Comparative analysis of the Atkinson and the Otto cycles with heat transfer, friction and variable specific heats of working fluid

In this article, the performance of air standard Atkinson and Otto cycles with irreversibility factors, i.e. efficiencies of compression and expansion processes, heat transfer loss, friction-like term loss and variable specific heats of working fluid is analyzed using finite-time thermodynamics. The relations between the power output and the compression ratio and between the thermal efficiency and the compression ratio of the cycle are derived by detailed numerical examples. Moreover, the effects of heat transfer loss, the friction-like term loss and variable specific heats of working fluid on the cycle performance are analyzed. The results show that the effects of heat transfer loss, friction and variable specific heats of working fluid on the irreversible cycle performance should be considered in cycle analysis.