USCG Exam PracticeDiesel engine principles (motor propulsion)
In a four-stroke diesel engine, what is the correct sequence of piston strokes beginning with the intake stroke?
- ✓ Intake, compression, power, exhaustCorrect
- B. Intake, power, compression, exhaust
- C. Compression, intake, power, exhaust
- D. Intake, compression, exhaust, power
Why A is correct
The four-stroke cycle proceeds: intake (piston down, intake valve open), compression (both valves closed, piston rises), power (fuel injected and ignited, piston driven down), exhaust (exhaust valve open, piston rises to expel gases). This sequence requires two crankshaft revolutions to complete one power stroke per cylinder.
Cited:DOE-HDBK-1018 Vol.1 §1-1