JP2009091948A - EGR cooler - Google Patents

Abstract

Even when the cooling water inlet and the cooling water discharge port cannot be arranged at ideal positions in the EGR cooler, the cooling water can flow evenly inside the shell, and local boiling is prevented. As a result, the tube is prevented from cracking.
Cooling water is provided in an EGR cooler including a hollow shell having a cooling water introduction port and a cooling water discharge port, and a plurality of tubes arranged inside the shell and through which EGR gas passes. An adapter member 320 that is attached to the introduction port 319 and introduces cooling water into the shell 310 is provided. The adapter member 320 extends from the inside of the adapter member 320 into the shell 310, and the inside of the shell is formed from the cooling water introduction port 319. A guide plate 325 for adjusting the inflow direction of the cooling water introduced into the is disposed.
[Selection] Figure 2

Description

  The present invention relates to an EGR cooler, and more particularly to an EGR cooler including a hollow shell having a cooling water inlet and a cooling water outlet, and a plurality of tubes that are arranged inside the shell and through which EGR gas passes.

  Conventionally, an EGR cooler is configured to include a hollow shell having a cooling water inlet and a cooling water outlet, and a plurality of tubes that are arranged inside the shell and through which EGR gas passes. In such an EGR cooler, a cooling water introduction pipe is installed in a vertical direction from the upper and lower surfaces or the left and right surfaces of the shell so as to introduce the cooling water into the shell. The cooling water in the shell flows from the cooling water introduction port toward the cooling water discharge port, between the tubes and between the shells and the tubes, and cools the EGR gas flowing into the tubes.

In such an EGR cooler, various devices have been devised so that cooling water can smoothly flow between the tubes and between the shell and the tubes so that heat exchange can be performed smoothly.
In Patent Document 1, dowels are formed to maintain the clearance between the tubes and to prevent tube cracking due to vibration, and the flow of cooling water is adjusted by adjusting the arrangement / shape of the dowels and the clearance between the tubes and the shell. What has been improved is described.

  Further, in Patent Document 2, a guide member extending along the longitudinal direction of the shell is disposed at the center position of the shell vertical cross section of the EGR cooler, and the cooling water supplied into the shell is supplied to the shell by the guide member. It is guided in the outer peripheral direction of the vertical section, forms a flow in the form of a vortex or swirl, and flows in the whole range from the center side to the outer periphery side. It is described that the place where it stays, that is, the so-called stagnation part, can be prevented as much as possible by the guide member.

  Patent Document 3 has a plurality of EGR pipes through which EGR gas flows, and an outer case that houses the EGR pipe and through which cooling water flows, and the outer case has a substantially circular cross section at the intermediate portion. Both of the end portions are larger in diameter than the intermediate portion, and an inlet pipe for cooling water is provided at the end part on the inlet side of the EGR gas, and an outlet pipe is provided at the end part on the outlet side of the EGR gas. Is provided in a tangential direction with respect to the outer case, so that the flow can be made uniform at the cooling water inlet portion and local overheating can be prevented from occurring.

And in patent document 4, except the area | region which tends to produce a stagnation in each part of the plane of a flat tube, many bulging parts for distribution | circulation alienation are spaced apart from each other only in the circulation area | region where the circulation of cooling water is comparatively quick. What is described as protruding from the outer surface side of the flat tube is described.
JP 2003-090693 A JP 2003-83174 A JP 2005-273512 A JP 2004-177060 A

  By the way, in such an EGR cooler, it is ideal that the cooling water flows evenly in the shell. FIG. 12 is a schematic diagram showing an example of the configuration of such an EGR cooler. In this EGR cooler 210, a cooling water inlet 214 and a cooling water outlet 215 are arranged on the diagonal line of the shell 211 in which the tube 216 is built. That is, the cooling water introduction port 214 is disposed at one end (right end in this example) of the lower side surface 212 of the shell 211, and the cooling water discharge port 215 is disposed at the other end (left end in this example) of the upper side surface 213. Cooling water is introduced from the bottom and discharged from the top so that the cooling water flows along the path A.

