Exhaust heat recovery device

Abstract

An exhaust heat recovery device (10) comprises: a first exhaust pipe (22); a second exhaust pipe (24); a third exhaust pipe (26); a heat recovery material (80); a medium flow path (132); a valve (161); and an actuator (169) that is disposed radially outward of the third exhaust pipe (26) and that opens and closes the valve (161). The medium flow path (132) has a bulging portion (50) that is formed to bulge outward in the radial direction of the medium flow path (132), and has an inlet portion (145) to which a medium inlet pipe (151) opening toward an exhaust gas flow direction of the third exhaust pipe (26) is connected, and an outlet portion (146) to which a medium outlet pipe (152) opening toward the exhaust gas flow direction of the third exhaust pipe (26) is connected. The bulging portion (50) is disposed so as to bulge to the same circumferential position as the circumferential position at which the actuator (169) is disposed when viewed from the exhaust gas flow direction of the third exhaust pipe (26).

Description

Exhaust heat recovery device

[0001] The present invention relates to an exhaust heat recovery device.

[0002] JP2020-506328A discloses an exhaust heat recovery device including a heat exchanger, a bypass conduit, and a valve for adjusting the amount of gas circulating through each of the heat exchanger and the bypass conduit.

[0003] In the configuration described in JP2020-506328A, the heat exchanger and the bypass pipe are arranged in parallel in the flow direction of the exhaust gas, which increases the size of the exhaust heat recovery device, making it difficult to reduce its size.

[0004] An object of the present invention is to reduce the size of an exhaust heat recovery device without reducing the heat recovery efficiency.

[0005] According to one aspect of the present invention, an exhaust heat recovery device includes: a first exhaust pipe; a second exhaust pipe into which a downstream end of the first exhaust pipe is inserted, forming a gap between the second exhaust pipe and an outer periphery of the first exhaust pipe and allowing exhaust gas to flow; a third exhaust pipe arranged to surround the downstream end of the first exhaust pipe and the second exhaust pipe; an annular heat recovery material arranged between the second exhaust pipe and the third exhaust pipe, through which exhaust gas passes; a medium flow path arranged to surround the third exhaust pipe, performing heat exchange between an inflowing medium and the heat recovery material; a valve arranged downstream of the portion of the second exhaust pipe into which the first exhaust pipe is inserted, for opening and closing the second exhaust pipe, and in a closed state, for directing exhaust gas through the gap to the heat recovery material and for directing exhaust gas to the third exhaust pipe, bypassing the heat recovery material, and an actuator arranged radially outward of the third exhaust pipe for opening and closing the valve. The medium flow path has a bulging portion that is formed by bulging radially outward from the medium flow path and has an inlet portion to which a medium inlet pipe that opens toward the exhaust gas flow direction of the third exhaust pipe is connected, and an outlet portion to which a medium outlet pipe that opens toward the exhaust gas flow direction of the third exhaust pipe is connected, and when viewed from the exhaust gas flow direction, the bulging portion is positioned so as to bulge at the same circumferential position as the circumferential position at which the actuator is positioned.

[0006] In the above-described embodiment, the bulging portion, to which the medium inlet pipe and medium outlet pipe that allow the medium to flow through the medium flow path are connected, is located at the same circumferential position as the actuator that opens and closes the valve, so that the radially outward expansion of the exhaust heat recovery device can be minimized, thereby enabling the size of the exhaust heat recovery device to be reduced without reducing heat recovery efficiency.

[0007] Fig. 1 is a perspective view of an exhaust heat recovery device according to an embodiment of the present invention. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. Fig. 3 is a front view of the exhaust heat recovery device. Fig. 4 is a side view of the exhaust heat recovery device. Fig. 5 is an exploded perspective view of a cooling water flow path of the exhaust heat recovery device. Fig. 6 is a perspective view of a partition wall in a bulging portion. Fig. 7 is a cross-sectional view of the exhaust heat recovery device when the valve is in an open state. Fig. 8 is a cross-sectional view of the exhaust heat recovery device when the valve is in a closed state.

[0008] Hereinafter, an exhaust heat recovery device 10 according to an embodiment of the present invention will be described with reference to the drawings.

[0009] FIG. 1 is a perspective view of the exhaust heat recovery device 10, and FIG. 2 is a cross-sectional view taken along line II-II of FIG.

