JP2009167933A - Egr gas cooler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an EGR gas cooler certainly suppressing local boiling of cooling water at an upstream side end portion of a core element through which EGR gas passes. <P>SOLUTION: The EGR gas cooler 10 has: a plurality of the core elements 22, 23 equipped with a plurality of core tubes 24 through which the EGR of an internal combustion engine passes; a case 11 storing the core elements 22, 23, an EGR gas introducing passage introducing the EGR gas to an upstream side of the case 11; and a cooling water filling space provided in the case 11 and in which cooling water cooling the core elements flows. The plurality of the core elements 22, 23 is disposed in series in the case 11. A space portion 25 between the core elements is formed between both core elements 22, 23. An EGR branching pipe 30 in which a part of the EGR gas before heat exchange in the EGR gas introducing passage passes, and introducing the part of the EGR gas into the space portion 25 between the core elements is provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an EGR gas cooler device that exchanges heat between EGR gas from an exhaust passage of an internal combustion engine to an air supply passage with cooling water.

As a conventional EGR gas cooler device, for example, an EGR cooler disclosed in Patent Document 1 is known.
The EGR cooler is provided in parallel with a plurality of flat tubes, a case formed in a square tube shape so as to surround the outer periphery of the flat tubes, and both ends of each case, and both ends of each flat tube are provided through And a header plate formed.
A cooling water supply chamber is connected to one end portion of the peripheral wall portion of the case in the EGR cooler, a cooling water inlet pipe is connected to the cooling water supply chamber, and cooling water is connected to the other end portion of the peripheral wall portion of the case. The outlet pipe is connected.

An exhaust gas inlet pipe is connected to one open end of the case, and an exhaust gas outlet pipe is connected to the other open end of the case, so that cooling water and exhaust gas flow in parallel with each other in the case. It is supposed to be.
The cooling water supply chamber has a shape that gradually becomes wider from the distal end portion toward the proximal end portion, and is formed so that the width of the proximal end portion is substantially equal to the width of the case.
The cooling water inlet pipe is connected to the distal end portion so as to be substantially orthogonal to the flow direction of the cooling water from the distal end portion toward the proximal end portion.
Further, the cooling water inlet pipe is provided so that the connection center thereof is on the extension of the center line in the width direction of the case, and the cooling water supply chamber is formed so as to be symmetrical with respect to the extension line. Has been.

  In addition to the structure described above, a plurality of EGR cooler structures have been proposed. For example, the EGR cooler disclosed in Patent Document 2 has a thin tube formed in a cylindrical body tube by devising a flat tube structure and reducing the number of parts. An EGR cooler disclosed in Patent Document 3 is known as a housing in which a plurality of heat transfer tube groups are accommodated and a plurality of cooling medium inflow ports are provided.

According to the EGR cooler of Patent Document 1, the cooling water flows from the cooling water supply chamber while maintaining a predetermined flow rate uniformly and smoothly between the flat tubes. The inlet portion can be effectively cooled, local boiling of cooling water in the case can be suppressed, and the durability of the EGR cooler can be improved.
Moreover, in patent document 3, the local boiling of cooling water is similarly suppressed by providing a plurality of cooling medium inflow ports.
Japanese Patent Laid-Open No. 2007-154683 JP 2007-232330 A Japanese Patent Laid-Open No. 2000-234666

However, in the EGR gas cooler device disclosed in Patent Document 1 or Patent Document 3, the cooling water as the cooling water is eliminated and the local boiling of the cooling water in the case is suppressed. The upstream end portion of the core body to be passed through is structurally the part where heat exchange is most actively performed.
That is, the upstream end portion of the core body is a portion that is in contact with the hottest EGR gas, and the portion that is most actively heat-exchanged by turbulent flow in the EGR gas due to a change in the cross-sectional area of the flow path. Therefore, there remains a problem that the cooling water near the upstream end tends to boil.

  The present invention has been made in view of the above problems, and an object of the present invention is to reliably suppress local boiling of cooling water at the upstream end portion of the core body through which EGR gas passes. An EGR gas cooler is provided.

