Patent ID: 7870731

Claim:
An exhaust gas turbocharger for an internal combustion engine, including a turbine ( 3 ) with a turbine wheel ( 28 ), a compressor ( 5 ) with a compressor wheel ( 16 ) rotationally fixedly connected by means of a shaft ( 7 ) to the turbine wheel ( 28 ), the compressor ( 5 ) having a variable compressor inlet geometry comprising a plunger ( 33 ) and a sleeve-like partition ( 31 ) movably supported so as to partially or completely open or close an auxiliary duct ( 29 ) extending radially to the compressor wheel ( 16 ), the compressor wheel ( 16 ) having compressor wheel blades ( 18 ) with an axial inlet area ( 36 ) and a radial wheel inlet area ( 19 ) for receiving air from the auxiliary duct ( 29 ), said compressor wheel ( 16 ) including a contoured ring ( 17 ) provided at its outer surface with auxiliary blades ( 20 ) so as to be arranged over the compressor wheel blades ( 18 ) the contoured ring ( 17 ) extending axially over at least a part of the radial and of the axial wheel inlet areas ( 19 , 36 ) of the compressor wheel ( 16 ), the auxiliary blades ( 20 ) being attached to an outer lateral surface ( 21 ) of the contoured ring ( 17 ) so as to merge at their downstream ends with the compressor wheel blades ( 18 ), and, in a longitudinal section through the contoured ring ( 17 ), the outer lateral surface ( 21 ) of the contoured ring ( 17 ) having one of a rectilinear form, a curved, concave form and a partially rectilinear and a partially curved form.