Air-standard Diesel cycle: effect of cut-off ratio on efficiency For a fixed compression ratio, how does the thermal efficiency of the Diesel cycle vary with the cut-off ratio? Choose the correct trend.
Mechanical Engineering
Thermodynamics
Difficulty: Medium
Choose an option
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Adecrease in cut-off
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Bincrease in cut-off
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Cconstant cut-off
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Dnone of these
Answer
Correct Answer: decrease in cut-off
Explanation
ConceptDiesel cycle efficiency (for fixed compression ratio) decreases as the cut-off ratio rc increases, because more heat is added at higher temperatures with less effectiveness. Thus, η increases as rc decreases.
Final Answerdecrease in cut-off