Patent Publication Number: US-2012024511-A1

Title: Intercooler

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is based on Japanese Patent Application No. 2010-168478 filed on Jul. 27, 2010, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an intercooler. 
     2. Description of Related Art 
     JP-A-2006-90305 (US 2006/0042607 A1) describes an intercooler having a tube and an inner fin arranged in the tube. The inner fin has a wavy cross-section, and the wavy cross-section of the inner fin partitions inside of the tube into passages. The inner fin linearly extends in a flowing direction of intake air, so that the inner fin is called as a straight fin. 
     The inner fin is constructed by alternately connecting first walls and second walls. The first wall partitions the inside of the tube into the passages, and a face of the second wall is fixed to an inner face of the tube. Both of the first wall and the second wall are constructed by simple planes. 
     The straight fin has a comparatively small flow resistance when intake air flows through the passages, so that a pressure loss of the intercooler is low. However, a boundary layer of intake air flow is easily generated on each face of the first wall and the second wall. In this case, a heat radiating property of the intercooler may be lowered. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing and other problems, it is an object of the present invention to provide an intercooler. 
     According to a first example of the present invention, an intercooler includes a flat tube and an inner fin arranged inside of the flat tube. While intake air to be drawn into an engine passes through the flat tube, the intake air is cooled by external fluid. The flat tube has two major faces opposing with each other in a thickness direction. The inner fin has a wave-shaped cross-section constructed by alternately connecting first walls and second walls in a major direction approximately perpendicular to the thickness direction. The second wall is approximately parallel with the two major faces. The first wall connects two of the second walls in a connecting direction corresponding to the thickness direction. The first wall linearly extends in a flowing direction of the intake air that is approximately perpendicular to the connecting direction and the major direction. The first wall has a protrusion protruding in the major direction and the protrusion is located at a middle position in the connecting direction. The protrusion is defined to have an extending dimension (x) in the connecting direction, and a protruding dimension (y) protruding from a face of the first wall in the major direction. The first wall is defined to have a height dimension (Fh) in the connecting direction, and the second wall is defined to have a width dimension (Fw) in the major direction. A ratio of the extending dimension to the height dimension is defined as a length ratio (x/Fh), and a ratio of the protruding dimension to the width dimension is defined as a protrusion ratio (y/Fw). When the length ratio (x/Fh) is applied to a lateral axis of a two-axis coordinate, and when the protrusion ratio (y/Fw) is applied to a vertical axis of the two-axis coordinate, the length ratio (x/Fh) and the protrusion ratio (y/Fw) are set to have values in an area surrounded by the vertical axis and lines connecting a point (x/Fh, y/Fw=0, 0), a point (x/Fh, y/Fw=0.89, 0.05), a point (x/Fh, y/Fw=1.0, 0.1), a point (x/Fh, y/Fw=0.87, 0.15), a point (x/Fh, y/Fw=0.77, 0.2), a point (x/Fh, y/Fw=0.64, 0.25), and a point (x/Fh, y/Fw=0, 0.4) in this order. 
     Accordingly, heat radiating property of the intercooler can be raised. 
     According to a second example of the present invention, an intercooler includes a flat tube and an inner fin arranged inside of the flat tube. While intake air to be drawn into an engine passes through the flat tube, the intake air is cooled by external fluid. The flat tube has two major faces opposing with each other in a thickness direction. The inner fin has a wave-shaped cross-section constructed by alternately connecting first walls and second walls in a major direction approximately perpendicular to the thickness direction. The second wall is approximately parallel with the two major faces. The first wall connects two of the second walls in a connecting direction corresponding to the thickness direction. The first wall linearly extends in a flowing direction of the intake air that is approximately perpendicular to the connecting direction and the major direction. The second wall has a protrusion protruding from an inner face of the second wall inward in the connecting direction. 
