JP2007315370A - Exhaust heat recovery exhaust emission control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust heat recovery exhaust emission control device preventive of excessive heat recovery. <P>SOLUTION: The device comprises a catalyst part 20, and an exhaust heat recovery part 22 for performing heat exchange between exhaust gas passing through the catalyst part 20 and a heat exchanging medium. A selector valve 72 is provided between the catalyst part 20 and the exhaust heat recovery part 22 for changing over the flow of exhaust gas. The selector valve 72 selects a low-rate flow path 40 for introducing the exhaust gas passing through the catalyst part 20 via the exhaust heat recovery part 22 to an exhaust flow path on the downstream side or a high-rate flow path 44 for introducing the exhaust gas passing through the catalyst part 20 to an exhaust flow path on the downstream side. The exhaust heat recovery part 22 has an intermediate shell 24 into which an inside shell 1 is inserted and an outside shell 42 covering the outside of the intermediate shell 24. The low-rate flow path 40 is formed between the inside shell 1 and the intermediate shell 24, and the selector valve 72 is mounted at the end of the intermediate shell 24. The end of the intermediate shell 24 extends into a cylindrical shell 46 on the outside of the outside shell 42, and the end of the inside shell 1 on the side of a flow-out port 18 of the catalyst part extends near the selector valve 72. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an exhaust heat recovery exhaust purification apparatus that is provided in an exhaust system of an internal combustion engine and includes a catalyst unit that purifies exhaust by a catalyst and an exhaust heat recovery unit that recovers exhaust heat.

  Conventionally, as disclosed in Patent Document 1, a water chamber for exchanging heat between exhaust gas and cooling water is provided on the outer periphery of a catalyst storage chamber provided with a catalyst for purifying exhaust gas. Exhaust gas purification devices that perform heat recovery have been proposed.

In this exhaust purification apparatus, the catalyst storage chamber is formed of a cylindrical body, and the catalyst is disposed in the cylindrical body. The water chamber is formed between an inner cylinder and an outer cylinder arranged on the same axis, and after passing through the catalyst storage chamber, the exhaust gas passes through a spiral passage between the cylinder and the inner cylinder, It flows through the plurality of heat transfer tubes provided in the exhaust pipe and is discharged from the exhaust collecting chamber to the outside.
JP 2000-257415 A

  However, in such conventional devices, heat is exchanged between the exhaust and the cooling water to recover the exhaust heat. However, since the heat exchange is performed even when the amount of exhaust is large, the temperature of the cooling water rises too much. For example, there is a problem that overheating may be caused.

  An object of the present invention is to provide an exhaust heat recovery exhaust purification device that prevents excessive heat recovery.

In order to achieve this problem, the present invention has taken the following measures in order to solve the problem. That is,
An exhaust heat recovery unit that is provided in an exhaust flow path of an internal combustion engine and includes a catalyst unit that purifies exhaust gas with a catalyst, and that performs heat exchange between the exhaust gas that has passed through the catalyst unit and a heat exchange medium to recover exhaust heat. In the exhaust heat recovery exhaust purification device provided with a section,
A switching valve that switches the flow of the exhaust gas is provided between the catalyst unit and the exhaust heat recovery unit, and the switching valve converts the exhaust gas that has passed through the catalyst unit to the exhaust gas flow downstream through the exhaust heat recovery unit. The exhaust heat recovery exhaust purification apparatus is characterized in that it can be switched between a low flow rate channel leading to the passage and a high flow rate channel leading the exhaust gas passing through the catalyst section to the downstream exhaust channel.

  In addition, the catalyst is disposed in a cylindrical inner shell having an inflow port formed at one end and a catalyst portion outflow port formed at the other end, and the exhaust heat recovery unit includes the inner shell A cylindrical intermediate shell inserted from the catalyst part outflow port side and a cylindrical outer shell that covers the outer side of the intermediate shell are provided, and the low flow passage is formed between the inner shell and the intermediate shell. The switching for performing heat exchange between the exhaust gas passing between the intermediate shell and the outer shell and the heat exchange medium, and opening and closing the end of the intermediate shell at the end of the intermediate shell. While attaching a valve | bulb, it is good also as a structure which provided integrally the cylindrical shell by which the outflow port was provided in the said outer shell. At this time, the end of the intermediate shell to which the switching valve is attached is extended into the cylindrical shell outside the outer shell, and the end of the inner shell on the catalyst part outflow port side is extended to the intermediate shell. It is good also as a structure extended in the vicinity of the said switching valve.

