| Automobile
Engineering |
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Automobiles : Automobile vehicles are land vehicles
moving on their own power without being confined to rails.
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Various Types of Automobiles |
Motor Cycles : Motor Cycles includes mopads, motor
cycles, scooters etc.
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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.
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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
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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.
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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%.
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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.
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