  However, in recent years, restrictions on the engine layout have increased, and it has become difficult to ideally arrange the cooling water inlet and the cooling water outlet. 13 and 14 are schematic views showing an EGR cooler under layout restrictions.

  The EGR cooler 220 shown in FIG. 13 has a cooling water inlet 224 and a cooling water outlet 225 arranged on one side of the shell 221, for example, an upper side 222. In this case, the cooling water easily flows along the path B in the upper part of the shell 221, and stagnation of the cooling water is likely to occur in the region C in the lower part of the shell 221.

  Further, the EGR cooler 230 shown in FIG. 14 has a cooling water inlet 234 disposed on the lower side 232 of the shell 231, and is located on the upper side 233 of the shell 231 at a position just above the cooling water inlet 234. A cooling water discharge port 235 is arranged. In this case, the cooling water flowing in from the cooling water inlet 234 tends to flow upward along the path D as it is, and the stagnation of the cooling water is likely to occur in the region E on one side of the shell 231.

  When stagnation of cooling water occurs in the shell in this way, boiling occurs locally near the stagnation of this cooling water, the tube is exposed from the cooling water and heated to expand, and in the worst case, the tube cracks. May occur. However, the configuration adopted in the above-described conventional EGR cooler cannot be prevented.

  The present invention has been made in view of such problems, and even when the cooling water inlet and the cooling water discharge port cannot be arranged at ideal positions in the EGR cooler, the cooling water is uniformly distributed inside the shell. It is an object of the present invention to provide an EGR cooler that can be flowed, prevents local boiling, and thus prevents the tube from cracking.

In the present invention, means for effectively solving the above problems are as follows.
The invention according to claim 1 is an EGR cooler comprising a hollow shell provided with a cooling water inlet and a cooling water outlet, and a plurality of tubes disposed inside the shell and through which EGR gas passes. An adapter member that is attached to the inlet and introduces cooling water into the shell is provided. The adapter member extends from the inside of the adapter member into the shell, and is introduced into the shell from the cooling water inlet. An EGR cooler including a guide plate that adjusts the inflow direction of water.

  According to a second aspect of the present invention, in the EGR cooler according to the first aspect, two or more guide plates are arranged.

  According to a third aspect of the present invention, in the EGR cooler according to the first or second aspect, the guide plate includes a ridge portion that protrudes along the extending direction of the guide plate.

  According to a fourth aspect of the present invention, in the EGR cooler according to the first or second aspect, the guide plate includes a communication slit portion through which the cooling water can flow with the guide plate interposed therebetween along the extending direction of the guide plate. It is characterized by that.

  According to a fifth aspect of the present invention, in the EGR cooler according to the first or second aspect, the guide plate intersects the extending direction of the guide plate with a communication slit portion through which cooling water can flow with the guide plate interposed therebetween. It is characterized by providing along.

  The invention according to claim 6 is the EGR cooler according to any one of claims 1 to 5, wherein the guide plate of the adapter member is joined to the adapter body in a cantilever state.

  A seventh aspect of the present invention is the EGR cooler according to any one of the first to sixth aspects, wherein the guide plate is disposed so that a tip thereof is close to the tube.

  According to the first aspect of the present invention, since the adapter member having the guide plate is arranged at the cooling water inlet of the shell, the cooling water flowing from the adapter member is guided by the guide plate, and the corner portion of the shell. In addition, it can efficiently flow in an area where the tube is obstructed and stagnation of the cooling water easily occurs, local boiling is prevented, damage to the EGR cooler is prevented, and the performance of the EGR cooler can be maximized. In addition, since the guide plate is arranged inside the adapter member, there is no need to change the external shape of the EGR cooler, and there is no influence when the EGR cooler is mounted on the vehicle. Since the efficiency can be increased, the amount of cooling water can be reduced, and the burden on the cooling water pump can be reduced.

