JP6230585B2 - Exhaust gas purification device for internal combustion engine - Google Patents

Description

  The present invention relates to an exhaust emission control device for an internal combustion engine. More specifically, the present invention relates to an exhaust gas purification apparatus for an internal combustion engine including an EGR passage and an EGR cooler.

  2. Description of the Related Art Conventionally, an exhaust gas purification apparatus for an internal combustion engine is known that includes an EGR passage that recirculates part of exhaust gas as EGR gas to an intake passage and an EGR cooler that cools the EGR gas. The EGR cooler is provided in the middle of the EGR passage, and cools EGR gas by exchanging heat with cooling water introduced from an engine cooling circuit for cooling the internal combustion engine.

  The EGR cooler is provided with an inlet and an outlet for cooling water, and an EGR cooling circuit for connecting the inlet and outlet to the engine cooling circuit. This EGR cooling circuit was provided separately from the EGR passage. However, because there are high-temperature parts such as an exhaust manifold around the EGR passage, it was necessary to use an expensive heat-resistant member that was difficult to mold. . Further, since it is necessary to avoid proximity to high temperature parts and to ensure clearance with high temperature parts, it is difficult to reduce the size and packaging and layout are difficult.

  On the other hand, the EGR cooler is required to improve the cooling efficiency of EGR gas. One possible solution is to increase the size of the EGR cooler. In that case, however, the packaging and layout properties are adversely affected in the same manner as described above, which is not a preferable countermeasure.

  Therefore, an EGR in which a double pipe part in which EGR gas is introduced into the inner pipe and cooling water is introduced into the outer pipe is connected upstream of the heat exchange core (main body) having a plurality of tubes through which the cooling water flows. A cooler has been proposed (see, for example, Patent Document 1). According to this EGR cooler, since the EGR gas before being introduced into the heat exchange core can be cooled by the double pipe portion, the cooling efficiency of the EGR gas can be improved as compared with the conventional one, and the EGR cooler can be downsized. Yes.

JP 2013-148334 A

  However, in the EGR cooler of Patent Document 1, since the double pipe portion is provided on the upstream side of the heat exchange core, high-temperature EGR gas before being introduced into the heat exchange core flows through the inner pipe. For this reason, it is necessary to form the double pipe part with a high-temperature heat-resistant material such as steel pipe or cast iron, which is difficult to form compared with aluminum castings, etc., so it is difficult to make it compact and difficult to package and layout. In addition, there is an increase in weight and manufacturing cost. In addition, as a seal member used for the connection between the double pipe part and the heat exchange core, an O-ring other than rubber, a laminated gasket, or a material having high temperature heat resistance such as brazing is required. Became bulky.

  The present invention has been made in view of the above, and an object of the present invention is to provide an exhaust gas purification apparatus for an internal combustion engine that has a cooling efficiency superior to that of the prior art, can be made compact with an inexpensive configuration, and has excellent packaging and layout properties. Is to provide.

  To achieve the above object, the present invention provides an exhaust purification system for an internal combustion engine including an engine cooling circuit (for example, an engine cooling circuit 3 to be described later) in which cooling water for cooling the internal combustion engine (for example, an engine 2 to be described later) circulates. A device (for example, an exhaust purification device 1 to be described later), in which a part of the exhaust from the exhaust passage (for example, an exhaust manifold 22 to be described later) of the internal combustion engine is used as an EGR gas to an intake passage (for example, an intake pipe to be described later). A recirculating EGR passage (for example, an EGR pipe 11 described later) and an EGR cooler (for example, an EGR described later) that is provided in the EGR passage and cools EGR gas by exchanging heat with cooling water introduced from the engine cooling circuit. A cooler 12), an inlet (for example, an inlet 123 described later) and an outlet (for example, an outlet 124 described later) formed in the EGR cooler, and the engine An EGR cooling circuit (for example, an EGR cooling circuit 13 described later) connected to the rejection circuit, and at least a part of the EGR cooling circuit (for example, an exhaust side second cooling pipe 132b described later) In the recirculation direction, the EGR passage and the EGR cooler on the downstream side of the EGR cooler pass through a connection portion (for example, a connection portion 10 to be described later) and extend along the EGR passage. An internal combustion engine that is integrally formed with a separation wall (for example, a separation wall 110 described later), and a gasket (for example, a gasket 100 described later) for sealing cooling water and EGR gas is provided at the connecting portion. An exhaust gas purification device is provided.

