JPH109063A - Recirculation exhaust gas cooling system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve cooling efficiency of exhaust gas without enlarging of a device by arranging a rotary heat exchanger for carrying out heat exchange by rotating a core in an exhaust circulating flow passage, leading cooling air in the core in the rotary heat exchanger, and cooling exhaust gas which passes the exhaust circulating flow passage. SOLUTION: A rotary heat exchanger 10 is interposed in an EGR device 7, and a cooled air passage 11 is arranged along an exhaust circulating flow passage 4. The rotary heat exchanger 10 is constituted by arranging a core 10B in a housing 10A so as to rotatably drive through a gear part. At the time of cooling exhaust gas, cooled air of a low temperature is led from the upstream part 11A in the cooled air passage 11 into a hole part 22B in the core 10B, and the cooled air flows out from the hole part 22A passing a bulk head 21 to cool the bulk head 21. When the cooled bulk head 21 is moved to an exhaust circulating flow passage 4 side, exhaust gas flows from an upstream part 4A in the exhaust circulating flow passage 4 into the hole part 22A, and exhaust gas is cooled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recirculating exhaust gas cooling device used for an exhaust gas recirculating device provided in a diesel engine or the like in order to reduce nitrogen oxides (NOx) contained in exhaust gas. .

[0002]

2. Description of the Related Art Conventionally, in order to reduce nitrogen oxides (NOx) contained in exhaust gas flowing out of an engine such as a diesel engine, a part of the exhaust gas is mixed into intake air of the engine. An exhaust gas recirculation device (hereinafter, referred to as an EGR device) has been proposed. This is to mix a part of the exhaust gas into the intake air of the engine, reduce the amount of oxygen in the intake air, lower the combustion temperature, and reduce nitrogen oxides (NOx).

However, when exhaust gas is mixed into the intake air of the engine, the specific heat of the intake air increases, so that the intake air amount decreases, leading to a reduction in fuel consumption and an increase in inert gas. Also. Therefore, various recirculation exhaust gas cooling devices (hereinafter, referred to as EGR coolers) have been developed and put to practical use in which the exhaust gas mixed into the intake air is cooled to eliminate the volume expansion of the intake air. I have. By using such an EGR cooler, the exhaust gas is prevented from being mixed into the intake air in a high-temperature state, and a decrease in the amount of intake air supplied into the cylinder can be suppressed.

For example, as shown in FIG. 6, such an EGR device is an exhaust gas recirculation passage 4 connecting the exhaust gas passage 2 and the intake air passage 3 of the engine 1, and a recirculation passage disposed in the exhaust gas recirculation passage 4. A circulating exhaust gas cooling device (hereinafter, referred to as an EGR cooler) 5 and an EGR valve 6 are provided.
In FIG. 6, arrows indicate the flow of exhaust gas. That is, the EGR device 7 includes the exhaust gas recirculation passage 4 that connects the exhaust gas passage 2 and the intake gas passage 3 attached to each cylinder (not shown) in the engine 1, and cools the exhaust gas in the exhaust gas recirculation passage 4. EGR cooler 5 is provided for
The EGR valve 6 is provided on the upstream side. Here, since the engine 1 is a four-cylinder engine, the exhaust passage 2 and the intake passage 3 are branched so as to correspond to each cylinder (not shown). Also,
The supply amount of exhaust gas to the engine suction side (exhaust gas recirculation amount) is controlled by the EGR valve 6.

The EGR cooler 5 includes a cooling passage 40 which forms a part of the exhaust gas recirculation passage 4,
Of the EGR cooler main body 5A and the like provided so as to cover The cooling passage 40 has a surface area as large as possible to enhance the heat radiation effect. The EGR cooler main body 5A includes an inlet 5a for introducing a refrigerant into the EGR cooler main body 5A and an EGR cooler main body 5A.
An outlet 5b for discharging the refrigerant introduced into A is provided.