  The switching valve may be configured to include a valve body that is urged in the valve closing direction by the urging member and that receives the pressure of the exhaust gas from the catalyst part outflow port in the valve opening direction. Alternatively, the switching valve may be configured to be switched by an actuator. The exhaust heat recovery unit includes a cylindrical outer jacket whose both ends are in close contact with the inner periphery of the outer shell between the inner periphery of the outer shell and the outer periphery of the intermediate shell. And a cylindrical inner jacket having both ends closely attached to the outer periphery of the intermediate shell, and an outer periphery of the intermediate shell and an inner periphery of the inner jacket A medium flow path between the inner jacket and the outer circumference of the inner jacket, and a heat exchange channel connected to the low flow path may be formed.

  Further, the cylindrical shell on the outflow port side may be connected to the outer shell of a silencer provided in the exhaust passage on the downstream side. In that case, the silencer is formed by attaching an end plate to which an inlet pipe is attached to the cylindrical outer shell, and the outer shell on the side where the end plate is attached to the outflow port side. It is good also as a structure which connected the cylindrical shell.

  The exhaust heat recovery exhaust gas purification apparatus of the present invention can switch the flow of exhaust gas by the switching valve, so that it is possible to prevent excessive heat recovery. Moreover, it can comprise compactly by providing the intermediate | middle shell which inserted the inner shell, and the outer shell which covers the outer periphery of an intermediate | middle shell. In addition, the end of the intermediate shell to which the switching valve is attached extends to the inside of the cylindrical shell, and the end of the inner shell extends to the vicinity of the switching valve so that the switching valve is opened and a high flow rate flow is achieved. When the exhaust is guided to the path, heat exchange between the exhaust and the heat exchange medium of the exhaust heat recovery unit can be suppressed.

  Furthermore, since the switching valve includes a valve body that receives the exhaust pressure in the valve opening direction, the switching valve can be switched according to the exhaust pressure, and the configuration is simplified. It is also easy to switch the switching valve according to the operating state of the internal combustion engine by switching the switching valve with an actuator. In addition, when the exhaust heat recovery unit includes a cylindrical jacket between the outer shell and the intermediate shell, the medium flow path can be easily formed.

  If the cylindrical shell on the outflow port side is connected to the outer shell of the silencer, it can be formed integrally with the silencer, facilitating installation to the vehicle, and an expansion chamber can be formed in the cylindrical shell. Performance is also improved.

The best mode for carrying out the present invention will be described below in detail with reference to the drawings.
As shown in FIG. 1, reference numeral 1 denotes a cylindrical inner shell, and an inflow port 2 is formed at one end of the inner shell 1, and the inflow port 2 is connected to an exhaust passage on the upstream side of an internal combustion engine (not shown). The The inflow port 2 is formed at the end of a cylindrical inflow pipe portion 4, and a tapered pipe portion 6 whose diameter gradually increases is connected to the inflow pipe portion 4. A cylindrical storage tube portion 8 is connected to the tapered tube portion 6, and a catalyst carrier 10 is inserted into the storage tube portion 8 via a spacer 12.

  The catalyst carrier 10 is, for example, a monolithic carrier formed in a honeycomb shape made of a porous ceramic block, and a catalyst is supported on the catalyst carrier 10. When the internal combustion engine is a gasoline engine, a three-way catalyst is supported as a catalyst, and when the internal combustion engine is a diesel engine, a noble metal catalyst and an active oxygen release agent are supported.

  A taper tube portion 14 having a gradually decreasing diameter is connected to the storage tube portion 8, and one end of a cylindrical outflow tube portion 16 is connected to the taper tube portion 14. The other end of the outflow pipe portion 16 is opened to form a catalyst portion outflow port 18. The inflow pipe part 4, the storage pipe part 8, and the outflow pipe part 16 are coaxially arranged. In this embodiment, the inflow pipe part 4, the taper pipe part 6, the storage pipe part 8, the taper pipe part 14, and the outflow pipe. The inner shell 1 is formed by the portion 16, and the catalyst portion 20 is formed by the inner shell 1, the catalyst carrier 10, and the spacer 12.

