Alternative Approach for predicting the performance of Irreversible Otto Cycle

The performance of an air-standard Otto cycle with variation of cycle peak temperature and variable specific heats of working fluid is analyzed. The relations between the power output and the compression ratio, between the thermal efficiency and the compression ratio, as well as the optimal relation between power output and the efficiency of the cycle are derived by detailed numerical examples. Moreover, the effects cycle peak temperature and variable specific heats of working fluid on the cycle performance are analyzed. The results show that the effects of cycle peak temperature and variable specific heats of working fluid on the cycle performance are obvious, and they should be considered in practice cycle analysis. The results obtained from this work are presented in the form of generalized equations for specific work output in term of compressor efficiency, turbine efficiency and compression ratio of the cycle. These equations can be used by the designers for predicting the performance of real otto cycle. The results obtained in this paper may provide guidance for the design of practice internal combustion engines.