JP6104107B2 - Heat exchanger - Google Patents

Description

  The present invention relates to a heat exchanger used for an EGR (Exhaust Gas Recirculation) cooler in a passage for circulating exhaust gas of an engine to an intake passage.

For example, in an EGR cooler according to Patent Document 1, a plurality of heat transfer tubes forming exhaust gas flow paths are disposed in a shell body through which cooling water flows, and high-temperature exhaust gas flowing through the heat transfer tubes. Was cooled by heat exchange with cooling water flowing outside the tube wall.
When using a heat transfer tube, a configuration is used in which a protrusion is provided in the heat transfer tube or the shape of the heat transfer tube is spiraled in order to prevent the development of the boundary layer on the exhaust gas side and promote turbulent flow to improve heat exchange performance. This increases the processing cost.

On the other hand, for example, a heat exchanger according to Patent Document 2 includes a double cylinder of a heat transfer cylinder and an outer cylinder, and heat is exchanged by providing a large number of heat transfer fins with flow holes provided on the inner and outer surfaces of the heat transfer cylinder. A two-fluid passage was formed, a gas-liquid two-phase refrigerant was passed through one flow path, and a high-temperature fluid was passed through the other flow path.
When heat transfer fins are used, it is not necessary to perform special processing or the like on the heat transfer tubes, and costs can be reduced.

JP 2007-225137 A JP 59-115983 A

  However, when heat transfer fins are used as in Patent Document 2, since the flow holes of the heat transfer fins on the high-temperature fluid side overlap, it is easy to pass through laminar flow, and turbulent flow is difficult to occur. For this reason, there is a problem that the heat exchange performance is low.

  In Patent Document 2, the opening ratio of the heat transfer fins on the refrigerant side of the gas-liquid two-phase flow is increased in the direction in which the evaporation of the refrigerant proceeds to reduce the flow velocity. This is for suppressing an increase in pressure loss due to an increase in volume, and does not promote the generation of turbulent flow by shifting the flow holes.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a heat exchanger that can obtain high heat exchange performance while suppressing processing costs.

A housing provided with a first passage through which the first fluid flows, a second passage through which the second fluid for cooling the first fluid flows, and a plurality of flow holes through which the first fluid passes are formed, and the first fluid is formed in the first passage. A plurality of perforated plates arranged at intervals in the flow direction, and a cylindrical member disposed in contact with an adjacent perforated plate and having an outer peripheral surface in close contact with the inner peripheral surface of the first passage. In the plate, the positions of the flow holes are shifted between adjacent porous plates.

  According to this invention, since the positions of the flow holes are shifted between the adjacent perforated plates, the first fluid is disturbed when passing through the flow holes, so that turbulent flow is easily generated, and heat exchange is promoted. The Therefore, it is possible to provide a heat exchanger that can obtain high heat exchange performance while suppressing the processing cost for complicating the shape of the heat transfer tube, which has been conventionally required.

It is a longitudinal cross-sectional view which shows the structure of the EGR cooler which concerns on Embodiment 1 of this invention. 1 is an external perspective view showing a configuration of an EGR cooler according to Embodiment 1. FIG. 1 is an external perspective view showing a configuration of a perforated plate of an EGR cooler according to Embodiment 1. FIG. It is a top view which shows the structure of the porous plate of the EGR cooler which concerns on Embodiment 1, and shows an example of the positional relationship of an exhaust-gas circulation hole. It is a top view which shows the structure of the porous plate of the EGR cooler which concerns on Embodiment 1, and shows another example of the positional relationship of an exhaust-gas circulation hole. 6 is an external perspective view showing a modification of the perforated plate of the EGR cooler according to Embodiment 1. FIG.

Embodiment 1 FIG.
Below, the case where the heat exchanger concerning the present invention is used as an EGR cooler in a passage which circulates engine exhaust gas to an intake passage is explained as an example.

  In the EGR cooler shown in the longitudinal sectional view of FIG. 1 and the external perspective view of FIG. 2, the inside of the cylindrical housing 1 is an exhaust gas passage 2 (first passage), and exhaust gas (first fluid) is circulated. Two water cooling passages 3 (second passages) are provided outside the housing 1 to allow cooling water (second fluid) to flow, and the housing 1 is cooled by water cooling. In the exhaust gas passage 2, porous plates 4, 5 having a large number of exhaust gas circulation holes 4 a, 5 a are installed alternately, and the porous plates 4, 5 are cooled by the housing 1. The hot exhaust gas is cooled by passing through the exhaust gas circulation holes 4 a and 5 a while being in contact with the perforated plates 4 and 5.

