JP5614080B2 - Exhaust gas recirculation device for internal combustion engine - Google Patents

Description

  The present invention relates to an exhaust gas recirculation device for an internal combustion engine.

  In order to reduce NOx emissions and pump loss of an internal combustion engine, a technique for returning a part of the exhaust gas as EGR gas to the intake air is effective. However, if the EGR gas amount is increased, the fuel does not burn well and PM There is a trade-off that the amount of emissions increases, and there is a problem that the EGR rate cannot be increased to some extent. On the other hand, a technique has been proposed in which EGR gas and air are stratified in the combustion chamber to increase the EGR rate without deteriorating combustion.

  For example, in Patent Document 1, two intake ports are provided per cylinder, EGR gas is supplied to only one of the two intake ports, and the intake port to which EGR gas is supplied flows into the combustion chamber. By arranging and configuring the gas to swirl along the outer periphery of the combustion chamber, and by arranging and configuring the intake port to which EGR gas is not supplied so that the gas flowing into the combustion chamber swirls through the center of the combustion chamber A technique is described in which an air layer is formed in the center of the combustion chamber, an EGR gas layer is formed so as to surround the outer periphery of the air layer, and the EGR gas and air are stratified in the combustion chamber.

JP 2008-101544 A

  In the technique described in Patent Document 1, air is supplied to both the intake port to which EGR gas is supplied and the intake port to which EGR gas is not supplied, so that it can be supplied into the cylinder in an operation state in which the air amount increases. There is a problem that the amount of EGR gas decreases and it is difficult to increase the EGR rate.

  The present invention has been made in view of this point, and enables an EGR rate to be further increased while suppressing deterioration of combustion in an exhaust gas recirculation device for an internal combustion engine that stratifies EGR gas and air in a combustion chamber. The purpose is to provide technology.

The present invention for solving the above problems is as follows.
An exhaust gas recirculation device for an internal combustion engine comprising an EGR device that recirculates a part of exhaust gas of the internal combustion engine as EGR gas to a combustion chamber,
An intake port communicating with the combustion chamber of the internal combustion engine has a space between an inner passage having an inner diameter smaller than the inner diameter of the intake port, an outer wall surface of the inner passage, and an inner wall surface of the intake port. A double tube structure formed with an outer passage;
An intake passage of the internal combustion engine communicates with the inner passage;
The EGR device recirculates EGR gas to the outer passage.

When gas flows into the combustion chamber from the intake port having such a double pipe structure, the gas flowing into the combustion chamber from the inner passage of the intake port is localized in the region near the central axis at the upper part of the combustion chamber, and The gas flowing into the combustion chamber from the outer passage is localized near the inner wall surface of the combustion chamber (the inner wall surface of the cylinder) and near the bottom surface of the combustion chamber (the top surface of the piston). Therefore, a layered gas distribution is formed in the combustion chamber so that the gas flowing in from the outer passage wraps the gas flowing in from the inner passage.

  According to the configuration of the present invention, the gas flowing into the combustion chamber from the inner passage of the intake port is air (fresh air) supplied from the intake passage, and the gas flowing into the combustion chamber from the outer passage of the intake port is EGR. EGR gas supplied by the device.

  Therefore, according to the present invention, air or a mixture of air and fuel is localized in the region near the central axis at the upper part of the combustion chamber, and is surrounded by the combustion chamber wall surface and the piston top surface so as to wrap it from the outside and the lower side. A layered gas distribution in which EGR gas is localized is formed in the combustion chamber.

  In the case of a spark ignition type internal combustion engine, the spark plug is provided near the top central axis of the combustion chamber, so a layer of air or a combustible mixture is formed around the spark plug, and an EGR gas layer is formed so as to enclose it. Will be.

  Therefore, deterioration of combustion can be suppressed even if a large amount of EGR gas is introduced. The EGR gas layer is formed not only near the wall surface of the combustion chamber but also near the top surface of the piston below the combustion chamber, which hardly affects the combustibility, so that more EGR is suppressed while suppressing deterioration of combustion. The gas can be refluxed.

  Further, in the present invention, since the intake passage does not communicate with the outer passage, air does not enter the gas flowing from the outer passage into the combustion chamber. Accordingly, it is possible to suppress a decrease in the amount of EGR gas in an operation state in which the amount of air increases, and a high EGR rate can be achieved in a wider range of operation conditions.

  In the present invention, the inner passage and the outer passage may have a coaxial structure. According to this configuration, air or a combustible gas mixture flowing from the inner passage into the combustion chamber and EGR gas flowing from the outer passage into the combustion chamber can form the stratified gas distribution as described above in the combustion chamber. .

  In the above configuration, the inner passage, the outer passage, and the combustion chamber may have a coaxial structure. In this case, since the intake port allows gas to flow into the combustion chamber from the vicinity of the upper center of the combustion chamber, air or a combustible mixture flowing from the inner passage into the combustion chamber flows into the combustion chamber from the outer passage near the upper central axis of the combustion chamber. The EGR gas to be localized can be localized near the wall surface of the combustion chamber and the top surface of the piston, and the formation of the stratified gas distribution is suitably performed.

  The present invention can also be applied to an internal combustion engine having two intake ports per cylinder. In such an internal combustion engine, when the double pipe structures of the two intake ports are both coaxial, the cross section perpendicular to the central axis of the combustion chamber is outside the two intake ports between the inner passages of the two intake ports. A part of the passage is sandwiched.

  Therefore, the gas distribution formed in the combustion chamber flows in from the portion between the two inner passages of the air or combustible mixture and the outer passage flowing in from the inner passage of the two intake ports near the upper central axis of the combustion chamber. EGR gas flowing from a portion other than the portion sandwiched between the two inner passages of the outer passage near the combustion chamber wall and near the combustion chamber bottom surface (piston top surface) is localized. It becomes the existing layered gas distribution.

In such a gas distribution in the combustion chamber, a part of the EGR gas is included in the air or combustible air-fuel mixture localized around the spark plug, but most of the EGR gas is localized near the combustion chamber wall and bottom surface. Therefore, the influence on combustibility is small, and a high EGR rate can be realized while suppressing deterioration of combustion.

  On the other hand, the double pipe structure of the two intake ports may be configured such that the central axis of the inner passage of each intake port is eccentric to the other intake port with respect to the central axis of the outer passage. Alternatively, the double pipe structure of the two intake ports may be configured such that the central axis of the inner passage of each intake port is eccentric to the central axis of the combustion chamber with respect to the central axis of the outer passage.

  In any configuration, the outer passage portion sandwiched between the inner passages of the two intake ports is smaller than in the case where the double pipe structures of the two intake ports are both coaxial. Therefore, in the gas distribution formed in the combustion chamber, the amount of EGR gas in the air or a mixture of combustible air-fuel mixture and EGR gas localized near the upper central axis of the combustion chamber is reduced.

  Therefore, the influence on the combustibility when the EGR rate is increased can be further reduced, and a higher EGR rate can be realized while suppressing the deterioration of combustion.

  In the present invention, a fuel injection valve for injecting fuel into the inner passage of the intake port can be provided. According to this configuration, since no fuel is mixed into the EGR gas, it is possible to suitably suppress the deterioration of combustion and the discharge of unburned content.

  In the present invention, the double pipe structure may be formed only in a partial section of the intake port near the connection portion with the combustion chamber. In the double-pipe structure of the intake port of the present invention, there is a possibility that the air flowing through the inner passage rises in temperature due to heat received from the high-temperature EGR gas flowing through the outer passage, but the double-pipe structure is connected to the combustion chamber. If limited to a part of the vicinity, the temperature rise of the air can be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, in the exhaust gas recirculation apparatus of the internal combustion engine which stratifies EGR gas and air in a combustion chamber, the technique which makes it possible to raise an EGR rate further, suppressing combustion deterioration can be provided.

FIG. 3 is a diagram illustrating a schematic structure inside a cylinder and an intake port of the internal combustion engine according to the first embodiment. FIG. 2 is a view of a cylinder and an intake port of the internal combustion engine according to the first embodiment when viewed from above. FIG. 3 is a diagram schematically illustrating a gas distribution formed in a combustion chamber of the internal combustion engine according to the first embodiment. FIG. 6 is a view of a cylinder and an intake port of an internal combustion engine according to a second embodiment as viewed from above. FIG. 6 is a diagram illustrating a schematic structure of a cylinder and an intake port of an internal combustion engine according to a second embodiment. FIG. 6 is a view of a cylinder and an intake port of an internal combustion engine according to a third embodiment as viewed from above. FIG. 6 is a diagram schematically illustrating a gas distribution formed in a combustion chamber of an internal combustion engine according to a third embodiment. It is the figure which looked at the cylinder and intake port of the internal combustion engine which concerns on Example 4 from the top. FIG. 10 is a view of a cylinder and an intake port of an internal combustion engine according to a modification of the fourth embodiment as viewed from above.

