Question

In a four stroke cycle diesel engine, compression __________

(a) starts at 40º after bottom dead center and ends at 10º before top dead center

(b) starts at 40º before top dead center and ends at 40º after bottom dead center

(c) starts at top dead center and ends at 40º before bottom dead center

(d) may start and end anywhere

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Answer 1

Answer: (a) starts at 40º after bottom dead center and ends at 10º before top dead center

Explanation: In a four-stroke diesel engine, compression begins shortly after bottom dead center (BDC) and continues until just before top dead center (TDC). Typically, compression starts around 40º after BDC and ends approximately 10º before TDC, as the piston compresses the air-fuel mixture before ignition occurs.