JP2015158192A - Exhaust heat recovery device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust heat recovery device which enables free layout design of a pipeline in which a medium flows.SOLUTION: An exhaust heat recovery device includes: a first passage 4 in which an exhaust gas passes through a heat exchanger 3 for conducting heat exchange between an exhaust gas and a medium; a second passage 5 in which the exhaust gas detours the heat exchanger 3; a valve body 30 which opens and closes the second passage 5; and a thermoelement 36 which opens the valve body 30 when a temperature of the medium becomes equal to or higher than a predetermined value. The thermoelement 36 has a heat receiving part 36a. A communication passage 32 which allows the interior of a medium passage 3a, in which the medium circulates in the heat exchanger 3, and an outer periphery of the heat receiving part 36a to communicate with each other is provided. A guide plate 11 which guides the medium to the communication passage 32 is provided in the medium passage 3a.

Description

  The present invention relates to an exhaust heat recovery apparatus.

  Conventionally, as an exhaust heat recovery device for exhaust gas mounted on both sides, the heat exchanger is opened and closed by a thermo element that is a temperature-actuated actuator according to the temperature of cooling water discharged from the heat exchanger. An exhaust heat recovery device that performs switching control between a first flow path that passes through and a second flow path that bypasses the heat exchanger is known (for example, see Patent Document 1).

JP2011-214529A

  In the conventional exhaust heat recovery apparatus, the valve shaft of the valve body is provided in a direction orthogonal to the axis of the second flow path of the exhaust heat recovery apparatus. The valve shaft of the valve body is rotated by the thermo element, and the heat receiving portion of the thermo element needs to be provided in the pipe through which the cooling water discharged from the heat exchanger passes. The piping of the cooling water needs to be provided on either the left or right with respect to the axis of the second flow path of the exhaust heat recovery device.

  Since the cooling water piping is provided on either the left or right side of the axis of the second flow path of the exhaust heat recovery device, the position of the piping through which the cooling water is passed on the vehicle side on which the exhaust heat recovery device is mounted. If the vehicle side cooling water piping and the thermo-element are located on the opposite side of the axis of the second flow path, the vehicle side cooling water piping is connected to the exhaust heat recovery. It is necessary to bypass the main body of the apparatus and connect to the inlet of the heat exchanger, resulting in a problem that the piping path becomes long.

  Therefore, an object of the present invention is to provide an exhaust heat recovery apparatus that solves the above-described problems.

In order to solve the above-mentioned problem, the invention according to claim 1 is a first flow path through which exhaust gas passes through a heat exchanger for exchanging heat between exhaust gas and a medium in an exhaust system such as an internal combustion engine, A second flow path through which the gas bypasses the heat exchanger, a valve body that opens and closes the second flow path, and a thermo element that opens the valve body when the temperature of the medium reaches a predetermined value or more. Have
The thermo element has a heat receiving portion,
In the heat exchanger, a communication path that communicates the inside of the medium flow path through which the medium flows and the outer periphery of the heat receiving unit is provided,
A guide plate for guiding the medium to the communication path is provided in the medium flow path.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, the medium can flow between the outer edge of the medium flow path in the heat exchanger and the outer end of the guide plate. Is.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the guide plate is provided so as to be orthogonal to the axis of the medium flow path.

  According to a fourth aspect of the present invention, in the first, second, or third aspect of the invention, the communication path is provided so as to straddle the outer end of the guide plate.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the communication path is provided in an upper portion of the heat exchanger.

  According to the present invention, the heat receiving portion of the thermo element is provided not in the flow path from which the medium is discharged from the heat exchanger but in the communication path for taking out the medium from the medium flow path of the heat exchanger. The position of the piping of the medium introduced into the exchanger or discharged from the heat exchanger can be freely set regardless of the position of the thermo element. For example, the inlet / outlet of the medium in the heat exchanger can be set as the axis of the second flow path. It is possible to prevent the restriction of the position of the piping through which the medium passes on the vehicle side where the exhaust heat recovery device is mounted, and to make the exhaust heat recovery device versatile. I can do it.

