Reciprocating-piston internal combustion engine with a device for adjusting the angle of the camshafts relative to one another

The invention relates to a reciprocating-piston internal combustion engine with at least one piston-cylinder unit, the working space of which has at least one intake valve and at least one exhaust valve, the valves being actuable by means of cams which are provided on separate camshafts assigned to the respective valves, and with a device for adjusting the angle of the camshafts relative to one another, the said device being arranged between the crank shaft of the internal combustion engine and the camshafts driven by the crank shaft, and having a planetary gear mechanism. In order to achieve an alteration of the intake valve opening times for the purpose of increasing efficiency and saving fuel, the planetary gear mechanism (1) should have a sun gear (5), driven by the crank shaft, which meshes with at least one set of planet gears (6) which drive an annular gear (8) connected in drive terms to the camshaft (2, 3) assigned to the intake valves, and, to alter the intake-valve closing time, the planet gears (6) should be arranged to allow them to be pivoted periodically about the central axis (12).