Abstract: The invention relates to an internal combustion engine comprising a plurality of subunits which each comprise a crankshaft part, at least one piston being accommodated on a crank of each crankshaft part by means of a connecting rod, wherein at least one first subunit is permanently operated while the internal combustion engine is operating, and at least one additional subunit can be switched off. To switch off a subunit and to disconnect the crankshaft parts from each other, the crankshaft parts of at least one first subunit and an adjacent second subunit that can be switched off are connected to each other in a rotationally locked manner and can move relative to each other with respect to the rotational axes thereof in such a way that a rotational motion applied to the crankshaft part of the second subunit by the crankshaft part of the first subunit is substantially suspended.