JP2011256783A - Heat exchange unit and method for manufacturing of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchange unit by which manufacturing cost can be reduced without lowering heat exchanging effect.SOLUTION: The heat exchange unit (23) arranged in a channel (20) of exhaust gas of the internal combustion engine (10) and carrying out heat exchange between the exhaust gas and medium includes the first case (41) and the second case (42) constituted by bisecting the cylindrical shape case (40) by the plane parallel to the flowing direction of the exhaust gas, the heat exchanger (32) housed in the first case (41) and carrying out heat exchange between the exhaust gas and the medium flowing the inside thereof, a bypass passage (34) formed in the second case (42) and passing the exhaust gas therethrough, the on-off valve (35) for switching passing the exhaust gas through the heat exchanger (32) or through the bypass passage (34), and the first case (41) and the second case (41) are connected.

Description

  The present invention relates to a heat exchange unit used for exhaust gas piping and the like, and more particularly to a heat exchange unit capable of reducing manufacturing costs and a method for manufacturing the same.

  Conventionally, by recovering heat from the exhaust gas of an internal combustion engine mounted on a vehicle and using this thermal energy for other purposes (warming up the internal combustion engine, heating the vehicle interior and generating electricity), the fuel efficiency of the internal combustion engine is improved. Things to enhance are known. In addition, there is also known an EGR that recirculates a part of exhaust gas to the intake side of the internal combustion engine to increase the fuel efficiency of the internal combustion engine by reducing the temperature of the recirculated exhaust gas.

  The heat of the exhaust gas is generally exchanged between the exhaust gas and the medium by providing a heat exchanger in the middle of the exhaust gas passage and passing a medium such as cooling water of the internal combustion engine through the heat exchanger. In this case, depending on the operating state of the internal combustion engine, it may not be appropriate to always perform heat exchange.

  Therefore, it is common to provide the exhaust gas passage with a passage to the heat exchanger and a passage that bypasses the passage, and a switching valve is provided to adjust the flow rate of the exhaust gas to the heat exchanger.

  As such a heat exchanger, there is disclosed an exhaust gas cooling device (see Patent Document 1) capable of selecting whether the exhaust gas flow passes through the exchanger means or is discharged without passing through the exchanger means by a flap. .

  In addition, a substantially annular exhaust heat recovery passage for circulating cooling water along the outer peripheral surface is provided on the outer peripheral surface of the inner cylinder portion, and an inner exhaust gas passage is provided from the inner cylinder portion to the inside of the exhaust heat recovery passage. An exhaust heat recovery device for an internal combustion engine provided with an outer exhaust gas passage branched through the exhaust gas passage is disclosed (see Patent Document 2).

Special table 2009-523944 JP 2009-24565 A

  In the configurations disclosed in Patent Document 1 and Patent Document 2 described above, a heat exchanger and a bypass passage are arranged in a cylindrical case. In this case, it is necessary to assemble a heat exchanger or a switching valve having a complicated shape from the opening portions at both ends of the cylinder, and the workability is not high, so the number of work steps increases and the manufacturing cost increases.

  Further, as in Patent Document 1 described above, when the exhaust gas passage is in contact with the heat exchanger, the heat of the exhaust gas is transmitted to the heat exchanger even when the exhaust gas flows through the bypass passage. Therefore, since a large amount of exhaust gas is discharged at a high temperature at a high load of the engine, heat is transferred to the cooling water even when recovery is not appropriate, and the cooling water temperature may rise more than necessary.

  In addition, when the heat exchanger and the bypass passage are double pipes as in the above-mentioned Patent Document 2, since the overall length is shortened, the mountability on the vehicle in this direction is improved. Therefore, when it is arranged under the floor of the vehicle body, the mountability deteriorates due to the gap with the ground. Further, the exhaust gas flow path on the heat exchanger side is bent and complicated, the exhaust gas flow cross-sectional area is limited, the back pressure increases, and the engine operating efficiency may decrease.

  This invention is made | formed in view of such a problem, and it aims at providing the heat exchange unit which can reduce manufacturing cost, without reducing heat exchange efficiency.

  A first aspect of the present application is a heat exchange unit that is installed in an exhaust gas passage of an internal combustion engine and performs heat exchange between the exhaust gas and a medium, and a cylindrical case on a surface parallel to the flow direction of the exhaust gas. A first case and a second case divided into two parts, a heat exchanger that is accommodated in the first case and exchanges heat between the exhaust gas and the medium circulating inside, and formed in the second case, A bypass passage for passing through, and a switching valve for switching exhaust gas to flow through the heat exchanger or through the bypass passage, and configured by joining the first case and the second case. It is characterized by that.

