1. The document provides information on the basic parts and functioning of an automobile, including the engine, chassis, body, and other structural components. It describes the engine components like the cylinder, piston, crankshaft, and others. 2. It also discusses the different types of chassis used in automobiles like the ladder chassis, tubular chassis, and monocoque chassis. The functions of the chassis include supporting the vehicle body and providing mounting locations for other parts. 3. Additionally, it summarizes the purpose and components of the internal combustion engine, which generates power through the combustion of fuel and provides it to the transmission system to power the wheels.

1. Unit- I
Vehicle Structures and Engines
R18A0331

2. Automobile Engineering
An automobile is self propelled vehicle driven by a internal
combustion engine and used for transportation of passenger and goods
on ground.
Eg: Buses, Car, Trucks, tractor, scooter
The basic parts of an automobile consists of “chassis of a body”,
“power developing and transmission units”, “tyres and wheels”,
An engine develop the power through delivered to the wheels trough
transmission units through clutch or fluid coupling.

3. History of an Automobile

5. Automobile in INDIA

6. Classification of an Automobile

11. Major Parts of an Automobile

12. • Chassis include the following
• Frame
• Springs and Shock absorbers
• Steering System
• Brakes
• Tyres and Wheels
• Transmission Units includes
• Clutches
• Gear box
• Universal Joint
• Final Drive
• Axle and Differential
• Engine Units Includes
Full System
Ignition System
Lubricating System
Cooling system
• Electrical System Includes
Battery
Dynamometre
Alternators
Iginition Starting and Lighting

13. Description of an Automobile
• Type: Motor Cycle, Car, Bus, truck, etc.,
• Capacity: Tonnage and no. of seats
• Make: Manufacturer of the vechile and Engine Capacity
• Drive: Left hand Drive or Right hand Drive, 2, 4, 6 wheel
drive
• Model: Year of Manufacturing

14. Frame
The frame is the skeleton of the vehicle. It servers as a
main foundation and base for alignment for the chassis.
Types of Frames
Conventional frame,
Semi integral frame,
Integral or untidiest frame.
An automobile is made up of mainly two units, these are Chassis and Body.
“Frame” + “Base components” = “Chassis”
“Chassis” + “Body” = “Vehicle”

15. Chassis
If the frame contains the base components its called as
chassis.
The components are like Engine, radiator, clutch,
gearbox, silencer, road wheels, fuel tank, wirings,
differential units, etc..,
Body
Body is the superstructure of the vehicle and it is
bolted to the chasis.

16. Layout of an Automobile
• Front Engine Rear Wheel Drive
• Front Engine Front Wheel Drive
• Rear Engine Rear Wheel Drive
• Four Wheel Drive (All Wheel Drive)
• Articulated Vehicle
• Heavy Commercial Vehicles
• Rigid Vehicles

17. Front Engine Rear Wheel Drive

19. Rear Engine Rear Wheel Drive

21. Front Engine Front Wheel Drive

22. Advantages Disadvantages

23. Four Wheel Drive (All Wheel Drive)

25. Frame

26. Types of Frames

27. Conventional frame

28. Integral Frame
In this type of construction, there is no frame. It is also called
unitized frame-body construction.
All the assembly units are attached to the body and all the functions
of the frame carried out by the body itself.
Here the body shell and underbody are welded into single unit. The
underbody is made of floor plates and channel and box sections
welded into single unit. This assembly replaces the frame.
This frame is used now a days in most of the cars. Due to elimination
of long frame it is cheaper and due to less weight most economical
also.
The main disadvantage is repairing

29. Semi Integral Frame
• In some vehicles half frame is fixed in the front end on
which engine gear box and front suspension is
mounted.
• In this case the rubber mountings used in conventional
frame between frame and suspension are replaced by
more stiff mountings.
• Because of this some of the vehicle load is shared by
the frame also. This type of frame is heavier in
construction.
• It has the advantage when the vehicle is met with
accident the front frame can be taken easily to replace
the damaged chassis frame.
• This type of frame is used in some of the European and
American cars.

