The compression ratio of an engine is 10 and the temperature and pressure at the start of compression is 37 ◦ C and 1 bar. The compression and expansion processes are both isentropic and the heat is...

The compression ratio of an engine is 10 and the temperature and pressure at the start

of compression is 37
^◦C and 1 bar. The compression and expansion processes are both

isentropic and the heat is rejected at exhaust at constant volume. The amount of heat

added during the cycle is 2730 kJ/kg. Determine the mean effective pressure and thermal

efficiency of the cycle if (i) the maximum pressure is limited to 70 bar and heat is added

at both constant volume and constant pressure and (ii) if all the heat is added at constant

volume. In this case, how much additional work per kg of charge would be obtained if

it were possible to expand isentropically the exhaust gases to their original pressure of 1

bar. Assume that the charge has the same physical properties as that of air.