WO2017094366A1

WO2017094366A1 - Fin for heat exchanger

Info

Publication number: WO2017094366A1
Application number: PCT/JP2016/080560
Authority: WO
Inventors: 圭久原
Original assignee: 三桜工業株式会社
Priority date: 2015-12-04
Filing date: 2016-10-14
Publication date: 2017-06-08
Also published as: JP2017101904A

Abstract

A fin according to an embodiment of the invention is provided with: a gas flow passage R having a rectangular wave-shaped cross-section; and cut and raised sections 42 formed by cutting and raising a wall section into the gas flow passage R, the wall section including an upper wall, side walls, and a bottom wall. The cut and raised sections 42 each include: a bend line 43 tilted relative to the flow direction D of exhaust gas; and linear cuts 44 extending downstream in the flow direction D from the upstream end 43a of the bend line 43 in the flow direction D and reaching the downstream end 43b. The cut and raised sections 42 are each formed by bending a region 42a inward along the bend line 43, the region 42a being surrounded by the bend line 43 and the linear cuts 44. The cut and raised sections 42 are arranged at a plurality of positions located along the flow direction D. The bend lines 43 of the cut and raised sections 42 are tilted to the same side relative to the flow direction D when viewed from the inside of the gas flow passage R.

Description

Heat exchanger fins

The present invention relates to a heat exchanger fin having a plurality of gas flow paths.

Japanese Patent No. 4683111 describes an EGR (Exhaust Gas Recirculation) gas cooler as a kind of heat exchanger. This EGR gas cooler is mounted on an exhaust gas recirculation system that includes a vehicle engine, an exhaust gas recirculation pipe that circulates exhaust gas from the engine, and an EGR valve provided in the exhaust gas recirculation pipe. The EGR gas cooler is disposed between the exhaust side of the engine and the EGR valve. The EGR gas cooler performs heat exchange between the exhaust gas from the engine and the cooling water to cool the exhaust gas.

The EGR gas cooler described in the above-mentioned publication includes a rectangular box-shaped tube constituting an exhaust gas flow path and an inner fin formed in a rectangular wave shape inside the tube. The exhaust gas flow path is formed by the side wall of the inner fin, the upper wall or the bottom wall of the inner fin, and the tube plates positioned above and below the inner fin. A plurality of exhaust gas flow paths are arranged along the juxtaposed direction of the top wall, the side wall, and the bottom wall.

In the above-described inner fin, the side wall includes one side wall and the other side wall arranged so as to be shifted in the parallel arrangement direction with respect to the one side wall. When the inside of the inner fin is viewed from the upper surface side, one side wall and the other side wall are alternately arranged in a rectangular wave shape. Further, on the downstream side in the flow direction of one side wall and the upstream side in the flow direction on the other side wall, a cut-and-raised portion formed by cutting and raising the bottom wall in a triangular shape is arranged. This cut-and-raised portion is provided to generate a vertical vortex inside the inner fin.

Japanese Patent No. 3729136 describes an EGR gas cooler. The EGR gas cooler is provided with a tube and an inner fin having the same functions as described above. The inner fin is also formed in a rectangular wave shape by the upper wall, the side wall, and the bottom wall. In the inner fin, a hole portion that communicates the inside and the outside is formed in the side wall, and a cut-and-raised portion that is cut and raised in a triangular shape is formed in the bottom wall of the inner fin. The holes and the cut-and-raised portions are alternately arranged along the flow direction of the exhaust gas. Further, the fold line of the cut and raised portion is inclined with respect to the flow direction. One cut and raised portion and the other cut and raised portion adjacent to the one cut and raised portion in the flow direction are inclined to the opposite sides.

Japanese Patent No. 4683111 Japanese Patent No. 3729136

In the inner fin described in Japanese Patent No. 4683111, cut-and-raised portions are arranged on the downstream side in the flow direction of one side wall and the upstream side in the flow direction on the other side wall. Therefore, even if a vertical vortex is generated at the cut-and-raised portion, the vertical vortex is disturbed and disappeared by the side wall on the downstream side of the cut-and-raised portion. Therefore, there is a problem that the pressure loss inside the flow path is large and the generated vortex disappears immediately, so that the vortex cannot be maintained along the flow direction.

In the inner fin described in Japanese Patent No. 3729136, one cut and raised portion and another cut and raised portion adjacent to the one raised portion in the flow direction are inclined to the opposite sides. Therefore, even if a vertical vortex is generated at one cut-and-raised portion, the vertical vortex is canceled by another cut-and-raised portion located downstream of the one cut-and-raised portion. Therefore, as described above, there is a problem that the pressure loss inside the flow path is large and the generated vortex disappears immediately, and there is a problem that the vortex cannot be maintained along the flow direction.

As described above, in the inner fin described in each of the above-mentioned publications, the vortex cannot be maintained along the flow direction, so that the flow velocity in the vicinity of the wall portion of the gas channel cannot be increased. Therefore, there arises a problem that soot is easily deposited on the wall portion of the gas flow path, and there is room for improvement in terms of the heat transfer coefficient for the gas.

Accordingly, an object of one aspect of the present invention is to provide a fin for a heat exchanger that can maintain a vortex along a flow direction.

A fin for a heat exchanger according to one aspect of the present invention includes a gas flow path having a rectangular wave shape formed by a continuous upper wall, a side wall, and a bottom wall, and a wall portion including the upper wall, the side wall, and the bottom wall. And a heat exchanger fin including a cut and raised portion cut and raised inside the gas flow path. The cut-and-raised part is a bend line inclined with respect to the gas flow direction at the wall part, and extends from the upstream end part in the flow direction of the bend line to the downstream side in the flow direction and at the downstream end part in the flow direction of the bend line. A score line extending to The cut-and-raised part is formed by folding a region surrounded by the fold line and the cut line to the inside of the gas flow path along the fold line. The cut and raised portions are arranged at a plurality of positions along the flow direction. Each fold line of the plurality of cut and raised portions is inclined to the same side with respect to the flow direction when viewed from the inside of the gas flow path.

