Which stroke in a two-stroke engine is responsible for exhausting gases?

In a two-stroke engine, the exhaust stroke is crucial for expelling the burned gases that result from combustion. This occurs after the power stroke, where fuel is ignited to create energy. During the exhaust stroke, the engine's piston moves upward, forcing the spent gases out of the combustion chamber and allowing fresh air-fuel mixture to enter.

The unique design of two-stroke engines allows for this process to happen more quickly than in four-stroke engines, where the exhaust and intake strokes are separate. In this case, the rotational motion of the crankshaft continuously moves the piston and relies heavily on port timing—where exhaust and intake ports open and close at specific times during the piston's travel—to efficiently cycle through the necessary strokes.

Understanding this mechanism is integral to grasping how two-stroke engines operate. The function of other strokes in a two-stroke engine, like the power and compression strokes, revolves around generating power and compressing the fuel-air mixture, but it is the exhaust stroke that specifically deals with the removal of gases.