30. Chasis
• It bears all the stresses on the vehicle in both static and dynamic conditions. In
a vehicle, it is analogous to the skeleton of a living organism.
• FUNCTIONS OF A CHASSIS
1. Supports or bears the load of the vehicle body.
2. Provide the space and mounting location for various aggregates of vehicle.
3. Supports the weight of various systems of the vehicle such
as engine, transmission etc.
4. Supports a load of passengers as well as the luggage.
5. Withstands the stresses arising due to bad road conditions.
6. Withstands stresses during braking and acceleration of the vehicle.

31. Types of Chassis
• Ladder Chassis
• Tubular chassis
• Monocoque Chassis

32. Ladder chassis
• The ladder-frame chassis is one of the oldest
chassis types. This chassis is characterised by two
long heavy beams that are supported by two
smaller ones. Its quality of being easily
manufactured not only made it contemporarily
popular but also eased the way for its mass
production. Since ladder frame chassis is
significantly heavy it’s usually used for vehicles
that transport heavy material.
Benefits
Easy to manufacture and easy assembling of the car over it.·
Heavy and strong tensile strength.
Drawbacks
Poor cornering ability due to weak torsional rigidity
Its heaviness doesn’t make it suitable for performance cars and hatchbacks.

33. Tubular Chassis
• Tubular space frame chassis employs dozens of circular-section
tubes (some may use square-section tubes for easier connection
to the body panels, though circular section provides the
maximum strength), position in different directions to provide
mechanical strength against forces from anywhere.
• This type of chassis is mostly used while manufacturing racing
cars due to the enhanced safety they offer.
Benefits
Its crafting allows better contact between the half axle and ground making it preferable for off-roading.
A cylindrical tube covering the driveshaft saves it from any damage while off-roading.
The structure’s torsional toughness is relatively more supple than ladder chassis.
Drawbacks
In case the driveshaft fails, the whole chassis needs to be dismantled as the driveshaft is covered with the
cylindrical tube of the chassis.
The manufacture of backbone chassis is costly and increases the overall cost of the car.

34. Monocoque Chassis
• The construction of a monocoque chassis is
quite simple in the sense that the entire
structure is one big construction.
• All components or mechanical parts constitute
the frame, foundation and body of the car.
• The engine, gearbox, suspension, seats and
exterior body panels are simply attached to the
construction. This means that the overall
construction is very lightweight and compact.
There is quite a lot of safety element to it.
• The applications include all sorts of everyday
vehicles ranging from small and compact
hatchbacks to large and heavy SUVs. It must
be noted that modern SUVs are using
monocoque construction quite a bit which was
not always the case in the past.
Benefits
• It’s safer than both the other chassis due
to its cage-like construction.
• The chassis is easy to repair as well.
• It has superior torsional rigidity.
Drawbacks
• The chassis is obviously heavy as it’s
both the frame and chassis as one
single entity.
• Producing it in small quantities is not
financially feasible and thus it
cannot be used for cars that are not
mass-produced.

35. Body of an Automobile
• Body is the super-structure for all vehicles. It may
either be constructed separately and bolted to the
chassis or manufactured integral with the chassis (i.e.
Frameless construction).
• The chassis and the body make the complete vehicle.
• A body consists of windows and doors, engine cover,
roof, luggage cover etc. The electrical system in the
body is connected to the chassis electrical units so that
the battery and the generator/altenator can furnish the
required electrical energy to the system.
Types of Body
1.Car
2. Straight truck
3. Truck-half body
4. Truck-platform type
5. Tractor
6. Tractor with articulated trailer
7. Tanker
8. Dumper truck
9. Delivery van
10. Station wagon
11. Pick-up
12. Jeep
13. Buses
14. Mini-buses
15. Three wheeler

37. Vehicle Aerodynamics
The term “Aero” means air, “Dynamic” means motion. Therefore,
aerodynamic is the study of effects of the wind on the vehicle in motion.
When the vehicle is moving the air flow is dependent on the two factors.
• Vehicle speed.
• Ambient wind.
Advantages of Aerodynamics
• More Fuel Efficiency
• Higher Speeds
• Good Aesthetic and Stylish Appearance
• More Stability of car at high Speed
• Reduce Noise Level

38. • A moving vechile is opposed by various forces, known as resistance
• For moving the vechile, the driving force (F) should be equal to the sum of all resistance
forces applied on it.
• When ‘F’ exceeds the sum of all resistance forces, vechile accelarate
• When ‘F’ less than the sum of all resistance forces, vechile deaccelarate
• Air Resistance: This is the resistance offered by air to the movement of a vehicle. The air resistance
has an influence on the performance, ride and stability of the vehicle and depends upon the size and
shape of the body of the vehicle, its speed and the wind velocity. The last term should be taken into
account when indicated, otherwise it can be neglected. Hence in general, air resistance,

