JP5413651B2 - Exhaust gas recirculation device - Google Patents

Description

  The present invention relates to an exhaust gas recirculation device that recirculates exhaust gas to a combustion chamber in an internal combustion engine such as an automobile.

  In internal combustion engines such as automobiles, Patent Documents 1 to 3 describe techniques for returning blow-by gas and exhaust gas to a combustion chamber.

Patent Document 1 describes a blow-by gas reduction (PCV) device in which blow-by gas in a crankcase is circulated to a combustion chamber of each cylinder and burned.
In this device, a groove is formed in the wall of the cylinder head, and the blow-by gas that has circulated through the groove is introduced into the intake passage of the intake manifold through a hole provided in the gasket sandwiched between the cylinder head and the intake manifold. Is done.

Patent Document 2 describes an exhaust gas recirculation device for an internal combustion engine. The exhaust gas recirculation apparatus has a structure in which recirculated EGR gas (recirculation exhaust gas) is extracted from, for example, an exhaust port of a cylinder head, passes through an EGR valve, and is discharged to an intake port. In the exhaust gas recirculation apparatus, a part of the exhaust gas is recirculated to the combustion chamber, so that the combustion temperature can be lowered and the generation amount of NOx can be reduced.
In the exhaust gas recirculation device of Patent Document 2, a resin intake manifold is connected to a cylinder head via a metal spacer and a metal gasket. In the cylinder head, an EGR gas intake passage and an EGR gas discharge passage are formed as grooves through which the EGR gas passes.
The gasket is formed with an EGR gas common communication port and an EGR gas branch communication port. The metal spacer is formed with an EGR gas branch passage communicating with the EGR gas common communication port and the EGR gas branch communication port on the joint surface with the gasket.
The EGR gas sucked from the exhaust port passes through the EGR gas suction passage, the EGR gas common communication port, the EGR gas branch passage, and the EGR gas branch communication port, flows through the EGR gas discharge passage, and is discharged to the suction port. It is configured.

Patent Document 3 discloses a gas supply member (EGR plate) formed with a common passage to which an exhaust passage from an exhaust system is connected and a distribution passage for distributing EGR gas supplied from the common passage to intake ports of each cylinder. ) Is provided for an engine exhaust gas recirculation device provided in a cylinder head.
The cylinder head is provided with a communication passage that communicates with the intake port, and the distribution passage of the EGR plate communicates with the communication passage, whereby EGR gas is discharged to the intake port.

JP 2005-155454 A JP 2000-8968 A JP 2005-98164 A

  In the PCV device of Patent Document 1, a groove is formed in the wall of the cylinder head to provide a blow-by gas passage. However, in the configuration in which the groove portion, which is a gas passage, is formed on the cylinder head side, the shape of the cylinder head becomes complicated and the manufacturing cost increases.

In the apparatus of Patent Document 2, a metal spacer having a gas passage formed between the intake manifold and the cylinder head is disposed. This is because the EGR gas usually becomes high temperature, and when the resin intake manifold comes into contact with the high temperature EGR gas, the intake manifold deteriorates, so that the heat damage from the EGR gas does not reach the intake manifold. It is. Moreover, in the apparatus of Patent Document 3, an EGR plate having a gas passage formed on the cylinder head side is disposed. The metal spacer and the EGR plate are usually made of a metal having excellent heat resistance. However, such a structure is costly and requires an excessive space for the metal spacer and the EGR plate. It was.

  By the way, the resin intake manifold is formed by incorporating a technique (vibration welding) in which the resins are melted and welded by frictional heat generated at the joint interface by friction between the resins. If the intake manifold is to be formed of a heat resistant resin, it is difficult to weld the resins together because the heat resistant resin is difficult to melt by friction. Furthermore, heat resistant resins are expensive. Therefore, it is not realistic to form the entire intake manifold from a heat resistant resin.

  Accordingly, an object of the present invention is to provide an exhaust gas recirculation device for an internal combustion engine that can suppress the manufacturing cost with a simple configuration.

In order to achieve the above object, the first feature of the exhaust gas recirculation apparatus for an internal combustion engine according to the present invention is that a wall portion of the cylinder head of the intake manifold is compared with a resin intake manifold attached to the outside of the cylinder head. Provided with a groove-like space provided on the mounting surface opposed to
The groove-shaped space has a half pipe embedded in the intake manifold so as to be in close contact with the wall of the cylinder head, while opening to the wall of the cylinder head.
The half pipe is made of a material having heat resistance than the intake manifold, and connects the exhaust port and the intake port of the cylinder head to allow the exhaust gas from the exhaust port to flow into the intake port. It is in the point used as a passage.