     Accordingly, heat radiating property of the intercooler can be raised. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings: 
         FIG. 1  is a schematic front view illustrating an intercooler according to a first embodiment; 
         FIG. 2  is a schematic cross-sectional view taken along line II-II of  FIG. 1 ; 
         FIG. 3  is a perspective view illustrating a protrusion of an inner fin of the intercooler; 
         FIG. 4A  is a front view illustrating the protrusion, and  FIG. 4B  is a side view illustrating the protrusion; 
         FIG. 5  is a side view illustrating a height dimension of the intercooler and an extending dimension of the protrusion; 
         FIG. 6  is a front view illustrating a width dimension of the intercooler and a protruding dimension of the protrusion; 
         FIG. 7  is a graph illustrating a relationship between a length ratio and a density ratio of supercharged air; 
         FIG. 8  is a graph illustrating a relationship between the length ratio and a protrusion ratio; 
         FIG. 9A  is a simulation model illustrating a flowing velocity distribution of intake air in a tube of the intercooler, and  FIG. 9B  is a simulation model illustrating a flowing velocity distribution of intake air in a tube of an intercooler of a comparison example; 
         FIGS. 10A-10D  are views respectively illustrating modifications of the protrusion according to a second embodiment; 
         FIG. 11  is a schematic perspective view illustrating a protrusion of an inner fin of an intercooler according to a third embodiment; and 
         FIG. 12  is a front view illustrating an intercooler according to other embodiment. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     First Embodiment 
     A first embodiment will be described with reference to  FIGS. 1-9B . As shown in  FIG. 1 , an air-cooled type intercooler  100 A has a few number of tubes  111 , and the tubes  111  are comparatively long. 
     Intake air is compressed by a turbocharger (not shown), and the compressed air is drawn into an engine (not shown) of a vehicle. The intake air may be hereinafter referred as supercharged air. The intercooler  100 A is a heat exchanger to cool the intake air by exchanging heat with cool air corresponding to external fluid. The intercooler  100 A mainly has a core part  110  and a pair of header tanks  120 ,  130 . Each component of the intercooler  100 A is made of aluminum or aluminum alloy which is excellent in thermal conductivity. The intercooler  100 A is produced by brazing, welding or swaging its components. 
     The core part  110  is constructed by alternately layering the tubes  111  and outer fins  112 . An inner fin  114  is arranged in the tube  111 . A side plate  113  is arranged on the outer fin  112  located most outside. 
     Intake air passes through the tube  111 , and the tube  111  has a flat rectangular cross-section, as shown in  FIG. 2 . A cross-sectional area of the tube  111  is made large as much as possible within a limited space, so as to reduce a flow resistance of intake air. 
     The flat tube  111  has two major faces  111   a  and two minor faces  111   b . The major face  111   a  is approximately parallel with a major side of the flat cross-section, and the minor face  111   b  is approximately parallel with a minor side of the flat cross-section. An inner face of the tube  111  is defined as a tube inner face  111   c.  The major side of the flat cross-section is defined to extend in a major direction. 
     The outer fin  112  is produced to have a wave shape by processing a thin plate material. Plural louvers  112   a  are defined in a plane part of the outer fin  112  by cutting and bending. The outer fin  112  increases an area of radiating (exchanging) heat toward cool air. Further, turbulent effects are generated by the louvers  112   a  so as to promote the heat exchange with intake air. A dimension of the outer fin  112  in a flowing direction of cool air is set approximately equal with that of the tube  111 . 
     The side plate  113  is a strengthening member extending in a longitudinal direction of the tube  111 . The side plate  113  has an approximately U-shape cross-section, and is arranged on the outer fin  112  located most outside in a tube layering direction. Open side of the U-shape cross-section of the side plate  113  is located outside and opposite from the tube  111  and the outer fin  112 . 
     A mountain (top) part of the outer fin  112  having the wave shape is contact and connected with the major face  111   a  of the tube  111 . The outer fin  112  located most outside is contact and connected with the side plate  113 . 
     As shown in  FIG. 1 , the header tank  120 ,  130  is disposed at an end of the tube  111  in the tube longitudinal direction. The tank  120 ,  130  extends in the tube layering direction, and communicates with each of the tubes  111 . The header tank  120  has a header plate  121 , a tank part  122 , and an inlet pipe  123 . The header tank  130  has a header plate  131 , a tank part  132 , and an outlet pipe  133 . 
     The header plate  121 ,  131  has a burring around an outer periphery, and has a tube hole at a position corresponding to the tube  111 . The burring has plural swaging nails, and the tank part  122 ,  132  is mechanically connected to the burring by swaging the nails. The end of the tube  111  is inserted and fitted with the tube hole. The tube  111  and the header plate  121 ,  131  are contact and connected with each other. An end of the side plate  113  in a longitudinal direction is contact and connected to the header plate  121 , and the other end of the side plate  113  is contact and connected to the header plate  131 . 