  According to a second aspect, in the first aspect, the bypass passage includes a bypass pipe that is accommodated in the second case and disposed at a predetermined interval from the heat exchanger.

  A third aspect is characterized in that, in the first or second aspect, a partition member having a heat insulating structure is provided between the heat exchanger and the bypass passage.

  According to a fourth aspect, in the first to third aspects, the heat exchanger is configured such that one of the exhaust gas flow directions is joined to the first case and the other of the exhaust gas flow directions is stretched via a stretchable member. It is supported by a case.

  A fifth aspect is a method of manufacturing a heat exchange unit that is installed in an exhaust gas passage of an internal combustion engine and performs heat exchange between the exhaust gas and a medium, wherein a cylindrical case is parallel to the flow direction of the exhaust gas. A step of preparing the first case and the second case divided in two, a step of accommodating a heat exchanger for exchanging heat between the exhaust gas and a medium circulating in the first case, and a second case A step of forming a bypass passage in the case for passing the exhaust gas, a step of arranging a switching valve switching valve for switching whether the exhaust gas is circulated through the heat exchanger or the bypass passage in the second case, And a step of joining the first case and the second case.

  According to the first aspect, since the case, the first case, and the second case are divided into two, the opening of the case is widened, and the assembly of the components accommodated therein is facilitated, so that the assembling property is improved. . Moreover, since a heat exchange unit is comprised only by joining a 1st case and a 2nd case, an operation man-hour can be reduced and manufacturing cost can be reduced.

  According to the second aspect, since the bypass pipe is accommodated in the bypass passage, the bypass passage has a double structure by the bypass pipe, and reliably prevents heat transfer to the heat exchanger when heat exchange is unnecessary. The operating efficiency of the internal combustion engine can be improved.

  According to the third aspect, since the heat insulating structure is provided between the heat exchanger and the bypass passage, the heat transfer to the heat exchanger is prevented when the heat exchange is unnecessary, and the operation efficiency of the internal combustion engine is improved. It can be improved.

  According to the 4th aspect, it can prevent that the stress by heat acts on a heat exchanger, and can improve durability of a heat exchange unit.

  According to the fifth aspect, since the case is divided into the first case and the second case in parallel with the exhaust gas flow direction, the opening of the case is widened and it is easy to assemble the components inside. Therefore, the assembling property is improved. Moreover, since a heat exchange unit is comprised only by joining a 1st case and a 2nd case, work man-hours can be reduced by reducing a welding part, and manufacturing cost can be reduced.

It is explanatory drawing of the drive system centering on the engine of the 1st Embodiment of this invention. It is sectional drawing of the heat exchange unit of the 1st Embodiment of this invention. It is a disassembled perspective view of the heat exchange unit of the 1st Embodiment of this invention. It is sectional drawing of the heat exchange unit of the 2nd Embodiment of this invention. It is sectional drawing of another example of the heat exchange unit of the 2nd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
FIG. 1 is an explanatory diagram of a drive system centering on an engine 10 according to a first embodiment of the present invention.

  The drive system of this embodiment drives a vehicle by an engine 10 mounted on the vehicle.

  The engine 10 as an internal combustion engine obtains a rotational driving force by explosively burning a fuel mixture of air and vaporized fossil fuel. The exhaust gas that has become high temperature after the explosion combustion is discharged to the atmosphere through the manifold 12 and the exhaust pipe 20.

  The engine 10 is provided with a cooling water system 100 for keeping the engine 10 at an appropriate temperature. The cooling water system 100 includes a radiator 11, a heater 13, a water pump 101, and a thermostat 102.

  The cooling water circulated in the cooling water system 100 by the water pump 101 dissipates heat by exchanging heat with the atmosphere in the radiator 11, is appropriately cooled, and keeps the engine 10 at an appropriate temperature. The thermostat 102 is closed when the cooling water temperature is equal to or lower than a predetermined temperature, and does not dissipate heat by bypassing the radiator 11, thereby promoting engine warm-up. The heater 13 heats the passenger compartment using the remaining heat of the cooling water.

  The exhaust pipe 20 includes a manifold 12, a catalyst 21, an upstream pipe 22, a heat exchange unit 23, a downstream pipe 25, a silencer 27, and a tail pipe 28.

