Unit 3 basic parts of the automobile

Basically, the automobile consists of four components. The­se are:

1. The engine.

2. The frame work, or support for the engine and wheels.

3. The power train_, or mechanism that transmits the power from the engine to the wheels.

4. The body.

To these may be added a fifth component, the car-body acce­ssories: the heater, lights, radio, and other devices that cont­ribute to the convenience and comfort of the driver.

The engine of the automobile is usually referred to as an internal-combustion engine because gasoline is burned within its cylinders or combustion chambers. This burning, or combustion, takes place at such high speed as to be termed as “explosion”. The high pressure thus created causes a shaft to turn or rota­te. This rotary motion is transmitted to the car wheels by the power train so that the wheels rotate and the car moves.

Most automobile engines have six or eight cylinders, althou­gh, some four-, twelve-, and sixteen-cylinder engines are in use.

Automobile engines must be small and light. Nearly all auto­mobile engines are water-cooled, but some are cooled by air blast produced by special fans.

Unit 4 where diesel engines are used

Diesel engines are especially suitable where an independent source of power is required. That is why diesel engines are widely used in ships, locomotives, mobile equipment of all sorts and isolated power plants.

Nowadays railroad locomotives are mostly diesel-electric: the diesel engine drives an electric generator which supplies electric power to electric motors connected to the wheels. Compared to steam locomotives, diesels use much less fuel and their service life is much longer. Compared to straight electric locomotives, diesels do not require overhead wires or third rails.

Diesel engines are used for trucks, buses, tractors, construction machinery, logging equipment. The principle reason is the saving in cost of fuel the diesel engine uses fewer gallons of less costly fuel than the gasoline engine. Another advantage of the diesel is its greater pulling power when it slows down under a heavy load. In other words, the diesel loses less power at reduced speed than the gasoline engine.

Diesel engines are used in a great many kinds of stationary power .plants: in isolated service stations, railway water stations, lumber camps, power plants, oil-well drilling_, vacation resorts. The chief reason is saving in cost of fuel compared to the cost of fuel of small steam or gasoline power plants. The following advantages of diesel are also important: independence of water supply, lightness and compactness, freedom from fire danger, and ability to start quickly.

Diesels are widely used in marine service of many kinds such as sea-going vessels /both passenger and freight/, motor-boats, ice-breakers. The main reason for these uses of diesels is, again, lower cost of fuel compared to stream.

Diesel locomotives are now preferred to electric locomotives for mine-haulage and for tunnel construction .because they are less expensive in operating cost. The exhaust gases of diesel locomotives contain less poisonous substances, which is an important bjection to gasoline engines. So the applications in which diesel engines are widely used are numerous. The reason why they are preferred to gasoline engines is that advantages, as a whole, are more important than their drawbacks.