In the present invention, at least a part of the EGR cooling circuit is provided so as to extend along the EGR passage through the connection portion between the EGR passage downstream of the EGR cooler and the EGR cooler in the recirculation direction of the EGR gas. The EGR passage and the thermally conductive separation wall are integrally formed. Further, a gasket for sealing the cooling water and the EGR gas is provided at a connection portion between the EGR passage downstream of the EGR cooler and the EGR cooler.
According to the present invention, by forming at least a part of the EGR cooling circuit integrally with the EGR passage, the exhaust emission control device can be made compact, and the packaging layout can be improved. At this time, in order to integrate the EGR passage and the EGR cooling circuit on the downstream side through which the EGR gas that has already been sufficiently cooled after passing through the EGR cooler is integrated, the EGR passage and the EGR cooling circuit are made of an inexpensive material such as an aluminum casting. Can reduce the weight and manufacturing cost.
Further, by forming at least a part of the EGR cooling circuit integrally with the EGR passage through the thermally conductive separation wall, the EGR gas flowing through the EGR passage can be further cooled by the cooling water flowing through the EGR cooling circuit. Therefore, the cooling efficiency of EGR gas can be improved.
In addition, a gasket for sealing cooling water and EGR gas is provided at the connection portion between the EGR passage downstream of the EGR cooler and the EGR cooler, and the EGR gas passing through this connection portion is already in the EGR cooler. Since the EGR gas is sufficiently cooled, high-temperature heat resistance is not essential as a constituent member of the gasket, and an inexpensive member can be used.
Therefore, according to the present invention, it is possible to provide an exhaust gas purification apparatus for an internal combustion engine that has a cooling efficiency superior to that of the prior art, can be made compact with an inexpensive configuration, and has excellent packaging and layout properties.

  The EGR cooling circuit has a cross-sectional shape in a direction perpendicular to a central axis direction of the EGR cooling circuit (for example, a central axis X described later) in a portion integrally formed with the EGR passage via the separation wall. A length in a direction substantially parallel to the separation wall (for example, a length L2 to be described later) is longer than a length in a direction substantially perpendicular to the separation wall (for example, a length L1 to be described later). An elliptical shape or a substantially rectangular shape is preferable.

In the present invention, the cross-sectional shape in the direction perpendicular to the central axis direction of the EGR cooling circuit in the portion integrally formed with the EGR passage via the separation wall is an elliptical shape or a substantially rectangular shape. More specifically, the cross-sectional shape is an ellipse or a substantially rectangular shape in which the length in the direction substantially parallel to the separation wall is longer than the length in the direction substantially perpendicular to the separation wall.
Thereby, the contact area of the EGR passage and the EGR cooling circuit through the thermally conductive separation wall can be increased. Therefore, the heat exchange efficiency between the EGR gas flowing through the EGR passage and the cooling water flowing through the EGR cooling circuit can be increased via the thermally conductive separation wall, and cooling of the EGR gas flowing through the EGR passage can be performed. The efficiency can be further improved.

  The connection portion of the EGR cooler is provided with an EGR cooler flange portion (for example, an EGR cooler flange portion 121 described later) having a flange surface (for example, a flange surface 121f described later), and is connected to the connection portion of the EGR passage. Is provided with an EGR passage flange portion (for example, an EGR pipe flange portion 111 described later) having a flange surface (for example, a flange surface 111f described later), and the EGR cooler flange portion, the EGR passage flange portion, and the gasket include , EGR holes through which EGR gas passes (for example, EGR holes 111a, 121a, and 100a described later) and cooling water holes through which cooling water passes (for example, cooling water holes 111b, 121b, and 100b, described later), respectively, at corresponding positions. ), And is formed between the EGR cooler flange portion and the EGR passage flange portion. Between the EGR hole and the cooling water hole in at least one of the flange surfaces, the EGR hole and the cooling water hole are partitioned and extend to the outer edge of the flange surface and open to the outside (for example, described later) The grooves 111g and 121g) are preferably formed.

