Autobuggy (v) Car (vi) Motor (vii) Motor Car (viii) Motor vehicle (ix) Motor coach (x) Motor wagon (xi) Horseless coach. 1.2 BRIEF HISTORY OF AUTOMOBILE ‘The famous years in early automobile history are as follows + Year Event 1769 | French engineer Captain Nicholas Cugnot of France built the first road vehicle propelled by its own power. 1801 _| First steam carriage built by Richard Trevithick in England. 1804 _| Oliver Evans built the finest American self-propelled steam vehicles. 1827__| Onesiphare Pacqueur of France invented first differential. 1892_| First 3-speed Transmission patented by W.H. James in England. 1880 | German and French efforts developed an internal combustion engine vehicle. The present day automobile is the development of this vehicle. 1885_| Benz in Germany developed trieycle propelled by an internal combustion engine. 1886 _| One ofthe first gasoline engine powered automobile by Gottlieb Daimler of Germany. | 1894 | Panhard and Levassor in France developed vhich incorporated the chief features of the modern automobile. oe 1895 _| First motor car race held. - 1897 _| First car arrived in India, orAutomobile Engineering j T — —— — | 1900 | The design of the automobile was so improved that it awakened the public to the fact | that this new form of transportation was really practical for use: 1902 _| First volume of produetion car “The Curved Dash Oldsmobile” in America 1906 _| The production and sale of these vehicles became a business. 1908 _| Ford “T° model car produced in America by Ford Motor Company. 1911 _| First electric self-starter installed in the automobile. 1920_| There was a gradual change and refinement in automobile design. ‘The design development of recent years has provided the owners with cars that are © Safer; * Easier to drive; * Comfortable; * More reliable Note : “Germany is the birth place of the automobile. It was invented there, it went through its first paces there and it was developed there to a high level of technical maturity. The list of Germany automobile pioneers is a long one. Starting with Nicholas Cugnot, August Otto, Carl Benz, Gottlieb Daimler, Wilhelm Maybach and Rudolf Diesel and going all the way upto Ferdinard Posche and Felin Wankel.” AUTOMOBILE IN INDIA « In India the first motor car appeared in 1897. For about 50 years from 1897, India was an importer of automobile. + The late Bharat Ratna Sir. M. Vivesvaraya made an automobile industry in India, but the Government did not approve the plan. * In 1943 and 1944 two automobile factories, namely, Hindustan Motors Limited, Calcutta and Premier Automobiles Limited, Bombay were set up in India. ‘At present, several automobile companies are manufacturing automobiles. Uses of Diesel engines in Cars : Following are the advantages of using Diesel engines in cars: 1. Diesel fuel is much cheaper than petrol. 2. The diesel engine uses 50 percent Jess fuel in heavy traffic than does the available spark-ignition engine—one reason for extra economy is that diesel’s good low-speed torque makes it possible to drive at low speeds in a higher gear. 3. The high thermal efficiency of the diesel engine, reflected in low specific fuel consumption gives its high advantages in the matter of range. 4. The crankshaft speed of about 5000 r.p.m. enables the diesel engine to propel the cars at high speeds, with acceleration comparable to that of S.I. engine. 5. The use of diesel engine eliminates the complication of spark-ignition with its spart plugs, breaker points, condenser, ignition cables, distributor rotor and other components that. may have to be replaced several times during the life of engine. 6. Operating tests are further reduced by having no carburettor to service periodically. 7. Owing to the absence of electrical ignition equipment, non-volatile fuel and lower exhaust Meir © oe anaemic recta parma ee working in places and in the neighbourhood of inflammable material.Introduction 8. The special feature of diesel engines called: “torque back feature) makes it convenient for the vehicle to climb a step’ consumption at high load. Under these conditions diesel engines: Inspite of all the above mentior rejected from majority of customers, dite to their heavy weights vind smoke levels. These problems finally led to the development of efficient passenger can diesel engines. In this connection, therefe ‘= Over-square bare-stroke ratio; « Fast responding valve gear trains; © Cold starting equipments; = Combustion chamber design; Fuel injection equipment; = Solution of metallurgical problems to ensure satisfactory working life of alt components, crankshaft journals, bearings, cylinder hores and other bi components. ¥ “omPonetffee of German engineer Rudolf Diesel is memorable in Automobile and LC. history. He get very seriously injured when he successfully exploded coal dust as fuel. And in 1913 although he invented Diesel engine using liquid Fuel ‘Diesel’ but he committed suicide ashe auld not get financial co operation from his friend for his research and development, ‘ 1.3 CLASSIFICATION OF AUTOMOBILES % Automobiles can be classified with different regards which are as under = 1. _ | Purpose: @ Passenger carriers — | Car, jeep, bus ete. (ii) _| Goods carriers ayaa 2. Fuel used : (i) | Petrol vehicle — | uotae fei ace wagons ti) | Diesel vehicle = Pee Gas vehicle4 {utomobile Engineering Foan lie te % se ja | Medium Vehicle Station wagon, tempo, minibus and L small trucks. 