Patent ID: 7249930
Filing Date: 2007-07-31
Classification: F01D,F02B,F05D

Abstract:
1. A turbine housing assembly for a turbocharger having a variable-nozzle turbine, comprising: a turbine housing defining a bore extending therethrough in an axial direction, the turbine housing defining a chamber surrounding the bore for receiving exhaust gas to be directed into the bore, the turbine housing further defining a nozzle leading from the chamber into the bore; a tubular piston disposed in the bore of the turbine housing and axially slidable relative to the turbine housing, the piston being slidable between a closed position and an open position for blocking the nozzle by an amount dependent on axial positioning of the piston so as to regulate flow into the bore; a bypass passage defined in the turbine housing for allowing a portion of exhaust gas to flow from the chamber through the bypass passage without passing through the turbine housing bore; and a bypass control member disposed in the turbine housing and slidable between a no-bypass position closing the bypass passage and a bypass position opening the bypass passage, wherein the piston and bypass control member are structured and arranged such that the piston slides while the bypass control member remains stationary for a part of a full stroke of the piston from the closed position toward the open position thereof, and then the piston engages the bypass control member and causes the bypass control member to slide together with the piston as the piston further slides toward the open position thereof such that the bypass control member is moved toward the bypass position.