JP2020020330A - Exhaust heat recovery device - Google Patents

Abstract

To provide an exhaust heat recovery device capable of suppressing heat damage to a thermo-actuator caused by steam.SOLUTION: An exhaust heat recovery device in this disclosure includes: a heat exchange section for exchanging heat between exhaust gas of an internal combustion engine with cooling water; a valve for controlling supply amount of the exhaust gas to the heat exchange section; a thermo-actuator having a thermal expansion section expanded/contracted by heat of the cooling water, a casing accommodating the thermal expansion section, a sealing body for sealing a portion between the thermal expansion section and the casing and an output section for opening/closing the valve through expansion/contraction of the thermal expansion section; and a first water passage port and a second water passage port which constitute both ends of a flow passage of the cooling water. The first water passage port disposed below the thermo-actuator. The uppermost part of an inner surface of piping constituting the flow passage of the cooling water from the thermo-actuator to the second water passage port is located above the thermal expansion section and the sealing body.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to an exhaust heat recovery device.

  2. Description of the Related Art An exhaust heat recovery device that recovers heat of exhaust gas in an internal combustion engine for a vehicle by using cooling water is known. The exhaust heat recovery device is provided in an exhaust gas exhaust passage. The exhaust heat recovered by the cooling water in the exhaust heat recovery unit is used for heating the interior of the vehicle, warming up the internal combustion engine, and the like.

  In such an exhaust heat recovery device, a valve for adjusting the amount of exhaust gas supplied to the heat exchange section of the exhaust heat recovery device is provided in order to adjust the amount of exhaust heat recovered in accordance with the temperature of the exhaust gas. Is known (see Patent Document 1).

  The valve is opened and closed by a thermoactuator that operates according to the temperature of the cooling water. The thermoactuator opens and closes a valve by expansion and contraction of a thermal expansion body such as wax.

JP 2010-31669 A

  In a general internal combustion engine, when the internal combustion engine stops, the circulation of the cooling water also stops. Therefore, when the internal combustion engine is stopped in a state where the temperature of the exhaust gas is high due to, for example, an idling stop operation, cooling water in the exhaust heat recovery unit receives heat from peripheral components and the atmosphere, and steam is generated in the exhaust heat recovery unit. I do.

  If this water vapor stays in the exhaust heat recovery unit in a state of being in contact with resin parts such as a thermal expansion body and a sealing body of a thermoactuator, the high heat may cause these resin members to be melted or deteriorated by heat damage. There is. As a result, a malfunction of the thermoactuator may occur.

  An object of one aspect of the present disclosure is to provide an exhaust heat recovery device that can suppress heat damage to a thermoactuator due to water vapor.

  One aspect of the present disclosure is a heat exchange unit that performs heat exchange between exhaust gas of an internal combustion engine and cooling water, a valve that adjusts an amount of exhaust gas supplied to the heat exchange unit, and a valve that expands and contracts by heat of the cooling water. A thermo-actuator having a thermal expansion section, a casing accommodating the thermal expansion section, a sealing body for sealing between the thermal expansion section and the casing, and an output section for opening and closing a valve by expansion and contraction of the thermal expansion section; And a first water passage and a second water passage constituting both ends of the flow path of the exhaust gas. The first water inlet is disposed below the thermoactuator. The uppermost part of the inner surface of the pipe constituting the flow path of the cooling water from the thermoactuator to the second water inlet is located above the thermal expansion part and the sealing body.

  According to such a configuration, the steam generated in the exhaust heat recovery device flows upward due to a difference in specific gravity with water without staying in a region that can come into contact with the thermal expansion portion and the sealing body, and The water is discharged from the water inlet. Therefore, heat damage to the thermoactuator due to water vapor can be suppressed.

  One embodiment of the present disclosure may include a space capable of storing gas between the thermoactuator and the first water passage in the flow path of the cooling water. According to such a configuration, after the steam is retained in the space that does not contact the thermal expansion portion and the sealing body, the steam that overflows from this space can be discharged from the second water inlet. Therefore, heat damage to the thermoactuator due to water vapor can be more stably suppressed.

  In an aspect of the present disclosure, the heat exchange unit is provided between the thermoactuator and the first water passage in the flow path of the coolant, and the third water passage and the fourth water passage that allow the coolant to flow through the heat exchange unit. It may have a water opening. The fourth water passage may be arranged closer to the thermoactuator than the third water passage in the flow path of the cooling water, and may be located above the thermal expansion part and the sealing body. According to such a configuration, the height dimension of the exhaust heat recovery device can be reduced while suppressing heat damage to the thermoactuator due to water vapor.

