What happens to the combustion pressure without a functional compression ring?

The combustion pressure is directly influenced by the integrity of the compression ring in an engine's cylinder. The compression ring is responsible for sealing the combustion chamber, ensuring that the pressure generated during the combustion process is effectively contained.

When the compression ring is not functioning correctly or is missing, the combustion chamber cannot contain the pressure that is generated when the fuel-air mixture ignites. This leads to a loss of pressure, as gases can escape past the piston instead of being forced to push the piston down for power generation. Therefore, without a functional compression ring, the combustion pressure is lost, significantly affecting engine performance, efficiency, and power output.

The other answers suggest various outcomes that do not accurately reflect the mechanical function of the compression ring, which is crucial for maintaining the high-pressure environment necessary for effective combustion.