The diesel and petrol engines that are used in most cars are highly
similar. In essence, they are internal combustion engines that work
using a two or four-stroke cycle. In an internal combustion engine, the
power cycle is made up of four phases: intake, compression, power and

In the intake phase, air is drawn into cylinder through the opening
intake valve. In the compression phase, the intake valve closes and air
is compressed with fuel. At this point, the mixture of fuel and air is
ignited to cause an explosion. It is this explosion that causes the
piston to downwards and drive the crankshaft to produce motion. This is
the power phase. The final phase is exhaust where the spent air-fuel
mixture is expelled out of the cylinder through the opening exhaust
valve so that a new cycle may begin.