The crank angle is defined as:

• A. The same as crankshaft rotation
• B. The same as camshaft rotation
• C. The same as piston position
• D. The same as throttle position

Answer: (A)

Crank angle is a measure of how far the crankshaft has rotated, usually expressed in degrees from a reference position such as top dead center. This angular measure directly represents the crankshaft’s rotation and is used to time events like ignition and valve opening relative to piston position. The camshaft typically turns at about half the crankshaft speed in a four-stroke engine, so its rotation is not the same as the crank angle. Piston position is linked to crank angle but is not itself an angular measure, and throttle position has no direct relation to the crank’s rotation. So the crank angle is defined as the rotation of the crankshaft.