During the compression stroke of a 4 cycle engine, what happens to the intake valve?

During the compression stroke of a 4-cycle engine, the intake valve closes. This is a critical phase in the engine's operation. At the beginning of the compression stroke, the piston moves upward in the cylinder, compressing the air-fuel mixture that was drawn into the cylinder during the previous intake stroke. The closure of the intake valve ensures that the compressed mixture is sealed within the combustion chamber, allowing for efficient ignition and combustion when the spark plug fires.

If the intake valve were to remain open during this stroke, it would disrupt the compression process by allowing the mixture to escape, leading to loss of pressure and power output. The timing of the valve operations is crucial for the engine's performance, and the closure of the intake valve at the start of the compression stroke is essential for creating the optimal conditions for combustion.