Turbocharger with turbine nozzle vanes and an annular rotary bypass valve

A turbocharger comprising:

• a compressor wheel mounted within a compressor housing;
• a turbine housing defining at least part of a generally annular chamber extending circumferentially about a longitudinal axis of the turbine housing, the turbine housing defining a bore extending along the longitudinal axis;
• a turbine wheel disposed in the turbine housing;
• a nozzle passage leading from the chamber radially inwardly into the turbine wheel;
• a variable vane assembly having vanes disposed in the nozzle passage for guiding exhaust gas flowing toward the turbine wheel;
• the turbine housing defining an annular bypass passage surrounding the bore and arranged to allow exhaust gas in the chamber to bypass the turbine wheel;
• and
• an annular bypass valve disposed in the bypass passage, the bypass valve comprising a fixed annular valve seat and a rotary annular valve member, the valve member being disposed against the valve seat and being rotatable about the longitudinal axis for selectively varying a degree of alignment between respective orifices defined through each of the valve seat and valve member, ranging from no alignment defining a closed condition of the bypass valve, to at least partial alignment defining an open condition of the bypass valve;
• wherein the variable vane assembly comprises fixed vanes disposed in the nozzle passage, and a rotor that is rotational with respect to the turbine housing about the longitudinal axis, wherein the rotor defines a plurality of circumferentially spaced movable vanes each of which overlaps in a circumferential direction with a respective one of the fixed vanes to form a composite vane having a leading-edge portion defined by the movable vane and a trailing-edge portion defined by the fixed vane, the rotor being rotatable for varying a degree of overlap between the fixed vanes and the movable vanes;
• and
• wherein the rotor is mechanically coupled with the rotary valve member of the bypass valve such that the rotor and valve member rotate together.