  An exhaust heat recovery unit 22 is provided on the outer periphery of the catalyst unit 20, and the exhaust heat recovery unit 22 includes a cylindrical intermediate shell 24 into which the inner shell 1 is inserted. The intermediate shell 24 includes a cylindrical large-diameter pipe portion 26 disposed on the outer periphery of the storage pipe portion 8, and a taper pipe portion 28 that gradually decreases in diameter is connected to the large-diameter pipe portion 26. A cylindrical small-diameter pipe portion 30 is connected to the tapered pipe portion 28, and the small-diameter pipe portion 30 is disposed coaxially with the outflow pipe portion 16 of the inner shell 1, and the outflow pipe portion 16 is disposed in the small-diameter pipe portion 30. The outflow pipe part 16 is extended into the small diameter pipe part 30 so that the catalyst part outflow port 18 is disposed in the vicinity of the end of the small diameter pipe part 30 by being inserted.

  A plurality of meshes 32 are arranged at equal intervals in the circumferential direction between the outer periphery of the storage tube portion 8 and the inner periphery of the large-diameter tube portion 26 (see FIG. 3). The mesh 32 forms a gap 34 between the outer periphery of the storage tube portion 8 and the inner periphery of the large-diameter tube portion 26, and the outer periphery of the tapered tube portion 14 of the inner shell 1 and the tapered tube portion of the intermediate shell 24. A gap 36 is formed between the inner periphery of 28.

  Further, a gap 38 is formed between the outflow pipe portion 16 of the inner shell 1 and the small-diameter pipe portion 30 of the intermediate shell 24 to form a double tubular shape. 40 is formed. The catalyst part outflow port 18 of the inner shell 1 is opened in the small diameter pipe part 30, and the catalyst part outflow port 18 communicates with the low flow rate flow path 40.

  The intermediate shell 24 is inserted into a cylindrical outer shell 42, and the outer shell 42 is disposed so as to cover the outer periphery of the large-diameter pipe portion 26. A cylindrical shell 46 is welded to the end of the outer shell 42 and provided integrally.

  The cylindrical shell 46 includes a straight pipe portion 48 connected to the outer shell 42, a tapered pipe portion 50 connected to the straight pipe portion 48 and gradually decreasing in diameter, and a cylindrical outflow pipe connected to the tapered pipe portion 50. Part 52. The outflow pipe portion 52 is opened to form an outflow port 54, and a downstream exhaust passage is connected to the outflow port 54. In this embodiment, a part of the straight pipe portion 48, the tapered pipe portion 50, A high flow passage 55 is formed by the outflow pipe portion 52, and exhaust gas is configured to be guided to a muffler (not shown) through the high flow passage 55. In the present embodiment, the outflow pipe portion 52 is arranged coaxially with the inflow pipe portion 4.

  Between the outer periphery of the large-diameter pipe portion 26 and the inner periphery of the outer shell 42, a cylindrical inner jacket 58 and a cylindrical inner jacket 58 are provided coaxially with the outer shell 42, respectively. Both ends of the outer jacket 56 are expanded radially outward, and the outer periphery of the outer jacket 56 is in close contact with the inner periphery of the outer shell 42. As a result, an outer medium flow path 60 is formed between the inner periphery of the outer shell 42 and the outer periphery of the outer jacket 56.

  Further, both ends of the inner jacket 58 are reduced in diameter radially inward, and the inner periphery of the inner jacket 58 is in close contact with the outer periphery of the large diameter pipe portion 26. Thereby, an inner medium flow path 62 is formed between the outer periphery of the large diameter pipe portion 26 and the inner periphery of the inner jacket 58.

  Further, as shown in FIGS. 1 and 2, a heat exchange channel 64 is formed between the inner periphery of the outer jacket 56 and the outer periphery of the inner jacket 58. The heat exchange flow path 64 is communicated with a gap between the outer periphery of the large-diameter pipe portion 26 and the inner periphery of the outer shell 42 at both ends thereof.