  Conventionally, a recirculation exhaust gas passage through which high-temperature recirculation exhaust gas (hereinafter referred to as EGR gas) flows is a separate member provided between the cylinder head and the intake manifold in order to prevent heat damage to the intake manifold. It was not formed on the intake manifold side by forming it on the spacer or on the cylinder head side. However, in the present invention, the recirculation exhaust gas passage is formed on the intake manifold side. Since no spacer is provided between the cylinder head and the intake manifold as described above, the gasket provided between the cylinder head and the intake manifold can be simplified, and the exhaust gas recirculation device can be saved and simplified accordingly. can do. When the spacer is not provided in this way, the intake manifold can be directly connected to the cylinder head, and therefore the work of assembling the intake manifold to the cylinder head is facilitated.

If the recirculation exhaust gas passage is disposed on the cylinder head side, processing for attaching the recirculation exhaust gas passage to the cylinder head is required. In order to perform such processing on a metal cylinder head, the mold for casting the cylinder head is complicated, but if the shape of the mold is complicated, the cost increases, which is not preferable. However, in the present invention, since the recirculation exhaust gas passage is disposed on the side of the resin intake manifold that is easier to process than the cylinder head, manufacture of the exhaust recirculation device is facilitated. In addition, since the process for attaching the recirculation exhaust gas passage to the cylinder head is not performed, the shape of the cylinder head can be simplified.
Furthermore, in the present invention, since the intake manifold is not formed of heat-resistant resin, and only the components of the recirculation exhaust gas passage are formed of heat-resistant material, the members using expensive heat-resistant material can be minimized. Cost can be suppressed.

Moreover, according to this structure, EGR gas can be distribute | circulated in the groove-shaped space enclosed by the groove part of the aspect which provided the attachment surface of the intake manifold concavely, and the wall part of a cylinder head. Therefore, it is possible to easily secure a space for circulating the EGR gas by joining the cylinder head and the intake manifold.

Further , according to this configuration, the groove-shaped space is formed by simply fitting a half pipe manufactured separately from the intake manifold into the intake manifold. Therefore, the degree of freedom in designing the shape of the recirculation exhaust gas passage, such as the flow path diameter and the cross-sectional shape, is increased. Therefore, the recirculation exhaust gas passage can be easily formed.

Another characteristic configuration of the exhaust gas recirculation apparatus for an internal combustion engine according to the present invention is that an air layer is provided between the intake manifold and the outer peripheral surface of the half pipe.

  According to this configuration, when high-temperature EGR gas flows through the recirculation exhaust gas passage, heat transmitted from the half pipe to the intake manifold side can be easily blocked by the air layer. Therefore, the heat damage that EGR gas exerts on the intake manifold can be suppressed.

In another feature of the exhaust gas recirculation apparatus for an internal combustion engine according to the present invention, a gasket member made of a heat resistant resin for sealing a connection portion between the intake port of the cylinder head and the intake manifold is connected to the half pipe. In the point.

  In order to prevent EGR gas from leaking at the connecting part between the cylinder head and the intake manifold, any gasket is necessary. With this configuration, the gasket is used when setting the half pipe to the intake manifold. Members can also be incorporated at the same time. Therefore, the number of parts at the time of assembly is reduced, and the number of installation steps of the intake manifold can be reduced.

Another feature of the exhaust gas recirculation apparatus for an internal combustion engine according to the present invention is that the recirculation exhaust gas passage is formed in a flange portion connected to the cylinder head in the intake manifold.

  According to this configuration, since the recirculation exhaust gas passage can be arranged using the width of the flange portion, the space of the exhaust recirculation device can be saved.

It is the schematic which shows the exhaust gas recirculation apparatus of the internal combustion engine of this invention. FIG. 3 is a schematic cross-sectional view of a recirculated exhaust gas passage and a flange portion of an intake manifold. It is sectional drawing of the III-III line of FIG. It is a cross-sectional schematic diagram of the recirculation exhaust gas passage. It is a disassembled perspective view of the recirculation | reflux exhaust gas path provided in the flange part of the intake manifold.

Embodiments of the present invention will be described below with reference to the drawings.
The exhaust gas recirculation device of the present invention is a device that recirculates exhaust gas to a combustion chamber in an internal combustion engine such as an automobile. As shown in FIGS. 1 to 5, in the present embodiment, an example of an in-line three-cylinder internal combustion engine is shown as the internal combustion engine Y in which the exhaust gas recirculation device X is installed, but of course, the configuration of the internal combustion engine is limited to this. It is not a thing.

  The exhaust gas recirculation device X is formed of a material having heat resistance from the intake manifold 1 for the resin intake manifold 1 attached to the outside of the cylinder head 2, and connects the exhaust port 4 and the intake port 5 of the cylinder head 2. A recirculation exhaust gas passage 6 is provided for allowing the exhaust gas from the exhaust port 4 to flow into the intake port 5.

