JP6086837B2 - Exhaust heat recovery device - Google Patents

Description

  The present invention relates to an exhaust heat recovery device that is provided in an exhaust system of a vehicle or the like equipped with an internal combustion engine and recovers exhaust heat and uses it for warming up.

  Conventionally, as this type of exhaust heat recovery device, an exhaust system valve element is opened and closed according to the operating state of an internal combustion engine and the temperature of a medium (cooling water), and an exhaust gas flow path is connected to a heat exchanger on the exhaust system. There is known one that performs switching control to a bypass route that bypasses the route (for example, see Patent Document 1).

  FIGS. 14 to 18 show an example of a conventional exhaust heat recovery apparatus, and the exhaust heat recovery apparatus 101 shown in this figure will be described.

  The exhaust heat recovery device 101 is disposed in an exhaust system of a vehicle or the like that uses an internal combustion engine. An upstream exhaust pipe (not shown) is provided on the upstream side (left side in FIG. 16), and the downstream side (right side in FIG. 16). Are connected to downstream exhaust pipes (not shown). The exhaust heat recovery apparatus 101 includes a case 105, and a flow path 103 that passes through the heat exchanger 102 and a bypass path 104 that bypasses the heat exchanger 102 are provided in the case 105. The path 104 communicates with the upstream exhaust pipe and the downstream exhaust pipe.

  As shown in FIG. 14, the heat exchanger 102 is formed with a medium outlet 102a and a medium inlet 102b. The medium outlet 102a and the medium inlet 102b are connected to a cooling system such as an internal combustion engine (not shown). Heat is exchanged between a medium such as cooling water and the exhaust gas flowing through the heat exchanger 102.

  In the middle of the bypass passage 104, a butterfly-type valve body 106 urged in a direction to close the bypass flow path 104 by a biasing body made of a spring or the like is provided on the valve shaft 106a. The valve shaft 106a is provided so as to be rotatable integrally with the valve shaft 106a. Thereby, when the flow rate of the exhaust gas becomes a predetermined value or more, the valve body 106 rotates in the circumferential direction against the urging force of the urging body to open the bypass path 104. .

  A communication part 107 is formed above the vicinity of the downstream side of the valve body 106 in the bypass path 104, and the flow path 103 and the bypass path 104 communicate with each other through the communication part 107.

  As shown in FIG. 18, a thermo element 110 that is a temperature-actuated actuator is installed outside the heat exchanger 102 so that its heat receiving portion is in contact with a medium that circulates through the heat exchanger 102. When the temperature of the distributed medium reaches or exceeds a predetermined value, the thermo element 110 expands due to thermal expansion of the built-in paraffin wax, and when the temperature of the medium decreases to a predetermined value or less, the paraffin wax contracts. However, it contracts linearly in the opposite direction.

  A rod 111 is connected to the thermo element 110, and the valve body 106 is opened and closed by the rod 111.

  For example, when the temperature of the medium reaches a predetermined value (75 ° C.) or more, the paraffin wax built in the thermo element 110 expands, and the valve body 106 resists the urging force of the urging body in the circumferential direction in FIG. It rotates as shown by a chain line to open the bypass path 104.

WO2006 / 090725

  Under an extremely low temperature environment of −10 ° C. or lower, condensed water is generated due to exhaust heat recovery. If this condensed water remains in the exhaust pipe, the condensed water may freeze when the vehicle stops at night.

  In the conventional exhaust heat recovery apparatus 101, when the temperature of the medium is low, such as when the engine is started, the valve body 106 is closed and the exhaust gas flows into the heat exchanger 102 side. Even if the temperature of the exhaust gas is 400 ° C., the temperature of the exhaust gas after heat exchange in the heat exchanger 102 is reduced to about 50 ° C., and the exhaust gas at this temperature can melt frozen condensed water. There is a risk of malfunction due to frozen condensed water.

