B.E Mechanical (PAT.2015) Automobile Engineering University of Pune

1. Prepared By
Mr. H.D.Gurav (M.E Automotive, B.E Mechanical)
Assistant Professor
PVG COE Nashik
B E (Mechanical) (Open Elective)
AUTOMOBILE ENGINEERING

2. Syllabus
• Unit 1: Introduction and Drive Train
• Unit 2: Axles, Wheels and Tyres, Steering System
• Unit 3: Suspension and Brake System
• Unit 4: Vehicle Performance and Safety
• Unit 5: Electrical System and Vehicle
Maintenance
• Unit 6: Electric and Hybrid Electric Vehicles

3. Unit 1: Introduction to Automobile
Contents
• Introduction: Current scenario in Indian auto/ancillary
industries, vehicle specifications and classification.
• Chassis and Frames: Types of chassis layout with
reference to power plant locations and drive, various
types of frames, constructional details.
• Drive Train: Types of transmission system, necessity
and selection of clutch, necessity of gear box and
different types, fluid flywheel, torque convertor,
continuous variable transmission, , overdrive, propeller
shaft, final drive and differential.

4. 1.1 Automobile history and
development

5. 1.1 Automobile history and
development
Horse Buggy
3 w Gas Buggy
4w Gas Buggy
T Ford
Mercedes

6. 1.1 Automobile history and
development
• 100 years of history
• Horse Buggy
• Gas Buggy(1Hp)
• Karl Benz(1885 &1886)-Germany-1st Gas Buggy(3W)
• Gottlieb Daimler-Germany-(4W)
• Charles and Frank Duryea(1883)-1st Automobile in US
• Henry Ford(1886)-Model T Ford(1908)
• Detroit(1990)

7. Application
• Passenger
vehicles(Scooter)
• Goods vehicles
• (Truck, Tractor)
• Special purpose
• (Ambulance,Crane)
Load Capacity
• Light Transport
vehicle(Car,Jeep,Motor
Cycle)
• Heavy
Transport(Bus,Truck)
No of wheels and Axles
• 2W
• 3W
• 4W
• 6W
• 8 or more
1.2 Classification of Automobiles [8]
Fuel used
• Petrol
• Diesel
• Gas
• Electric
Transmission
• Conventional
• Semi-automatic
• Automatic

8. 1.2 Classification of Automobiles
Drives of the vehicles
• RH,LH(Indian,American)
• Front Wheel(Maruti 800)
• Rear W(Nano)
• All W(Thar)
Sports,Luxury &Special Purpose
• Sports(Lamborghini)
• Luxury(Mercedes Benz)
• Special (Earth scrappers, bull
dozers)
Suspension System
• Conventional(Leaf
Spring-Truck)
• Independent(Coil
Spring-motor Cycle)
Type of Body system
• Closed Car(Saloon)
• Open Car(Sports Car)
• Special Style( Estate
Car)
With Respect to make
• Heavy Vehicles
• Cars
• Motor Cycles

9. 1.3 Vehicle Layout [10]

10. Continue................
Main Components
•Wheels
•Front and rear axle
•Power unit
•Propeller Shaft
•Frame
•Transmission
•Universal Joints
•Brakes

11. Continue................
Wheels
Front & Rear axle
Propeller Shaft
Power unit
Transmission
Frames

12. Specifications of vehicles
Vehicle Specifications
Please!!!!!!
Torque
BHP
Make
Specifications
?????

13. Specifications of vehicles

14. Specifications of vehicles

15. Chassis(Ref. R.K Rajput)
• Known as carrying unit(French word) and initially
used to denotes Frames or main structure of
vehicle.
• Small vehicle : chassis = whole vehicle
• Heavy vehicles: chassis = frame
• Chassis components
• Sub divide into
– Power plant: engine and transmission
– Running Gear: Frame, suspension, steering, wheels
tyres and brakes

16. Continue.......
• Construction of chassis:
Conventional
Frameless or unitary construction

17. Classification of chassis
According to its control
• Conventional chassis (Car, Tata Truck)
• Semi forward chassis (Pickup)
• Full forward or bus chassis

18. According to fitting of engines
• Engine at front
• Engine fitted at centre (Royal tiger world
master bus)
• Engine fitted at back
Continue....

