Automobile Lecture Series : BAJA SAE IITK
1 - BASICS OF AUTOMOBILES
-Rohit Arora
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
IDENTIFY MANUFACTURER -
BAJA SAE IITK : Basics of Automobile – Rohit Arora
1) CURRENT DRIVER STANDING IN F1 RACING?
BAJA SAE IITK : Basics of Automobile – Rohit Arora
1) CURRENT DRIVER STANDING IN F1 RACING?
1 Sebastian Vettel 256
BAJA SAE IITK : Basics of Automobile – Rohit Arora
1) CURRENT DRIVER STANDING IN F1 RACING?
1 Sebastian Vettel 256
2 Fernando Alonso 252
BAJA SAE IITK : Basics of Automobile – Rohit Arora
1) CURRENT DRIVER STANDING IN F1 RACING?
1 Sebastian Vettel 256
2 Fernando Alonso 252
3 Mark Webber 242
BAJA SAE IITK : Basics of Automobile – Rohit Arora
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
HOW MANY OF YOU HAVE SEEN SUCH A THING?
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
WHAT MAKES YOUR VEHICLE START?
•Any vehicle is basically a set of wheels with an engine to turn them.
•ICE forms the heart of most vehicles.
•It works on a mixture of fuel and air to produce enough power to turn a
shaft that turns the wheels.
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
WHAT MAKES YOUR VEHICLE START?
•Although people tend to think that most vehicles are totally powered by
fuel, many parts — the radio, headlights, air conditioner, windshield
wipers, power seats and windows, clock, and so on — actually function
on electricity, which is provided by the electrical system.
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
WHAT MAKES YOUR VEHICLE START?
When you turn the key in your vehicle’s ignition switch to Start or acti-
vate the ignition by pushing a button, you close a circuit that allows the
current to pass from your battery to your starter via the starter solenoid
switch
The starter makes the
engine turn over (that’s
the growling sound
you hear before the
engine starts running
smoothly).
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
WHAT MAKES YOUR VEHICLE START?
Now the fuel system comes into play.
When the engine is
running, fuel flows from
the fuel pump (usually
located inside the fuel
tank at the rear of the
vehicle) through the fuel
filter, to the fuel injectors,
into the intake manifold,
and then into the
combustion chamber.
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
WHAT MAKES YOUR VEHICLE START?
•Each pound of fuel is mixed
with 14.7 pounds of air to
form a vaporized mixture, like
a mist.
•The fuel/air mixture passes
into the cylinders in your
engine.
•A spark from a spark plug
ignites the fuel/air mixture,
causing it to burn and expand
rapidly.
•Piston starts oscillating.
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
WHAT MAKES YOUR VEHICLE START?
•Attached to the bottom of the
piston is a connecting rod that’s
attached to a crankshaft, which
leads, eventually, to the drive-
wheels of your vehicle.
•As the piston and the connecting
rod go up and down, they cause
the crankshaft to turn.
•To the rear of the crankshaft is
the transmission.
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
WHAT MAKES YOUR VEHICLE START?
• If your vehicle has a manual transmission, you’ll also find the
clutch located between the crankshaft and the transmission.
•The clutch connects or disconnects the engine from the rest of the
drive train. 19
•Remember, in a car with an automatic transmission, the clutch
action is done automatically.
BAJA SAE IITK : Basics of Automobile – Rohit Arora
WHAT MAKES YOUR VEHICLE START?
• When you shift into Drive (or First, if you have a manual
transmission), a set of gears causes the rest of the crankshaft (which is
called the driveshaft after it leaves the transmission) to turn at a
particular speed.
•The driveshaft runs to the rear wheels of conventional rear-wheel-
driven vehicles and ends in another set of gears called the
differential.
•The differential turns the power of the engine and the transmission 20
90 degrees into the axles that connect to drive wheels of the vehicle.
BAJA SAE IITK : Basics of Automobile – Rohit Arora
WHAT MAKES YOUR VEHICLE START?
•Vehicles with front-wheel drive or
with rear engines don’t require a long
driveshaft because the power source
is located right between the drive
wheels that drive the vehicle.
•On these vehicles, the transmission
and the differential are combined into
a single unit called the transaxle,
which connects directly to provide
power to the drive wheels.
•The drive wheels turn and push the
vehicle forward (or backward), and
off you go. 21
BAJA SAE IITK : Basics of Automobile – Rohit Arora
FUNDAMENTALS
The complete vehicle is traditionally divided into
three groups:
Powertrain
Chassis/suspension
Body.
The power train contains elements which propel
the vehicle, the body provides room for people
and cargo, and the chassis and suspension allow
the vehicle to ride, turn, and stop.
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
FUNDAMENTALS
Modern vehicles integrate the body and chassis
into a structure known as unibody or monocoque.
A chassis is a structure, usually a ladder
framework, able to carry on all the remaining
components of the vehicle.
The suspensions is for the mechanical linkage of
wheels with the framework.
The steering system is for changing wheel angles
according to vehicle path.
The brake system is for reducing speed or
stopping the vehicle.
The transmission is for applying engine torque to
the driving wheels.
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
FORCES INVOLVED
The forces exchanged with the ground can be
classified as:
• Forces perpendicular to the ground (vertical
for the motion on a plane road); in steady state
conditions these forces can be considered constant,
but because of obstacles on the road, they are
variable; they are a factor in passenger comfort.
• Longitudinal forces; these are primarily due to
propulsion (engine and transmission) and braking
systems; they are relevant to vehicle speed control.