  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 problems, the invention according to claim 1 is a heat exchanger for exchanging heat between exhaust gas and a medium in an exhaust system such as an internal combustion engine, and the exhaust gas bypasses the heat exchanger. With a bypass path,
A first valve body and a second valve body are provided, and when the first valve body and the second valve body are closed, the bypass path is closed, and at least one of the first valve body and the second valve body is Open the bypass path when opened,
When the temperature of the medium reaches a predetermined value or more, the first valve body is opened,
The second valve element is opened when the temperature of the outside air becomes a predetermined value or less.

According to a second aspect of the present invention, in the first aspect of the present invention, the first biasing body that biases the first valve body in the closing direction, and the first attachment when the temperature of the medium becomes a predetermined value or more. Providing a first actuator for opening the first valve body against the biasing force of the biasing body;
A second urging body for urging the second valve body in the opening direction and a second actuator for releasing the closed state of the second valve body when the temperature of the outside air becomes a predetermined value or less are provided. It is what.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, a communication hole is provided in the first valve body, and the communication hole is opened and closed by the second valve body. It is.

  According to a fourth aspect of the present invention, in the second or third aspect of the present invention, when the flow rate of the exhaust gas exceeds a predetermined value, the second valve body resists the urging force of the second urging body. The bypass path is closed from the open state.

  The invention according to claim 5 is the invention according to any one of claims 2 to 4, wherein the first actuator and the second actuator are thermo-elements that extend and contract by a built-in wax. To do.

  According to the present invention, when the temperature of the outside air becomes a predetermined value or less, the second valve body is opened to open the bypass path, so that the engine can be started in a cryogenic environment. Even in a state where the temperature of the medium is low, high-temperature exhaust gas that does not pass through the heat exchanger can be sent to the rear of the exhaust heat recovery device, so that frozen condensed water can be melted at an early stage.

The perspective view of the valve body part used for Example 1 of this invention. The cross-sectional schematic diagram of the state which added the action | operation mechanism of the valve body to FIG. The left view of FIG. The right view of FIG. The perspective view of the valve body part used for Example 2 of this invention. The cross-sectional schematic diagram of the state which added the action | operation mechanism of the valve body to FIG. The left view of FIG. The perspective view of the valve body part used for Example 3 of this invention. The left view of the state which added the action | operation mechanism of the valve body to FIG. Sectional drawing of the exhaust heat recovery apparatus which shows an example of Example 5 of this invention. Sectional drawing of the exhaust heat recovery apparatus which shows the other example of Example 5 of this invention. Sectional drawing of the exhaust heat recovery apparatus which shows an example of Example 6 of this invention. Sectional drawing of the exhaust heat recovery apparatus which shows the other example of Example 6 of this invention. The top view of the exhaust heat recovery apparatus of a prior art. 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 HH sectional view taken on the line of FIG.

A mode for carrying out the present invention will be described based on an embodiment shown in the drawings.
[Example 1]
The exhaust heat recovery apparatus 1 of the first embodiment is an embodiment in which the valve body 106 and the operation mechanism of the valve body 106 are improved in the conventional exhaust heat recovery apparatus 101. The structure shown in FIGS. 1 to 4 is adopted. Except for this valve body and its operating mechanism, it is the same as the prior art.

  The exhaust heat recovery apparatus 1 according to the first embodiment includes a first valve body 2 and a second valve body 3 as shown in FIGS.

  The first valve body 2 is provided so as to open and close the flow pipe 120 provided in the middle of the bypass path 104 shown in FIG. 16, and opens and closes the bypass path 104.

  As shown in FIG. 2, two bearings 11 and 11 are fixed to the case 105 shown in FIGS. 16 and 2, and shafts 12 a and 12 b that are rotatably supported by the bearings 11 and 11. The first valve body 2 is fixed to the shafts 12a and 12b.

  The first valve body 2 is a butterfly type valve body and is urged in a direction to close the bypass flow path 104 by a first urging body 15 made of a spring or the like. When the flow rate of the exhaust gas exceeds a predetermined value, the first valve body 2 rotates against the urging force of the first urging body 15 due to the differential pressure across the first valve body 2. The bypass path 104 is opened. In the first embodiment, a torsion coil spring is used as the first biasing body 15.