  In addition, when the medium inlet / outlet port in the heat exchanger is provided at the approximate center in the left-right direction with respect to the axis of the second flow path, the position of the vehicle side medium pipe and the thermo element is the same as in the prior art. Without being positioned on the opposite side of the axis of the two flow paths, the piping path can be shortened and the weight can be reduced.

1 is a front view of an exhaust heat recovery apparatus according to Embodiment 1 of the present invention. The top view of FIG. The left view of FIG. FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. Sectional drawing of the state which opened the 1st valve body from the state of FIG. BB sectional drawing of FIG. The CC sectional view taken on the line of FIG. The DD sectional view taken on the line of FIG. The EE sectional view taken on the line of FIG. FF sectional view taken on the line of FIG. The GG sectional view taken on the line of FIG.

The mode of the present invention is explained based on the example shown in a figure.
[Example 1]
1 to 11 show a first embodiment of the present invention.

  The exhaust heat recovery apparatus 1 of the first embodiment is disposed in an exhaust system of a vehicle or the like using an internal combustion engine, and an upstream exhaust pipe (not shown) is provided on the downstream side of the inlet 1a provided on the upstream side. A downstream exhaust pipe (not shown) is connected to the discharge port 1b.

  As shown in FIG. 4, the exhaust heat recovery apparatus 1 has a case 2, and a heat exchanger 3, a first flow path 4 passing through the heat exchanger 3, and the heat exchanger 3 are included in the case 2. A second flow path 5 that bypasses is provided. The second flow path 5 communicates with the upstream exhaust pipe and the downstream exhaust pipe.

  As shown in FIGS. 1 to 3, the case 2 includes a cylindrical main body 2 a and a reduced diameter portion 2 b provided on the downstream side of the main body 2 a. 3 to 6, the second flow path 5 is formed by a cylindrical tube having both ends open, and as shown in FIG. 5, the second flow path 5 is disposed at the center of the main body 2 a of the case 2. Yes.

  As shown in FIG. 8, two heat exchangers 3 are provided between the main body 2 a of the case 2 and the second flow path 5 so as to be located on both sides of the axis of the second flow path 5. Yes. As shown in FIG. 8, both the heat exchangers 3 and 3 are formed in the circular arc shape centering on the axial center of the main-body part 2a. The heat exchanger 3 has a medium flow path 3a through which a medium such as cooling water of a cooling system such as an internal combustion engine flows, and a fluid flow path 3b through which an exhaust gas fluid flows. As shown in FIGS. 1 to 5, the medium flow path 3a has a medium inlet 10a and a medium outlet 10b, and the medium inlet 10a and the medium outlet 10b are connected to a cooling system such as an internal combustion engine. . Thereby, in the heat exchanger 3, heat exchange can be performed between the medium and the exhaust gas.

  In the state where the exhaust heat recovery apparatus 1 is installed in a vehicle or the like, as shown in FIGS. 1 to 4, the medium inlet 10 a is below the second flow path 5 and the second flow path of the exhaust heat recovery apparatus 1. The medium outlet 10b is located above the second flow path 5 and at a substantially central position in the left-right direction with respect to the axis of the second flow path 5 of the exhaust heat recovery apparatus 1. It is provided to do. The medium flows in from the medium inlet 10a, branches into the left and right medium flow paths 3a, 3a at the branching section 10c, and flows upward in the medium flow paths 3a, 3a from the lower side to the upper side. It merges and is discharged from the medium outlet 10b.

  A cross section perpendicular to the axis of the main body 2a of the case 2 in the fluid flow path 3b is formed in an arc shape as shown in FIG. Further, as shown in FIG. 4, a plurality of fluid flow paths 3b are provided in parallel from the upstream side toward the downstream side. Although the number of the fluid flow paths 3b is arbitrary, in this embodiment, the left and right heat exchangers 3, 3 are each provided with four fluid flow paths 3b. Moreover, although the shape of the fluid flow path 3b is formed arbitrarily, it is preferable to form the outer edge part 3c of the inner peripheral surface in a curved surface shape.