4.__| Construction : ()__| Single unit vehicles (ii)__| Articulated vehicles and tractors. 5.__| Drive: Left hand drive Steering wheel fitted on left hand side | Right hand drive Steering wheel fitted on right hand side Fluid drive Vehicle employing torque converter, fluid flywheel or —_hydramatic a transmission |8.__| Wheel and axle: (i) | Two wheeler Auto cycle, mopped, scooter and motor cycle Gi) | Three wheeler Three wheeler scooter, auto rickshaw j and tempo. Gi) | Four wheeler (4 x 2 and (4 x 4) Cars, jeep, station wagon, pick up, trucks, buses. {ow Six wheeler (6 x 2) and (6 x 4) Six wheeler having two gear axles each having four wheels. Vehicles are classified by number of drive wheels wherein it is written 4 x 2or4 x 4 drive ete. In this case first figure indicates number of wheels and the second figure indicates number of drive wheels. In case of 4 x 4 drive, the vehicle has af wheels and all are drive wheels, however, it should be noted that wheels are considered as unit whether they have single tyre or dual tyre. Leaf spring Coil spring, torsion bar, pneumatic.Introduction | it)_| Delivery van/pickups 2 (iv) _| Station wagon (w) _ | Special purpose vehicle — | Ambulances, milk yan, workshop, mobile hospital ete. | I ‘Transmission : (i) _| Conventional — | All Indian vehicles | Gi) _| Semi-automatic (iii) _| Automatic j — | Most of British and Japanese vehicles. — | Most of the American vehicles. ‘A brief classification of the automobiles is follows : 1, Passenger Carriers : (i Light * Scooterets + Scooters + Mopeds «Motor eycles (ii) Heavy : + Buses = Single deck + Double deck 2, Goods Carriers : (@ Light Delivery Van Light truck (ii) Heavy ‘Truck ‘Tractor trailer. 1.4, PARTS OF AN AUTOMOBILE * Cars «Pick-ups © Station wagons * Coaches + Air-conditioned Every automobile consists of the following two main parts : 1. Machine portion 2. Carriage pattern or body 1.4.1.Machine Portion Every automobile irrespective of its country of manufacture or model consists of the following three basic units : G) The “chassis and transmission”, Gi) The “engine”, Git) The “electrical equipment”,Automobile Engineering Wheel and tyre Suspensi { Engine Steering axe —Axie shafts — fa Ty Z I Clutch Gear Universal Propetier shalt Fig. 1.1: Parts of an Automobile. 1.4.1.1. Chassis and Transmission Chassis : + This part of the automobile supports its body, engine and transmission system. + The automotive chassis includes the following : © The frame; © Springs and shock absorbers; = Steering systems; = Brakes; «© Tyres and Wheels. Transmission : * This unit transmits the power from the engine to the wheels. + It consists of the following : aA | Clutch; + Gear box; © Universal joint; © Final drive; © Axles and differential. 1.4.1.2. The engine : An engine in an automobile is the source of power..A petrol engine consists of the following = four basic systems described briefly below : (i) Full System : This system mixes petrol with air in the right proportion to give a mixture which when burnt produces pressure. This pressure is then used to move the pistons. (ii) Ignition System : This system of the engine provides regular sparks to set fire to the ‘mixture coming from the fuel system.Introduction (iii) Lubricating System : This system lubricates the moving parts of the they can work smoothly. (iv) Cooling System : This system with the help of water cools the engine and from getting hot Diesel engines incorporating similar/different systems are also used in automobiles. 1.4.1.3. Electrical System : ‘The automotive electrical system consists of the following : © The battery; * Dynamo; © Alternators; = The ignition starting and lighting systems. ‘This system starts the engine when the ignition switch is turned on. It makes the spark that ignites the compressed air-fuel mixture. + Ibalso operates the electric gauge head lights, indicator lights, brake lights, parking lights, wipers and also radio and cassette recorders if fitted in cars. 1.4.2. Body or Carriage Portion «tis that portion of an automobile where passengers have their seats or where the cargo to be carried is placed. «The body is designed according to the nature of cargo to be carried. The body of a passenger cartier is much different from the body of a load carrier, ic, the truck bus. Its design depends upon the utility for which the vehicle is meant for. It is made of either wood and steel or steel ‘alone. Modern research hai led to the development of plastic body. « Intrucks, tractors and certain other vehicles, a separate cabin known as ‘Cab’ is provided for the driver where the instrument panel and controls are housed. 