Which is one of the four strokes in an internal combustion engine?

• A. Intake stroke
• B. Compression stroke
• C. Exhaust stroke
• D. Power stroke

Answer: (C)

The four-stroke cycle governs how most internal combustion engines operate. The exhaust stroke is the phase that comes after the power stroke. As the piston moves upward in the cylinder, the exhaust valve opens and pushes the burned gases out through the exhaust port into the exhaust system. This clearing of the cylinder makes room for a fresh air–fuel charge to be drawn in during the next intake stroke. So the exhaust stroke is one of the four strokes—the others are intake, compression, and power—that together complete each engine cycle.