Method and control device for determining shut-off of a combustion engine

The engine (1) has a control unit (4) and is coupled to an electrical machine (2) acting as starter/generator, with control unit (5) and sensor unit to detect rotor RPM of the machine. The machine is in active connection with the drive shaft of the engine via a belt drive (3). Drive shaft RPM is calculated via a known transmission ratio, from the rotor RPM, and engine coasting is recognized, when drive shaft RPM is within a tolerance area of zero RPM. The sensor unit consists of three Hall sensors, positioned at 120[deg] coaxial to a stator of the machine.