This cycle describes the functioning of a reciprocating piston engine used in automobile engines. This cycle consists of two adiabatic and two isochoric steps. The thermal efficiency of this cycle is: η = 1 – r(1 – γ), where r is the compression ratio and γ is the specific heat ratio, which is 1.4 for air in the present simulation. The four steps are plotted in the PV (pressure vs. volume) and TS (temperature vs. entropy) diagrams. The adiabatic and isochoric transformations are in blue and red, respectively. The areas in the PV and TS diagrams are equal to the net work and to the net heat transfer, respectively. These two quantities are equal. You can set the values of the heat source temperature, the heat sink temperature, and the compression ratio.