Patent Publication Number: US-7908857-B2

Title: Engine having a turbocharger coupler

Description:
FIELD 
     The present disclosure relates to engine assemblies, and more specifically to turbo couplings for engine assemblies. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
     Engine assemblies may incorporate the use of turbochargers to compress the air flowing into the engine to provide a greater amount of air to each cylinder. In order to compress the air flow into the engine, the turbocharger uses exhaust flow from the engine to spin a turbine, which in turn spins an air pump (or compressor). Since the turbine is in communication with the exhaust gas, temperatures of the turbine can be very high. As a result, a large amount of heat may be transferred to components, such as an exhaust manifold, that are coupled to the turbine. 
     SUMMARY 
     A turbo assembly may include a coupling member, a heat shield, and a turbo mechanism. The coupling member may include first and second ends and an annular body extending between the first and second ends. The first end may fix the coupling member to an exhaust manifold of an engine and the annular body may define an exhaust gas channel that receives exhaust gas from the exhaust manifold. The annular body may include a coolant passage that receives a coolant fluid. The heat shield may extend axially within the exhaust gas channel and radially between the annular body and an exhaust gas flow within the exhaust gas channel to limit an amount of heat transferred from the exhaust gas to the annular body. The turbo mechanism may include a housing fixed to the second end of the coupling member and in communication with the exhaust gas channel to receive the exhaust gas therefrom. 
     An engine assembly may include an exhaust manifold, a coupling member, a heat shield, and a turbo mechanism. The exhaust manifold may include an outlet and the coupling member may include first and second ends and an annular body extending between the first and second ends. The first end may fix the coupling member to the outlet of the exhaust manifold. The annular body may define an exhaust gas channel that receives exhaust gas from the exhaust manifold. The annular body may include a coolant passage that receives a coolant fluid. The heat shield may extend axially within the exhaust gas channel and radially between the annular body and an exhaust gas flow within the exhaust gas channel to limit an amount of heat transferred from the exhaust gas to the annular body. The turbo mechanism may include a housing fixed to the second end of the coupling member and in communication with the exhaust gas channel to receive the exhaust gas therefrom. 
     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
         FIG. 1  is a schematic illustration of an engine assembly according to the present disclosure; 
         FIG. 2  is a schematic illustration of a turbo assembly shown in  FIG. 1 ; 
         FIG. 3  is an additional schematic illustration of a coupling assembly shown in  FIG. 2 ; and 
         FIG. 4  is a schematic illustration of an alternate turbo assembly according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
     Referring to  FIG. 1 , an exemplary engine assembly  10  is schematically illustrated. The engine assembly  10  may include an engine  12  in communication with an intake system  14 , an exhaust system  16 , and turbo assembly  18 . In the example shown, the engine  12  may include a cylinder head  20  having an integrated exhaust manifold  22 . The integrated exhaust manifold  22  may be part of a single casting that forms the cylinder head  20  and may direct exhaust gas from the engine  12  to the turbo assembly  18 . 
     The intake system  14  may include a first intake conduit  24  supplying air to the turbo assembly  18 , a second intake conduit  26  in communication with the turbo assembly  18  and an intake manifold  30  in communication with the second intake conduit  26  and receiving the compressed air from the turbo assembly  18 . The exhaust system  16  may be in communication with the turbo assembly  18  and may direct exhaust gas from the turbo assembly  18 . 
     The turbo assembly  18  may include a turbo mechanism  32  and a coupling assembly  34 . The turbo mechanism  32  may include a turbine  36  and a compressor  38  located within a turbo housing  39 . The turbine  36  may be in communication with and driven by the exhaust gas from the engine  12 . The compressor  38  may be in communication with the first intake conduit  24  and may be driven by the turbine  36 . Supply and return lines  40 ,  42  may place the coupling assembly  34  in communication with a coolant fluid from the engine  12 . Additional supply and return lines  44 ,  46  may place the turbo mechanism  32  in communication with a coolant fluid from the engine  12 . 
