JP5096190B2 - Exhaust gas recirculation system - Google Patents

Description

The present invention relates to an exhaust gas recirculation system.

Conventionally, as this type of exhaust gas recirculation system, as disclosed in Patent Document 1, for example, a system in which a part of the exhaust gas is recirculated to the intake system as EGR gas has been proposed.
In this exhaust gas recirculation system, by providing a tank having a drain valve in the middle of the EGR gas passage connecting the exhaust system and the intake system, the condensed water generated by cooling the EGR gas is stored and drained. It is assumed that the condensed water stored by opening the valve can be discharged to the outside.
JP 2007-15495 A

  In the conventional exhaust gas recirculation system, there is a problem that the condensed water can be discharged only when EGR gas is not introduced into the intake system, and the drain valve is controlled according to the state of the engine. There is a problem that it is necessary and the control becomes complicated.

The exhaust gas recirculation system of the present invention has one of the objects to more easily secure the discharge of the condensed water generated by cooling the recirculated exhaust gas, and to achieve at least a part of this object. The following measures were taken.
The present invention is an exhaust gas recirculation system for recirculating a part of exhaust gas to the intake side,
An exhaust passage through which exhaust gas flows formed by an exhaust port of the cylinder head, and an exhaust manifold attached to a mounting surface formed on a surface of the cylinder head through which the exhaust port is opened, through a gasket;
A passage formed in the cylinder head, having a passage opening formed at a position lower than the position where the exhaust port is formed on the mounting surface when the locomotive is mounted, and formed on the mounting surface. A head internal passage communicating with the exhaust port from the recessed groove formed through the passage opening, the exhaust passage having the exhaust side opening opening to the exhaust passage, and the intake side opening opening to the intake side. A return passage communicating with the intake side;
A storage part that is formed as a part of the passage in the head and that is provided in the reflux passage and stores condensed water generated by cooling the exhaust gas;
The gasket is formed by being sandwiched between the cylinder head and the exhaust manifold, and has a first opening having one end opened in the storage portion and a second opening having the other end opened in the exhaust passage. is formed as a water drain passage becomes, the flow velocity of the exhaust gas in the second opening is larger than the flow rate of the exhaust gas in the exhaust-side opening by projecting the said second opening in said exhaust passage having And condensed water discharge means capable of sucking out and discharging the condensed water stored in the storage unit,
It is a summary to provide.

In the exhaust gas recirculation system of the present invention, the condensed water stored in the storage section can be sucked up using the flow of the exhaust gas flowing through the exhaust passage, and the condensed water can be discharged from the storage section.
As described above, since the condensed water can be discharged only by using the flow of the exhaust gas, the discharging property of the condensed water can be ensured more easily. Moreover, the condensed water can always be discharged during operation of the internal combustion engine.

In the exhaust gas recirculation system of the present invention, the first opening can be opened near the bottom surface of the reservoir.
If it carries out like this, it will become easy to submerge in the condensed water which a 1st opening stores in a storage part, As a result, the suction of the condensed water of a storage part can be performed efficiently.

In the exhaust gas recirculation system of the present invention, the first opening may be opened in a manner facing the bottom surface of the storage portion.
If it carries out like this, it will become easy to be submerged in the condensed water which a 1st opening stores in a storage part, As a result, the suction of the condensed water of a storage part can be performed more efficiently.

In the exhaust gas recirculation system of the present invention, the second opening may be opened in a direction orthogonal to the flow of the exhaust gas flowing through the exhaust passage.
If it carries out like this, the pressure of 2nd opening periphery can be reduced more efficiently, As a result, the condensed water stored in a storage part can be sucked up more efficiently.

Further, Oite the exhaust gas recirculation system of the present invention, the water drain passage can be formed in the gasket.
By doing so, it is only necessary to form a water drainage passage in the gasket, so that the condensate drainage can be more easily ensured.

Further, Oite the exhaust gas recirculation system of the present invention, the gasket has a first port opening to said formed corresponding to the exhaust port, a first protrusion protruding portion of the first port opening A first closing portion that closes the concave groove and the passage opening when attached to the attachment surface, and an end portion facing the first port opening of the first projecting portion from the first closing portion. A first recess formed over a first opening blocking portion that closes the passage opening, and a through hole formed through the portion corresponding to the first opening blocking portion of the first recess. 1 gasket, a second port opening formed corresponding to the first port opening, a second protrusion formed corresponding to the first protrusion, and a first closing part A second blocking portion formed at a position and formed corresponding to the first recess A second gasket having two recesses, and the drainage passage is a state in which the first gasket and the second gasket are combined so that the through hole opens to the storage portion side. It can also be formed by being sandwiched between the cylinder head and the exhaust manifold.
In this case, the drainage passage can be more easily secured because the first gasket and the second gasket are simply disposed between the cylinder head and the exhaust manifold.

