diffusers 35 and 36 each extend over approximately half of the circumference however the area ratio can be varied depending on the desired maximum airflow through each diffuser in fig7 a schematic representation of the coupling of a vde with the inventive compressor is shown engine 43 comprises a first group of cylinders 44 and a second group of cylinders 45 with the second group of cylinders 45 capable of being deactivated a turbocharger 46 includes a turbine 46 and a compressor 48 driven by turbine 47 compressor 48 comprises a first outlet 49 which is connected through a fluid here air conduit 50 to the first group of cylinders 44 and a second outlet 51 which is connected through a fluid here air conduit 52 to the second group of cylinders 45 a valve 53 is arranged in first fluid conduit 50 and a valve 54 is arranged in second fluid conduit 52 both valves 53 and 54 are capable of controlling the airflow through their respective fluid conduits separately exhaust gases from cylinders 44 and 45 are exhausted into exhaust manifold 55 through turbine 47 of turbocharger 46 when the second group of cylinders 45 is deactivated airflow in the second fluid conduit 52 is automatically interrupted so that all the airflow in compressor 48 exits through first outlet 49.