- Introduction A four stroke or four cycle engine is an engine operating on the principle of internal combustion, in which pistons (one per cylinder in multi-cylinder engines) completes four separate strokes for each thermodynamic cycle, which is accomplished over two consecutive revolutions of the engine’s crankshaft.
These four strokes are: the Intake stroke, the Compression stroke, the Power stroke and the Exhaust stroke. The sectional diagrams below illustrate these four strokes in a single-cylinder engine; the curved red arrows represent the direction of rotation of the camshafts (small arrows) and the engine’s crankshaft (larger arrows). The ...