  The exhaust gas discharged from the engine 10 is purified by the catalyst 21 through the manifold 12. An upstream pipe 22 is connected to the downstream side of the catalyst 21. A heat exchange unit 23 is connected to the downstream side of the upstream pipe 22. The heat exchange unit 23 performs heat exchange between the exhaust gas discharged from the engine 10 and the cooling water flowing inside.

  By this heat exchange, it is possible to raise the cooling water temperature and lower the exhaust gas temperature. The engine 10 can be warmed up by raising the cooling water temperature, and the heat energy of the cooling water can be used for other purposes (eg heating the passenger compartment or generating electricity by converting heat energy into kinetic energy). The fuel efficiency of the engine 10 can be improved. Moreover, the silencing effect of the silencer 27 can be enhanced by lowering the exhaust gas temperature.

  The exhaust gas that has passed through the heat exchange unit 23 is silenced by the silencer 27 via the downstream pipe 25 and then discharged from the tail pipe 28.

  The heat exchange unit 23 includes a branch portion 31, a heat exchanger 32, a junction portion 33, a bypass passage 34, a switching valve 35, and a partition plate 36.

  The branch portion 31 includes a switching valve 35 that switches between sending exhaust gas to the heat exchanger 32 or sending it to the bypass passage 34.

  The heat exchanger 32 performs heat exchange between the introduced medium and the exhaust gas. The heat exchanger 32 is connected to the cooling water system 100 of the engine 10 and uses cooling water as a medium. In addition, you may connect the cooling water path | route (For example, the battery in a hybrid system, or the cooling water path | route of a control circuit) different from the cooling water system | strain 100 of a drive system to the heat exchanger 32. Further, the medium is not limited to cooling water, and for example, chlorofluorocarbons or carbon dioxide may be used.

  The bypass passage 34 serves as an exhaust gas exhaust passage when the exhaust gas does not flow to the heat exchanger 32. The branch portion 31 is provided with a switching valve 35 that allows the exhaust gas to flow through the heat exchanger 32 or the bypass passage 34 so that the shaft 38 can rotate.

  Whether the exhaust gas is circulated through the heat exchanger 32 or the bypass passage 34 is determined by the operating state of the engine 10, the temperature of the coolant that is the medium, and the like. For example, since the exhaust gas temperature and the cooling water temperature are high when the engine 10 is heavily loaded, the exhaust gas is bypassed without performing heat exchange in order to prevent overheating due to an increase in the cooling water temperature.

  Between the heat exchanger 32 and the bypass passage 34, the partition plate 36 (partition member) which partitions these is provided.

  The exhaust gas that has passed through the heat exchanger 32 or the bypass passage 34 is discharged to the downstream pipe 25 through the junction 33.

  In the present embodiment, the upstream side in the exhaust gas flow direction is simply referred to as the upstream side, and the downstream side in the exhaust gas flow direction is simply referred to as the downstream side.

  Next, a more specific configuration of the heat exchange unit 23 will be described.

  FIG. 2 is a sectional view of the heat exchange unit 23 according to the first embodiment of the present invention, and FIG. 3 is an exploded perspective view of the heat exchange unit 23.

  As described above, the heat exchange unit 23 is configured such that the heat exchanger 32, the bypass passage 34, the switching valve 35, and the partition plate 36 are accommodated in the cylindrical case 40.

  The case 40 is constituted by an upper case (first case) 41 and a lower case (second case) 42 that are divided into two by a plane parallel to the flow direction of the exhaust gas. In other words, the upper case 41 and the lower case 42 are divided into two in a direction perpendicular to the flow direction of the exhaust gas.

  The heat exchanger 32 is accommodated in the upper case 41. The heat exchanger 32 is connected to a cooling water introduction pipe and a discharge pipe (not shown), and is connected to the cooling water system 100 between the heat exchanger 32 and the engine 10 on the downstream side of the heater 13. The heat exchanger 32 is configured such that a large number of flat gas passages 32a pass through in the exhaust gas flow direction, and cooling water as a medium flows around the gas passages 32a. The flow direction of the cooling water and the exhaust gas may be a counter flow or a parallel flow.

  The bypass passage 34 is configured by accommodating a bypass pipe 39 in a lower case 42 of the case 40. The bypass pipe 39 opens to the upstream side while curving upward (to the heat exchanger 32 side) as it goes toward the upstream end along the outer shape of the lower case 42. On the upper side of the opening portion on the upstream side, a flat planar portion 39a that contacts the partition plate 36 is formed.

