Optimal Stroke Path for Reciprocating Heat Engines

Figure 8

Example of sensitivity of optimal piston motion to compression ratio r, for internally dissipative friction. Maximum nondimensional piston parameter = 1. Frictional exponent m = 2. Plots are for (1) conventional motion; (2) optimal motion with r = 3; (3) optimal motion with r = 8. The abscissa is time divided by stroke time (t/), and the ordinate is piston velocity relative to its maximum value for the conventional trajectory.