Internal combustion engine

The internal combustion engine incorporates a cylinder block (10) and a main rotor (20). The cylinder block contains a cylinder (101) circular in cross-section, with a ring-shaped valve seat (102) with slightly less diameter along an area of the cylinder wall (1011). The valve seat has at least one radially outwardly extending section (b), which can limit the valve seat in relation to the area of the cylinder wall outside the valve seat. The valve seat has an ignition system (11), an outlet (12) and an air inlet (13). The main rotor has a ring-shaped component installed concentrically in the cylinder and a shaft (201) is provided, arranged centrally, so that it can rotate freely when it is suspended in a suspension (14) on both sides of the cylinder block.