How many rotations does the four-stroke cycle occur over?

In a four-stroke cycle engine, one complete cycle of intake, compression, power, and exhaust strokes requires two rotations of the crankshaft. During the first rotation, the intake and compression strokes take place. The intake stroke pulls in air and fuel mixture, followed by the compression stroke where the piston compresses this mixture in the cylinder.

In the second rotation, the power stroke occurs when the ignited mixture forces the piston down, followed by the exhaust stroke which pushes the spent gases out of the cylinder. This sequence is fundamental to the operation of a four-stroke internal combustion engine, clearly demonstrating that two rotations are necessary to complete a full cycle.