  Hereinafter, embodiments of the present invention will be described in detail. The dimensions, materials, shapes, relative arrangements, and the like of the components described in the present embodiment are not intended to limit the technical scope of the invention to those unless otherwise specified.

Example 1
FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine according to a first embodiment of the present invention. FIG. 1 shows a cross section of a cylinder 2 and an intake port 5 of an internal combustion engine 1. A piston 4 is inserted into the cylinder 2 so as to be slidable in the vertical direction, and a combustion chamber 3 is defined by the inner wall surface of the cylinder 2 and the top surface of the piston 4.

  An opening 11 is provided at the center of the top of the combustion chamber 3 (near the central axis of the combustion chamber 3), and the intake port 5 is connected to the opening 11. The intake port 5 includes an inner passage 7 having an inner diameter smaller than the inner diameter of the intake port 5 and an outer passage 6 that is a space between the outer wall surface 14 of the inner passage 7 and the inner wall surface 15 of the intake port 5. , Is a double tube structure formed.

  An intake passage 10 for taking in air from the outside communicates with the inner passage 7, and an EGR passage 8 communicates with the outer passage 6. The EGR passage 8 communicates with an exhaust passage (not shown) of the internal combustion engine 1, and a part of the exhaust gas of the internal combustion engine 1 returns to the combustion chamber as EGR gas through the EGR passage 8.

  The EGR passage 8 functions as the EGR device of the present invention. The internal combustion engine 1 is provided with a fuel injection valve 9 that injects fuel into the inner passage 7 of the intake port 5. In order to simplify the drawing, components included in the internal combustion engine 1 such as an intake valve, an exhaust port, an exhaust valve, and a spark plug are not shown. The same applies to other drawings described later.

  FIG. 2 is a top view of the cylinder 2 described above. An opening 11 is provided in the vicinity of the central axis C of the cylinder 2 at the top of the combustion chamber, and the intake port 5 is connected to the opening 11. An inner passage 7 and an outer passage 6 are formed inside the intake port 5. The internal combustion engine 1 includes a fuel injection valve 9 that injects fuel into the inner passage 7.

  As shown in FIGS. 1 and 2, the inner passage 7 and the outer passage 6 have a substantially coaxial structure, and a structure that is substantially coaxial with the central axis C of the combustion chamber 3 in the vicinity of the connection portion with the opening 11 of the combustion chamber 3. It has become. As shown in FIG. 2, air from the inner passage 7 flows into the central portion of the combustion chamber 3, and EGR gas from the outer passage 6 flows into the periphery thereof.

  As a result, as shown in FIG. 1, the mixture of air and fuel flowing into the combustion chamber 3 from the inner passage 7 is localized in a region near the central axis in the upper portion of the combustion chamber 3, and from the outer passage 6 to the combustion chamber. The EGR gas that has flowed into the combustion chamber 3 is localized near the inner wall surface of the combustion chamber 3 (inner wall surface of the cylinder 2) and near the bottom surface of the combustion chamber 3 (top surface of the piston 4).

  That is, a layered gas distribution is formed in the combustion chamber 3 such that the EGR gas GE flowing from the outer passage 6 wraps the air-fuel mixture GA flowing from the inner passage 7.

  FIG. 3 is a view showing an AA cross section of the gas distribution in the combustion chamber 3 of FIG. As shown in FIG. 3, the air-fuel mixture GA is localized in a region in the vicinity of the central axis C of the combustion chamber 3, and the EGR gas GE is localized around it.

  The internal combustion engine 1 is provided with a spark plug (not shown) at the center of the top of the combustion chamber 3 (near the central axis C), and the ignition plug ignites a combustible mixture of air and fuel to burn in the combustion chamber 3. Is done.

The internal combustion engine 1 of the present embodiment includes the intake port 5 having the double pipe structure as described above, and the air flowing in from the inner passage 7, the combustible mixture of fuel, and the EGR gas flowing in from the outer passage 6 are shown in FIG. As shown in FIG. 3, since it is distributed in a layered manner in the combustion chamber 3, a large amount of EGR is increased by increasing the EGR rate.
Even when the gas is recirculated, it is possible to suppress the EGR gas from being mixed at a high concentration in the combustible air-fuel mixture near the spark plug.

