JP2007085266A - Heat exchange apparatus of exhaust system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a heat exchange apparatus of an exhaust system which can efficiently exchange heat between exhaust gas and a heat medium. <P>SOLUTION: An exhaust heat recovery section 36 applied to the exhaust system 10 for a vehicle has a construction such that a cooling water pipe 38 is installed in a downstream-side conical portion 34 of a catalyst case 28 through which the exhaust gas flows. The cooling water pipe 38 includes a spiral heat exchange section 38A, as viewed in the axial direction, so that the curvature of the heat exchange section continuously varies from the upstream side to the downstream side in the direction of a flow of the exhaust gas. The heat exchange section 38A is coaxially disposed within the downstream-side conical portion 34. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an exhaust heat exchanger for recovering exhaust heat of exhaust gas of an internal combustion engine, for example.

A configuration in which a spiral water passage pipe is disposed in an exhaust pipe of an internal combustion engine is known (for example, see Patent Document 1).
JP-A-2-136507 Japanese Patent Laid-Open No. 7-259548 JP 2002-115802 A

  However, in the conventional technology as described above, since the water pipe is disposed at the axial center portion of the exhaust pipe, only the exhaust heat of the exhaust gas passing through the axial center portion of the exhaust pipe can be recovered.

  In view of the above fact, an object of the present invention is to obtain an exhaust system heat exchange device capable of efficiently performing heat exchange between exhaust and a heat medium.

  In order to achieve the above object, an exhaust system heat exchanging device according to the first aspect of the present invention is an exhaust system in which a heat medium pipe is arranged in the exhaust system and heat exchange between the heat medium flowing through the heat medium pipe and the exhaust gas is performed. In the heat exchanger system, the heat medium pipe has a heat exchange part formed in a spiral shape in an axial view so that the curvature continuously changes from the upstream side to the downstream side in the exhaust flow direction. It arrange | positions coaxially in the exhaust flow path which comprises the said exhaust system.

  In the exhaust heat exchanger according to claim 1, heat exchange between the exhaust flowing through the exhaust flow path and the heat medium flowing through the heat exchange section of the heat medium pipe is performed in the exhaust flow path where the heat medium pipe is disposed. Is called.

  Here, since the heat exchange part of the heat medium pipe is formed in a spiral shape when viewed in the axial direction, the heat medium channel faces the upstream side in the exhaust flow direction in a wide area in the exhaust channel, and efficiently exchanges heat. Is done. In addition, the heat exchange part of the heat medium pipe has one end side in the heat medium flow direction located upstream in the exhaust flow direction and the other end side located in the downstream side.In other words, the heat medium pipe has a tapered spiral shape. Therefore, an increase in back pressure (exhaust resistance) is suppressed as compared with a configuration in which the heat medium pipe is simply formed in a spiral shape along the cross section perpendicular to the axis of the exhaust flow path.

  Thus, in the exhaust heat exchanger according to claim 1, heat exchange between the exhaust and the heat medium can be performed efficiently.

  An exhaust system heat exchanging device according to a second aspect of the present invention is an exhaust system heat exchanging device in which a heat medium pipe is arranged in the exhaust system and heat exchange is performed between the heat medium flowing through the heat medium pipe and the exhaust gas. The exhaust system includes a rectification unit that rectifies the exhaust flow, and a heat exchange passage that is continuous downstream of the rectification unit in the exhaust flow direction, and the heat medium pipe extends from the upstream side in the exhaust flow direction. A heat exchange section formed in a spiral shape in an axial view so that the curvature continuously changes toward the downstream side is coaxially disposed in the heat exchange flow path.

  In the exhaust system heat exchange device according to claim 2, the exhaust gas rectified by passing through the rectification unit and introduced into the heat exchange channel flows through the heat exchange unit disposed in the heat exchange channel in the heat medium pipe. Heat exchange with the heat medium is performed.

  Here, since the heat exchange part of the heat medium pipe is formed in a spiral shape when viewed in the axial direction, the heat medium channel faces the upstream side in the exhaust flow direction in a wide area in the heat exchange channel, and heat is efficiently generated. Exchange is performed. In particular, the exhaust gas is rectified by passing through the rectification unit, and the flow in the heat exchange flow path (cross section) is made uniform, so that heat exchange between the exhaust gas and the heat medium can be performed more efficiently.