19. Continue.....
No of wheels and drive
• 4 x 2
• 4 x 4
• 6 x 2
• 6 x 4
Wheel Base
• Long wheel base

20. Frames
Introduction
• Frame or under body is main part of the chasis
on which other parts are mounted.
• Made up of Steel sections
• Long members and cross members

21. Contd.....
• Functions of frames
1. To support the chassis components
2. Withstand static and dynamic loads with un due
deflection or distortion
• Load acting on frames
1. Weight of vehicle ,occupants: vertical bending
2. Vertical load while coming across bump or
hollow : longitudinal torsion
3. Load due to side camber, side trust, wind
cornering force: lateral bending
4. Engine torque and braking: bending of side
members
5. Sudden impact load: collpse

22. Types of frame
• Steel sections
• C channel
• Box section
• Tubular section

23. Types of Frames
• conventional frame (Trucks)
• Semi integral frame (small american cars)
• Integral frame

24. Conventional Frame
• It is also known as non load carrying frame. Here
loads on the vehicles are transferred to the
suspensions by frame.
• Body work is made up of material like wood and
completely isolated from the frame deflection
with the help of rubber mountings
• This type of frame is not suited to resist torsion.

25. Semi-integral Frame
• In this type of frame load is transferred to the
body structure also.
• This Frame however is heavy.
• In semi integral frame half frame is fixed in the
front end on which engine gear box and front
suspension is mounted.
• This type of frame is used in FIAT car and
some of the European & american cars

27. Integral Frame (Frameless)
• Used now a days in most of the cars
• No frame and all the assembly units are
attached to the body
• Due to elimination of long frame it is
cheaper
• Only disadvantage is repairing is difficult.

28. •Super structure of vehicle
•Body+Chessis=Vehicle
•Made up of large no of Steel pressing parts
•Body is connected to Chassis at numerous points, rubber or
felt strips
•Basic Requirements of body:
•Light weight, cheap & ease in fabrication,Less
components, aerodynamic property, good access to
engine and suspension, adequate space to
passenger,aesthetic
•Eg.
•Closed Car-provision of Luggage space
•Closed Bus
•Open truck-rear panel for loading and unloading
•Use of welded attachments to body
Vehicle Body [10]

29. Type Of Vehicle Bodies
Type of
vehicle body

30. Type Of Vehicle Bodies

31. Type Of Vehicle Bodies

32. Material for Frame
• For pressed frame:
– Mild steel
– Carbon sheet steel
– Nickel alloy steel

34. Drive Train and Transmission

35. Topics to be covered
• Classification of clutches, Single-plate, Multi-plate, Cone
• Diaphragm spring, Centrifugal, Clutch materials, Electromagnetic,
• Vacuum operated, fluid flywheel
• Necessity of gear box, Manual gear box -Constant mesh, Sliding
mesh
• Synchromesh, Geared automatic transmission, Torque convertor
• Epicyclic, Continuous variable transmission, Electronic transmission
control,
• overdrive, Propeller Shaft, Constant Velocity joint,
• Differential and final drive, Non slip differential ,hotchkiss drive,
torque tube drive

36. Transmission System
• Function of transmission:
- It is used to transmit engine torque to the driving
wheels to drive the vehicle on the road.
4

37. Clutch
• Definition: It is a mechanism that transmit rotary
motion of one shaft to the other whose axis is
coincident with that of the first.
• Requirement of Clutch:
– Torque transmission
– Gradual Engagement
– Heat Dissipation
– Dynamic balancing
– Vibration Damping
– Size
– Inertia
– Pedal Play

