JP2008025557A - Exhaust heat recovery device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve exhaust heat recovery efficiency while suppressing increase in circulation resistance of exhaust gas in an exhaust heat recovery device comprising a heat exchange path and a bypass path which are concentrically disposed. <P>SOLUTION: This device comprises a jacket 3 disposed within an outer cylinder (casing) 2 so as to form a medium path 11 for circulating a medium with the outer cylinder 2, a bypass pipe 4 for forming the bypass path 12, disposed so as to form the heat exchange path 10 with the jacket 3, and a valve element 5 (switching means) for switching an exhaust gas route to the heat exchange path 10 and the bypass pass 12. A spiral groove 7 is formed on the jacket 3, and projections 8 facing recessed portions 7a of the spiral groove 7 are provided on the inside of the heat exchange path 10. <P>COPYRIGHT: (C)2008,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. Furthermore, 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.
Japanese Utility Model Sho 63-110615

  In such a heat recovery apparatus, it is considered to improve heat recovery efficiency while suppressing an increase in exhaust gas flow resistance by providing, for example, a spiral groove at the interface between the heat exchange path and the medium path. It is done. However, even if the spiral groove is formed deeper in an attempt to further improve the heat recovery efficiency, it is difficult to improve the heat recovery efficiency because the exhaust gas does not flow to the inner part of the groove. The present invention solves such problems, and in an exhaust heat recovery device in which a heat exchange path and a bypass path are concentrically arranged, the exhaust heat recovery efficiency is improved while suppressing an increase in exhaust gas flow resistance. An improved exhaust heat recovery apparatus is provided.

  In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that a medium path is formed between the jacket and the jacket so as to form a medium path through which the medium flows between the casing and the inside of the cylindrical casing. In the exhaust heat recovery apparatus provided with a bypass pipe that forms a bypass path so as to form a heat exchange path and a switching means that switches the exhaust gas path to the heat exchange path and the bypass path, a spiral groove is formed in the jacket The exhaust heat recovery apparatus is characterized in that a projection facing the concave portion of the spiral groove is provided inside the heat exchange path.

  A second aspect of the present invention is the exhaust heat recovery apparatus according to the first aspect of the present invention, wherein the outer diameter of the protrusion is larger than the inner diameter of the spiral groove.

  A third aspect of the present invention is the exhaust heat recovery apparatus according to the first or second aspect, wherein a plurality of the protrusions are formed in a dot shape.

  A fourth aspect of the present invention is the exhaust heat recovery apparatus according to any one of the first to third aspects of the present invention, wherein the protrusion is formed on a bypass pipe.

  A fifth aspect of the present invention is the exhaust heat recovery apparatus according to any one of the first to third aspects of the present invention, wherein the protrusion is formed on a cover pipe provided on an outer periphery of the bypass pipe.

  According to the present invention, the exhaust gas circulates to the inner part of the spiral groove by the protrusion provided inside the heat exchange path, so that the heat recovery efficiency can be improved. At that time, since the exhaust gas swirls and circulates, an increase in the flow resistance of the exhaust gas can be suppressed.

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

  FIG. 1 is a longitudinal sectional view showing an exhaust heat recovery apparatus 1 according to the first embodiment.

  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, a cylindrical 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 apparatus 1, and a lead-out port 2b for deriving. In addition, a jacket 3 in which a plurality of spiral grooves 7 are formed is provided inside the outer cylinder 2 so as to form a medium flow path 11 through which a medium flows between the outer cylinder 2 and the jacket 3. .

  In the central part of the outer cylinder 2, the bypass pipe 4 forming the bypass path 12 is separated from the jacket 3 so as to form a heat exchange path 10 between the outer cylinder 2 and substantially concentric with the outer cylinder 2. Is provided. 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 is urged so as to close the downstream end of the bypass pipe 4 by an urging body (not shown), and opens the downstream end of the bypass pipe 4 as the exhaust gas flow rate increases. The valve body 5 may be configured to open or close the downstream end of the bypass pipe 4 according to conditions such as the exhaust temperature, the internal combustion engine speed, and the medium temperature, for example, by the driving means and the control means.

  A plurality of communication holes 9 are provided on the upstream side of the bypass pipe 4. When the bypass pipe 4 is closed by the valve body 5, exhaust gas is guided to the heat exchange path 10 through the communication holes 9. It has become. Further, the bypass pipe 4 is formed with a plurality of protrusions 8 facing the concave portions 7 a of the spiral groove 7 in the form of dots. Further, the protrusion 8 is set to have an outer diameter larger than the inner diameter of the spiral groove 7 so as to slightly bite into the recess 7 a of the spiral groove 7.

  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. At that time, the exhaust gas circulates while turning along the spiral groove 9, and also circulates to the inner part of the recess 7 a of the spiral groove 9 by the protrusion 8 formed on the bypass pipe 4. For this reason, it is possible to improve the heat recovery efficiency while suppressing an increase in the flow resistance of the exhaust gas.

  Thereafter, when heat recovery is no longer necessary, the valve body 5 is controlled so as to open the downstream end of the bypass pipe 4, and most of the exhaust gas passes through the bypass path 12 having a low resistance to the downstream exhaust pipe K. Led.

    FIG. 2 is a longitudinal sectional view showing the exhaust heat recovery device 21 of the second embodiment.

  The second embodiment is different from the first embodiment in that the cover pipe 33 is disposed so as to include the sound deadening layer 34 on the outer periphery of the bypass pipe 4 and a plurality of protrusions 28 are formed on the cover pipe 33. The protrusion 28 is formed in a louver shape having an opening that cuts and raises the cover pipe 33 and communicates the heat exchange path 10 and the sound deadening layer 34. 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. Furthermore, when the exhaust gas flows through the heat exchange path 10, the exhaust noise can be communicated with the silencing layer 34, so that the exhaust noise can be reduced.

  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.

1 is a longitudinal sectional view showing an exhaust heat recovery apparatus according to Embodiment 1 of the present invention. The longitudinal cross-sectional view which shows the exhaust heat recovery apparatus of Example 2 of this invention.

Explanation of symbols

1,21 Exhaust heat recovery device 2 Outer cylinder (casing)
3 Jacket 4 Bypass pipe 5 Valve body (switching means)
7 Spiral groove 8 Protrusion 10 Heat exchange path 11 Medium flow path 12 Bypass path 33 Cover pipe

Claims (5)

  Inside the cylindrical casing, a jacket so as to form a medium path through which the medium flows, and a bypass pipe forming a bypass path so as to form a heat exchange path between the jacket and the casing In the exhaust heat recovery apparatus provided with switching means for switching the exhaust gas path between the heat exchange path and the bypass path, a spiral groove is formed in the jacket, and a protrusion facing the concave portion of the spiral groove is exchanged with the heat. An exhaust heat recovery device provided inside the path.   The exhaust heat recovery apparatus according to claim 1, wherein an outer diameter of the protrusion is larger than an inner diameter of the spiral groove.   The exhaust heat recovery apparatus according to claim 1, wherein a plurality of the protrusions are formed in a dot shape.   The exhaust heat recovery apparatus according to claim 1, wherein the protrusion is formed on a bypass pipe.   The exhaust heat recovery apparatus according to claim 1, wherein the protrusion is formed on a cover pipe provided on an outer periphery of the bypass pipe.

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