  Thus, in the exhaust system heat exchange device according to the second aspect, heat exchange between the exhaust and the heat medium can be performed efficiently. In addition, the heat exchange part of the heat medium pipe has one end side in the heat medium flow direction located upstream in the exhaust flow direction and the other end side located in the downstream side.In other words, the heat medium pipe has a tapered spiral shape. Therefore, an increase in back pressure (exhaust resistance) is suppressed as compared with a configuration in which the heat medium pipe is simply formed in a spiral shape along the cross section perpendicular to the axis of the exhaust flow path.

  An exhaust heat exchanger according to a third aspect of the present invention is the exhaust heat exchanger according to the second aspect, wherein the rectifying unit is a catalyst in which a large number of linear narrow channels along the exhaust flow direction are arranged in parallel. .

  In the exhaust system heat exchange device according to the third aspect, the exhaust gas is rectified by passing through a large number of narrow flow paths of the catalyst (supporting body supporting the catalyst). By disposing the heat exchange part of the heat medium pipe downstream of the catalyst part, good heat exchange efficiency can be obtained without relying on a dedicated rectifying part.

  In order to achieve the above object, an exhaust system heat exchanging device according to a fourth aspect of the present invention is an exhaust system that arranges a heat medium pipe in the exhaust system and performs heat exchange between the heat medium flowing in the heat medium pipe and the exhaust gas. The exhaust system has a catalyst case that contains a catalyst in which a large number of linear narrow channels along the exhaust flow direction are arranged in parallel, and the catalyst case contains a catalyst part that contains the catalyst And a taper portion formed in a taper shape continuous to the downstream side in the exhaust flow direction of the catalyst portion, and the heat medium pipe has a curvature continuously from the upstream side to the downstream side in the exhaust flow direction. A heat exchanging portion formed in a spiral shape having a spiral shape as viewed in the axial direction so as to change is arranged coaxially and in a taper direction within the taper portion of the catalyst case.

  In the exhaust system heat exchange device according to claim 4, the exhaust gas rectified by passing through a number of narrow channels of the catalyst in the catalyst case (the carrier carrying the catalyst) and discharged to the taper portion of the catalyst case; Heat exchange with the heat medium flowing through the heat exchange part arranged in the tapered part in the heat medium pipe is performed.

  Here, since the heat exchange part of the heat medium pipe is formed in a spiral shape when viewed in the axial direction, the heat medium channel faces the upstream side in the exhaust flow direction in a wide area in the exhaust channel, and efficiently exchanges heat. Is done. In particular, exhaust gas passes through the catalyst and is rectified, and the exhaust flow is made uniform at each radial portion of the tapered portion, so that heat exchange between the exhaust gas and the heat medium becomes more efficient.

  Thus, in the exhaust system heat exchange device according to the fourth aspect, heat exchange between the exhaust and the heat medium can be performed efficiently. In addition, since the heat medium pipe has a taper spiral shape in the heat exchange part of the heat medium pipe, the heat medium pipe is simply formed in a spiral shape along the cross section perpendicular to the axis of the exhaust flow path, or the taper part is the most. Compared with the configuration formed in a spiral shape along the cylindrical surface corresponding to the small diameter portion, an increase in back pressure (exhaust resistance) is suppressed.

  An exhaust system heat exchange device according to a fifth aspect of the present invention is the exhaust system heat exchange device according to the fourth aspect, wherein the heat exchange portion of the heat medium pipe has a taper angle of a taper portion inner peripheral surface of the catalyst case. It matches the corner.

  6. The exhaust heat exchanger according to claim 5, wherein the taper angle (cone angle) of the heat exchange part of the heat medium pipe substantially coincides with the taper angle of the taper part of the catalyst case. Exhaust flows substantially uniformly inside and outside the heat exchange part of the pipe, and the heat exchange efficiency is further improved.

  The exhaust heat exchanger according to claim 6 is the exhaust heat exchanger according to any one of claims 1 to 5, wherein the heat exchange portion of the heat medium pipe is the same in the circumferential direction. At the position, the inner diameter of the large diameter side portion is larger than the outer diameter of the small diameter side portion.

  In the exhaust system heat exchange device according to the sixth aspect, the heat exchange part of the heat medium pipe has a spiral shape in which the upstream part and the downstream part do not overlap each other when viewed from the axial direction. For this reason, each part of a heat exchange part does not become a shadow with respect to an exhaust flow, but exhaust_gas | exhaustion contacts a heat exchange part substantially uniformly. Thereby, heat exchange efficiency improves further.

