This document provides an introduction and overview of automobiles. It defines an automobile and describes its main components like the frame, engine, transmission system, and wheels. It then summarizes the early history of automobile development from 1769 to the 1900s. Next, it discusses the brief history of automobiles in India from the 1930s to present day. The document concludes by describing the classification, parts, performance and power characteristics of automobiles.

1. Introduction to
Automobile
By: Ratnadeepsinh Jadeja

2. Introduction
• An “automobile” is a self propelled
vehicle driven by an internal
combustion engine and is used for
transportation of passengers and
goods on ground.
• The modern automobile, in general,
is essentially a transportation
equipment unit.

3. Introduction
• It consist of a “frame” supporting the “body” and certain “power developing
and transmitting units” which are further supported by “tyres and wheels”
through “springs and axles”.
• An “engine” supplies the power, which is delivered by the “transmission
system” to the wheels through the clutch or fluid coupling.
• Mobile or motive means one which can move. Automobile or Automotive
means one which itself can move.
• The different names for the automobile are:
Auto, Automobile, Autocar, Autobuggy, Car, Motor, Motorcar, Motor vehicle,
Motor coach, Motor wagon, Horseless coach

4. Brief History of
Automobile
1769 – French engineer
Captain Nicholas Cugnot of
France built the first road
vehicle propelled by its own
power (Attained a speed of
about 2.5 mph in 15 min.)

5. Brief History of
Automobile
1801 – First steam
carriage built by Richard
Trevithick in England.

6. Brief History of
Automobile
1804 – Oliver Evans built the
finest American self-propelled
steam vehicle.

7. Brief History of
Automobile
1827 – Onesiphare
Pacqueur of Drance
invented first differential.

8. Brief History of
Automobile
1832 – First 3 speed
Transmission patented by
W. H. James in England.

9. Brief History of
Automobile
1880 – German and French
efforts developed an internal
combustion engine vehicle
(which was used to carry
fruits). The present day
automobile is the
development of this vehicle.

10. Brief History of
Automobile
1885 – Benz in Germany
developed tricycle propelled
by an internal combustion
engine.

11. Brief History of
Automobile
1886 – One of the first
gasoline engine powered
automobiles by Gottlieb
Daimler of Germany.

12. Brief History of
Automobile
1894 – Panhard and Levassor
in France developed a car
which incorporated the chief
features of the modern
automobile.

13. Brief History of
Automobile
1895 – First motor car race
held.

14. Brief History of
Automobile
1897 – First car arrived in
India.

15. Brief History of
Automobile
1900 – The design of the
automobile was so improved
that it awakened the public to
the fact that this new form of
transformation was really
practical for use.

16. Brief History of
Automobile
1902 – First volume of
production car “The Curved
Dash Oldsmobile” in America.

17. Brief History of
Automobile
1906 – The production
and sale of these vehicles
became a business.

18. Brief History of
Automobile
1908 – Ford “T” model car
produced in America by Ford
Motor Company.

19. Brief History of
Automobile
1911 – First electric self
starter installed in the
automobile.

20. Brief History of
Automobile
1920 – There was a gradual
change and refinement in
automobile design ….

21. Brief History of
Automobile in India
1930s – India was an importer
of automobiles

22. Brief History of
Automobile in India
1940s – The Indian
automobile industry started
its own manufacturing unit.
1960 - 1980 – The market was
largely dominated by
Hindustan Motors, with the
Ambassador model

23. Brief History of
Automobile in India
1983 – Maruti came into the
competition and swept the
market

24. Brief History of
Automobile in India
1984-92 – The Govt. of India
started promoting the
automobile industry; Delhi
Auto Expo was established

25. Brief History of
Automobile in India
2011 – India became the 6th
largest car manufacturer in
the world. India is Asia’s 2nd
largest two-wheeler
manufacturer.

26. Classification of Automobiles
• Automobiles can be classified with different regards which are as under:
1. Purpose – Passenger & Goods Carrier
2. Fuel used – Petrol, Diesel, Gas, Electric & Steam
3. Capacity – HTV or HMV, LTV, LMV & Medium
4. Construction – Single unit & Articulated & Tractor
5. Drive – LH, RH & Fluid drive
6. Wheel and axle – Two, Four & Six wheeler, 4 × 2, 4 × 4, 6 × 2, 6 × 4
7. Suspension system – Conventional & Independent
8. Body and number of doors – Sedan, Convertible, Station wagon, Pick ups,
Special purpose vehicle
9. Transmission – Conventional, Semi automatic, Automatic

27. Parts of an Automobile

28. Parts of an Automobile
Every automobile consists of the following two main parts:
1. Machine Portion
2. Carriage Portion i.e., Body.
1. Machine Portion – consists of the following three basic units:
1.1 – The “chassis and transmission”
1.2 – The “engine”
1.3 – The “electrical equipment”.

29. Chassis
This part of the automobile supports
its body, engine and transmission
system.
The automotive chassis includes the
following:
• The frame
• Spring and shock absorbers
• Steering system
• Brakes
• Tyres and wheels.

30. Transmission
This unit transmits power from
the engine to the wheels.
It consists of the following:
• Clutch
• Gear Box
• Universal Joint
• Final drive
• Axles and differential

31. The Engine
An engine in an automobile is the
source of power. A petrol engine
consists of the following four basic
system.
• Fuel system
• Ignition system
• Lubricating system
• Colling system

32. Electrical system
The automotive electrical system
consists of the following
• The battery
• Dynamo
• Alternators
• The ignition starting and lighting
systems.

