There are two main types of petrol engines, reciprocating engines and rotary engines. Reciprocating engines have pistons that move up and down or back and forth. A part called a crankshaft changes this reciprocating motion into rotary motion. A rotary engine, also known as a Wankel engine, uses devices called rotors instead of pistons. The rotors produce rotary motion directly. This article discusses reciprocating engines, the more common type.
Reciprocating petrol engines are classified in a number of ways. These include :
(1) number of piston strokes per cycle, (2) type of compression, (3) by the way they are cooled, (4) valve arrangement, (5) cylinder arrangement, and (6) way they are supplied with air and fuel.
