Automobile engineering in mechanical engineering subject Introduction, definition, classifications

What is Automobile ?

An automobile  is a self - propelled vehicle designed for road transportation of people or goods.

Definition: A motor vehicle with wheels, powered by an engine (petrol, diesel, or electricity), primarily used for road transport.

What is automobile engineering ?

Automobile engineering is a branch of engineering that deals with the design, development , manufacturing, testing and maintenance of automobiles.

Main Components are Engine, transmission, chassis, wheels & tires, body.

Type of automobile:

  • According to based on purpose:
  1. Passenger vehicles 

Designed to transport people.

Ex : - Car, Van, Jeeps, Buses.

  1. Goods vehicles

Used to carry cargo or goods.

Ex : - Trucks, Delivery vans, Tankers.

  • According to fuel type:
  1. Petrol vehicles

It runs on petrol (gasoline) 

It is common in two - wheelers and small cars.

  1. Diesel vehicles

In these vehicles diesel is used as fuel

Diesel engines are used in heavy-duty vehicles like buses, trucks.

  1. Electric vehicles (EV)

Electric vehicles are powered by batteries and run on electric motors.

These vehicles are eco-friendly, with no tailpipe emissions.

Ex :- tesla, tata nexon EV. 

  1. CNG / LPG vehicles 

These vehicles are eco-friendly such as compressed natural gas (CNG) or liquefied petroleum gas (LPG) having more environmentally friendly characteristics than petrol or diesel.

  • Based on numbers of wheels:
  1. Two-wheelers 

Ex - motorcycles , scooters

  1. Three-wheelers 

Ex :- auto-rickshaw, cargo locker.

  1. Four-wheelers

Ex :- cars , buses , trucks.

  1. Multi-axle  vehicles

These vehicles has more than four wheels and

Used for heavy transport and longitude 

  • Based on transmission (MT)
  1. Manual transmission (MT)

In manual transmission gear shifting is done by the driver.

  1. Automatic transmission (AT)

  In Automatic transmission gear shifting is done automatically.

  • Based on drive type:
  1. Front wheel drive (FWD):

In the front wheel drive system power goes to the front wheels.

  1. Rear - wheel drive (RWD)

In the rear wheel drive system power goes to the rear wheels.

  1. All - wheels drive (AWD)

In an all-wheel drive system power is delivered to all wheels.

Construction of vehicle:

Vehicle construction refers to the design and integration of various systems and components to create functioning automobiles. It includes the chassis, body, engine, transmission suspension, steering, braking and electrical system.

Main components of a vehicle:
  • Chassis (frame)

The chassis acts as the backbone of the vehicle. Support the weight of all components and hold the engine, suspension, wheels, body and more. 

  • Engine

The engine is the power source of the vehicle (IC engine or electric motor) and it converts fuel into mechanical energy to drive the wheels.

  • Transmission system

The transmission system transfers power from the engine to wheels and It Includes clutch, gearbox, propeller, shaft, differential and axle.

  • Suspension system

The suspension system connects wheels to the chassis and absorbs shocks and maintains vehicle stability.

  • Steering system:

The steering system allows the driver to control the direction of the vehicle.

  • Braking system

The braking system slows down or stops the vehicle and It includes drum brakes, disc brakes or advanced systems like ABS.

  • Bod

The outer shell of the vehicle is called Body. It Provides aesthetics , protection , andcomforttopassengers.

  • Electrical system

Electrical system Includes battery, alternator, wiring, light, sensors and ECU.


Introduction to chassis

Chassis is a French term which means “Frame” or “main structure”.

The chassis is the main supporting structure of a body vehicle. It is the base frame on which the entire body, engine transmission system, suspension system etc. are mounted. It is the skeleton of a vehicle & provides strength rigidly and support .

Main component of chassis:
  1. Frame

  2. Front axle

  3. Steering system

  4. Rear axle

  5. Suspension system

  6. Transmission system

  7. Brake system

  8. Engine

  9. Electrical system


Components are mounted in two ways

  1. Conventional construction:

In conventional construction separate frames are used and chassis & body are separate.

conventional construction Used in SUVs & some heavy duty vehicles.

  1. Frame less construction:

In frameless construction there is no separate frame employed. In unitary construction  or frame less construction chassis and body are combined which makes lighter and more efficient. Thus modern cars and Passenger vehicles used frameless construction.