In the present invention, an EGR hole through which EGR gas passes and a cooling water hole through which cooling water passes are formed at positions corresponding to the EGR cooler flange portion, the EGR passage flange portion, and the gasket in the connection portion described above. . Further, the EGR hole and the cooling water hole are defined between the EGR hole and the cooling water hole in at least one of the EGR cooler flange portion and the EGR passage flange portion, and the EGR hole and the cooling water hole are extended to the outer edge of the flange surface and opened to the outside. Grooves to be formed are formed.
As a result, it is possible to reliably prevent the cooling water flowing through the EGR cooling circuit from being mixed into the EGR passage flowing through the EGR passage at the above-described connecting portion, and reliably generating a water hammer or misfire of the internal combustion engine. Can be avoided. In addition, it is possible to reliably avoid the occurrence of problems due to the EGR gas flowing through the EGR passage being mixed into the EGR cooling circuit.

  According to the present invention, it is possible to provide an exhaust emission control device for an internal combustion engine that has a cooling efficiency superior to that of the prior art, can be made compact with an inexpensive configuration, and has excellent packaging and layout properties.

1 is a front view of an exhaust gas purification apparatus for an internal combustion engine according to an embodiment of the present invention. It is a side view of the exhaust emission control device of the internal combustion engine according to the embodiment. It is a disassembled perspective view of the exhaust gas purification apparatus of the internal combustion engine which concerns on the said embodiment. FIG. 4 is a sectional view taken along line AA in FIG. 3. FIG. 4 is a sectional view taken along line BB in FIG. 3. It is a figure which shows the EGR pipe flange part which concerns on the said embodiment. It is a figure which shows the EGR cooler flange part which concerns on the said embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a front view of an exhaust emission control device 1 for an internal combustion engine according to an embodiment of the present invention. FIG. 2 is a side view of the exhaust gas purification apparatus 1 for an internal combustion engine according to the present embodiment. FIG. 3 is an exploded perspective view of the exhaust gas purification apparatus 1 for an internal combustion engine according to the present embodiment. In FIGS. 1 and 2, U represents the upper side, LW represents the lower side, R represents the right direction viewed from the driver, L represents the left direction viewed from the driver, Fr represents the front of the vehicle, and Rr represents the rear of the vehicle.

As shown in FIGS. 1 and 2, the exhaust emission control device 1 of the present embodiment is disposed on the vehicle front side of an internal combustion engine (hereinafter referred to as “engine”) 2.
As shown in FIG. 2, the engine 2 is a supercharged engine including a turbocharger 21 including a turbine 211 and a compressor 212 (the turbocharger 21 is not shown in FIG. 1). The engine 2 includes an engine cooling circuit 3 in which cooling water for cooling the engine 2 circulates.
The engine cooling circuit 3 includes a cooling pump (not shown) provided in the cylinder block 20 and a water pump 31 for circulating cooling water in the engine cooling circuit 3.

  The exhaust emission control device 1 includes an EGR pipe 11, an EGR cooler 12, and an EGR cooling circuit 13.

  One end side of the EGR pipe 11 is connected to the downstream side of the EGR cooler 12 described later (downstream side in the EGR gas recirculation direction), and the other end side is connected to an intake pipe (not shown). The EGR pipe 11 recirculates a part of the exhaust gas flowing through the exhaust manifold 22 constituting the exhaust passage into an intake pipe (not shown) as EGR gas. More specifically, the EGR pipe 11 of the present embodiment constitutes a high-pressure EGR passage that extracts a part of the exhaust from the exhaust manifold 22 located on the upstream side of the turbine 211 constituting the turbocharger 21 and returns it to an intake pipe (not shown). To do.

  One end side of the EGR cooler 12 is connected to the exhaust manifold 22, and the other end side is connected to the upstream side of the above-described EGR pipe 11 (upstream side in the EGR gas recirculation direction). The EGR cooler 12 cools the EGR gas by exchanging heat with the cooling water introduced from the engine cooling circuit 3 described above. As shown in FIGS. 1 and 3, the EGR cooler 12 is provided on the upstream side (upstream side in the EGR gas recirculation direction) and on the downstream side (downstream side in the EGR gas recirculation direction). And a heat exchange core part 122.