In such an EGR cooler 5, a refrigerant is introduced into the EGR cooler main body 5A which covers the outside of the cooling passage 40 constituting a part of the exhaust gas recirculation passage 4, and the cooling passage 40
The exhaust gas flowing into the inside of the cooling passage 40, that is, the inside of the exhaust gas recirculation passage 4, is cooled through the wall portion 40 a. That is, heat is transmitted through the wall 40a of the cooling passage 40.

That is, conventionally, as the EGR cooler 5, a recuperate type in which exhaust gas and a refrigerant such as cooling water and cooling air are completely separated is used. On the other hand, as such a recirculation exhaust gas cooling device, for example,
No. 61 discloses a technique in which cooling fins are provided in a recirculation exhaust gas passage for heat radiation.

[0008]

However, in such a conventional EGR cooler 5, the wall 4 of the cooling passage 40 is not provided.
0a, heat is transferred from the refrigerant to the exhaust gas, so that the cooling efficiency is low.
%, The cooling efficiency can only be increased. For this reason, there is a problem that the volume expansion of the intake air cannot be sufficiently eliminated and the engine performance cannot be sufficiently improved.

[0009] Further, there is a problem that the EGR cooler 5 increases in size when exhaust gas is sufficiently cooled. On the other hand, in such a conventional EGR cooler 5, it is considered that the performance of the EGR cooler 5 is degraded due to black smoke or the like (hereinafter, referred to as "particulate") in the exhaust gas adhering in the exhaust gas recirculation passage 4. Can be Further, when the particulates in the exhaust gas are mixed into the intake air, the intake air is supplied into the cylinder, so that there is a problem that the wear of the piston is increased.

On the other hand, Japanese Patent Laid-Open Publication No.
Japanese Patent Application Laid-Open Publication No. H11-163,887 discloses a technique in which an engine equipped with an exhaust turbocharger collects particulate matter in exhaust gas. In this technique, high-pressure air stored in an air tank is blown from a downstream side to a filter in a dust collector to backwash, thereby blowing off dust accumulated in the filter.

Japanese Patent Application Laid-Open No. 1-166254 discloses an exhaust gas recirculation system for a diesel engine, in which an exhaust gas recirculation passage is provided with a particulate trap filter for trapping particulates contained in recirculated gas. E downstream of
A technology interposed with a GR cooler is disclosed, but EGR
Since the cooler and the particulate trap filter are separately provided, the size of the apparatus is increased, and the cost is increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has been made to improve the cooling efficiency of exhaust gas and to collect particulates without increasing the size of the apparatus. An object of the present invention is to provide an exhaust gas cooling device.

[0013]

According to a first aspect of the present invention, there is provided a recirculation exhaust gas cooling apparatus according to the present invention, wherein a core is rotated in an exhaust gas recirculation passage connecting an exhaust passage and an intake passage of an engine. A rotary heat exchanger that performs heat exchange is provided, and is configured to cool exhaust gas passing through the exhaust gas recirculation passage by introducing cooling air to the core of the rotary heat exchanger. It is characterized by having.

According to a second aspect of the present invention, there is provided a recirculation exhaust gas cooling apparatus according to the first aspect, wherein the core is formed of ceramic, and one end of the core is closed and the other end is formed. It is characterized in that a hole opening the portion and a hole opening at one end and closed at the other end are adjacent to each other. Claim 3
The recirculated exhaust gas cooling device according to the present invention is characterized in that, in the device according to the first aspect, the cooling air is introduced by a radiator fan of an engine or a dedicated fan. And

According to a fourth aspect of the present invention, there is provided a recirculating exhaust gas cooling apparatus according to any one of the first to third aspects, wherein the stationary portion of the rotary heat exchanger is slidably contacted with the core. A seal member is interposed at the contact portion to maintain airtightness, and the seal member is formed by coating a thin metal plate with a solid lubricant. According to a fifth aspect of the present invention, there is provided the recirculation exhaust gas cooling device according to any one of the first to third aspects, wherein the stationary portion of the rotary heat exchanger is slidably contacted with the core. A seal member is interposed to maintain airtightness, and the seal member is formed by directly spraying a solid lubricant onto the flange portion of the stationary portion.

According to a sixth aspect of the present invention, there is provided a recirculation exhaust gas cooling apparatus according to the fifth aspect, wherein the seal member is mainly made of an alloy of copper and graphite. I have.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a recirculating exhaust gas cooling apparatus according to an embodiment of the present invention. FIG. FIG. 3 is a schematic diagram showing a heat exchanger, and FIG. 3 is a schematic diagram for explaining the operation thereof. As shown in FIG. 1, the engine 1 is provided with an exhaust gas recirculation device (hereinafter, referred to as an EGR device) 7, and the EGR device 7 has a recirculation exhaust gas cooling device (hereinafter, referred to as an EGR cooler). ) Is provided. Here, the EGR cooler in the present embodiment is configured as a rotary heat exchanger (rotary heat storage heat exchanger) 10, and heat exchange between the high-temperature exhaust gas and the refrigerant is performed by the rotary heat exchanger 10. It is supposed to be. That is, in this device, a regenerator type heat exchanger that directly performs heat exchange is used as the EGR cooler.

That is, as shown in FIG. 1, the EGR device 7 includes an exhaust gas recirculation passage 4 that connects the exhaust gas passage 2 and the intake gas passage 3 of the engine 1, and the exhaust gas recirculation passage 4 is provided with a rotary heat exchange passage. (Rotary regenerative heat exchanger) 10 is provided. A cooling air passage 11 is provided along the exhaust gas recirculation passage 4. Note that, in FIG.
Arrows inside indicate the flow of the exhaust gas, and arrows inside the cooling air passage 11 indicate the flow of the cooling air.

As shown in FIG. 1, the rotary heat exchanger 10 includes a housing 10A, a core 10B provided in the housing 10A, and the like. First, the housing 10
A will be described. An exhaust gas inlet 10a and an exhaust gas outlet 10b are formed in the housing 10A. The upstream portion 4A of the exhaust gas recirculation passage 4 is connected to the exhaust gas inlet 10a, and the exhaust gas outlet 10b
Is connected to a downstream portion 4B of the exhaust gas recirculation passage 4.

The housing 10A has a cooling air inlet 10c and a cooling air outlet 10d.
The upstream side portion 11A of the cooling air passage 11 is connected to the cooling air inlet 10c, and the cooling air outlet 10d
The downstream portion 11B of the cooling air passage 11 is connected to the cooling air passage 11. Next, the core 10B will be described.

The core 10B is formed of a ceramic having excellent heat resistance in a cylindrical shape, and a plurality of holes 22 are formed in the core 10B. Each hole 22 is partitioned by a partition 21. Here, each hole 22
Is formed so that its cross-sectional shape is substantially square.
They are arranged in a grid pattern as shown in FIG. In addition,
The hole 22 thus formed has a square shape with a vertical and horizontal length of about 1 mm.

As shown in FIG. 3B, one end of the hole 22 is plugged (closed) by a plugging material 30 made of ceramic. ing. Then, one end (the upper end in FIG. 3B) is closed with the hole 22A and the other end (FIG. 3B).
(B) a hole 22B whose lower end is closed)
As shown in FIG. 3A, they are adjacent to each other. In FIGS. 3A and 3B, the number of the holes 22 is reduced because the holes 22 are shown large for easy understanding.

The partition (wall portion of the hole) 21 is formed as a porous thin wall having a large number of fine holes, and allows the passage of air but the collection of particulates of exhaust gas. I have. In addition, the thickness of the partition 21 is 0.1 mm.
It is about. The core 10B is, as shown in FIG.
Via a gear portion 20B formed on the outer peripheral surface 20A,
The drive motor 23 is driven to rotate. That is, the drive gear 24 is attached to the drive motor 23, and the drive gear 24 is attached to the cylindrical member 20.
The core 10B is driven to rotate by meshing with a gear portion 20B formed on the outer peripheral surface 20A of the core. Here, the drive motor 23 is configured to rotate at a substantially constant speed, but may be linked to the opening control of the EGR valve 6 according to the operating state of the engine.

