to perform a boost and or assist function by means of the additional power input with no additional transmission ratio being provided by the planetary gearset 38 in this case the electric machine 30 can also be operated as a generator allowing some of the power of the internal combustion engine 12 to be fed into the electric machine 30 with no additional transmission ratio being provided by the planetary gearset 38 in this case in this case the auxiliary units 54 56 are driven by the internal combustion engine 12 via the intermediate shaft 46 and the auxiliary shaft 50 for purely electric operation the first clutch k 1 and the second clutch k 2 are open while the third clutch k 3 is closed in purely electric operation the internal combustion engine 12 is switched off and can be started in a simple manner during electric operation by closing the first clutch k 1 or the second clutch k 2 during this process the third clutch k 3 can remain closed until the internal combustion engine 12 has been started and or the transmission clutch 14 is to be closed when the first clutch k 1 the second clutch k 2 and the third clutch.