According to the heat exchanger fin according to one aspect of the present invention, the cut-and-raised portion includes a fold line inclined with respect to the gas flow direction, and a flow direction from the upstream end portion to the downstream end portion of the fold line. And a cut line extending downstream of the. The cut-and-raised part is formed by folding the region surrounded by the fold line and the cut line inward along the fold line. Therefore, in the cut-and-raised part, the bent region is directed to the upstream side in the flow direction, and the gas flowing into the cut-and-raised part from the upstream side flows obliquely in the inclination direction of the folding line. Therefore, since the gas flow direction is converted into the inclination direction of the fold line, a spiral flow can be generated in the gas flow path by turning the gas in the gas flow path. The cut and raised portions are arranged at a plurality of positions along the flow direction, and the fold lines of the plurality of cut and raised portions are inclined to the same side. Therefore, the generated spiral flow can be maintained along the flow direction. That is, the plurality of cut-and-raised portions function as guides for the generated spiral flow, and can flow gas while maintaining the spiral flow in the flow direction. Therefore, the vortex can be maintained along the flow direction, and the flow velocity in the vicinity of the wall portion of the gas channel can be increased. Therefore, it is possible to suppress soot accumulation in the vicinity of the wall portion of the gas flow path, and to improve the heat transfer coefficient for the gas.

Further, the inclination angle of the fold line with respect to the flow direction may be 30 ° or more and 60 ° or less. In this case, since the spiral flow can be generated more efficiently at the cut and raised portion, the vortex can be more reliably maintained along the flow direction.

The distance between the downstream end in the flow direction of the fold line and the wall closest to the downstream end is the distance between the upstream end in the flow direction of the fold line and the side wall closest to the upstream end. It may be less than the distance. In this way, by reducing the distance between the downstream end portion and the wall portion of the folding line of the cut and raised portion with respect to the distance between the upstream end portion and the wall portion, the flow path on the downstream side of the cut and raised portion. Can be made narrower. Therefore, since the pressure of the gas flowing on the downstream side of the cut and raised portion can be increased, a stronger spiral flow can be efficiently generated. Therefore, since the helical flow in the gas flow path can be strengthened, soot accumulation can be more reliably suppressed and the heat transfer rate can be further increased.

The cut-and-raised part includes a first cut-and-raised part cut and raised from the side wall, and a second cut and raised part cut and raised from the upper wall or the bottom wall. The cut and raised portions are arranged at a plurality of positions along the flow direction, and the distance between the first cut and raised portion and another first cut and raised portion adjacent to the flow direction is L, the first cut and raised portion. And the distance between the second cut-and-raised part adjacent in the flow direction may be 0.1L ≦ e ≦ 0.4L. In this case, since the first cut-and-raised portion and the second cut-and-raised portion can be arranged at positions that easily function as a guide for the spiral flow, the spiral flow can be further strengthened. Therefore, since the flow rate can be further increased, soot accumulation can be more reliably suppressed and the heat transfer rate can be further increased.

The cut-and-raised part includes a first cut-and-raised part cut and raised from the side wall, and a second cut and raised part cut and raised from the upper wall or the bottom wall. The cut and raised portions are arranged at a plurality of positions along the flow direction, and the distance between the first cut and raised portion and another first cut and raised portion adjacent to the flow direction is L, the first cut and raised portion. And 0.6L ≦ e ≦ 0.9L may be satisfied, where e is the distance from the second cut and raised portion adjacent in the flow direction. Also in this case, since the first cut-and-raised part and the second cut-and-raised part can be arranged at positions where they can easily serve as spiral flow guides, the same effects as described above can be obtained.

According to one aspect of the present invention, the vortex can be maintained along the flow direction.

It is a schematic diagram which shows an example of the exhaust-gas recirculation system provided with the fin of the EGR cooler which concerns on 1st Embodiment. It is a disassembled perspective view which shows the EGR cooler of FIG. It is a disassembled perspective view which shows the heat exchanger tube and fin in the EGR cooler of FIG. It is a perspective view which shows the fin of the EGR cooler of FIG. (A) is a top view which shows the fin of FIG. (B) is a side view of one gas flow path in the fin of FIG. (A) is a top view which shows the cut and raised part of the fin of FIG. (B) is sectional drawing which shows the state which cut and raised the part by the surface orthogonal to a bottom wall. It is a figure which shows the cross section when the fin of FIG. 4 is cut | disconnected by the surface orthogonal to a flow direction, and the flow of gas. It is a perspective view which shows the fin of the EGR cooler of 2nd Embodiment. (A) is a top view which shows the fin of FIG. (B) is a side view of one gas flow path in the fin of FIG. It is a perspective view which shows the fin of the EGR cooler of 3rd Embodiment. (A) is a top view which shows the fin of FIG. (B) is a side view of one gas flow path in the fin of FIG.

Hereinafter, an embodiment of a heat exchanger fin according to one aspect of the present invention will be described with reference to the drawings. In each figure, the same code | symbol is attached | subjected to the element which is the same or it corresponds, and the overlapping description is abbreviate | omitted.

(First embodiment)
FIG. 1 is a schematic diagram illustrating an exhaust gas recirculation system 1 including fins of an EGR cooler 10 that is a heat exchanger according to the present embodiment. The exhaust gas recirculation system 1 includes an automobile engine 2, an EGR valve 3, an exhaust circulation path 4, and an EGR cooler 10. The exhaust gas recirculation system 1 takes out a part of the exhaust gas G after being burned in the engine 2, and causes the engine 2 to inhale the part of the taken out exhaust gas G again. The exhaust gas recirculation system 1 is intended to reduce nitrogen oxides in the exhaust gas G, for example.

