Diesel fuel is less-refined oil product that petrol and is used in an engine that uses higher compression than a petrol engine to ignite the fuel, instead of a spark plug.

Diesel cars tend to use much less fuel than petrol cars.

This is especially the case with large 4x4 wagons and off-roaders that can use half as much fuel as their petrol equivalents.

Diesel engines producing good performance tend to be turbocharged.