  The exhaust heat exchanger according to claim 7 is the exhaust heat exchanger according to any one of claims 1 to 6, wherein the heat exchange part of the heat medium pipe has a larger curvature side. The heat medium is introduced from.

  In the exhaust system heat exchange device according to the seventh aspect, the heat medium is introduced into the shaft center portion having a high exhaust temperature in the exhaust passage (heat exchange passage, taper portion of the catalyst case). Since the exhaust performs heat exchange with a low-temperature heat medium, the temperature of the heat medium can be increased or the temperature of the exhaust can be increased quickly. Further, the temperature distribution in each part in the radial direction of the exhaust flow path is made more uniform.

  The exhaust heat exchanger according to claim 8 is the exhaust heat exchanger according to any one of claims 1 to 7, wherein the heat medium pipe is at least in the heat exchange flow path. Or the part located in the taper part of the said catalyst case forms a single heat carrier flow path.

  In the exhaust system heat exchanging device according to claim 8, since there is no branching or the like in the portion including the heat exchanging portion of the heat medium pipe located in the exhaust passage, the heat medium outlet is directed upward in the vertical direction for air venting. Eliminate restrictions such as. For this reason, the arrangement | positioning freedom degree of heat-medium piping with respect to an exhaust flow path becomes high.

  As described above, the exhaust system heat exchange device according to the present invention has an excellent effect that heat exchange between the exhaust and the heat medium can be performed efficiently.

  A vehicle exhaust system 10 to which an exhaust system heat exchanger according to an embodiment of the present invention is applied will be described with reference to FIGS. 1 to 3.

  FIG. 1 is a perspective view showing a schematic overall configuration of a vehicle exhaust system 10. As shown in this figure, in the vehicle exhaust system 10, a catalytic converter 12, a main muffler 14, a sub muffler 16, and a tail pipe 18 are arranged in order from the upstream side in the flow direction in which exhaust gas as exhaust gas is discharged. Yes. The sub muffler 16 may be configured to be disposed between the catalytic converter 12 and the main muffler 14 or may be configured not to include the sub muffler 16. In the following description, the terms “upstream” and “downstream” indicate upstream and downstream in the flow direction of the exhaust gas.

  The catalytic converter 12 is connected via an exhaust pipe 20 to an exhaust manifold of an internal combustion engine (not shown). The catalytic converter 12 and the main muffler 14 are connected to each other by an exhaust pipe 22. The main muffler 14 and the sub muffler 16 are connected to each other by an exhaust pipe 24. The tail pipe 18 is connected to the sub muffler 16 so as to discharge exhaust gas from the downstream opening end to the outside of the vehicle.

  As shown in FIG. 2, the catalytic converter 12 includes a catalyst carrier 26 that supports a catalyst for purifying exhaust gas, and a catalyst case 28 that houses the catalyst carrier 26. The catalyst carrier 26 has, for example, a honeycomb-like or mesh-like cross-sectional shape, and includes a large number of linear (columnar) narrow channels 26A along the exhaust gas flow direction (see arrow A). The catalyst carrier 26 purifies the exhaust gas by bringing the exhaust gas passing through each narrow channel 26A into contact with the catalyst carried in each narrow channel 26A. This catalyst removes a part or all of, for example, carbon monoxide (CO), nitrogen oxide (NOx), which is a combustion product contained in exhaust gas, and hydrocarbon (HC), which is unburned fuel. Those that promote the reaction are selected.

  The catalyst case 28 has a larger diameter than the exhaust pipes 20 and 22, a carrier holding part 30 as a catalyst part that accommodates the catalyst carrier 26, an upstream conical part 32 provided on the upstream side of the carrier holding part 30, And a downstream conical part 34 provided on the downstream side of the carrier holding part 30. The upstream conical part 32 is formed in a tapered cylindrical shape having a diameter continuously increased from the upstream side toward the downstream side, and smoothly connects the downstream end of the exhaust pipe 20 and the upstream end of the carrier holding part 30. Yes. The downstream conical part 34 is formed in a tapered cylindrical shape continuously reduced in diameter from the upstream side toward the downstream side, and smoothly connects the downstream end of the carrier holding part 30 and the upstream end of the exhaust pipe 22. Yes.