The perforated plates 4 and 5 are fixed inside the exhaust gas passage 2 by, for example, press fitting or insert casting. The flow direction of the cooling water in the water cooling passage 3 may be the same direction as the exhaust gas in the exhaust gas passage 2 or the opposite direction.
In FIG. 1, the number of holes is reduced in order to facilitate understanding of the positional relationship between the exhaust gas circulation holes 4a and the exhaust gas circulation holes 5a.

FIG. 3 is an external perspective view of the porous plate 4, and FIG. 4 is a plan view of the porous plate 4.
The perforated plate 4 is composed of a disc in which a large number of round exhaust gas circulation holes 4a are formed, and a cylindrical tubular spacer 4b (cylindrical member) provided on the periphery of the disc. The cylindrical spacer 4b is brought into contact with the perforated plate 5 to adjust the distance between the plates. Further, by providing the cylindrical spacer 4b, the contact area with the inner wall surface of the exhaust gas passage 2 is increased, and the cooling capacity is improved. By increasing the number of exhaust gas circulation holes 4a or increasing the opening area, it is possible to prevent exhaust gas pressure loss when passing through the EGR cooler.
The perforated plate 5 has the same structure as the perforated plate 4, and is composed of an exhaust gas flow hole 5a and a perforated plate 5b as shown in FIG.

In the EGR cooler of the present invention, the exhaust gas flow holes 4a and 5a are shifted in the exhaust gas flow direction so as to disturb the exhaust gas flow to generate a turbulent flow and promote heat exchange.
In FIG. 4, the arrangement of the exhaust gas circulation holes 4a of the perforated plate 4 and the arrangement of the exhaust gas circulation holes 5a of the perforated plate 5 are changed so that the exhaust gas circulation holes 4a and the exhaust gas circulation holes 5a do not overlap. Therefore, the exhaust gas flow holes 4a and 5a are displaced between the perforated plate 4 and the perforated plate 5 installed on the front and back thereof, thereby disturbing the exhaust gas flow and promoting the generation of the turbulent flow.

On the other hand, in FIG. 5, the arrangement of the exhaust gas circulation holes 4a of the perforated plate 4 and the arrangement of the exhaust gas circulation holes 5a of the perforated plate 5 are the same, but the installation angle of the perforated plate 4 and the perforated plate 5 is changed. Thus, the exhaust gas circulation hole 4a and the exhaust gas circulation hole 5a are shifted.
In the case of FIG. 5, it is difficult to prevent the exhaust gas circulation holes 4a and 5a from completely overlapping depending on the arrangement of the exhaust gas circulation holes 4a and 5a. However, since one kind of perforated plate can be used as the perforated plates 4 and 5, there is a merit of cost reduction.
Note that the perforated plates 4 and 5 of FIGS. 4 and 5 may be mixed and installed in the exhaust gas passage 2.

In either case of FIG. 4 or FIG. 5, high heat exchange performance can be obtained simply by installing the porous plates 4, 5 in the exhaust gas passage 2 of the housing 1. The processing cost for complicating the shape of the heat transfer tube as in the case becomes unnecessary, and the cost can be reduced.
Further, in the multi-tube heat exchanger, it is necessary to change the length of the heat transfer tube when changing the total length of the heat exchanger, but in FIGS. 4 and 5, the perforated plate 4 is used when changing the total length of the housing 1. , 5 need only be changed.

  Further, in the case of FIGS. 4 and 5, the cooling capacity can be easily adjusted according to the number of the perforated plates 4 and 5 provided in the exhaust gas passage 2. Further, the cooling efficiency can be easily adjusted according to the distance between the plates. For example, the cooling capacity and the cooling efficiency are improved by increasing the number of the perforated plates 4 and 5 to shorten the distance between the plates.

  The housing 1 and the perforated plates 4, 5 can be inserted into the exhaust gas passage 2, that is, copper, aluminum that can sufficiently conduct heat even if there is a clearance that can move with respect to the inner wall surface of the exhaust gas passage 2. It is desirable to use a material having high thermal conductivity such as. Different materials may be used for the housing 1 and the porous plates 4, 5, but the outer peripheral surfaces of the cylindrical spacers 4 b, 5 b come into contact with the inner wall surface of the exhaust gas passage 2 so that the porous plates 4, 5 can be efficiently cooled. Therefore, it is desirable to select a material having the same thermal expansion coefficient.

