A four-stroke engine is a type of internal combustion engine that completes a power cycle in four distinct strokes of the piston. These strokes are known as intake, compression, power, and exhaust. During the intake stroke, the engine draws in a mixture of air and fuel. The compression stroke then compresses this mixture, leading to ignition during the power stroke, which generates energy to move the piston. After the power stroke, the exhaust stroke expels the spent gases from the combustion process. This cycle repeats continuously, making four-stroke engines efficient and commonly used in vehicles, motorcycles, and lawn equipment. They are known for their durability and fuel efficiency compared to two-stroke engines.