Automobile is a self-propelling device. It has a source of power (IC engine) and a power train to transmit the power from the engine to the wheels in order to move. An IC engine propels cars, buses, trucks, scooters, locomotives, ships, planes, etc.
1. Load carriers or single unit vehicles: These are commercial four-wheel type – two-axle design. Front axle for steering and rear axle for driving the vehicle. Passenger cars, buses, trucks and lorries are the examples of this category. 2. Articulated vehicles or double unit vehicles: It contains a powered unit and trailer. Usually the cabin is attached to the powered unit through hinges. Double duckers, earth moving equipment, dumpers, etc. are the examples of this category. 3. Heavy tractor vehicles: These are used for moving heavy loads at low speeds. Agricultural tractors and earth moving equipment are the examples of this category.
i) Based on use:
a) Scooter, motor cycle, moped;
c) Cars, mini bus; d) Bus, lorry, truck e) Tractor, earth-moving equipment like scrapper, dumper, etc. ii) Based on capacity:
a) Light transport vehicle – car, jeep; b) Medium transport vehicle – Tempo, minibus c) Heavy transport vehicle – Bus, lorry, truck
iii) Based on fuel:
a) Steam; b) Petrol; c) Diesel; d) Gas – gas turbine driven truck iv) Based on drive mechanism:
a) Left hand drive mechanism - American
b) Right hand driven mechanism – Indian
c) Front wheel drive mechanism – Volks Wagon
d) Rear wheel drive mechanism - All Indian vehicles
e) All four wheel drive mechanism – Jeep.
v) Based on number of wheels:
a) Two wheelers: Scooters, motor cycle, moped
b) Three wheelers: Auto, Tempo
c) Four wheelers: Car, jeep, minibus
d) Six wheelers: Bus, lorry, truck
vi) Based on transmission system:
a) Conventional; b) Semi-automatic; c) Automatic
vii) Based on suspension system:
a) Conventional: uses leaf springs
b) Independent: uses coil springs & torsion springs.
Layout of an Automobile:
Fig. Layout of an automobile
Layout of an automobile consists of a frame on which the engine and the bodywork are fitted. The engine with its cooling, lubrication, ignition or fuel injection and fuel supply system is fitted at the front end of the frame. A radiator is provided in front of the engine to cool the circulating water. A clutch to engage and disengage the drive when changing gears or stopping the vehicle, a gear box to change the torque on the road wheels depending on load requirements through different gear ratios, a propeller shaft to transmit the power from the gear box to the final drive along with an universal joint at either end to take care of the difference in elevation of the gear box and differential and as well as to take care changes in shaft alignment due to road surface condition, a differential to turn the rear wheels at different speeds when the automobile is taking turns, two half shafts to rotate the wheels, are provided with the engine to constitute a power transmission or train. An electrical system (1) to develop electrical energy through the engine operated dynamo (generator), (2) to start the engine through an electrical motor and battery, (3) to provide the power for horn, wind screen wiper, head lights, trafficators (indicator lights) etc. is provided on the layout. Both the front and rear axles are fixed to frame through spring suspension system to provide cushioning from road shocks. Wheels support the load of the vehicle and passengers and run the vehicle. Hollow rubber tyre along with rubber tubes filled with air under pressure support the load. To control the movement of vehicle, a breaking system is provided. A brake drum with friction material lined brake shoes in each wheel provides the necessary braking action whenever the shoes are squeezed on the drum. The front axle is so designed to provide steering through various linkages. A...
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