Understanding the Relationship
* Camshaft vs. Crankshaft: In a four-stroke engine, the crankshaft makes two full revolutions (720 degrees) for every one full revolution of the camshaft (360 degrees). This is because the engine cycle (intake, compression, power, exhaust) takes four strokes, but only two crankshaft rotations.
Calculating the Camshaft RPM
1. Crankshaft Speed: You're given the crankshaft speed as 5500 RPM.
2. Camshaft Speed: Since the camshaft turns half as fast as the crankshaft, divide the crankshaft speed by 2:
Camshaft RPM = Crankshaft RPM / 2
Camshaft RPM = 5500 RPM / 2
Camshaft RPM = 2750 RPM
Therefore, the camshaft turning rate is 2750 RPM when the four-cylinder engine is operating at 5500 RPM.
