JP2012062902A - Intake path gas introducing structure and intake manifold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intake path gas introducing structure which can easily discharge condensate and an intake path gas introducing structure and an intake manifold which can uniformly distribute gas between cylinders and uniformly diffuse gas to an intake.SOLUTION: An intake path 4 is formed by connecting an intake branch pipe 6b of the intake manifold 2 to an intake port 22 at connecting end faces 20. An exhaust gas introducing path 12 is introduced to the intake branch pipe 6b. An end of the exhaust gas introducing path 12 opened to the intake path 4 is formed to protrude to the intake path 4. An end face 12c of the exhaust gas introducing path 12 has a central side of the intake path of the end face 12c inclined to a direction more reverse to a direction of an intake flow than the connecting end face 20 and inclined to a direction more reverse to the direction of the intake flow than a position orthogonal to an axis of the exhaust gas introducing path 12 itself.

Description

  The present invention relates to an intake path gas introduction structure for introducing gas from a gas introduction path to an intake flow in an intake path of an internal combustion engine, and an intake manifold to which the intake path gas introduction structure is applied.

  In the exhaust gas recirculation device, exhaust gas is mixed with intake air by supplying the exhaust gas to a surge tank or an intake branch pipe (see, for example, Patent Documents 1 to 3). In Patent Document 1, exhaust gas is uniformly distributed to each cylinder by introducing exhaust gas into the intake air from two openings, a circular shape and an oval shape, which open to the surge tank. In Patent Document 2, the exhaust gas recirculation passage led upstream from the swirl control valve is formed into an arc-like oval shape to raise the temperature of the intake port and promote the vaporization of fuel. In Patent Document 3, an oblong exhaust inlet that is long in the flow direction is formed immediately below the throttle valve to achieve uniform mixing of intake and exhaust and prevention of deposit adhesion.

Japanese Patent Laid-Open No. 7-259656 (page 3, FIGS. 2 and 3) Japanese Patent Application Laid-Open No. 7-247917 (page 3, FIG. 5) JP-A-11-210560 (5th page, FIG. 11)

  In some cases, water vapor contained in the exhaust gas is cooled during the exhaust gas circulation to generate condensed water. When this condensed water accumulates in the exhaust introduction path into the intake air, the exhaust introduction path is blocked and the flow of the introduced exhaust is biased or intermittently introduced, resulting in uniform exhaust diffusion into the intake air. Uniform exhaust distribution among the cylinders becomes difficult, and exhaust recirculation cannot be performed smoothly. For this reason, it is necessary to allow the condensed water to flow out from the exhaust introduction path smoothly along the exhaust introduction path wall so as not to accumulate in the exhaust introduction path.

Patent Documents 1 to 3 do not consider the condensed water generated until the exhaust gas is introduced into the intake air, and are insufficient for countermeasures against problems caused by introducing the exhaust gas by condensed water.
Further, in order to diffuse the exhaust gas uniformly during the intake air without being biased between the cylinders from the exhaust introduction passage, it is not a configuration that opens at the intake passage wall surface near the throttle valve as in Patent Documents 1 to 3, It is conceivable that the intake air is opened to a position protruding into the intake air flow to some extent in the intake air flow after branching for each cylinder. However, if the opening is made in this way, it is likely to be affected by the intake pulsation, and on the contrary, the uniform diffusion of the exhaust gas into the intake air is hindered and the uniform exhaust gas distribution for each cylinder may be difficult.

The same is true for other gases such as blow-by gas and fuel vapor from canisters.
The present invention makes it possible to smoothly discharge a condensed liquid and thereby to smoothly introduce a gas into the intake air, and to achieve a uniform gas distribution structure between the cylinders and a uniform diffusion of the gas into the intake air. Therefore, an object of the present invention is to provide an intake path gas introduction structure capable of smoothly introducing gas into the intake air and an intake manifold for this structure.