[0010] The exhaust heat recovery device 10 is provided in an exhaust path of an engine (not shown) of, for example, an automobile (not shown), and recovers heat from exhaust gas 20 emitted from the engine. The exhaust heat recovery device 10 uses the recovered heat to warm up engine coolant, for example, before the engine is warmed up.

[0011] As shown in FIG. 1 , the exhaust heat recovery device 10 includes a gas flow section 12 , a heat recovery section 14 , and a switching mechanism section 16 .

[0012] 2, the gas flow section 12 includes a first exhaust pipe 22, a second exhaust pipe 24, and a third exhaust pipe 26. Exhaust gas 20 flows through the gas flow section 12.

[0013] Each of the exhaust pipes 22, 24, and 26 is made of, for example, a metal pipe formed into a substantially cylindrical shape. Stainless steel is an example of the metal that makes up each of the exhaust pipes 22, 24, and 26. The exhaust pipes 22, 24, and 26 are arranged coaxially so that their respective central axes 28 coincide with each other.

[0014] The first exhaust pipe 22 allows exhaust gas 20 to flow from the upstream side to the downstream side. An upper end of the first exhaust pipe 22 is connected to an exhaust pipe (not shown). Exhaust gas 20 from the engine is sent to the first exhaust pipe 22. The first exhaust pipe 22 has a first large diameter section 30 connected to the upstream exhaust pipe (not shown), a first tapered section 32 extending from the first large diameter section 30 and decreasing in diameter toward the downstream side in the flow direction of the exhaust gas 20, and a first small diameter section 34 extending from the first tapered section 32 toward the downstream side in the flow direction.

[0015] The second exhaust pipe 24 is supplied with the exhaust gas 20 that has passed through the first exhaust pipe 22. The downstream end of the first exhaust pipe 22 is inserted into the second exhaust pipe 24, and an annular passage 46 is formed between the second exhaust pipe 24 and the outer periphery of the first exhaust pipe 22, as a gap through which the exhaust gas 20 can flow. The second exhaust pipe 24 has a second large diameter section 40, which is an upstream end, that is disposed so as to surround the first small diameter section 34, which is the downstream end of the first exhaust pipe 22. The second exhaust pipe 24 also has a second tapered section 42 that extends from the second large diameter section 40 and whose diameter decreases toward the downstream side in the flow direction, and a second small diameter section 44 that extends from the second tapered section 42 to the downstream side in the flow direction.

[0016] The inner diameter dimension of the second large diameter portion 40 of the second exhaust pipe 24 is larger than the outer diameter dimension of the first small diameter portion 34 of the first exhaust pipe 22. As a result, an annular passage 46 is formed between the outer periphery of the first small diameter portion 34 of the first exhaust pipe 22 and the inner periphery of the second large diameter portion 40 of the second exhaust pipe 24.

[0017] A welded portion 44a of the second small diameter portion 44, which is to be welded to a bearing member 163 (described later), is formed flat, and the other portion of the second small diameter portion 44 is formed cylindrical. As a result, the flow path cross section on the inner periphery of the second small diameter portion 44 is formed into a substantially D-shape by the flat welded portion 44a and the other cylindrical portion. A valve 161 (described later) that switches the flow of exhaust gas 20 flowing through the second exhaust pipe 24 is provided inside the second small diameter portion 44 of the second exhaust pipe 24.

[0018] The third exhaust pipe 26 is disposed so as to surround the downstream end of the first exhaust pipe 22 and the second exhaust pipe 24. Specifically, the third exhaust pipe 26 surrounds the outer periphery of the first exhaust pipe 22 from a downstream portion of the first large diameter section 30 to the first small diameter section 34, and the entire second exhaust pipe 24. The third exhaust pipe 26 has a third large diameter section 60 disposed on the outer periphery of the second exhaust pipe 24, a third tapered section 62 extending from the third large diameter section 60 and decreasing in diameter toward the downstream side in the flow direction, and a third small diameter section 64 extending from the third tapered section 62 toward the downstream side in the flow direction. The upstream portion of the third large diameter section 60 in the flow direction is configured by a cylindrical member 66, which is a separate member.

[0019] The inner diameter dimension of the third large diameter portion 60 of the third exhaust pipe 26 is larger than the outer diameter dimension of the second large diameter portion 40 of the second exhaust pipe 24, and an annular gap is formed between the second large diameter portion 40 of the second exhaust pipe 24 and the third large diameter portion 60 of the third exhaust pipe 26. As a result, a bypass flow path 68 is formed around the outer periphery of the second large diameter portion 40 of the second exhaust pipe 24, through which the exhaust gas 20 that has passed through the annular passage 46 flows.

