What is the process of supplying a diesel engine cylinder with air at a pressure greater than atmospheric called?

The correct answer is supercharging, which refers to the process of supplying a diesel engine cylinder with air at a pressure greater than atmospheric levels. In supercharging, a mechanical device, known as a supercharger, compresses air before it enters the engine's cylinders. This additional air allows for a greater amount of fuel to be burned, which enhances the engine's power output and efficiency.

This process contributes to the overall performance of the engine by improving combustion and maximizing the amount of energy derived from the fuel. Supercharging is commonly used in various types of engines, including marine diesel engines, to augment power without necessarily increasing engine size or weight.

While hypercharging and turbocharging are related concepts, they refer to different methods of increasing air supply. Hypercharging typically implies even higher levels of compression than standard supercharging, often involving complex systems. Turbocharging, on the other hand, involves using exhaust gases to spin a turbine that compresses incoming air. Overcompression could describe a detrimental condition rather than a defined process used in engine performance enhancement, and does not specifically address the mechanism of air supply.