  Further, the bypass pipe 39 extends to the downstream side in substantially the same direction as the exhaust gas flow direction, and opens to the merging portion 33.

  The partition plate 36 is a flat plate member interposed between the heat exchanger 32 and the bypass pipe 39.

  The partition plate 36 is in contact with the flat portion 39a where the heat exchanger 32 is not provided on the upstream side of the bypass pipe 39, but at the position corresponding to the gas passage 32a that performs heat exchange in the heat exchanger 32, the partition plate 36 is bypassed. Due to the bending of the tube 39, a predetermined gap is formed between the bypass tube 39 and the partition plate 36. A slight gap is also formed between the heat exchanger 32 and the partition plate 36. The heat exchanger 32 and the bypass pipe 39 are configured not to be in direct contact with each other due to the offset and gap of the contact portion between the heat exchange 32 and the bypass pipe 39.

  Further, on the downstream side of the partition plate 36 in the exhaust gas flow direction, a support portion 36b that supports the bypass pipe 39 is formed with a predetermined gap from a position corresponding to the gas passage 32a of the heat exchanger 32.

  With such a configuration, a predetermined gap is formed between the heat exchanger 32 and the bypass pipe 39. Gas (exhaust gas) is present in this gap. This gas does not move much because it is out of the main stream of exhaust gas. Further, since the gas has a low thermal conductivity, the heat of the exhaust gas from the bypass pipe 39 can be prevented from being transmitted to the heat exchanger 32. That is, the joint is located at a position away from the heat exchanger 32, and a predetermined gap is formed between the heat exchanger 32 and the bypass pipe 39 by the partition plate 36, so that a heat insulating structure is configured. .

  The branch portion 31 of the heat exchange unit 23 is provided with a switching valve 35 for circulating the exhaust gas through one of the heat exchanger 32 and the bypass passage 34.

  The switching valve 35 is rotatably supported by a shaft 38. The shaft 38 is fixed to a bearing hole 42b formed in the lower case 42 via a bearing 38a. The switching valve 35 is rotated by rotationally driving the shaft 38 by an actuator such as a motor or a solenoid (not shown).

  Flange 43a, 43b for connecting with the upstream pipe 22 and the downstream pipe 25 is joined to the upstream and downstream ends of the case 40, respectively.

  The heat exchange unit 23 is manufactured as follows.

  As shown in FIG. 3, the heat exchange unit 23 includes a case 40 including an upper case 41 and a lower case 42, and a heat exchanger 32, a bypass pipe 39, a switching valve 35, and a partition plate 36 are accommodated in the case 40. Is done.

  First, after the heat exchanger 32 is accommodated in the upper case 41 in advance, these are joined by welding or the like. At this time, only the upstream side of the heat exchanger 32 is joined to the upper case 41, and the downstream side of the heat exchanger 32 is wound around a metal mesh 44 a that is a stretchable member around the heat exchanger 32. The upper case 41 supports the heat exchanger 32 through this member.

  Further, after the bypass pipe 39 is accommodated in the lower case 42 in advance, these are joined by welding or the like. At this time, similarly to the upper case 41, only the upstream side of the bypass pipe 39 is joined to the lower case 42, and the downstream side of the bypass pipe 39 has a metal mesh 44 b that is a stretchable member around the bypass pipe 39. Wind around. The lower case 42 supports the bypass pipe 39 through this member.

  Next, after the switching valve 35 and the shaft 38 are assembled to the lower case 42, the partition plate 36 is sandwiched between the upper case 41 and the lower case 42, and these are joined by welding or the like. Thereafter, the flanges 43a and 43b, the entrance and exit of the medium to the heat exchanger 32, and the like are joined by welding or the like.

  The heat exchange unit 23 is manufactured by such a procedure.

  The heat exchange unit 23 according to the first embodiment of the present invention configured as described above has the following effects.

  In the heat exchange unit 23, the case 41 is composed of an upper case 41 and a lower case 42 which are divided into two in the horizontal direction with respect to the flow direction of the exhaust gas. Workability is improved. Since the upper case 41 that accommodates the heat exchanger 32 and the lower case 42 that accommodates the bypass pipe 39 are joined by sandwiching the partition plate 36, the number of work steps such as welding is reduced. It is possible to reduce the manufacturing cost. Moreover, since it becomes possible to make the junction part of both cases linear, by this, it becomes possible to reduce a welding work location, to facilitate welding work, and to shorten the welding length.