     With reference to  FIGS. 2 and 3 , the coupling assembly  34  may include a coupling member  48  and a heat shield  50 . The coupling member  48  may include an annular body  52  extending between first and second ends  54 ,  56 . The annular body  52  defines an exhaust gas channel  57  therethrough. The first end  54  may include a first radially outwardly extending flange  58  having a series of apertures  60  extending therethrough and the second end  56  may include a second radially extending flange  61  having a series of apertures  62  extending therethrough. The annular body  52  may include a coolant passage  64  in communication with the coolant supply and return lines  40 ,  42 . As seen in  FIG. 3 , the coolant passage  64  may form an annular passage (or loop) within the annular body  52 . The annular body  52  may have a coolant inlet  66  in communication with the coolant supply line  40  and an outlet  68  in communication with the coolant return line  42 . The coolant passage  64  may extend around an entire circumference of the coupling member  48 . More specifically, the coolant passage  64  may extend around an entire circumference of the annular body  52 . 
     The heat shield  50  is disposed in the exhaust gas channel  57  and may include a radially extending flanged portion  70  and an axially extending body portion  72 . The flanged portion  50  may be located axially between the coupling member  48  and the exhaust manifold  22  and may include apertures  74  aligned with the apertures  60  in the coupling member  48 . The apertures  60 ,  74  may receive fasteners  76  that engage the exhaust manifold  22  to fix the coupling assembly  34  to the engine  12 . The heat shield  50  may be formed from stainless steel and the flanged portion  70  may form a gasket between the exhaust manifold  22  and the coupling member  48 . 
     The body portion  72  of the heat shield  50  may extend axially from the flanged portion  70  into the coupling member  48  toward the turbo mechanism  32 . The body portion  72  may include a first end  78  that is generally fixed axially at the flanged portion  70  and a second end  80  generally opposite the first end  78  and generally free from axial restraint. The body portion  72  may include first and second portions  82 ,  84  along the axial extent thereof. 
     The first portion  82  may extend from the first end  78  and may be axially aligned with the coolant passage  64  in the coupling member  48 . The first portion  82  may have an outer surface  88  that is offset radially inwardly relative to an inner surface  90  of the coupling member  48 , forming an air gap radially between the heat shield  50  and the coupling member  48 . The air gap may be axially aligned with the coolant passage  64 . More specifically, the outer diameter (D 1 ) of the outer surface  88  of the heat shield  50  may be less than the inner diameter (D 2 ) of the coupling member  48 , forming an annular air gap therebetween. 
     The second portion  84  may be located proximate the second end  80  of the body portion  72  of the heat shield  50 . The second portion  84  may extend into the housing  39  of the turbo mechanism  32  and may abut an inner surface  94  of the housing  39  to radially secure the second end  80 . The housing  39  of the turbo mechanism  32  may be fixed to the second radially extending flange  61  of the coupling member  48  with fasteners  96 . Alternatively, the second portion  84  may be located within the coupling member  48  and may engage the inner surface  90 . In either situation, the second portion  84  may be located axially downstream of the coolant passage  64 . 
     During engine operation, the air gap provided between the heat shield  50  and the coupling member  48  may reduce the amount of heat transferred from the exhaust gas to the coupling member  48 . As such, the heat rejection to the coolant within the coolant passage  64  from the exhaust gas may be reduced. The second portion  84  of the heat shield  50  may support the second end  80  of the heat shield  50  to improve fatigue characteristics and to reduce vibration of the heat shield  50 . The freedom of the second end  80  from axial constraint may accommodate thermal growth of the heat shield  50 . 
     An alternate turbo assembly  118  is shown in  FIG. 4 . It is understood that the turbo assembly  118  may be generally similar to the turbo assembly  18  with the exception of the features discussed below. The turbo assembly  118  may include a housing  139  having a turbo mechanism portion  138 , a coupling portion  148  that is integrally formed therewith and a heat shield  152 . The coupling portion  148  may be generally similar to the coupling member  48 . Additional coolant passages  155 ,  157  may extend from the coolant passage  154  into the turbo housing  139  so that a single set of coolant lines (not shown), similar to the supply line  44  and the return line  46  in  FIG. 1  may be used to feed both the coolant passage  154  in the coupling portion  148  as well as coolant passages (not shown) in the turbo mechanism portion  138 .