What is known as the period when your intake and exhaust valves are both open during scavenging?

What is known as the period when your intake and exhaust valves are both open during scavenging?

• A. Valve timing
• B. Valve lift
• C. Valve overlap
• D. Scavenging phase

Answer: (C)

Overlap is the interval in the valve timing cycle when both the intake and exhaust valves are open at the same time. This happens as the engine transitions from exhaust to intake, typically toward the end of the exhaust stroke and the start of the intake stroke. During this window, exhaust gases are still leaving while fresh air-fuel mix begins to enter, creating scavenging that helps push out spent gas and improve cylinder filling for the next power stroke. The size and position of this overlap are controlled by camshaft timing and valve lift—more timing duration and higher lift extend the overlap. Valve timing describes the overall opening/closing schedule, valve lift is how far the valves move, and scavenging is the general process of clearing exhaust and filling the cylinder. The period when both valves are open is specifically valve overlap.

Overlap is the interval in the valve timing cycle when both the intake and exhaust valves are open at the same time. This happens as the engine transitions from exhaust to intake, typically toward the end of the exhaust stroke and the start of the intake stroke. During this window, exhaust gases are still leaving while fresh air-fuel mix begins to enter, creating scavenging that helps push out spent gas and improve cylinder filling for the next power stroke. The size and position of this overlap are controlled by camshaft timing and valve lift—more timing duration and higher lift extend the overlap. Valve timing describes the overall opening/closing schedule, valve lift is how far the valves move, and scavenging is the general process of clearing exhaust and filling the cylinder. The period when both valves are open is specifically valve overlap.