Further, Oite the exhaust gas recirculation system of the present invention, the water drain passage can be formed between the gasket and the exhaust manifold.
In this way, the drainage passage is only formed between the gasket and the exhaust manifold, so that the condensate drainage can be more easily ensured.

  Next, the best mode for carrying out the present invention will be described using examples.

  1 to 5 show a first embodiment, FIG. 1 is a schematic configuration diagram of an internal combustion engine, and FIG. 2 is an exploded view of a cylinder head and a gasket as viewed from the direction A of FIG. FIG. 3 is an exploded perspective view of the gasket. 4 is a view in the direction of arrow A in a state where the gasket of FIG. 3 is attached to the cylinder head. FIG. 5 is an enlarged longitudinal sectional view of a main part in a state where an exhaust manifold is attached with a gasket interposed in the cylinder head.

As shown in FIG. 1, the internal combustion engine 1 is provided with a cylinder head 3 on a cylinder block 2 and an oil pan 4 below the cylinder block 2. In the figure, reference numeral 5 denotes a flywheel.
An exhaust manifold 6 that forms an exhaust passage is attached to the attachment surface 3 a of the cylinder head 3, and a catalyst 7 is provided at the downstream end of the exhaust manifold 6.
An intake manifold 8 that forms an intake passage is attached to the surface of the cylinder head 3 opposite to the attachment surface 3 a, and the plurality of intake manifolds 8 are connected to the intake manifold collector 9.
A water outlet 10 is attached to a side surface 3b orthogonal to the mounting surface 3a of the cylinder head 3, and an EGR passage 10c is formed in the water outlet 10, and the water outlet 10 communicates with the EGR passage 10c. Is provided with an EGR valve 11.
An opening 10b communicating with the EGR passage 10c is formed in the flange surface 10a of the water outlet 10, and an EGR pipe 12 is attached to the flange surface 10a so as to communicate with the opening 10b. Is connected to the intake manifold collector 9.

As shown in an enlarged view in FIG. 2, a plurality of exhaust ports 13 are opened in an attachment surface 3 a for attaching the exhaust manifold 6 of the cylinder head 3, and the internal combustion engine 1 is connected to the exhaust port 13 to communicate with the vehicle. A concave groove 14 is formed in the mounting surface 3a so as to be inclined obliquely downward when mounted on the mounting surface 3a. One end of the concave groove 14 is attached to the mounting surface 3a as shown in FIG. The in-head passage 15 is formed with the other end opened to the side surface 3b. The in-head passage 15 is connected to a passage 15 ′ extending in parallel with the exhaust passage R in the exhaust port 13 from a passage opening 15a that opens to the mounting surface 3a toward the inside of the head, and is connected to the passage 15 ′ in the head at right angles. The passage 15 '' extends to the passage opening 15b that opens to the side surface 3b, and communicates with the EGR passage 10c through the passage opening 15b. Thus, the recirculation passage 16 is formed by the concave groove 14, the head inner passage 15, the EGR passage 10 c and the EGR pipe 12, and the internal combustion engine 1 is mounted on the vehicle among the recirculation passage 16. It is arranged at the lowest position in the state.
As shown in FIG. 5, the flange portion 6 a of the exhaust manifold 6 is attached to the exhaust port 13 of the cylinder head 3 with the gaskets 18 and 19 sandwiched therebetween, and the exhaust passage R and the exhaust manifold in the exhaust port 13 are attached. The exhaust passage R in 6 is communicated.

The gasket is composed of two gaskets 18 and 19, and as shown in an exploded view in FIG. 3, the first gasket 18 and the second gasket 19 are overlapped and used in alignment.
A first port opening 18a corresponding to the exhaust port 13 of the cylinder head 3 is formed through the first gasket 18, and a first port opening is formed at a lower left part of the first port opening 18a. A first projecting portion 18b is formed in the projecting portion 18a. The first projecting portion 18b includes a first closing portion 18c that closes the recessed groove 14 and the passage opening 15a in the attached state. The first projecting portion 18b has a first port opening. A first recess 18d is formed by being recessed toward the cylinder head 3 from the end 18a 'facing 18a to a position corresponding to the passage opening 15a in the first closing portion 18c. That is, the first concave portion 18d is formed at a position corresponding to the concave groove 14 formed in the mounting surface 3a when the first gasket 18 contacts the cylinder head 3. A through hole 18e is formed in a penetrating manner in a portion corresponding to the passage opening 15a of the first recess 18d.