In the following, means for achieving the above object and its effects are described.
An intake path gas introduction structure according to claim 1 is an intake path gas introduction structure that introduces gas from a gas introduction path to an intake flow in an intake path of an internal combustion engine, and the intake path is an intake manifold intake manifold. A gas inlet is formed by connecting a branch pipe and an intake port formed in a cylinder head of an internal combustion engine at connection end faces, and a gas introduction path is introduced into the intake branch pipe and opens into the intake path The front end of the path is formed so as to protrude into the intake path, and the front end surface of the gas introduction path inclines the center of the intake path of the front end surface in a direction opposite to the intake flow direction from the connection end surface. In addition, it is characterized in that it is formed so as to be inclined in the direction opposite to the intake flow direction with respect to the axial orthogonal state position in the gas introduction path itself.

  The gas introduction path is open in a state where the tip projects into the intake path by the intake branch pipe. Accordingly, it is possible to easily form a gas introduction path that uniformly distributes and diffuses the gas during intake to each cylinder.

  Further, the front end surface of the gas introduction path is inclined in the direction of the intake path center of the front end surface in a direction opposite to the intake flow direction with respect to the connection end surface between the intake branch pipe and the intake port. Can be difficult. Therefore, the pumping loss of the internal combustion engine can be suppressed.

  Furthermore, in the case of an internal combustion engine that blows back from the combustion chamber side to the intake path side, such as an Atkinson cycle engine, the exposure to the blowback is made by tilting the center side of the intake path on the tip surface in the direction opposite to the intake flow direction. This is weakened, or it is difficult to guide the blowback back into the gas introduction path, thereby producing a deposit adhesion preventing effect.

  In addition, the front end surface of the gas introduction path is not set to the position perpendicular to the axis in the gas introduction path as described above, but the center of the intake path is inclined in the direction opposite to the intake flow direction. Thus, the gas can be uniformly distributed and diffused during the intake air to each cylinder, and the resistance to the intake air flow can be further reduced.

Further, since the center of the intake path can be greatly tilted in the direction opposite to the intake flow direction, the deposit adhesion preventing effect against the above-described blowback can be enhanced.
The intake path gas introduction structure according to claim 2 is characterized in that, in claim 1, the gas introduction path is formed in a direction intersecting at an acute angle with respect to the intake flow direction in the intake path.

With such an acute angle, the resistance of the intake air flow can be reduced even if the tip of the gas introduction passage protrudes into the intake passage.
According to a third aspect of the present invention, there is provided the intake path gas introduction structure according to the first or second aspect, wherein the gas introduction path is arranged in an inclined state in which the gas flow direction is downward.

  By tilting the gas introduction path in this way, even if water or the like condenses in the gas introduction path, it accelerates the flow of the condensed liquid in the gas flow direction and discharges condensed water or the like into the intake air. Well done.

  In the intake path gas introduction structure according to claim 4, in any one of claims 1 to 3, the tip surface of the gas introduction path is in a direction opposite to the intake flow direction than the position orthogonal to the axis of the intake path. It is formed by inclining the central side of the intake path.

  In this way, the front end surface of the gas introduction path is configured so that the intake path center side is inclined in the direction opposite to the intake flow direction from the orthogonal state position with respect to the intake path axis. The gas can be uniformly distributed and diffused in the inside, and the resistance to the intake flow can be made difficult.

Furthermore, the deposit adhesion prevention effect with respect to the above-mentioned blow-back is produced.
In the intake path gas introduction structure according to claim 5, gas is supplied by being connected to a metal gas supply pipe at a resin connection portion in any one of claims 1 to 4. In addition, the connecting portion is formed to have a larger diameter than the gas supply pipe.

  Because the connecting part has a diameter larger than that of the gas supply pipe, even if a high-temperature gas is supplied from the gas supply pipe, the resin-made connecting part is not directly hit, and strength reduction at the connecting part is prevented. Can do.

