There are a number of different types of car engines in today's road and race cars, and the number is growing especially with emerging technologies like Hybrids.
Most cars these days use what is called a four-stroke combustion cycle to convert gasoline into kinetic motion. This four-stroke approach is known as the the Otto cycle, in honor of Nikolaus Otto who invented it in 1867.
Intake stroke- air and fuel are taken into the cylinder as the piston moves downwards.
Compression stroke- where the air and fuel are compressed by the upstroke of the cylinder.
Combustion stroke- compressed mixture is ignited and the expansion forces the cylinder downwards.
Exhaust stroke- waste gases are forced out of the cylinder.
First of all lets get a understanding of the different types of engine layouts commonly found in cars today. As Engines can come in an array of different designs, including Straight/Inline, V Type, Boxer, Rotary Wankel and even Diesel: