JP2007032561A - Exhaust gas heat recovery device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact exhaust gas heat recovery device capable of suppressing overheating of a medium. <P>SOLUTION: In this exhaust gas heat recovery device 1 constituted by arranging a heat exchange path 10 for exchanging heat of exhaust gas and the medium adjacent to a bypass path 4 detouring the heat exchange path 10 and providing a switching means 5 for switching the heat exchange path 10 and the bypass path 4, a thermal insulation member 7 is provided as a heat insulating means between the heat exchange path 10 and the bypass path 4 to form a heat insulating layer 8. <P>COPYRIGHT: (C)2007,JPO&INPIT

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 collects exhaust heat and uses it for warming up.

Conventionally, as this type of exhaust heat recovery device, when the vehicle is cold, exhaust gas is guided to a heat exchange path so that the recovered exhaust heat is used for warming up an internal combustion engine or the like. A system that reduces the load on a cooling system by introducing exhaust gas to a bypass path is known. Further, for example, the exhaust heat recovery apparatus described in Patent Document 1 is intended to make the exhaust heat recovery apparatus compact by arranging the heat exchange path and the bypass path concentrically adjacent to each other.
Japanese Utility Model Sho 63-110615

  However, the exhaust heat recovery apparatus described in Patent Document 1 also transmits exhaust heat to the heat exchange path side through the wall surface of the bypass path even when the exhaust gas is guided to the bypass path side after warm-up, Sometimes overheated. For this reason, there was a concern that the load on the cooling system would be excessive.

  In order to solve the above-mentioned problem, the invention according to claim 1 is provided with a heat exchange path for exchanging heat between the exhaust gas and the medium and a bypass path for bypassing the heat exchange path adjacent to each other, In the exhaust heat recovery apparatus provided with a switching means for switching between a heat exchange path and a bypass path, the exhaust heat recovery apparatus is characterized in that a heat insulating means is provided between the heat exchange path and the bypass path.

  The invention according to claim 2 is the exhaust heat recovery apparatus according to claim 1, wherein the bypass path is coaxially disposed inside the heat exchange path.

  The invention according to claim 3 is the exhaust heat recovery apparatus according to claim 1 or 2, wherein a heat insulating member is provided between the heat exchange path and the bypass path to form a heat insulating layer. It is.

  A fourth aspect of the present invention is the exhaust heat recovery apparatus according to the third aspect of the present invention, wherein the medium flow path through which the medium flows and the heat shield member are provided so as to be separated from each other.

  A fifth aspect of the present invention is the exhaust heat recovery apparatus according to the third or fourth aspect of the present invention, wherein a heat insulating material is disposed in the heat insulating layer.

  A sixth aspect of the present invention provides the exhaust heat recovery according to the third to fifth aspects of the present invention, wherein a small hole capable of communicating with the heat insulating layer is provided in at least one of the heat shield member or the bypass path. Device.

  According to the present invention, by providing the heat insulating means, it is possible to suppress the exhaust heat from being transmitted to the heat exchange path side through the wall surface of the bypass path and overheating of the medium. Therefore, an overload to the cooling system can be suppressed.

  According to the fourth aspect of the present invention, it is possible to further reduce exhaust noise when exhaust gas is led to the bypass path.

  The best mode for carrying out the present invention will be described based on the embodiment shown in FIGS.

  FIG. 1 is a view showing an exhaust heat recovery apparatus 1 of Embodiment 1, and (a) is a longitudinal sectional view. (B) is the sectional view on the AA line in (a).

  The exhaust heat recovery device 1 is disposed in an exhaust system such as a vehicle, and as shown in FIG. 1, an upstream exhaust pipe J is connected to the upstream side, and a downstream exhaust pipe K is connected to the downstream side. As a casing of the exhaust heat recovery apparatus 1, an outer cylinder 2 drawn at both ends is provided. The outer cylinder 2 is formed with an introduction port 2a for introducing a medium that exchanges heat with the exhaust gas into the exhaust heat recovery device, and a lead-out port 2b for deriving. Further, a jacket 3 having a plurality of spiral grooves 3 a formed therein is provided inside the outer cylinder 2, so that a medium can flow through a medium flow path 11 formed between the outer cylinder 2 and the jacket 3. It has become.

  A bypass pipe 4 that forms a bypass path is provided concentrically with the outer cylinder 2 at the center of the outer cylinder 2. A valve body 5 as switching means is provided at the downstream end of the bypass pipe 4 so as to be rotatable about the valve shaft 6. The valve body 5 opens or closes the downstream end of the bypass pipe 4 by driving means and control means (not shown) according to conditions such as exhaust temperature, internal combustion engine speed, and medium temperature.

  As a heat insulating means, a heat insulating layer 8 is formed on the outer periphery of the bypass pipe 4, and a heat shield member 7 is provided apart from the medium flow path 11. A plurality of communication holes 9 are provided on the upstream side of the bypass pipe 4, and when the bypass pipe 4 is closed by the valve body 5, the exhaust gas passes through the communication holes 9 and the jacket 3 and the heat shield member. 7 is led to the heat exchange path 10 formed between the two.

  The operation of the exhaust heat recovery apparatus 1 according to the first embodiment will be described. For example, the valve body 5 is controlled so as to close the downstream end of the bypass pipe 4 when the medium does not reach a predetermined temperature in the unwarmed state and heat recovery is required. Therefore, the exhaust gas guided from the upstream side exhaust pipe J flows through the heat exchange path 10 from the communication hole 9 provided in the bypass pipe 4 and exchanges heat with the medium via the jacket 3. Then, it is guided to the downstream exhaust pipe K.

  Thereafter, when heat recovery becomes unnecessary, the valve body 5 is controlled so as to open the downstream end of the bypass pipe 4, and the exhaust gas is guided to the downstream exhaust pipe K through the bypass pipe 4 having a low resistance. . At this time, the heat shielding member 7 and the heat insulating layer 8 which are heat insulating means prevent the exhaust heat of the exhaust gas passing through the bypass pipe 4 from being transferred to the heat exchange path 10. Therefore, it can suppress that a medium is overheated.

  By degassing the inside of the heat insulating layer 8 to form a vacuum heat insulating layer, the above-described effects can be further exhibited. Further, a heat insulating material such as a fiber, sponge, or granule formed of glass or ceramic containing alumina or silica as a main component may be provided. Moreover, it is good also as a heat insulation means by providing a heat insulating material, without providing the heat-shielding member 7. FIG.

  In the first embodiment, the heat shield member 7 is provided outside the bypass pipe 4. However, the heat shield member 7 may be provided inside the bypass pipe 4 to form the heat insulating layer 8.

  In the first embodiment, the jacket 3 is provided on the inner side of the outer cylinder 2 to exchange heat with the medium. However, heat exchange is performed by a well-known multi-tube type heat exchanger. May be.

  Moreover, in the said Example 1, although the bypass path was located in the center side of the outer cylinder 2, you may make it a bypass path become the outer side of a heat exchange path | route. Further, the heat exchange path and the bypass path are not limited to the concentric shape, and can be arbitrarily adjacent to each other.

    FIG. 2 is a view showing the exhaust heat recovery device 21 of the second embodiment, and (a) is a longitudinal sectional view. (B) is the BB sectional view taken on the line in (a).

  In Example 2, glass wool 32, which is a heat insulating material indicated by hatching in the drawing, is disposed so as to substantially fill the heat insulating layer 8, and a plurality of small holes 33 that can communicate with the heat insulating layer 8 are provided in the bypass pipe 4. This is different from Example 1. In addition, the same code | symbol is provided to the structure same as Example 1, and the description is abbreviate | omitted.

  The second embodiment also exhibits the same effects as the first embodiment. Further, when the exhaust gas flows through the bypass pipe 4, the exhaust noise reaches the glass wool 32 through the small hole 33. For this reason, exhaust noise can be reduced by the resonance effect by a small hole and the silencing effect by glass wool.

  Also in the second embodiment, the same design change as that shown in the first embodiment can be applied as appropriate. Further, the glass wool 32 may not be provided in the heat insulating layer 8 and only the small holes 33 may be provided. Furthermore, the silencing performance can be improved by making the small hole 33 into a louver hole or the like.