  A first actuator (thermoelement) 16, which is a temperature-actuated actuator, is fixed to a case 105 outside the heat exchanger 102 so that a heat receiving portion thereof is in contact with a medium flowing through the heat exchanger 102. . When the temperature of the circulated medium (cooling water or the like) reaches a predetermined value or more, the first thermo element 16 expands linearly by expanding due to a phase change of the built-in paraffin wax, etc. When the temperature is lowered, it contracts and linearly contracts in the opposite direction. A rod 17 is connected to the first thermo element 16.

  Further, an operating portion 18 is fixed to one shaft 12a, and an engaging portion 18a is provided in the operating portion 18, and the engaging portion 18a and the rod 17 are in contact with each other. When the rod 17 extends, the engaging portion 18a moves upward in FIG. 3, the shafts 12a and 12b rotate in the counterclockwise direction (arrow A direction) in FIG. 3, and the first valve body 2 The first urging body 15 is opened against the urging force of the first urging body 15. Further, when the rod 17 contracts, the urging force of the first urging body 15 rotates the shafts 12a and 12b in the arrow B direction so that the first valve body 2 is closed.

  In the first embodiment, when the temperature of the medium reaches 75 ° C. or higher, the first valve body 2 starts to open, and when the medium temperature is 80 ° C., the opening degree of the first valve body 2 is 61.7 (deg). When the temperature is 130 ° C., the opening degree of the first valve body 2 is set to a maximum of 85 (deg).

  The first valve body 2 is formed so that its outer peripheral shape is larger than the flow port 120a of the flow pipe 120, and a communication hole 2a penetrating the front and back of the first valve body 2 is formed. When closed, a part of the bypass path 104 is opened by the communication hole 2a.

  A cylindrical hollow portion 12c having both ends opened is formed on the other shaft 12b, and a second shaft 21 is rotatably fitted in the hollow portion 12c. The second valve body 3 is fixed to the second shaft 21. This 2nd valve body 3 is formed in the shape which can open and close the communicating hole 2a formed in the 1st valve body 2. As shown in FIG.

  The second valve body 3 is fixed to the second shaft 21, the operation portion 22 is fixed to the second shaft 21, and the holding member 30 is fixed to the other shaft 12b to which the first valve body 2 is fixed. A second urging body 24 made of a spring or the like is provided between the operation unit 22 and the holding member 30, and the second urging body 24 is used to move the second valve body 3 in the direction to open the communication hole 2 a. Energized. In the present embodiment, a torsion coil spring is used as the second biasing body 24.

  The holding member 30 fixed to the other shaft 12b is fixedly provided with a second actuator (thermoelement) 23, which is a temperature-actuated actuator, so that the heat receiving portion thereof is in contact with the outside air. Rotates integrally with the first valve body 2. The second thermo element 23 linearly contracts by contracting due to the phase change of the built-in paraffin wax when the temperature of the outside air becomes a predetermined value or less, and extends linearly when the temperature of the outside air increases. However, it is configured to elongate and move straight in the opposite direction. A rod 25 is connected to the second thermo element 23.

  An operation portion 22 is fixed to the other shaft 12b side end portion of the second shaft 21. The operation portion 22 is provided with an engagement portion 22a, and the engagement portion 22a and the rod 25 are in contact with each other. . When the rod 25 contracts, the engaging portion 22a moves downward in FIG. 4, the second shaft 21 rotates in the clockwise direction in FIG. 4 (arrow C direction), and the second valve body 3 The opening operation is performed by the biasing force of the two biasing bodies 24. When the rod 25 extends, the second shaft 21 rotates counterclockwise (arrow D direction) in FIG. 4 against the urging force of the second urging body 24, and the second valve body 3 is closed. It is like that.

  In the first embodiment, when the temperature of the medium becomes 0 ° C. or less, the second valve body 3 starts to open, and when the temperature of the medium is −15 ° C., the opening degree of the second valve body 3 is 15 (deg), which is the maximum. It is set to be.

