Vehicle Structure and Engines

In this PPT, the vehicle structure and Engines are discussed.

1. AUTOMOBILE ENGINEERING ME8091

2. UNIT-I VEHICLE STRUCTURE AND ENGINES

3. TYPES OF AUTOMOBILES

4. VEHICLE CONSTRUCTION

5. VEHICLE CONSTRUCTION

6. Different Parts of IC Engine Cylinder. Cylinder Head. Piston. Piston Rings. Gudgeon Pin. Connecting Rod. Crankshaft. Flywheel.

7. Different Parts of IC Engine Parts only Petrol Engine has- Spark Plug. Carburettor . Fuel Pump. Parts only Diesel Engine has Fuel Pump. Fuel Injector

8. Cylinder-

9. CYLINDER Cylinder contains gas under pressure and guides the piston. The ideal form of a Plain Cylindrical Barrel in which the piston slides. The Cylinder is made of hard grade cast iron and usually made up of cast in one piece.

10. Cylinder Head-

11. Cylinder Head One End of the Cylinder head is closed by means of a removable cylinder head. Which usually contains the inlet or admission valve for admitting the mixture of air and fuel, also the exhaust valve which scavenges the exhaust gas.

12. Valve Mechanism

13. Piston

14. Piston Ring

15. PISTON RING To provide a good sealing fit between the piston and cylinder, piston is equipped with piston rings. The rings are usually made of cast iron of fine grains and high elasticity which will not affected by the working heat. Some rings are made of alloy Spring steel.

16. PISTON RINGS

17. Gudgeon Pin or Piston ring

18. Gudgeon pin They are made up of Hardened steel parallel spindle fitted through the piston bosses and the Small end bushes or eyes to allow the connecting rods to swivel. Gudgeon pins are a press fit in the piston bosses of light alloy piston when cold

19. Crankshafts Crank shaft of an IC Engine receives via its cranks the efforts supplied by the pistons to the connecting rods. It is usually made up of steel forging. But some makers use special type of Cast iron such as Spheroidal Graphite or Nickel Alloy Casting which are Cheaper to produce and have good service.

20. Crankshaft

21. Flywheel A flywheel (Steel or Cast iron Disc) secured on the crank shaft performs the following function- Bring the mechanism out of dead centres . Stores energy required to rotate the shaft during preparatory strokes. Makes crankshaft rotation more uniform.

22. Flywheel

23. Chassis To construct any automobile, Chassis is the basic requirement. Chassis is the backbone of the vehicle. It is the mounting of all the components including the body. It is also called as carrying unit.

24. LAYOUT OF CHASSIS

25. CLASSIFICATION OF CHASSIS According to the fitting of engine

26. Main component of Chassis Frame. Front suspension. Steering Mechanism. Engine, Clutch and Gear Box. Radiator. Wheels. Propeller Shaft. Differential Units

27. Main Component of Chassis Clutch. Gear Box. Front Axle. Rear Axle

28. FRAME The Frame is the foundation for carrying the Engine and body of the Vehicle. It is also carries steering, power trains. When the Engine, Wheels, Power trains, Brackets and Steering system are fitted on the frame, the assembly is known as Chassis.

29. FRAME CONSTRUCTION

30. 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)

31. TYPES OF FRAME CONVENTIONAL FRAME CONSTRUCTION SEMI-INTEGRAL FRAME CONSTRUCTION INTEGRAL OR FRAMELESS CONSTRUCTION

32. Conventional Frame It is also Known as Non-Load Carrying Frame, here the load on the Vehicles are transferred to the Suspension. These type of Frame is not suited for resist torsion It mostly uses Channel Section, Tubular Section and Box Section.

33. Integral Frame or frameless This frame is used now a days in most of the cars, there is no frame and all the assembly units are attached to the body. In this construction there is no frame and all assembly units are attached to the body. They are assemble by using large number of mild steel pressing

34. FRAMELESS CONSTRUCTION

35. Semi Integral Frame In some Vehicle half Frame is fixed in the front end on which engine gear box and front suspension is mounted. This types of frame load will be transferred to the body. The frame however is heavy.

36. Semi Integral Frame

37. Loads on chassis frame Loads of short duration Combined loads of momentary duration Inertia loads Impact loads Load due to road camber Load due to wheel impact Static loads overloads

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

39. Automobile Body Body is the super structure for all vehicles. It may either be constructed separately and bolted or manufactured integral with chassis. A body consist of windows, Doors, Engine Cover, roof, Luggage cover etc., The 60 to 70 % of the vehicle weight is contributed by the Body.

