ENGINES AND MOTORS PROFESSIONAL ENGLISH IN USE FOR ENGINEERING

 

PROFESSIONAL ENGLISH IN USE FOR ENGINEERING UNIT 40. ENGINES AND MOTORS

 

A Types and functions of engines and motors The term engine usually refers to petrol engines, diesel engines and jet engines (or jets). In engineering, motor usually means electric motor – but in general language ‘motor’ can also refer to petrol and diesel engines. Engines and motors power (or drive) machines by generating rotary motion – for example, to drive wheels. In jet engines, compressors and turbines rotate to generate thrusts – pushing force, produced by forcing air from the back of the engine at high velocity. B Internal combustion engines Petrol and diesel engines are internal combustion engines. This means they are driven by the combustion (burning) of fuel in enclosed, sealed spaces called combustion chambers. In petrol and diesel engines, the combustion chambers are cylinders surrounded by a cylinder block and closed at the top by a cylinder head. Each cylinder contains a piston. The number of piston cylinders in an engine varies – engines in small motorcycles have only one, while sports car engines may have twelve. EXERCISES 40.1 Complete the text about diesel engines using words from A and B opposite. Diesel engines differ from (1)_________ engines in one key respect: they are not fitted with a (2)_________, in each cylinder, to ignite the fuel. This is because when a (3)_________ of diesel and air is compressed inside a hot (4)_________, it will 40.2 Look at the cross-section of an engine, and label it using words and expressions from B opposite.

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