  Thus, since the 2nd valve body 3 rotates with respect to the other axis | shaft 12b, ie, the 1st valve body 2, when the 1st valve body 2 rotates, the 2nd axis | shaft 21, the 2nd valve body 3, the operation unit 22, the second thermo element 23, and the rod 25 rotate integrally with the first valve body 2.

Next, the operating state of the valve bodies 2 and 3 will be described.
When the temperature of the medium is 75 ° C. or less, such as when the engine is started, the first valve body 2 is closed. On the other hand, in an extremely low temperature environment where the temperature of the outside air is not more than a predetermined value (0 ° C. in the present embodiment), the second thermoelement 23 contracts and the second valve 24 is urged by the urging force of the second urging body 24. The body 3 opens and the communication hole 2a opens.

  Thereby, a part of the exhaust gas is sent to the rear through the bypass path 104 without passing through the heat exchanger 102, and the condensed water that has been frozen in the exhaust pipe can be dissolved at an early stage. The problem of the heat recovery apparatus 101 can be solved.

  On the other hand, when the temperature of the medium at the start of the engine or the like is not more than a predetermined value (75 ° C. in this embodiment) and the temperature of the outside air is not less than a predetermined value (0 ° C. in this embodiment), the second valve Since the body 3 is closed, the communication hole 2a remains closed, the bypass passage 104 is closed by the valve bodies 2 and 3, and the entire amount of exhaust gas is sent to the heat exchanger 102. Heat exchange between the two.

  Further, when the temperature of the medium reaches a predetermined value (75 ° C. in this embodiment) or more, the first thermo element 16 expands and the first valve body 2 moves against the urging force of the first urging body 15. The bypass path 104 is opened. At this time, the second valve body 3 also rotates in synchronization with the first valve body 2.

  By using a thermo element as a temperature operation actuator, the exhaust heat recovery device 1 can be made inexpensive and downsized.

  The urging bodies of the valve bodies 2 and 3 may be combined with urging bodies (return springs) included in the thermo element.

  Moreover, if the bypass path 104 and the communication hole 2a can be obstruct | occluded and open | released by the valve bodies 2 and 3, it will not be limited to the shape and structure shown to a figure, It can be set as arbitrary shapes and structures.

  Further, the temperature-actuated actuator may be made of 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.

  Moreover, a heat exchanger, a valve body, a biasing body, etc. can employ | adopt arbitrarily the thing of a conventionally well-known structure.

  The exhaust heat recovery apparatus 1 may be provided with a sound deadening function by providing a sound absorbing material in the bypass path or the heat exchange path.

[Example 2]
In the first embodiment, the second thermo element 23 that operates the second valve body 3, the operation portion 22 and the like are provided on the other shaft 12b side, but these may be provided on the one shaft 12a side. For example, the second embodiment shown in FIGS. 5 to 7 may be configured.

  In one shaft 12A of the second embodiment, similarly to the other shaft 12b, a cylindrical hollow portion 12d having both ends opened is formed. A second shaft 21 is rotatably fitted in the hollow portions 12c and 12d of both shafts 12A and 12b. As in the first embodiment, the first valve body 2 is fixed to the shafts 12A and 12b, and the second valve body 3 is fixed to the second shaft 21.

  An operating portion 18A is fitted and fixed to the outer periphery of one shaft 12A, and one shaft 12A protrudes from a shaft insertion hole 18b formed in the operating portion 18A. The second shaft 21 is rotatably inserted into the hollow portion 12d. As in the first embodiment, the operating portion 18A is provided with an engaging portion 18a, and the rod 17 connected to the first thermo element 16 is in contact with the engaging portion 18a.

  A second thermo element 23A similar to that in the first embodiment is fixed to the operation portion 18A, and the operation portion 22A is fixed to the end of the second shaft 21 on the side of one shaft 12A as in the first embodiment. The operating portion 22A is provided with an engaging portion 22a, and a rod 25A connected to the second thermo element 23A is in contact with the engaging portion 22a.

