Patent ID: 8590305

Claim:
A turbocharger comprising: a turbine housing ( 2 ) including at least one volute ( 47 , 48 , 49 ), a turbine wheel ( 70 ) carried within the turbine housing and adapted to being driven by exhaust gas, a transition area ( 39 ) where exhaust from the volute(s) is transmitted to the turbine wheel, first and second cylinders ( 81 ) with end faces ( 58 , 59 ) with contours ( 85 , 86 ) defining said transition area, wherein said first contour ( 85 ) is part of said first cylinder end face ( 58 ), generally coaxial and concentric to the turbine wheel and movable parallel to the axis of rotation of the turbine wheel, and wherein said second contour ( 86 ) is part of a said second cylinder end face ( 59 ), generally coaxial and concentric to the turbine wheel and movable parallel to an axis of rotation of the turbine wheel; and drive means for simultaneously moving said first and second cylinder end faces towards each other.