  FIG. 3 is a longitudinal sectional view showing the exhaust heat recovery apparatus 41 of the third embodiment.

  In the exhaust heat recovery device 41 of the third embodiment, a small hole 34 that can communicate with the glass wool 32 is also provided in the heat shield member 3. The small holes 34 are provided on the upstream side, and the small holes 33 are provided on the downstream side. Further, a cover pipe 35 having a plurality of small holes 36 is provided inside the outer cylinder 2, and a glass wool 37 (shown by hatching) is provided in a gap formed between the cover pipe 35 and the outer cylinder 2. Yes. In addition, the same code | symbol is provided to the structure same as Example 2, and the description is abbreviate | omitted.

  Example 3 also exhibits the same function and effect as Example 2. Furthermore, exhaust noise when exhaust gas flows through the heat exchange path 10 can be reduced.

  Also in the third embodiment, the same design change as that shown in the first embodiment can be applied as appropriate.

  FIG. 4 is a longitudinal sectional view showing the exhaust heat recovery apparatus 51 of the fourth embodiment.

  The exhaust heat recovery device 51 includes a catalyst carrier 52 having a holding mat 53 wound around the front portion of the exhaust heat recovery device 21 of the second embodiment, and a cone 54 that is connected to the bypass pipe 4. It is. In addition, the same code | symbol is provided to the structure same as Example 2, and the description is abbreviate | omitted.

  The fourth embodiment also exhibits the same effects as the second embodiment. Furthermore, the exhaust heat of the exhaust gas heated to high temperature by the catalytic action can be quickly recovered, and the exhaust heat recovery efficiency can be improved. Further, as in this embodiment, it can be made compact by integrating with a catalyst carrier, a diesel particulate filter, etc., and the vehicle mounting property can be improved.

  In the fourth embodiment, design changes similar to those shown in the first and second embodiments can be applied as appropriate. The catalyst carrier 52 can be replaced with a diesel particulate filter or the like.

  FIG. 5 is a view showing an exhaust heat recovery apparatus 61 of Example 5, and (a) is a longitudinal sectional view. (B) is CC sectional view taken on the line in (a).

  The exhaust heat recovery device 61 is configured such that a bypass path is formed between the outer cylinder 2 and the inner cylinder 62 by arranging an inner cylinder 62 coaxially inside the outer cylinder 2. Further, a cylindrical heat shield member 7 is provided on the outer periphery of the inner cylinder 62 to form the heat insulating layer 8, and the glass wool 32, which is a heat insulating material, is disposed so as to substantially fill the heat insulating layer 8.

  Inside the inner cylinder 62, a medium pipe 63 having caps 64 at both ends is disposed coaxially, and a medium flow path 11 is formed by providing an introduction port 63a and a discharge port 63b. Petal-like heat transfer fins 65 are provided on the outer periphery of the medium pipe 63 to improve the heat exchange efficiency when the exhaust gas passes through the heat exchange path 10 formed between the inner cylinder 62 and the medium pipe 63. It ’s like that. In addition, a separator 66 having a large number of communication holes 66 a is provided at the rear end portion of the outer cylinder 2 so that exhaust noise is reduced when the exhaust gas passes through the separator 66. In addition, the same code | symbol is provided to the structure same as Example 2, and the description is abbreviate | omitted.

  The fourth embodiment also exhibits the same effects as the second embodiment. Moreover, it can be made compact by integrating an arbitrary silencing structure as in this embodiment, and the vehicle mountability can be improved.

  Also in the fifth embodiment, the same design change as that shown in the first and second embodiments can be applied as appropriate.

  FIG. 6 is a longitudinal sectional view showing the exhaust heat recovery apparatus 71 of the sixth embodiment.

  In the exhaust heat recovery device 71, the inside of the outer cylinder 2 is partitioned into two flow paths by a partition plate 74, and connection pipes 72 and 73 are provided at both opening ends of the outer cylinder 2. A bypass pipe 4 that forms a bypass path is disposed in one of the partitioned flow paths. In the heat insulating layer 8 on the outer periphery of the bypass pipe 4, the glass wool 32, which is a heat insulating material, is disposed so as to substantially fill the heat insulating layer 8 as in the second embodiment. The other flow path is the heat exchange path 10, and a medium pipe 75 formed in a spiral shape is provided therein. Further, a valve body 5 as a switching means is provided inside the connection pipe 72 on the upstream side so as to be rotatable about the valve shaft 6. In addition, the same code | symbol is provided to the structure same as Example 2, and the description is abbreviate | omitted.