  In the catalyst case 28, each narrow channel 26 </ b> A of the catalyst carrier 26 accommodated in the carrier holding unit 30 has an upstream end opened in the upstream conical portion 32 and a downstream end opened in the downstream conical portion 34. is doing. Thus, in the catalyst case 28, the exhaust gas is rectified by being dispersed in the numerous fine channels 26A of the catalyst carrier 26 and passing through the fine channels 26A. That is, exhaust gas having a linear flow (velocity vector) along the direction of arrow A is introduced into the downstream conical portion 34.

  The vehicle exhaust system 10 is provided with an exhaust heat recovery unit 36 for recovering the exhaust heat of the exhaust gas. The exhaust heat recovery part 36 is configured by disposing a cooling water pipe 38 as a heat medium pipe in a downstream conical part 34 of the catalyst case 28 which is an exhaust gas flow path. The cooling water pipe 38 is a pipe through which the engine cooling water for cooling the internal combustion engine is circulated, and the exhaust heat recovery unit 36 uses the exhaust heat of the exhaust gas in the engine immediately after the start of the internal combustion engine. It is recovered by cooling water to improve the warm-up performance of the internal combustion engine.

  As shown in FIG. 2, the cooling water pipe 38 is a taper in which the heat exchanging portion 38 </ b> A mainly disposed in 34 has a larger winding diameter (curvature radius) on the upstream side and a smaller winding diameter toward the downstream side. It is formed in a spiral shape. Therefore, when the cooling water pipe 38 is viewed from the upstream side in the axial direction, a spiral shape having a larger curvature toward the downstream side is formed as shown in FIG.

  In this embodiment, the heat exchanging portion 38A of the cooling water pipe 38 is configured such that, in the downstream side conical portion 34, the portion located on the upstream side does not overlap the portion located on the downstream side (does not create a shadow). ing. Specifically, as shown in FIG. 3, at each position in the circumferential direction of the heat exchanging portion 38 </ b> A, the inner radius Ri that is the inner radius of curvature of the large-diameter side (exhaust gas upstream) portion is the outer curvature of the small-diameter portion. It is larger than the outer diameter Ro, which is a radius.

  As shown in FIG. 2, in a side view, the virtual bus C when the cooling water pipe 38 is assumed to be a cone and the inner peripheral surface 34 </ b> A (bus) of the downstream conical portion 34 are substantially parallel to each other. Yes. That is, the cooling water pipe 38 is disposed in the downstream conical part 34 so as to be coaxial and in the same taper direction, and the conical angle (taper angle) of the downstream conical part 34 and the cooling water pipe 38 The cone angle is approximately the same.

  The cooling water pipe 38 has an introduction part 38B that is continuous with the small-diameter side end of the heat exchange part 38A that is formed in a tapered spiral shape, and a lead-out part 38C that is continuous with the large-diameter side end of the heat exchange part 38A. The introduction portion 38B penetrates the boss portion 40 provided on the downstream end side of the downstream side conical portion 34 and is introduced into the downstream side conical portion 34 from the outside of the catalyst case 28. On the other hand, the lead-out portion 38 </ b> C passes through the boss portion 42 provided on the upstream end side of the downstream-side conical portion 34 and is led out from the downstream-side conical portion 34 to the outside of the catalyst case 28.

  Then, as indicated by an arrow B in each figure, the cooling water pipe 38 is configured so that the engine cooling water is introduced from the introduction portion 38B, passes through the heat exchange portion 38A, and the engine cooling water is discharged from the outlet portion 38C. It has become. Further, in this cooling water pipe 38, a heat exchange part 38A, an introduction part 38B, and a lead-out part 38C are integrally formed to form a single (single) flow path, and a branch is formed in the downstream conical part 34. It is set to not be. In this embodiment, the cooling water pipe 38 is formed by bending the pipe material.

  Next, the operation of this embodiment will be described.

  In the vehicle exhaust system 10 configured as described above, the exhaust gas of the internal combustion engine is discharged from the tail pipe 18 through the exhaust pipe 20, the catalytic converter 12, the exhaust pipe 22, the main muffler 14, the exhaust pipe 24, and the sub muffler 16.

