Turbocharger with mixed flow turbine stage

Abstract

A turbocharger is disclosed for use with an engine. The turbocharger may include a housing at least partially defining a compressor shroud and a turbine shroud. The turbocharger may also include a compressor wheel disposed within the compressor shroud, a shaft connected to the compressor wheel, and a turbine wheel disposed within the turbine shroud and connected to an end of the shaft opposite the compressor wheel. The turbine wheel may have a generally annular hub, and a plurality of blades disposed radially around the hub. Each of the plurality of blades may include an airfoil having a hub face connected to the hub, a shroud face opposite the hub face and oriented towards the turbine shroud, a trailing edge, and a leading edge opposite the trailing edge. The leading edge may be substantially straight or substantially concave in a meridional plane. An angle between a base of the hub and the leading edge may be about 25-55 degrees. The turbocharger may also include a nozzle ring having a ring-shaped generally flat plate located at a periphery of the turbine wheel, and a plurality of vanes disposed radially around an upper surface of the plate. A camber of each of the plurality of vanes may be generally S-shaped along its meridional length from a leading edge to a trailing edge of each of the plurality of vanes.

What is claimed is: 
     
         1 . A turbine blade for a turbocharger, comprising:
 an airfoil having:
 a hub face connected to a turbine wheel hub of the turbocharger; 
 a shroud face located opposite the hub face and oriented towards a turbine shroud of the turbocharger; 
 a trailing edge; and 
 a leading edge opposite the trailing edge, 
   wherein an angle between the turbine wheel hub and the leading edge is about 25-55 degrees.   
     
     
         2 . The turbine blade of  claim 1 , wherein a solidity ratio of the turbine blade ranges from about 0.8 to 1.2 between the hub face and the shroud face. 
     
     
         3 . The turbine blade of  claim 1 , wherein an angle between a radial axis in a meridional plane of the turbine blade and the leading edge in the meridional plane is about 50-70 degrees. 
     
     
         4 . The turbine blade of  claim 1 , wherein an angle between a radial axis in a meridional plane of the turbine blade and the trailing edge in the meridional plane is about 0-14 degrees. 
     
     
         5 . The turbine blade of  claim 1 , wherein a ratio between an inlet width of the leading edge in a meridional plane of the turbine blade and a meriodional distance between the leading edge and the trailing edge ranges from about 0.20 to 0.42 between the hub face and the shroud face. 
     
     
         6 . The turbine blade of  claim 1 , wherein a ratio between a Z-axis offset in a meridional plane of the turbine blade and a meriodional distance between the leading edge and the trailing edge ranges from about 0.07 to 0.20 between the hub face and the shroud face. 
     
     
         7 . The turbine blade of  claim 1 , wherein the turbine blade has a blade angle that changes along its meridional length from about −80° to 30°. 
     
     
         8 . The turbine blade of  claim 7 , wherein the blade angle decreases from the hub face to the shroud face. 
     
     
         9 . The turbine blade of  claim 7 , wherein the blade angle is greatest for the turbine blade at the leading edge. 
     
     
         10 . The turbine blade of  claim 9 , wherein the blade angle ranges from about −5 to 30 degrees between the hub face and the shroud face at the leading edge. 
     
     
         11 . The turbine blade of  claim 7 , wherein the blade angle is lowest for the turbine blade at the trailing edge. 
     
     
         12 . The turbine blade of  claim 11 , wherein the blade angle ranges from about −40 to −80 degrees between the hub face and the shroud face at the trailing edge. 
     
     
         13 . The turbine blade of  claim 1 , wherein a thickness of the turbine blade varies along a meridional length of the turbine blade and decreases from the hub face to the shroud face. 
     
     
         14 . The turbine blade of  claim 13 , wherein the thickness is greatest at about 60-80% of the meridional length of the turbine blade. 
     
     
         15 . The turbine blade of  claim 14 , wherein a maximum thickness at the leading edge is about 0.38 times the greatest thickness along the meridional length. 
     
     
         16 . The turbine blade of  claim 14 , wherein a maximum thickness at the trailing edge is about 0.61 times the greatest thickness along the meridional length. 
     
     
         17 . The turbine blade of  claim 1 , wherein the leading edge is substantially straight. 
     