[0020] The third exhaust pipe 26 has a flange portion 61 that protrudes radially outward from the outer periphery of the third large diameter portion 60 of the third exhaust pipe 26. The flange portion 61 is provided on the outer periphery of a hole that penetrates the third exhaust pipe 26 in the radial direction and into which a bearing member 163, which will be described later, is inserted. The flange portion 61 is formed in a substantially cylindrical shape with an inner circumferential surface that abuts against the outer circumferential surface of the bearing member 163.

[0021] A collar 70 is disposed around the entire circumference between the end of the third large diameter portion 60 of the third exhaust pipe 26 and the first large diameter portion 30 of the first exhaust pipe 22 .

[0022] The collar 70 has an inner circumferential wall 72 and an outer circumferential wall 74, and is formed with a generally U-shaped cross section. The collar 70 is fixed to the first large diameter portion 30 of the first exhaust pipe 22 with the inner circumferential wall 72 in close contact with the first large diameter portion 30. The collar 70 is also fixed to the third large diameter portion 60 of the third exhaust pipe 26 with the outer circumferential wall 74 in close contact with the third large diameter portion 60. As a result, the end of the bypass flow path 68 is closed by the collar 70.

[0023] An annular heat recovery material 80 is arranged between the second large diameter portion 40 of the second exhaust pipe 24 and the third large diameter portion 60 of the third exhaust pipe 26. The exhaust gas 20 passes through the heat recovery material 80, and heat is exchanged between the heat recovery material 80 and coolant, which serves as a medium, flowing through a medium flow path 132 (described below) that is provided on the outer periphery of the third exhaust pipe 26. The heat recovery material 80 is formed in an annular shape surrounding the second exhaust pipe 24, and recovers heat from the exhaust gas 20 flowing through the bypass flow path 68.

[0024] The heat recovery material 80 is formed of, for example, a material whose main component is ceramic. The thermal expansion coefficient of the ceramic-based heat recovery material 80 differs from the thermal expansion coefficient of each of the metal exhaust pipes 22, 24, 26. The heat recovery material 80 is made of a honeycomb structure. Specifically, the heat recovery material 80 includes a cylindrical inner tube portion 84 that forms the inner circumferential surface, a cylindrical outer tube portion 88 that forms the outer circumferential surface, and a honeycomb portion 90 that is arranged between the inner tube portion 84 and the outer tube portion 88.

[0025] The honeycomb portion 90 is made of a honeycomb-shaped core material. Each of the vertical and horizontal walls constituting the honeycomb portion 90 extends in the flow direction of the exhaust gas 20 flowing through the bypass flow path 68. As a result, the honeycomb portion 90 has a plurality of passages penetrating in the flow direction, and recovers heat from the exhaust gas 20 passing through each passage while allowing the exhaust gas 20 to flow.

[0026] A gasket 100 serving as a pressing member is disposed between the heat recovery material 80 and the second large diameter portion 40 of the second exhaust pipe 24 .

[0027] The gasket 100 is formed of a cylindrical plate-like member. The plate-like member that constitutes the gasket 100 is made of, for example, a metal plate. The gasket 100 is formed to a size that allows it to fit onto the second large diameter portion 40 of the second exhaust pipe 24.

[0028] The gasket 100 is provided between the second exhaust pipe 24 and the heat recovery material 80 and presses them against each other in the radial direction. Specifically, the gasket 100 is fitted, for example, in a diameter-reduced state onto the inner circumferential surface of the inner cylindrical portion 84 of the heat recovery material 80, and then fixed by expanding the diameter of the second large diameter portion 40 of the second exhaust pipe 24. In this way, the gasket 100 is disposed in a state inserted between the second large diameter portion 40 of the second exhaust pipe 24 and the heat recovery material 80.

[0029] The gasket 100 is capable of elastic deformation in the radial direction when it is disposed between the second large diameter portion 40 of the second exhaust pipe 24 and the heat recovery material 80. When it is attached, the gasket 100 presses the heat recovery material 80 so that the outer peripheral surface of the outer tubular portion 88 is in close contact with the inner peripheral surface of the third exhaust pipe 26. The heat recovered by the heat recovery material 80 is transferred to the cylindrical member 66 that constitutes the third large diameter portion 60 of the third exhaust pipe 26.