  At this time, in the catalyst case 28 constituting the catalytic converter 12, the exhaust gas is rectified by passing through a large number of narrow channels 26 </ b> A of the catalyst carrier 26, and this rectified exhaust gas flow flows into the downstream conical part 34. To do. In the downstream conical portion 34, exhaust gas that flows from the upstream side to the downstream side in the downstream conical portion 34 and engine cooling water that flows in the cooling water pipe 38 disposed in the downstream side conical portion 34. And heat exchange is performed. Thereby, after the internal combustion engine engine is started, the engine is warmed up early.

  Here, in the exhaust heat recovery part 36 of the vehicle exhaust system 10, the heat exchange part 38 </ b> A formed in a tapered spiral shape in the cooling water pipe 38 is an upstream side of the exhaust gas flow in a wide area in the downstream side conical part 34. Therefore, the heat exchange between the exhaust gas and the engine coolant is efficiently performed, and the exhaust heat of the exhaust gas is recovered in the engine coolant. In addition, since the exhaust gas that has been rectified and flows linearly through the catalyst carrier 26 contacts the heat exchanging portion 38A substantially uniformly in each radial portion of the downstream conical portion 34, the exhaust heat of the exhaust gas is reduced to the engine cooling water. Can be recovered more efficiently.

  In particular, since the heat exchanging portion 38A has a spiral shape in which the upstream portion does not overlap the downstream portion when viewed from the axial direction, the exhaust gas contacts the heat exchanging portion 38A evenly and the exhaust heat of the exhaust gas is reduced. More efficiently recovered in engine cooling water. In particular, since the heat exchanging portion 38A formed in a tapered spiral shape is coaxially disposed in the corresponding downstream conical portion 34 formed in a tapered cylindrical shape, in other words, the diameter of the heat exchanging portion 38A. Since it is difficult for the exhaust gas to escape to the outside in the direction, the exhaust heat of the exhaust gas is more efficiently recovered into the engine coolant.

  Further, in the exhaust heat recovery unit 36 of the vehicle exhaust system 10, the engine is cooled from the small diameter side (in the present embodiment, the exhaust gas downstream side) located on the center (axial center) side of the downstream conical part 34 in the heat exchange unit 38A. Since water is introduced, the high-temperature exhaust gas flowing through the central portion of the downstream conical portion 34 exchanges heat with the low-temperature engine cooling water. For this reason, the efficiency of heat recovery is improved, and the temperature of the engine coolant can be raised in a short time. Further, the exhaust gas is greatly cooled at the central portion of the downstream conical portion 34, and the temperature distribution in the radial direction is made uniform. Similarly, the engine coolant has a uniform temperature distribution in the flow direction (the radial direction of the spiral viewed from the axial direction).

  Thus, the exhaust heat recovery part 36 applied to the vehicle exhaust system 10 according to the present embodiment can efficiently perform heat exchange between the exhaust gas and the engine coolant.

  In the exhaust heat recovery section 36 of the vehicle exhaust system 10, the tapered spiral heat exchange section 38A is coaxially disposed in the corresponding downstream conical section 34 formed in the corresponding tapered cylindrical shape as described above. Therefore, as compared with a configuration in which a spiral heat exchange pipe extending along the cylindrical surface is disposed in the central portion of the downstream conical portion 34, the exhaust flow is prevented from being hindered, and the exhaust resistance (back pressure) is reduced. Can be suppressed.

  Furthermore, in the exhaust heat recovery part 36 of the vehicle exhaust system 10, the cooling water pipe 38 forms a single cooling water flow path without branching, so that the introduction part 38B and the outlet part 38C are arranged on the downstream side in order to vent the air. There is no restriction such as taking out the conical part 34 in the vertical direction. For this reason, the arrangement | positioning freedom degree of the cooling water piping 38 with respect to the downstream conical part 34 becomes high.

  Further, in the exhaust heat recovery part 36 of the vehicle exhaust system 10, the heat exchange part 38A of the cooling water pipe 38 is disposed immediately downstream of the catalyst carrier 26 that exerts the exhaust gas rectifying action, so that a separate rectifier is not provided. As described above, efficient exhaust heat recovery can be performed.