  A plate-shaped guide plate 11 is provided in the medium flow path 3a so as to be orthogonal to the axis. As shown in FIG. 8, the guide plate 11 is provided from the inner end of the medium flow path 3a to the outer edge of the fluid flow path 3b. The guide plate 11 is an outer edge portion of the medium flow path 3a, that is, the medium. It is not provided between the outer edge part 3d of the flow path 3a and the outer end 11a of the guide plate 11, and the medium can be circulated through the communication part 3e provided therebetween. . Further, the guide plate 11 is provided only in the medium flow path 3a and is not provided in the fluid flow path 3b.

  In the main body 2a of the case 2, there is provided a recovery space 13 that is located below the heat exchanger 3 and collects condensed water generated when the exhaust gas exchanges heat in the fluid flow path 3b. A space 14 where exhaust gas flowing through the left and right fluid flow paths 3b merges is provided above the exchanger 3, and the fluid flow path 3b communicates with the recovery space 13 and the space 14, and the fluid flow path 3b and the recovery space 13 and space 14 constitute the first flow path 4. Thus, the heat exchangers 3 and 3 are provided on both side portions in the case 2 and are not provided on the upper and lower portions of the case 2.

  As shown in FIGS. 4 and 6, a communication hole 18 is formed in the lower part of the second flow path 5, and the second flow path 5 communicates with the recovery space 13 through the communication hole 18 and a heat exchanger. 3 fluid flow paths 3b.

  A junction 21 where the second flow path 5 and the first flow path 4 merge is provided downstream of the communication hole 18. The second flow path 5 is formed with a first communication portion 24 that communicates the second flow path 5 and the merging portion 21. Further, the first flow path 4 is formed with a second communication portion 25 that communicates the space 14 of the first flow path 4 and the merging portion 21. The second communication part 25 is formed so as to be positioned above the first communication part 24. The second communication part 25 is formed in a housing 26 provided on the downstream side of the space 14. In the housing 26, only the upstream and downstream second communication portions 25 are opened, and the upstream opening communicates with the space 14.

  As shown in FIG. 9, a valve shaft 27 is provided on the upstream side of the second communication portion 25 so as to penetrate the left and right walls of the housing 26. As shown in FIGS. 4 and 5, the downstream end portion of the housing 26 is formed in an arc shape centering on the valve shaft 27, and the second communication portion 25 is formed in the arc portion.

  The valve shaft 27 is supported by bearings 29 and 29 provided on both sides in the housing 26. A bearing case 34 is provided on the outer periphery of the bearings 29 and 29 over the entire left and right direction of the first flow path 4. The housing 26 and the bearing case 34 prevent the exhaust gas in the first flow path 4 from coming into contact with the valve shaft 27.

  A pair of arm portions 30a, 30a formed on the swing arm type first valve body 30 is fixed to the valve shaft 27 protruding leftward and rightward in the axial direction from the housing 26, and the valve shaft 27 is rotated forward and backward. The first valve body 30 can be rotated forward and backward to open and close the second flow path 5. As shown in FIG. 10, the pair of arm portions 30 a and 30 a are provided in the axial direction of the valve shaft 27 so as to be longer than the length of the second communication portion 25 in the left-right direction. On the side surface of the second flow path 5 of the first valve body 30, a sealing material 30 b that contacts and separates from the first communication portion 24 is fixed.

  As shown in FIG. 9, the valve shaft 27 is provided so that one end side penetrates the case 2, and a seal member 28 is provided on the outer periphery of the valve shaft 27 so as to penetrate the case 2. The seal member 28 has a labyrinth structure that prevents the exhaust gas from leaking out of the case 2.

  In the prior art exhaust heat recovery device, since the bearing is provided so as to penetrate the case, in addition to supporting the valve shaft, this bearing prevents the exhaust gas from leaking outside the case. Since it is necessary to suppress, a bearing becomes large. On the other hand, in the present embodiment, the bearing 29 and the seal member 28 are configured as separate members, and the bearing 29 is provided in the case 2, so that the seal member 28 does not need a function of the bearing, and the exhaust gas is not generated. Since it suffices if leakage from the case 2 can be suppressed, the axial length of the seal member 28 can also be shortened. Further, since the bearing 29 only needs to consider the durability as a bearing, the diameter of the bearing 29 can be made smaller than the diameter of the bearing of the exhaust heat recovery device of the prior art, and the exhaust heat recovery device 1 Can be made smaller than the conventional exhaust heat recovery device.