38. Clutch Terms
• Engaged
• Disengaged
• Clutch disengaged (Clutch pedal pressed)
• The clutch is disengaged when
– Starting the engine
– Shifting the gear
– Stopping the vehicle and
– Idling the engine
• Clutch engaged
• Clutch pedal is released

40. Dry Friction Clutches
1. Cone Clutch
2. Single Plate
3. Multiplate clutch
4. Semi centrifugal clutch
5. Centrifugal Clutch

41. Working Principle of Friction Clutch

42. 1. Cone Clutch
• Advantage
Large normal Force
acting on the surfaces
than the axial force
• Disadvantages
Difficult to disengage
innner cone (< 200)
Unavoidable axial
movement of inner
cone

43. 2. Single plate clutch

45. 3. Multiplate clutch

46. Working of multiplate clutch

47. Diaphragm Spring Type Single Plate
Clutch

48. Fulcrum Spring
Pressure plate
Diaphragm assembly

51. Working of diaphragm type single
plate clutch

52. Centrifugal Clutch

53. Clutch Plate (Friction Disc)
Cushioning Spring
Clutch Facing
Torsional Spring

54. Clutch materials
• Types of friction material
1. Millboard type
– Only asbestos sheets is used
2. Moulded type
– Mixing of asbestos fibres with suitable binders,
heating and pressure moulding in dies
3. Woven Type
– Cloth impregnated with certain binders

55. Common Clutch facing materials
• Leather: dry leather with iron COF 0.27
• Cork: on dry steel on iron –COF 0.32
• Fabric: COF 0.4 (can not used at high temp.)
• Asbestos: COF 0.2 but good anti heat properties
• Reybestos and feredo: COF 0.35
• Non asbestos clutch facing: Glass fibres
– SW3-AF (COF 0.28 to 0.36)
– HWK 200 (COF 0.39 to 0.40)
– Graphite material
– Sintered metal

56. Electromagnetic Clutch

57. Working of electromagnetic clutch

58. Vacuum Operated clutch

59. Fluid Flywheel

60. Fluid Flywheel

61. Fluid Flywheel

62. Working

63. Function Of A Gear Box
• Torque ratio between the engine and
wheels to be varied for rapid acceleration
and for climbing gradients.
• It provides means of reversal of vehicle
motion.
• Transmission can be disconnected from
engine by neutral position of gear box

64. Gear Box
Necessity Of Gear Box In An Automobile
• Variation of resistance to vehicle motion at
various speed.
• Variation of tractive effort at various speed

65. 1. Total resistance to vehicle motion
i. Resistance due to wind :proportional to the
square of the vehicle speed
ii. Resistance due to gradient: Remains
constant at all speed. This is component of
weight parallel to road
iii. Miscelleneous: Type of the road, tyre friction
etc.

66. Tractive effort
Total resistance to vehicle motion at different gradient

67. Transmission Necessity

68. Types of Transmission
• Some selective type of mechanical gear
boxes are
1. Sliding mesh gear box
2. Constant mesh gear box with positive dog
clutch
3. Constant mesh gear box with synchromesh
device.

71. Synchromesh Gear Box

73. Engagement of Direct Gear

74. Epicyclic Gear Train

76. Torque Convertor

77. Pulley based CVT
Speed Increases
Speed Decreases

78. Belt Design

79. Variator Assembly

80. Freewheel

81. Overdrive

82. Overdrive

84. Propeller shaft

85. Propeller Shaft
• Shaft
– Withstand torsional load
– Well balanced to avoid whirling at high speed
– Steel, Al or composite material
• Universal Joint
– Accounts up and down motion of the rear axle
– Cardon joints- high speed constant velocity joint with
the option of intermediate bearing ,limited slip
devices and crash feature
• Slip Joint
– Adjust the length of the propeller shaft