  In order to achieve the above object, the present invention introduces a core body having a plurality of core tubes through which EGR gas of an internal combustion engine passes, a case housing the core body, and introducing the EGR gas upstream of the case. An EGR gas cooler device having an EGR gas introduction passage and the cooling water filling space provided in the case and through which cooling water for cooling the core body flows, wherein a plurality of the core bodies are arranged in series in the case An EGR gas branch that is arranged in a shape and that forms an inter-core space between the core bodies and introduces the EGR gas before heat exchange in the EGR gas introduction passage into the inter-core space. A tube is provided.

According to the present invention, the EGR gas introduced into the EGR gas cooler device is not only EGR gas that passes through the plurality of core bodies in the case through the EGR gas introduction passage, but also the space between the core bodies in the case through the EGR gas branch pipe. There is EGR gas introduced into the part.
The EGR gas passing through the EGR gas branch pipe does not pass through the upstream core body, but passes through only the downstream core body.
Therefore, all the EGR gas does not pass through the upstream core body, and boiling of the cooling water in the vicinity of the upstream end portion in the upstream core body can be prevented.

  Further, in the present invention, in the above EGR gas cooler device, a tube plate that is formed by bending and divides a space portion in the case is provided, and the tube plate includes a core body housing space that houses the core tube and the tube body housing space. You may partition into a cooling water filling space.

In this case, the tube plate formed by bending partitions the space in the case into a core body housing space and a cooling water filling space.
The core tubes of the plurality of core bodies can be accommodated in the core body accommodating spaces, respectively, and the tube plate is formed by bending so that it is easy to manufacture.
In addition, when a large number of bent portions are provided, the core body accommodating spaces and the cooling water filling spaces can be alternately arranged in multiple layers, and a structure advantageous for heat exchange can be realized.

  Moreover, in this invention, in said EGR gas cooler apparatus, the said tube plate may have the recessed part space formed so that the said space part between core bodies might be expanded in the width direction.

In this case, since the tube plate has the recess space, the inter-core space portion is expanded in the width direction.
The EGR gas introduced from the EGR gas branch pipe to the inter-core space portion is expanded compared to the case where the inter-core space portion is not expanded in the width direction because the inter-core space portion is expanded in the width direction. And it becomes easy to enter in the space part between core bodies.

  Further, in the present invention, in the above EGR gas cooler apparatus, the core tube has a flat shape that can be stacked, and the core body is formed by stacking the core tubes, and is provided on at least one of the front surface and the back surface of the core tubes. A recess for forming the cooling water filling space may be formed between the stacked core tubes.

In this case, the core body is formed by stacking flat core tubes.
Between the laminated core tubes, a cooling water filling space is formed by the concave portions formed in the core tubes.
The core tube in each core body passes the EGR gas, the cooling water passes through the cooling water filling space between the core tubes, and heat exchange is performed between the EGR gas and the cooling water.
Even in the laminated type core body, it is possible to prevent boiling of the cooling water in the vicinity of the upstream end portion in the upstream core body.

  ADVANTAGE OF THE INVENTION According to this invention, the EGR gas cooler apparatus which can suppress locally the boiling of the cooling water in the upstream edge part of the core body which lets EGR gas pass can be provided.

(First embodiment)
Hereinafter, the EGR gas cooler apparatus according to the first embodiment will be described with reference to FIGS.
In this embodiment, an EGR gas cooler device provided in an EGR (exhaust gas recirculation) device in a diesel engine as an internal combustion engine will be described.
1 is a cross-sectional side view of an EGR gas cooler apparatus according to a first embodiment, FIG. 2 is a plan view of the EGR gas cooler apparatus, and FIG. 3 is an AA line view in FIG. 4 is an exploded perspective view of the EGR gas cooler device.

  As shown in FIG. 1, the EGR gas cooler device 10 of this embodiment is accommodated in a case 11 that has a rectangular tube shape, a tube plate 21 that partitions a space in the case 11, and the case 11. The upstream core body 22 and the downstream core body 23 through which the gas is branched and passed, the inter-core body space 25 formed between the core bodies 22 and 23, and the EGR gas to the upstream side of the case 11 An EGR gas pipe 19 for introducing the EGR gas, and an EGR gas branch pipe 30 for branching a part of the EGR gas in the EGR gas pipe 19 and introducing a part of the EGR gas between the core bodies 22 and 23. .