  In the first valve body 30, a second valve body 31 is formed integrally with the first valve body 30 so as to be positioned between the arm portions 30 a and 30 a. The second valve body 31 is formed in an arc shape centered on the valve shaft 27, and the second valve body 31 is formed on the downstream side portion of the housing 26 by rotating the valve shaft 27 forward and backward. The second communication part 25 can be opened and closed by moving in the vertical direction along the part. The upstream side surface of the second valve body 31 may or may not be provided with a sealing material. In this embodiment, no sealing material is provided.

  The first valve body 30 and the second valve body 31 rotate integrally around the valve shaft 27, and when the first valve body 30 is opened as shown in FIG. Is closed to close the second communication portion 25. Also, as shown in FIG. 4, when the first valve body 30 is closed, the second valve body 31 is opened and the second communication portion 25 is opened. Is to be released.

  The junction 21 and the recovery space 13 communicate with each other through a discharge hole 23a formed at the lower end of the partition wall 23 provided between them, and the condensed water recovered in the recovery space 13 passes through the discharge hole 23a. After being discharged to the merging portion 21, it is discharged to the outside together with the exhaust gas.

  As shown in FIG. 11, a medium outlet 33a and a medium return port 34a are formed on the upper portion of the case 2 in the heat exchanger 3 so as to be separated from each other, and between the outlet 33a and the return port 34a, The outer end 11a of the guide plate 11 is positioned. A guide passage 33 is connected to the outlet 33a to guide the medium in the medium flow path 3a to the outer peripheral portion 35 of the heat receiving portion 36a of the thermoelement 36 which is a temperature-actuated actuator provided outside the case 2, and is connected to the return port 34a. Is connected to a return passage 34 that returns from the outer peripheral portion 35 of the heat receiving portion 36a of the thermo element 36 into the medium flow path 3a. A partition wall 41 is provided between the guide passage 33 and the return passage 34 to partition the outlet 33a portion and the return port 34a portion.

  The communication passage 32 is configured by the guide passage 33, the outlet 33 a, the return passage 34, the return port 34 a, and the outer peripheral portion 35. As shown in FIG. 11, the communication path 32 is formed so as to straddle the outer end 11 a of the guide plate 11.

  When the medium moves from the lower side to the upper side in the medium flow path 3 a of the heat exchanger 3, the medium is guided to the outlet 33 a side by the guide plate 11 and passes through the guide passage 33 and the heat receiving portion 36 a of the thermo element 36. You can touch. Thereafter, the medium passes through the return passage 34 and returns from the return port 34a into the medium flow path 3a.

  By providing the guide plate 11 so as to be orthogonal to the axis of the medium flow path 3a, the guide plate 11 is positioned in a direction orthogonal to the flow of the medium, and the medium can be efficiently guided to the guide passage 33. It can be done.

  If the guide plate 11 is provided up to the outer edge of the medium flow path 3a and the medium flow path 3a is partitioned by the guide plate 11, the outer edge of the medium flow path 3a and the return port 33a are returned. The flow of the medium between the mouth 34a becomes poor, the medium boils at that portion, bubbles are generated, and the bubbles are difficult to move, so that there is a possibility that emptying may occur. Therefore, the guide plate 11 is not provided at the outer edge portion of the medium flow path 3a, and the medium is emptied by circulating the medium between the outer edge portion 3d of the medium flow path 3a and the outer end 11a of the guide plate 11. Can be suppressed.

  In the heat receiving portion 36a of the thermo element 36, wax is stored. A rod 38 urged toward the thermo element 36 by the urging member 37 is in contact with the distal end portion of the thermo element 36. When the wax in the thermo element 36 reaches a predetermined temperature or more, it thermally expands, its tip portion expands, and the rod 38 is pushed and moved by the tip portion, whereby the valve shaft 27 rotates, as shown in FIG. As described above, the first valve body 30 is opened to open the second flow path 5, and the second valve body 31 is closed to close the first flow path 4.

  Further, when the wax in the thermo element 36 becomes lower than a predetermined temperature, the wax contracts, the tip of the wax contracts, the rod 38 is urged by the urging member 37, and the valve shaft 27 rotates, so that FIG. As shown, the first valve body 30 is closed to close the second flow path 5, and the second valve body 31 is opened to open the first flow path 4.