The engine 2, the EGR valve 3, and the EGR cooler 10 are connected to each other via the exhaust circuit 4. Exhaust gas G is released from the engine 2, and a part of the exhaust gas G circulates in the exhaust circulation path 4. The exhaust gas G flowing through the exhaust circulation path 4 enters the EGR cooler 10. In the exhaust gas recirculation system 1, for example, a method is adopted in which the temperature of the exhaust gas G is lowered and then mixed with the fresh air F, and the EGR cooler 10 is provided to lower the temperature of the exhaust gas G. The EGR valve 3 is provided to adjust the amount of exhaust gas G returned to the engine 2.

The EGR cooler 10 includes a gas introduction part 10a for introducing the exhaust gas G, a gas discharge part 10b for discharging the cooled exhaust gas G, a cooling water introduction part 10c for introducing the cooling water W into the EGR cooler 10, and a cooling A cooling water discharge portion 10d for discharging the water W from the EGR cooler 10. The exhaust gas G introduced into the EGR cooler 10 from the gas introduction part 10 a is cooled in the EGR cooler 10. On the other hand, the cooling water W introduced from the cooling water introduction part 10 c cools the exhaust gas G by exchanging heat with the exhaust gas G in the EGR cooler 10. Thereafter, the cooling water W is discharged out of the EGR cooler 10 from the cooling water discharge portion 10d.

2, the EGR cooler 10 includes a plurality of heat transfer tubes 20 through which the exhaust gas G is circulated. The heat transfer tubes 20 have a rectangular flat box shape extending in the flow direction D of the exhaust gas G, and are stacked along the stacking direction S. The heat transfer tube 20 extends in the flow direction D and the width direction H. Further, the stacking direction S, the flow direction D, and the width direction H are, for example, orthogonal to each other. In the example shown in FIG. 2, five heat transfer tubes 20 are stacked.

In addition to the heat transfer tube 20 described above, the EGR cooler 10 includes a first diffuser 11 that constitutes a gas introduction part 10a, a second diffuser 12 that constitutes a gas discharge part 10b, and one side in the stacking direction S of the heat transfer pipes 20 A first outer case 13 disposed on the second side, a second outer case 14 positioned on the other side in the stacking direction S of the heat transfer tubes 20, and a first fixing for fixing the first diffuser 11 to the exhaust circuit 4 on the engine 2 side. A tool 15, a second fixing part 16 for fixing the second diffuser 12 to the exhaust gas circulation path 4 on the EGR valve 3 side, a cooling water introduction pipe 17 for introducing the cooling water W into the EGR cooler 10, and the cooling water W And a cooling water outlet pipe 18 for discharging from the EGR cooler 10.

As the material of the first diffuser 11, the second diffuser 12, the first outer case 13, and the second outer case 14, for example, stainless steel is used. Thereby, the corrosion resistance and heat resistance of the 1st diffuser 11, the 2nd diffuser 12, the 1st outer case 13, and the 2nd outer case 14 are ensured. Moreover, the 1st diffuser 11, the 2nd diffuser 12, the 1st outer case 13, and the 2nd outer case 14 are joined by nickel brazing or welding, for example.

The first diffuser 11 is provided on the upstream side (engine 2 side) in the flow direction D of the stacked heat transfer tubes 20, and distributes the exhaust gas G flowing from the engine 2 through the exhaust circulation path 4 to each heat transfer tube 20. To do. The first diffuser 11 includes a rectangular frame portion 11a that houses one end of the stacked heat transfer tubes 20 in the flow direction D therein, and an annular protrusion 11b that is positioned upstream of the flow direction D of the frame portion 11a. It is equipped with. The frame portion 11a is joined to the first outer case 13 and the second outer case 14 in a state in which one end in the flow direction D of the plurality of stacked heat transfer tubes 20 is accommodated.

Also, the annular protrusion 11b is provided to fit the first fixing tool 15 that fixes the EGR cooler 10 to the exhaust circuit 4. The first fixture 15 has a rhombus shape. The first fixture 15 is provided at the center thereof with a circular hole 15a into which the annular protrusion 11b is fitted, a pair of insertion holes 15b provided on both sides of the hole 15a and through which a bolt is inserted, It has.

In the EGR cooler 10, for example, in a state where the annular protrusion 11b is fitted in the hole 15a of the first fixture 15, each of the two bolts is inserted into the insertion hole 15b. The EGR cooler 10 is connected to the exhaust circulation path 4 on the engine 2 side by joining the first fixing member 15 to the flange portion of the exhaust circulation path 4 and bolts and nuts by the two bolts.

The second diffuser 12 includes a frame portion 12a similar to the frame portion 11a of the first diffuser 11, and an annular protrusion 12b protruding in the direction orthogonal to the flow direction D from the back of the frame portion 12a. The frame portion 12a is joined to the first outer case 13 and the second outer case 14 in a state in which the other end in the flow direction D in the plurality of stacked heat transfer tubes 20 is accommodated.

The annular protrusion 12b of the second diffuser 12 is provided to fit the second fixing portion 16 that fixes the EGR cooler 10 to the exhaust circuit 4. The second fixing part 16 has the same shape and function as the first fixing tool 15. The 2nd fixing | fixed part 16 is provided with the hole 16a located in the center of the 2nd fixing | fixed part 16, and the insertion hole 16b located in the both sides of the hole 16a. In the EGR cooler 10, each of the two bolts is inserted into the insertion hole 16b in a state where the annular protrusion 12b is fitted in the hole 16a. The EGR cooler 10 is connected to the exhaust circulation path 4 on the EGR valve 3 side by joining the second fixing part 16 to the flange part of the exhaust circulation path 4 and a bolt and nut by the two bolts.

The first outer case 13 has a rectangular flat surface 13a extending in the flow direction D and the width direction H. The first outer case 13 covers the heat transfer tube 20 from one side in the stacking direction S and is joined to the first diffuser 11 and the second diffuser 12 in a state of covering the heat transfer tube 20.

The first outer case 13 includes a plate-like protrusion 13b that protrudes in the stacking direction S at both ends in the width direction H of the flat surface 13a, and a plurality of protrusions that are located on the flat surface 13a and to which the protrusion 20a of the heat transfer tube 20 is joined. Part 13c and a pair of protrusions 13d for rectifying the cooling water W, which are located downstream in the flow direction D of the plurality of protrusions 13c. The protrusion 20b of the heat transfer tube 20 is also provided to rectify the cooling water W. The first outer case 13 holds the first diffuser 11 and the second diffuser 12 with protrusions 13 b at both ends in the width direction H.