The connecting portion 120 is configured by a connecting pipe that connects the downstream side of the exhaust manifold 22 and the heat exchange core portion 122. The connecting portion 120 is greatly bent downward from the exhaust manifold 22 side, then extends downward through the bellows portion 120a, and is connected to the heat exchange core portion 122.
The heat exchange core 122 includes a substantially rectangular parallelepiped case 122a that is long in the left-right direction, an inlet 123 that is provided upstream of the case 122a (upstream in the EGR gas recirculation direction) and into which cooling water is introduced, and a case 122a. , Which is provided on the downstream side (downstream of the EGR gas recirculation direction) and from which the cooling water is discharged (see FIG. 3), is accommodated in the case 122a, and connects the inlet 123 and the outlet 124. A cooling water pipe (not shown).
With the above configuration, the EGR cooler 12 can cool a part of the exhaust gas (EGR gas) introduced from the exhaust manifold 22 by the connecting portion 120 by the heat exchange core portion 122.

The EGR cooling circuit 13 connects the aforementioned inlet 123 and outlet 124 formed in the heat exchange core 122 of the EGR cooler 12 and the aforementioned engine cooling circuit 3. The EGR cooling circuit 13 of the present embodiment includes an introduction-side cooling pipe 131 that connects the engine cooling circuit 3 and the introduction port 123 of the heat exchange core unit 122, the discharge port 124 of the heat exchange core unit 122, and the engine. And a discharge side cooling pipe 132 connected to the cooling circuit 3.
The discharge side cooling pipe 132 includes a discharge side first cooling pipe 132a, a discharge side second cooling pipe 132b, which will be described later, and a discharge side third cooling pipe 132c in this order from the discharge port 124 side. .

  Here, since the pressure of the cooling water flowing through the EGR cooling circuit 13 and the EGR cooler 12 is lower than the pressure of the cooling water flowing through the cylinder block 20, it is difficult to directly return the cooling water into the cylinder block 20. For this reason, conventionally, the discharge side cooling pipe 132 cannot be directly connected to the cylinder block 20 and has to be provided around the cylinder block 20. Therefore, it is necessary to ensure clearance with a large number of high-temperature peripheral parts. In the present embodiment, this has been avoided by integrally forming with the EGR pipe 11 which will be described later.

Therefore, the EGR cooling circuit 13 will be described in more detail with reference to FIGS. 4 is a cross-sectional view taken along the line AA in FIG. 3, and FIG. 5 is a cross-sectional view taken along the line BB in FIG.
As shown in FIGS. 3 and 4, in the EGR cooling circuit 13 of the present embodiment, at least a part of the discharge side cooling pipe 132, specifically, the discharge side second cooling pipe 132 b includes the EGR pipe 11 and the EGR cooler 12. Is extended along the EGR pipe 11 through the connecting portion 10 and is integrally formed with the EGR pipe 11 via a thermally conductive separation wall 110. The integrally formed EGR pipe 11 and discharge side second cooling pipe 132b are formed of an aluminum casting.

  Further, as shown in FIG. 5, the discharge-side second cooling pipe 132b integrally formed with the EGR pipe 11 via the separation wall 110 is in the direction of the central axis X of the discharge-side second cooling pipe 132b (the flow direction of the cooling water). ) In the direction perpendicular to the separation wall 110 is longer than the length L1 in the direction substantially perpendicular to the separation wall 110. The length L2 in the direction substantially parallel to the separation wall 110 is longer. Is formed.

Returning to FIG. 3, the connecting portion 10 between the EGR pipe 11 and the EGR cooler 12 is provided with a gasket 100 for sealing the cooling water and the EGR gas. That is, the EGR pipe 11 and the EGR cooler 12 are connected to each other through flanges 100 described later.
In addition, the gasket 100 of this embodiment is comprised with the rubber-made gasket of 1 sheet. In addition, the gasket 100 is provided with an EGR hole 100a through which EGR gas passes and a cooling water hole 100b through which cooling water passes at predetermined positions, as will be described later, and an EGR pipe flange portion 111 and an EGR cooler flange. Three fastening holes 100c, 100d, and 100e are formed through which fastening members for connecting to the portion 121 are inserted.