1.5. COMPONENTS OF AN AUTOMOBILE The main units of an automobile are as follows : L. The basic structure. .. The power plant. The transmission system. The auxiliaries. The controls. 6. The superstructure. 1.5.1. The basic structure : This is the unit on which are to be built the remainder of the units required to turn it into a power-operated vehicle. It consists of the frame, the suspension system, axles, wheels and tyres. 1.5.2. The power plant: ‘The power plant (engine) provides the motive power for all the various functions which the vehicle or any part of it, may be called upon to perform. ‘The power plant generally consists of an internal combustion engine which may be ether of spark-ignition or of compression-ignition type. However, the gas-turbine has been used seepAutomobile Engineering 8 successfully in certain cars, though the cost has been a disadvantage in spite of their better performance compared to LC, engines Electric motors powered by batteries have been used as motive power plant for automobiles, Combination of an LC. engine and electric motor have been successfully employed in hybrid vehicles, Solar energy-powered systems have also been tried, but the most promising future power plant is the one based on fuel cells, which would give zero-emission vehicles. 1.5.3. The transmission system The transmission system consists of a clutch, a gear box, giving four, five or even six different ratios of torque output to torque input, a propeller shaft to transmit the torque output from the gear box to the rear axle and a differential gear to distribute the final torque equally between the driving wheels. The functions of a transmission system are : 1, To disconnect the engine from the road wheels when desired. 2. To connect the engine to the driving wheels without shock. 3. To vary the leverage between the engine and the driving wheels. 4. To reduce the engine speed permanently in a fixed ratio. 5. To turn the drive through a right angle. 1.5.4. The Auxiliaries : ‘The principal one out of these is that it is common to almost all types of the vehicles — is the electrical equipment. This can be subdivided into systems : (i) Supply system — Battery and generator (Gi) The starter. (iii) The ignition system—Battery and magneto ignition. (Gv) Ancillary devices— (a) Driving lights—head lights, side lights, tail light etc. (b) Signalling—horn, direction, indicators and brake light. {c) Other lights—inner roof light, reverse light, panel light ete. (d) Miscellaneous—radio, heaters, fans, electric fuel pump ete. 15.5. The Controls The controls consist of : (a) Steering system (b) Brakes. 1.5.6 The superstructure : In those cases, where frameless construction is not adopted, there must be a separate superstructure i.e., the body attached to the frame while in case of frameless construction, the body performs the functions of both. The body contains passenger and the luggage beside the engine part. 1.6 LAYOUT OF CHASSIS Chassis (also known as carrying unit) is a French term and was initially used to denote the frame or main structure of a vehicle.Introduction ‘The term chassis is now extensively used to denote the complete vehiele except the heavy vehicle having a separate body. The chassis contains all the major units propel the vehicle, direct its motion, stop it, and allow it to run smoothly aver uneven ‘The chassis of an automobile consists of the following comopnents suitably mounted Weare =P Gi)_| Front axle i Steering system | Civ)__| Rear-axle | Suspension system | (vi) _| Transmission ___ Brake system | wiii) | Engine Lax) ~ The chassis is sub-divided into : i) Power plant Gi) Running gear. ‘The power plant includes the engine assembly and power transmission assembly. The running gear includes the frame, steering system, suspension system, brakes, wheels and tyres. ‘The electrical system is part of both chassis and body. {All the above mentioned components are mounted in either of the following two ways : 1. Conventional Construction ; In this case a separate frame is used. 2, Frameless or Unitary Construction : Here no separate frame is employed. Out of these, the conventional construction is being used presently only for heavy vehicles whereas for cars the same has been replaced by the frameless type except of course by small manufacturers, who still find it economical to use frame. 