The second outer case 14 covers the heat transfer tube 20 from the other side in the stacking direction S (the lower side in FIG. 2) and is joined to the first diffuser 11 and the second diffuser 12 in a state of covering the heat transfer tube 20. The second outer case 14 includes a rectangular flat surface 14a extending in the flow direction D and the width direction H, and a plate-shaped protrusion 14b protruding in the stacking direction S from both ends of the flat surface 14a in the width direction H. .

The length (height) of the projecting portion 14b in the stacking direction S is longer than the length of the projecting portion 13b of the first outer case 13, and the projecting portion 14b is provided on one of the two projecting portions 14b. A pair of penetrating through holes 14c are formed. One through hole 14 c is provided at each of two positions along the flow direction D. A cooling water introduction pipe 17 is fitted in the through hole 14 c on the upstream side in the flow direction D, and a cooling water outlet pipe 18 is fitted in the through hole 14 c on the downstream side in the flow direction D. The cooling water introduction pipe 10 and the through hole 14c constitute a cooling water introduction part 10c, and the cooling water outlet pipe 18 and the through hole 14c constitute a cooling water discharge part 10d.

The second outer case 14 covers the heat transfer pipe 20 with the cooling water introduction pipe 17 and the cooling water outlet pipe 18 fitted in the through holes 14c, and the first diffuser 11, the second diffuser 12, and the first outer case. 13 and the second outer case 14 are joined. Thereby, the flow path of the cooling water W is formed inside the EGR cooler 10. At this time, the cooling water W is introduced from the cooling water introduction pipe 17 into the second outer case 14 and circulates in the second outer case 14 in the same direction as the flow direction D. 2 The battery is discharged out of the outer case 14.

FIG. 3 is an exploded perspective view showing one heat transfer tube 20 in an exploded manner. As shown in FIG. 3, the heat transfer tube 20 includes a rectangular upper plate 21 and a lower plate 22 joined to the upper plate 21 in the stacking direction S. A fin 30 having a gas flow path R (see FIG. 4) for the exhaust gas G is disposed between the upper plate 21 and the lower plate 22. The fin 30 is a heat exchanger fin according to the present embodiment.

At both ends in the width direction H of the upper plate 21, plate-like protrusions 21 a that protrude in the stacking direction S are provided, and at both ends in the width direction H of the lower plate 22, plate-like protrusions 22 a are provided. It has been. The upper plate 21 and the lower plate 22 are joined by joining the projecting

portions

21a and 22a together. In the state where the upper plate 21 and the lower plate 22 are joined, one end and the other end of the heat transfer tube 20 in the flow direction D are open. The exhaust gas G flows into and out of the fin 30 from the opened portion.

FIG. 4 is a perspective view in which a part of the fin 30 is cut out. As shown in FIG. 4, the fin 30 has a rectangular wave shape in which unevenness is continuous in a direction (width direction H) orthogonal to the flow direction D and the stacking direction S. The fin 30 is manufactured, for example, by bending a single stainless steel plate. In the following description, one side in the stacking direction S (upper side of the sheet of FIG. 4) is up, and the other side of the stacking direction S (lower side of the page of FIG. 4) is down. However, these directions are merely for convenience of explanation and do not limit the scope of the present invention.

The fin 30 includes an upper wall 31 extending in the flow direction D, a side wall 32 bent at a right angle from the upper wall 31, and a bottom wall 33 bent at a right angle from the side wall 32 and extending parallel to the upper wall 31. The fin 30 has a plurality of gas flow paths R that are formed in a rectangular wave shape by the cross-sectional shape of the upper wall 31, the side wall 32, and the bottom wall 33 being continuous.

The upper plate 21 is in contact with the upper surface of the upper wall 31 and the lower plate 22 is in contact with the lower surface of the bottom wall 33. Two types of gas flow paths R exist inside the fin 30. The gas flow path R includes a gas flow path R1 formed by the pair of side walls 32, the bottom wall 33, and the upper plate 21, and a gas flow path R2 formed by the pair of side walls 32, the upper wall 31, and the lower plate 22. And. The gas flow paths R1 are provided by the number of the bottom walls 33 arranged in the width direction H, and the gas flow paths R2 are provided by the number of the upper walls 31 arranged in the width direction H. The gas flow path R1 and the gas flow path R2 each extend linearly in the flow direction D. Here, in the present embodiment, the width direction H coincides with the juxtaposed direction of the gas flow path R1 and the gas flow path R2, that is, the juxtaposed direction of the top wall 31, the side wall 32, and the bottom wall 33.

5 (a) is a plan view of the gas flow path R, and FIG. 5 (b) is a side view of one gas flow path R. As shown in FIGS. 4 and 5, the fin 30 has a plurality of cut-and-raised portions 40 cut and raised from the wall portion 35 including the upper wall 31, the side wall 32, and the bottom wall 33 to the inside of the gas flow path R. . The cut and raised portion 40 includes a first cut and raised portion 41 cut and raised from the side wall 32, and a second cut and raised portion 42 cut and raised from the upper wall 31 or the bottom wall 33.

The first cut-and-raised part 41 and the second cut-and-raised part 42 have a rectangular shape, for example, and are arranged at equal intervals in the flow direction D. The first cut-and-raised part 41 faces and intersects with the first cut-and-raised part 41 cut and raised from the other side wall 32 adjacent in the width direction H.

The first cut and raised portion 41 and the second cut and raised portion 42 are inclined to the same side with respect to the flow direction D when viewed from the inside of the gas flow path R. Specifically, the second cut and raised portion 42 is inclined counterclockwise with respect to the flow direction D when viewed from the inside of the gas flow path R1. The first cut and raised portion 41 is also inclined counterclockwise with respect to the flow direction D. Further, the second cut and raised portion 42 is inclined clockwise with respect to the flow direction D when viewed from the inside of the gas flow path R2. The first cut and raised portion 41 is also inclined clockwise with respect to the flow direction D.

There are two types of first cut-and-raised parts 41, one cut and raised on the gas flow path R2 side and one cut and raised on the gas flow path R1 side. Further, the first cut and raised portions 41 cut and raised on the gas flow path R2 side and the first cut and raised portions 41 cut and raised on the gas flow path R1 side are alternately arranged along the flow direction D. Yes.

The second cut-and-raised part 42 cut and raised from the upper wall 31 is cut and raised in a direction (downward) away from the upper plate 21 located above it. The second cut-and-raised portion 42 cut and raised from the bottom wall 33 is cut and raised in a direction (upward) away from the lower plate 22 located below the second cut-and-raised portion 42. The second cut and raised portions 42 cut and raised from the upper wall 31 and the second cut and raised portions 42 cut and raised from the bottom wall 33 are alternately arranged along the flow direction D.

In the present embodiment, the number of the first cut-and-raised portions 41 and the second cut-and-raised portions 42 arranged in one gas flow path R is the same in the plurality of gas flow paths R. The gas channel R1 and the other gas channel R1 adjacent in the width direction H have the same arrangement mode of the first cut-and-raised portion 41 and the second cut-and-raised portion 42. Further, the first cut-and-raised portion 41 and the second cut-and-raised portion 42 are arranged so as to be aligned in the width direction H. That is, the positions of the first cut-and-raised part 41 and the second cut-and-raised part 42 in the flow direction D coincide with each other among the plurality of gas flow paths R1. The same applies to the gas flow path R2.

As shown in FIG. 5A, in the gas flow path R1, the distance between the first cut and raised portion 41 cut and raised from the side wall 32 and the first cut and raised portion 41 adjacent to the flow direction D is L, Further, if the distance between the first cut and raised portion 41 and the second cut and raised portion 42 (second cut and raised portion 42 cut and raised from the bottom wall 33) adjacent to the flow direction D is e, 0.1 L <= E <= 0.4L is satisfy | filled. Further, it is more preferable to satisfy 0.2L ≦ e ≦ 0.3L, and it is more preferable that e = 0.25L. The same applies to the gas flow path R2.

Next, the detailed configuration of the second cut-and-raised part 42 will be described with reference to FIGS. 6 (a) and 6 (b). FIG. 6A is a plan view of the second cut and raised portion 42 cut and raised from the bottom wall 33. FIG. 6B is a cross-sectional view of the second cut and raised portion 42 cut in the direction perpendicular to the bottom wall 33.

Hereinafter, the second cut and raised portion 42 cut and raised from the bottom wall 33 will be described as an example. In addition, about the structure of the 2nd cut and raised part 42 cut and raised from the upper wall 31, and the 1st cut and raised part 41 cut and raised from the side wall 32, it is 2nd of FIG. 6 (a) and FIG.6 (b). Since it is the same as the structure of the cut-and-raised part 42, detailed description is abbreviate | omitted.

As shown in FIG. 6A, the second cut-and-raised part 42 includes a fold line 43 that is inclined with respect to the flow direction D, and an upstream end 43a in the flow direction D of the fold line 43 in the flow direction D. And a cut line 44 extending to the downstream side and extending to the downstream end 43b. The fold line 43 extends linearly in a direction inclined with respect to the flow direction D.

The cut line 44 includes a first straight line portion 44a extending from the upstream end 43a of the fold line 43 at a right angle to the fold line 43, and a fold line 43 extending from the downstream end in the flow direction D of the first straight line 44a. A second straight portion 44b extending in parallel and the same length as the fold line 43, and a third straight portion 44c extending from the downstream end in the flow direction D of the second straight portion 44b toward the downstream end 43b. Contains.

Thus, the cut line 44 has a rectangular shape including the first straight portion 44a, the second straight portion 44b, and the third straight portion 44c. Therefore, the second cut-and-raised part 42 is formed by bending a rectangular region 42 a surrounded by the fold line 43 and the cut line 44 inside the gas flow path R <b> 1 along the fold line 43.

Here, when the inclination angle of the fold line 43 with respect to the flow direction D is α (°), α preferably satisfies 30 ≦ α ≦ 60, more preferably satisfies 40 ≦ α ≦ 50, and α More preferably, = 45. In the present embodiment, α that is the inclination angle has the same value in the plurality of first cut-and-raised portions 41 and the second cut-and-raised portions 42.

6A shows an example in which the fold line 43 of the second cut-and-raised part 42 is inclined counterclockwise (left side) with respect to the flow direction D, but the fold line 43 is in the flow direction. It may be inclined clockwise (right side) with respect to D. In this case, the fold line 43 of the other second cut and raised portion 42 and the fold line 43 of the first cut and raised portion 41 are also tilted clockwise.

The distance between the downstream end 43b in the flow direction D of the fold line 43 and the side wall 32 facing the downstream end 43b is a, the upstream end 43a in the flow direction D of the fold line 43, and the upstream end. When the distance from the side wall 32 facing 43a is b, a ≦ b is satisfied. Further, assuming that the distance between the side wall 32 and another side wall 32 adjacent in the width direction H is B, the relationship between a, b and B is, for example, 0.05B ≦ a ≦ 0.25B and 0.25B. ≦ b ≦ 0.50B, 0.05B ≦ a ≦ 0.20B, and 0.25B ≦ b ≦ 0.45B are preferably satisfied, 0.05B ≦ a ≦ 0.15B, and 0. More preferably, 25B ≦ b ≦ 0.40B is satisfied. In the example shown in FIG. 6A of this embodiment, a = 0.10B and b = 0.36B are satisfied.