On the other hand, a second port opening 19a is formed through the second gasket 19 in correspondence with the first port opening 18a of the first gasket 18, and projects into the second port opening 19a. A second projecting portion 19b corresponding to the first projecting portion 18b is formed, and a second closing portion 19c is provided at a position corresponding to the first closing portion 18c, and an exhaust manifold corresponding to the first recessed portion 18d. A second recess 19d is formed by being recessed toward the 6th side.
When the first gasket 18 and the second gasket 19 are overlapped, a drain passage 20 is formed by the first recess 18d of the first gasket 18 and the second recess 19d of the second gasket 19, as shown in FIG. A through hole 18e of the first gasket 18 is located at the lower end of the drainage passage 20, and this through hole 18e becomes a first opening 20a of the drainage passage 20 that opens near the bottom surface of the head internal passage 15 in the attached state. The first projecting portion 18b and the second projecting portion 19b project into the exhaust passage R in the attached state, and the second opening 20b at the upper end of the drainage passage 20 extends in a direction perpendicular to the flow of the exhaust gas flowing through the exhaust passage R. Opened.

The drainage passage 20 having a first opening 20a at the lower end and a second opening 20b at the upper end formed between the first gasket 18 and the second gasket 19 allows condensed water accumulated in the head inner passage 15 to be exhausted. Condensed water discharging means capable of discharging in R is formed. The reason for the generation of condensed water and the reason for the accumulation in the head passage 15 will be described later.
A recirculation passage 16 is formed by the concave groove 14 formed in the cylinder head 3, the head inner passage 15, the EGR passage 10 c in the water outlet 10, and the EGR pipe 12, and the exhaust passage 16 is exhausted through the recirculation passage 16. A part of the exhaust gas flowing through the passage R can be recirculated as EGR gas from the intake manifold collector 9 to the intake passage in the intake manifold 8.

In the internal combustion engine 1 having the exhaust circulation system having such a structure, when the EGR gas is cooled when the engine is stopped or the like, water in the EGR gas is condensed and condensed water is generated in the reflux passage 16. The generated condensed water accumulates in the head inner passage 15 arranged at the lowest position in the state where the internal combustion engine 1 is mounted on the vehicle in the reflux passage 16.
During operation of the internal combustion engine 1, exhaust gas flows through the exhaust passage R from the exhaust port 13 toward the exhaust manifold 6, and the protruding portions 18 b and 19 b of the gaskets 18 and 19 protrude into the exhaust passage R. In this portion, the flow rate of the exhaust gas becomes large, thereby reducing the pressure around the second opening 20b, and the lower end of the second opening 20b and the lower end submerged in the condensed water stored in the in-head passage 15. A pressure difference is generated between the first opening 20a and the condensed water in the in-head passage 15 is sucked into the drainage passage 20, and the condensed water flows into the exhaust passage R from the second opening 20b at the upper end by the principle of spraying. Will be discharged.

That is, the flow of the exhaust gas flowing in the exhaust passage R can be used to suck up and discharge the condensed water in the head passage 15, and the discharge of the condensed water can be easily ensured, so that the operation of the internal combustion engine 1 can be performed. The inside can always discharge condensed water.
Since the first opening 20a is opened near the bottom surface of the head internal passage 15, the condensed water in the head internal passage 15 can be efficiently sucked up. Further, since the second opening 20b is opened in a direction orthogonal to the flow of the exhaust gas, that is, upward, the pressure around the second opening 20b can be efficiently reduced by the flow of the exhaust gas, and the condensation is efficiently performed. Can suck up water.

  Further, in this example, the drainage passage 20 can be formed simply by overlapping the first gasket 18 and the second gasket 19 and interposing them in a sandwiched manner between the cylinder head 3 and the exhaust manifold 6. Emission can be easily secured.

  In the first embodiment, the first recess 18d is formed in the first gasket 18, the second recess 19d is formed in the second gasket 19, and the first recess 18d and the second recess 19d are combined to form a water drain passage. However, the water drainage passage 20 may be formed by forming a recess in only one of the first gasket 18 and the second gasket 19.