  Since other structures are the same as those of the first embodiment, the same members are denoted by the same reference numerals and the description thereof is omitted.

Also in the second embodiment, the valve bodies 2 and 3 are opened and closed similarly to the first embodiment.
Also in the second embodiment, the same operations and effects as the first embodiment are achieved.

[Example 3]
In the first and second embodiments, the communication hole 2a is formed in the first valve body 2, and the communication hole 2a is opened and closed by the second valve body 3. However, the communication hole 2a is not formed, and the first The bypass path 104 is closed when the valve body 2 and the second valve body 3 are closed, and the bypass path 104 is opened when at least one of the first valve body 2 and the second valve body 3 is opened. Also good.

  For example, as shown in FIGS. 8 and 9, a first valve body 2B is provided on the upper side of the flow port 120a, and a second valve body 3B is provided on the lower side. By these two valve bodies 2B and 3B, a bypass path is provided. 104 is divided and opened and closed, and as shown by the solid lines in FIGS. 8 and 9, when both valve bodies 2B and 3B are closed, the bypass passage 104 is fully closed (closed), As indicated by a chain line in FIG. 9, a part of the bypass path 104 may be opened when at least one of the first valve body 2B and the second valve body 3B is opened.

  The valve body 2B and the valve body 3B are opened and closed by a similar mechanism using the same thermo elements 16 and 23 as in the first and second embodiments.

Since other structures are the same as those of the first and second embodiments, the same members are denoted by the same reference numerals and description thereof is omitted.
In the third embodiment, the same operations and effects as in the first and second embodiments are achieved.

[Example 4]
In the first to third embodiments, the temperature operation actuator is used as a member for opening and closing the first valve body 2 and 2B and the second valve body 3 and 3B. However, the actuator is limited to the temperature operation actuator. Any can be used. For example, a negative pressure actuator or an electric actuator can be used. When using an actuator other than the temperature-actuated actuator, a sensor for measuring the temperature of the medium or the outside air is installed at a predetermined position, and the first measurement is performed in the same manner as in the first to third embodiments based on the measurement value of the sensor. The opening and closing of the valve bodies 2 and 2B and the second valve bodies 3 and 3B are controlled.

Since other structures and mechanisms are the same as those in the first to third embodiments, description thereof is omitted.
In the fourth embodiment, the same operations and effects as in the first to third embodiments are achieved.

  Further, in the fourth embodiment, when a negative pressure actuator or an electric actuator is used as the actuator, the opening degree of the valve body can be increased and the opening degree can be accurately controlled by the temperature operation actuator. When the valve body is opened, the opening degree can be adjusted so as to close the communication part 107 of the bypass path 104 and the flow path 103. Hot exhaust gas can be sent backwards.

[Example 5]
In the first, second, and fourth embodiments, the first valve body 2 and the second valve body 3 are provided in the middle of the bypass path 104. The valve body 2 and the second valve body 3 may be arranged. For example, it may be arranged as shown in FIGS.

  10 and 11, the valve bodies 2 and 3 are configured in the same structure as in the first, second, and fourth embodiments, and the first valve body 2 is formed with a communication hole 2 a, and the second valve body 3. Thus, the communication hole 2a is opened and closed, and the rotation shaft centers of both valve bodies 2 and 3 are set to be the same. When the first valve body 2 and the second valve body 3 are provided at the junction of the bypass path 104 and the flow path 103, an upstream exhaust pipe (not shown) is provided on the upstream side located on the left side of FIG. A downstream exhaust pipe (not shown) is connected to the downstream side located on the right side of FIG. Further, in the case where the first valve body 2 and the second valve body 3 are provided at the branch portion of the bypass path 104 and the flow path 103, an upstream exhaust pipe (not shown) is provided on the upstream side located on the right side of FIG. However, a downstream exhaust pipe (not shown) is connected to the downstream side located on the left side of FIG.