  Therefore, since it is possible to perform a large amount of EGR without causing deterioration of combustion, the effect of reducing the NOx emission amount and the effect of reducing the pump loss by increasing the EGR rate are sufficiently exhibited.

  Further, in the internal combustion engine 1 of the present embodiment, the intake passage 10 is not communicated with the outer passage 6 and only the EGR passage 8 is communicated, so that the gas flowing into the combustion chamber 3 from the outer passage 6. Air is not mixed in. Accordingly, it is possible to suppress a decrease in the EGR gas amount even in an operation state in which the air amount increases, and it is possible to operate at a high EGR rate under a wider range of operation conditions.

(Example 2)
In the first embodiment, the configuration in which the opening at the top of the combustion chamber 3 to which the intake port 5 is connected is provided at the center of the top of the combustion chamber 3 (near the central axis C of the combustion chamber 3). The position where the opening to be connected is not limited to this.

  FIG. 4 is a diagram showing a schematic configuration of an internal combustion engine according to the second embodiment of the present invention. FIG. 4 is a view of the cylinder 2 as viewed from above, similarly to FIG. 2 of the first embodiment. As shown in FIG. 4, in this embodiment, the opening 12 is provided outside the central axis C of the combustion chamber 3, and the intake port 50 is connected to the opening 12.

  Inside the intake port 50, as in the intake port 5 of the first embodiment, an inner passage 70 and an outer passage 60 are formed. The internal combustion engine 1 of this embodiment is also provided with a fuel injection valve 9 that injects fuel into the inner passage 70.

  FIG. 5 is a diagram showing a cross section of the cylinder 2 and the intake port 50 of the internal combustion engine 1 of the present embodiment, similarly to FIG. 1 of the first embodiment. As described above, in this embodiment, the opening 12 to which the intake port 50 is connected is provided at a position outside the center of the top of the combustion chamber 3.

  The intake port 50 includes therein an inner passage 70 having an inner diameter smaller than the inner diameter of the intake port 50, and an outer passage 60 that is a space between the outer wall surface 140 of the inner passage 70 and the inner wall surface 150 of the intake port 50. , Is a double tube structure formed.

  Note that, unlike the first embodiment, the intake port 50 of this embodiment has a double-pipe structure only in a partial section on the side close to the connection portion with the opening 12 of the intake port 50. Thereby, the temperature rise of the air which flows through the inner side passage 70 by the heat receiving from the high temperature EGR gas which flows through the outer side passage 60 can be suppressed.

  Even if the opening 12 to which the intake port 50 is connected is not provided at the center of the top of the combustion chamber 3 as in this embodiment, the air / fuel mixture flows into the combustion chamber 3 from the inner passage 70. When the EGR gas flows into the combustion chamber 3 from the outer passage 60, as shown in FIG. 5, a mixture of air and fuel is localized in the vicinity of the upper central axis in the combustion chamber 3. EGR gas is localized in the vicinity of the inner wall surface of the combustion chamber 3 and the bottom surface of the combustion chamber 3 (the top surface of the piston 4) so as to wrap the air-fuel mixture in the center.

  Therefore, also in this embodiment, the AA cross section of the gas distribution in the combustion chamber 3 of FIG. 5 is as shown in FIG. Thereby, even if the EGR rate is increased, the EGR gas concentration in the vicinity of the spark plug can be suppressed from increasing, so that the EGR rate can be increased while suppressing the deterioration of combustion.

  Further, as in the first embodiment, since the air from the intake passage 10 does not flow into the outer passage 60, a large amount of EGR gas can be recirculated into the combustion chamber 3 even in an operation state in which the air amount increases. Therefore, a high EGR rate can be realized regardless of the required air amount.

Example 3
The first and second embodiments are examples in which the present invention is applied to an internal combustion engine in which one intake port is connected to one cylinder, but this embodiment is an internal combustion in which two intake ports are connected to one cylinder. It is the Example which applied this invention to the engine.

  FIG. 6 is a diagram showing a schematic configuration of an internal combustion engine according to the third embodiment of the present invention. FIG. 6 is a view of the cylinder 2 as seen from above, similarly to FIG. 2 of the first embodiment. As shown in FIG. 6, in this embodiment, two intake ports 5 </ b> A and 5 </ b> B are connected to two openings 13 </ b> A and 13 </ b> B at the top of the combustion chamber 3 for each cylinder.

