Introduction about Automobile Engineering

1. AUTOMOBILE ENGINEERING
ME 8091

2. UNIT-I
VEHICLE STRUCTURE AND ENGINES

3. TYPES OF AUTOMOBILES

4. VEHICLE CONSTRUCTION

5. VEHICLE CONSTRUCTION

6. LAYOUT OF CHASSIS

7. CLASSIFICATION OF CHASSIS
According to the fitting of engine

8. FRAME
• The frame is the main part of a chassis. It is
the backbone of the vehicle. All other parts of
the chassis are mounted on the frame. It is a
rigid structure which forms a skeleton to hold
all major parts together.

9. FRAME CONSTRUCTION

10. 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)

11. TYPES OF FRAME
1. CONVENTIONAL FRAME CONSTRUCTION
2. SEMI-INTEGRAL FRAME CONSTRUCTION
3. INTEGRAL OR FRAMELESS CONSTRUCTION

12. FRAMELESS CONSTRUCTION

13. Loads on chassis frame
1. Loads of short duration
2. Combined loads of momentary duration
3. Inertia loads
4. Impact loads
5. Load due to road camber
6. Load due to wheel impact
7. Static loads
8. overloads

14. DEFECTS IN FRAME
1. Misalignment in horizontal and vertical plane
2. Twisting of main frame and sub-frames
3. Buckled main frame and sub-frames
4. Bent side members and dumb iron
5. Broken or loose gusset plates and rivets

15. TYPES OF VEHICLE BODY

16. Body construction and its components
a). Structure: All load carrying elements are
defined as structure.
b). Finish: This group includes all unstressed
units such as bonnet, boot, lid, bumper etc.
c). Equipment: This group includes various parts
such as rim, seats, doors, window etc.

17. COMPONENTS OF CAR BODY

18. 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

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

20. Drag force(Fx)
FX = CX ρv2A/2
Where
CX= drag coefficient
ρ= density of air
V= velocity of air
A = projected area of the vehicle viewed
from front

21. Lift force(Fz)
Fz = Cz ρv2A/2
Where
Cz= lift coefficient
ρ= density of air
V= velocity of air
A = projected area of the vehicle viewed
from front

22. Cross wind force(Fy)
• Pitching moment(MY): Is caused by the drag
force or lift force about y axis. This moment
makes the rear wheels lift off from the ground
and further it reduces the available traction.
• Yawing moment(Mz): Is caused by the cross
wind force (Fy) about Z.
• Rolling moment(My): is caused by the cross
wind force (Fy) about Z.

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
Chilled cast iron, forged steel, grey cast iron, nickel steel

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

39. Variable Valve Timing (VVT) for Four
Cylinder Engine
i). Slow engine speeds
ii). High engine speeds
iii). Valve opening period

40. Types of variable valve timing
1. Cam changing VVT
2. Cam phasing VVT
3. Combined cam changing and cam phasing
VVT