40. Type of Body Car. Straight truck. Truck-Half Body. Truck-Platform. Tractor. Tractor with articulator trailer. Tanker. Dumper Truck.

41. Types of body

42. COMPONENTS OF CAR BODY

43. 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.

44. Floor assembly of a car

45. Materials for Body Construction The Material used for Construction parts of the body are- Wood, Plastics, Toughened glass and Aluminum. Wooden bodies requires a separate sheet chassis frame to carry the load. It has low life span and initial cost is high.

46. Working of four stroke petrol Engine

47. Working of four stroke Diesel Engine

48. Working of Four stroke Engine Various stroke in IC Engine- Suction or Induction Stroke. Compression stroke. Power Stroke or Expansion stroke. Exhaust Stroke.

49. Working of Two Stroke Engine

50. Vehicle Aerodynamics Automotive Aerodynamics is the study of the aerodynamics of road Vehicles. Its main goals are reducing drag and wind noise, Minimizing noise emission and preventing undesired lift force other cause of aerodynamics Instability at high speeds. It is important to produce downforce to improve traction and thus cornering abilities.

51. Types of resistance caused to vehicle Broadly the resistance can be categorized into following categories- Air Resistance. Gradient Resistance. Rolling Resistance. Inertia Force.

52. RESISTANCES TO VEHICLE MOTION 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

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

54. Drag force( Fx ) F X = C X ρv 2 A/2 Where C X= drag coefficient ρ= density of air V= velocity of air A = projected area of the vehicle viewed from front

55. Lift force( Fz ) F z = C z ρv 2 A/2 Where C z = lift coefficient ρ= density of air V= velocity of air A = projected area of the vehicle viewed from front

56. Cross wind force( Fy ) Pitching moment (M Y ): 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( M z ): Is caused by the cross wind force ( Fy ) about Z. Rolling moment(M y ): is caused by the cross wind force ( Fy ) about Z .

57. Valve Timing Diagram

58. SIDE VALVE MECHANISM

59. OVERHEAD VALVE MECHANISM

60. Cut section of Engine

61. Theoretical Valve Timing Diagram for Four Stroke SI Engines

62. Actual Valve Timing Diagram for Four Stroke Petrol Engines

63. Actual Valve Timing Diagram for Diesel Engine

64. Variable Valve Timing Diagram The variable valve timing system alter the valve timing suits engine speed and load conditions. Although system condition. A petrol Engine has to operate at varying engine speeds from idle, typically 750rpm, through the high speed up to 7500 rpm and above .

65. Variable valve timing Variable valve timing optimizes the over lap caused by the varying speed. VVT e nable good torque to be achieved over the whole engine speed range but the added benefit of valve overlap is to facilitate the mixing of some exhaust gas with the fresh charge of air.

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

67. Variable valve timing Slow Engine- If the Inlet Valve timing is to altered so that it is retarded or opened late all of the exhaust gases so the cylinder will be filled with fresh and uncontaminated mixture.

68. Variable Valve Timing High Engine Speed- At the high Engine speed, The fresh mixture can be drawn into cylinder by the depression caused by the flow of exhaust gas through the exhaust valve.

69. Variable Valve Timing Valve Opening Period- Engine in low speed, the valve opening period allows fresh charge. Engine high Speed, the Valve Lift timing is Increased, as a result there is increase in the engine power.

70. Types of variable valve timing Cam changing VVT Cam phasing VVT Combined cam changing and cam phasing VVT

71. Cam Changing This type of VVT uses various cam profiles to lift valves based on load and speed. It is also uses two rockers arms for normal working in its two intake valves and third rocker arms is placed between other two arms. If the Engine rises speed of 6000rpm, the ECU will activate and lock the center rocker arm and open the valve for long duration.

72. Cam Phasing VVT It is obtained by just shifting the cam phase angle, at the high speed, the inlet chamber rotates 30 degrees advances to enable previous intake. It is achieved by the engine management system based on the need and type of actuation.

73. Advantages of VVT It allows the recirculate internal Exhaust gas. Increased torque can be obtained. It ensures better fuel economy. It reduces nitrogen oxides. Hydrocarbon emissions can be controlled.