1.7. BODY OR SUPER STRUCTURE Body is the super-structure of the vehicle. The chassis and body make the complete vehicle. In larger and heavier vehicles, the chassis and the body are each made asa separate unit and then bolted together. The body is usually made from a large number of steel pressings which are welded together. ‘The body is bolted to the chassis at numerous points, rubber or felt strips being interposed to damp-down vibration and noise. ‘The body of motor vehicle should fulfil the following requirements : () Light in weight, Gi) Cheap and easy in manufacturing. (iii) Attractive in shape and colour. (iv) Minimum number of components. (¥) Clear all-round vision through glass area. (wi) Long fatigue life. (vii) Minimum resistance to air. (viii) Good access to the engine and suspension system. (2) Minimum vibrations during running of the vehicle. (9) Adequate space for passengers and luggage.Automobil 10 Engineering All steel sections of the body are stamped out by dies separately and welded together. Decorative moulds and bands are formed around the window and door openings. The tendency of all steel body to drum or rumble is overcome by using insulating and sound deadening materials, The closed car body provides roof which may be used for luggage. + The closed bus provides a large space for luggage. = The open truck body does not have roof, It consists of surrounding side only. The rear side is only a half panel which may be opened down for loading and unloading. In some good trucks, the lower side panels may also be opened down for unloading. = ‘A car body is formed by a number of pressed steel panels welded together. For attaching the door, instrument, panel, hood, truck lid, head lining etc. attachment brackets are welded to the body. 1.7.1. Different types of bodies for various vehicles are listed below + i ‘Two-door sedan 2. Four-door sedan 3. | Convertible 4. Van 5.___| Truck Punjab body or Straight truck | 6. Truck half-body 7.___| Truck platform type 8 Truck with articulated trailer 9.___| Tanker 10. _| Dumper truck |i. | deep 12. _| Pick-up L13.__| Station wagon fe 1.8 TYPES OF DRIVES (1) Front-wheel-drive (2) Rear-wheel-drive 1. Front-wheel drive : Front-wheel drive layouts are these in which the front wheels of the vehicle are driven. The most popular layout used in cars today is the front-engine, front-wheel drive, with the engine in front of the front axle, driving the front wheels. This layout is typically chosen for its compact packaging. Since the engine and driven wheels are on the same side of the vehicle, there is no need for a central tunnel through the passenger compartment to accommodate a propshaft between the engine and the driven wheels. ‘As the steered wheels are also the driven wheels, FF (front-engine, front-wheel-drive layout). Cars are generally considered superior to FR (front-engine, rear-wheel-drive layout) cars in conditions such as snow, mud, or wet tarmac. The weight of the engine over the driven wheels also improves grip in such conditions. However, powerful cars rarely use the FF layout because weight transference under acceleration reduces the weight on the front wheels and reduces their traction, limiting the torque which can be utilized. Electronic traction control can avoid wheels pin but largely negates the benefit of extra toque/power. transverse engine (also known as “east-west” is commonly used in FF designs, in contract to FR which uses a longitudinal engine. The FF layout also restricts the size of the engine that can be placed in modern engine compartments, as FF configurations usually have Inline V-4 and \V-6 engines, while longer engines such as Inline-6 and 90° V8 will rarely fit. This is another reason luxury/sports cars avoid the FF layout. Exceptions do exist, such as the Volvo 580 (FWD/AWD) which uses transversely mounted inline 6 and V8 engines, and the Ford available with a 60° VB and all-wheel driveIntroduction 2, Rear-wheel-drive : Rear-wheel drive (RWD) typically places the: vehicle and the driven wheels are located at the rear, a configuration known a rive layout (FR layout). The front mid-engine, rear mi s n, This was the traditional automobile layout for most veh 1970s and 1980s. Nearly all motor cycles and bicycles use rear-wheel drive as srweshaft, chain, or belt, since the front wheel is tured for steering, and it wo difficult and cumbersome to “bend” the drive mechanism around the ties of the relatively rare exception is with the ‘moving bottom bracket’ type of recumbent | {he entire drivetrain, including pedals and chain, pivot with the steering from whe QUESTIONS th rear-wheel di layouts are also se SHORT QUESTIONS What is an automobile? What is a self-propelled vehicle? Give six examples of automobiles. State the basis on which automobiles are classified. Who built the first road vehicle propelled by its own power? Give examples of Indian manufacturers of scooters. - Give examples of Indian manufacturers of passenger cars. Name the components of electrical system. 9. Name the components of auxiliaries. 10. Name the components of chassis. LONG QUESTIONS Define the following terms : (a) Vehicle (b) Motor vehicle (c) Automobile (d) Automobile engineering Give the brief history of automobile. What are the advantages of diesel engines in cars? Give the classification of automobiles What are the different types of automobile vehicles? Describe briefly the following three basic units of an automobile : (i) The chassis and transmission (ii) The engine (iii) The electrical equipment. Explain briefly the main forces which oppose the motion of vehicle. Explain briefly the components of electrical system. i Explain the components of auxiliaries in brief. - 10. Explain the components of chassis in brief. eahep een