Discuss why the idealized cycles of Exercises 7.20 and 7.21 are inadequate for the analysis of real engines. Which idealizations are likely to be the weakest? What effects will they have on the predicted performance?

Data From in Exercise 7.20

An ideal diesel cycle using air as the working fluid has a compression ratio of 15. The energy input is idealized as a transfer of energy as heat to the working fluid of 1650 kJ/kg. The inlet conditions are 20°C and 1 bar. Calculate the temperature and pressure of all remaining states in the cycle, and determine the cycle efficiency.

Data From in Exercise 7.21

The compression ratio of an ideal Otto cycle using air as the working fluid is 8. The energy input is idealized as a transfer of energy as heat to the working fluid of 1650 kJ/kg. The inlet conditions are 20°C and 1 bar. Calculate the temperature and pressure of all remaining states in the cycle, and determine the cycle efficiency.