  The cylinder head 2 is formed with an exhaust port 4 for exhausting exhaust gas from the combustion chamber and an intake port 5. The intake manifold 1 has three intake passages 1a, 1b, and 1c. A flange portion 1 d provided at the end of the intake manifold 1 is fastened and connected to the connection surface 2 a of the cylinder head 2. The cylinder head 2 is made of a metal material such as aluminum. The intake manifold 1 is made of a polyamide resin such as PA6. Normally, when the intake manifold 1 is molded from resin, it is manufactured by a vibration welding technique. Since the heat resistant resin is expensive and the vibration welding technique cannot be adopted, it is not suitable as a material for forming the intake manifold 1.

  Since the recirculated exhaust gas (EGR gas) has a high temperature of about 150 ° C., the recirculated exhaust gas passage 6 is formed of a material having heat resistance from the intake manifold 1. When the recirculation exhaust gas passage 6 is formed of a plurality of members, all of these members are made of a heat resistant material. Examples of the heat resistant material include a metal material such as aluminum and a heat resistant resin such as PPS and PEEK, but are not limited thereto.

  As shown in FIG. 1, the EGR gas is taken out from the exhaust port 4 of the cylinder head 2, passes through the upstream passage 7 a of the EGR gas suction passage 7, and flows into the EGR valve 3. The EGR valve 3 is attached to the connection surface 2a and controls the amount of EGR gas flowing through the EGR gas intake passage 7 according to the engine operating state. The EGR gas flowing down the EGR valve 3 flows into the recirculated exhaust gas passage 6 through the downstream passage 7 b of the EGR gas intake passage 7. The recirculation exhaust gas passage 6 of the present embodiment includes three branch passages 6a to 6c, which are connected to the suction ports 5a to 5c, respectively. Thereby, EGR gas which flowed out from branch passages 6a-6c is discharged to suction ports 5a-5c, respectively.

  In the present invention, the recirculation exhaust gas passage 6 is formed on the intake manifold 1 side. Since no spacer is provided between the cylinder head 2 and the intake manifold 1 in this way, at least one of the gaskets attached to both surfaces of the spacer together with the spacer can be omitted, and the exhaust gas recirculation device X can be saved accordingly. Space and simplification can be achieved. When the spacer is not provided in this way, the intake manifold 1 can be directly connected to the cylinder head 2, and therefore the work of assembling the intake manifold 1 to the cylinder head 2 is facilitated.

Further, in the present invention, the recirculation exhaust gas passage 6 is disposed on the side of the resin intake manifold 1 that is easier to process than the cylinder head 2, so that the recirculation exhaust gas passage 6 is not attached to the cylinder head 2. Therefore, the shape of the cylinder head 2 can be simplified.
Furthermore, in the present invention, since the intake manifold 1 is not formed of heat-resistant resin, but only the constituent members of the recirculation exhaust gas passage 6 are formed of heat-resistant material, the cost can be suppressed.

  In the present embodiment, a groove-like space S provided in the mounting surface 1A facing the wall 2b of the cylinder head 2 in the intake manifold 1 is used as the recirculation exhaust gas passage 6 (FIGS. 2 to 5).

  As a result, the EGR gas can be circulated through the groove portion 1B having a concave mounting surface 1A of the intake manifold 1 and the groove-like space S surrounded by the wall portion 2b of the cylinder head 2. If it is this structure, the space which distribute | circulates EGR gas only by joining the cylinder head 2 and the intake manifold 1 can be ensured easily.

The groove-shaped space S may be formed only by the groove portion 1B of the intake manifold 1, for example. In that case, the surface of the groove portion 1B is molded in two colors with another heat-resistant resin with respect to the intake manifold 1, or a metal layer is molded to form a heat-resistant reflux exhaust gas passage 6 integrally with the intake manifold 1. To do. Alternatively, the reflux exhaust gas passage 6 may be formed by providing a separate heat-resistant member for the intake manifold 1. In the present embodiment, the groove-like space S is formed by the half pipe 10 embedded in the intake manifold 1 so as to open to the wall 2b side of the cylinder head 2 and to be in close contact with the wall 2b of the cylinder head 2. An example is shown.
The half pipe 10 is a bowl-shaped member that is opened with a part of the cross section of the pipe being cut off. In the present embodiment, the half pipe 10 is fitted into the groove portion 1 </ b> B of the intake manifold 1 in a state where the end portion is in contact with the wall portion 2 b of the cylinder head 2. Since the half pipe 10 is a constituent member of the recirculation exhaust gas passage 6, it is made of a heat resistant material. In addition, although the other structural member of the recirculation | reflux exhaust gas channel | path 6 is the cylinder head 2, this is also comprised with the metal material which has heat resistance.
In this configuration, the groove-shaped space S is formed by simply fitting the half pipe 10 manufactured separately from the intake manifold 1 into the groove 1B. Therefore, the degree of freedom in designing the shape of the recirculation exhaust gas passage 6, for example, the flow path diameter and the cross-sectional shape is increased. Therefore, the recirculation exhaust gas passage 6 can be easily formed.

