How many strokes make up a complete four-stroke cycle? The answer is 4. A conventional four-stroke piston engine completes its cycle through intake, compression, power and exhaust. Each stroke moves the piston once from one end of the cylinder to the other, alternating between top dead center and bottom dead center.
The intake stroke draws in air, or an air-fuel mixture depending on the engine design. Compression then raises the mixture’s pressure. During the power stroke, combustion forces the piston downward and supplies useful work. Finally, the exhaust stroke pushes burned gases out of the cylinder. The sequence then repeats.
A complete four-stroke cycle takes two crankshaft revolutions, or 720 degrees of crankshaft rotation. The camshaft typically turns at half crankshaft speed so that the intake and exhaust valves open at the correct times. The power stroke is the only one that directly produces positive work, while the crankshaft carries the piston through the other three strokes.