  In an aspect of the present disclosure, the heat exchange unit is provided between the thermoactuator and the first water passage in the flow path of the coolant, and the third water passage and the fourth water passage that allow the coolant to flow through the heat exchange unit. It may have a water opening. The fourth water passage may be arranged closer to the thermoactuator than the third water passage in the flow path of the cooling water, and may be positioned above the third water passage. According to such a configuration, it is possible to increase the heat exchange efficiency in the exhaust heat recovery device while suppressing heat damage to the thermoactuator due to water vapor.

1A is a schematic front view of the exhaust heat recovery device according to the embodiment, and FIG. 1B is a schematic diagram illustrating a positional relationship between the storage space P and the uppermost portion T2 of the sealing body 43 in FIG. 1A. FIG. 2 is a schematic perspective view of the exhaust heat recovery device of FIG. 1A. FIG. 3 is a schematic sectional end view taken along line III-III in FIG. FIG. 4 is a schematic cutaway end view taken along line IV-IV in FIG. 2. 5A to 5G are schematic diagrams illustrating the positional relationship of each part in the exhaust heat recovery device different from FIG. 1A.

Hereinafter, embodiments to which the present disclosure is applied will be described with reference to the drawings.
[1. First Embodiment]
[1-1. Constitution]
The exhaust heat recovery device 1 shown in FIGS. 1A, 1B and 2 is provided in an exhaust gas flow path of an internal combustion engine and recovers heat of the exhaust gas into cooling water. The internal combustion engine provided with the exhaust heat recovery device 1 includes, for example, a gasoline engine or a diesel engine used for an automobile.

  The exhaust heat recovery unit 1 includes a heat exchange unit 2, a valve 3, a thermoactuator 4, a first water passage 5, a second water passage 6, a third water passage 7, a fourth water passage 8, A first pipe 10, a second pipe 11, and a third pipe 12 are provided.

<Water inlet>
The first water passage 5 is an inlet of the cooling water C in the exhaust heat recovery unit 1 in the present embodiment. The first water inlet 5 is provided at an end of the first pipe 10. The first water supply port 5 is connected to a hose for supplying cooling water.

  The second water inlet 6 is an outlet of the cooling water C in the exhaust heat recovery unit 1 in the present embodiment. The second water inlet 6 is provided at an end of the third pipe 12. A hose for discharging cooling water is connected to the second water inlet 6.

  The first water passage 5 and the second water passage 6 constitute both ends of the flow path of the cooling water C in the exhaust heat recovery device 1. That is, the upstream end of the flow path of the cooling water C in the exhaust heat recovery device 1 is the first water passage 5, and the downstream end is the second water passage 6. The cooling water C flows from the first water inlet 5 to the second water inlet 6.

  The third water passage 7 and the fourth water passage 8 are respectively provided between the thermoactuator 4 and the first water passage 5 in the flow path of the cooling water C. The third water passage 7 and the fourth water passage 8 allow cooling water to flow through the heat exchange unit 2.

  In the present embodiment, the third water passage 7 is a cooling water inlet to the heat exchange unit 2, and the fourth water passage 8 is a cooling water outlet from the heat exchange unit 2. Therefore, the fourth water passage 8 is disposed closer to the thermoactuator 4 than the third water passage 7 in the flow path of the cooling water C.

  The first pipe 10 is connected to the heat exchange unit 2 via the third water inlet 7, and the second pipe 11 is connected via the fourth water inlet 8. Therefore, the cooling water supplied from the first water passage 5 passes through the first pipe 10 and enters the heat exchange unit 2 from the third water passage 7. The cooling water that has entered the heat exchange section 2 passes through the second pipe 11 and the third pipe 12 from the fourth water inlet 8 and is discharged out of the system from the second water inlet 6.

<Heat exchange section>
The heat exchange unit 2 is a part that performs heat exchange between exhaust gas of the internal combustion engine and cooling water. The heat exchange unit 2 has a plurality of plates 21 as shown in FIG.

  The heat exchange unit 2 performs heat exchange between the exhaust gas flowing outside the plurality of plates 21 and cooling water flowing inside the plurality of plates 21 via the plates 21. Thereby, the heat exchange unit 2 gives the heat of the exhaust gas to the cooling water.

