4.13. A diesel engine has a compression ratio of 22:1. The conditions in the cylinder at...

Transcribed Image Text:

4.13. A diesel engine has a compression ratio of 22:1. The conditions in the cylinder at the start of compression are p = 101.3 kPa and T = 325 K. Calculate the pressure and temperature at the end of compression, assuming the compression process is isentropic: (a) Assume the cylinder contains an ideal gas with y = 1.4 and R = 287 J/kg.K. (b) Assume the cylinder contains air which may be regarded as a semiperfect gas (use the gas tables). (c) Compare the work of compression in (a) and (b) above. In practice, heat losses reduce the final compression temperature by 100 K. For a diesel engine operating at an equivalence ratio of 0.75 (full load): (d) Calculate the ratio of heat loss during compression to the fuel energy added per cycle. 4.13. A diesel engine has a compression ratio of 22:1. The conditions in the cylinder at the start of compression are p = 101.3 kPa and T = 325 K. Calculate the pressure and temperature at the end of compression, assuming the compression process is isentropic: (a) Assume the cylinder contains an ideal gas with y = 1.4 and R = 287 J/kg.K. (b) Assume the cylinder contains air which may be regarded as a semiperfect gas (use the gas tables). (c) Compare the work of compression in (a) and (b) above. In practice, heat losses reduce the final compression temperature by 100 K. For a diesel engine operating at an equivalence ratio of 0.75 (full load): (d) Calculate the ratio of heat loss during compression to the fuel energy added per cycle.