To use two-cylinder piston without first running in hot cylinder called a "plunger (piston Displacer)", and the two options are located in the cylinder bore, piston, called "cool power (Power piston)."
Use two-piston by the piston in the cylinder, the first work called hot. "Piston punching (Displacer piston)" and a second piston in a cylinder called a "piston force (Power piston)".
To use 2 piston. The first piston working cylinder hot called "piston chase (Displacer piston)", and that 2 piston in cylinder cold call "The piston"s (Power piston)."