  A cover member 65 is attached to the outer periphery of the storage tube portion 8, and the cover member 65 is fitted to the outer periphery of the outer shell 42. Thereby, an annular chamber 67 is formed in the lid member 65, and the low flow rate channel 40 and one end of the heat exchange channel 64 are communicated with each other via the annular chamber 67. The other end of the heat exchange channel 64 communicates with the straight pipe portion 48 of the cylindrical shell 46.

  Further, at three locations in the circumferential direction, a part of the inner circumference of the outer jacket 56 and a part of the outer circumference of the inner jacket 58 are brought into contact, so that the heat exchange channel 64 is divided into three parts, and FIG. As shown in FIG. 5, a through hole 66 is formed in a part of the contacted portion, and the outer medium flow path 60 and the inner medium flow path 62 are communicated with each other.

  A pair of joint members 68 and 70 are attached to the outer shell 42. One joint member 68 passes through the outer shell 42 and is connected to the outer medium flow path 60, and the other joint member 70 passes through the outer shell 42 and the outer and inner jackets 56, 58 to pass the inner medium flow. It is connected to the path 62. The heat exchange medium can be supplied and discharged between the outer medium flow path 60 and the inner medium flow path 62 via the pair of joint members 68 and 70. In this embodiment, the internal combustion engine (not shown) Engine cooling water is used as a heat exchange medium.

  A switching valve 72 is attached to the end of the small diameter pipe portion 30 of the intermediate shell 24. The switching valve 72 includes a valve main body 74 attached to the small-diameter pipe portion 30 and a valve body 78 supported on the valve main body 74 via a swing shaft 76 so as to be swingable.

  The valve body 74 is formed with a tapered tube portion 80 communicating with the small diameter tube portion 30, and is configured so that the valve body 78 can swing to close and open the tapered tube portion 80. Further, the valve body 78 is biased by a biasing member 82 using a coiled spring disposed coaxially with the swing shaft 76 so that the tapered pipe portion 80 is closed by the valve body 78. Further, the exhaust gas pressure from the catalyst part outflow port 18 is arranged to act on the valve body 78 in the valve opening direction.

Next, the operation of the exhaust heat recovery exhaust purification apparatus of the present embodiment described above will be described.
First, the exhaust gas from the internal combustion engine flows into the inflow pipe portion 4, the taper tube portion 6, and the storage tube portion 8 from the inflow port 2 through the upstream exhaust passage. The exhaust gas is purified by the catalyst when passing through the catalyst carrier 10.

  The exhaust gas that has passed through the catalyst carrier 10 flows into the small-diameter pipe portion 30 from the catalyst portion outflow port 18 through the storage tube portion 8 through the tapered tube portion 14 and the outflow tube portion 16. The pressure of the exhaust gas flowing into the small diameter pipe portion 30 acts on the valve body 78. When the pressure of the exhaust gas is low, the valve body 78 closes the taper pipe portion 80 by the biasing force of the biasing member 82, and the switching valve 72. Keeps the valve closed.

  Therefore, the exhaust gas flows into the low flow channel 40 from the catalyst part outflow port 18 and flows into the heat exchange channel 64 from the low flow channel 40 through the annular chamber 67. When passing through the heat exchange flow path 64, heat exchange is performed between the heat exchange medium of the outer medium flow path 60 and the inner medium flow path 62, the temperature of the heat exchange medium is increased, and the temperature of the exhaust gas is decreased. To do. Exhaust gas that has passed through the heat exchange flow path 64 is guided from the outflow port 54 to the downstream exhaust flow path through the straight pipe portion 48, the tapered pipe portion 50, and the outflow pipe portion 52 of the cylindrical shell 46.

  On the other hand, when the exhaust pressure is high during acceleration or the like, the high pressure exhaust gas flows from the inflow port 2 into the inflow pipe portion 4, the taper tube portion 6, and the storage tube portion 8, and the exhaust gas that has passed through the catalyst carrier 10 is stored. From the pipe part 8, the catalyst part outflow port 18 flows into the small diameter pipe part 30 through the taper pipe part 14 and the outflow pipe part 16. The pressure of the exhaust gas flowing into the small-diameter pipe portion 30 acts on the valve body 78, and the exhaust pressure is high. Therefore, the valve body 78 is separated from the taper pipe portion 80 against the biasing force of the biasing member 82, The switching valve 72 is opened.

