A plot of Eq. (4) with pressure ratio as the independent variable is seen in Fig. 3 for several temperature ratios. There is a clear optimum pressure ratio for each temperature ratio that corresponds to maximum non-dimensional net work output. As temperature ratio increases, the optimum pressure ratio and corresponding (maximum) net work output increase as well. In addition, each temperature line decays to zero at very large pressure ratios. This implies that there exists a maximum pressure ratio for which there is zero net work output.