     The tank part  122 ,  132  is a semi-container open to the header plate  121 ,  131 . The open side of the tank part  122 ,  132  is located on an inner side of the burring of the header plate  121 ,  131 . A seal member (not shown) is interposed between the header plate  121 ,  131  and the tank part  122 ,  132 . The tank part  122 ,  132  is connected to the header plate  121 ,  131  by swaging the nails of the header plate  121 ,  131 . 
     The pipe  123 ,  133  is a communication portion that makes an inside of the tank part  122 ,  132  to communicate with outside. The pipe  123 ,  133  is integrated with the tank part  122 ,  132 . Intake air flows into the tank part  122  through the inlet pipe  123 , and is discharged out of the tank part  132  through the outlet pipe  133 . 
     The inner fin  114  is disposed inside the tube  111 . The inner fin  114  increases an area of exchanging heat with intake air flowing through the tube  111 , so as to promote heat exchange. The inner fin  114  is produced to have a waveform by processing a thin plate material. Because the tube  111  has the flat rectangular cross-section, the inner fin  114  is efficiently arranged in the tube  111  without creating a dead space. 
     As shown in  FIG. 2 , the inner fin  114  has a first wall  114   a  and a second wall  114   b.  The first wall  114   a  connects the second walls  114   b  in a connecting direction corresponding to an up-and-down direction of  FIG. 2 . The major faces  111   a  of the tube  111  oppose to each other in the connecting direction, and the first wall  114   a  extends in the connecting direction. The second wall  114   b  is approximately parallel with the major face  111   a  of the tube  111 , and extends in the major direction corresponding to a left-and-right direction of  FIG. 2 . 
     As shown in  FIG. 3 , an end of the second wall  114   b  is connected to the first wall  114   a,  and the other end of the second wall  114   b  is connected to another first wall  114   a.  The inner fin  114  has the waveform by alternately connecting the first walls  114   a  and the second walls  114   b  in the major direction. The first wall  114   a  extends approximately perpendicularly to the major face  111   a  in a manner that the connecting direction corresponds to a thickness direction of the flat tube  111 . In this case, the waveform of the inner fin  114  is rectangle or square. Alternatively, the connecting direction may be inclined with respect to the thickness direction. In this case, the waveform of the inner fin  114  is trapezoid. 
     The inner fin  114  is so-called straight type fin. The first wall  114   a  linearly extends in a flowing direction of intake air represented by a blank arrow direction in  FIGS. 3 and 4B . The first wall  114   a  is arranged in the tube  111  so as to connect the major faces  111   a  opposing with each other, so that an inside of the tube  111  is divided into plural passages. 
     The second wall  114   b  linearly extends in the flowing direction of intake air, similarly to the first wall face  114   a.  A face of the second wall  114   b  is contact and connected to the tube inner face  111   c.  A width dimension of the first wall  114   a  in the connecting direction is set longer than a width dimension of the second wall  114   b  in the major direction, and each passage is longer in the connecting direction than in the major direction. 
     As shown in  FIG. 3 , the first wall  114   a  has a protrusion  114   c,    114   d  at a middle position in the connecting direction. For example, the protrusion  114   c ,  114   d  is located at. a central position in the connecting direction. The protrusion  114   c  protrudes leftward in the major direction from the first wall  114   a  in  FIG. 3 , and the protrusion  114   d  protrudes rightward in the major direction from the first wall  114   a  in  FIG. 3 . Inside of the protrusion  114   c,    114   d  is recessed in the same direction. When the first wall  114   a  is seen from front, the protrusion  114   c,    114   d  extends in the connecting direction. Specifically, the protrusion  114   c,    114   d  has an ellipse shape, as shown in  FIG. 4B and 5 . 
     The protrusions  114   c  and the protrusions  114   d  are alternately arranged in the flowing direction of intake air, on the single first wall  114 . When the first walls  114   a  oppose to each other in the major direction, positions of the protrusions  114   c  correspond with each other in the major direction, and positions of the protrusions  114   d  correspond with each other in the major direction. 
