Which of the following are the strokes of the engine?

In the context of engine operation, the strokes typically referred to are those related to the cycles that occur within a combustion engine. The power and combustion strokes are crucial because they represent the key phases of the four-stroke cycle in internal combustion engines.

During the power stroke, a fuel-air mixture is ignited, causing a rapid expansion of gases that pushes the piston down, generating power that ultimately turns the crankshaft. The combustion process is essential for this power generation.

Other phases of the engine cycle, such as intake and exhaust, primarily deal with the movement of gases in and out of the combustion chamber, while compression involves the squishing of the fuel-air mixture before ignition occurs, and expansion refers to the phase after combustion where gases expand, exerting force. Idle and acceleration describe states of engine operation rather than specific strokes of the engine cycle. Therefore, identifying power and combustion as the strokes reflects an understanding of the central elements that drive engine performance.