Internal combustion engine

An internal combustion engine is provided having a common engine transmission housing having a crankcase chamber in which a crankshaft having a longitudinal central axis is rotatably accommodated and a transmission chamber in which a shift transmission is accommodated, and having a longitudinal axis and a vertical axis extending transversely to the longitudinal central axis of the crankshaft, the engine transmission housing has at least one working cylinder with a piston working surface and a working piston which can move in the working cylinder along the piston working surface, the working piston is connected with the crankshaft through a connecting rod, and the engine transmission housing has a clutch accommodating chamber in which a clutch device is arranged and a rotor accommodating chamber in which a generator device is arranged, the working piston has a piston head, which has a top surface facing the combustion chamber and a bottom surface facing the crankcase chamber, and the internal combustion engine