Next, FIGS. 6, 7 and 8 show a second embodiment.
In the second embodiment, the drainage passage 20 is formed between the cylinder head 3 and the exhaust manifold 6 using a single gasket. That is, only the first gasket 18 is used, and as shown in FIG. 6, the first gasket 18 includes a first port opening 18 a formed corresponding to the exhaust port 13 of the cylinder head 3, and a first port opening. A first projecting portion 18b projecting to a part of 18a, a first closing portion 18c for closing the recessed groove 14 and the passage opening 15a formed in the mounting surface 3a on the cylinder head 3 side, and a first projecting portion 18b A first concave portion 18d formed in a concave shape on the cylinder head 3 side is provided from the end portion 18a 'facing the one-port opening 18a to a position corresponding to the passage opening 15a in the first closing portion 18c. . That is, the first concave portion 18d is formed at a position corresponding to the concave groove 14 formed in the mounting surface 3a when the first gasket 18 contacts the cylinder head 3. A through hole 18e is formed in a penetrating manner in a portion corresponding to the passage opening 15a of the first recess 18d.

A protruding portion 6 b that protrudes into the exhaust passage R is formed on the inner periphery of the flange portion 6 a of the exhaust manifold 6 attached to the cylinder head 3. That is, the protruding portion 6b is formed with the same protruding dimension at a position corresponding to the first protruding portion 18b of the gasket 18.
In the state of FIG. 8 in which the flange portion 6a of the exhaust manifold 6 is attached to the mounting surface 3a of the cylinder head 3 with the first gasket 18 interposed therebetween, and the first gasket 18 is sandwiched between the cylinder head 3 and the exhaust manifold 6. The first port opening 18a of the gasket 18 is aligned with the exhaust port 13 and the exhaust passage R in the exhaust manifold 6 to form a passage through which exhaust gas flows, and the first protrusion 18b of the first gasket 18 and the exhaust manifold 6 The protrusion 6b is aligned to form a drainage passage 20 therein, and the second opening 20b at the upper end of the drainage passage 20 is upward in the exhaust passage R perpendicular to the flow direction of the exhaust gas flowing through the exhaust passage R. Is opened. Further, the first opening 20 a at the lower end of the drainage passage 20 by the through hole 18 e is opened near the bottom surface of the in-head passage 15 of the cylinder head 3.

As described above, the vertical drainage passage 20 having the first opening 20 a and the second opening 20 b between the first gasket 18 and the flange portion 6 a of the exhaust manifold 6 using the single first gasket 18. Can be easily formed.
Also in this example, the condensed water generated by cooling the EGR gas is accumulated in the head internal passage 15 arranged at the lowest position in the state where the internal combustion engine 1 is mounted on the vehicle in the recirculation passage 16, and During operation of the engine 1, exhaust gas flows through the exhaust passage R from the exhaust port 13 toward the exhaust manifold 6, and the first protrusion 18 b of the first gasket 18 and the protrusion of the exhaust manifold 6 are in the exhaust passage R. Since 6b protrudes, the flow rate of the exhaust gas becomes large at this portion, thereby reducing the pressure around the second opening 20b, and the second opening 20b and the inside of the condensed water accumulated in the head passage 15 A pressure difference is generated between the lower end of the first opening 20a submerged in the water, the condensed water in the head inner passage 15 is sucked into the water draining passage 20, and the condensed water is discharged into the second upper end by the principle of spraying. And it is discharged from the mouth 20b into the exhaust passage R.

Next, FIGS. 9, 10 and 11 show a third embodiment.
In the third embodiment, the gasket 21 sandwiched between the cylinder head 3 and the exhaust manifold 6 is formed in a structure as shown in FIG.
The gasket 21 has a port opening 21 a corresponding to the exhaust port 13 of the cylinder head 3, and a protruding portion 21 b protruding from a part of the port opening 21 a is formed. A closing portion 21c capable of closing the recessed groove 14 and the passage opening 15a formed in the mounting surface 3a is provided, and a through hole 21e is formed in a penetrating manner in a portion corresponding to the passage opening 15a of the closing portion 21c. It is formed.
Further, a protruding portion 6b is formed on the inner periphery of the flange portion 6a of the exhaust manifold 6 so as to protrude into the exhaust passage R. The protruding portion 6b is equivalent to a position corresponding to the protruding portion 21b of the gasket 21. A recessed portion 6c is formed on the cylinder head 3 side of the protruding portion 6b and extends in the downward direction along the flange portion 6a.