  When the medium of the outer peripheral portion 35 of the heat receiving portion 36a of the thermo element 36 is lower than a predetermined temperature, the second flow path 5 is closed and the first flow path 4 is opened as shown in FIG. From the second flow path 5, the exhaust gas passes through the communication hole 18, passes through the recovery space 13, the fluid flow path 3 b of the heat exchanger 3, and the space 14, and then passes from the second communication section 25 to the merge section 21. It has come to flow.

  By providing the heat receiving part 36a of the thermo element 36 in the communication path 32 for taking out the medium from the medium flow path 3a of the heat exchanger 3, the medium introduced into the heat exchanger 3 or discharged from the heat exchanger 3 is removed. The position of the piping can be freely set regardless of the position of the thermo element 36, and the medium inlet / outlet port 10 a, 10 b in the heat exchanger 3 can be provided at substantially the center in the left-right direction with respect to the axis of the second flow path 4. In addition, on the vehicle side on which the exhaust heat recovery apparatus 1 is mounted, the restriction on the position of the pipe through which the medium passes can be reduced. Thereby, it is not necessary to design the exhaust heat recovery device 1 for each vehicle to be mounted, and the exhaust heat recovery device 1 can be versatile.

  Further, by providing the medium inlet / outlet ports 10a and 10b in the heat exchanger 3 at substantially the center in the left-right direction with respect to the axis of the second flow path 5, the medium on the vehicle side can be provided as in the exhaust heat recovery device of the prior art. The piping to be passed and the position of the thermo element are not located on the opposite side to the axis of the second flow path, so that the medium piping path can be shortened and the weight can be reduced.

  The heat receiving portion 36a of the thermo-element 36 that is a temperature-actuated actuator can come into contact with the medium taken out from the medium flow path 3a of the heat exchanger 3, and thus responds quickly to the temperature of the medium in the heat exchanger 3. Thus, it is possible to prevent the thermoelement 36 from operating and the medium temperature of the heat exchanger 3 from becoming too high.

  Since the medium temperature in the heat exchanger 3 is higher at the upper part, by providing the communication path 32 at the upper part of the heat exchanger 3, the medium at a higher temperature can be brought into contact with the heat receiving part 36 a of the thermo element 36. Therefore, heat can be received from the medium at a high temperature in the heat exchanger 3, the thermo element 36 is operated, the valve bodies 30 and 31 can be opened and closed, and the flow paths 4 and 5 can be switched. The flow paths 4 and 5 can be switched at an appropriate timing in response to the state of the medium.

  The condensed water generated when the exhaust gas is heat-exchanged easily moves downward in the fluid flow path 3b by its own weight and is recovered into the recovery space 13, and then exhausted through the discharge hole 23a and the junction 21. The heat recovery apparatus 1 is discharged downstream. In addition, the plurality of fluid flow paths 3b are arranged side by side from the upstream side to the downstream side, and the condensed water is easily discharged into the recovery space 13 by forming an arc shape that can flow in the vertical direction. When the medium in the medium flow path 3a is boiled or the like and gas (bubbles) is generated, the gas easily moves upward, and the gas in the medium flow path 3a can be easily released upward.

  Further, when the outer edge 3c of the inner peripheral surface of the fluid flow path 3b is formed in a curved shape, the fluid always hits the outer edge 3c of the inner peripheral surface when the fluid flows in the fluid flow path 3b. The turbulent flow of the flowing exhaust gas is promoted, and the heat exchange efficiency of the heat exchanger 3 can be improved.

  On the other hand, when the medium of the heat exchanger 3 is at a predetermined temperature or higher, the second flow path 5 is opened and the first flow path 4 is closed as shown in FIG. Then, it passes through the second flow path 5 and flows to the junction 21.

  The second valve body 31 is disposed between the pair of arm portions 30a, 30a of the first valve body 30, and the first valve body 30 and the second valve body 31 are integrally formed, whereby the second valve body 31 is formed. Since 31 can be disposed in the rotation space of the first valve body 30, the exhaust heat recovery apparatus 1 can be downsized. Moreover, since the 2nd valve body 31 can be simultaneously manufactured in series with the material between the arm parts 30a and 30a of the 1st valve body 30 in the material which manufactures the 1st valve body 30, the material of the 1st valve body 30 The yield and the cost and man-hours can be reduced.