  The plurality of plates 21 are stacked in the flow direction of the exhaust gas G. Each plate 21 has a disk shape. However, the shape of each plate 21 is not limited to a disk shape, and may be another shape such as a rectangular shape with an open center. The cooling water supplied into each plate 21 from the third water passage 7 branches into two right and left ascending routes in each plate 21 and then gathers at the fourth water passage 8.

<Valve>
The valve 3 adjusts the amount of exhaust gas supplied to the heat exchange unit 2. The valve 3 is arranged between the exhaust gas inlet 13 and the exhaust gas outlet 14 in the exhaust heat recovery device 1 as shown in FIG.

  When the valve 3 is closed, the exhaust gas G introduced into the exhaust heat recovery unit 1 from the exhaust gas inlet 13 is supplied to the heat exchange unit 2 from the heat exchange unit inlet 15. The exhaust gas G cooled by the cooling water in the heat exchange unit 2 is discharged from the heat exchange unit outlet 16 to the outside of the heat exchange unit 2, and is discharged from the exhaust gas outlet 14. However, the heat exchange section 2 may be configured to discharge the exhaust gas G from the outside in the radial direction to the inside.

  On the other hand, when the valve 3 is open, part or all of the exhaust gas G introduced into the exhaust heat recovery device 1 from the exhaust gas inlet 13 passes through the bypass 17 and passes through the heat exchange unit 2. And is discharged from the exhaust gas outlet 14.

  The valve 3 is connected to the thermoactuator 4 via a cam 4A and a drive shaft 4B shown in FIG. The cam 4A is connected to the output section 44 of the thermoactuator 4 and the drive shaft 4B. However, the cam 4A and the drive shaft 4B are separated from each other in one of the state where the valve 3 is open and the state where the valve 3 is closed, and come into contact only in the other state. Good.

  The cam 4A is a member that converts a linear motion of the output unit 44 into a rotary motion of the drive shaft 4B. The drive shaft 4B is connected to the valve 3, and opens and closes the valve 3 by rotating its own shaft. That is, the valve 3 is switched between the open state and the closed state by the thermoactuator 4.

<Thermo actuator>
The thermoactuator 4 opens and closes the valve 3 according to the temperature of the cooling water. As shown in FIG. 4, the thermoactuator 4 has a thermal expansion section 41, a casing 42, a sealing body 43, an output section 44, and a spring 48.

  The thermal expansion section 41 is a rod-shaped member that expands and contracts by the heat of the cooling water. The thermal expansion section 41 has a thermal expansion body, a case that seals the thermal expansion body, and a pressure receiving member disposed in the case. As the thermal expansion body, for example, wax can be used. The pressure receiving member is a member that deforms as the thermal expansion body expands or contracts.

  The thermal expansion section 41 is arranged inside the casing 42. The thermal expansion section 41 has a dipping section 41A and a pressing section 41B. The immersion portion 41A is provided at one end in the axial direction of the thermal expansion portion 41, and the pressing portion 41B is provided at an axial end opposite to the immersion portion 41A.

  The immersion part 41A is immersed in cooling water supplied into the casing 42, and exchanges heat with the cooling water. The pressing portion 41B is disposed in the vicinity of the output portion 44, and presses the output portion 44 in the axial direction by extending in the axial direction due to thermal expansion.

  The casing 42 is a tubular member that houses the thermal expansion section 41. The casing 42 has a first opening 45 for introducing cooling water into the casing 42, a second opening 46 for discharging cooling water from the casing 42, and an internal space 47 for storing cooling water.

  In the present embodiment, the central axis L1 of the first opening 45 and the central axis L2 of the second opening 46 are arranged parallel to each other and at the same position in the axial direction of the thermal expansion section 41 when viewed from above. However, the central axis L1 of the first opening 45 may be offset from the central axis L2 of the second opening 46 in the axial direction of the thermal expansion portion 41. The central axis L1 of the first opening 45 and the central axis L2 of the second opening 46 do not have to be parallel.

  The first opening 45 and the second opening 46 communicate with an internal space 47. The second pipe 11 is connected to the first opening 45. The third pipe 12 is connected to the second opening 46. The immersion part 41A of the thermal expansion part 41 is arranged in the internal space 47.