As shown in FIGS. 2 to 4, the case 11 includes a first case member 12 having a U-shaped cross section and a second case member 13 that covers a side portion of the first case member 12.
As shown in FIGS. 1, 2, and 4, the case 11 includes an upstream cover 14 that covers the upstream ends of the first case member 12 and the second case member 13, and a downstream cover 15 that covers the downstream ends. Have.
The case 11 is fixed to the engine body by two mounting brackets 34 and 35.
The upstream cover 14 includes a through hole 14 a for introducing EGR gas, and the through hole 14 a communicates with an upstream chamber 18 formed by the upstream plate member 16 and the chamber cover 17.
The chamber cover 17 is connected to the EGR gas pipe 19.
The EGR gas pipe 19 is a pipe that communicates with an exhaust passage (not shown) of the diesel engine and allows a part of the exhaust gas of the diesel engine to pass as EGR gas.
In this embodiment, the EGR gas pipe 19, the upstream chamber 18 and the upstream cover 14 constitute an EGR gas introduction passage.
The downstream cover 15 includes a through hole 15 a for leading out EGR gas, and the periphery of the through hole 15 a is held by the downstream plate member 20.
The through hole 15a communicates with an air supply passage (not shown) of the diesel engine.

In the EGR gas cooler device 10 of this embodiment, a bypass pipe 33 connected to the upstream chamber 18 is provided below the case 11.
The bypass pipe 33 is a low temperature EGR gas passage used when the temperature of the EGR gas is low.
When the temperature of the EGR gas does not reach a predetermined temperature, such as immediately after the engine is started, the EGR gas is passed only through the bypass pipe 33 without passing the EGR gas through the case 11 side.
Switching means (not shown) such as a switching valve for switching between introduction of EGR gas into the case 11 side and introduction of EGR gas into the bypass pipe 33 is installed on the downstream side of the case 11 and the bypass pipe 33. .
The switching means does not operate when the EGR gas is lower than the predetermined temperature, passes the EGR gas to the bypass pipe 33, and operates when the temperature of the EGR gas rises to a predetermined temperature or higher, and passes the EGR gas to the case 11 side. Should be provided.
Incidentally, the temperature of the EGR gas can be indirectly detected based on, for example, the engine operating state (load, rotation speed, etc.).

A tube plate 21 formed by bending is accommodated in the case 11.
The tube plate 21 partitions the space in the case 11 into two regions.
One is a core body housing space GA for housing a core tube, and the other is a cooling water filling space WA through which cooling water flows.
Since the tube plate 21 is repeatedly bent, it has a plurality of bent portions.
Since the tube plate 21 has a plurality of bent portions, the core housing space GA and the cooling water filling space WA are alternately arranged in a multilayered manner in the vertical direction, so that the core body housing space GA and the cooling water filling space are arranged. Partition the WA.

The core body accommodating space GA is a space in which the core tube 24 included in each of the core bodies 22 and 23 is accommodated, and is a space that allows passage of EGR gas.
The core tubes 24 included in the upstream core body 22 and the downstream core body 23 are accommodated in each layer of the core body accommodating space GA formed in a multilayer shape by the tube plate 21.
The core tube 24 is a heat exchange tube through which the EGR gas passes, and is formed in a wave shape as shown in FIG. 4 in order to secure a surface area for increasing the efficiency of heat exchange.
Furthermore, an inner fin (not shown) for enhancing heat exchange of EGR gas is provided inside the core tube 24.
For convenience of explanation, the core tube 24 is not shown in a wave shape in FIGS. 1 and 3.
1-3 indicate the flow of EGR gas, and the shaded region in FIG. 3 indicates a region (passage) through which EGR gas passes in the core tube 24.

An assembly of a plurality of core tubes 24 forms a core body. In this embodiment, the upstream core body 22 and the downstream core body 23 are arranged in series in the case 11.
Between the core body 22 on the upstream side and the core body 23 on the downstream side, a space portion is formed for each layer of the core body accommodation space GA, and an assembly of these space portions is used as the space portion 25 between the core bodies. And
An EGR gas passage including an upstream core body 22, a downstream core body 23, and an inter-core body space 25 is formed in the core body accommodation space GA.

On the other hand, the cooling water filling space WA is a space in which cooling water is filled and flows, and passage of EGR gas is not allowed.
The cooling water filling space WA at the upstream end and the downstream end of the tube plate 21 is sealed by seal members 36 and 37 shown in FIG.
For this reason, the core housing space GA and the cooling water filling space WA do not interfere with each other at the upstream end and the downstream end of the tube plate 21.