Thus, the distance between the downstream end 43b of the fold line 43 and the side wall 32 is preferably equal to or less than the distance between the upstream end 43a of the fold line 43 and the side wall 32 (a ≦ b). Further, as shown in FIG. 6B, when the bending angle of the second raised portion 42 with respect to the bottom wall 33 is β (°), it is preferable that 30 ≦ β ≦ 150 is satisfied, and 30 ≦ β ≦ 90. It is more preferable that

The function and effect of the fin 30 configured as described above will be described. In the fin 30, the second cut-and-raised part 42 has a fold line 43 inclined with respect to the flow direction D of the exhaust gas G, and a flow direction D from the upstream end 43 a to the downstream end 43 b of the fold line 43. , And a cut line 44 extending downstream. The second cut-and-raised part 42 is formed by bending an area 42 a surrounded by the fold line 43 and the cut line 44 inward along the fold line 43. The same applies to the first cut and raised portion 41.

Therefore, as shown in FIG. 7, in the second cut and raised portion 42 cut and raised from the bottom wall 33, the bent region 42 a faces the upstream side in the flow direction D. The exhaust gas G that has flowed into the second cut-and-raised part 42 from the upstream side flows in the direction away from the bottom wall 33 (upward) and in the direction of inclination of the fold line 43. On the other hand, in the second cut-and-raised portion 42 cut and raised from the upper wall 31, the exhaust gas G flows in the direction away from the upper wall 31 (downward) and in the direction of inclination of the fold line 43. In the first cut-and-raised portion 41 cut and raised from the side wall 32, the exhaust gas G flows in the direction away from the side wall 32 and in the inclination direction of the fold line 43.

Therefore, since the direction in which the exhaust gas G flows is converted into the inclination direction of the fold line 43, a spiral flow can be generated in the gas flow path R. The first cut-and-raised part 41 and the second cut-and-raised part 42 are arranged at a plurality of positions along the flow direction D, and the plurality of first cut-and-raised parts 41 and the second cut and raised parts 42 are bent. Line 43 is inclined to the same side. Therefore, the generated spiral flow can be maintained along the flow direction D.

That is, the plurality of first cut-and-raised portions 41 and second cut-and-raised portions 42 function as guides for the generated spiral flow, and can flow the exhaust gas G while maintaining the spiral flow in the flow direction D. Therefore, the vortex of the exhaust gas G can be maintained along the flow direction D, and the flow velocity in the vicinity of the wall portion 35 of the gas flow path R can be increased. Therefore, it is possible to suppress soot accumulation in the vicinity of the wall portion 35 of the gas flow path R, and to improve the heat transfer coefficient with respect to the exhaust gas G.

Further, as shown in FIG. 6A, the inclination angle of the fold line 43 with respect to the flow direction D is preferably 30 ° or more and 60 ° or less. In this case, the spiral flow can be more efficiently generated by the first cut and raised portion 41 and the second cut and raised portion 42. Therefore, the vortex can be more reliably maintained along the flow direction D.

Further, the distance between the downstream end 43b in the flow direction D of the fold line 43 and the wall 35 closest to the downstream end 43b is equal to the upstream end 43a in the flow direction D of the fold line 43 and the upstream side. It is below the distance with the wall part 35 nearest to the edge part 43a (a <= b). Thus, the first cut-and-raised portion 41 and the second cut-and-raised portion are obtained by shortening the distance between the downstream end portion 43b and the wall portion 35 with respect to the distance between the upstream end portion 43a and the wall portion 35. The flow path on the downstream side of 42 can be made narrower.

Therefore, since the pressure of the exhaust gas G flowing on the downstream side of the first cut and raised portion 41 and the second cut and raised portion 42 can be increased, a more powerful spiral flow can be efficiently generated. Therefore, since the spiral flow in the gas flow path R can be strengthened, soot accumulation can be more reliably suppressed and the heat transfer rate can be further increased.

Further, as shown in FIG. 5A, the first cut and raised portion 41 and the second cut and raised portion 42 are arranged at a plurality of positions along the flow direction D. The distance between the first cut and raised portion 41 and the other first cut and raised portion 41 adjacent to the flow direction D is L, and the first cut and raised portion 41 and the second cut and raised portion 42 adjacent to the flow direction D are When the distance is e, 0.1L ≦ e ≦ 0.4L is satisfied. Therefore, the first cut-and-raised part 41 and the second cut-and-raised part 42 can be arranged at positions that easily function as guides for the spiral flow, so that the spiral flow can be further strengthened. Therefore, since the flow rate can be further increased, soot accumulation can be more reliably suppressed and the heat transfer rate can be further increased.

(Second Embodiment)
Next, the fin 50 of 2nd Embodiment is demonstrated, referring FIG.8, FIG.9 (a) and FIG.9 (b). The fin 50 of the second embodiment is different from the first embodiment in the arrangement of the first cut-and-raised part 51 and the arrangement of the second cut-and-raised part 52 formed therein. The configurations of the first cut and raised portion 51 and the second cut and raised portion 52 themselves are the same as the configurations of the first cut and raised portion 41 and the second cut and raised portion 42 of the first embodiment. In the following description, the description which overlaps with 1st Embodiment is abbreviate | omitted.

As shown in FIG. 8, FIG. 9A and FIG. 9B, the first cut-and-raised portion 51 and the second cut-and-raised portion 52 are arranged at equal intervals in the flow direction D, for example. The first cut and raised portions 51 cut and raised from the side wall 32 to the gas flow path R1 and the first cut and raised portions 51 cut and raised from the side wall 32 to the gas flow path R2 are alternately arranged along the flow direction D. Arranged at intervals.

Further, in the gas flow path R1, the distance between the first cut and raised portion 51 cut and raised from the side wall 32 and the first cut and raised portion 51 adjacent in the flow direction D is L, and the first cut and raised portion 51 is If the distance from the second cut and raised portion 52 adjacent to the flow direction D is e, 0.6L ≦ e ≦ 0.9L is satisfied. Further, 0.7L ≦ e ≦ 0.8L is more preferable, and e = 0.75L is even more preferable. The same applies to the gas flow path R2.