  According to the second aspect of the present invention, since two or more guide plates are arranged in the adapter portion, it is preferable for the stagnation portion that tends to occur when the EGR cooler is enlarged and the number of tubes is increased. Can guide cooling water.

  According to the invention of claim 3, since the guide plate is provided with the protruding strip portion along the extending direction, the cooling water is guided while being rectified by the protruding strip portion, so that the cooling water is efficiently guided to the necessary place. it can.

  According to the invention of claim 4, since the communication slit portion along the extending direction is formed in the guide plate, the amount of cooling water divided by the guide plate can be adjusted, and the guide state of the cooling water is finely adjusted. it can.

  According to the invention of claim 5, since the communication slit portion is formed in the direction intersecting the extending direction in the guide plate, the amount of cooling water divided by the guide plate can be adjusted, and the cooling water guiding state Can be finely adjusted.

  According to the invention of claim 6, when the adapter member is produced by press working, the guide plate can be formed by being joined to the adapter main body in a cantilever state, so that the trouble of joining the guide plate to the adapter main body can be saved, and the adapter member Can be easily manufactured.

  According to the seventh aspect of the present invention, since the tip of the guide plate is arranged close to the tube, the distance between the tip of the guide plate and the tube can be narrowed, and the cooling water divided by the tube guide plate It can guide you to the necessary places without mixing.

  Hereinafter, an EGR cooler according to an embodiment of the present invention will be described with reference to the drawings. 1 is a perspective view showing the appearance of an EGR cooler according to the first embodiment of the present invention, and FIG. 2 is a cross-sectional view corresponding to the line FF in FIG. 1 showing the structure of the EGR cooler shown in FIG.

  As shown in FIG. 1, the EGR cooler 300 according to this example is configured by arranging a plurality of plate-type tubes 340 through which EGR gas flows into the shell 310, and circulating cooling water through the shell 310. The EGR gas in 340 is cooled. Note that headers provided at both ends of the shell 310 and guiding the EGR gas are not shown.

  The shell 310 is a combination of two U-shaped plates 311 and 312 formed by pressing metal plates, and is joined at joints 313 and 314, and a lower side 315, an upper side 316, one side 317, and the other side 318. It is formed in the substantially square cylinder shape provided with. Then, a cooling water introduction port 319 is opened at one end in the longitudinal direction of the upper side surface 316 where the joint portion 313 of the U-shaped plates 311 and 312 is formed, and a cooling water discharge port (not shown) is opened at the other end. Cooling water flows into the shell 310 from the cooling water introduction port 319, and the cooling water subjected to heat exchange is discharged from the cooling port discharge port. In this example, an adapter member 320 is connected to the cooling water inlet 319, and a water pipe member 330 is connected to the cold water outlet.

  The tube 340 disposed in the shell 310 includes a flattened hollow member 341 and dowels 342 for disposing these hollow members 340 across a gap, and is arranged in parallel in the vertical direction.

  The water distribution pipe member 330 includes a cylindrical portion 331, a shell side flange portion 332 formed at one end of the cylindrical portion 331 and connected to the shell 310, and a drain side flange formed at the other end of the cylindrical portion 331 and connected to a drain pipe. Part 333.

  Next, the adapter member 320 will be described. 3 shows an adapter member of the EGR cooler shown in FIG. 1, (a) is a side view, (b) is a bottom view, and FIG. 4 shows an adapter member of the EGR cooler shown in FIG. (A) is a perspective view, (b) is a front view.

  The adapter member 320 includes a curved cylindrical portion 321 that is curved with an introduction side portion 321a into which cooling water is introduced and a shell side portion 321b that is connected to the shell 310, and an introduction side portion of the curved cylindrical portion 321. A water supply flange portion 322 is formed around a hole portion 323 provided in the port 321a and connected to a water supply pipe into which cooling water is introduced. Further, the other end of the shell side portion 321 b is provided with a connection end portion 324 that connects the adapter member 320 to the periphery of the cooling water inlet 319 of the shell 310.