  The sealing body 43 is a member that seals a space between the thermal expansion section 41 and the casing 42 and prevents leakage of cooling water from the thermoactuator 4 to the outside. As the sealing body 43, for example, a rubber O-ring can be used.

  The sealing body 43 is mounted on the outer peripheral surface of the thermal expansion section 41. Specifically, the sealing body 43 is disposed between the outer peripheral surface of the thermal expansion portion 41 and the inner peripheral surface of the casing 42 in a region between the immersion portion 41A and the pressing portion 41B of the thermal expansion portion 41. Have been.

  The output unit 44 is a rod-shaped member that opens and closes the valve 3 by expansion and contraction of the thermal expansion unit 41. Specifically, the output section 44 is arranged outside the pressing section 41B of the thermal expansion section 41 so that the central axes of the output section 44 and the thermal expansion section 41 are parallel to each other.

The output section 44 has a first end 44A close to the thermal expansion section 41, and a second end 44B opposite to the first end 44A.
The first end portion 44A contacts the pressing portion 41B when the thermal expansion portion 41 expands. The cam 4A shown in FIG. 2 is attached to the second end 44B.

  The spring 48 is a compression spring arranged so as to surround the output unit 44. The center axis of the spring 48 is parallel to the center axis of the output section 44. The spring 48 regulates a pressing force required to close the valve 3. Further, the spring 48 has a function of pushing the pressing portion 41B back toward the internal space 47 by an elastic force.

  When the thermal expansion section 41 expands, the output section 44 is pressed by the pressing section 41B and slides in the axial direction. When the output unit 44 slides, the cam 4A attached to the second end 44B rotates. The rotation of the cam 4A causes the valve 3 to open via the drive shaft 4B. Further, the spring 48 is compressed.

  On the other hand, when the thermal expansion portion 41 contracts, the pressing portion 41B retracts in the direction opposite to the direction in which the thermal expansion portion 41 expands, so that the pressing portion 41B does not press the output portion 44. Therefore, the valve 3 is closed by the restoring force of the compressed spring 48.

<Position of each part>
As shown in FIG. 1A, the first water inlet 5 is disposed below the thermoactuator 4. Further, the uppermost portion T1 of the inner surface of the third pipe 12 constituting the flow path of the cooling water C from the thermoactuator 4 to the second water inlet 6 is the uppermost portion of the thermal expansion portion 41 and the uppermost portion of the sealing body 43 of the thermoactuator 4. It is located above T2. Note that the uppermost portion T1 of the inner surface of the third pipe 12 is the uppermost portion of the inner surface of the wall 12A constituting the third pipe 12, and is the uppermost portion in the internal flow path of the third pipe 12. It is.

  In the present embodiment, the third pipe 12 is arranged so as to linearly extend upward from the thermoactuator 4. Although the uppermost portion T3 of the second water passage 6 is located above the uppermost portion T2 of the thermal expansion portion 41 and the sealing body 43, a part of the second water passage 6 is connected to the thermal expansion portion 41. And at the same height as the sealing body 43. That is, a part of the second water inlet 6 overlaps the thermal expansion part 41 and the sealing body 43 in the horizontal direction. In other words, the lowermost part T4 of the second water inlet 6 is located lower than the uppermost part T2 of the thermal expansion part 41 and the sealing body 43.

  The inclination angle θ (the acute angle) of the uppermost portion T1 of the inner surface of the third pipe 12 with respect to the horizontal direction is appropriately designed in consideration of the inclination of the vehicle on which the exhaust heat recovery device 1 is mounted. That is, when the inclination angle θ of the uppermost portion T1 is larger than the maximum inclination angle (for example, 7 ° or 8 °) when the exhaust heat recovery unit 1 is inclined in the direction in which the second water inlet 6 is displaced downward. Good.

  In the present embodiment, the fourth water passage 8 is located above the thermal expansion part 41 and the sealing body 43 of the thermoactuator 4. The second pipe 11 is disposed so as to extend linearly downward from the fourth water inlet 8 toward the thermoactuator 4. However, the second pipe 11 may be curved or bent in the middle.

  Therefore, as shown in FIG. 1B, a storage space P capable of storing gas (that is, water vapor) is formed on the fourth water inlet 8 side of the second pipe 11 (that is, on the upstream side in the flow path of the cooling water C). Have been. The storage space P is located above the thermal expansion part 41 of the thermoactuator 4 and the uppermost part T2 of the sealing body 43. Specifically, the storage space P is located above the lowest point α of the uppermost part T1 of the inner surface of the third pipe 12.