  In addition, valve seats 103 a and 104 a are provided at the junction or branch of the flow path 103 and the bypass path 104. The valve bodies 2 and 3 are opened and closed by the same mechanism using the same actuators as in the first, second and fourth embodiments. In addition, the 2nd valve body 3 in the present Example 5 is formed in the magnitude | size which can fully close (close | close) the valve seat 103a, as shown in FIG.

  In the above configuration, the bypass passage 104 is closed by closing the valve seat 104a side by the first valve body 2 and the second valve body 3 as shown by the solid line X1 in FIGS. In this state, the first valve body 2 and the second valve body 3 are both opened by rotating in the opening direction, and the valve seat 103a side is closed as shown by the chain line X2 in FIG. The passage 103 is closed so that exhaust gas flows into the bypass passage 104 and does not flow into the heat exchanger 102.

  In addition, when the temperature of the outside air falls below a predetermined value from the state where the first valve body 2 and the second valve body 3 close the bypass path 104, only the second valve body 3 is rotated in the opening direction. Then, the communication hole 2 a of the first valve body 2 is opened, and the exhaust gas flows through the bypass path 104. At this time, the second valve body 3 may be opened to a position where the flow path 103 is not blocked by the second valve body as indicated by a chain line X3 in FIG. 10, or as indicated by a chain line X4 in FIG. The flow path 103 may be closed by the second valve body 3.

  The first valve body 2 and the second valve body 3 are provided at a branch portion between the bypass path 104 and the flow path 103, and as shown by a chain line X3 in FIG. When the exhaust gas flow rate is equal to or higher than a predetermined value, the second valve body 3 is moved to the second urging body 24 due to the balance of the exhaust gas flowing into the bypass passage 104 and the flow path 103. It rotates against the urging force and closes to close the communication hole 2a.

  Since other structures are the same as those of the first, second, and fourth embodiments, the same members are denoted by the same reference numerals and description thereof is omitted.

In the fifth embodiment, the same operations and effects as in the first, second, and fourth embodiments are achieved.
Further, the first valve body 2 and the second valve body 3 are provided at the branch portion of the bypass path 104 and the flow path 103. After the engine is started, the exhaust gas flow rate increases, and the second flow rate is such that the vehicle can be moved. When the second valve body 3 is closed against the urging force of the urging body 24 and the communication hole 2a is closed, the temperature of the outside air is a predetermined value (see FIGS. The flow rate of the exhaust gas flowing to the heat exchanger 102 side when the temperature of the medium is equal to or lower than 0 ° C. in this embodiment and the temperature of the medium is equal to or lower than a predetermined value (75 ° C. in this embodiment) is increased, thereby improving the heat exchange efficiency. Can do.

[Example 6]
In the first to fifth embodiments, the flow path 103 and the bypass path 104 are provided in parallel. For example, the flow path 33 is provided on the outer periphery of the bypass path 32 as in the exhaust heat recovery device 31 illustrated in FIGS. The present invention may be applied to the exhaust heat recovery device 31 provided with the heat exchanger 34.

An embodiment in which the present invention is applied to the exhaust heat recovery apparatus 31 shown in FIGS.
As shown in FIG. 12, the exhaust heat recovery device 31 has an upstream exhaust pipe (not shown) on the upstream side located on the left side in FIG. 12, and a downstream exhaust on the downstream side located on the right side in FIG. Tubes (not shown) are connected to each other.

  The exhaust heat recovery device 31 has a case 41, on the inner side of which a heat exchange pipe 42 is provided substantially concentrically with the case 41 in a liquid-tight manner at the case 41 and both ends thereof. A medium circulation part 44 is formed between the case 41 and a medium such as cooling water circulates in the medium circulation part 44. The cross section in the direction orthogonal to the axial direction of the heat exchange pipe 42 is formed in a wave shape in which a plurality of crests and a plurality of troughs are alternately formed in the circumferential direction, and this trough (groove) is spiral in the axial direction. Is formed.

