 comprising: an assembly arrangement having at least one auxiliary assembly and an electric machine which is configured independently of a drive unit of the motor vehicle, the electric machine being configured for operation as a motor for driving the at least one auxiliary assembly and as a generator for generating electric power, an auxiliary engine configured as an internal combustion engine which is releasably fastened via an interface to the assembly arrangement to provide rotational drive moment to at least one of the at least one auxiliary assembly and the electric machine.  00. 