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Automobile Engineering Back

Automobiles : Automobile vehicles are land vehicles moving on their own power without being confined to rails.

Various Types of Automobiles

Motor Cycles : Motor Cycles includes mopads, motor cycles, scooters etc.

Passenger Cars : Passenger Cars are used for carrying two to five passengers. It also includes station wagons for carrying some load in addition to passengers.

Trucks : Panel trucks and micro buses can be used for carrying less than 3.5 tons net weight.

Tractors : Tractors includes,
  • Truck tractors
  • Wheeled tractors
  • Track tractors

Power train : The power train gives transmission power. It is made up of :
  • Clutch : A disengageable connection between engine and transmission. It is necessary to interrupt the power flow and to reset it again without causing shock loads.
  • Axle drive : In the form of bevel gears transmits the torque to the axle shaft, of the wheels joined with the axle drive is the differential thus, allowing different rotational speeds of the driving wheels when driven around a curve.
  • Transmission : It provides a grossly graduated variety of vehicle speeds and so it transfers the wheels torque.
  • Propeller shaft : It is needed with standard drives so as to make up for differences in levels and vibrations.

Vehicle Bodies : Passenger car bodies are supposed to furnish sufficient space, to be modelled appealingly and as aerodynamically as possible. The air resistance increases with the square of speed; at twice the speed the air resistance 2 x 2 = 4 times as high. Moreover, it depends on the shape of the vehicle. During last 10 years the self-supporting body structure rounded off by hoods and wind shields, succeeded in general, sports car, adhere closest to aerodynamic shapes. Special value is set, to design of the interior and exterior parts as accident preventing as possible. Common car bodies are sedans, coupe and roadster, convertible and hard top.

Petrol Engines : Two stroke engines are used in mopads, motor cycles and scooters. Cars are generally provided with four stroke engines. Mostly mopads, scooter and motor cycle engines are single cylinder, air cooled. However, cars have 4 or 6 cylinder water cooled engines. Most of the petrol engines have compression ratio of 7 to 8. The air quantities required vary with the fuel. The best utilization of fuel i.e. least consumption results in an air surplus of about 10%. This one liter of gasoline requires about 9 cu.m. of air. The maximum power output is reached at air quantity reduced by 5% to 10%.

Diesel Engines : These engines draw air during suction stroke, that is compressed to 30 to 45 at comp. ratio 14 to 22, which raises the air temperature to a range of 600 to 7000C. The fuel system consists of supply pump, the filter, the injection pump and the spray nozzles. The injection pump increases the fuel pressure to a range from 100 to 170 at. Because of the high operating pressures the parts of the power unit must be designed sturdier. Therefore, the diesel engine has a higher unit weight than the otto cycle engine.

Barking System : In barking the vehicle has to be deprived of the kinetic energy. This energy is always higher at higher speeds with conventional brakes vehicles energy is converted into irretrievable by friction. The heat has to be dispelled to the surrounding air.

Front Axle Alignment : Correct alignment of front wheels must be maintained in order to ensure of steering and satisfactory tyre life.
  • Camber : The friction of wheel inclination from a vertical position.
  • Caster : Inclination of working pin from the fore and left direction of the vehicle.
  • King pin inclination : The slant of the king pin towards the centre of the vehicle at the top and outward at the bottom.
  • Toe-in : The distance front wheels are closer together at front than at rear of axle.