As described above, in the fin 50 according to the second embodiment, the direction in which the exhaust gas G flows is converted by the fin 50 into the inclination direction of the fold line 43 as in the first embodiment, so that the spiral is formed in the gas flow paths R1 and R2. A flow can be generated. Further, the first cut-and-raised portion 51 and the second cut-and-raised portion 52 are arranged at a plurality of positions along the flow direction D, and the plurality of first cut-and-raised portions 51 and the second cut and raised portion 52 are the same. Inclined to the side.

Therefore, the generated spiral flow can be maintained along the flow direction D. Furthermore, in the second embodiment, the distance between the first cut-and-raised portion 51 and the other first cut-and-raised portion 51 adjacent to the flow direction D is L, and the first cut-and-raised portion 51 is adjacent to the flow direction D. When the distance from the second cut and raised portion 52 is e, 0.6L ≦ e ≦ 0.9L is satisfied. Therefore, the first cut-and-raised part 51 and the second cut-and-raised part 52 can be arranged at positions where they can easily function as a spiral flow guide, so that the same effect as in the first embodiment can be obtained.

(Third embodiment)
Next, the fin 60 according to the third embodiment will be described with reference to FIGS. 10, 11 (a), and 11 (b). The fin 60 of the third embodiment is different from the first embodiment and the second embodiment in the arrangement of the first cut-and-raised portion 61 and the arrangement of the second cut-and-raised portion 62 therein.

As shown in FIG. 10, FIG. 11 (a), and FIG. 11 (b), the number of second raised portions 62 arranged in each of the gas flow path R1 and the gas flow path R2 is the same as that of the first embodiment. More than in the second embodiment. The number of the second cut and raised portions 62 is twice the number of the second cut and raised portions 42 and the second cut and raised portions 52. Accordingly, the interval between the second cut and raised portions 62 arranged along the flow direction D is ½ of the interval between the second cut and raised portions 42 and the second cut and raised portions 52.

The first cut and raised portions 61 cut and raised from the side wall 32 to the gas flow path R1 side and the first cut and raised portions 61 cut and raised from the side wall 32 to the gas flow path R2 side are alternately arranged along the flow direction D. Is arranged. The first cut-and-raised portion 61 is disposed between one second cut-and-raised portion 62 and another second cut-and-raised portion 62 adjacent to the second cut and raised portion 62 in the flow direction D. .

Further, as shown in FIG. 11B, a first cut and raised portion 61 cut and raised from the side wall 32 to the gas flow path R1 side, and a first cut and raised from the side wall 32 to the gas flow path R2 side. The raising portions 61 are inclined to the opposite sides with respect to the flow direction D. However, the first cut-and-raised portion 61 and the second cut-and-raised portion 62 cut and raised inside the gas flow paths R1 and R2 are on the same side with respect to the flow direction D when viewed from the inside of the gas flow path R. Inclined.

As shown in FIG. 11 (b), in the gas flow path R1, the distance between one first cut and raised portion 61A cut and raised from the side wall 32 and the first cut and raised portion 61B adjacent in the flow direction D is set as follows. If the distance between the first cut-and-raised part 61A and the second cut-and-raised part 62A adjacent to the flow direction D is e2, then 0.1L ≦ e2 ≦ 0.4L is satisfied. Further, 0.2L ≦ e2 ≦ 0.3L is more preferable, and e2 = 0.25L is more preferable. On the other hand, when the distance between the first cut and raised portion 61A and the second cut and raised portion 62B adjacent to the downstream side of the second cut and raised portion 62A is e1, 0.6L ≦ e1 ≦ 0.9L is satisfied. . Further, 0.7L ≦ e1 ≦ 0.8L is more preferable, and e1 = 0.75L is even more preferable. The same applies to the gas flow path R2.

As described above, in the fin 60 according to the third embodiment, since the direction in which the exhaust gas G flows is converted into the inclined direction as described above, a spiral flow can be generated in the gas flow paths R1 and R2. The plurality of first cut-and-raised parts 61 and second cut-and-raised parts 62 cut and raised inside the gas flow paths R1 and R2 are in the flow direction D when viewed from the inside of the gas flow paths R1 and R2. Are inclined to the same side.

Therefore, since the generated spiral flow can be maintained along the flow direction D, the same effects as those of the above-described embodiments can be obtained. Further, in the third embodiment, the distance between the first cut and raised portion 61A and the other first cut and raised portion 61B adjacent to the flow direction D is L, and the first cut and raised portion 61A is adjacent to the flow direction D. When the distance from the second cut and raised portion 62A is e2, 0.1L ≦ e2 ≦ 0.4L is satisfied.

In addition, when the distance between the first cut and raised portion 61A and the second cut and raised portion 62B adjacent to the downstream side of the second cut and raised portion 62A is e1, 0.6L ≦ e1 ≦ 0.9L is satisfied. ing. Therefore, the first cut-and-raised portion 61 and the second cut-and-raised portion 62 are arranged at positions that easily function as a guide for the spiral flow, and the first cut-and-raised portion 61 and the first cut-and-raised portion 61 and the second Since the number of the two cut-and-raised portions 62 is large, the spiral flow can be further strengthened. Therefore, the flow rate can be further increased to increase the heat transfer rate, and soot accumulation can be further reliably suppressed.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and can be modified without departing from the gist described in each claim or applied to other embodiments. It may be what you did. That is, each part constituting the fin for the EGR cooler can be appropriately changed without changing the gist.

In the above-described embodiment, the example in which the first cut-and-raised portion 41 and the second cut-and-raised portion 42 are arranged at equal intervals in the flow direction D has been described. However, the cut-and-raised portions are not arranged at equal intervals. Also good. For example, as it goes to the downstream side in the flow direction D, the arrangement interval of the cut and raised portions may be gradually narrowed or widened.

In the above-described embodiment, the example in which the first cut-and-raised portion 41 and the second cut-and-raised portion 42 have a rectangular shape has been described. The curved shape such as an ellipse can be appropriately changed. That is, the cut line 44 shown in FIG. 6A only needs to extend from the upstream end 43a to the downstream side in the flow direction D and to the downstream end 43b, and the shape of the cut line 44 is appropriately set. It can be changed.