  As described above, according to the first embodiment, the EGR cooler includes the housing 1 provided with the exhaust gas passage 2 through which the exhaust gas flows, the water cooling passage 3 through which the cooling water for cooling the exhaust gas flows, and the exhaust gas through which the exhaust gas passes. A plurality of perforated plates 4 and 5 in which a large number of gas flow holes 4a and 4b are formed, and a plurality of perforated plates 4 and 5 are arranged in the exhaust gas passage 2 at intervals in the exhaust gas flow direction. The positions of the exhaust gas flow holes 4a and 5a are shifted between the plates 4 and 5. For this reason, when the exhaust gas passes through the exhaust gas circulation holes 4a and 5a, it is disturbed and turbulent flow is easily generated, and heat exchange is promoted. Therefore, it is not necessary to complicate the shape of the heat transfer tube as in the conventional multi-tube heat exchanger, and it is possible to provide an EGR cooler that can obtain high heat exchange performance while suppressing processing costs.

  Further, according to the first embodiment, as shown in FIG. 4, the exhaust gas circulation holes 4a and 5a between the adjacent porous plates 4 and 5 are arranged differently, so that the exhaust gas circulation holes 4a and 5a are completely formed. It is possible to enhance the effect of promoting turbulence by arranging so as not to overlap.

  Further, according to the first embodiment, as shown in FIG. 5, the exhaust gas flow holes 4a, 5a of the adjacent porous plates 4, 5 are in the same arrangement, and the porous plates 4, 5 are Since the positions of the exhaust gas circulation holes 4a and 5a are shifted by changing the installation angle, the types of perforated plates can be reduced to reduce the cost.

  Further, according to the first embodiment, the cylindrical spacers 4b and 5b are provided in the porous plates 4 and 5, and the outer peripheral surfaces of the cylindrical spacers 4b and 5b are disposed between the porous plates 4 and 5 adjacent to each other. Since it is made to adhere to the inner wall surface, the contact area between the perforated plates 4 and 5 and the housing 1 can be secured, and the cooling capacity can be increased.

In addition, a perforated plate is not limited to the perforated plates 4 and 5 shown in FIGS. Hereinafter, the modification of a perforated plate is shown in Drawing 6 (a)-(d).
The perforated plate 6 in FIG. 6 (a) is composed of a disc in which a large number of exhaust gas flow holes 6a are formed, and a cylindrical cylindrical spacer 6b provided on the periphery of the disc. In the perforated plate 4 in FIG. 3, the cylindrical spacer 4b is erected in either one direction of the disk, whereas in the perforated plate 6 in FIG. 6A, the cylindrical spacer 6b is erected in both the front and back sides of the disk. Has been established.

  The perforated plates 7 to 9 in FIGS. 6B to 6D are discs in which a large number of exhaust gas flow holes 7a to 9a are formed. The exhaust gas circulation hole is not limited to the round hole in FIG. 6B, but may be a polygon such as a quadrangle in FIG. 6C, a hexagon in FIG. 6D, or an ellipse. Further, exhaust gas circulation holes having different shapes or sizes may be mixed in one perforated plate.

When the disk-shaped perforated plates 7 to 9 are installed in the exhaust gas passage 2, a cylindrical spacer 10 as shown in FIG. 6B is sandwiched between the perforated plates in order to adjust the distance between the plates. Alternatively, the perforated plates 7 to 9 and the perforated plates 6 shown in FIG. 6A may be alternately arranged.
In FIG. 1, two types of perforated plates 4 and 5 are alternately installed in the exhaust gas passage 2, but three or more types of perforated plates may be mixed and installed.

  In addition to the above, within the scope of the invention, the invention of the present application can be modified with any component of the embodiment or omitted with any component of the embodiment.

  DESCRIPTION OF SYMBOLS 1 Housing, 2 Exhaust gas passage (1st passage), 3 Water cooling passage (2nd passage), 4-9 Porous plate, 4a-9a Exhaust gas circulation hole, 4b, 5b, 6b, 10 Cylindrical spacer (cylindrical member ).

Claims (3)

A housing provided with a first passage through which a first fluid flows and a second passage through which a second fluid for cooling the first fluid flows;
A plurality of flow holes through which the first fluid passes , and a plurality of perforated plates arranged at intervals in the direction of flow of the first fluid in the first passage ;
A cylindrical member disposed in contact with the adjacent perforated plate and having an outer peripheral surface in close contact with the inner peripheral surface of the first passage;
The perforated plate heat exchanger, characterized in that is misaligned in the communication holes between the adjacent engagement cormorants multi-hole plate.   2. The heat exchanger according to claim 1, wherein the flow holes of the adjacent porous plates have the same arrangement, and the positions of the flow holes are shifted by changing an installation angle between the porous plates. .   The heat exchanger according to claim 1, wherein the flow holes of the adjacent porous plates are arranged differently.

Images