[0030] The gasket 100 is provided so as to be slidable relative to the second exhaust pipe 24 in the longitudinal direction of the second exhaust pipe 24 (the direction along the central axis 28). As a result, the gasket 100 allows relative thermal deformation between the second exhaust pipe 24 and the heat recovery material 80 in the longitudinal direction of the second exhaust pipe 24. Specific functions will be described in detail in the explanation of functions and effects.

[0031] Next, the configuration of the heat recovery section 14 will be described with reference to Figures 3 to 6. Figure 3 is a front view of the exhaust heat recovery machine, and Figure 4 is a side view of the exhaust heat recovery machine. Figure 5 is an exploded perspective view of the heat recovery section 14, and Figure 6 is a perspective view of the bulging portion 50 of the heat recovery section 14.

[0032] The heat recovery unit 14 heats the cooling water by utilizing the heat of the exhaust gas 20. The heat recovery unit 14 has a first cover member 130, a second cover member 140, a medium inlet pipe 151, and a medium outlet pipe 152.

[0033] 2, the first cover member 130 and the second cover member 140 are arranged to surround the outer periphery of the cylindrical member 66 that surrounds the heat recovery material 80. By circulating cooling water within the space surrounded by the first cover member 130 and the second cover member 140, heat exchange occurs between the heat recovery material 80 and the cooling water.

[0034] The first cover member 130 has an approximately cylindrical shape and is the outer periphery of the cylindrical member 66 that constitutes the third large diameter section 60 of the third exhaust pipe 26, and is configured in a shape that surrounds the entire circumference of the cylindrical member 66 from near the collar 70 to near the upstream side in the flow direction of the heat recovery material 80.

[0035] The second cover member 140 has a substantially cylindrical shape and is the outer periphery of the cylindrical member 66 that constitutes the third large diameter section 60 of the third exhaust pipe 26, and is configured in a shape that surrounds the entire circumference of the cylindrical member 66 from near the upstream end to near the downstream end of the heat recovery material 80. A portion of the second cover member 140 contacts the entire outer periphery of the first cover member 130 on the upstream side in the flow direction.

[0036] In this way, the heat recovery section 14 forms a space surrounded by the first cover member 130 , the second cover member 140 and the cylindrical member 66 , and this space is configured as a medium flow path 132 .

[0037] The heat recovery section 14 is formed as a bulging portion 50, a portion of which bulges outward (here, upward) from the outside periphery. Specifically, as shown in FIGS. 3 and 4 , the first cover member 130 stands vertically upward in a rectangular or trapezoidal shape, and the second cover member 140 connected to the first cover member 130 also has a similar shape. The bulging portion 50 is configured to bulge out from the gas flow section 12 at the same circumferential position as the switching mechanism 16 (including the actuator 169 and the spindle 162) that is disposed above the gas flow section 12. That is, the bulging portion 50 is disposed so as to bulge out at a position that overlaps with the switching mechanism 16 when viewed from the gas flow direction.

[0038] The switching mechanism 16 is an essential component for switching the valve 161 and is disposed on the outer circumferential side of the gas flow unit 12. Therefore, the bulging portion 50, which is configured to connect the medium inlet pipe 151 and the medium outlet pipe 152 that allow cooling water to flow in and out of the medium flow path 132, is disposed at the same circumferential position as the switching mechanism 16. Furthermore, the spindle 162, which is the rotation axis of the switching mechanism 16, is disposed between the medium inlet pipe 151 and the medium outlet pipe 152 when viewed from the gas flow direction. Furthermore, as shown in FIG. 3 , the circumferential protrusion height of the bulging portion 50 is configured to be smaller than the protrusion height of the switching mechanism 16.

[0039] As a result, even if the bulge portion 50 is arranged on the outer periphery of the gas flow section 12, the exhaust heat recovery device 10 does not expand circumferentially, so the exhaust heat recovery device 10 can be made smaller without reducing the efficiency of heat recovery by the heat recovery section 14.

[0040] In the bulging portion 50, the side of the first cover member 130 facing the upstream direction is configured as a flat portion 130a. The second cover member 140 is configured as an inclined portion 140a having a gentle inclined surface facing the downstream side from the flat portion 130a.

