Variable geometry turbine

Abstract

A variable geometry turbine comprising: a housing; a turbine wheel supported within said housing for rotation about a turbine axis; an annular inlet passage within said housing upstream of said turbine wheel and defined between respective radial inlet surfaces of first and second wall members; an outlet passage within said housing downstream of said turbine wheel; an array of vanes extending across the inlet passage, said vanes being connected to said first wall member; at least one of said first and second wall members being moveable along the turbine axis to vary the size of the inlet passage and/or at least one of said vanes being rotationally moveable about an axis that is substantially parallel to said turbine axis to vary the size of the inlet passage; wherein at least one particulate filter is provided within said housing at a location such that said particulate filter can be contacted by particulate matter flowing through said turbine during use.

1 . A variable geometry turbine comprising:
 a housing;   a turbine wheel supported within said housing for rotation about a turbine axis;   an annular inlet passage within said housing upstream of said turbine wheel and defined between respective radial inlet surfaces of first and second wall members;   an outlet passage within said housing downstream of said turbine wheel;   an array of vanes extending across the inlet passage, said vanes being connected to said first wall member;   at least one of said first and second wall members being moveable along the turbine axis to vary the size of the inlet passage or at least one of said vanes being rotationally moveable about an axis that is substantially parallel to said turbine axis to vary the size of the inlet passage;   
       wherein at least one particulate filter is provided within said housing at a location such that said particulate filter can be contacted by particulate matter flowing through said turbine during use. 
     
     
         2 . A turbine according to  claim 1 , wherein said first wall member defines a further radial surface opposite to said radial inlet surface and said at least one particulate filter is connected to said further radial surface. 
     
     
         3 . A turbine according to  claim 2 , wherein said first wall member comprises at least one axially extending flange which extends away from said inlet passage and towards said housing, said at least one flange defining a space behind the first wall member in which said at least one particulate filter is provided. 
     
     
         4 . A turbine according to  claim 3 , wherein said at least one axially extending flange defines one or more radially extending apertures to define radial flow path for exhaust emissions to flow behind the radial inlet surface of the first wall member during use. 
     
     
         5 . A turbine according to  claim 4  wherein said at least one particulate filter radially overlies said one or more radially extending apertures such that said at least one particulate filter is disposed in said radial flow path. 
     
     
         6 . A turbine according to  claim 3 , wherein said at least one particulate filter is dimensioned to occupy at least around 10% of the volume of said space. 
     
     
         7 . A turbine according to  claim 3 , wherein at least one particulate filter is connected to at least one of said flange(s). 
     
     
         8 . A turbine according to  claim 1 , wherein said first wall member is moveable along the turbine axis to vary the size of the inlet passage and said first wall member defines at least one axially extending flange which extends into an axially extending cavity defined by the housing behind the radial inlet surface of the first wall member, at least one particulate filter being provided in said cavity. 
     
     
         9 . A turbine according to  claim 8 , wherein said at least one particulate filter is dimensioned to occupy at least around 10% of the volume available within said cavity remaining after receipt of said first wall member within said cavity. 
     
     
         10 . A turbine according to  claim 8 , wherein said cavity is defined by one or more surfaces of the housing and said at least one particulate filter is connected to at least one of said one or more surfaces. 
     
     
         11 . A turbine according to  claim 8 , wherein said at least one axially extending flange defines one or more radially extending apertures to define a radial flow path for exhaust emissions to flow behind the radial inlet surface of the first wall member during use. 
     
     
         12 . A turbine according to  claim 11 , wherein said at least one particulate filter defines one or more first openings arranged to radially overlie said one or more radially extending apertures such that said radial flow path extends through said first openings. 
     
     
         13 . A turbine according to  claim 12 , wherein said one or more first openings are in fluid communication with one or more first channels defined by the at least one particulate filter such that said radial flow path extends along said first channel(s). 
     
     
         14 . A turbine according to  claim 13 , wherein said one or more first channels extend through said at least one particulate filter such that said radial flow path extends through said at least one particulate filter. 
     
     
         15 . A turbine according to  claim 11 , wherein said at least one particulate filter radially overlies said one or more radially extending apertures such that said at least one particulate filter is disposed in said radial flow path. 
     
     
         16 . A turbine according to  claim 1 , wherein said radial inlet surface of said first wall member defines one or more axially extending apertures which define an axial flow path for gas to flow through the first wall member during use. 
     
     
         17 . A turbine according to  claim 16 , wherein said at least one particulate filter defines one or more second openings arranged to axially overlie said one or more axially extending apertures such that said axial flow path extends through said second openings. 
     
     
         18 . A turbine according to  claim 17 , wherein said one or more second openings are in fluid communication with one or more second channels defined by the at least one particulate filter such that said axial flow path extends along said channel(s). 
     
     
         19 . A turbine according to  claim 18 , wherein said one or more second channels extend through said at least one particulate filter such that said axial flow path extends through said at least one particulate filter. 
     
     
         20 . A turbine according to  claim 16 , wherein said at least one particulate filter is provided behind said one or more axially extending apertures such that said at least one particulate filter is disposed in said axial flow path. 
     
     
         21 . A turbine according to  claim 1 , wherein at least one particulate filter is connected to a section of the housing which is upstream of the inlet passage of the turbine. 
     
     
         22 . A turbine according to  claim 1 , wherein at least one particulate filter is connected to a section of the housing which at least partially defines the outlet passage of the turbine. 
     
     
         23 . A turbine according to  claim 1 , wherein said at least one particulate filter comprises a high surface area material. 
     
     
         24 . A turbine according to  claim 23 , wherein said high surface area material possesses a surface area that is sufficiently high to facilitate aerial oxidation of particulate matter deposited on said high surface area material. 
     
     
         25 . A turbine according to  claim 1 , wherein said at least one particulate filter comprises a catalytic material suitable to catalyse the conversion of particulate matter into one or more different species. 
     
     
         26 . A turbine according to  claim 1 , wherein said at least one particulate filter is configured to support captured particulate matter away from an adjacent surface of the housing. 
     
     
         27 . A turbine according to  claim 1 , wherein said at least one particulate filter is configured to support captured particulate matter in or adjacent to further particulate matter flowing through the turbine during use. 
     
     
         28 . A nozzle ring for a variable geometry turbine, said nozzle ring comprising:
 a radial wall defining a first radial surface and a second opposite radial surface, an array of vanes extending from said first radial surface;   radially inner and outer axially extending flanges which, together with the second radial surface, define an annular space behind the first radial surface;   wherein at least one particulate filter is provided in said annular space.   
     
     
         29 . A nozzle ring according to  claim 28 , wherein said at least one particulate filter is connected to said second radial surface, said radially inner axially extending flange and/or said radially outer axially extending flange. 
     
     
         30 . A nozzle ring according to  claim 28 , wherein each of said axially extending flanges defines one or more radially extending apertures configured such that, in use, said radially extending apertures define a radial flow path for exhaust emissions to flow behind the first radial surface. 
     
     
         31 . A nozzle ring according to  claim 28 , wherein said radial wall defines one or more axially extending apertures configured such that, in use, said axially extending apertures define an axial flow path for gas to flow through the radial wall. 
     
     
         32 . A variable geometry turbine comprising a nozzle ring according to  claim 28 . 
     
     
         33 . A turbocharger comprising a variable geometry turbine according to  claim 1 .