Turbocharger having a meridionally divided turbine housing and a variable turbine nozzle

A turbocharger having a meridionally divided variable-nozzle turbine, comprising:

• a turbine comprising a turbine housing and a turbine wheel mounted in the turbine housing and connected to a rotatable shaft for rotation therewith, the turbine housing defining a meridionally divided scroll extending circumferentially and surrounding the turbine wheel, the meridionally divided scroll defining a first scroll extending substantially fully about the turbine wheel and a separate second scroll extending substantially fully about the turbine wheel;
• the turbine housing defining a separate inlet for each of the first and second scrolls through which separate first and second exhaust gas streams are received;
• a nozzle leading from the meridionally divided scroll generally radially inwardly to the turbine wheel;
• a compressor comprising a compressor housing and a compressor wheel mounted in the compressor housing and connected to the rotatable shaft for rotation therewith;
• a center housing connected between the compressor housing and the turbine housing and containing bearings for the shaft;
• a generally annular nozzle ring having a first face that comprises one wall of the nozzle and that is axially spaced from an opposite wall of the nozzle;
• a shroud plate mounted within the nozzle, the shroud plate meridionally dividing the nozzle into a first nozzle and a second nozzle, the first nozzle receiving the first exhaust gas stream from the first scroll, the second nozzle receiving the second exhaust gas stream from the second scroll;
• and
• a plurality of circumferentially spaced first vanes disposed in the first nozzle and a plurality of circumferentially spaced second vanes disposed in the second nozzle, the first and second vanes being rotatably mounted to the nozzle ring so as to be variable in setting angle for regulating exhaust gas flow to the turbine wheel.