[0041] As shown in Figure 5, the planar portion 130a of the first cover member 130 has an inlet portion 145 that introduces the medium into the medium flow path 132 and an outlet portion 146 through which the medium flows out of the medium flow path 132. The inlet portion 145 and the outlet portion 146 are configured to protrude cylindrically from the planar portion toward the upstream side of the exhaust flow. A medium inlet pipe 151 is connected to the inlet portion 145, and another medium inlet pipe 152 is connected to the inlet portion 145. The medium inlet pipe 151 supplies cooling water to the medium flow path 132. The medium outlet pipe 152 recovers the cooling water in the medium flow path 132.

[0042] These inlet portion 145 and outlet portion 146 are configured as burred portions that are processed into a protruding shape by burring on the flat portion 130a of the first cover member 130. With this configuration, it is possible to simultaneously drill holes and form the protruding shape, thereby reducing the number of processing steps.

[0043] As shown in FIG. 6 , a partition wall 49 is disposed in the internal space of the bulging portion 50. The partition wall 49 is a thin plate-like member disposed to separate the inlet portion 145 and the outlet portion 146, and is disposed between the inlet portion 145 and the outlet portion 146, from the flat portion 130 a to the inclined portion 140 a. The partition wall 49 is provided to prevent the cooling water flowing in from the inlet portion 145 from immediately bypassing and flowing out to the outlet portion 146. By disposing the partition wall 49 between the inlet portion 145 and the outlet portion 146, the cooling water flowing in from the inlet portion 145 is encouraged to flow counterclockwise within the medium flow path 132. This allows the cooling water to flow around the heat recovery material 80, thereby facilitating heat recovery.

[0044] The heat of the exhaust gas 20 recovered by the heat recovery material 80 is transferred to the cooling water flowing through the medium flow path 132 via the cylindrical member 66 of the third exhaust pipe 26. This forms the heat recovery section 14 that warms the cooling water by utilizing the heat of the exhaust gas 20.

[0045] Next, the switching mechanism 16 will be described. As shown in Fig. 2, the switching mechanism 16 has a valve 161, a spindle 162 as a rotation shaft, a bearing member 163 for the valve 161, a seal member 164, an actuator 169, and a fixing member 170. The switching mechanism 16 switches the flow of the exhaust gas 20 in the gas flow section 12.

[0046] The valve 161 is formed in a circular, flat plate shape to correspond to the flow path cross section of the second small diameter portion 44 of the second exhaust pipe 24. The valve 161 is rotatably supported by a spindle 162. The valve 161 opens and closes the communication passage 48, which communicates with the third exhaust pipe 26 from the second exhaust pipe 24 without passing through the annular passage 46, downstream of the portion of the second exhaust pipe 24 where the first exhaust pipe 22 is inserted.

[0047] In an open state (the state shown in FIG. 2 ) where the surface of the valve 161 is oriented along the flow direction, the valve 161 allows the exhaust gas 20 from the first exhaust pipe 22 to flow downstream of the second exhaust pipe 24. In a closed state (the state shown in FIG. 8 ) where the surface of the valve 161 is oriented perpendicular to the flow direction, the valve 161 inhibits the flow of the exhaust gas 20 downstream of the second exhaust pipe 24 and promotes the flow of the exhaust gas 20 toward the annular passage 46.

[0048] That is, when the communication passage 48 is closed, the valve 161 causes the exhaust gas 20 to flow through the annular passage 46 and be guided to the heat recovery material 80, and when the communication passage 48 is open, the valve 161 causes the exhaust gas 20 to flow so as to bypass the heat recovery material 80. The switching of the flow of the exhaust gas 20 will be described in detail in the explanation of the operation and effects.

[0049] 2, the spindle 162 is formed in a substantially cylindrical shape. The spindle 162 is provided to penetrate from the outside of the third exhaust pipe 26 to the inside of the second exhaust pipe 24. A valve 161 is provided at one end of the spindle 162. The other end of the spindle 162 is attached to an actuator 169. The rotation of the spindle 162 is controlled by the actuator 169.

[0050] The bearing member 163 is formed in a tubular shape (here, approximately cylindrical). The bearing member 163 is provided between the second exhaust pipe 24 and the third exhaust pipe 26, and extends through the third exhaust pipe 26 to the outside. The bearing member 163 connects and fixes the second exhaust pipe 24 and the third exhaust pipe 26. The bearing member 163 has a seal member 164 that seals between the spindle 162 of the valve 161 and the second exhaust pipe 24.

