JP2014109391A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve performance for cooling a fluid that is a cooling target.SOLUTION: A heat exchanger includes: a heat exchange element in which a plurality of tubular paths through which a fluid that is a cooling target passes; a housing member that is arranged around the heat exchange element, and that forms an outer-circumference refrigerant path between the housing member and the heat exchange element through which refrigerant exchanging heat with the heat exchange element circulates; and an internal refrigerant path that communicates with the outer-circumference refrigerant path, and that introduces the refrigerant in the outer-circumference refrigerant path into the heat exchange element. The heat exchanger can also remove heat from the neighborhood of a central portion of the heat exchange element by introducing the refrigerant into the neighborhood of the central portion. As a result, the heat exchanger has improved performance for cooling the fluid that is the cooling target as compared with a heat exchanger that is not provided with the internal refrigerant path. Furthermore, a contact area between the heat exchange element and the refrigerant increases by providing the internal refrigerant path, in which respect, too, the performance of the heat exchanger for cooling the fluid that is the cooling target is improved.

Description

  The present invention relates to a heat exchanger.

  Conventionally, for example, a heat exchanger for cooling EGR (Exhaust Gas Recirculation) gas included in an exhaust gas recirculation device is known. Further, a heat exchanger using ceramic is known (for example, Patent Document 1), and this can also be used for an EGR gas cooling device. In Patent Document 1, a first fluid circulation part formed by a honeycomb structure having a plurality of cells through which a heating body as a first fluid circulates, and a first fluid circulation part provided on the outer periphery of the first fluid circulation part. A heat exchanger having a two-fluid circulation part is disclosed. The refrigerant flows through the second fluid circulation portion, takes heat from the heating element that circulates in the first fluid circulation, and cools the heating element. Further, Patent Document 2 discloses a heat storage body having a honeycomb structure, a fluid flow path through which a fluid flows, and a heat storage medium portion in which a medium for storing heat of the fluid is contained. In the heat storage body disclosed in Patent Literature 2, heat exchange is performed between the medium enclosed in the heat storage medium section and the fluid flowing through the fluid flow path.

International Publication No. 2011/071161 JP 2011-52919 A

  However, in the heat exchanger disclosed in Patent Document 1, since the refrigerant is circulated around the outer peripheral portion of the honeycomb structure, the vicinity of the central portion of the honeycomb structure is difficult to be cooled, and there is sufficient heating body to be cooled. It may not be cooled down. Further, the medium in the heat storage body disclosed in Patent Document 2 is enclosed in a heat storage medium portion formed by plugging both end faces of the honeycomb, and there is room for improvement from the viewpoint of fluid cooling. There is.

  Then, the heat exchanger of this specification indication makes it a subject to improve the cooling performance of the fluid used as cooling object.

  In order to solve the above problems, a heat exchanger disclosed in this specification includes a heat exchanger formed with a plurality of tubular passages through which a fluid to be cooled passes, and is disposed around the heat exchanger, and the heat exchanger A housing member that forms an outer periphery refrigerant passage through which a refrigerant that exchanges heat with the heat exchanger flows between the exchanger and the outer periphery refrigerant passage, and the heat exchange of the refrigerant in the outer periphery refrigerant passage An internal refrigerant passage leading to the inside of the body.

  By providing the internal refrigerant passage, the refrigerant is guided to the inside of the heat exchanger, and the cooling performance of the fluid to be cooled can be improved.

  The internal refrigerant passage may be provided radially from the center of the heat exchange body toward the outer peripheral cooling passage when the heat exchange body is viewed from the flow direction of the fluid to be cooled. Since the distance between the arbitrary tubular passage provided in the heat exchanger and the refrigerant is shortened, the fluid flowing in the tubular passage can be effectively cooled.

  The internal refrigerant passage may cross the heat exchanger and connect between the outer peripheral refrigerant passages. By creating a flow of refrigerant between the outer peripheral refrigerant passages through the internal refrigerant passage, the cooling efficiency can be improved.

  According to the heat exchanger disclosed in this specification, it is possible to improve the cooling performance of the fluid to be cooled.

FIG. 1A is an explanatory view of the heat exchanger according to the first embodiment viewed from the inlet side of a fluid to be cooled, and FIG. 1B is a cross-sectional view taken along line AA in FIG. It is. FIG. 2 is an explanatory diagram with a cross section of the heat exchanger at a location corresponding to the line BB in FIG. FIG. 3 is an explanatory view schematically showing the circulation of the refrigerant in the heat exchanger. FIG. 4A is an explanatory view of the heat exchanger according to the second embodiment viewed from the inlet side of the fluid to be cooled, and FIG. 4B is a cross-sectional view taken along the line CC in FIG. .

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. However, in the drawings, the dimensions, ratios, and the like of each part may not be shown so as to completely match the actual ones.