  Further, since the heat exchanger 32 and the bypass passage 34 are arranged in parallel, there is no configuration that prevents the flow of exhaust gas to the heat exchanger 32, and the overall length of the heat exchange unit 23 is reduced without reducing the heat exchange efficiency. And can be mounted on a vehicle.

  Further, the heat exchanger 32 and the bypass passage 34 are configured so as not to be in direct contact with each other by the partition plate 36, and have a heat insulating structure with gas (exhaust gas) between them. With this heat insulating structure, for example, heat can be prevented from being transferred from the bypass pipe 39 to the heat exchanger 32 at the time of bypass in which exhaust gas is circulated to the bypass passage 34. Therefore, it is possible to prevent the temperature of the cooling water from rising more than necessary, and to prevent overheating of the engine due to an increase in water temperature, for example.

  Further, the exhaust gas flows through the exhaust pipe 20 at a temperature from normal temperature (immediately after starting the engine) to 700 to 800 degrees (when the engine is highly loaded). For this reason, each member of the exhaust pipe may be damaged due to the stress due to thermal expansion applied to the joint portion.

  In the heat exchange unit 23 of the present embodiment, the heat exchanger 32 and the bypass pipe 39 provided in the flow passage through which the exhaust gas flows are joined to only one of the gas flow directions, and the other is supported by a stretchable member. It can absorb stress due to thermal expansion and prevent damage due to stress.

  Further, at the time of heat recovery in which the exhaust gas is circulated to the heat exchanger 32, there is no configuration that hinders the distribution of the exhaust gas to the heat exchanger 32, so that the heat recovery efficiency can be increased.

  In addition, since the cooling water flows on the heat exchanger side, the case 41 does not reach a high temperature, and the case 42 on the bypass passage 34 side also has a double structure due to the bypass pipe 39 and thus does not reach a high temperature. Since the thermal influence on the surroundings of the replacement unit 23 can be minimized, the degree of freedom of the installation location of the electrical components that should be heat-resistant such as the solenoid and actuator that drive the switching valve 35 is increased.

Second Embodiment
Next, a second embodiment of the present invention will be described.

  In the second embodiment, the configuration of the bypass passage 34 is different. The basic configuration (FIG. 1) of the first embodiment is common. Moreover, the same code | symbol is attached | subjected to the structure same as 1st Embodiment, and the description is abbreviate | omitted.

  FIG. 4 is a cross-sectional view of the heat exchange unit 23 according to the second embodiment of the present invention.

  In the heat exchange unit 23, the lower case 42 is not provided with the bypass pipe 39, and the lower case 42 itself is used as a bypass passage 34 serving as an exhaust gas passage during bypass.

  The heat exchange unit 23 of the second embodiment is manufactured in the same manner as in the first embodiment.

  First, after the heat exchanger 32 is accommodated in the upper case 41 in advance, these are joined by welding or the like. At this time, only the upstream side of the heat exchanger 32 is joined to the upper case 41, and the downstream side of the heat exchanger 32 is wound around a metal mesh 44 a that is a stretchable member around the heat exchanger 32. The upper case 41 supports the heat exchanger 32 through this member.

  Next, after the switching valve 35 and the shaft 38 are assembled to the lower case 42, the partition plate 36 is sandwiched between the upper case 41 and the lower case 42, and these are joined by welding or the like. Thereafter, the flanges 43a and 43b, the entrance / exit of the medium to the heat exchanger 32, and the like are joined.

  The heat exchange unit 23 is manufactured by such a procedure.

  In the second embodiment, the heat exchanger 32 contacts the bypass passage 34 only through the partition plate 36. For this reason, a gap is formed between the heat exchanger 32 and the partition plate 36, and a gas (exhaust gas) is interposed in the gap to obtain a heat insulating structure.

  On the other hand, when the exhaust capacity of the engine 10 is large and the heat capacity of the exhaust gas is relatively large and the heat recovery device receives a lot of heat, the partition plate 36 may have a double structure as shown in FIG.

  Specifically, in the heat exchange unit 23 of FIG. 5, the partition plate 36 is provided on the bypass passage 34 side with a first plate 361 in contact with the heat exchanger 32 and a predetermined gap from the first plate 361. It has a double structure with the second plate 362. The portion in contact with these is offset from the heat exchanger 32, and the heat exchanger 32 and the bypass passage 34 are not directly in contact with each other by the gap. A heat insulating structure is configured by interposing a gas (exhaust gas) in the gap.

  The heat exchange unit 23 according to the second embodiment of the present invention configured as described above has the following effects.