[0051] The actuator 169 is driven by power supplied from a power supply (not shown) and controlled by an electric signal from a controller (not shown). The actuator 169 drives the spindle 162 to rotate.

[0052] The actuator 169 is supported by a fixed member 170, which is a cup-shaped metal member. The fixed member 170 is attached to the outer surfaces of the second cover member 140 and the third large diameter portion 60 at multiple locations by multiple brackets 171 (see FIG. 1).

[0053] Next, the operation of the exhaust heat recovery device 10 will be described with reference to Figures 7 and 8. Figure 7 is a cross-sectional view of the exhaust heat recovery device 10 illustrating the flow of the exhaust gas 20 when the valve 161 is open. Figure 8 is a cross-sectional view of the exhaust heat recovery device 10 illustrating the flow of the exhaust gas 20 when the valve 161 is closed.

[0054] First, with reference to FIG. 7, a case where the valve 161 is in an open state and the heat of the exhaust gas 20 is not recovered by the cooling water flowing through the heat recovery section 14 will be described.

[0055] 7, exhaust gas 20 emitted from the engine flows into a first exhaust pipe 22 via an upstream exhaust pipe (not shown). The exhaust gas 20 that flows into the exhaust heat recovery device 10 from the first exhaust pipe 22 continues straight ahead and is guided into a second exhaust pipe 24.

[0056] At this time, the valve 161 is in an open state and the communication passage 48 is open, so the exhaust gas 20 that has flowed into the second exhaust pipe 24 passes through the communication passage 48 and is guided into the third exhaust pipe 26, and then flows out into a downstream exhaust pipe (not shown). In other words, the exhaust gas 20 flows through the exhaust heat recovery device 10 so as to bypass the heat recovery material 80.

[0057] Therefore, the exhaust gas 20 is not guided to the heat recovery material 80 , and the heat of the exhaust gas 20 is not recovered by the cooling water flowing through the heat recovery section 14 .

[0058] From this state, when the actuator 169 rotates the spindle 162 to close the valve 161, the valve 161 enters the closed state as shown in FIG.

[0059] Next, with reference to FIG. 8, a case where the valve 161 is in a closed state and the heat of the exhaust gas 20 is recovered by the cooling water flowing through the heat recovery section 14 will be described.

[0060] As shown in Figure 8, exhaust gas 20 emitted from the engine flows into the first exhaust pipe 22 via an upstream exhaust pipe (not shown). The exhaust gas 20 that flows from the first exhaust pipe 22 into the exhaust heat recovery device 10 travels straight ahead and is guided into the second exhaust pipe 24. At this time, because the valve 161 is closed and the communication passage 48 is closed, the exhaust gas 20 that flows into the second exhaust pipe 24 passes through the annular passage 46 and is guided to the bypass passage 68. The exhaust gas 20 guided to the bypass passage 68 passes through the heat recovery material 80, so that heat is transferred to the cooling water flowing around the heat recovery section 14. The exhaust gas 20 is then guided from the bypass passage 68 into the third exhaust pipe 26 and flows out into a downstream exhaust pipe (not shown).

[0061] Therefore, the exhaust gas 20 is guided to the heat recovery material 80 , and the heat of the exhaust gas 20 is recovered by the cooling water flowing through the heat recovery section 14 .

[0062] According to the above embodiment, the following effects are achieved.