33. Body or Carriage
• It is the portion of an automobile where
passengers have their seats or where the
cargo to be carried is placed.
• The body is designed according to the nature
of cargo to be carried.

34. Description of an
Automobile
The following factors should be taken into
consideration while writing down the
description of an automobile.
1. Type
2. Capacity
3. Make
4. Drive
5. Model

35. Performance of an Automobile
The torque produced by the engine is transmitted through the drive line to the road wheels to propel the
vehicle ( the crank shaft is coupled to the driving road wheels through clutch, gear box, propeller shaft,
differential and axle shafts).
The torque is measured in Nm (SI units); the actual power delivered by the engine is known as Brake
Power (B.P.) and is measured by dynamometer or prony brake.
𝐵. 𝑃. =
2𝜋𝑁𝑇
60 × 1000
𝑘𝑊
Where, T = Torque, Nm and
N = Speed in rpm

36. Performance of an Automobile
The torque available at the contact between driving wheels and road is referred to as tractive effort.
Let, Tw = Torque at driving wheels,
G = Gear box ratio,
ηt = Overall transmission efficiency,
Te = Engine torque (Nm), and
N = rpm of the crankshaft.
Then,
𝑇𝑤 = 𝐺 × ηt × 𝑇𝑒
Engine Torque Te,
𝑇𝑒 =
𝐵. 𝑃.× 60 × 1000
2 𝜋 𝑁
Tractive effort,
𝐹 =
𝑇𝑤
𝑅𝑤
Where Rw = Radius of the driving wheel

37. Performance of an Automobile
𝑅. 𝑃. 𝑀. 𝑜𝑓 𝑑𝑟𝑖𝑣𝑖𝑛𝑔 𝑤ℎ𝑒𝑒𝑙 =
𝑉
2𝜋𝑅 𝑤
Where , V = Vehicle speed in m/min, and
Rw = Radius of wheel in metres.
Vehicle speed = Wheel circumference × N/G
𝑉 =
2𝜋𝑅 𝑤 𝑁
𝐺
𝑚/𝑚𝑖𝑛
• The ratio between engine rpm and vehicle speed depends upon overall gear ratio.
• The speed of propeller shaft is always less than the engine speed except in top gear.
• The speeds of axle shafts are always less than the speed of propeller shaft owing to final drive gear
reduction.

38. Power at Driving Wheels:
• The power available at the driving wheels to drive the vehicle ranges from about 60 to 70 %. The
various power losses which take place between engine and driving wheels are:
1. Power loss due to friction of piston, bearings and gear in the engine (the power available at engine
flywheel is about 85%).
2. Power loss from clutch to drive wheels due to friction in clutch, gearbox, universal joints, final drive,
differential and between tyres and ground.
3. Transmission line losses.
• The thrust known as tractive effort provided by the engine at driving road wheels varies at different
engine speed and gear positions.

39. Power at Driving Wheels:
• A moving vehicle is opposed by various forces known as resistances. For keeping the vehicle moving, a
driving force or tractive effort (F) equal to the sum of all the resistances has to be applied to it.
• The main forces which oppose the motion of a vehicle are:
1. Rolling Resistance.
2. Wind or air resistance.
3. Gradient resistance.

40. Rolling Resistance
• It is mainly due to the friction between wheel tyres and road surface. It depends upon the following
factors:
1. Load on each road wheel;
2. Type of tyre tread;
3. Wheel inflation pressure;
4. Nature of road surface.
• It is measured in kg or N and is expressed as kg/tonne or N/tonne of vehicle weight or as a percentage
of the vehicle weight. Rolling resistance on average type of road surface is between 1 to 2 % of vehicle
weight.
Rolling resistance, 𝑅 𝑟 = 𝑘 𝑟 × 𝑊
Where, kr = Constant of rolling resistance, and
W = Total weight of vehicle.

41. Wind or air resistance
• This type of resistance depends upon the following factors:
1. The shape and size of the body;
2. Air velocity;
3. Speed of the vehicle.
• It increases as the square of the vehicle speed owing to which much importance is given to
streamlining and frontal area of modern automobiles. In calculating air resistance, air velocity is usually
neglected.
• Air resistance, 𝑅 𝑎 = 𝑘 𝑎 𝐴 𝑉2
Where, Ka = Coefficient of air resistance,
A = Projected frontal area, and
V = Vehicle speed
• The values of Ka for 1. Best streamline cars – 0.00235
2. Average cars – 0.0032
3. Buses and Trucks – 0.0046

42. Gradient resistance
• This resistance is due to the steepness of road gradient. It is subjected to vehicle weight and road
gradient. It does not depend upon vehicle speed.
• Gradient resistance, Rg = W/G, or W sin θ
Where W = Total weight of vehicle,
G = Gradient, and
θ = Inclination. (For small values, tan θ = sin θ)
When the vehicle is moving along a level road, total resistance,
𝑅𝑡𝑜𝑡𝑎𝑙 = 𝑅 𝑟 + 𝑅 𝑎 , and
While moving up a gradient,
𝑅𝑡𝑜𝑡𝑎𝑙 = 𝑅 𝑟 + 𝑅 𝑎 + 𝑅 𝑔

43. Power to weight Ratio
• An automobile’s performance much depends upon its power to weight ratio.
• A well designed streamline car having a higher power to weight ratio registers a low fuel consumption
at any given speed.
• Power to weight ratio (BHP per ton) in small and medium cars range from 30 to 90; and special high
performance cars have the ratios up to 230.