Further, in the above-described embodiment, the value of α, which is the inclination angle of the first cut-and-raised portion 41 and the second cut-and-raised portion 42 with respect to the flow direction D, is the plurality of first cut-and-raised portions 41 and the second cut and raised portions 42. The example in which the values are the same as each other has been described. However, the value of α may not be the same value in the plurality of first cut and raised portions. For example, the value of α can be gradually increased or decreased toward the downstream side in the flow direction D. The same applies to the value of β which is the bending angle of the cut and raised portion. As described above, the values of α and β, and further the values of a, b, and B described above can be changed as appropriate depending on the product specifications and required ability.

In the above-described embodiment, as shown in FIG. 3, an example is described in which the fin 30 having the gas flow path R of the exhaust gas G is disposed between the upper plate 21 and the lower plate 22 in the heat transfer tube 20. did. Here, the type and number of fins arranged in the heat transfer tube 20 can be changed as appropriate. For example, a plurality of fins having different numbers of cut-and-raised portions and different arrangement forms (the values of α and β described above are different) may be arranged along the flow direction D.

In the above-described embodiment, the example in which the EGR cooler 10 is arranged in the exhaust gas recirculation system 1 has been described. However, in the present invention, the configuration of the EGR cooler is not limited to the above example, and can be changed as appropriate. Furthermore, the configuration of the exhaust gas recirculation system is not limited to the configuration of the exhaust gas recirculation system 1 and can be changed as appropriate.

In the above-described embodiment, the example in which the heat exchanger is an EGR cooler has been described. However, the present invention can also be applied to other automotive heat exchangers such as exhaust system parts other than EGR coolers, exhaust heat recovery devices, exhaust heat exchangers, superchargers, or oil coolers.

DESCRIPTION OF SYMBOLS 1 ... Exhaust gas recirculation system, 2 ... Engine, 3 ... EGR valve, 4 ... Exhaust circulation path, 10 ... EGR cooler (heat exchanger), 10a ... Gas introduction part, 10b ... Gas discharge part, 10c ... Cooling water introduction Part, 10d ... cooling water discharge part, 11 ... first diffuser, 11a ... frame part, 11b ... annular protrusion, 12 ... second diffuser, 12a ... frame part, 12b ... annular protrusion, 13 ... first outer case, 13a ... Plane, 13b ... Projection, 13c, 13d ... Projection, 14 ... Second outer case, 14a ... Plane, 14b ... Projection, 14c ... Through hole, 15 ... First fixture, 15a ... Hole, 15b ... Insertion hole, 16 ... Second fixing part, 16a ... Hole part, 16b ... Insertion hole, 17 ... Cooling water introduction pipe, 18 ... Cooling water outlet pipe, 20 ... Heat transfer pipe, 20a, 20b ... Projection, 21 ... Upper plate , 21a ... protruding portion 22 ... Lower plate, 22a ... Projection part, 30, 50, 60 ... Fin (heat exchanger fin), 31 ... Upper wall, 32 ... Side wall, 33 ... Bottom wall, 35 ... Wall part, 40 ... Cut-and-raised part, 41 , 51, 61, 61A, 61B ... first cut and raised portion, 42, 52, 62, 62A, 62B ... second cut and raised portion, 42a ... region, 43 ... fold line, 43a ... upstream end, 43b ... downstream Side end portion 44 ... cut line, 44a ... first straight portion 44b ... second straight portion 44c ... third straight portion D ... flow direction, F ... fresh air, G ... exhaust gas, H ... width direction, R, R1, R2 ... gas flow path, S ... stacking direction, W ... cooling water.

Claims

A gas flow path whose cross section is formed in a rectangular wave shape by continuous upper wall, side wall and bottom wall;
A heat exchanger fin comprising a cut and raised portion cut and raised from the wall portion including the upper wall, the side wall, and the bottom wall to the inside of the gas flow path,
The cut-and-raised portion extends from the upstream end of the fold line in the flow direction to the downstream side of the flow direction and the fold line of the fold line. A score line extending to the downstream end in the flow direction,
The cut-and-raised part is formed by folding a region surrounded by the fold line and the cut line to the inside of the gas flow path along the fold line,
The cut and raised parts are arranged at a plurality of positions along the flow direction,
Each fold line of the plurality of cut and raised portions is inclined to the same side with respect to the flow direction when viewed from the inside of the gas flow path.
Heat exchanger fins.
The inclination angle of the fold line with respect to the flow direction is not less than 30 ° and not more than 60 °.
The heat exchanger fin according to claim 1.
The distance between the downstream end of the fold line in the flow direction and the wall portion closest to the downstream end is from the upstream end and the upstream end of the fold line in the flow direction. Less than or equal to the distance to the nearest side wall,
The heat exchanger fin according to claim 1 or 2.
The cut and raised portion includes a first cut and raised portion cut and raised from the side wall, and a second cut and raised portion cut and raised from the upper wall or the bottom wall.
The first cut-and-raised part and the second cut-and-raised part are arranged at a plurality of positions along the flow direction,
The distance between the first cut-and-raised portion and the other first cut-and-raised portion adjacent to the flow direction is L,
When the distance between the first cut and raised portion and the second cut and raised portion adjacent to the flow direction is e,
0.1L ≦ e ≦ 0.4L,
The heat exchanger fin according to any one of claims 1 to 3, wherein:
The cut and raised portion includes a first cut and raised portion cut and raised from the side wall, and a second cut and raised portion cut and raised from the upper wall or the bottom wall.
The first cut-and-raised part and the second cut-and-raised part are arranged at a plurality of positions along the flow direction,
The distance between the first cut-and-raised portion and the other first cut-and-raised portion adjacent to the flow direction is L,
When the distance between the first cut and raised portion and the second cut and raised portion adjacent to the flow direction is e,
0.6L ≦ e ≦ 0.9L,
The heat exchanger fin according to any one of claims 1 to 4, wherein: