Simplified variable geometry turbocharger with increased flow range

Abstract

A variable geometry turbocharger is simplified yet able to maintain pulse energy. In a first embodiment, a turbine housing is provided with a pivoting flow control valve which pivots about a point near the entry to the turbine housing. By moving the valve about the pivot point, the effective volume of the turbine housing volute is varied, thus effectively reducing the volume of exhaust gas in the volute, allowing control of exhaust gas flowing to the turbine wheel. In the second embodiment of the invention, a rotating wedge segment within the volute is rotated from a first position to a second position, changing the effective volume of the volute and allowing control of exhaust gas flowing to the turbine wheel.

I claim: 
     
         1 . A variable flow turbocharger comprising:
 (a) a turbine housing ( 2 ) having a turbine inlet portion at a turbine housing foot ( 51 ) for coupling to an exhaust manifold for receiving exhaust gas flow, a turbine exducer portion ( 52 ) and a volute chamber between the turbine housing foot and the exducer portion;   (b) a turbine impeller ( 70 ) having a multiplicity of blades located within said turbine housing for receiving exhaust gas flow from the volute chamber;   (c) at least one volute divider wall to divide the volute chamber into a larger volute chamber ( 48 ) and a smaller volute chamber ( 49 ); and   (d) exhaust flow control valve means adapted to control the degree of blockage of exhaust gases flowing into the larger volute chamber.   
     
     
         2 . The variable flow turbocharger according to  claim 1 , wherein said exhaust flow control valve means is variably adjustable. 
     
     
         3 . The variable flow turbocharger according to  claim 1 , wherein said volute divider wall includes openings through which exhaust flow can pass between the larger and smaller volute chambers. 
     
     
         4 . The variable flow turbocharger according to  claim 1 , wherein said divider wall is an axial divider wall. 
     
     
         5 . The variable flow turbocharger according to  claim 1 , wherein said divider wall is a radial divider wall. 
     
     
         6 . The variable flow turbocharger according to  claim 1 , wherein the volume of the larger volute comprises at least about 55% of the divided volute space and the volume of the smaller volute comprises at most about 45% of the divided volute space. 
     
     
         7 . The variable flow turbocharger according to  claim 1 , wherein the volume of the larger volute comprises about 55-65% and the volume of the smaller volute comprises about 45-35% of the divided volute. 
     
     
         8 . The variable flow turbocharger according to  claim 1 , comprising at least two axial or radial divider walls. 
     
     
         9 . The variable flow turbocharger according to  claim 1 , wherein the divider wall is radial, and wherein the smaller volute ( 49 ) is on the exducer side and the larger volute ( 48 ) is opposite the exducer side. 
     
     
         10 . The variable flow turbocharger according to  claim 1 , wherein exhaust flow control valve means comprises a pivotable valve member ( 72 ) adapted for pivoting between an open position wherein flow to the larger volute ( 48 ) is not restricted and a blocking position wherein flow to the larger volute ( 48 ) is effectively blocked. 
     
     
         11 . An internal combustion engine including an exhaust manifold and having a variable flow turbocharger fluidly coupled to the exhaust manifold, the variable-capacity turbocharger comprising:
 (a) a turbine housing ( 2 ) having a turbine inlet portion, a turbine exducer portion ( 52 ) and a volute chamber;   (b) a turbine impeller located in said turbine housing and having a multiplicity of blades;   (c) at least one volute divider wall extending to the vicinity of said turbine inlet portion to divide said volute chamber into a larger volute chamber ( 48 ) and a smaller volute chamber ( 49 );   (d) a divided exhaust manifold ( 36 ) including a first exhaust introducing passageway for introducing exhaust gases into said larger volute chamber and a second exhaust introducing passageway for introducing exhaust gases into said smaller volute chamber; and   (e) exhaust flow control valve means located at least in the first exhaust introducing passageway to control the degree of blockage of exhaust gases flowing into said first exhaust introducing passageway.   
     
     
         12 . The variable flow turbocharger according to  claim 11 , wherein said exhaust flow control valve means is located in the turbine housing. 
     
     
         13 . The variable flow turbocharger according to  claim 11 , wherein said exhaust flow control valve means is located in the exhaust manifold coupled to said turbine housing. 
     
     
         14 . The variable flow turbocharger according to  claim 11 , wherein said exhaust flow control valve means is located between the exhaust manifold and the turbine housing.