  The double pipe structure of each of the intake ports 5A and 5B is the same as the intake port 5 of the first embodiment, and the inner passages 7A and 7B and the outer passages 6A and 6B have a coaxial structure. The inner passages 7A and 7B communicate with the intake passage, and air flows into the combustion chamber 3 from the inner passages 7A and 7B.

  Further, the outer passages 6A, 6B communicate with the EGR passage, and EGR gas flows into the combustion chamber 3 from the outer passages 6A, 6B. Fuel injection valves 9A and 9B for injecting fuel are provided in each of the inner passages 7A and 7B.

  In the case where the inner passage and the outer passage have a coaxial structure as in this embodiment, the outer passage is formed between the inner passages 7A and 7B of the intake ports 5A and 5B in a cross section perpendicular to the central axis C of the combustion chamber 3. A part of the passages 6A and 6B is sandwiched (portion indicated by a region 16 in FIG. 6).

  The EGR gas flowing into the combustion chamber 3 from this portion of the outer passages 6A and 6B is mixed substantially uniformly with the air / fuel mixture flowing into the combustion chamber 3 from the inner passages 7A and 7B. Near the upper central axis, a mixture of air, fuel, and EGR gas is localized.

  On the other hand, EGR gas flowing into the combustion chamber 3 from a portion other than the portion indicated by the region 16 of the outer passages 6A and 6B is localized in the vicinity of the inner wall surface and bottom surface of the combustion chamber 3 as in the above-described embodiments. .

  For this reason, in the configuration in which two intake ports 5A and 5B having a double pipe structure in which the inner passage and the outer passage are coaxial as in the present embodiment are connected, the gas distribution formed in the combustion chamber 3 is distributed. As in the first and second embodiments, the gas distribution in the vicinity of the upper central axis in the combustion chamber 3 and the gas in the vicinity of the inner wall surface and bottom surface of the combustion chamber 3 that wraps the gas from the outside and the lower side are layered. However, as shown in FIG. 7, the gas localized in the center of the combustion chamber 3 is a mixture GA + GE of air, fuel, and EGR gas, and the gas localized around the gas is EGR gas.

  Therefore, the gas localized in the vicinity of the spark plug contains EGR gas. This EGR gas is an EGR gas that flows in from a part of the outer passages 6A and 6B in the region 16 of FIG. Most of the EGR gas other than those are localized in the vicinity of the inner wall surface and the bottom surface of the combustion chamber 3 as in the first and second embodiments. Therefore, the influence on the combustibility of the air-fuel mixture is small, and the EGR rate is suppressed while suppressing the deterioration of combustion. Can be sufficiently increased.

  Further, as in the first and second embodiments, since air from the intake passage does not flow into the outer passages 6A and 6B, a sufficient amount of EGR gas can be recirculated even in an operation state in which the air amount increases. Become.

Example 4
This embodiment is also an embodiment in which the present invention is applied to an internal combustion engine in which two intake ports are connected to one cylinder.

  As described in the third embodiment, when the inner passage and the outer passage of each intake port have a coaxial double pipe structure, EGR gas is mixed with the air-fuel mixture localized near the upper central axis of the combustion chamber 3. mixing. In this embodiment, in order to suppress the mixing of EGR gas as much as possible, the inner passage and the outer passage of each intake port do not have a coaxial double pipe structure, and as shown in FIG. The inner passage of the port is eccentric to the other intake port.

  That is, as shown in FIG. 8, the inner passage 7C of the intake port 5C connected to the opening 13A at the top of the combustion chamber 3 is connected to the opening 13B at the top of the combustion chamber 3 with respect to the outer passage 6C of the intake port 5C. Eccentricity is provided near the connected intake port 5D. Similarly, the inner passage 7D of the intake port 5D is provided eccentrically toward the intake port 5C with respect to the outer passage 6D of the intake port 5D.

  As a result, the sections of the outer passages 6C and 6D that are present in the region 16 sandwiched between the inner passages 7C and 7D of the intake ports 5C and 5D in the cross section of the surface perpendicular to the central axis C of the combustion chamber 3 are The size is almost negligible.

  Therefore, the EGR gas mixed in the air-fuel mixture flowing into the combustion chamber 3 from the inner passages 7C, 7D by making the two intake ports 5C, 5D have an eccentric double tube structure as shown in FIG. It becomes possible to reduce the amount of.

  As a result, the same gas distribution in the combustion chamber as in Examples 1 and 2 is formed in which the air-fuel mixture localized near the upper central axis of the combustion chamber 3 does not contain EGR gas, so the EGR rate is increased. However, deterioration of combustion can be suitably suppressed.