The intake path gas introduction structure according to a sixth aspect is characterized in that, in the fifth aspect, an inner peripheral edge portion of the connection portion is chamfered at a contact portion with the gas supply pipe.
Further, in the connection portion, the inner peripheral edge portion is chamfered at the contact portion with the gas supply pipe. As a result, even if the connection with the gas supply pipe is slightly shifted in the direction perpendicular to the axis, it is possible to prevent the hot gas from directly hitting the leading edge of the connecting portion, and to reliably prevent a decrease in strength at the connecting portion. it can.

  The intake path gas introduction structure according to claim 7, wherein the gas is a fuel derived from exhaust of an internal combustion engine, blow-by gas of the internal combustion engine, and fuel evaporation from a fuel tank. Any one or more of steam is characterized.

  Examples of the gas introduced into the intake air flow from the gas introduction path include exhaust of the internal combustion engine, blow-by gas, and fuel vapor, and such gas can be smoothly introduced into the intake air.

The intake manifold according to an eighth aspect is characterized in that the configuration according to any one of the first to seventh aspects is applied.
By using such an intake manifold, the effects as described above can be produced.

FIG. 2 is a main part configuration diagram showing a front surface and a back surface of the intake manifold according to the first embodiment. The principal part block diagram which shows the left side surface and right side surface of the said intake manifold. The principal part perspective view of the said intake manifold. XX sectional drawing in FIG. The longitudinal cross-sectional view of the exhaust introduction path in the said intake manifold. FIG. 6 is a longitudinal sectional view of an exhaust introduction path in an intake manifold according to a second embodiment. Sectional drawing equivalent to the said FIG. 4 in Embodiment 2. FIG. Sectional drawing which shows the inclination position of the front end surface in the exhaust_gas | exhaustion introduction path of Embodiment 2. FIG. Sectional drawing which shows the inclination position of the front end surface in the exhaust_gas | exhaustion introduction path of Embodiment 2. FIG. Sectional drawing which shows a connection state with the exhaust gas supply pipe | tube in the exhaust gas supply part of Embodiment 3. FIG.

[Embodiment 1]
1 to 3 show a configuration of main parts of an intake manifold 2 to which the above-described invention is applied in an internal combustion engine. 1A is a front view, FIG. 2B is a rear view, FIG. 2A is a left side view, FIG. 1B is a right side view, and FIG. 3 is a perspective view. FIG. 4 is a sectional view taken along line XX in FIG.

  The intake manifold 2 includes a common intake path 4 that functions as a surge tank, and intake air is introduced from the throttle valve through the common intake path 4. An intake branch pipe assembly 6 is provided downstream of the common intake path 4. The common intake passage 4 and the intake branch pipe assembly 6 are integrally formed of resin. In the drawing, in order to make the overall shape of the intake manifold 2 easy to understand, a rib or the like is not provided, but various ribs for reinforcement, through holes for installing an intake air temperature sensor, etc., the intake manifold 2 Various engaging portions for supporting the device can be provided on the outer peripheral surface.

  Here, the internal combustion engine has four cylinders, and the intake branch pipe assembly 6 includes four intake branch pipes 6a, 6b, 6c, and 6d. The internal combustion engine may have another number of cylinders. In this case, the intake manifold 2 is provided with intake branch pipes corresponding to the corresponding number of cylinders. In the case of a multi-bank internal combustion engine such as a V-type engine, an intake manifold 2 is provided for each bank, and each intake manifold 2 is provided with intake branch pipes corresponding to the number of cylinders in the same bank. Become.

  As shown in FIG. 4, the lower side of the intake branch pipe assembly portion 6 is covered by joining a resin cover 8a by welding, fitting, or the like. A chamber (corresponding to a common gas chamber) 8 is formed. Exhaust gas is supplied to the EGR chamber 8 from an exhaust gas supply unit 8b formed on one side of the intake branch pipe assembly 6 when exhaust gas recirculation is executed via an EGR valve provided in the EGR device. From the EGR chamber 8, exhaust introduction paths (corresponding to gas introduction paths) 10, 12, 14, and 16 for the intake branch pipes 6a to 6d extend linearly, respectively.