  Therefore, the exhaust gas flows directly from the catalyst portion outflow port 18 through the switching valve 72 into the straight pipe portion 48 of the cylindrical shell 46, passes through the high flow passage 55, and is exhausted downstream from the outflow port 54. Guided to the flow path. That is, when the exhaust pressure is high, the switching valve 72 switches the exhaust flow from the low flow channel 40 to the high flow channel 55, and the exhaust directly passes through the high flow channel without passing through the exhaust heat recovery unit 22. 55 flows out from the outflow port 54.

  Therefore, when the exhaust pressure is high, the switching valve 72 is opened, and the exhaust gas is led from the catalyst unit outflow port 18 to the outflow port 54 without passing through the exhaust heat recovery unit 22, and the exhaust gas and the heat exchange medium are exchanged. Since no heat exchange is performed between the two, excessive exhaust heat recovery is prevented.

  In addition, an intermediate shell 24 in which the inner shell 1 in which the catalyst carrier 10 is installed is inserted, and an outer shell 42 that covers the outer periphery of the intermediate shell 24 are provided, and a heat exchange flow path 64 is provided between the intermediate shell 24 and the outer shell 42. Since it is provided, it can be configured compactly.

  The end of the intermediate shell 24 to which the switching valve 72 is attached extends into the cylindrical shell 46, and the end of the inner shell 1 extends to the vicinity of the switching valve 72, so that the catalyst part outflow port 18 can be connected to the medium. It can be separated from the flow paths 60 and 62 in terms of distance. In addition, since the tapered tube portion 14 and the outflow tube portion 16 of the inner shell 1 and the tapered tube portion 28 and the small diameter tube portion 30 of the intermediate shell 24 are configured in a double tubular shape, the switching valve 72 is provided from the inside of the inner shell 1. It is possible to suppress heat exchange between the exhaust and the heat exchange medium of the medium flow paths 60 and 62 when the exhaust is guided to the high flow path 55 via the.

  Furthermore, since the switching valve 72 is switched according to the exhaust pressure, the configuration is simplified. In addition, since the exhaust heat recovery unit 22 includes the cylindrical jackets 56 and 58 between the intermediate shell 24 and the outer shell 42, the medium flow paths 60 and 62 can be easily formed.

  Next, an exhaust heat recovery exhaust purification apparatus of a second embodiment different from the above-described embodiment will be described with reference to FIG. The same members as those in the above-described embodiment are denoted by the same reference numerals, and the corresponding members are denoted by the suffix “a” and the detailed description thereof is omitted. The same applies below.

  In the exhaust heat recovery exhaust purification apparatus of the second embodiment, the inflow port 2a is not coaxial with the catalyst portion outflow port 18, is in a deviated position, and the inflow port 2a is opened obliquely. Further, the cylindrical shell 46a is formed to have a slightly larger diameter toward the outflow port 54a.

  Further, the switching valve 72a is configured to swing the valve body 78a by an actuator (not shown), and the actuator may use a negative supply pressure of the internal combustion engine, or may use an electric motor.

  Further, a cooling water temperature sensor for detecting a cooling water temperature of the internal combustion engine (not shown) is provided, and when the cooling water temperature detected by the cooling water temperature sensor becomes equal to or higher than a predetermined temperature by a control circuit (not shown), the actuator Is driven to open the switching valve 72a.

  In the case of the second embodiment, when the cooling water temperature is high, the switching valve 72a is opened to prevent excessive exhaust heat recovery. Therefore, it is possible to prevent overheating and the like by switching the switching valve 72a in accordance with the operating state of the internal combustion engine so that the cooling water temperature does not rise more than necessary.

Next, a third embodiment in which the exhaust heat recovery exhaust purification apparatus and the silencer of the present embodiment described above are integrally formed will be described with reference to FIG.
A silencer 100 includes a cylindrical outer shell 102, and an end plate 104 is attached to one end of the outer shell 102 and is closed. The other end side of the outer shell 102 is reduced in diameter to form an insertion tube portion 106.

