In a four-stroke engine, how does the camshaft speed compare to the crankshaft speed?

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Multiple Choice

In a four-stroke engine, how does the camshaft speed compare to the crankshaft speed?

Explanation:
In a four-stroke engine, valve events are timed to occur once for every two crankshaft revolutions. A full engine cycle (intake, compression, power, exhaust) spans 720 degrees of crankshaft rotation, which is two full turns. The camshaft, which operates the intake and exhaust valves, completes one revolution during that same cycle. Therefore the camshaft must rotate at half the crankshaft speed. This 2:1 ratio ensures valves open and close at the correct times relative to piston position. If the camshaft turned at the same speed as the crankshaft, valve timing would be off and the engine wouldn’t run properly.

In a four-stroke engine, valve events are timed to occur once for every two crankshaft revolutions. A full engine cycle (intake, compression, power, exhaust) spans 720 degrees of crankshaft rotation, which is two full turns. The camshaft, which operates the intake and exhaust valves, completes one revolution during that same cycle. Therefore the camshaft must rotate at half the crankshaft speed. This 2:1 ratio ensures valves open and close at the correct times relative to piston position. If the camshaft turned at the same speed as the crankshaft, valve timing would be off and the engine wouldn’t run properly.

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