The structure of the connecting portion 10 between the EGR pipe 11 and the EGR cooler 12 will be described in more detail with reference to FIGS.
Here, FIG. 6 is a view showing the EGR pipe flange portion 111 provided in the connection portion 10 of the EGR pipe 11. FIG. 7 is a view showing the EGR cooler flange portion 121 provided in the connection portion 10 of the EGR cooler 12. 6 and 7 are views in which each flange portion is viewed from a direction orthogonal to each flange surface.

  As shown in FIG. 6, the EGR pipe flange portion 111 has an EGR hole 111a and a cooling water hole 111b. The EGR hole 111a and the cooling water hole 111b are formed at positions corresponding to EGR hole 121a and 100a and cooling water holes 121b and 100b formed in the EGR cooler flange 121 and the gasket 100, respectively, which will be described later. That is, when the EGR pipe flange portion 111 and the EGR cooler flange portion 121 are connected via the gasket 100, the EGR hole and the cooling water hole formed in the EGR pipe flange portion 111, the gasket 100, and the EGR cooler flange portion 121, respectively. As a result of the connection, an EGR gas channel and a cooling water channel are formed.

The EGR gas flowing through the EGR pipe 11 passes through the EGR hole 111a. The cooling water flowing through the EGR cooling circuit 13 passes through the cooling water hole 111b.
The EGR pipe flange portion 111 is formed with three fastening holes 111c, 111d, and 111e through which a fastening member for connecting to the EGR cooler flange portion 121 through the gasket 100 is inserted.

  Further, a groove 111g that partitions the EGR hole 111a and the cooling water hole 111b is formed between the EGR hole 111a and the cooling water hole 111b on the flange surface 111f of the EGR pipe flange portion 111. The groove 111g extends to both outer edges of the flange surface 111f and opens to the outside. That is, the groove 111g has openings 111h and 111i that open to the outside at both ends in the extending direction. Thereby, even if the cooling water flows into the groove 111g, the cooling water flows through the groove 111g and is discharged to the outside through the openings 111h and 111i. As a result, a situation in which the cooling water passes through the EGR hole 111a and enters the EGR pipe 11 is avoided. Moreover, the situation where EGR gas passes through the cooling water hole 111b and enters the EGR cooling circuit 13 is avoided.

Similarly, as shown in FIG. 7, the EGR cooler flange portion 121 has an EGR hole 121a and a cooling water hole 121b formed at the positions described above.
The EGR cooler flange portion 121 is also formed with three fastening holes 121c, 121d, and 121e through which fastening members for connecting to the EGR pipe flange portion 111 through the gasket 100 are inserted.

  Similarly to the EGR pipe flange portion 111, the flange surface 121f of the EGR cooler flange portion 121 has a groove 121g that partitions the EGR hole 121a and the cooling water hole 121b between the EGR hole 121a and the cooling water hole 121b. Is formed. The groove 121g extends to both outer edges of the flange surface 121f and opens to the outside. That is, the groove 121g has openings 121h and 121i that open to the outside at both ends in the extending direction. The operation of the groove 121g is the same as that of the groove 111g described above.

