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Diesel vs. Otto cycle efficiency: limiting behavior with cut-off ratio State when the Diesel cycle efficiency approaches the Otto cycle efficiency. Choose the correct condition.

Difficulty: Medium

Cut-off is increased
Cut-off is decreased
Cut-off is zero
Cut-off is constant

Correct Answer: Cut-off is zero

Explanation:

ConceptDiesel cycle has heat addition at constant pressure with a finite cut-off ratio r_c. As r_c → 1 (i.e., cut-off → 0), the Diesel cycle heat addition tends to constant volume, and the cycle approaches the Otto cycle.

Final AnswerCut-off is zero

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