     As shown in  FIG. 5 , the first wall  114   a  of the inner fin  114  is defined to have a height dimension Fh in the connecting direction, and the protrusion  114   c ,  114   d  is defined to have an extending dimension x in the connecting direction. As shown in  FIG. 6 , the second wall  114   b  is defined to have a width dimension Fw in the major direction, and the protrusion  114   c,    114   d  is defined to have a protruding dimension y protruding from the first wall  114   a  in the major direction. 
     A length ratio x/Fh is defined as a ratio of the extending dimension x to the height dimension Fh. A protrusion ratio y/Fw is defined as a ratio of the protruding dimension y to the width dimension Fw. The length ratio x/Fh and the protrusion ratio y/Fw are set to have values within a hatched area of  FIG. 8 . When the inner fin  114  is defined to have a fin pitch Fp between mountain parts of the wave shape located adjacent to each other, the width dimension Fw is equal to ½ of the fin pitch Fp. A temperature of intake air is raised when the intake air is compressed by a turbocharger (not shown), and the compressed air flows into the tank part  122  through the inlet pipe  123 . Intake air is distributed into the tubes  111  from the tank part  122 . While intake air flows inside of the tube  111 , intake air is cooled by external cool air through heat exchange. That is, heat of intake air is emitted to the external cool air through the inner fin  114 , the face  111   a,    111   b  of the tube  111 , and the outer fin  112 . The cooled air is gathered in the tank part  132 , and flows out of the outlet pipe  133  so as to be supplied to the engine. 
     The air-cooled type intercooler  100 A has a few number of the tubes  111 , and the tubes  111  are comparatively long. Therefore, if intake air of the intercooler  100 A is defined to have a pressure loss ΔPg represented by a following Expression 1, the pressure loss ΔPg becomes comparatively large. 
       ΔPg=4 ·f ·(H/de)·(ρ/2g)·Vg 2    (Expression 1)
 
     f=coefficient of friction 
     H=longitudinal length of the tube 
     de=diameter of a circle corresponding to the tube 
     p=density of the supercharged air 
     g=gravitational acceleration 
     Vg=flowing velocity of intake air in the tube 
     The straight type inner fin  114  is arranged in the tube  111  in a manner that the flow resistance of intake air becomes comparatively small.  FIG. 9A  illustrates a distribution of flowing velocity of intake air in the tube  111  of the first embodiment, and  FIG. 9B  shows a comparison example. The flowing velocity becomes slower in order of a flowing velocity FR 1 , a flowing velocity FR 2 , and a flowing velocity FR 3 , in  FIG. 9A . The flowing velocity becomes slower in order of a flowing velocity FR 11 , a flowing velocity FR 12 , a flowing velocity FR 13 , a flowing velocity FR 14 , and a flowing velocity FR  15 , in  FIG. 9B . 
     As shown in  FIG. 9B  representing the comparison example, a passage is defined by a wall not having the protrusion  114   c,    114   d,  and a boundary layer of intake air flow is easily generated on the second wall  114   b  and the tube inner face  111   c  corresponding to an opening part of the inner fin  114 . The boundary layer causes a decrease in the heat radiating property. 
     In contrast, according to the first embodiment, the flow resistance of intake air can be maintained low. Further, the protrusion  114   c,    114   d  is defined on the first wall  114   a  of the inner fin  114 , and the length ratio x/Fh and the protrusion ratio y/Fw are set to have values within the hatched area of  FIG. 8 . Therefore, as shown in  FIG. 4B , intake air flowing through the tube  111  can be deflected toward the second wall  114   b  and the tube inner face  111   c  opposite from with each other. The boundary layer formed on the second wall  114   b  and the tube inner face  111   c  can be disturbed, so that a thickness of the boundary layer can be reduced. Heat transmitting efficiency can be improved on the intake air side, and the heat radiating property can be raised. 
     As shown in  FIG. 9A  in contrast to  FIG. 9B , a distribution line of flowing velocity FR 1 , FR 2 , FR 3  is varied in a direction approaching the second wall  114   b  and the tube inner face  111   c.  It is confirmed that the thickness of the boundary layer is reduced. 
     A reason will be described below why the length ratio x/Fh and the protrusion ratio y/Fw are set to have the values within a predetermined range so as to obtain the above advantages. As shown in  FIG. 7 , an optimal condition to improve a density ratio (ρ/ρ0) of supercharged air is acquired when the length ratio x/Fh is variously changed between 0-1, using the protrusion ratio y/Fw as a. parameter. 
