Classification of Automobiles

An automobile is a vehicle that is capable of propelling itself. Since 17th century, several attempts have been made to design and construct a practically operative automobile.

Today, automobiles play crucial role in the social, economic and industrial growth of any country.

After the designing of Internal Combustion Engines, the Automobile industries has seen a tremendous growth.

Classification of Automobiles :

Automobiles can be classified into several types based on many criteria. A brief classification of automobiles is listed below:

1. Based on Purpose :

• Passenger vehicles : These vehicles carry passengers. e.g: Buses, Cars, passenger trains.
• Goods vehicles : These vehicles carry goods from one place to another place. e.g: Goods lorry, Goods carrier.
• Special Purpose : These vehicles include Ambulance, Fire engines, Army Vehicles.

2. Based on Load Capacity:

• Light duty vehicle : Small motor vehicles. eg: Car, jeep, Scooter, motor cycle
• Heavy duty vehicle :  large and bulky motor vehicles. e.g: Bus, Truck, Tractor

3. Based on fuel used:

• Petrol engine vehicles : Automobiles powered by petrol engine. e.g: scooters, cars, motorcycles.
• Diesel engine vehicles : Automobiles powered by diesel engine. e.g: Trucks, Buses, Tractors.
• Gas vehicles : Vehicles that use gas turbine as power source. e.g: Turbine powered cars.
• Electric vehicles : Automobiles that use electricity as a power source. e.g: Electric cars, electric buses.
• Steam Engine vehicles : Automobiles powered by steam engine. e.g: Steamboat, steam locomotive, steam wagon.

4. Based on Drive of the vehicles :

• Left Hand drive : Steering wheel fitted on left hand side
• Right Hand drive : Steering wheel fitted on right hand side
• Fluid drive : Vehicles employing torque converter, fluid fly wheel or hydramatic transmission.

5. Based on number of wheels and axles :

• Two wheeler : motor cycles, scooters
• Three wheeler : Tempo, auto-rickshaws
• Four wheeler : car, Jeep, Bus, truck
• Six wheeler : Buses and trucks have six tires out of which four are carried on the rear wheels for additional reaction.
• Six axle wheeler : Dodge(10 tire) vehicle

6. Based on type of transmission:

• Automatic transmission vehicles: Automobiles that are capable of changing gear ratios automatically as they move. e.g: Automatic Transmission Cars.
• Manual transmission vehicles: Automobiles whose gear ratios have to be changed manually.
• Semi-automatic transmission vehicles: Vehicles that facilitate manual gear changing with clutch pedal.

7. Based on Suspension system used:

• Convectional - Leaf Spring
• Independent - Coil spring, Torsion bar, Pneumatic.

Modes of Heat Transfer - Conduction, Convection and Radiation

Heat is a form of energy which transfers between bodies which are kept under thermal interactions. When a temperature difference occurs between two bodies or a body with its surroundings, heat transfer occurs.

Heat transfer occurs in three modes:
1) Conduction 2) Convection and 3) Radiation

Conduction :

In Conduction, heat transfer takes place due to temperature difference in a body or between bodies in thermal contact, without mixing of mass. The rate of heat transfer through conduction is governed by the Fourier's law of heat conduction.

Q = -kA(dT/dx)

Where: Q is the heat flow rate by conduction

K is the thermal conductivity of body material
A is the cross-sectional area normal to direction of heat flow and
dT/dx is the temperature gradient of the section.

Convection :

In convection, heat is transferred to a moving fluid at the surface over which it flows by combined molecular diffusion and bulk flow. Convection involves conduction and fluid flow. The rate of convective heat transfer is governed by the Newton's law of cooling.

Q = hA(Ts-T∞)

Where: Ts is the surface temperature

T∞ is the outside temperature
h is the coefficient of convection

Radiation:

In radiation, heat is transferred in the form of radiant energy or wave motion from one body to another body. No medium for radiation to occur. The rate of heat radiation that can be emitted by a surface at a thermodynamic temperature is based on Stefan-Boltzmann law.

Q = σT⁴

Where: T is the absolute temperature of surface

σ is the Stefan-Boltzmann constant.