  And in this example, the guide plate 325 is arrange | positioned inside the shell side part 321b of the curved cylinder part 321. FIG. The guide plate 325 is inserted from the inside of the adapter member 320 through the cooling water introduction port 319 and extends into the shell 310, and the tip 325 a is close to the upper end 340 a of the tube 340 disposed in the vicinity of the cooling water introduction port 319. Arranged. In this example, the adapter member 320 is formed by integrally casting the curved cylinder portion 321, the water supply flange portion 322, the connection end portion 324, and the guide plate 325.

  Further, the arrangement angle and shape of the guide plate 325 are adjusted so that the cooling water flows evenly between the tubes 340 arranged in the shell 310. In other words, the guide plate 325 has a distal end portion 325 a bent at an angle θ from the extending direction of the base portion 325 b, and has a flow path G that is slightly inclined with respect to the upper side surface 316 from the hole 323 into the shell 310. The cooling water flowing in along the flow path is divided into two flow paths, a flow path G1 and a flow path G2. In this example, the flow path G1 is bent by the tip 325a of the guide plate 325 and the upper end 340a of the tube 340, and is bent in the direction opposite to the direction in which the water pipe member 330 is arranged in the drawing. Moreover, the flow path G2 is guided by the front-end | tip 325a of the guide plate 325, and goes to the water distribution pipe member 330 side in the figure.

  Since the EGR cooler 300 according to the present example has such a configuration, the cooling water introduced into the adapter member 320 is guided by the guide plate 325, and is obstructed by the corners of the shell 310 and the tube 340, thereby cooling water. Efficient flow also occurs in a region where stagnation is likely to occur, local boiling is prevented, damage to the EGR cooler can be prevented, and the performance of the EGR cooler can be maximized.

  The inventor analyzed the velocity distribution of the cooling water in the EGR cooler 300 described above. FIG. 5 shows the distribution of the cooling water velocity in the EGR cooler. (A) is a graph showing the analysis result of the EGR cooler of the comparative example, and (b) is a graph showing the analysis result of the EGR cooler according to this example. is there. As a comparative example, the following EGR cooler 600 was used. FIG. 6 is a cross-sectional view showing a configuration of an EGR cooler to be compared. The EGR cooler 600 has the same configuration as the EGR cooler 300 according to this example except that the adapter member 620 is not provided with a guide plate. That is, the EGR cooler 600 includes the same shell 310 as the EGR cooler 300, a water distribution pipe member 330, and a tube 340, and an adapter member 620 on which a guide plate is not disposed is disposed on the shell 310.

  As a result of the analysis, in the EGR cooler 600 of the comparative example, the flow of the cooling water is biased in one direction as shown in FIG. 5A, so that the AA cross section in FIG. 5C (region H in FIG. 6). In the EGR cooler 300 of this example, the flow is divided and the cooling water is distributed in the necessary direction by the current plate, whereas the stagnation occurs in the F-F cross section (region K in FIG. 6). Therefore, as shown in FIG.5 (b), the stagnation of the AA cross section and the FF cross section was improved, and the favorable flow velocity distribution was shown. Thereby, the effect of the guide plate was confirmed.

  According to the EGR cooler 300 according to this example, the cooling water flowing in from the adapter member 320 is guided by the guide plate 325, and in the corner of the shell 310 or the region where the tube 340 is obstructed and the cooling water is likely to stagnate. It is possible to efficiently flow, local boiling is prevented, damage to the EGR cooler 300 is prevented, and the performance of the EGR cooler 300 can be maximized. In addition, since the guide plate 325 according to the present example is disposed inside the adapter member 320, there is no need to change the external shape of the EGR cooler 300, and there is no influence when the EGR cooler is mounted on the vehicle. Since the cooling efficiency can be increased with the optimal flow, the amount of cooling water can be reduced and the burden on the cooling water pump can be reduced.