     The density ratio (ρ/ρ0) of supercharged air is a ratio of a density (ρ) of supercharged air of the first embodiment to a density (ρ0) of supercharged air of the comparison example. The density (ρ) of supercharged air indicates a density of air flowing out of the intercooler  100 A, and is represented by a heat radiation performance and a pressure loss of the intercooler  100 A. The density (ρ) of supercharged air is computed by the following Expression 2. 
       ρ=(Pg1-ΔPg)/{ R ·(Tg1-Qg/Gg·Cp)}  (Expression 2)
 
     Pg1=inlet-side pressure of intake air 
     ΔPg=pressure loss of intake air of the intercooler 
     R=gas constant 
     Tg1=inlet-side temperature of intake air 
     Qg=heat radiating amount 
     Gg=Mass flow rate of intake air 
     Cp=Specific heat of intake air 
     As the density (ρ) of supercharged air is raised, the pressure loss is reduced and the heat radiation property is made better, in the intercooler  100 A. Further, if the density ratio (ρ/ρ0) of supercharged air becomes equal to or higher than 100%, the properties of the intercooler  100 A are better than those of an intercooler of the comparison example. 
     In  FIG. 7 , when the length ratio x/Fh is increased from 0 to 1.0 with a parameter of the protrusion ratio y/Fw, the density ratio ρ/ρ0 of supercharged air becomes equal to or higher than 100%, and has a maximum value. 
     Specifically, the density ratio of ρ/ρ0 of supercharged air becomes equal to or higher than 100% and has the maximum value when the protrusion ratio y/Fw has a value of 0.05 and the length ratio x/Fh is in a range of 0-0.89. 
     The density ratio ρ/ρ0 of supercharged air becomes equal to or higher than 100% and has the maximum value when the protrusion ratio y/Fw has a value of 0.1 and when the length ratio x/Fh is in a range of 0-1.0. 
     The density ratio ρ/ρ0 of supercharged air becomes equal to or higher than 100% and has the maximum value when the protrusion ratio y/Fw has a value of 0.15 and when the length ratio x/Fh is in a range of 0-0.87. 
     The density ratio ρ/ρ0 of supercharged air becomes equal to or higher than 100% and has the maximum value when the protrusion ratio y/Fw has a value of 0.2 and when the length ratio x/Fh is in a range of 0-0.77. 
     The density ratio ρ/ρ0 of supercharged air becomes equal to or higher than 100% and has the maximum value when the protrusion ratio y/Fw has a value of 0.25 and when the length ratio x/Fh is in a range of 0-0.64. 
     That is, with respect to each protrusion ratio y/Fw, if the length ratio x/Fh is set in the above-mentioned predetermined range, the density p of supercharged air can be raised compared with the comparison example. The pressure loss is reduced, and the heat radiation property of the intercooler  100 A can be raised. 
     As shown in  FIG. 8 , when the length ratio x/Fh is applied to a lateral axis of a two-axis coordinate, and when the protrusion ratio y/Fw is applied to a vertical axis of the two-axis coordinate, the length ratio x/Fh and the protrusion ratio y/Fw are set to have values in an area surrounded by the vertical axis and lines connecting a point (x/Fh, y/Fw=0, 0), a point (x/Fh, y/Fw=0.89, 0.05), a point (x/Fh, y/Fw=1.0, 0.1), a point (x/Fh, y/Fw=0.87, 0.15), a point (x/Fh, y/Fw=0.77, 0.2), a point (x/Fh, y/Fw=0.64, 0.25), and a point (x/Fh, y/Fw=0, 0.4) in this order. In this case, the combination of the protrusion ratio y/Fw and the length ratio x/Fh causes the density ratio ρ/ρ0 of supercharged air to become more than or equal to 100%. The maximum side value of the length ratio x/Fh of  FIG. 7  to make the density ratio 100% or more is set as an upper limit of the length ratio x/Fh with respect to each point. 
     Especially, in  FIG. 7 , when the protrusion ratio y/Fw is set as 0.1, the density ratio ρ/ρ0 of supercharged air becomes the largest. At this time, the length ratio x/Fh may be preferably set in a range between 0.43 and 0.87. 