(First embodiment)
First, the heat exchanger 1 of the first embodiment will be described with reference to FIGS. FIG. 1A is an explanatory view of the heat exchanger 1 according to the first embodiment viewed from the inlet side of a fluid to be cooled, and FIG. 1B is a cross-sectional view taken along line AA in FIG. FIG. FIG. 2 is an explanatory diagram with a cross section of the heat exchanger at a location corresponding to the line BB in FIG. FIG. 3 is an explanatory view schematically showing the circulation of the refrigerant in the heat exchanger. The heat exchanger 1 can cool various fluids. In the first embodiment, the heat exchanger 1 is incorporated in an exhaust gas recirculation device equipped in an internal combustion engine and cools an EGR (Exhaust Gas Recirculation) gas. Used as a cooler. That is, the fluid to be cooled is EGR gas.

  The heat exchanger 1 includes a heat exchanger 2 in which a plurality of tubular passages 2a through which EGR gas to be cooled passes are formed. The heat exchanger 2 is made of silicon carbide (SiC) ceramic. The ceramic material has efficient heat conduction and can exhibit high corrosion resistance. For this reason, a ceramic material having a high thermal conductivity is suitable as a material for the heat exchanger 2. The heat exchange element 2 includes a plurality of tubular passages 2a by having a honeycomb structure or a structure similar to a honeycomb structure. Here, the description of the structure similar to the honeycomb structure is intended to indicate that the shape of the tubular passage 2a is not limited to the hexagonal column shape, but may be, for example, a rectangular column shape or other shapes.

  The heat exchange element 2 includes a landfill portion 2b provided by landfilling a tubular passage 2a in a region from the outer peripheral edge toward the inside. Referring to FIG. 1A, the landfill portion 2b is provided at four positions with a 90 ° shift. The position and number of the landfill portions 2b are not limited to these, but when the landfill portion 2b is provided, the influence of pressure loss on the EGR gas flow is taken into consideration. The landfill part 2b uses the same material as the material of the heat exchanger 2. The landfill 2b can be molded by embedding a material in a desired partial tubular passage 2a after the heat exchanger 2 is extruded. The landfill portion 2a can be formed by other methods. Each landfill 2 a is provided over the entire length of the heat exchange element 2. Each landfill 2a is provided with a groove by cutting along the longitudinal direction of the heat exchange element 2. This groove becomes the internal refrigerant passage 2c. The internal refrigerant passage 2c communicates with an outer peripheral refrigerant passage 4 described later, and guides the refrigerant in the outer peripheral refrigerant passage 4 to the inside of the heat exchanger. In addition, the width | variety and length of the internal refrigerant path 2c are not specifically limited.

  When the heat exchanger 2 is viewed from the flow direction of the EGR gas, that is, when viewed from the viewpoint of FIG. 1 (A), the internal refrigerant passage 2c extends from the center of the heat exchanger 2 to the outer peripheral cooling passage 4. It is provided radially.

  The heat exchanger 1 includes a housing member 3 that forms an outer peripheral refrigerant passage 4 between which a refrigerant that exchanges heat with the heat exchanger 2 flows. The housing member 3 is a stainless steel (SUS) tube material. The housing member 3 can also use other materials such as aluminum. The housing member 3 includes flange portions 3a at both ends thereof. Inside each flange part 3a, the edge part of the heat exchange body 2 is located, and both are integrated by shrink fitting. A sealing agent is provided between the flange portion 3a and the heat exchange body 2, and a water stop treatment is performed. Referring to FIGS. 2 and 3, the outer peripheral refrigerant passage 4 is formed between the inner peripheral surface of the housing member 3 and the outer peripheral wall 2 d of the heat exchanger 2. That is, the refrigerant directly touches the heat exchanger 2. It can also be set as the structure which isolate | separates the heat exchanger 2 and a refrigerant | coolant. For example, it is a structure provided with an inner pipe. In addition, since the refrigerant directly touches the heat exchanger 2 as described above, it is desirable that the heat exchanger 2 has high density.

  The housing member 3 includes a refrigerant inlet 3b1 for introducing a refrigerant into the outer peripheral refrigerant passage 4 and a refrigerant outlet 3b2 for discharging the refrigerant in the outer peripheral refrigerant passage 4. Although any refrigerant may be used, in the present embodiment, cooling water is used. The outer peripheral refrigerant passage 4 communicates with each internal refrigerant passage 2c. For this reason, in the heat exchanger 1, a refrigerant | coolant can also be introduce | transduced also to the center part vicinity of the heat exchanger 2, and heat can also be taken from the center part vicinity. As a result, the heat exchanger 1 has improved cooling performance of the fluid to be cooled compared to the case where the internal refrigerant passage 2c is not provided. Further, since the contact area between the heat exchanger 2 and the refrigerant is increased by providing the internal refrigerant passage 2c, the cooling performance of the fluid to be cooled is also improved in this respect.