  As in the first embodiment, the case 41 is composed of an upper case 41 and a lower case 42 that are divided into two in a horizontal plane with respect to the flow direction of the exhaust gas. Since it becomes easy to assemble, workability is improved. Since the upper case 41 that accommodates the heat exchanger 32 and the lower case 42 that accommodates the bypass pipe 39 are joined by sandwiching the partition plate 36, the number of work steps such as welding is reduced. It is possible to reduce the manufacturing cost. Moreover, since it becomes possible to make the junction part of both cases linear, by this, it becomes possible to reduce a welding work location, to facilitate welding work, and to shorten the welding length.

  Similarly to the first embodiment, the heat exchanger 32 is bonded to only one of the gas flow directions, and the other is supported by a stretchable member, thereby absorbing the stress due to thermal expansion. Breakage can be prevented.

  Further, by providing a heat insulating structure by interposing a gas (exhaust gas) between the heat exchanger 32 and the bypass passage 34, it is possible to prevent the heat of the exhaust gas from being transmitted to the heat exchanger 32 during the bypass. It is possible to prevent the water from rising more than necessary, and for example to prevent overheating due to an increase in water temperature.

  Further, at the time of heat recovery in which the exhaust gas is circulated to the heat exchanger 32, there is no configuration that hinders the distribution of the exhaust gas to the heat exchanger 32, so that the heat recovery efficiency can be increased.

  In the first and second embodiments described above, the heat exchanger 32 and the bypass passage 34 are configured to prevent heat transfer by interposing a gas with the partition plate 36. On the other hand, between the heat exchanger 32 and the bypass passage 34, you may fill with the heat insulating material which consists of glass fiber, a steel mesh, etc., for example. Thereby, while being able to make a heat insulation effect higher than comprised only with gas, a vibration and a thermal stress can be absorbed and durability can be improved.

  In the present invention, the configuration in which the heat of the exhaust gas of the engine 10 is recovered by cooling water as shown in FIG. 1 is described as an example, but the present invention is not limited to this. For example, the heat exchange unit 23 of the present embodiment may be applied to EGR that recirculates exhaust gas from the engine 10 to the intake side of the engine 10.

  By applying the heat exchange unit 23 of the present embodiment to the EGR, the exhaust gas that is recirculated and the cooling water can be subjected to heat exchange to lower the exhaust gas temperature. Fuel efficiency can be improved.

DESCRIPTION OF SYMBOLS 10 Engine 20 Exhaust pipe 23 Heat exchange unit 32 Heat exchanger 34 Bypass path 35 Switching valve 36 Partition plate 39 Bypass pipe 40 Case 41 Upper case 42 Lower case

Claims (5)

A heat exchange unit that is installed in an exhaust gas passage of an internal combustion engine and performs heat exchange between the exhaust gas and a medium,
A first case and a second case obtained by dividing the cylindrical case into two parts in a plane parallel to the flow direction of the exhaust gas;
A heat exchanger housed in the first case and performing heat exchange between the exhaust gas and the medium flowing inside;
A bypass passage formed in the second case and allowing the exhaust gas to pass through;
A switching valve that switches whether the exhaust gas is circulated through the heat exchanger or the bypass passage;
With
A heat exchange unit comprising the first case and the second case joined together. The heat exchange unit according to claim 1,
The bypass passage is provided in the second case, and includes a bypass pipe disposed at a predetermined interval from the heat exchanger. In the heat exchange unit according to claim 1 or 2,
A heat exchange unit comprising a partition member having a heat insulating structure between the heat exchanger and the bypass passage. In the heat exchange unit according to any one of claims 1 to 3,
The heat exchanger is characterized in that one of the exhaust gas flow directions is joined to the first case, and the other of the exhaust gas flow directions is supported by the first case via a stretchable member. Replacement unit. A method of manufacturing a heat exchange unit that is installed in an exhaust gas passage of an internal combustion engine and performs heat exchange between the exhaust gas and a medium,
Preparing a first case and a second case obtained by dividing a cylindrical case into two parts in a plane parallel to the flow direction of the exhaust gas;
A step of accommodating a heat exchanger that performs heat exchange between the exhaust gas and the medium circulating inside in the first case;
Forming a bypass passage for allowing the exhaust gas to pass through the second case;
Disposing a switching valve in the second case for switching between flowing the exhaust gas to the heat exchanger or the bypass passage;
Joining the first case and the second case;
A method for manufacturing a heat exchange unit, comprising:

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