     The protrusion  114   c,    114   d  protruding on a first side in the major direction is produced by pressing the first wall  114   a  from a second side toward the first side. 
     Therefore, the protrusion  114   c,    114   d  can be easily formed by a roller processing or a pressing processing when the inner fin  114  is produced. 
     Second Embodiment 
     As shown in  FIGS. 10A-10D , an inner fin  114  has a protrusion  114   e,    114   f . Shape, number and location of the protrusion  114   e,    114   f  are different from those of the protrusion  114   c,    114   d  of the first embodiment. 
     As shown in  FIG. 10A , the protrusion  114   e  has a circle shape while the protrusion  114   c,    114   d  has the ellipse shape. The protrusion  114   e  may be formed by dimpling. As shown in  FIG. 10B , a plurality of the protrusions  114   e  may be arranged in the connecting direction. 
     As shown in  FIG. 10C , the protrusion  114   f  has a triangle shape while the protrusion  114   c,    114   d  has the ellipse shape. A first angle of the protrusion  114   f  having the triangle shape is located on an upstream side in the flowing direction of intake air A second angle and a third angle are located on a downstream side in the flowing direction of intake air, and arranged in the connecting direction. Intake air is effectively deflected toward the second wall  114   b  and the tube inner face  111   c  opposing with each other in the tube thickness direction. 
     As shown in  FIG. 10D , three of the circle protrusions  114   e  are arranged to define an imaginary triangle, and the protrusions  114   e  are respectively located at three angle portions of the imaginary triangle. Locations of the angle portions with respect to the flowing direction of intake air are the same as  FIG. 10C . 
     According to the second embodiment, similar advantages can be obtained as the first embodiment, if the length ratio x/Fh and the protrusion ratio y/Fw are set to have values within the hatched area of  FIG. 8 . In the case of  FIGS. 10B and 10D , the extending dimension x of the protrusions  114   e  is defined to be entire length of the protrusions  114   e  in the connecting direction. 
     Third Embodiment 
     As shown in  FIG. 11 , an inner fin  114  has a protrusion  114   g.  A location of the protrusion  114   g  is different from that of the protrusion  114   c,    114   d  of the first embodiment. 
     The protrusion  114   g  is defined in the second wall  114   b  by being pressed from outside to be connected to the tube inner face  111   c.  The protrusion  114   g  protrudes toward a center side of the tube  111 . That is, the protrusion  114   g  protrudes from an inner face of the second wall  114   b  toward an open side of the inner fin  114  having the waveform. For example, the protrusion  114   g  has a circle shape. 
     According to the third embodiment, the flow resistance of intake air can be maintained low. Further, the protrusion  114   g  is defined on the second wall  114   b  of the inner fin  114 , so that intake air flowing through the tube  111  adjacent to the second wall  114   b  can be disturbed by the protrusion  114   g.  The boundary layer formed on the second wall  114   b  can be disturbed, so that a thickness of the boundary layer can be reduced. Heat transmitting efficiency can be improved on the intake air side, and the heat radiating property can be raised. 
     Other Embodiment 
     The above embodiments may be applied to an intercooler  100 B shown in  FIG. 12 , which has a comparatively large number of tubes  111 , and the tubes  111  are comparatively short, compared with the intercooler  100 A. 
     The protrusion  114   c,    114   d,    114   e,    114   f,    114   g  is not limited to protrude on a first side in the major direction or the connecting direction by pressing the first wall  114   a  or the second wall  114   b  from a second side opposite from the first side in the major direction or the connecting direction. Alternatively, the protrusion  114   c ,  114   d,    114   e,    114   f,    114   g  may be formed by cutting and bending the wall  114   a,    114   b . In this case, the cut and separated part is located on a downstream side in the flowing direction of intake air, and the bent and connected part is located on an upstream side in the flowing direction of intake air. 
     Each component of the intercooler  100 A,  100 B is not limited to be made of aluminum or aluminum alloy, but may be made of copper-base material or iron base material. The header tank  120 ,  130  is not limited to be made of aluminum-base, copper-base or iron-base material, but may be made of resin material. 
     The intercooler  100 A,  100 B is not limited to the air-cooled type one using air as external fluid to cool the intake air, but may be a water-cooled type one using cooling water as the external fluid. 
     Such changes and modifications are to be understood as being within the scope of the present invention as defined by the appended claims.