USCG Exam PracticeDiesel engine principles (motor propulsion)
In a four-stroke diesel engine, the camshaft is geared to run at what speed relative to the crankshaft?
- A. The same speed as the crankshaft
- ✓ Half the crankshaft speedCorrect
- C. Twice the crankshaft speed
- D. One-quarter the crankshaft speed
Why B is correct
In a four-stroke cycle, each cylinder fires once every two crankshaft revolutions, so the camshaft is geared to run at half crankshaft speed to time the valves correctly. DOE-HDBK-1018 Vol.1 §1-1 states this directly.
Cited:DOE-HDBK-1018 Vol.1 §1-1