[0063] The exhaust heat recovery device 10 includes a first exhaust pipe 22, a second exhaust pipe 24 into which the downstream end of the first exhaust pipe 22 is inserted and which forms a gap between the second exhaust pipe 24 and the outer periphery of the first exhaust pipe 22 and allows the exhaust gas 20 to flow, a third exhaust pipe 26 which is arranged to surround the downstream end of the first exhaust pipe 22 and the second exhaust pipe 24, an annular heat recovery material 80 which is arranged between the second exhaust pipe 24 and the third exhaust pipe 26 and through which the exhaust gas 20 passes, and a heat recovery material 80 which is arranged to surround the third exhaust pipe 26 and which recovers the heat from the inflowing medium. The exhaust pipe 26 includes a medium flow path 132 for exchanging heat with the recovery material 80, a valve 161 that opens and closes the second exhaust pipe 24 downstream of the portion of the second exhaust pipe 24 where the first exhaust pipe 22 is inserted, and in a closed state, causes the exhaust gas 20 to pass through the gap and be guided to the heat recovery material 80, and in an open state, causes the exhaust gas 20 to bypass the heat recovery material 80 and be guided to the third exhaust pipe 26, and an actuator 169 that is arranged radially outside the third exhaust pipe 26 and opens and closes the valve 161. The medium flow path 132 has a bulging portion 50 that is formed by bulging radially outward from the medium flow path 132, and has an inlet portion 145 to which a medium inlet pipe 151 that opens toward the exhaust gas flow direction of the third exhaust pipe 26 is connected, and an outlet portion 146 to which a medium outlet pipe 152 that opens toward the exhaust gas flow direction of the third exhaust pipe 26 is connected, and when viewed from the exhaust gas flow direction of the third exhaust pipe 26, the bulging portion 50 is arranged to bulge at the same circumferential position as the circumferential position at which the actuator 169 is arranged.

[0064] In this configuration, the bulging portion 50, to which the medium inlet pipe 151 and medium outlet pipe 152 that allow the medium to flow through the medium flow path 132 are connected, is disposed at the same circumferential position as the actuator 169 that opens and closes the valve 161, thereby minimizing the radially outward expansion of the exhaust heat recovery device 10. This makes it possible to reduce the size of the exhaust heat recovery device 10 without reducing the heat recovery efficiency.

[0065] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0066] For example, although the exhaust heat recovery device 10 according to the above embodiment has been described as using recovered heat to warm the cooling water, the embodiments are not limited to this. Other media may be circulated instead of the cooling water, and the recovered heat may be configured to warm gear oil or the like.

[0067] Furthermore, in the above embodiment, the exhaust heat recovery device 10 is described as being applied to an automobile, but the above embodiment is not limited to this, and the exhaust heat recovery device 10 may also be applied to engines, heat-generating devices, etc. other than vehicles.

[0068] This application claims priority from Japanese Patent Application No. 2024-093084, filed with the Japan Patent Office on June 7, 2024, the entire contents of which are incorporated herein by reference.

Claims

1. An exhaust heat recovery device comprising: a first exhaust pipe; a second exhaust pipe into which the downstream end of the first exhaust pipe is inserted, forming a gap between the second exhaust pipe and the outer periphery of the first exhaust pipe and allowing exhaust gas to flow; a third exhaust pipe arranged to surround the downstream end of the first exhaust pipe and the second exhaust pipe; an annular heat recovery material arranged between the second exhaust pipe and the third exhaust pipe, and through which the exhaust gas passes; a medium flow path arranged to surround the third exhaust pipe, and performing heat exchange between an inflowing medium and the heat recovery material; a valve arranged on the second exhaust pipe downstream of the portion into which the first exhaust pipe is inserted, for opening and closing the second exhaust pipe, such that, in a closed state, the exhaust gas passes through the gap and is guided to the heat recovery material, and, in an open state, the exhaust gas bypasses the heat recovery material and is guided to the third exhaust pipe; and an actuator arranged radially outward of the third exhaust pipe, for opening and closing the valve. an exhaust heat recovery device in which the medium flow path has a bulging portion formed by bulging radially outward from the medium flow path, and has an inlet portion to which a medium inlet pipe that opens toward the exhaust gas flow direction of the third exhaust pipe is connected, and an outlet portion to which a medium outlet pipe that opens toward the exhaust gas flow direction of the third exhaust pipe is connected, and the bulging portion is arranged to bulge at the same circumferential position as the circumferential position at which the actuator is arranged when viewed from the exhaust gas flow direction of the third exhaust pipe.

2. An exhaust heat recovery device according to claim 1, wherein the inlet section and the outlet section have burred sections in the bulging section that are burred so as to protrude in the direction of exhaust gas flow in the third exhaust pipe.

3. An exhaust heat recovery device according to claim 1, wherein the bulging portion is provided with a partition wall on the inside thereof between the inlet portion and the outlet portion, which prevents the medium that has flowed in from the inlet portion from bypassing to the outlet portion.

4. An exhaust heat recovery device as claimed in claim 1, wherein the actuator has a rotary shaft that rotates the valve, and the rotary shaft is arranged between the inlet and outlet of the bulging portion in the exhaust gas flow direction of the third exhaust pipe.

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