86. • Whirling effect
1. Increase in dia
2. Critical speed is inversely proportional to
square of length of shaft
3. Divided shafts with internal bearings
Propeller Shaft

87. Universal Joint

88. Flexible ring universal coupling
Spider
Limitation: Variation in the speed of the driven shaft at various inclination
Remedies: Use of two universal Joint

89. Constant velocity joint
• Generally used for front wheel drive
• Two types
• Fixed type (outboard): at wheel end
• Plunging types (inboard): at differential end

91. Axle shaft
Transmits power from inner to outer CV-joint

92. Rzeppa Joint - Exploded View

93. Rzeppa CV

94. Rzeppa Joint - Exploded View

95. Tripod Joint

96. Final Drive
•Final drive is the last stage of power transfer from propeller
shaft to rear (or front if – automobile is front wheel driven)
axles and then to wheels. It turns the propeller shaft motion at
right angle to drive the rear axle.
•Consists of Bevel pinion and crown wheel or worm and worm
wheel arrangement
•Bevel gear=propeller shaft
•Crown wheel drive goes to the differential
•Three Types of the gears are used
•Straight Bevel Gears
(uneven transfer of motion)
•Spiral bevel gears
•Hypoid bevel gears

97. Differential
Pinion Drive Gear: transfers power from
the driveshaft to the ring gear.
Ring Gear: transfers power to the
Differential case assembly.
Differential case assembly: holds the
Ring gear and other components that drive the rear axle.
Rear drive axles: steel shafts that transfer torque from the differential assembly to the
drive wheels.
Rear axle bearings: ball or roller bearings that fit between the axles and the inside of the
axle housing.
Axle housing: metal body that encloses and supports parts of the rear axle assembly.
Side/spider gears: help both wheels
to turn independently when turning.

98. Power flow
http://auto.howstuffworks.com/differential2.htm
•Drive shaft spins the Pinion gear.
•Pinion gear turns the larger ring gear to produce
gear reduction.
•Ring gear attached to differential case, hence it
rotates with the ring gear.
•Differential case spins the sun gears which are attached to the axles.
•Axles transfer the power to the wheels.

99. Function
•Transfers power from driveshaft to the wheels.
•Provides final gear reduction.
•Splits amount of torque going to each wheel.
•Allow the wheels to rotate at different speeds in turns.

100. Differential Gear box working
principle(Ref G B NARANG )

101. Hotchkiss Drive
• The Hotchkiss drive is a system of power
transmission
• Rear axle drive
• It was the dominant form of power
transmission for front-engine, rear-wheel
drive layout cars in the 20th century
• Requirement of mechanism to transfer driving
and braking efforts to chassis

103. Construction of Hotchkiss Drive
• Simplest and most widely used type of rear axle
drive .
• The spring besides taking weight of the body also
take the torque reaction , driving thrust and side
thrust .
• propellar shaft is provied with two universal
joints also a sliding joint .
• The front end of the spring is fixed rigidly on the
frame while the rear end and is supported in the
shackle .

106. Torque Tube

107. Torque Tube

108. References
1. K. Newton and W. Seeds, T.K. Garrett, “Motor Vehicle” 13th Edition,
Elsevier publications
2. Hans Hermann Braess, Ulrich Seiffen, handbook of Automotive
Engineering, SAE Publications
3. William H. Crouse.,”Automotive Mechanics„ - Tata McGraw Hill
Publishing House
4. Joseph Heitner,”Automotive Mechanics„ -C.B.S Publishers And
Distributors
5. SAE Manuals and Standard
6. Automobile Mechanics -.N. K. Giri
7. Automobile Electrical Equipment -P. S. Kohali
8. Narang G. B. S , “Automobile Engineering” - S. Chand and Company Ltd.
9. Singh Kripal - Automobile Engineering -Volume 2 New Chand Jain.
10. R.K.Rajput-Automobile Engineering