  When the internal combustion engine is stopped and the circulation of the cooling water is stopped, or when the flow rate of the cooling water is small, a part of the cooling water changes to steam. This steam gradually accumulates from above the heat exchange unit 2. That is, the water vapor accumulates in the storage space P. When the water vapor accumulates at a position where it reaches the uppermost portion T1 on the inner surface of the third pipe 12, the water vapor is discharged from the third pipe 12 to the outside. As described above, since the steam is discharged without contacting the thermal expansion section 41 and the sealing body 43, the thermal expansion section 41 and the sealing body 43 are hardly affected by the heat of the steam.

  In the present embodiment, the fourth water inlet 8 is located above the third water inlet 7. Therefore, the cooling water C supplied to the heat exchange unit 2 from the third water passage 7 exchanges heat with the exhaust gas while flowing upward in the heat exchange unit 2.

  In the present embodiment, the first pipe 10 is arranged so that its central axis is parallel to the horizontal direction. That is, the first water inlet 5 and the third water inlet 7 have the same center height. Further, the center of the third water inlet 7, the center of the fourth water inlet 8, and the center of the exhaust gas flow path (that is, the exhaust gas inlet 13 and the exhaust gas outlet 14 in FIG. 3) vertically overlap. Are located in However, these centers do not necessarily have to overlap in the vertical direction.

[1-2. effect]
According to the embodiment described in detail above, the following effects can be obtained.
(1a) The water vapor generated in the exhaust heat recovery device 1 flows upward due to a difference in specific gravity with water without staying in a region that can contact the thermal expansion portion 41 and the sealing body 43 of the thermoactuator 4, The water is discharged from the second water inlet 6 to the outside. Therefore, heat damage to the thermoactuator 4 due to water vapor can be suppressed.

  (1b) After the steam is retained in the storage space P that does not contact the thermal expansion section 41 and the sealing body 43, the steam overflowing from the storage space P can be discharged from the second water passage 6. Therefore, heat damage to the thermoactuator 4 due to water vapor can be suppressed more stably.

  (1c) Since the fourth water inlet 8 is located above the thermal expansion portion 41 and the sealing body 43, the height of the exhaust heat recovery unit 1 is reduced while suppressing heat damage to the thermoactuator 4 due to water vapor. Dimensions can be reduced.

  (1d) Since the fourth water inlet 8 is located above the third water inlet 7, it is possible to increase heat exchange efficiency in the exhaust heat recovery unit 1 while suppressing heat damage to the thermoactuator 4 due to steam. Can be.

[2. Other Embodiments]
As described above, the embodiments of the present disclosure have been described, but it is needless to say that the present disclosure is not limited to the above-described embodiments, and can take various forms.

  (2a) In the exhaust heat recovery unit 1 of the above embodiment, the third pipe 12 is curved or bent in the middle if the uppermost part T1 of the inner surface is located above the thermal expansion part 41 and the sealing body 43. You may.

  (2b) In the exhaust heat recovery unit 1 of the above embodiment, the cooling water C may flow from the second water passage 6 toward the first water passage 5. In this case, the cooling water C is supplied from the fourth water passage 8 to the heat exchange unit 2, and the cooling water C is discharged from the heat exchange unit 2 to the third water passage 7.

  (2c) In the exhaust heat recovery unit 1 of the above embodiment, the positional relationship between the third water inlet 7 and the fourth water inlet 8 is an example. In the exhaust heat recovery device 1, for example, a third water passage 7 and a fourth water passage 8 may be arranged as follows.

  In the exhaust heat recovery unit 1A shown in FIG. 5A, the fourth water passage 8 has the same height as the thermal expansion part and the sealing body of the thermoactuator 4 (that is, a position overlapping the thermal expansion part and the sealing body in the horizontal direction). It is provided in.

  In the exhaust heat recovery unit 1B shown in FIG. 5B, the third water passage 7 and the fourth water passage 8 are provided at the same height. In the heat exchange section 2A of FIG. 5B, the cooling water C flows in the horizontal direction. In the exhaust heat recovery unit 1B, the third water inlet 7 is also located above the thermal expansion part of the thermoactuator 4 and the sealing body.

