Heat exchanger

Abstract

There is provided an evaporator ( 23 ) disposed between an exhaust manifold ( 22 ) and an exhaust pipe ( 24 ), the evaporator ( 23 ) including, in sequence from the upstream side toward the downstream side, a first exhaust gas passage ( 56 ) having a third stage heat exchanger (H 3 ), a second exhaust gas passage ( 55 ) having a second stage heat exchanger (H 2 ), and a third exhaust gas passage ( 50 ) having a first stage heat exchanger (H 1 ). Formed in the annular second exhaust gas passage ( 55 ) of the second stage heat exchanger (H 2 ) is a spiral passage divided by a spiral heat transfer plate ( 68 ), and arranged in a spiral shape so as to follow the heat transfer plate ( 68 ) are a plurality of undulating heat transfer tubes ( 67 ) that are stacked out of phase. Increasing the exhaust gas passage length by the heat transfer plate ( 68 ) and agitating the flow of exhaust gas by the heat transfer tubes ( 67 ) enables the opportunity for contact of the exhaust gas with the heat transfer plate ( 68 ) and the heat transfer tubes ( 67 ) to be increased, thereby enhancing the heat exchange efficiency.

1 . A heat exchanger that has a heat transfer member ( 61 ,  67 ,  68 ,  70 ) disposed so as to be in contact with a thermal fluid flowing within a thermal fluid passage ( 50 ,  55 ,  56 ) while the temperature of the thermal fluid decreases, and that recovers the thermal energy of the thermal fluid with a heat-absorbing medium via the heat transfer member ( 61 ,  67 ,  68 ,  70 ) by making the heat-absorbing medium flow within the heat transfer member ( 61 ,  67 ,  68 ,  70 ) in a direction opposite to the flow of the thermal fluid, 
 characterized in that the heat transfer member ( 67 ,  68 ) includes a guide member that deflects the flow of the thermal fluid, and a disturbing member that agitates the flow of the thermal fluid that has been deflected by the guide member.    
     
     
         2 . The heat exchanger according to  claim 1 , wherein the thermal fluid passage ( 50 ,  55 ,  56 ) is divided, from the upstream side toward the downstream side in the direction of flow of the thermal fluid, into a high temperature region, a medium temperature region, and a low temperature region, the temperature and the flow rate of the thermal fluid gradually decrease while flowing from the high temperature region to the low temperature region through the medium temperature region, and the guide member ( 68 ) and the disturbing member ( 67 ) are disposed at least in the medium temperature region.  
     
     
         3 . The heat exchanger according to  claim 2 , wherein the passage cross-sectional area of the thermal fluid passage ( 55 ) in the medium temperature region is constricted at an entrance ( 55   a ) thereof.  
     
     
         4 . The heat exchanger according to  claim 2 , wherein the thermal fluid passage ( 55 ) has an annular shape in the medium temperature region, the guide member ( 68 ) is formed from a spiral heat transfer plate disposed within the annular thermal fluid passage ( 55 ), and the disturbing member ( 67 ) is formed by winding a plurality of undulating heat transfer tubes in a spiral shape so as to follow the guide member ( 68 ), the plurality of undulating heat transfer tubes being stacked out of phase.  
     
     
         5 . The heat exchanger according to  claim 2 , wherein the flow of thermal fluid through the high temperature region is laminar.  
     
     
         6 . The heat exchanger according to  claim 2 , wherein the medium temperature region is arranged so as to cover the radially outer side of the high temperature region, and the low temperature region is arranged so as to cover the radially outer side of the medium temperature region.  
     
     
         7 . The heat exchanger according to  claim 1 , wherein the thermal fluid is exhaust gas of an internal combustion engine (E), and the heat exchanger is an evaporator ( 23 ) that evaporates the heat-absorbing medium with the heat of the exhaust gas.  
     
     
         8 . A heat exchanger that carries out heat exchange between a thermal fluid flowing through a thermal fluid passage ( 50 ,  55 ,  56 ) formed in the interior of a casing ( 31 ) and a heat-absorbing medium flowing within heat transfer members ( 61 ,  67 ,  70 ) disposed in the thermal fluid passage ( 50 ,  55 ,  56 ), 
 characterized in that the heat transfer member ( 61 ) positioned on the radially outermost side is fixed along an inner face of the casing ( 31 ).    
     
     
         9 . The heat exchanger according to  claim 8 , wherein the thermal fluid passage ( 50 ) formed along the inner face of the casing ( 31 ) is in a downstream section in the direction of flow of the thermal fluid.  
     
     
         10 . The heat exchanger according to  claim 8 , wherein the heat transfer member ( 61 ) secured along the inner face of the casing ( 31 ) is in an upstream section in the direction of flow of the heat-absorbing medium.  
     
     
         11 . The heat exchanger according to  claim 8 , wherein an outer face of the heat transfer member ( 61 ), which is wound in a spiral shape having substantially the same diameter as that of the casing ( 31 ), is fixed along the inner face of the casing ( 31 ), which is formed in a cylindrical shape.  
     
     
         12 . The heat exchanger according to  claim 8 , wherein the thermal fluid is exhaust gas of an internal combustion engine (E), and the heat exchanger is an evaporator ( 23 ) that evaporates the heat-absorbing medium with the heat of the exhaust gas.  
     
     
         13 . The heat exchanger according to  claim 3 , wherein the thermal fluid passage ( 55 ) has an annular shape in the medium temperature region, the guide member ( 68 ) is formed from a spiral heat transfer plate disposed within the annular thermal fluid passage ( 55 ), and the disturbing member ( 67 ) is formed by winding a plurality of undulating heat transfer tubes in a spiral shape so as to follow the guide member ( 68 ), the plurality of undulating heat transfer tubes being stacked out of phase.  
     
     
         14 . The heat exchanger according to  claim 3 , wherein the flow of thermal fluid through the high temperature region is laminar.  
     
     
         15 . The heat exchanger according to  claim 3 , wherein the medium temperature region is arranged so as to cover the radially outer side of the high temperature region, and the low temperature region is arranged so as to cover the radially outer side of the medium temperature region.  
     
     
         16 . The heat exchanger according to  claim 2 , wherein the thermal fluid is exhaust gas of an internal combustion engine (E), and the heat exchanger is an evaporator ( 23 ) that evaporates the heat-absorbing medium with the heat of the exhaust gas.  
     
     
         17 . The heat exchanger according to  claim 9 , wherein the heat transfer member ( 61 ) secured along the inner face of the casing ( 31 ) is in an upstream section in the direction of flow of the heat-absorbing medium.  
     
     
         18 . The heat exchanger according to  claim 9 , wherein an outer face of the heat transfer member ( 61 ), which is wound in a spiral shape having substantially the same diameter as that of the casing ( 31 ), is fixed along the inner face of the casing ( 31 ), which is formed in a cylindrical shape.  
     
     
         19 . The heat exchanger according to  claim 9 , wherein the thermal fluid is exhaust gas of an internal combustion engine (E), and the heat exchanger is an evaporator ( 23 ) that evaporates the heat-absorbing medium with the heat of the exhaust gas.  
     
     
         20 . The heat exchanger according to  claim 10 , wherein the thermal fluid is exhaust gas of an internal combustion engine (E), and the heat exchanger is an evaporator ( 23 ) that evaporates the heat-absorbing medium with the heat of the exhaust gas.