  By providing the recovery space 13 at the lower part of the heat exchanger 3, road surface interference of the heat exchanger 3 can be suppressed when the exhaust heat recovery device 1 is mounted at the lower part of the vehicle.

  Since the bearings 29 and 29 are provided and supported on the housing 26 in the case 2, it is only necessary to provide the sealing member 28 on the outer peripheral wall of the case 2 at the portion through which the valve shaft 27 penetrates. Since the length in the direction of the valve shaft 27 can be shortened, and the bearings 29 and 29 only need to ensure durability as a bearing, the diameter of the bearing 29 can be reduced, and the exhaust heat recovery device 1 can be reduced in size.

  Note that the temperature-actuated actuator may be bimetal or shape memory alloy, and the valve body may be rotated by changing the shape thereof.

  A valve system that opens and closes according to the flow rate of exhaust gas is well known in the exhaust system as a so-called variable valve, and an arbitrary mechanism can be used.

  Further, the partition wall 41 provided between the guide passage 33 and the return passage 34 may not be provided. Moreover, although the 1st valve body 30 and the 2nd valve body 31 were integrally formed, you may form the 1st valve body 30 and the 2nd valve body 31 separately.

[Other Examples]
If the induction plate is provided so as to be orthogonal to the axis of the medium flow path of the heat exchanger, and the medium is guided to the communication path by the induction plate, the heat exchanger, that is, the medium flow path, the fluid The arrangement and shape of the flow path and the shape and position of the guide plate can be arbitrarily set. Note that the guide plate is not provided at the outer edge of the medium flow path, and the communication path is preferably formed so as to straddle the outer end of the guide plate.

  For example, the heat exchanger is formed such that the medium flow path and the fluid flow path of the heat exchanger are stacked one above the other so that the medium flows in the horizontal direction in the heat exchanger, and the medium flow path of the heat exchanger A guide plate may be provided so as to be orthogonal to the shaft core so that the medium can be guided to the communication path by the guide plate.

  In addition, the present invention is not limited to a heat recovery device (heat collector, oil warmer, etc.) in a narrow sense whose main purpose is heat recovery to a medium, but is also a heat exchanger (exhaust cooler or EGR) whose main purpose is cooling exhaust gas. Coolers etc.) are also included as heat recovery devices. Furthermore, the application target is not limited to an internal combustion engine such as a vehicle, but can be applied to an exhaust system of a device that generates any exhaust gas such as a general-purpose engine or a stationary combustion device.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and any design changes that do not depart from the spirit of the present invention are included in the present invention. It is.

1 Exhaust heat recovery device.
3 heat exchanger 3a medium flow path 4 first flow path 5 second flow path 11 guide plate 36 thermo element 36a heat receiving part 32 communication path

Claims (5)

In an exhaust system such as an internal combustion engine, a first flow path through which the exhaust gas passes through a heat exchanger that performs heat exchange between the exhaust gas and the medium, a second flow path through which the exhaust gas bypasses the heat exchanger, A valve body that opens and closes two flow paths, and a thermo element that opens the valve body when the temperature of the medium reaches a predetermined value or more,
The thermo element has a heat receiving portion,
In the heat exchanger, a communication path that communicates the inside of the medium flow path through which the medium flows and the outer periphery of the heat receiving unit is provided,
An exhaust heat recovery apparatus, wherein a guide plate for guiding the medium to the communication path is provided in the medium flow path.   The exhaust heat recovery apparatus according to claim 1, wherein the medium can flow between an outer edge portion of a medium flow path in the heat exchanger and an outer end of the guide plate.   The exhaust heat recovery apparatus according to claim 1, wherein the guide plate is provided so as to be orthogonal to the axis of the medium flow path.   The exhaust heat recovery apparatus according to claim 1, wherein the communication path is provided so as to straddle the outer end of the guide plate. The exhaust heat recovery apparatus according to any one of claims 1 to 4, wherein the communication path is provided in an upper portion of the heat exchanger.

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