     
         18 . The turbine blade of  claim 1 , wherein the leading edge is substantially concave. 
     
     
         19 . A nozzle ring for a turbocharger, comprising:
 a ring-shaped generally flat plate having:
 an inner annular hub; and 
 an outer annular flange radially spaced apart from the inner annular hub; and 
   a plurality of vanes disposed between the inner annular hub and the outer annular flange,   wherein a camber of each of the plurality of vanes is generally S-shaped along its meridional length from a leading edge to a trailing edge of each of the plurality of vanes.   
     
     
         20 . The nozzle ring of  claim 19 , wherein the S-shaped camber generally inclines along its meridional length from the leading edge to the trailing edge. 
     
     
         21 . The nozzle ring of  claim 19 , wherein a vane angle of each of the plurality of vanes changes along its meridional length in a range from about 50 to 80 degrees. 
     
     
         22 . The nozzle ring of  claim 19 , wherein:
 each of the plurality of vanes includes a hub face and a shroud face; and   a vane angle along the hub face is substantially different from a vane angle along the shroud face.   
     
     
         23 . The nozzle ring of  claim 19 , wherein:
 each of the plurality of vanes includes a hub face and a shroud face; and   a vane angle along the hub face is substantially equal to a vane angle along the shroud face.   
     
     
         24 . The nozzle ring of  claim 19 , wherein a thickness of each of the plurality of vanes varies along its meridional length, the thickness being greatest at about 20-50% of the meridional length. 
     
     
         25 . The nozzle ring of  claim 24 , wherein a maximum thickness at the leading edge is about 0.25 times the greatest thickness along the meridional length. 
     
     
         26 . The nozzle ring of  claim 24 , wherein a maximum thickness at the trailing edge is about 0.09 times the greatest thickness along the meridional length. 
     
     
         27 . The nozzle ring of  claim 19 , wherein:
 each of the plurality of vanes includes a hub face and a shroud face; and   a solidity ratio of each of the plurality of vanes ranges from about 0.7 to 1.2 between the hub face and the shroud face.   
     
     
         28 . The nozzle ring of  claim 27 , wherein a ratio between a width of each of the plurality of vanes and a chord distance between the leading edge and the trailing edge ranges from about 0.20 to 0.40 between the hub face and the shroud face. 
     
     
         29 . The nozzle ring of  claim 28 , wherein a ratio between a distance from a center of a hub associated with the turbocharger to the leading edge of each of the plurality of vanes at the shroud face, and a distance from the center of the hub to a leading edge of a blade associated with the turbocharger at the shroud face ranges from about 1.3 to 1.5 between the hub face and the shroud face. 
     
     
         30 . The nozzle ring of  claim 29 , wherein a ratio between a distance from the center of the hub to the trailing edge of each of the plurality of vanes at the shroud face, and the distance from the center of the hub to the leading edge of the blade at the shroud face ranges from about 1.05 to 1.3 between the hub face and the shroud face. 
     
     
         31 . The nozzle ring of  claim 30 , wherein an angle between a line drawn between the center of the hub to the leading edge of each of the plurality of vanes at the shroud face, and a line drawn between the leading edge and the trailing edge is about 60-80 degrees. 
     
     
         32 . A turbocharger, comprising:
 a housing at least partially defining a compressor shroud and a turbine shroud;   a compressor wheel disposed within the compressor shroud;   a shaft connected to the compressor wheel;   a turbine wheel disposed within the turbine shroud and connected to an end of the shall opposite the compressor wheel, the turbine wheel including:
 a generally annular hub; and 
 a plurality of blades disposed radially around the annular hub, each of the plurality of blades including an airfoil having a hub face connected to the annular hub, a shroud face opposite the hub face and oriented towards the turbine shroud, a trailing edge, and a leading edge opposite the trailing edge, wherein an angle between a base of the annular hub and the leading edge is about 25-55 degrees; and 
   a nozzle ring including:
 a ring-shaped generally flat plate located at a periphery of the turbine wheel; and 
 a plurality of vanes disposed radially around an upper surface of the plate, wherein a camber of each of the plurality of vanes is generally S-shaped along its meridional length from a leading edge to a trailing edge of each of the plurality of vanes.