  The exhaust heat recovery device 1C shown in FIG. 5C is different from the exhaust heat recovery device 1B in FIG. 5B in that the third water passage 7 and the fourth water passage 8 are provided at the same height as the thermal expansion part and the sealing body of the thermoactuator 4. It was done.

  In the exhaust heat recovery device 1D shown in FIG. 5D, the fourth water passage 8 is provided at a position lower than the thermal expansion part of the thermoactuator 4 and the sealing body. In the exhaust heat recovery device 1D, the second pipe 11 has a bent portion 11A located above the thermal expansion portion of the thermoactuator 4 and the sealing body. Therefore, a storage space capable of storing gas is formed in the bent portion 11A. In the exhaust heat recovery device 1D, the third water passage 7 and the fourth water passage 8 are provided at the same height.

  In the exhaust heat recovery device 1E shown in FIG. 5E, in the exhaust heat recovery device 1D in FIG. 5D, the bent portion 11A in the second pipe 11 is provided at the same height as the thermal expansion portion and the sealing body of the thermoactuator 4. Things.

An exhaust heat recovery device 1F shown in FIG. 5F is the same as the exhaust heat recovery device 1D of FIG. 5D, except that the third water inlet 7 is provided below the fourth water inlet 8.
An exhaust heat recovery device 1G shown in FIG. 5G is the same as the exhaust heat recovery device 1E in FIG. 5E, except that the third water inlet 7 is provided below the fourth water inlet 8.

  (2d) The functions of one component in the above embodiment may be distributed as a plurality of components, or the functions of a plurality of components may be integrated into one component. Further, a part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above-described embodiment may be added to or replaced with the configuration of another above-described embodiment. Note that all aspects included in the technical idea specified by the language described in the claims are embodiments of the present disclosure.

1,1A, 1B, 1C, 1D, 1E, 1F, 1G ... Exhaust heat recovery unit,
2, 2A: heat exchange part, 3: valve, 4: thermo actuator, 4A: cam,
4B: drive shaft, 5: first water hole, 6: second water hole, 7: third water hole, 8: fourth water hole,
Reference numeral 10: first pipe, 11: second pipe, 11A: bent portion, 12: third pipe, 12A: wall,
13 ... exhaust gas inlet, 14 ... exhaust gas outlet, 15 ... heat exchange section inlet,
16: heat exchange section outlet, 17: bypass passage, 21: plate, 41: thermal expansion section,
41A: dipping section, 41B: pressing section, 42: casing, 43: sealing body, 44: output section,
44A: first end, 44B: second end, 45: first opening, 46: second opening,
47 ... internal space, 48 ... spring.

Claims (4)

A heat exchange unit that performs heat exchange between exhaust gas of the internal combustion engine and cooling water,
A valve for adjusting a supply amount of the exhaust gas to the heat exchange unit,
A thermal expansion portion that expands and contracts by the heat of the cooling water, a casing that houses the thermal expansion portion, a sealing body that seals between the thermal expansion portion and the casing, and opens and closes the valve by expansion and contraction of the thermal expansion portion A thermoactuator having an output unit for causing
A first water port and a second water port forming both ends of the cooling water flow path,
An exhaust heat recovery device comprising:
The first water port is disposed below the thermoactuator,
An exhaust heat recovery device, wherein an uppermost part of an inner surface of a pipe constituting a flow path of the cooling water from the thermoactuator to the second water inlet is located above the thermal expansion part and the sealing body. The exhaust heat recovery device according to claim 1,
An exhaust heat recovery device, comprising: a space capable of storing gas between the thermoactuator and the first water passage in the flow path of the cooling water. The exhaust heat recovery device according to claim 2, wherein
The heat exchange unit is provided between the thermoactuator and the first water passage in the flow path of the cooling water, and has a third water passage and a fourth water passage through which the cooling water flows through the heat exchange unit. Have
The fourth water passage is disposed closer to the thermoactuator than the third water passage in the flow path of the cooling water, and is located above the thermal expansion portion and the sealing body. Collection device. The exhaust heat recovery device according to any one of claims 1 to 3, wherein
The heat exchange unit is provided between the thermoactuator and the first water passage in the flow path of the cooling water, and has a third water passage and a fourth water passage through which the cooling water flows through the heat exchange unit. Have
The exhaust heat recovery device, wherein the fourth water passage is disposed closer to the thermoactuator than the third water passage in the flow path of the cooling water, and is located above the third water passage.

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