  In a state where the gasket 21 is sandwiched and attached between the cylinder head 3 and the flange portion 6a of the exhaust manifold 6, a drainage passage 20 extending vertically between the gasket 21 and the recess 6c formed in the flange portion 6a of the exhaust manifold. Thus, the upper end of the drainage passage 20 protrudes into the exhaust passage R between the protruding portion 21b of the gasket 21 and the protruding portion 6b of the exhaust manifold 6, and is orthogonal to the exhaust gas flowing in the exhaust passage R. The first opening 20a is formed in the vicinity of the bottom surface of the in-head passage 15 by the through hole 21e of the gasket 21.

  Also in this example, the drainage passage 20 can be secured with a simple structure, and the condensed water generated by cooling the EGR gas is most in the state where the internal combustion engine 1 is mounted on the vehicle in the return passage 16. During the operation of the internal combustion engine 1, the exhaust gas flows in the exhaust passage R from the exhaust port 13 toward the exhaust manifold 6, and the gasket 21 is placed in the exhaust passage R. Since the protruding portion 21b of the exhaust manifold 6 and the protruding portion 6b of the exhaust manifold 6 protrude, the flow velocity of the exhaust gas increases at this portion, and the pressure around the second opening 20b decreases, and the second opening 20b and the inside of the head A pressure difference is generated between the first opening 20 a at the lower end submerged in the condensed water stored in the passage 15, and the condensed water in the head inner passage 15 is sucked into the drainage passage 20. It is, so that the condensed water on the principle of spray is discharged from the second opening 20b of the upper end into the exhaust passage R.

  In each of the above embodiments, a gasket is used to form the drain passage 20 for discharging condensed water. However, a straw-like member is removed from the exhaust passage R without using a gasket. The lower end of the straw-shaped member is provided so as to be inserted toward the in-head passage 15 so that the lower end of the straw-like member is opposed to the bottom surface of the in-head passage 15. It is also possible to adopt a structure that can be sucked and discharged in the exhaust passage R on the principle of spraying. In this case, since the lower end of the straw-like member, that is, the opening on the side of the head internal passage 15 is provided opposite to the bottom surface of the head internal passage 15, it becomes easy to be submerged in the condensed water accumulated in the head internal passage 15. Condensed water can be efficiently sucked up.

  In each embodiment, the first gasket 18 and the second gasket 19 are formed with the first projecting portion 18b and the second projecting portion 19b projecting into the first port opening 18a and the second port opening 19a. Any structure may be used as long as the flow rate of the exhaust gas in the second opening 20b can be made larger than the flow rate of the exhaust gas in the portion where the concave groove 14 opens. For example, as shown in the modified examples of FIGS. The first protrusion 18b '' and the second protrusion 19b projecting the opposing portions of the first gasket 18 and the second gasket 19 facing the second opening 20b into the first port opening 18a and the second port opening 19a. Or the diameters of the first port opening 18a and the second port opening 19a are different from the diameter of the exhaust port 13, as shown in the modified examples of FIGS. No problem even as forming a throttle portion O which was also small.

  As mentioned above, although embodiment of this invention was described using the Example, this invention is not limited to such an Example, In the range which does not deviate from the summary of this invention, it can implement with a various form. Of course.

