Patent ID: 8191367

Claim:
A turbocharger comprising: a center housing ( 22 ) containing a bearing assembly and a rotary shaft ( 26 ) mounted in the bearing assembly; a compressor wheel ( 24 ) affixed to one end of the shaft ( 26 ); a turbine wheel ( 40 ) affixed to an opposite end of the shaft ( 26 ) and disposed in a bore ( 44 ) of a turbine housing ( 38 ) that is coupled to an opposite side of the center housing ( 22 ), the turbine housing ( 38 ) defining a chamber ( 42 ) surrounding the turbine wheel ( 40 ) for receiving exhaust gas to be directed into the turbine wheel ( 40 ); and a sliding piston cartridge ( 50 , 50 ′, 150 )) comprising: a carrier ( 52 , 52 ′, 152 ) inserted axially into the bore ( 44 ) of the turbine housing ( 38 ) with a radially outer surface of the carrier ( 52 ) engaging an inner surface of the bore ( 44 ), the carrier ( 52 , 52 ′, 152 ) having a tubular portion ( 54 ) defining a central bore therethrough substantially coaxial with the turbine housing bore ( 44 ), the tubular portion ( 54 ) having an upstream end and a downstream end with respect to a flow direction of exhaust gas through the central bore, the carrier ( 52 , 52 ′, 152 ) further comprising an array of circumferentially spaced vanes ( 58 ) axially projecting from the upstream end of the tubular portion ( 54 ), the vanes ( 58 ) having fixed ends joined to the tubular portion ( 54 ) and free ends that are adjacent a wall ( 60 ) of the turbine housing ( 38 ), the tubular portion ( 54 ) defining circumferentially spaced openings ( 66 ) downstream of the fixed ends of the vanes ( 58 ), connecting portions ( 72 , 58 ′) being defined between the openings ( 66 ), the vanes ( 58 ) defining a first nozzle portion and the circumferentially spaced openings ( 66 ) and connecting portions ( 72 , 58 ′) defining a second nozzle portion for directing exhaust gas from the chamber into the turbine wheel ( 40 ); and a tubular piston ( 62 , 62 ′, 162 ) disposed in the central bore of the carrier ( 52 , 52 ′, 152 ) such that the piston ( 62 , 62 ′, 162 ) is axially slidable relative to the carrier ( 52 , 52 ′, 152 ) between a closed position and an open position, the piston ( 62 , 62 ′, 162 ) in the closed position substantially blocking exhaust gas from passing through the second nozzle portion to the turbine wheel ( 40 ), the piston ( 62 , 62 ′, 162 ) progressively unblocking the second nozzle portion as the piston ( 62 , 62 ′, 162 ) travels toward the open position.