Figure 11. p-v diagram for three types of rolling piston heat engines: Carnot heat engine, one-valve heat engine, and valve-less heat engine

From

Quasi Isothermal Heat Engine for Concentrating Solar Power Systems

E. Kussul, T. Baidyk, O. Olvera Tapia

American Journal of Energy Research. 2016, 4(1), 16-26 doi:10.12691/ajer-4-1-3