  In the present embodiment, the configuration in which the inner passage of each intake port is eccentric toward the other intake port is illustrated, but the direction in which the inner passage is eccentric may be the direction of the central axis C of the combustion chamber 3. In this case, as shown in FIG. 9, the inner passage 7C of the intake port 5C and the inner passage 7D of the intake port 5D are both eccentric toward the center axis C of the combustion chamber 3.

  Even when the double-pipe structure of the two intake ports 5C and 5D has such an eccentric structure, the amount of EGR gas mixed into the air-fuel mixture localized near the upper central axis of the combustion chamber 3 is suitably set. Can be reduced.

Reference Signs List 1 internal combustion engine 2 cylinder 3 combustion chamber 4 piston 5 intake port 6 outer passage 7 inner passage 8 EGR passage 9 fuel injection valve 10 intake passage 11 opening 12 opening
14 Inner passage outer wall surface 15 Intake port inner wall surface 16 Portion of outer passage sandwiched between inner passages of two intake ports Air or air / fuel mixture GE EGR gas GF Fuel C Combustion chamber central axis 50 Intake port 60 Outer passage 70 Inner passage 140 Inner passage outer wall surface 150 Intake port inner wall surface 5A, 5B Intake port 6A, 6B Outer passage 7A, 7B Inner passage 9A, 9B Fuel injection valve 13A, 13B Opening 5C, 5D Intake port 6C, 6D Outer passage 7C 7D inner passage

Claims (5)

An exhaust gas recirculation device for an internal combustion engine comprising an EGR device that recirculates a part of exhaust gas of the internal combustion engine as EGR gas to a combustion chamber,
An intake port communicating with the combustion chamber of the internal combustion engine has a space between an inner passage having an inner diameter smaller than the inner diameter of the intake port, an outer wall surface of the inner passage, and an inner wall surface of the intake port. A double tube structure formed with an outer passage;
An intake passage of the internal combustion engine communicates with the inner passage;
The EGR device recirculates EGR gas to the outer passage,
The outer passage and the inner passage are connected to the combustion chamber ;
The exhaust gas recirculation device for an internal combustion engine, wherein the inner passage, the outer passage, and the combustion chamber have a coaxial structure . An exhaust gas recirculation device for an internal combustion engine comprising an EGR device that recirculates a part of exhaust gas of the internal combustion engine as EGR gas to a combustion chamber,
An intake port communicating with the combustion chamber of the internal combustion engine has a space between an inner passage having an inner diameter smaller than the inner diameter of the intake port, an outer wall surface of the inner passage, and an inner wall surface of the intake port. A double tube structure formed with an outer passage;
An intake passage of the internal combustion engine communicates with the inner passage;
The EGR device recirculates EGR gas to the outer passage,
The outer passage and the inner passage are connected to the combustion chamber ;
Two intake ports having the double pipe structure communicate with the combustion chamber of the internal combustion engine, and the central axis of the inner passage of each intake port is deviated toward the other intake port with respect to the central axis of the outer passage. exhaust gas recirculation system for an internal combustion engine, characterized in that it is heart. An exhaust gas recirculation device for an internal combustion engine comprising an EGR device that recirculates a part of exhaust gas of the internal combustion engine as EGR gas to a combustion chamber,
An intake port communicating with the combustion chamber of the internal combustion engine has a space between an inner passage having an inner diameter smaller than the inner diameter of the intake port, an outer wall surface of the inner passage, and an inner wall surface of the intake port. A double tube structure formed with an outer passage;
An intake passage of the internal combustion engine communicates with the inner passage;
The EGR device recirculates EGR gas to the outer passage,
The outer passage and the inner passage are connected to the combustion chamber ;
Two intake ports having the double pipe structure communicate with the combustion chamber of the internal combustion engine, and the central axis of the inner passage of each intake port is closer to the central axis of the combustion chamber than the central axis of the outer passage. An exhaust gas recirculation device for an internal combustion engine characterized by being eccentric . In any one of Claim 1 to 3,
An exhaust gas recirculation device for an internal combustion engine, comprising a fuel injection valve for injecting fuel into the inner passage. In any one of Claims 1-4,
The exhaust pipe recirculation apparatus for an internal combustion engine, wherein the double pipe structure is formed only in a partial section of the intake port near the connection portion with the combustion chamber.

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