In this manner, the core 10B rotates about the axis X in the housing 10A as shown in FIG. By the way, the housing 10A
As shown in FIGS. 1 and 2, an airtight seal is provided between a portion of the exhaust gas outlet 10b and the core 10B, and a sliding contact between the stationary portion of the rotary heat exchanger 10 and the core 10B. A seal member 12 having a D-shape is interposed in order to maintain the performance, and is sealed so that the exhaust gas in the exhaust gas recirculation passage 4 does not leak to the outside.

The exhaust gas inlet 10a and the cooling air outlet 10d of the housing 10A are connected to the core 10B.
Between the stationary part of the rotary heat exchanger 10 and the core 1
As shown in FIGS. 1 and 2, a sealing member 13 having a θ-shaped shape is interposed at the sliding contact portion where the sliding contact is made between the exhaust gas recirculation passage 4 and the exhaust gas in the exhaust gas recirculation passage 4. And the cooling gas in the cooling air passage 11 is sealed so as not to leak outside.

These seal members 12 and 13 are
It is configured by coating a thin metal plate with a solid lubricant. The exhaust gas recirculation passage 4 is for recirculating exhaust gas from the exhaust passage 2 to the intake passage 3, and has an upstream portion (a portion on the exhaust passage 2 side in FIG. 1) 4.
A is provided with an EGR valve 6, and this E
The GR valve 6 can control the flow rate of the exhaust gas from the exhaust passage 2 to the intake passage 3. In addition,
The control of the EGR valve 6 is performed according to the operating state of the engine.

The cooling air passage 11 is for introducing and flowing cooling air into and out of the rotary heat exchanger 10. A cooling fan (not shown) is provided in the upstream portion 11A to cool the cooling air. Air can be introduced into the rotary heat exchanger 10. The fan may be an engine radiator fan (not shown) or a dedicated fan (not shown).
I'm trying to use

The recirculated exhaust gas cooling device as one embodiment of the present invention is configured as described above, and the cooling of the exhaust gas by this device is performed as follows. That is,
As shown in FIGS. 1 to 3, first, low-temperature cooling air is introduced from the upstream portion 11A of the cooling air passage 11 into the hole 22B formed in the core 10B of the rotary heat exchanger 10. This cooling air passes through the partition wall 21 to form the hole 22A.
Spill out of. At this time, the partition 21 of the core 10B located in the cooling air passage 11 is cooled, and the cooling air flows out to the downstream portion 11B of the cooling air passage 11.

Next, when the partition wall 21 in the cooled core 10B moves toward the exhaust gas recirculation passage 4, the exhaust gas flows into the cooled hole 22A from the upstream portion 4A of the exhaust gas recirculation passage 4, and The exhaust gas will be cooled. Also,
The cooled exhaust gas is exhausted from the hole 22B, whereby the cooled exhaust gas can flow out to the downstream portion 4B of the exhaust gas recirculation passage 4.

That is, by passing exhaust gas and cooling air through the holes 22A and 22B, heat exchange is performed through the partition 21. That is, the partition 21 cooled by the cooling air is moved into the exhaust gas passing through the exhaust gas recirculation passage 4, and heat exchange is directly performed with the partition 21. The collection of the particulates of the exhaust gas by this device can be performed as follows.

That is, as shown in FIG. 3B, the exhaust gas containing the particulates 31 flows from the upstream portion 4A of the exhaust gas recirculation passage 4 to the core 1 of the rotary heat exchanger 10.
When flowing into the hole 22A formed in the hole 21B, the particulates 31 are formed by the partition walls 21 formed as porous thin walls.
Adheres, and the exhaust gas from which the particulates 31 have been removed flows out from the hole 22B to the downstream portion 4B of the exhaust gas recirculation passage 4 (the left side in FIG. 3B). That is,
The exhaust gas that has flowed into the hole 22A from the upstream portion 4A of the exhaust gas recirculation passage 4 has the end opposite to the hole 22A closed by the plugging material 30, so that the exhaust gas recirculation passage 4
Does not flow out to the downstream portion 4B of the
And flows out from the adjacent hole 22B to the downstream portion 4B of the exhaust gas recirculation passage 4.

Next, the partition walls 2 formed as porous thin walls
When the hole 22A, in which the particulates 31 collected by the sample 1 exist, moves toward the cooling gas passage 11, the cooling air is introduced from the hole 22B, and the introduced cooling air flows through the partition 21 into the hole. Since the particulates 31 that have entered 22B and adhered to the partition wall 21 are blown off to the downstream portion 11B of the cooling gas passage 11, it is possible to prevent the particulates 31 from flowing back into the engine 1.

According to the recirculating exhaust gas cooling apparatus of one embodiment of the present invention, it is not necessary to separately provide the EGR cooler 10 and the particulate trap for collecting the particulates 31 and the like, and the apparatus can be reduced in size. There is also an advantage that the cost can be reduced as well as the cost can be reduced. Further, a fan (not shown) is provided in the upstream portion 11A of the cooling air passage 11, and the cooling air can be introduced into the rotary heat exchanger 10 to blow off the particulates 31 attached to the partition 21. There is an advantage that the trapping ability of the particulates 31 does not decrease and the reliability of the device is high.

Further, since cooling air is introduced to cool the partition 21 of the rotary heat exchanger 10, a special air tank or the like is provided to blow off the particulates 31 attached to the partition 21. There is also an advantage that it is not necessary and the size of the device can be reduced. Further, since the cooling efficiency of the exhaust gas can be further improved (up to 96%), it is possible to prevent a reduction in the amount of intake air into the cylinder of the engine 1, thereby improving the engine performance. There is.

Further, there is an advantage that the particulates 31 can be prevented from entering the cylinders of the engine 1 and the durability of parts (for example, pistons) of the engine 1 can be improved. Further, since the core 10B is made of ceramic, there is an advantage that durability is high.

Further, since the seal members 12 and 13 are formed by coating a solid lubricant, the slidability can be improved while maintaining the airtightness, and the reliability of the apparatus can be improved.
There is an advantage that durability can be increased. In addition,
In the recirculation exhaust gas cooling device according to the present embodiment, the partition wall 21 provided in the core 10B is made of ceramic. However, the partition wall 21 is not limited to the ceramic partition and has sufficient heat resistance. What is necessary is just to be able to be comprised as a porous thin wall.

The hole 22 to which the plugging material 30 is attached
Are not limited to those described above, as long as the particulates 31 can be collected. Moreover, the plugging material 30 is not limited to a ceramic plug,
Any material may be used as long as it has heat resistance and airtightness and performs the same function. Next, a modified example of the present embodiment will be described. The recirculation exhaust gas cooling device of this modification is
As shown in FIG. 4, the configuration of the seal member is different from that of the above-described embodiment, and the rest is substantially the same as the above-described embodiment. That is, as shown in FIG. 4, the seal members 50 and 51 are formed by directly spraying a solid lubricant onto a sliding contact portion where the stationary portion of the rotary heat exchanger 10 and the core 10B are in sliding contact.

That is, the sealing member 50 is
On the downstream side 4B side of the exhaust gas recirculation passage 4 of the flange portion (sliding contact portion where the stationary portion of the rotary heat exchanger 10 and the core 10B are in sliding contact) 50a constituting the upper surface of 0A (upper side in FIG. 4),
The seal member 51 is formed by directly spraying a solid lubricant, and the seal member 51 is provided on the lower surface of the housing 10A (the lower side in FIG. 4).
Is formed by directly spraying solid lubricant on the upstream portion 4A side of the exhaust gas recirculation passage 4 of the flange portion 51a (sliding contact portion where the stationary portion of the rotary heat exchanger 10 and the core 10B are in sliding contact). Is done.

The seal members 50 and 51 prevent the exhaust gas in the exhaust gas recirculation passage 4 from leaking to the outside. In addition, the sealing members 50 and 51 are
Although both are formed to have a D-shaped shape, the present invention is not limited to this, and the seal member 1 of the present embodiment is not limited thereto.
It may be formed to have a D-shaped or θ-shaped shape as shown in 2,13.

In FIG. 4, some members are indicated by chain lines for convenience. Further, in FIG. 4, the rotary heat exchanger 10
Although it is configured to be vertically longer than that of the present embodiment, it has the same function as the rotary heat exchanger 10 of the present embodiment. Here, a mounting structure of the flange portion 50a to which the seal member 50 is welded to the housing 10A will be described with reference to FIG.

The flange portion 5 to which the sealing member 50 is welded
Oa is integrally connected to a flange portion 10D formed on the side surface of the housing 10A by a V-band coupling 52 or the like. That is, the V band coupling 52
Taking an example of the coupling by the band 52a, the band 52a
a and a V-retainer 52b formed integrally therewith. When the band 52a is tightened by a nut (not shown), the V-retainer 52b tightens the flange portion 50a and the flange portion 10D.
0a and the flange portion 10D are integrally joined.

Thus, the flange portion 50a and the core 1
0B, the exhaust gas in the exhaust gas recirculation passage 4 can be sealed so as not to leak outside. In addition, a gasket (O-ring) 53 is interposed between the flange portion 50a and the flange portion 10D, whereby the airtightness between the housing 10A and the core 10B can be further improved.

When the V-band coupling 52 is employed, a highly airtight connection can be easily and surely achieved. However, as is generally done, a gasket is sandwiched between bolts and nuts. You may make it. The seal members 50 and 51 are made of, for example, an alloy (Cu-C) of copper and graphite, an alloy (Cu-NaX) of copper and a sodium compound, and the like.

The mounting structure of the flange portion 51a to which the sealing member 51 is welded to the housing 10A has the same structure as described above. Since the modification of the present embodiment is configured as described above, it has the same effect as the recirculation exhaust gas cooling device of the present embodiment. In other words, the slidability can be improved while maintaining the airtightness, and the reliability and reliability of the device can be improved.
There is an advantage that durability can be increased.

Further, the seal members 50 and 51 are not formed as separate members, and the flange portions 50a and 50a of the housing 10A are not formed.
Since the solid lubricant 51a is formed by thermal spraying, the number of parts can be reduced. As a result, the number of assembly steps can be reduced, and the cost can be reduced. Furthermore, since the seal members 50 and 51 are formed by directly spraying a solid lubricant such as an alloy of copper and graphite, there is an advantage that the slidability is high.

[0046]

As described in detail above, according to the recirculated exhaust gas cooling apparatus of the present invention, since the cooling efficiency of the exhaust gas can be improved, the intake air into the cylinder of the engine can be improved. There is an advantage that a decrease in the amount of air can be prevented and engine performance can be improved.

According to the recirculated exhaust gas cooling apparatus of the present invention, it is not necessary to separately provide the recirculated exhaust gas cooling apparatus and a particulate trap for collecting particulates and the like. There is also an advantage that the cost can be reduced as well as the cost can be reduced. Further, since the cooling efficiency of the exhaust gas can be further improved, there is an advantage that a reduction in the amount of intake air into the cylinder of the engine can be prevented and the engine performance can be improved. Further, since particulates of exhaust gas can be effectively removed, it is possible to prevent the particulates from entering the cylinder of the engine, and to improve the durability of engine parts (for example, pistons, etc.). There is also an advantage that can be.

According to the third aspect of the present invention, since the cooling efficiency of the exhaust gas can be improved with a simple configuration, the amount of intake air into the cylinder of the engine can be reduced. This has the advantage that engine performance can be improved. According to the recirculating exhaust gas cooling device of the present invention, since the seal member is formed by coating the solid lubricant, the slidability can be improved while maintaining the airtightness, There is an advantage that the reliability and durability of the device can be improved.

According to the fifth aspect of the present invention, since the seal member is formed by spraying a solid lubricant, the slidability is improved while maintaining the airtightness. This has the advantage that the reliability and durability of the device can be improved. Further, since the seal member is not configured as a separate member, there is an advantage that the number of parts can be reduced and cost can be reduced.

According to the recirculation exhaust gas cooling apparatus of the present invention, the sliding property can be improved while maintaining the airtightness at low cost, and the reliability and durability of the apparatus can be improved. There is an advantage that it can be increased.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a recirculation exhaust gas cooling device as one embodiment of the present invention.

FIG. 2 is a schematic diagram showing a rotary heat exchanger as a main part in a recirculated exhaust gas cooling device as one embodiment of the present invention.

FIG. 3 is a schematic diagram for explaining an operation of the recirculated exhaust gas cooling device as one embodiment of the present invention.

FIG. 4 is a schematic exploded perspective view showing a recirculation exhaust gas cooling device as a modification of one embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view showing a part of a rotary heat exchanger in a recirculated exhaust gas cooling device as a modified example of one embodiment of the present invention.

FIG. 6 is a diagram schematically showing an exhaust gas recirculation device provided with a conventional recirculation exhaust gas cooling device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Engine 2 Exhaust passage 3 Intake passage 4 Exhaust recirculation passage 4A Upstream part of exhaust recirculation passage 4B Downstream part of exhaust recirculation passage 5 EGR cooler (recirculation exhaust gas cooling device) 5A EGR cooler main body 5a Inlet 5b Outlet 6 EGR valve 7 Exhaust gas recirculation device (EGR device) 10 Rotary heat exchanger as EGR cooler (Rotary heat storage heat exchanger) 10A Housing 10B Core 10D Flange formed on side of housing 10a Exhaust gas inlet 10b Exhaust gas Outlet 10c Inlet for cooling air 10d Outlet for cooling air 11 Cooling gas passage 11A Upstream portion of cooling air passage 11B Downstream portion of cooling gas passage 12, 13 Seal member 20A Outer peripheral surface of cylindrical member 20B Gear portion 21 Partition wall (wall of hole) 22, 22A, 22B Hole 23 Drive mode 24 Drive gear 30 Sealing material 31 Particulate 40 Cooling passage 40a forming a part of exhaust gas recirculation passage 4 Wall of cooling passage 50, 51 Sealing member 50a, 51a Flange of housing (for rotary heat exchanger) Stationary part) 52 V band coupling 52 a Band 52 b V retainer 53 Gasket (O-ring)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shizuo Inaba 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Yoshiyuki Akao 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation

Claims (6)

[Claims] A rotary heat exchanger for exchanging heat by rotating a core is provided in an exhaust gas recirculation passage connecting an exhaust passage and an intake passage of an engine. A recirculation exhaust gas cooling device, characterized in that exhaust gas passing through the exhaust gas recirculation passage is cooled by introducing cooling air into the core. 2. The core is formed of ceramic, and one end of the core is closed and the other end is open, and a hole is opened at one end and the other end is closed. The recirculated exhaust gas cooling device according to claim 1, wherein the holes are configured to be adjacent to each other. 3. The recirculation exhaust gas cooling device according to claim 1, wherein the cooling air is introduced by a radiator fan of the engine or a dedicated fan. 4. A seal member is interposed at a sliding portion where the stationary portion of the rotary heat exchanger slides with the core so as to maintain airtightness, and the seal member is a solid thin metal plate. The recirculation exhaust gas cooling device according to any one of claims 1 to 3, wherein the device is configured by coating with a lubricant. 5. A seal member is interposed between a stationary portion of the rotary heat exchanger and a sliding contact portion of the core in sliding contact with the core to maintain airtightness, and the seal member is a flange portion of the stationary portion. The recirculation exhaust gas cooling device according to any one of claims 1 to 3, wherein the device is configured by directly spraying a solid lubricant on the exhaust gas. 6. The recirculation exhaust gas cooling device according to claim 5, wherein said seal member is mainly made of an alloy of copper and graphite or the like.