  A bypass pipe 51 that forms a bypass path 32 is provided inside the heat exchange pipe 42, and a flow path 33 is formed between the bypass pipe 51 and the medium circulation portion 44. The upstream end and the downstream end of the bypass path 32 are opened. In the vicinity of the upstream end of the bypass pipe 51, a plurality of small-diameter communication holes 51a are formed so that the bypass path 32 and the flow path 33 communicate with each other, and exhaust gas in the bypass path 32 flows through the communication holes 51a. 33 can be distributed. When the exhaust gas is circulated, heat exchange is performed between the medium flowing through the medium flow portion 44 and the exhaust gas. The case 41, the medium circulation part 44, and the heat exchange pipe 42 constitute a heat exchanger 34.

  A first valve body 2 (2B) and a second valve body 3 (3B) similar to those of the first to fifth embodiments are provided in the downstream portion of the bypass path 32, and the valve bodies 2 (2B) and 3 (3B) are provided. Thus, the bypass path 32 is opened and closed. The bypass path 32 and the flow path 33 are joined on the downstream side of the valve bodies 2 (2B) and 3 (3B).

  When the second valve body 3 (3B) is opened, the joining portion 55 of the bypass path 32 and the flow path 33 may be closed as shown by a chain line shown in FIG. 13, or the chain line shown in FIG. As such, it may not be blocked.

  In addition, a plurality of heat exchange pipes (heat exchangers) in which spiral grooves are formed are disposed in the flow path 33 formed between the case 41 and the bypass pipe 51 so as to surround the outer periphery of the bypass pipe 51. Thus, when the exhaust gas flows through the flow path, heat exchange may be performed between the medium flowing through the heat exchange pipe and the exhaust gas.

Since the other valve body structures and the opening / closing mechanisms of the valve body are the same as those in the first to fifth embodiments, the same members as those described above are denoted by the same reference numerals and the description thereof is omitted.
Also in the present Example 6, there exists an effect | action and effect similar to the said Examples 1-5.

[Other Examples]
The present invention is not limited to a narrowly-defined heat recovery device (heat collector, oil warmer, etc.) whose main purpose is heat recovery to a medium, but is also a heat exchanger (exhaust cooler, EGR cooler, etc.) whose main purpose is cooling exhaust gas ) Is also included as a heat recovery device. Furthermore, the application target is not limited to an internal combustion engine such as a vehicle, but can be applied to exhaust systems of all exhaust gas generators such as general-purpose engines and stationary combustion devices.

  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.

1,31,101 Exhaust heat recovery device.
2a Communication hole 2, 2B 1st valve body 3, 3B 2nd valve body 15 1st biasing body 16 1st actuator 23,23A 2nd actuator 24 2nd biasing body 32,104 Bypass path 34,102 Heat exchanger

Claims (5)

In an exhaust system such as an internal combustion engine, a heat exchanger for exchanging heat between the exhaust gas and the medium, and a bypass path for the exhaust gas to bypass the heat exchanger,
A first valve body and a second valve body are provided, and when the first valve body and the second valve body are closed, the bypass path is closed, and at least one of the first valve body and the second valve body is Open the bypass path when opened,
When the temperature of the medium reaches a predetermined value or more, the first valve body is opened,
An exhaust heat recovery apparatus characterized in that the second valve body is opened when the temperature of the outside air falls below a predetermined value. A first urging body for urging the first valve body in a closing direction; and opening the first valve body against the urging force of the first urging body when the temperature of the medium exceeds a predetermined value. A first actuator is provided,
A second urging body for urging the second valve body in the opening direction and a second actuator for releasing the closed state of the second valve body when the temperature of the outside air becomes a predetermined value or less are provided. The exhaust heat recovery device according to claim 1.   The exhaust heat recovery apparatus according to claim 1 or 2, wherein a communication hole is provided in the first valve body, and the communication hole is opened and closed by the second valve body.   The second valve body is configured to close the bypass path from an open state against an urging force of the second urging body when an exhaust gas flow rate exceeds a predetermined value. The exhaust heat recovery apparatus according to claim 2 or 3.   The exhaust heat recovery apparatus according to any one of claims 2 to 4, wherein the first actuator and the second actuator are thermo elements that extend and contract by a built-in wax.

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