  Next, an EGR cooler 400 according to a second embodiment of the present invention will be described. FIG. 7 is a cross-sectional view corresponding to the line FF in FIG. 1 of the EGR cooler according to the second embodiment of the present invention. The EGR cooler 400 according to this example is suitable when the number of tubes 440 arranged in the shell 410 is increased and the stacking direction is increased in order to improve the performance of the EGR cooler. In this example, in order to increase the introduction amount of the cooling water, the cooling water introduction port 429 is enlarged in the tube stacking direction of the adapter member 420 and the two guide plates 425 and 426 are arranged.

  According to the EGR cooler 400 according to this example, a large amount of cooling water introduced from the enlarged cooling water introduction port 429 can be reliably diverted in the required direction by the two guide plates 425 and 426, so that a large number of tubes Cooling water can be circulated through the large-capacity shell 410 containing the 440 without any stagnation. Note that the number of guide plates can be three or more as required.

  Next, a modification of the EGR cooler of the present invention will be described. FIG. 8 is a partially cutaway front view showing the adapter member of the EGR cooler according to the third embodiment of the present invention. In this example, an adapter member 510 is disposed in an EGR cooler, and the adapter member 510 includes a curved tube portion 511, a water supply flange portion 512, a connection end portion 514, and a guide plate 515. A plurality of ridges 516 are provided so as to protrude along the extending direction of the guide plate 515. According to this example, since the guide plate 515 is provided with the ridge portion 516, the cooling water is guided while being rectified by the ridge portion 516 of the guide plate 515, and the cooling water can be efficiently guided to a necessary place.

  FIG. 9 is a partially cutaway front view showing the adapter member of the EGR cooler according to the fourth embodiment of the present invention. In this example, an adapter member 520 is disposed in an EGR cooler, and the adapter member 520 includes a curved cylinder portion 521, a water supply flange portion 522, a connection end portion 524, and a guide plate 525. A plurality of communication slit portions 526 through which cooling water can flow through the guide plate 525 are provided along the extending direction of the guide plate 525. According to this example, since the communication slit portion 526 along the extending direction is formed in the guide plate 525, the amount of cooling water divided by the guide plate 525 can be adjusted, and the guide state of the cooling water is finely adjusted. it can. Note that the number and size of the communication slit portions can be appropriately changed according to the state of the EGR cooler to be used.

  FIG. 10 is a partially cutaway front view showing the adapter member of the EGR cooler according to the fifth embodiment of the present invention. In this example, an adapter member 530 is disposed in an EGR cooler, and the adapter member 530 includes a curved cylinder portion 531, a water supply flange portion 532, a connection end portion 534, and a guide plate 535. A plurality of communication slit portions 536 through which cooling water can flow with the guide plate 535 interposed therebetween are provided in a direction orthogonal to the extending direction of the guide plate 535. According to this example, since the communication slit part 536 orthogonal to the extending direction of the guide plate 535 is formed, the amount of cooling water divided by the guide plate 535 can be adjusted, and the guide state of the cooling water can be finely adjusted. Can be adjusted. In addition, the number, size, arrangement angle, and the like of the communication slit portions can be appropriately changed according to the state of the EGR cooler to be used.

  FIG. 11 is a cross-sectional view showing an adapter member of an EGR cooler according to the sixth embodiment of the present invention. The adapter member 540 according to the present example forms a cylindrical adapter main body 541 and a guide plate 542 joined to the adapter main body 541 by sheet metal pressing, and the guide plate 542 has an adapter main body 541 at its base 542a. Are joined in a cantilevered state. According to this example, when the adapter member 540 is manufactured, the trouble of joining the guide plate 542 to the adapter main body 541 can be saved, and the adapter member 540 can be easily manufactured. In this way, joining the guide plate to the adapter main body in a cantilever manner can be applied not only when the adapter member is formed by pressing, but also when the adapter member is manufactured by casting.

  In the above example, the EGR cooler is described as an example in which a plurality of flat plate type tubes are arranged in parallel in a square cylindrical shell. However, as an EGR cooler, a plurality of heat transfer tubes are provided in a cylindrical heat exchanger cylinder. It can also be applied to a so-called shell-and-tube type in which is provided.