In this embodiment, a cooling water inlet 26 is provided near the upstream end of the second case member 13, and cooling water is supplied to the cooling water inlet 26 as shown in FIGS. 2 and 3. A tube 27 is connected.
A cooling water outlet 28 is provided near the downstream end of the second case member 13, and a cooling water discharge pipe 29 is connected to the cooling water outlet 28.
The cooling water introduced from the cooling water inlet 26 through the cooling water supply pipe 27 is passed through the cooling water filling space WA formed in a multilayer shape, and after the heat exchange with the EGR gas in the core tube 24, the cooling water is performed. Derived from the outlet 28.

The EGR gas cooler device 10 of this embodiment has an EGR gas branch pipe 30 that branches a part of the EGR gas on the upstream side of the case 11 and introduces it into the inter-core body space 25.
The upstream end of the EGR gas branch pipe 30 is connected to a branch port 19 a formed in the EGR gas pipe 19, and the downstream end of the EGR gas branch pipe 30 is an opening formed on the side of the first case member 12. 32.
The opening 32 is formed at a position corresponding to the inter-core space 25 on the side surface of the first case member 12.
At the downstream end of the EGR gas branch pipe 30, a substantially fan-shaped connection portion 31 is formed in accordance with the shape of the opening portion 32.
Therefore, the EGR gas branch pipe 30 that connects the EGR gas pipe 19 and the inter-core body space 25 passes a part of the EGR gas before heat exchange on the upstream side of the case 11 and passes the EGR gas through the inter-core body space. Part 25 is introduced.

In this embodiment, the flow path cross-sectional area of the EGR gas branch pipe 30 is passed through the EGR gas branch pipe 30 by passing an amount equal to or less than half the total EGR gas introduced into the EGR gas cooler device 10, and the remaining EGR gas is passed through the case 11. It is set to pass from the upstream side.
This is to suppress local boiling at the upstream end of the downstream core body 23.
For example, if the amount of EGR gas that passes through both core bodies 22 and 23 and the amount of EGR gas that does not pass through the upstream core body 22 is 50%, when both EGR gases merge, the upstream side of the core body 23 on the downstream side The temperature at the side end may be higher than the temperature at the upstream end in the upstream core body 22.
By reducing the ratio of the EGR gas that passes through the EGR gas branch pipe 30 compared to the EGR gas that passes through both the core bodies 22 and 23, the thermal load at the upstream end of the downstream core body 23 is reduced. be able to.

Next, the operation of the EGR gas cooler device 10 of this embodiment will be described.
When the diesel engine is in a predetermined operation state, a part of the exhaust gas of the engine is recirculated to the air supply passage. At this time, if the exhaust gas is at a high temperature, it is introduced into the EGR gas cooler device 10 as EGR gas.
The EGR gas is heat-exchanged with the cooling water in the EGR gas cooler device 10.
The EGR gas heat-exchanged by the EGR gas cooler device 10 is returned to the supply passage of the diesel engine.
The cooling water introduced from the cooling water inlet 26 passes through the cooling water filling space WA formed in a multilayer shape by the tube plate 21, and passes through the cooling water filling space WA along the longitudinal direction of the tube plate 21.
The cooling water exchanges heat with the EGR gas in the core tube 24 when passing through the cooling water filling space WA, and then is led out from the cooling water outlet 28.

In this embodiment, there are two types of EGR gas introduced into the EGR gas cooler apparatus 10.
That is, from the EGR gas pipe 19 through the upstream chamber 18, the upstream core body 22, the inter-core body space 25, and the downstream core body 23, the EGR gas led out from the case 11 and the EGR gas pipe 19 The EGR gas is discharged from the case 11 through the EGR gas branch pipe 30 and the opening 32, through the inter-core body space 25 and the downstream core body 23.

The heat exchange scheduled for the EGR gas passing through the core bodies 22 and 23 is most actively performed at the upstream end of the upstream core body 22, and the EGR gas is directed downstream.
On the other hand, the EGR gas branched in the EGR gas pipe 19 on the upstream side of the case 11 is introduced into the inter-core body space 25.
The EGR gas from the EGR gas branch pipe 30 is mixed with the EGR gas heat-exchanged by the upstream core body 22 in the inter-core body space portion 25 without passing through the upstream core body 22, and downstream. It passes through the core body 23 on the side.
Most of the heat exchange planned for both mixed EGR gases is performed when the mixed EGR gas passes through the upstream end of the downstream core body 23.
The EGR gas after the heat exchange is returned to the supply passage.

In this embodiment, the EGR gas that passes through the core bodies 22 and 23 in the case and the EGR gas that is branched into the EGR gas branch pipe 30 and passes through the core body 23 on the downstream side exist, thereby cooling the EGR gas and the cooling. A place where heat is actively exchanged with water occurs in the upstream core body and the downstream core body.
That is, as in the prior art, a place where heat exchange is actively performed between the EGR gas and the cooling water does not exist only at the upstream end portion of the upstream core body 22, but is dispersed at a plurality of locations. The

When the temperature of the EGR gas does not reach a predetermined temperature as in the cold idling operation, the switching means is not operated and the EGR gas is not passed through the case 11 side.
At this time, the EGR gas passes through the bypass pipe 33 and is returned to the supply passage of the diesel engine without performing heat exchange with the cooling water.
When the temperature of the EGR gas rises above a certain temperature, the switching means is activated and the EGR gas is passed to the case 11 side.

This embodiment has the following effects.
(1) According to the EGR gas cooler apparatus 10 according to the present invention, the EGR gas introduced into the EGR gas cooler apparatus 10 is an EGR gas branch pipe 30 in addition to the EGR gas passing through the plurality of core bodies 22 and 23 in the case 11. EGR gas that passes through only the core body 23 on the downstream side in the case 11 passes. Part of the EGR gas that passes through the EGR gas cooler device 10 does not pass through the upstream core body 22 but only through the downstream core body 23, so that all EGR gas passes through the upstream core body 22. The boiling of the cooling water in the vicinity of the upstream end of the upstream core body 22 can be suppressed.

(2) By using the tube plate 21 formed by bending, the EGR gas communicated with each space of the core body accommodating space GA only by providing the opening 32 on the side of the first case member 12 covering the side. The flow path can be formed. Thereby, it is possible to introduce a branched EGR gas without dividing the core body into two (core bodies 22 and 23) and using two EGR coolers.

(3) The place where heat exchange is actively performed between the EGR gas and the cooling water does not exist only at the upstream end portion of the upstream core body 22, but is dispersed at a plurality of locations. The total amount of EGR gas supplied to the EGR gas cooler device 10 can be increased as compared with the conventional case. If the total amount of EGR gas is not increased, the EGR gas cooler device 10 can be downsized.

(Second Embodiment)
Next, an EGR gas cooler apparatus according to a second embodiment will be described with reference to FIG.
FIG. 5 is a perspective view showing the main parts of the tube plate and the core body in the EGR gas cooler apparatus according to the second embodiment.
The EGR gas cooler apparatus of the second embodiment is common to the first embodiment except that the configuration of the tube plate is different. Therefore, the elements common to the first embodiment are denoted by the same reference numerals, and the first The description in the embodiment is incorporated and the description is omitted.

Although the case is not shown in FIG. 5 and is omitted, the tube plate 41 formed by bending partitions the space in the case 11 into a core body housing space GA and a cooling water filling space WA.
The cooling water filling space WA at the upstream end and the downstream end of the tube plate 41 is sealed with seal members 36 and 37 (FIG. 5 shows only the seal member 37 at the downstream end. )
For this reason, the core housing space GA and the cooling water filling space WA do not interfere with each other at the upstream end and the downstream end of the tube plate 41.

A large number of core tubes 24 that form the upstream and downstream core bodies 22 and 23 are disposed in the core body accommodating space GA.
A plurality of upstream core tubes 24 form an upstream core body 22, and a plurality of downstream core tubes 24 form a downstream core body 23.
Between the core body 22 on the upstream side and the core body 23 on the downstream side, an inter-core body space portion 42 is formed.
In this embodiment, a recessed space 43 formed so as to expand the inter-core space portion 42 in the width direction is formed in a portion of the tube plate 41 corresponding to the inter-core space portion 42.

The recessed space 43 is formed in the tube plate 41 so as to be recessed from the side facing the opening 32 of the first case member 12 toward the second case member 13.
Each end surface of the tube plate 41 facing the recess space 43 is closed, and cooling water does not flow into the inter-core body space portion 42 through the recess space 43.
In this embodiment, the recessed space 43 of the tube plate 41 extends the inter-core space portion 42 in the width direction, and forms an inter-core space portion 42 without a barrier in the vertical direction.
The white arrow in FIG. 5 indicates the flow of EGR gas, and the shaded area indicates the area (passage) through which EGR gas passes in the core tube 24.

  According to this embodiment, the concave space 43 formed so as to expand the inter-core space portion 42 in the width direction is formed in the portion of the tube plate 41 corresponding to the inter-core space portion 42. The EGR gas introduced from the EGR gas branch pipe 30 receives less resistance than the case where there is no recessed space 43 and easily enters the inner space (the second case member 13 side) of the inter-core body space portion 42.

(Third embodiment)
Next, an EGR gas cooler apparatus according to a third embodiment will be described with reference to FIG.
This embodiment is also an EGR gas cooler device provided in EGR in a diesel engine.
FIG. 6 is an exploded perspective view of the EGR gas cooler apparatus according to the third embodiment.
The EGR gas cooler device 50 shown in FIG. 6 has a case formed by a first case member 52 having a substantially U-shaped cross section and a second case member 53 having a flat plate shape.
In the case, a core body accommodating space for accommodating the upstream core body 57 and the downstream core body 58 is formed.
An upstream cover 54 connected to the EGR gas pipe 56 is attached to the upstream end of the case.
In this embodiment, the EGR gas pipe 56 and the upstream cover 54 constitute an EGR gas introduction passage.
A downstream cover 55 is attached to the downstream end of the case.
The upstream end of the EGR gas branch pipe 60 is connected to the branch port 54 a of the upstream cover 54, and the downstream end of the EGR gas branch pipe 60 is connected to an opening 62 formed in the first case member 52.

The core bodies 57 and 58 disposed in the case will be described. The core bodies 57 and 58 are formed by laminating a large number of flat core tubes 59.
The core tube 59 is formed with a passage through which EGR gas passes, and a rib 59a is formed along the periphery of the front surface and the back surface of the core tube 59.
That is, when the surface height of the rib 59a is used as a reference, it can be said that the concave portion 59b is formed on the front surface and the back surface of the core tube 59.
When the core tubes 59 are stacked, the ribs 59a come into contact with each other, and a space portion is formed by the upper and lower concave portions 59b facing each other between the core tubes 59 stacked.

This space portion is a cooling water filling space through which cooling water is passed, and two cutouts of ribs 59a are formed near the front surface and the back surface of one side surface of the core tube 59, respectively.
By overlapping the plurality of core tubes 59, a notch near the front surface of the lower core tube 59 and a notch near the back surface of the upper core tube 59 form an opening, and this opening introduces a cooling water filling space. A mouth 63 and an outlet 64 are formed.
In this embodiment, the opening near the upstream end is the inlet 63 and the opening near the downstream end is the outlet 64.
A cooling water filling space, an inlet 63 and a outlet 64 are formed between the core tubes 59.
6 indicate the flow of EGR gas, and the shaded region indicates a region (passage) through which EGR gas passes in the core tube 59.

Since the upstream core body 57 and the downstream core body 58 have the cooling water filling space, the first case member 52 has the cooling water inlet 66 and the cooling water corresponding to the cooling water filling space in the upstream core body 57. A water outlet 67 is provided.
Similarly, the first case member 52 has a cooling water inlet 68 and a cooling water outlet 69 corresponding to the cooling water filling space in the core body 58 on the downstream side.
That is, in this embodiment, piping for cooling water that supplies cooling water to each of the core bodies 57 and 58 is provided.

Meanwhile, an inter-core body space 61 is formed between the upstream side, the core body 57, and the downstream core body 58.
In the inter-core body space portion 61, EGR gas exchanged by the upstream core body 57 is introduced, and EGR gas introduced by the EGR gas branch pipe 60 is introduced.
The EGR gas branch pipe 60 passes a part of the EGR gas before heat exchange on the upstream side of the case, and introduces the EGR gas into the inter-core body space portion 61.
The EGR gas introduced by the EGR gas branch pipe 60 is an EGR gas that is not subjected to heat exchange because it is introduced into the EGR gas branch pipe 60 in the upstream cover 54 that is the upstream side of the case.