It is a schematic block diagram of an internal combustion engine. It is a disassembled perspective view of the gasket attached to the cylinder head of 1st Example, and the attachment surface of a cylinder head. It is a disassembled perspective view of the gasket comprised by two sheets. It is an A direction arrow directional view in FIG. 1 of the state which attached the gasket of 2 sheets to the cylinder head. It is a longitudinal cross-sectional enlarged block diagram of the attachment part of the exhaust manifold attached to the cylinder head through the gasket. It is a block diagram of the gasket of 2nd Example. It is an A direction arrow directional view in the state where the gasket of the 2nd example was attached to the cylinder head. It is a principal part longitudinal cross-sectional enlarged block diagram of the state which attached the exhaust manifold to the cylinder head through the gasket of 2nd Example. It is a block diagram of the gasket of 3rd Example. FIG. 10 is a view in the direction of arrow A in a state where the gasket of FIG. 9 is attached to the cylinder head. It is a principal part longitudinal cross-sectional enlarged block diagram of the state which attached the exhaust manifold to the cylinder head through the gasket of 3rd Example. It is an A direction arrow view of the state which showed the modification and attached the gasket to the cylinder head. FIG. 13 is an enlarged configuration diagram of a main part in a state where an exhaust manifold is attached to a cylinder head with a gasket of a modification of FIG. It is an A direction arrow view of the state which showed the further modification and attached the gasket to the cylinder head. It is a principal part longitudinal cross-section enlarged view of the state which attached the exhaust manifold to the cylinder head through the gasket of the modification of FIG.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Cylinder block 3 Cylinder head 3a Mounting surface 3b Side surface 6 Exhaust manifold 6a Flange part 6b Projection part 7 Catalyst 8 Intake manifold 9 Inner manifold collector 10 Water outlet 10b Opening 10c EGR passage 11 EGR valve 12 EGR pipe (Intake side opening)
13 Exhaust port 14 Concave groove (exhaust side opening)
15 Head passage (reservoir)
15a passage opening 15b passage opening 15 'passage 15''passage 16 reflux passage 18 first gasket 18a first port opening 18b, 18b''first protrusion 18c first closing portion 18d first recess 18e first recess 19e through hole 19 second Gasket 19a 2nd port opening 19b, 19b '' 2nd protrusion part 19c 2nd blocking part 19d 2nd recessed part 20 Drain passage (condensed water discharge means)
20a 1st opening 20b 2nd opening 21 Gasket 21a Port opening 21b Protrusion part 21c Blocking part 21e Through-hole R Exhaust passage O Restriction part

Claims (7)

An exhaust gas recirculation system that recirculates part of exhaust gas to the intake side,
An exhaust passage through which exhaust gas flows formed by an exhaust port of the cylinder head, and an exhaust manifold attached to a mounting surface formed on a surface of the cylinder head through which the exhaust port is opened, through a gasket;
A passage formed in the cylinder head, having a passage opening formed at a position lower than the position where the exhaust port is formed on the mounting surface when the locomotive is mounted, and formed on the mounting surface. A head internal passage communicating with the exhaust port from the recessed groove formed through the passage opening, the exhaust passage having the exhaust side opening opening to the exhaust passage, and the intake side opening opening to the intake side. A return passage communicating with the intake side;
A storage part that is formed as a part of the passage in the head and that is provided in the reflux passage and stores condensed water generated by cooling the exhaust gas;
The gasket is formed by being sandwiched between the cylinder head and the exhaust manifold, and has a first opening having one end opened in the storage portion and a second opening having the other end opened in the exhaust passage. is formed as a water drain passage becomes, the flow velocity of the exhaust gas in the second opening is larger than the flow rate of the exhaust gas in the exhaust-side opening by projecting the said second opening in said exhaust passage having And condensed water discharge means capable of sucking out and discharging the condensed water stored in the storage unit,
An exhaust gas recirculation system comprising: The exhaust gas recirculation system according to claim 1 , wherein the first opening is opened near a bottom surface of the storage portion. The exhaust gas recirculation system according to claim 1 or 2 , wherein the first opening is opened in a manner facing the bottom surface of the storage portion. The second opening is an exhaust gas recirculation system according to the is opened in a direction perpendicular to the flow of the exhaust gas flowing through the exhaust passage formed by claims 1 to any one of claims 3. The exhaust gas recirculation system according to any one of claims 1 to 4 , wherein the drainage passage is formed in the gasket . The gasket is
A first port opening formed corresponding to the exhaust port; a first projecting portion projecting into a part of the first port opening; and the recessed groove and the passage when attached to the mounting surface. A first closing portion that closes the opening, and an end portion of the first projecting portion that faces the first port opening, and a first opening closing portion that blocks the passage opening of the first closing portion. A first gasket having a first recess and a through-hole formed in a portion corresponding to the first opening closing portion of the first recess;
A second port opening formed corresponding to the first port opening, a second protrusion formed corresponding to the first protrusion, and a position corresponding to the first blocking part. A second gasket having a second closing portion and a second recess formed corresponding to the first recess,
Formed from
The drainage passage is formed by being sandwiched between the cylinder head and the exhaust manifold in a state where the first gasket and the second gasket are combined so that the through-hole opens to the storage portion side. The exhaust gas recirculation system according to any one of claims 1 to 5 . The exhaust gas recirculation system according to any one of claims 1 to 6 , wherein the drainage passage is formed between the gasket and the exhaust manifold .

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