STEP 3 To review the efficiency of ideal heat engines operating on the Otto and Diesel cycles, you are asked to perform the following branches: • Provide general plot(s) for thermal efficiency, O vs compression ratio, r for ideal Otto and diesel engines and show the typical compressions ratios. Compare your plots in terms of the typical compression ratio values. • Using your plot of the thermal efficiency, O vs compression ratio, r for ideal diesel engine, show how will the thermal efficiency of the diesel engine, O would change with the cut-off ratio values. • Explain mathematically how the thermal efficiency, D of Otto cycle is always higher than diesel cycle if-and-only-if both engines are operated at the same compression ratio, D. • Based on your previous answer, indicate why we use diesel engines. • Conclude your results of step 3 in two sentences.

STEP 3 To review the efficiency of ideal heat engines operating on the Otto and Diesel cycles, you are asked to perform the following branches: • Provide general plot(s) for thermal efficiency, O vs compression ratio, r for ideal Otto and diesel engines and show the typical compressions ratios. Compare your plots in terms of the typical compression ratio values. • Using your plot of the thermal efficiency, O vs compression ratio, r for ideal diesel engine, show how will the thermal efficiency of the diesel engine, O would change with the cut-off ratio values. • Explain mathematically how the thermal efficiency, D of Otto cycle is always higher than diesel cycle if-and-only-if both engines are operated at the same compression ratio, D. • Based on your previous answer, indicate why we use diesel engines. • Conclude your results of step 3 in two sentences.

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter9: Heat Transfer With Phase Change

Section: Chapter Questions

Problem 9.4DP

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