When a compressor piston is at the top of its stroke, what is the position of the valves?

When the compressor piston reaches the top of its stroke, it is in the position known as 'top dead center.' At this point, the compressed gas has been pushed out of the cylinder, and the pressure inside the cylinder is at its peak.

The function of the valves in a compressor is crucial for regulating the flow of refrigerant. At the top of the stroke, the compressor has completed exhausting the gas to the discharge line, which means that there is no need for the suction valve to be open since there is no new refrigerant entering the chamber. Similarly, the discharge valve must be closed at this moment to prevent backflow of the refrigerant into the cylinder.

Thus, both the suction and discharge valves are closed, preventing gas from both entering and exiting the cylinder, which is essential for maintaining the compression cycle's integrity and efficiency. This scenario ensures that the compressor can effectively create a low-pressure area during the downward stroke, allowing new refrigerant to be injected in the next cycle.