According to this embodiment, the following effects are exhibited.
In the present embodiment, at least a part of the EGR cooling circuit 13, specifically, the discharge-side second cooling pipe 132 b is located on the downstream side of the EGR cooler 12 in the EGR gas recirculation direction, and the EGR pipe 11 and the EGR cooler 12. The EGR tube 11 is provided so as to extend along the EGR tube 11 through the connecting portion 10, and is integrally formed with the EGR tube 11 via the thermally conductive separation wall 110. Further, a gasket 100 for sealing cooling water and EGR gas is provided at the connection portion 10 between the EGR pipe 11 and the EGR cooler 12 on the downstream side of the EGR cooler 12.
According to this embodiment, at least a part of the EGR cooling circuit 13, specifically, the discharge-side second cooling pipe 132 b is formed integrally with the EGR pipe 11, so that the exhaust purification device 1 can be made compact. Layout can be improved. At this time, in order to integrate the EGR pipe 11 and the EGR cooling circuit 13 on the downstream side through which the EGR gas that has passed through the EGR cooler 12 and has been sufficiently cooled flows, the EGR pipe 11 and the EGR cooling circuit 13 are made of an aluminum casting. The material can be molded with an inexpensive material such as a material, and the weight and manufacturing cost can be reduced.
Further, at least a part of the EGR cooling circuit 13, specifically, the discharge-side second cooling pipe 132 b is integrally formed with the EGR pipe 11 through the thermally conductive separation wall 110, thereby circulating the EGR cooling circuit 13. Since the EGR gas flowing through the EGR pipe 11 can be further cooled by the cooling water to be cooled, the cooling efficiency of the EGR gas can be improved.
In addition, a gasket 100 for sealing cooling water and EGR gas is provided at the connection portion 10 between the EGR pipe 11 and the EGR cooler 12 downstream of the EGR cooler 12. Since the gas is EGR gas that has already been sufficiently cooled by the EGR cooler 12, high-temperature heat resistance is not essential as a constituent member of the gasket 100, and an inexpensive member such as rubber can be used.
Therefore, according to the present embodiment, it is possible to provide an exhaust gas purification apparatus 1 for an internal combustion engine that has a cooling efficiency superior to that of the prior art, can be made compact with an inexpensive configuration, and has excellent packaging and layout properties.

Here, the effect that an inexpensive rubber member can be used as a constituent member of the gasket 100 will be described below.
In order to investigate the cooling efficiency of the EGR gas by the EGR cooler 12 of the present embodiment, when the EGR gas having a predetermined temperature and flow rate is used, the temperature of the EGR gas passing through the inlet side of the EGR cooler 12 is 400 ° C. It has been confirmed that the temperature of the EGR gas passing through the outlet side of the EGR cooler 12 is 150 ° C. or lower. On the other hand, for the double pipe provided on the upstream side of the EGR cooler of Patent Document 1 described above, when the temperature of the EGR gas passing through the inlet of the double pipe is 400 ° C., the double pipe The temperature of the EGR gas passing through the outlet of the section is assumed to be 250 ° C. or higher.
From these, it can be seen that high temperature EGR gas passes through the connecting portion between the outlet of the conventional double tube portion and the heat exchange core, and as a seal member used for such connecting portion, an O-ring other than rubber or a laminated gasket is used. It can be seen that a material having high temperature heat resistance such as brazing is necessary. On the other hand, since the temperature of the EGR gas passing through the connecting portion 10 between the downstream side of the EGR cooler 12 and the EGR pipe 11 of this embodiment is sufficiently lowered, a rubber gasket can be used. I understand that there is. Therefore, the above-described effect can be obtained.

In the present embodiment, the discharge-side second cooling pipe 132b integrally formed with the EGR pipe 11 via the separation wall 110 has a cross-sectional shape perpendicular to the central axis X direction of the EGR cooling circuit 13 as an elliptical shape. It was. More specifically, the cross-sectional shape is an elliptical shape in which the length L2 in the direction substantially parallel to the separation wall 110 is longer than the length L1 in the direction substantially perpendicular to the separation wall 110.
Thereby, the contact area of the EGR pipe 11 and the EGR cooling circuit 13 through the thermally conductive separation wall 110 can be increased. Therefore, the heat exchange efficiency between the EGR gas that flows through the EGR pipe 11 and the cooling water that flows through the EGR cooling circuit 13 can be increased via the heat conductive separation wall 110, and the EGR pipe 11 flows. The cooling efficiency of EGR gas can be further improved.

Further, in the present embodiment, EGR holes 111a, 121a, 100a through which EGR gas passes at positions corresponding to the EGR cooler flange portion 121 and the EGR pipe flange portion 111 and the gasket 100 in the connection portion 10 described above, Cooling water holes 111b, 121b, and 100b through which the cooling water passes were formed. Further, between the EGR holes 111a and 121a and the cooling water holes 111b and 121b in the flange surfaces 111f and 121f of the EGR cooler flange part 121 and the EGR pipe flange part 111, the EGR holes 111a and 121a and the cooling water holes 111b and 121b are provided. And grooves 111g and 121g that extend to both outer edges of the flange surfaces 111f and 121f and open to the outside are formed.
As a result, it is possible to reliably avoid the cooling water flowing through the EGR cooling circuit 13 from being mixed into the EGR pipe 11 flowing through the EGR pipe 11 in the connection portion 10 described above, and the occurrence of a water hammer or the misfire of the engine 2 Etc. can be avoided reliably. In addition, it is possible to reliably avoid the occurrence of problems due to the EGR gas flowing through the EGR pipe 11 being mixed into the EGR cooling circuit 13.