  The outer shell 102 is partitioned by a first separator 108 and a second separator 110, and a first silencing chamber 112 is provided between the end plate 104 and the first separator 108, and the first separator 108 and the second separator 110. A second silencing chamber 114 is formed between the second separator 110 and the outer shell 102, and a resonance chamber 116 is formed between the second separator 110 and the outer shell 102. A plurality of small holes (not shown) are formed in the first separator 108 so that the first silencing chamber 112 and the second silencing chamber 114 communicate with each other.

  An inlet pipe 118 is provided through the end plate 104, the first separator 108, and the second separator 110, and is inserted into the insertion tube portion 106 through the end plate 104, the first separator 108, and the second separator 110. An outlet pipe 120 is provided.

  One end of the inlet pipe 118 is opened outside the outer shell 102, and the other end is opened in the resonance chamber 116. The outlet pipe 120 is closed by inserting a cap 122 at the end on the end plate 104 side, and a downstream exhaust pipe (not shown) is connected to the end inserted into the insertion tube portion 106. A large number of small holes 124 and 126 are formed in the inlet pipe 118 and the outlet pipe 120 of the first silencing chamber 112 and the second silencing chamber 114.

  Exhaust gas that has flowed into the inlet pipe 118 flows into the first silencing chamber 112 and the second silencing chamber 114 from the small hole 124, and exits from the first silencing chamber 112 and the second silencing chamber 114 through the small hole 126. 120. Thereafter, it flows out from the outlet pipe 120 to the downstream exhaust passage.

  The cylindrical shell 46a on the outflow port 54a side of the second embodiment shown in FIG. 4 is fitted on the outer periphery of the outer shell 102 on the end plate 104 side, and is integrally connected by welding or the like. In this embodiment, the outer periphery of the outer shell 42 of the exhaust heat recovery unit 22 is slightly smaller than the outer periphery of the outer shell 102 of the silencer 100, and accordingly, the cylindrical shell 46a is silenced from the exhaust heat recovery unit 22 side. The outer diameter increases toward the container 100 side. By this cylindrical shell 46a, the outer shell 42 of the exhaust heat recovery part 22 and the outer shell 102 of the silencer 100 are integrally connected.

  The exhaust gas flowing into the cylindrical shell 46 a flows into the inlet pipe 118 of the silencer 100. The inside of the cylindrical shell 46a becomes an expansion chamber having a large space, and after the exhaust gas flowing into the cylindrical shell 46a is expanded, the exhaust pipe is guided to the inlet pipe 118 to improve the silencing performance.

  In addition, since the outer shell 42 of the exhaust heat recovery unit 22 and the outer shell 102 of the silencer 100 are integrally connected by the cylindrical shell 46a, they can be attached integrally when attaching to the vehicle. This makes it easy to attach to the vehicle. Further, it is not necessary to provide an exhaust pipe for connecting the outflow port 54a and the inlet pipe 118, and assembly is facilitated.

  In the third embodiment, the silencer 100 is integrally connected to the exhaust heat recovery exhaust purification apparatus of the second embodiment. However, the present invention is not limited to this, and the exhaust heat recovery exhaust purification of the first embodiment is used. The silencer 100 may be integrally connected to the apparatus. In that case, the cylindrical shell 46a of the second embodiment may be used instead of the cylindrical shell 46 of the first embodiment. Also in the case of the third embodiment, a switching valve 72 that is switched by the exhaust pressure may be used, or a switching valve 72a that is switched by an actuator may be used.

  The present invention is not limited to such embodiments as described above, and can be implemented in various modes without departing from the gist of the present invention.