  In the above description, a mode in which the half pipe 10 which is a separate member is fitted into the groove 1B is shown, but the half pipe 10 may be integrally formed with the intake manifold 1 by two-color molding or the like.

  An air layer K is provided between the intake manifold 1 and the outer peripheral surface of the half pipe 10 (FIGS. 3 and 4). With this configuration, when the high-temperature EGR gas flows through the recirculation exhaust gas passage 6, the heat transmitted from the half pipe 10 to the intake manifold 1 side can be easily blocked by the air layer K. Therefore, the heat damage which EGR gas exerts on the intake manifold 1 can be suppressed.

A gasket member 20 made of heat resistant resin is connected to the half pipe 10. The gasket member 20 of the present embodiment seals the first gasket member 20a that seals the connecting portion between the groove-shaped space S and the cylinder head 2, and the connecting portion between the suction port 5 of the cylinder head 2 and the intake manifold 1. A second gasket member 20a is provided.
Although the half pipe 10 and the gasket member 20 may be integrally formed, in the present embodiment, both formed separately are assembled (FIG. 5). If both are integrally formed, it is possible to reduce the man-hours for installing the intake manifold.

  The end portion 10 a of the half pipe 10 is formed in a flange shape, and the end portion 10 a is fitted into the gasket member 20 so that both are connected. By sandwiching the gasket member 20 between the intake manifold 1 and the cylinder head 2, airtightness is improved.

  Since the gasket member 20 functions as a sealing material for preventing leakage of EGR gas, the first gasket member 20a can prevent leakage of EGR gas flowing through the groove-shaped space S. In the gasket member 20 b, it is possible to prevent EGR gas from leaking at the connection portion between the cylinder head 2 and the intake manifold 1. Therefore, in this configuration, it is possible to reliably prevent the leaked hot EGR gas from causing heat damage to the intake manifold 1.

The recirculation exhaust gas passage 6 is formed in a flange portion 1 d connected to the cylinder head 2 in the intake manifold 1. As a result, the flow of the recirculated exhaust gas is utilized using the width of the flange portion 1d.

Since the passage 6 can be disposed, the space of the exhaust gas recirculation device X can be saved.

[Another embodiment]
In the embodiment described above, the recirculation exhaust gas passage 6 is a passage surrounded by the groove portion 1 </ b> B and the wall portion 2 b of the cylinder head 2. However, the present invention is not limited to this mode, and the recirculation exhaust gas passage 6 may be configured so that the groove 1B does not face the wall 2b of the cylinder head 2.
For example, the recirculated exhaust gas passage 6 may be formed by forming a tunnel-like pipe portion in the flange portion 1 d of the intake manifold 1. Further, the recirculation exhaust gas passage 6 is disposed adjacent to the three intake passages 1a, 1b, 1c. In this case, for example, a tubular recirculation exhaust gas passage 6 is attached to the intake passages 1a, 1b, and 1c. If it is this structure, it is not necessary to process the groove part 1B which makes the mounting surface 1A of the intake manifold 1 concave.

  INDUSTRIAL APPLICABILITY The present invention can be used in an exhaust gas recirculation device that recirculates exhaust gas to a combustion chamber in an internal combustion engine such as an automobile.

X Exhaust gas recirculation device K Air layer S Groove-like space 1 Intake manifold 1A Mounting surface 2 Cylinder head 2b Wall 3 Flange 4 Exhaust port 5 Intake port 6 Recirculation exhaust gas passage 10 Half pipe 20 Gasket member

Claims (4)

With respect to a resin-made intake manifold attached to the outside of the cylinder head, a groove-like space provided on an attachment surface facing the wall portion of the cylinder head of the intake manifold is provided.
The groove-shaped space has a half pipe embedded in the intake manifold so as to be in close contact with the wall of the cylinder head, while opening to the wall of the cylinder head.
The half pipe is made of a material having heat resistance than the intake manifold, and connects the exhaust port and the intake port of the cylinder head to allow the exhaust gas from the exhaust port to flow into the intake port. An exhaust gas recirculation device for an internal combustion engine as a passage. The exhaust gas recirculation apparatus according to claim 1 , wherein an air layer is provided between the intake manifold and an outer peripheral surface of the half pipe. The exhaust gas recirculation apparatus according to claim 1 or 2 , wherein a gasket member made of a heat-resistant resin that seals a connection portion between the suction port of the cylinder head and the intake manifold is connected to the half pipe. The exhaust gas recirculation apparatus according to any one of claims 1 to 3 , wherein the recirculation exhaust gas passage is formed in a flange portion connected to the cylinder head in the intake manifold.

Images