Skip to main content

The compression-igntion engine

The compression-igntion engine Combustion chamber Designed to promote turbulence so that the fuel and air are well mixed. Bottom end The main parts of the engine need to be stronger than petrol equivalents. Connecting rod Piston Ignition No spark plugs are needed because the mixture is ignited by compression heat. Glow plugs These preheat the combustion chamber for cold starts. Bearing cap Bracing web

Many car diesels are based on existing petrol engine designs, but with the major components strengthened to cope with the higher pressures involved.

Fuel is supplied by an injection pump and metering unit, which are usually mounted on the side of the engine block. No electric ignition system is needed.

Explained in

    How a diesel engine works

    Traditionally, diesel engines have always been seen as noisy, smelly and underpowered engines of little use other than in trucks, taxis and vans. But as diesel engines and their injection system controls have become more refined, the 1980s have seen that situation change. In the UK in 1985 there were almost 65,000 diesel cars sold (about 3.5 per cent of the total number of cars sold), compared with only 5380 in 1980. Read more