In a two-stroke cycle engine, compression and intake events occur at the same time.

In a two-stroke cycle engine, compression and intake events occur at the same time.

• A. True
• B. False
• C. Only during exhaust
• D. Only during scavenging

Answer: (A)

In a two-stroke engine, there isn’t a separate intake stroke. The fresh air-fuel charge is admitted and then compressed within the same crank angle range as the compression event. As the piston moves toward top dead center, the intake/transfer paths open at the right times (via ports or a crankcase scavenging system), allowing fresh charge to enter and begin to be compressed as the piston continues upward. That overlap—intake happening during the same stroke as compression—is what makes the statement true. In contrast, four-stroke engines have distinct strokes for intake and compression, which is why this overlap isn’t present there.

In a two-stroke engine, there isn’t a separate intake stroke. The fresh air-fuel charge is admitted and then compressed within the same crank angle range as the compression event. As the piston moves toward top dead center, the intake/transfer paths open at the right times (via ports or a crankcase scavenging system), allowing fresh charge to enter and begin to be compressed as the piston continues upward. That overlap—intake happening during the same stroke as compression—is what makes the statement true.

In contrast, four-stroke engines have distinct strokes for intake and compression, which is why this overlap isn’t present there.