Abstract: In a reciprocating piston internal combustion engine, an upwardly arcuately shaped combustion space is formed in the cylinder head, which contains suspended valves arranged V-shaped. The valves are moved as close as possible to the combustion space boundary and form narrow spaces with respect thereto. The radii of the transitional arcs from the valve-end faces to the combustion space boundary increase continuously from the narrow spaces in both circumferential directions of the combustion space boundary and reach their maximum values in the center plane between the valves. The combustion space curvature is matched to the predetermined angles of inclination of the valves.