It should be noted that the present invention is not limited to the above-described embodiment, and modifications and improvements within the scope that can achieve the object of the present invention are included in the present invention.
In the said embodiment, the flow direction of the cooling water which distribute | circulates the inside of the EGR cooling circuit 13 is not limited, It is good also as a structure which reversely flows an upstream side and a downstream side, and a cooling water distribute | circulates in the reverse direction. Even in this case, the same cooling efficiency can be obtained.

  Moreover, in the said embodiment, although the cross-sectional shape of the direction perpendicular | vertical with respect to the central-axis X direction in the discharge side 2nd cooling pipe 132b integrally formed with the EGR pipe | tube 11 was made into elliptical shape, it is not limited to this. For example, the cross-sectional shape may be a rectangular shape in which the length L2 in the direction substantially parallel to the separation wall 110 is longer than the length L1 in the direction substantially perpendicular to the separation wall 110.

DESCRIPTION OF SYMBOLS 1 ... Exhaust gas purification device 2 ... Engine (internal combustion engine)
3 ... Engine cooling circuit 10 ... Connection part 11 ... EGR pipe (EGR passage)
12 ... EGR cooler 13 ... EGR cooling circuit 22 ... Exhaust manifold (exhaust passage)
DESCRIPTION OF SYMBOLS 100 ... Gasket 110 ... Separation wall 111 ... EGR pipe flange part (EGR passage flange part)
111a, 121a, 100a ... EGR hole 111b, 121b, 100b ... cooling water hole 111f, 121f ... flange surface 111g, 121g ... groove 121 ... EGR cooler flange part 123 ... introduction port 124 ... discharge port X ... central axis L1 ... separation wall Length in a direction substantially perpendicular to L2 ... Length in a direction substantially parallel to the separation wall

Claims (3)

An exhaust purification device for an internal combustion engine comprising an engine cooling circuit through which cooling water for cooling the internal combustion engine circulates,
An EGR passage that recirculates a portion of the exhaust from the exhaust passage of the internal combustion engine to the intake passage as EGR gas;
An EGR cooler that is provided in the EGR passage and cools the EGR gas by exchanging heat with the cooling water introduced from the engine cooling circuit;
An EGR cooling circuit that connects the cooling water inlet and outlet formed in the EGR cooler and the engine cooling circuit;
At least a part of the EGR cooling circuit extends along the EGR passage through a connection portion between the EGR passage and the EGR cooler downstream of the EGR cooler in the recirculation direction of EGR gas, and the EGR passage. It is integrally formed through a passage and a thermally conductive separation wall,
An exhaust gas purification apparatus for an internal combustion engine, wherein the connection portion is provided with a gasket for sealing cooling water and EGR gas.   In the EGR cooling circuit, a cross-sectional shape in a direction perpendicular to the central axis direction of the EGR cooling circuit in a portion integrally formed with the EGR passage through the separation wall is substantially perpendicular to the separation wall. 2. The exhaust emission control device for an internal combustion engine according to claim 1, wherein the length in the direction substantially parallel to the separation wall is longer than the length in the direction. The connection portion of the EGR cooler is provided with an EGR cooler flange portion having a flange surface,
The connection portion of the EGR passage is provided with an EGR passage flange portion having a flange surface,
In the EGR cooler flange portion, the EGR passage flange portion, and the gasket, an EGR hole through which EGR gas passes and a cooling water hole through which cooling water passes are formed at corresponding positions, respectively.
Between the EGR hole and the cooling water hole in at least one of the EGR cooler flange portion and the EGR passage flange portion, the EGR hole and the cooling water hole are partitioned, and the flange surface The exhaust gas purification apparatus for an internal combustion engine according to claim 1 or 2, wherein a groove extending to the outer edge and opening to the outside is formed.

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