  In the above embodiment, an example in which the heat exchanging portion 38A is formed in a tapered spiral shape corresponding to the arranged downstream conical portion 34 is shown, but the present invention is not limited to this, and for example, FIG. As shown in (A), a tapered spiral heat exchange section 38 </ b> A may be disposed in the cylindrical exhaust pipe 50. Further, for example, in the configuration in which the heat exchanging portion 38A is disposed in the cylindrical exhaust pipe 50, the small diameter side of the heat exchanging portion 38A may be positioned upstream of the exhaust gas. From these, it is understood that the taper angle of the heat exchanging part 38A does not have to coincide with the taper angle of the downstream conical part 34 according to the present invention.

It is a perspective view which shows the exhaust system for vehicles which concerns on embodiment of this invention. It is a sectional side view which shows the exhaust heat recovery part which comprises the exhaust system for vehicles which concerns on embodiment of this invention. It is the front view which looked at the heat exchange part in the cooling water piping which comprises the exhaust-heat recovery part of the exhaust system for vehicles which concerns on embodiment of this invention from the axial direction upstream. It is a figure which shows the modification of the exhaust heat recovery part which comprises the exhaust system for vehicles which concerns on embodiment of this invention, Comprising: (A) is sectional drawing which shows a 1st modification, (B) is a 2nd modification. It is sectional drawing shown.

Explanation of symbols

10 Vehicle exhaust system (exhaust system)
26 Catalyst carrier (catalyst)
26A Narrow channel 28 Catalyst case 30 Carrier holding part (catalyst part)
34 Downstream conical part (exhaust flow path, heat exchange flow path, taper part)
36 Exhaust heat recovery unit (exhaust heat exchanger)
38 Cooling water piping (heat medium piping)
38A Heat exchange section 50 Exhaust pipe (exhaust flow path, heat exchange flow path)

Claims (8)

An exhaust system heat exchange device that arranges a heat medium pipe in the exhaust system and performs heat exchange between the heat medium flowing through the heat medium pipe and the exhaust,
In the heat medium pipe, the heat exchange part formed in a spiral shape in an axial view so that the curvature continuously changes from the upstream side to the downstream side in the exhaust flow direction is an exhaust flow that constitutes the exhaust system. An exhaust system heat exchange device arranged coaxially in the road. An exhaust system heat exchange device that arranges a heat medium pipe in the exhaust system and performs heat exchange between the heat medium flowing through the heat medium pipe and the exhaust,
The exhaust system includes a rectification unit that rectifies the exhaust flow, and a heat exchange channel that is continuous downstream of the rectification unit in the exhaust flow direction,
In the heat medium pipe, a heat exchange part formed in a spiral shape in an axial view so that the curvature continuously changes from the upstream side to the downstream side in the exhaust flow direction is coaxial with the heat exchange channel. Exhaust system heat exchanger.   The exhaust system heat exchange device according to claim 2, wherein the rectifying unit is a catalyst in which a large number of linear narrow channels along the exhaust flow direction are arranged in parallel. An exhaust system heat exchange device that arranges a heat medium pipe in the exhaust system and performs heat exchange between the heat medium flowing through the heat medium pipe and the exhaust,
The exhaust system has a catalyst case that contains a catalyst in which a large number of linear narrow channels along the exhaust flow direction are arranged in parallel,
The catalyst case includes a catalyst portion that accommodates the catalyst, and a tapered portion that is formed continuously in a taper shape on the downstream side in the exhaust flow direction of the catalyst portion,
In the catalyst case, the heat exchange pipe is formed in a spiral spiral shape having a spiral shape as viewed in the axial direction so that the curvature continuously changes from the upstream side to the downstream side in the exhaust flow direction. An exhaust system heat exchange device arranged coaxially and in a taper direction within the taper portion.   The exhaust heat exchanger according to claim 4, wherein the heat exchange part of the heat medium pipe has a taper angle that matches a taper angle of an inner peripheral surface of the taper part of the catalyst case.   6. The heat exchange part of the heat medium pipe according to claim 1, wherein the inner diameter of the large-diameter side portion is larger than the outer diameter of the small-diameter side portion at the same position in the circumferential direction. Exhaust system heat exchanger.   The exhaust heat exchanger according to any one of claims 1 to 6, wherein a heat medium is introduced into a heat exchanging part of the heat medium pipe from a side having a large curvature.   8. The heat medium pipe according to claim 1, wherein at least a portion of the heat medium pipe located in the heat exchange flow path or in the taper portion of the catalyst case forms a single heat medium flow path. Exhaust system heat exchanger.

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