Reciprocating internal combustion engine
Unconventional engines - Internal combustion thermal motors

The layout and number of cylinders in a reciprocating engine depend on the application and the resulting technological and economic constraints (figure 1 ). The engine's power is a function of its cubic capacity, which is defined by the associated bore, stroke and number of cylinders. For a given engine, the increase in performance is linked to the increase in torque and rotational speed, but the laws of similarity show that there is a majorant in terms of mass and maximum permissible rpm.