This document discusses vehicle structure and engines. It begins by describing different types of automobiles based on purpose, weight, fuel used, passenger capacity, number of wheels, and driver seat location. It then covers vehicle construction, including chassis classification based on engine location and number of wheels. Frame construction and materials are explained. The components of an automobile engine are defined, including the cylinder block, cylinder liners, piston, connecting rod, piston rings, crankshaft, camshaft, and valves. The document concludes by classifying internal combustion engines and discussing valve timing and variable valve timing.

1. AUTOMOBILE ENGINEERING
ME6602

2. UNIT-I
VEHICLE STRUCTURE AND ENGINES

3. • UNIT I VEHICLE STRUCTURE AND ENGINES
Types of automobiles, vehicle construction
and different layouts, chassis, frame and body,
Vehicle aerodynamics(various resistances and
moments involved), IC engines –components
functions and materials, variable valve timing
(VVT).

4. TYPES OF AUTOMOBILES

5. TYPES OF AUTOMOBILES
• (i) with respect to the purpose
• (a) Passenger vehicles. Ex. Car, bus, jeep, scooter, mopeds and motor
cycles
• (b) Goods carriers: ex. Trucks and lorries
• (ii) weight of the vehicles:
• - Heavy weight vehicle- buses, trucks and trailers
• - Light weight vehicles - cars, jeeps
• - Medium weigh vehicles – minibus and station wagon
• (iii) With respect to the fuel:
• - Petrol vehicles – scooters, cars motors cycles
• - Diesel vehicles - Buses , trucks
• Gas vehicles – Coal gas, LPG, CNG vehicles
• Electric vehicle – Heavy cranes, battery truck, cars and fork lifts
• Solar vehicles.

6. • (iv) with respect to capacity:
• Heavy transport vehicles – Bus lorries, trucks, tractors
• Light transport vehicles _ Car, scooter, mopeds, motor
cycles, jeeps
• (v) with respect to number of wheels:
• Two wheelers – Scooters, mopeds
• Four wheelers – car, jeep, buses, truckes
• Three wheelers – Auto, tempos
• Six wheelers - heavy trucks
• (vi) With respect to side of driver seat
• - Left hand drive- American, European and UAE
• -Right hand drive – Indian vehicles

7. • Bullock cart consists of
• (i) Frame (ii) wheels & axle
• (iii) Yoke (iv) Body or superstructure and
platform
• These pars can be divided into two main
portions
• (i) Machine portion (ii)carriage portion

9. VEHICLE CONSTRUCTION

10. VEHICLE CONSTRUCTION

11. Classification of chassis
• According to the fitting of engine
1.Full-forward – Cars, mahindra jeeps
2.Semi-forward – Tata series of vehicle
3. Bus chassis
4. Engine at back -volkswagen cars, layland bus of
england.
5. Engine at centre.-royal tiger world master buses of
Delhi transport.
• According to the number of wheels fitted in the wheels
1.4x2 drive chassis 2. 4x4 drive chassis
3. 6x2 drive chassis 4. 6x4 drive chassis

12. LAYOUT OF CHASSIS

13. CLASSIFICATION OF CHASSIS
According to the fitting of engine

14. Characteristics of Good Chassis
• Fast pickup
• Strength
• Safety
• Durability
• Ease of control
• Speed
• Power accessibility
• Economy of operation
• Low centre of gravity
• Stability
• Load clearance
• Braking ability
• Simplicity of lubrication

15. FRAME
• Main part of the chassis
• Backbone of the vehicle.
Functions of the frame
• To form the base for mounting engine & transmission
systems
• To withstand the engine & transmission thrust & torque
stresses as well as accelerating and braking torque
• To accommodate suspension system
• To carry the other parts of the vehicle & its passengers
• To resist the effect of centrifugal forces when cornering
a curve
• To with stand bending and twisting stresses

16. FRAME CONSTRUCTION

17. Materials for Frame
 Mild steel sheet, Carbon steel sheet and
Nickel alloy steel sheet
The composition of Nickel alloy steel sheet
• Carbon - 0.25 to 0.35%
• Manganese – 0.35 to 0.75%
• Silicon – 0.30% (maximum)
• Nickel – 3%
• Phosphorus – 0.05% (max)
• Sulphur – 0.5% (max)

18. FRAMELESS CONSTRUCTION

19. TYPES OF VEHICLE BODY

20. COMPONENTS OF CAR BODY

21. RESISTANCES TO VEHICLE MOTION
1. Air resistance:
a. Size of vehicle b. Shape
c. Speed d. Wind velocity
2.Gradient resistances:
The component of the vehicle’s weight which is
parallel to the plane of the road. This component
remains constant but independent of the vehicle
speed.
3. Miscellaneous resistance:
a. Road characteristics b. Tyre characteristics
c. Vehicle weight d. Vehicle speed

22. AERODYNAMICS OF AUTOMOBILE
BODY
i) Drag force(Fx)
ii) Lift force(Fz)
iii) Cross wind force(Fy)

23. ENGINE CONSTRUCTION

24. CYLINDER BLOCK
 Cylinder block materials – Grey cast iron, aluminium with steel sleeves
 Cylinder head materials – cast iron, aluminium alloy etc.

25. CYLINDER LINERS
 chromium plated mild steel tubes

26. PISTON
 Cast iron, aluminium alloy, chrome – nickel alloy, nickel –
iron alloy and cast steel

27. CONNECTING ROD
 Plain carbon steel, aluminium alloy and nickel alloy steels

28. PISTON RINGS
Cast iron, alloy cast iron containing silicon and manganese, alloy
steels etc.
•piston rings are generally coated with chromium or cadmium.

29. CRANK SHAFT
 carbon steel, nickel-chromium and other heat treated alloy
steels.

30. CAM SHAFT

31. VALVES
It should be made of high heat resistance material such as
silicon-chrome steel, high speed steel, cobalt-chrome steel and
tungsten steel.

32. SIDE VALVE MECHANISM

33. OVERHEAD VALVE MECHANISM

34. CLASSIFICATION OF IC ENGINES

35. CLASSIFICATION OF IC ENGINES

36. Theoretical Valve Timing Diagram for
Four Stroke SI Engines

37. Actual Valve Timing Diagram for Four
Stroke SI Engines

38. Variable Valve Timing (VVT) for Four
Cylinder Engine