39. • Rolling Resistance: The magnitude of rolling resistance depends mainly on
– the nature of road surface,
– the types of tyre viz. pneumatic or solid rubber type,
– the weight of the vehicle, and
– the speed of the vehicle.
Gradient Resistance: The resistance due to steepness of the road gradient. It depends upon the weight of
the vehicle and road gradient. It does not depend upon vehicle speed.

41. • FORCES ACTING ON VEHICLE :
Drag force (Fx)- Along the vehicle direction Profile drag, interference
drag, skin friction, cooling and ventilation system drag.
Cross wind (Fy)- along side or lateral direction Asymmetric flow of air
around the vehicle body.
Lift force(Fz) – vertical force acting from the bottom of the vehicle.
Because of pressure difference between top and bottom of the vehicle.
• MOMENTS DUE TO FORCES:
Moments created by forces acting on the vehicle
Pitching moment – Created by drag or lift force about y-axis and
reduces the traction in the wheels
Yawing moment- Created by cross wind about z-axis
Rolling Moment – Created by cross wind about x-axis

42. I.C Engine
• Combustion of a fuel with oxygen of the air
occurs with in the cylinder of the engine. The
engine gains it energy from the heat generated
during combustion by fuel and oxygen.
• Lighter liquid fuel or spirit are petrol engines.
• Heavier Liquid fuels are Diesel engines.

43. Advantages of IC engine Components of IC Engine
• Over all Efficiency is High
• Greater Mechanical
simplicity
• Weight to power ratios is
generally low
• Lower initial cost
• Easy to start from cold
conditions
• Required low space to
construct
• Cylinder and Cylinder Head
• Piston
• Piston Rings and Pins
• Connecting rod
• Crank and Crank shaft
• Fly wheel
• Governor
• Camshaft
• Spark Plug
• Carburetor or Injector

45. Cylindrical Block
• It is a container fitted with a piston, where the fuel is burnt and power
is produced.
• Cylinder is the main body of the IC engine. Cylinder is a part in
which the intake of fuel, compression of fuel and burning of fuel take
place. The main function of the cylinder is to guide the piston.
• For cooling of the cylinder a water jacket (for liquid cooling used in
most cars) or fin (for air cooling used in most of the bikes) is situated
at the outer side of the cylinder.
• At the upper end of the cylinder, the cylinder head and at the bottom
end crankcase is bolted.
• Material: Ductile (Nodular) Cast Iron,30C8 (Low Carbon Steel)
• Manufacturing method: Casting, Forging and after that heat
transfer, Machining

46. Cylinder Head/Cylinder Cover
• One end of the cylinder is closed utilizing a cylinder head. This
consists of an inlet valve for admitting air-fuel mixture and
exhaust valve for removing the products of combustion.
• The inlet valve, exhaust valve, spark plug, injector, etc. are
bolted on the cylinder head. The main function of the cylinder
head is to seal the cylinder block and not to permit entry and
exit of gases on the cover head valve engine.
• Function: It provides the housing for exhaust and intake valves,
threaded holes for the spark plugs or fuel injector and
necessary linkages, passage for cooling jackets and passages for
the fuel and air mixture.
• Material: Aluminium alloys
• Manufacturing Method: Casting, Pressure Die Casting,
forming.

47. Piston
• Piston is used to reciprocate inside
the cylinder.
• It transmits the energy to the
crankshaft through the connecting
rod.
• Material: Aluminum Alloy 4652
because of its Low Specific Gravity.
• Manufacturing Method: Casting

48. Piston Rings
• These are used to maintain a pressure-tight seal between the
piston and cylinder walls and also it transfers the heat from
the piston head to cylinder walls.
• These rings are fitted in grooves that have been cut in the
piston. They are split at one end so they can expand or
slipped over the end of the piston.
• Function of Piston rings:
1. To provide a pressure seal to prevent blow-by of burnt
gases.
2. To form the main path for conduction of heat from the
piston crown to the cylinder walls.
• Material: cast iron of fine grain and high elastic material
• Manufacturing Method: Pot casting method

49. Gudgon Pin or Piston Pin
• These are hardened steel parallel
spindles fitted through the piston
bosses and the small end bushes or
eyes to allow the connecting rods to
swivel. It connects the piston to the
connecting rod. It is made hollow for
lightness.
• Material: Plain Carbon steel 10C4

50. Connecting Rod
• One end of the connecting rod is connected to the piston
through a piston pin while the other is connected to
crank through a crank pin.
• It transmits the reciprocatory motion of the piston to the
rotary crank.
• There are two ends of connecting rod one is known as
the big end and other as small end. The big end is
connected to the crankshaft and the small end is
connected to the piston by use of piston pin.
• Function :
1) It converts the reciprocating motion of the piston into
rotary motion of crankshaft.
2) It connects piston to the crankshaft.
• Material: Low Carbon steel 30C8
• Manufacturing Methods: Forging and after that heat
treatment.

51. Crank Shaft
• The function of the crankshaft is to transform reciprocating
motion into a rotary motion.
• The crankshaft of an internal combustion engine receives the
efforts or thrust supplied by the piston to the connecting rod
and converts the reciprocating motion of the piston into
rotary motion of the crankshaft.
• The crankshaft mounts in bearing so it can rotate freely.
• The shape and size of crankshaft depends on the number and
arrangement of cylinders.
• Functions: 1. It converts the reciprocating motion to the
rotating motion.
2. It transmits Power to the Flywheel.
3. It receives Power from flywheel.
• Material: 37C15 Alloy Steel.
• Manufacturing Method: Forging

52. Fly Wheel
• The flywheel is a rotating mass used as an energy storing
device.A flywheel is secured on the crankshaft. The main
function of the flywheel is to rotate the shaft during the
preparatory stroke. It also makes crankshaft rotation more
uniform.
• Function :
1. Flywheel absorbs energy during power stroke and supplies it
during remaining strokes.
2. Flywheel keeps the crankshaft rotating at the uniform speed
throughout in spite of Uneven power impulses of engine cylinders.
3. Flywheel carries the drive from the starting motors to crankshaft
while the starting the Engine.
• Material: cast Iron
• Manufacturing Method: Casting

53. Crank Case
• It supports and covers the cylinder and
the crankshaft. It is used to store the
lubricating oil.
• The main body of the engine to which
the cylinder is attached and which
contains the crankshaft and crankshaft
bearing is called crankcase. It serves as
the lubricating system too and sometimes
it is called oil sump. All the oil for
lubrication is placed in it.

54. Governor
• A device for regulating automatically output
of a machine by regulating the supply of
working fluid.
• When the speed decreases due to an increase
in load the supply valve is opened by a
mechanism operated by the governor and the
engine, therefore, speeds up again to its
original speed.
• Thus the function of a governor is to control
the fluctuations of engine speed due to
changes in load.

55. Carburator
• The function of a carburetor is
to atomize and meter the liquid
fuel and mix it with the air as it
enters the induction system of the
engine.
• Maintaining fuel-air proportion
under all conditions of operation
appropriate to the conditions.

56. Spark Plug
• The main function of a sparkplug is to conduct the high
potential from the ignition system into the combustion chamber.
• It provides the proper gap across which spark is produced by
applying high voltage, to ignite the mixture in the ignition
chamber.
• Manufacturing Method: Each major element of the spark
plug—the center electrode, the side electrode, the insulator, and
the shell—is manufactured in a continuous in-line assembly
process. Then, the side electrode is attached to the shell and the
center electrode is fitted inside the insulator. Finally, the major
parts are assembled into a single unit.

57. Injector or Fuel Atomiser
• Fuel injection is a system for mixing fuel with air in an internal combustion
engine. It has become the primary fuel delivery system used in
automotive petrol engines, having almost completely replaced carburetors
in the late 1980s.
• The primary difference between carburetors and fuel injection is that fuel
injection atomizes the fuel by forcibly pumping it through a small nozzle
under high pressure, while a carburetor relies on low pressure created by
intake air rushing through it to add the fuel to the airstream.
• The fuel injector is only a nozzle and a valve: the power to inject the fuel
comes from a pump or a pressure container farther back in the fuel supply.

58. Variable Valve Timing (VVT)

59. Variable valve Timing