  When the internal refrigerant passage 2c is provided radially from the center of the heat exchanger 2 toward the outer periphery cooling passage 4, the distance from any point in the heat exchanger 2 to the nearest refrigerant is made as uniform as possible. It is desirable to do. Thereby, each part of the heat exchange body 2 is cooled uniformly. By uniformly cooling each part of the heat exchanger 2, particularly in the radial direction, the EGR gas cooled uniformly is discharged. Moreover, when the heat exchanger 2 is cooled uniformly, the temperature gradient in the radial direction is relaxed, and the thermal stress acting on the heat exchanger 2 is reduced. Thereby, the crack etc. of the heat exchange body 2 are suppressed.

(Second Embodiment)
Next, the heat exchanger 20 of the second embodiment will be described with reference to FIG. FIG. 4A is an explanatory view of the heat exchanger 20 of the second embodiment viewed from the inlet side of the fluid to be cooled, and FIG. 4B is a cross-sectional view taken along the line CC in FIG. is there. The difference between the heat exchanger 20 of the second embodiment and the heat exchanger 1 of the first embodiment is that the landfill 22b and the internal portion of the first embodiment are replaced with the landfill 2b and the internal refrigerant passage 2c in the first embodiment. This is a point provided with a refrigerant passage 22c. Moreover, in 2nd Embodiment, the partition plate 3c is provided in the housing member 3, and the outer peripheral part refrigerant path 4 is divided | segmented into the high voltage | pressure part 4a and the low voltage | pressure part 4b by this partition plate 3c. The refrigerant inlet 3b1 is provided on the high pressure part 4a side, and the refrigerant outlet 3b2 is provided on the low pressure part 4b side. As a result, the upstream side where the refrigerant is introduced has a high pressure, and the downstream side where the refrigerant is discharged has a low pressure.

  The landfill portion 22b is formed by embedding a material in the tubular passage 22a at a desired portion after the heat exchanger 22 is extruded as in the landfill portion 2b in the first embodiment. As is apparent from FIG. 4A, the landfill portion 22b is provided across the heat exchanger 22. More specifically, the heat exchanger 22 is traversed so as to connect the high pressure part 4a and the low pressure part 4b. Such a landfill portion 22b is provided with internal refrigerant passages 22c1 and 22c2 that cross the heat exchanger 22 and connect between the outer peripheral refrigerant passages 4, more specifically, the high pressure portion 4a and the low pressure portion 4b. Yes. The internal refrigerant passages 22c1 and 22c2 are provided by a drill path. The angle and number of the internal refrigerant passages can be set as appropriate. Since the internal refrigerant passages 22c1 and 22c2 pass through the central portion of the heat exchanger 22, the central portion of the heat exchanger 22 can be cooled. Moreover, since the high pressure part 4a and the low pressure part 4b are provided and both are connected by the internal refrigerant passages 22c1 and 22c2, the flow rate of the refrigerant can be increased. Thereby, cooling efficiency can be improved. Moreover, since the contact area between the heat exchanger 22 and the refrigerant increases as in the first embodiment, the cooling efficiency is improved in this respect as well.

  In the example shown in FIGS. 4A and 4B, the internal refrigerant passages 22c1 and 22c2 connect the high-pressure part 4a and the low-pressure part 4b at the diameter part of the heat exchanger 22, but at other parts. It is also possible to connect the two.

  In addition, about the component which is common in 1st Embodiment, the same reference number is attached | subjected in drawing and the detailed description is abbreviate | omitted.

  The above embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to these, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims.

DESCRIPTION OF SYMBOLS 1, 20 Heat exchanger 2, 22 Heat exchanger 2a, 22a Tubular passage 2b Landfill part 2c Internal refrigerant path 2d Outer wall 3 Housing member 3a Flange part 3b1 Refrigerant inlet 3b2 Refrigerant outlet 4 Outer part refrigerant path

Claims (3)

A heat exchanger in which a plurality of tubular passages through which a fluid to be cooled passes are formed;
A housing member that is disposed around the heat exchange body and forms an outer peripheral refrigerant passage through which a refrigerant that exchanges heat with the heat exchange body flows between the heat exchange body;
An internal refrigerant passage that communicates with the outer peripheral refrigerant passage and guides the refrigerant in the outer peripheral refrigerant passage to the inside of the heat exchanger;
A heat exchanger.   The internal refrigerant passage is provided radially from the center of the heat exchange body toward the outer peripheral cooling passage when the heat exchange body is viewed from the flow direction of the fluid to be cooled. The heat exchanger as described in.   The heat exchanger according to claim 1 or 2, wherein the internal refrigerant passage crosses the heat exchanger and connects between the outer peripheral refrigerant passages.

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