Car needs the engine as energy source. The engine provides mechanical power to keep the car moving. Piston engines classifications by the next signs.

1. The purpose: transport and stationary;
2.  The Operating cycle: four-stroke and two-stroke engines;
3.  Method of fuel injection: external carburation, internal carburation, injection by spaying.
4.  The combustion type of fuel mixture: ignition forced (from spark plug) and ignition due to compression.
5.  Type of fuel: gasoline engine, gas-power engine, diesel engine.
6.  Number of cylinders: one-cylinder engine, multi cylinder engine (double-, three-, four-, six-, eight- cylinder engines).
7.  By cylinders arrangement: cylinder-in-line, v-arrangement, flat.
8.  Type of cooling: engines withliquid cooling and air cooling.