Patent ID: 7444814

Claim:
A method for operating an internal combustion engine having an air induction and an exhaust gas system, a compressor with a compressor housing and a compressor wheel ( 102 ) rotatably mounted in the compressor housing disposed in the induction system for compressing combustion air to an increased boost pressure, the compressor housing having an intake duct and an auxiliary duct ( 115 ) extending to the compressor intake duct ( 105 ) and being in communication therewith via an opening region ( 116 ) formed adjacent the compressor wheel ( 102 ), an adjustable blocking element ( 109 ) arranged in the compressor intake duct ( 105 ) upstream of the compressor wheel ( 102 ), an adjustable swirl device ( 114 , 117 ) arranged in the opening region ( 116 ) of the auxiliary duct ( 115 ) into the compressor intake duct ( 105 ), and an NO x storage catalytic converter ( 12 ) arranged in the exhaust gas system, the swirl device ( 114 , 117 ) being movable to a position in which combustion air is directed onto the compressor wheel so as to produce a propulsive swirl, and simultaneously the blocking element ( 109 ) being movable to a position in which the air supply to the compressor intake duct ( 105 ) is restricted in order to generate an air fuel ratio (λ) having a relative surplus of fuel, said method comprising the steps of restricting the air supply to the compressor wheel ( 102 ), and applying to the compressor wheel ( 102 ) simultaneously a propulsive swirl of combustion air while keeping the fuel supply at least approximately constant in order to reduce NO x emissions.