Two-stroke engine

A two-stroke engine is a type of internal combustion engine that completes a power cycle with two strokes of the piston during only one crankshaft revolution. This is in contrast to a four-stroke engine that requires four strokes of the piston to complete a power cycle during two crankshaft revolutions. Fuel for a 2-stroke engine has a small amount of oil mixed into it. It is called a “2-stroke” because just one up and down movement of the piston—the 2 strokes—performs the full cycle of intake, compression, combustion and exhaust.