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Direct injection

Direct injection Inlet port Injector Piston Combustion chamber (piston cavity)

Direct injection means the fuel is squirted directly into the combustion chamber in the top of the piston crown.

The chamber shape is better, but it is more difficult to make the fuel mix properly with the air and burn without producing the harsh, characteristic diesel 'knock'.

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