  FIG. 7 is a longitudinal sectional view showing the exhaust heat recovery apparatus 81 of the seventh embodiment.

  The exhaust heat recovery device 81 is provided with a bypass pipe 4 and an inner cylinder 82 that are bypass paths through the outer cylinder 2, and connection pipes 84 and 85 that connect the bypass pipe 4 and the inner cylinder 82. Yes. As in the second embodiment, the heat insulating layer 8 in the outer cylinder 2 is disposed so as to be substantially filled with glass wool 32 which is a heat insulating material. The jacket 3 is provided inside the inner cylinder 82, and the heat exchange path 10 and the medium flow path 11 are formed. Further, the valve body 5 as a switching means is provided inside the connection pipe 84 on the upstream side so as to be rotatable about the valve shaft 6. In addition, the same code | symbol is provided to the structure same as Example 2, and the description is abbreviate | omitted.

  Also in Example 6 and Example 7, the same effect as Example 2 is exhibited. In addition, the same design changes as those shown in the first and second embodiments can be applied as appropriate.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and design changes within a range that does not depart from the spirit of the present invention are included in the present invention. In addition, heat exchangers (exhaust coolers, EGR coolers, etc.) whose main purpose is cooling of exhaust gas are not limited to heat recovery devices (heat collectors, oil warmers, etc.) in a narrow sense whose main purpose is heat recovery to the medium. It is 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.

BRIEF DESCRIPTION OF THE DRAWINGS The exhaust-heat recovery apparatus of Example 1 of this invention is shown, (a) is the longitudinal cross-sectional view, (b) is the AA sectional view taken on the line in (a). The exhaust heat recovery apparatus of Example 2 of this invention is shown, (a) is the longitudinal cross-sectional view, (b) is the BB sectional drawing in (a). The longitudinal cross-sectional view which shows the exhaust heat recovery apparatus of Example 3 of this invention. The longitudinal cross-sectional view which shows the exhaust heat recovery apparatus of Example 4 of this invention. The exhaust heat recovery apparatus of Example 5 of this invention is shown, (a) is the longitudinal cross-sectional view, (b) is CC sectional view taken on the line in (a). The longitudinal cross-sectional view which shows the exhaust heat recovery apparatus of Example 6 of this invention. The longitudinal cross-sectional view which shows the exhaust heat recovery apparatus of Example 7 of this invention.

Explanation of symbols

1, 21, 41, 51, 61, 71, 81 Exhaust heat recovery device 2 Outer cylinder 3 Jacket 4 Bypass pipe (bypass path)
5 Valve body (switching means)
7 Heat shield member (heat insulation means)
8 Insulation layer (insulation means)
10 Heat Exchange Path 11 Medium Channel 32 Glass Wool (Insulation)
33,34 Small hole

Claims (6)

  Exhaust heat recovery provided with a heat exchanging path for exchanging heat between the exhaust gas and the medium and a bypass path bypassing the heat exchanging path, and provided with a switching means for switching between the heat exchanging path and the bypass path An exhaust heat recovery apparatus according to claim 1, wherein a heat insulating means is provided between the heat exchange path and the bypass path.   The exhaust heat recovery apparatus according to claim 1, wherein the bypass path is coaxially disposed inside the heat exchange path.   The exhaust heat recovery apparatus according to claim 1 or 2, wherein a heat insulating member is provided between the heat exchange path and the bypass path to form a heat insulating layer.   The exhaust heat recovery apparatus according to claim 3, wherein a medium flow path through which the medium flows and the heat insulating layer are provided so as to be separated from each other.   The exhaust heat recovery apparatus according to claim 3 or 4, wherein a heat insulating material is disposed in the heat insulating layer.   The exhaust heat recovery apparatus according to claim 3, wherein a small hole capable of communicating with the heat insulating layer is provided in at least one of the heat shield member and the bypass path.

Images