Are both valves open during the exhaust stroke?

During the exhaust stroke of a four-stroke internal combustion engine, the exhaust valve opens to allow the spent gases to exit the combustion chamber after the power stroke. However, the intake valve remains closed during this stroke. The design of the engine ensures that only one valve is open at a time during the exhaust process to efficiently push out the exhaust gases without allowing fresh air-fuel mixture to enter the cylinder prematurely.

Hence, the correct response identifies that both valves are not open at the same time during the exhaust stroke, thus confirming that the statement is false. Understanding the sequence of events in a four-stroke cycle is crucial for diagnosing engine performance and ensuring proper operation.