• Transversal forces; these are due to wheel
steering angles, and they are relevant to road holding
and stability. 25
BAJA SAE IITK : Basics of Automobile – Rohit Arora
DESIGN TARGET FOR BAJA 2012
1. Maximum speed – 60 km/hr
2. Weight of vehicle – 270 kg
3. Ground clearance – 20 cm or 8 inch
4. Track width – 140 cm or 56 inch approx
5. Wheel base – 130 cm or 52 inch approx
6. Braking distance – 1400 cm
7. Turning radius – 240 cm or 96 inch
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
CHASSIS
•Automotive chassis is considered to be one of the significant
structures of an automobile.
•It is usually made of a steel frame, which holds the body and motor of
an automotive vehicle.
•More precisely, automotive chassis or automobile chassis is a skeletal
frame on which various mechanical parts like engine,
tires, axle assemblies; brakes, steering etc are bolted.
• Ideally, the purpose of a motor car chassis is to connect all four
wheels with a structure which is rigid in bending and torsion-that is
one which will neither sag nor twist.
•It must be capable of supporting all components and occupants and
should absorb all loads fed into it without deflecting unduly.
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
CHASSIS
Considering the chassis in this way, its chief purpose is to provide
suitable mountings for all components of the car.
In descending order of magnitude, the major loads involved are:
I. rear suspension and final drive 5. seats (and occupants), steering
column, pedals and other controls,
including hydraulic cylinders
2. front suspension and steering 6. radiator
3. engine and/or gearbox 7. battery
4. fuel tank 8. spare wheel
It is the layout of these components which largely decides the design of
the chassis and in the early stages of planning the greatest attention
should be given to front and rear suspension pick-ups, which must be
catered for as point loads in the structure.
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
CHASSIS
•In connection with the front suspension, the number of point loads,
their magnitude and direction, depends on the type of suspension
employed.
•Rear suspension loads are basically similar but generally of a
higher order, owing to the greater weight normally concentrated
on the rear wheels and the fact that the rear suspension normally
has to accommodate driving torque.
•Automobile chassis is usually made of light sheet metal or composite
plastics. It provides strength needed for supporting vehicular
components and payload placed upon it.
•Automotive chassis or automobile chassis helps keep an automobile
rigid, stiff and unbending. Auto chassis ensures low levels of noise,
vibrations and harshness throughout the automobile.
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
ROLL CAGE
•A roll cage is a safety feature installed in a vehicle used in
environments where there is a high danger of rolling.
•The idea behind a roll cage is that if the vehicle rolls, it will
protect the occupants.
• While parts of the vehicle may be damaged or crushed,
the roll cage prevents intrusion into the passenger compartment,
creating a safe pocket.
•In addition to a cage, it is also possible to see a roll bar, placed
behind the driver's head to offer protection. This feature should
not be confused with a sway or stabilization bar which is used to
stabilize a vehicle to prevent rolling. Sway bars are also common
features on vehicles used at high speeds.
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
In order to optimized the strength,
durability and weight of Chassis FEA
will be used to analyze the chassis for
all six loading condition.
The six analysis tests conditions
are
front impact, side impact, rollover
impact, heave and the loading on the
frame from the front and rear shocks
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
ENGINE AND TRANSMISSION
A quick look at the engine:
Power - 8 kW at 4400 rpm
Max Torque – 19 Nm at 3000 rpm
•As Engine will be given to us. Thus we will have a little choice
while working on engine.
•Configuration of our vehicle would be rear engine rear wheel
drive.
•We decided to keep the maximum speed of the vehicle at 60
km/hr as the vehicle is not about larger speed but greater torque
and stability.
•As per the rules of the competition, the engine cannot be
modified in any way. This restriction causes the design
emphasis to be placed on the choice of transmission.
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
RR PATTERN :
Rear engined cars are almost always
rear wheel drive, a layout known as RR.
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
RR PATTERN :
•In automobile design, a rear-
engine design layout places
the engine at the rear of the
vehicle.
•The center of gravity of the
engine itself is past the rear
axle.
•This is not to be confused
with the center of gravity of
the whole vehicle, as an
imbalance of such proportions
would make it impossible to
keep the front wheels on the
ground.
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
MULTIBODY SYSTEMS
A multibody system is used to model the dynamic behavior of
interconnected rigid or flexible bodies, each of which may
undergo large translational and rotational displacements.
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
Multibody Systems Simulation Software
•There exists a range of commercial computer packages that can be used
to solve problems in multibody systems analysis. Here I will use
MSC.ADAMS to understand vehicle dynamics.
• The main use of MSC.ADAMS within the automotive industry is to
simulate the performance of subsystems and full vehicles.
• The analyst will often wish to validate the performance of say a
suspension model over a range of displacements between full bump to
rebound before sending vehicle to production.
• A detailed model may include representations of the body, sub frames,
suspension arms, struts, anti-roll bars, steering system, engine, drive
train and tires.
• This software can link or interface with CAD systems, finite element
programs, software used for advanced visualization or additional
software modules such as those used for tyre modeling.
• The combined use of these systems can lead to the development of what
may be referred to as virtual prototypes that is computer models that can
simulate the tests and conditions that a real prototype would be subject
to during the development of a new engineering product. 36
BAJA SAE IITK : Basics of Automobile – Rohit Arora
Thank You !!!
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BAJA SAE IITK : Basics of Automobile – Rohit Arora
