Diesel cycle performance modeling for three different cases of specific heat capacities

In this work the performance of standard air Diesel cycle has been compared for three different cases of specific heat capacity. The performance of irreversible Diesel cycle is studied by finite time thermodynamics. Two cases of specific heat capacities of the working fluid, being temperature and also temperature and compression ratio dependent are derived and then compared with temperature dependent specific heats capacity of the working fluid, result of paper of Ge et al. (2008). In this model, nonlinear relation between the specific heats of working fluid and its temperature as well as its temperature and compression ratio, irreversibility results of compression and expansion efficiency and cutoff ratio are considered. The relation of the power output with compression ratio were derived for three cases of specific heats capacity. The maximum power output achieved in the case that the heat capacity of working fluid is function of both temperature and compression ratio are more than those cases of in which heat capacity is a function of temperature only. As well as the results show that the maximum power output achieved in the case that the temperature dependent specific heat capacity of working fluid, is correspond topaper of Ge et al. (2008) are more than those case of in which heat capacity of working fluid, being temperature dependent result of this paper. The result can be used to survey and compare the maximum power output for three cases. The maximum power output decrease as the cutoff ratio and internal irreversibility increase.