What part of the vehicle’s engine cycle is known as the intake stroke?

The intake stroke is characterized by the downward motion of the piston within the cylinder of an engine. During this phase, the piston moves down, which creates a vacuum that allows air and fuel mixture to flow into the combustion chamber. This process is critical to the engine's operation because it fills the cylinder with the air-fuel mixture that is needed for combustion in the next stroke.

In contrast, the other phases of the engine cycle are distinct in their functions. For example, the upward motion of the piston is associated with the compression stroke, where the air-fuel mixture is compressed to prepare for ignition. The exhaust process involves expelling the combustion gases from the cylinder when the piston rises, and the compression process specifically relates to the phase where the mixture is being compressed before igniting. Each of these strokes plays a distinct role in the engine cycle, making the intake stroke specifically linked to the downward movement of the piston.