Turbocharger system with reduced thrust load

Abstract

An exemplary compressor is provided. The compressor includes a plurality of blades, a hub defining a front surface and a back surface, and a first flow restriction structure provided at the back surface of the hub. The plurality of blades are arranged in a predefined manner on the front surface for receiving input air flow at a first pressure and compressing the input air flow to provide an output air flow at a second pressure higher than the first pressure. The first flow restriction member is configured for preventing at least a portion of the output air flow at the second pressure from entering into the back surface of the hub to reduce an air pressure at the back surface of the hub.

1 . A compressor comprising:
 a plurality of blades;   a hub defining a front surface and a back surface, the plurality of blades being arranged in a predefined manner on the front surface for receiving input air flow at a first pressure and compressing the input air flow to provide an output air flow at a second pressure higher than the first pressure; and   a first flow restriction member provided at the back surface of the hub, the first flow restriction member configured for preventing at least a portion of the output air flow at the second pressure from entering into the back surface of the hub to reduce an air pressure at the back surface of the hub.   
     
     
         2 . The compressor of  claim 1 , wherein the first flow restriction member is formed integral with the back surface of the hub. 
     
     
         3 . The compressor of  claim 1 , wherein the first flow restriction member is detachably coupled to the back surface of the hub. 
     
     
         4 . The compressor of  claim 1 , wherein the first flow restriction member extends from the back surface of the hub along a direction substantially parallel to a rotation axis that the hub rotates therewith, the first flow restriction member operates to deflect the air flow entering into the back surface of the hub and create a pressure difference at two sides of the first flow restriction member. 
     
     
         5 . The compressor of  claim 1 , wherein the first flow restriction member extends along a circumferential direction to form a ring-shaped member protruding backwardly from the back surface of the hub, the ring-shaped first flow restriction member divides the back surface into at least a first region and a second region, the first region is adjacent to the edge of the hub and the second region is adjacent to a rotational axis of the hub, wherein the first region has an air pressure higher than that of the second region during rotational movement of the hub. 
     
     
         6 . The compressor of  claim 1 , wherein the first flow restriction member comprises:
 a first surface extending substantially perpendicular to the back surface of the hub, the first surface deflecting at least a portion of the output air flow at the second pressure that enters into the back surface from a first direction to a second direction; and   a second surface connecting to the first surface, the second surface extending substantially parallel to the back surface, the second surface further deflecting the air flow from the second direction back to the first direction.   
     
     
         7 . The compressor of  claim 6 , wherein the first restriction member further comprises a third surface connecting to the second surface and the back surface, the third surface extending substantially perpendicular to the back surface, the third surface further deflecting the air flow from the first direction to a third direction which is opposite to the second direction. 
     
     
         8 . The compressor of  claim 6 , wherein the compressor is capable of being enclosed in a housing which comprises a first wall running substantially parallel to the first surface of the first flow restriction member, the first wall and the first surface defines a flow channel which has a first dimension when the first flow restriction member is stationary with respect to the hub and a second dimension when the first restriction member is rotating with the hub, wherein the second dimension is smaller than the first dimension due to a centrifugal force applied at the first flow restriction member when the hub is rotating. 
     
     
         9 . The compressor of  claim 1 , wherein the back surface of the hub is further provided with a second flow restriction member constructed substantially similar to the first flow restriction member, the first and second restriction members are spaced apart along a radial direction of the compressor. 
     
     
         10 . A turbocharger system for an internal combustion engine, the turbocharger system comprising:
 a turbine in flow communication with an exhaust manifold of the internal combustion engine for receiving exhaust gas discharged from the exhaust manifold and being driven to rotate by the exhaust gas;   a compressor coupled to the turbine through a drive shaft, the compressor driven to rotate by the drive shaft in response to a rotation of the turbine for supplying pressurized air to an intake of the internal combustion engine; and   a thrust bearing attached to the drive shaft for supporting at least a thrust load applied along an axial direction of the drive shaft;   wherein the compressor comprises a hub defining a back surface provided with a flow restriction member, the flow restriction member deflects a flow path of at least a portion of the pressurized air entering into the back surface at least once to create a pressure difference between two areas at least partially defined by the flow restriction member, and the pressure difference created by the flow restriction member causes the thrust load applied along the axial direction of the drive shaft to be reduced.   
     
     
         11 . The turbocharger system of  claim 10 , wherein the compressor is at least partially enclosed within a compressor housing, the flow restriction member is capable of being moved along a radial direction of the hub in response to a rotational movement of the hub and the dimension of a flow channel defined between the flow restriction member and a wall of the compressor housing is reduced due to the radial movement of the flow restriction member to reduce the amount of the pressurized air entering to the back surface of the hub. 
     
