What is released during the exhaust stroke of a four-stroke engine?

During the exhaust stroke of a four-stroke engine, the main function is to expel the gases that resulted from the combustion of the air-fuel mixture in the previous power stroke. This process involves the exhaust valves opening, allowing the burnt gases, which are often referred to as "exhaust gases" or "exhaust" after the fuel has been combusted, to exit the combustion chamber.

This is a crucial step in the four-stroke cycle as it prepares the engine for the next intake stroke. The combustion process produces a mix of gases, including carbon dioxide, nitrogen, and water vapor, which all need to be removed from the cylinder to make room for fresh air and fuel in the next cycle. Therefore, the release of exploded gases during the exhaust stroke is a key aspect of engine efficiency and performance, ensuring that the engine can function properly in subsequent strokes.