It is a perspective view which shows the external appearance of the EGR cooler which concerns on the 1st embodiment of this invention. It is sectional drawing equivalent to the FF line in FIG. 1 which shows the structure of the EGR cooler shown in FIG. The adapter member of the EGR cooler shown in FIG. 1 is shown, (a) is a side view, (b) is a bottom view. The adapter member of the EGR cooler shown in FIG. 1 is shown, (a) is a perspective view, (b) is a front view. FIG. 1 shows a distribution of cooling water speed of the EGR cooler shown in FIG. 1, (a) is a graph showing an analysis result of an EGR cooler to be compared, and (b) is a graph showing an analysis result of an EGR cooler according to this example. It is. It is sectional drawing which shows the structure of the EGR cooler made into the comparison object. It is sectional drawing equivalent to the GG line in FIG. 1 of the EGR cooler which concerns on the 2nd embodiment of this invention. It is a partially broken front view which shows the adapter member of the EGR cooler which concerns on the 3rd embodiment of this invention. It is a partially broken front view which shows the adapter member of the EGR cooler which concerns on the 4th embodiment of this invention. It is a partially broken front view which shows the adapter member of the EGR cooler which concerns on the 5th embodiment of this invention. It is a cross-sectional view which shows the adapter member of the EGR cooler which concerns on the 6th embodiment of this invention. It is sectional drawing which shows the flow of the cooling water in the conventional EGR cooler. It is a schematic cross section which shows the location of the stagnation of the cooling water in the conventional EGR cooler. It is a schematic cross section which shows the location of the stagnation of the cooling water in the conventional EGR cooler.

Explanation of symbols

300 EGR cooler 310 Shell 311, 312 U-shaped plate 313, 314 Joint portion 315 Lower side surface 316 Upper side surface 317 One side surface 318 Other side surface 319 Cooling water inlet 320 Adapter member 321 Curved cylindrical portion 321a Introducing side portion 321b Shell side portion 322 Water supply flange portion 323 Hole portion 324 Connection end portion 325 Guide plate 325a Tip end 325b Base portion 330 Water distribution pipe member 331 Tube portion 332 Shell side flange portion 333 Drain side flange portion 340 Tube 340a Upper end 341 Hollow member 342 Dowel 400 EGR cooler 410 Shell 420 Adapter Member 425, 426 Guide plate 429 Cooling water inlet 440 Tube 510 Adapter member 511 Curved cylinder portion 512 Water supply flange portion 514 Connection end portion 515 Guide plate 516 Convex portion 520 Adapter member 521 Curved cylinder portion 52 Water flange 524 connecting end portion 525 the guide plate 526 communicating slit 530 adapter member 531 curved tubular portions 532 communicating the water supply flange portion 534 connecting end portion 535 the guide plate 536 a slit 540 adapter member 541 adapter body 542 guide plate

Claims (7)

In an EGR cooler comprising a hollow shell having a cooling water inlet and a cooling water outlet, and a plurality of tubes arranged inside the shell and through which EGR gas passes,
An adapter member that is attached to the cooling water inlet and introduces cooling water into the shell;
The adapter member is provided with a guide plate that extends from the inside of the adapter member to the inside of the shell, and that adjusts an inflow direction of the cooling water introduced into the shell from the cooling water introduction port. .   The EGR cooler according to claim 1, wherein two or more guide plates are arranged.   3. The EGR cooler according to claim 1, wherein the guide plate includes a ridge portion that protrudes along an extending direction of the guide plate. 4.   The EGR cooler according to claim 1, wherein the guide plate includes a communication slit portion through which cooling water can flow with the guide plate interposed therebetween along an extending direction of the guide plate.   3. The EGR cooler according to claim 1, wherein the guide plate includes a communication slit portion through which cooling water can flow through the guide plate along a direction intersecting with an extending direction of the guide plate. .   6. The EGR cooler according to claim 1, wherein the guide plate of the adapter member is joined to the adapter main body in a cantilever state.   The EGR cooler according to any one of claims 1 to 6, wherein the guide plate has a tip disposed close to the tube.