  According to this embodiment, even in the EGR gas cooler device 50 in which the cooling water filling space is formed by stacking the core tubes 59, the boiling of the cooling water in the vicinity of the upstream end portion of the upstream core body 57 is suppressed. The effects similar to those of the first embodiment can be obtained.

  The EGR gas cooler device according to the first to third embodiments described above shows an embodiment of the present invention, and the present invention is limited to the above-described first to third embodiments. Instead, various modifications are possible within the scope of the gist of the invention as described below.

In the first to third embodiments, the case where the internal combustion engine is a diesel engine has been described. However, the internal combustion engine may be, for example, a gasoline engine, and the type of the internal combustion engine is not particularly limited.
In the first to third embodiments, the upstream core body and the downstream core body are set to be the same, but the sizes of both core bodies may be set freely. In addition, the volume and position of the inter-core space formed between the upstream core body and the downstream core body may be set as appropriate according to the conditions of the EGR gas cooler device.
In the first embodiment, the EGR gas branch pipe is connected to the branch port of the EGR gas pipe, but the branch port may be provided in the chamber cover or the upstream cover, and the branch port connecting the EGR gas branch pipe is At least the region upstream of the upstream core body and capable of taking in the EGR gas before heat exchange, that is, the EGR gas introduction passage can be freely provided.
In the third embodiment, the inlet and outlet for communicating with the cooling water filling space are provided on one side of the core tube. For example, the inlet is provided on one side and the outlet is provided on the other side. May be. Moreover, you may vary the position of an inlet and an outlet for every core body. In addition, it is necessary to provide a cooling water inlet and outlet in the case corresponding to the positions of the inlet and outlet.
In the third embodiment, the recesses are formed on the front surface and the back surface of the core tube by providing ribs on the core tube. However, the recesses may be formed only on either the front surface or the back surface.

It is a section side view of the EGR gas cooler device concerning a 1st embodiment. It is a top view of the EGR gas cooler device concerning a 1st embodiment. It is an AA arrow directional view in FIG. It is an exploded perspective view of the EGR gas cooler device concerning a 1st embodiment. It is a perspective view which shows the principal part of the tube plate and core body in the EGR gas cooler apparatus which concerns on 2nd Embodiment. It is a disassembled perspective view of the EGR gas cooler apparatus which concerns on 3rd Embodiment.

Explanation of symbols

10, 50 EGR gas cooler device 11 Case 12, 52 First case member 13, 53 Second case member 19, 56 EGR pipe 21, 41 Tube plate 22, 57 Upstream core body 23, 58 Downstream core body 24, 59 Core tubes 25, 42, 61 Inter-core spaces 26, 66, 68 Cooling water inlet 27 Cooling water supply pipes 28, 67, 69 Cooling water outlet 29 Cooling water discharge pipes 30, 60 EGR gas branch pipes 32, 62 Opening Part 33 Bypass pipe 43 Recessed space GA Core body accommodating space WA Cooling water filling space

Claims (4)

A core body having a plurality of core tubes for passing EGR gas of an internal combustion engine, a case for housing the core body, an EGR gas introduction passage for introducing the EGR gas to the upstream side of the case, and a casing provided in the case And an EGR gas cooler device having the cooling water filling space through which cooling water for cooling the core body flows,
A plurality of the core bodies are arranged in series in the case,
A space between the core bodies is formed between the core bodies,
An EGR gas cooler apparatus comprising an EGR gas branch pipe that passes through a part of the EGR gas before heat exchange in the EGR gas introduction passage and introduces the EGR gas into a space between the core bodies. A tube plate that is formed by bending and divides a space portion in the case is provided, and the tube plate is divided into a core body accommodating space that accommodates the core tube and the cooling water filling space. The EGR gas cooler device according to claim 1. The EGR gas cooler device according to claim 1 or 2, wherein the tube plate has a recessed space formed so as to expand the space between the core bodies in the width direction. The core tube has a flat shape that can be stacked, and the core body is formed by stacking the core tubes, and at least one of a front surface and a back surface of the core tube is interposed between the stacked core tubes. The EGR gas cooler device according to claim 1, wherein a recess that forms a water filling space is formed.

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