1 is a cross-sectional view of an exhaust heat recovery exhaust purification device as one embodiment of the present invention. It is AA expanded sectional drawing of FIG. It is BB expanded sectional drawing of FIG. It is sectional drawing of the exhaust heat recovery exhaust gas purification apparatus as 2nd Embodiment. It is sectional drawing of the exhaust-heat recovery exhaust purification apparatus which connected the silencer as 3rd Embodiment integrally.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Inner shell 2, 2a ... Inflow port 4 ... Inflow pipe part 8 ... Storage pipe part 10 ... Catalyst carrier 12 ... Spacer 16 ... Outflow pipe part 18 ... Catalyst part outflow port 20 ... Catalyst part 22 ... Exhaust heat recovery part 24 ... Intermediate shell 26 ... Large diameter pipe section 30 ... Small diameter pipe section 40 ... Low flow path 42 ... Outer shell 46, 46a ... Cylindrical shell 52 ... Outflow pipe section 54, 54a ... Outflow port 55 ... High flow path 56 ... Outside Jacket 58 ... Inner jacket 60 ... Outer medium flow path 62 ... Inner medium flow path 64 ... Heat exchange flow path 66 ... Through hole 72, 72a ... Switching valve 74 ... Valve body 76 ... Oscillating shaft 78, 78a ... Valve element 82 ... Biasing member 100 ... silencer 102 ... outer shell 104 ... end plate 118 ... inlet pipe 120 ... outlet pipe

Claims (8)

An exhaust heat recovery unit that is provided in an exhaust flow path of an internal combustion engine and includes a catalyst unit that purifies exhaust gas with a catalyst, and that performs heat exchange between the exhaust gas that has passed through the catalyst unit and a heat exchange medium to recover exhaust heat. In the exhaust heat recovery exhaust purification device provided with a section,
A switching valve that switches the flow of the exhaust gas is provided between the catalyst unit and the exhaust heat recovery unit, and the switching valve converts the exhaust gas that has passed through the catalyst unit to the exhaust gas flow downstream through the exhaust heat recovery unit. An exhaust heat recovery exhaust gas purification apparatus, wherein the exhaust heat recovery exhaust gas purification apparatus is switchable between a low flow rate channel leading to a passage and a high flow rate channel leading the exhaust gas that has passed through the catalyst section to a downstream exhaust channel.   The catalyst unit is arranged in a cylindrical inner shell having an inflow port formed at one end and a catalyst unit outflow port formed at the other end, and the exhaust heat recovery unit has the inner shell at the catalyst unit. A cylindrical intermediate shell inserted from the outflow port side, and a cylindrical outer shell that covers the outer side of the intermediate shell, forming the low flow channel between the inner shell and the intermediate shell, The switching valve for performing heat exchange between the exhaust gas passing between the intermediate shell and the outer shell and the heat exchange medium, and opening / closing the end of the intermediate shell at the end of the intermediate shell; The exhaust heat recovery exhaust purification apparatus according to claim 1, wherein a cylindrical shell having an outflow port is provided integrally with the outer shell.   The end of the intermediate shell to which the switching valve is attached extends to the cylindrical shell outside the outer shell, and the end of the inner shell on the catalyst part outflow port side is the switching valve of the intermediate shell. The exhaust heat recovery exhaust purification device according to claim 2, wherein the exhaust heat recovery exhaust purification device extends in the vicinity of the exhaust gas.   2. The switching valve according to claim 1, further comprising a valve body that is urged in a valve closing direction by an urging member and that receives the pressure of the exhaust gas from the catalyst part outflow port in the valve opening direction. The exhaust heat recovery exhaust purification apparatus according to claim 3.   The exhaust heat recovery exhaust purification apparatus according to any one of claims 1 to 3, wherein the switching valve is switched by an actuator.   The exhaust heat recovery unit includes a cylindrical outer jacket whose both ends are in close contact with the inner periphery of the outer shell between the inner periphery of the outer shell and the outer periphery of the intermediate shell. And a cylindrical inner jacket having both ends closely attached to the outer periphery of the intermediate shell, and an outer periphery of the intermediate shell and an inner periphery of the inner jacket And a heat exchange channel connected to the low flow rate channel is formed between the inner periphery of the outer jacket and the outer periphery of the inner jacket. The exhaust heat recovery exhaust purification apparatus according to any one of claims 2 to 5.   The exhaust heat recovery according to any one of claims 2 to 6, wherein the cylindrical shell on the outflow port side is connected to an outer shell of a silencer provided in the exhaust passage on the downstream side. Exhaust purification device.   The silencer is formed by attaching an end plate to which an inlet pipe is attached to the cylindrical outer shell, and the outer shell on the side where the end plate is attached to the cylindrical shell on the outflow port side. The exhaust heat recovery exhaust purification apparatus according to claim 7, wherein:

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