     
         12 . The compressor of  claim 10 , wherein the flow restriction member extends from the back surface along a direction substantially parallel to a rotation axis that the hub rotates therewith, the flow restriction member operates to deflect the pressurized air entering into the back surface of the hub and create a pressure difference at two sides of the flow restriction member. 
     
     
         13 . The compressor of  claim 10 , wherein the flow restriction member extends along a circumferential direction to form a ring-shaped member protruding backwardly from the back surface of the hub, the ring-shaped flow restriction member divides the back surface into at least a first region and a second region, the first region is adjacent to the edge of the hub and the second region is adjacent to the drive shaft, wherein the first region has an air pressure higher than that of the second region during rotational movement of the hub. 
     
     
         14 . A multi-stage turbocharger system for an internal combustion engine, the multi-stage turbocharger comprising:
 a low-pressure stage comprising:
 a low-pressure turbine; and 
 a low-pressure compressor capable of being driven by the low-pressure turbine to compress input air flow at a first air pressure and provide intermediate air flow at a second air pressure higher than the first air pressure; and 
   a high-pressure stage comprising:
 a high-pressure turbine; and 
 a high-pressure compressor placed downstream of the low-pressure compressor, the high-pressure compressor capable of being driven by the high-pressure turbine to compress at least a portion of the intermediate air flow provided from the low-pressure compressor and supply output air flow at a third air pressure higher than the second air pressure to an intake of the internal combustion engine; 
 wherein the high-pressure compressor is in flow communication with the low-pressure turbine. 
   
     
     
         15 . The multi-stage turbocharger system of  claim 14 , wherein the low-pressure stage further comprises:
 a low-pressure drive shaft for coupling the low-pressure turbine to the low-pressure compressor; and   a low-pressure thrust bearing attached to the low-pressure drive shaft for supporting at least a thrust load applied along an axial direction of the low-pressure drive shaft;   wherein at least a portion of the output air flow provided from the high-pressure compressor is diverted to a back surface of the low-pressure turbine to increase the air pressure at the back surface of the low-pressure turbine and reduce the thrust load applied along the axial direction of the low-pressure drive shaft.   
     
     
         16 . The multi-stage turbocharger system of  claim 14 , wherein the low-pressure compressor comprises a flow restriction member provided at a back surface of the low-pressure compressor, the flow restriction member deflects a flow path of at least a portion of the intermediate air flow entering into the back surface of the low-pressure compressor at least once to create a pressure difference between two areas at least partially defined by the flow restriction member, and the pressure difference created by the flow restriction member causes the thrust load applied along the axial direction of the low-pressure drive shaft to be reduced. 
     
     
         17 . The multi-stage turbocharger system of  claim 16 , wherein the flow restriction member extends along a circumferential direction to form a ring-shaped member protruding backwardly from the back surface of the low-pressure compressor, the ring-shaped flow restriction member divides the back surface of the low-pressure compressor into at least a first region and a second region, the first region is adjacent to the edge of the low-pressure compressor and the second region is adjacent to the low-pressure drive shaft, wherein the first region has an air pressure higher than that of the second region during rotational movement of the low-pressure compressor. 
     
     
         18 . The multi-stage turbocharger system of  claim 16 , wherein the flow restriction member is capable of being moved along a radial direction of the low-pressure compressor in response to a rotational movement of the low-pressure compressor and the dimension of a flow channel defined between the flow restriction member and a wall of a compressor housing is reduced due to the radial movement of the flow restriction member to reduce the amount of the intermediate air flow entering to the back surface of the low-pressure compressor. 
     
     
         19 . The multi-stage turbocharger system of  claim 14 , wherein the low-pressure compressor comprises a first flow restriction member and a second flow restriction member provided at a back surface of the low-pressure compressor, the first and second restriction members are spaced apart along a radial direction of the back surface of the low-pressure compressor, and the first and second restriction members operate to deflect a flow path of at least a portion of the intermediate air flow entering into the back surface of the low-pressure compressor at least once to create a pressure difference between areas at least partially defined by the first and second flow restriction members, and the pressure difference created by the flow restriction member causes the thrust load applied along the axial direction of the low-pressure drive shaft to be reduced. 
     
     
         20 . The multi-stage turbocharger system of  claim 18 , wherein the first and second flow restriction members extend along a circumferential direction to form ring-shaped members protruding backwardly from the back surface of the low-pressure compressor, the ring-shaped flow restriction members divide the back surface of the low-pressure compressor into at least a first region, a second region, and a third region, wherein the air pressure of the second region is smaller than that of the first region and greater than that of the third region.