  FIG. 5A shows a vertical cross-sectional view in the direction perpendicular to the axis of these exhaust introduction passages 10-16. The inner peripheral surfaces of the exhaust introduction paths 10 to 16 are composed of bottom surfaces 10a, 12a, 14a and 16a and curved wall surfaces 10b, 12b, 14b and 16b. The bottom surfaces 10a, 12a, 14a, and 16a have a shape that appears as a substantially horizontal straight line on the lower side in the cross section perpendicular to the axis. The curved wall surfaces 10b, 12b, 14b, and 16b are convex shapes that connect the both ends of the straight line (the bottom surfaces 10a, 12a, 14a, and 16a) with an angle (substantially orthogonal here) on the upper side in the cross section orthogonal to the axis. It has a shape that appears as a curved line.

  Due to the arrangement of the intake manifold 2 with respect to the internal combustion engine, the exhaust introduction passages 10 to 16 are inclined with the flow direction of the exhaust being downward. As a result, the planar bottom surfaces 10a to 16a are also inclined downward toward the intake branch pipes 6a to 6d. Further, the cover 8a constituting the EGR chamber 8 by covering the intake branch pipe collecting portion 6 from the lower side serves as a bottom plate. The flat upper surface of the cover 8a, that is, the bottom surface of the EGR chamber 8 is used. 8c is a surface that is continuous with the bottom surfaces 10a to 16a of the exhaust introduction paths 10 to 16 on the same plane. Therefore, the bottom surface 8c of the EGR chamber 8 is also inclined downward toward the intake branch pipes 6a to 6d.

  The distal end surfaces 10c, 12c, 14c, and 16c of the exhaust introduction paths 10 to 16 are not flush with the inner peripheral surface 18 of the intake branch pipes 6a to 6d, and the curved wall surfaces 10b to 16b side (the intake path center side) is the intake branch pipe 6a. Projects into the intake path in -6d. However, the curved wall surfaces 10b to 16b are inclined from the connection end surface 20 of the intake branch pipes 6a to 6d in a direction opposite to the intake flow direction (inclined from the connection end surface 20 by an angle θ1).

In the present embodiment, the connection end faces 20 of the intake branch pipes 6a to 6d are inclined upward in the intake flow direction from the intake flow orthogonal state position (same as the axial branch orthogonal position of the intake branch pipe) ( For example, θ0
= Around 10 °). The distal end surfaces 10c to 16c of the exhaust introduction paths 10 to 16 are in a state where the curved wall surfaces 10b to 16b are inclined in the direction opposite to the intake flow direction from the intake flow orthogonal state position. Here, the front end surfaces 10c to 16c are in a state where the curved wall surfaces 10b to 16b are inclined in the direction opposite to the intake air flow direction with respect to the axial orthogonal state position in the exhaust introduction passages 10 to 16 themselves (here, θ2 = 45 to 55). ° CA).

  When this intake manifold 2 is attached to an intake port 22 formed on a metal cylinder head of an internal combustion engine and the EGR device actually functions, exhaust is exhausted into the EGR chamber 8 from the exhaust supply section 8b as shown by the arrow in the figure. be introduced. Then, the air is diverted to the exhaust introduction paths 10 to 16 and distributed to the intake branch pipes 6a to 6d. As a result, the exhaust gas is introduced into the intake air in the intake passage for each cylinder, mixed with the intake air, and supplied to each cylinder.

According to the first embodiment described above, the following effects can be obtained.
(I). The bottom surfaces 10a to 16a of the exhaust introduction paths 10 to 16 are connected to the curved wall surfaces 10b to 16b with an angle on both sides thereof. Here, the bottom surfaces 10a to 16a and the curved wall surfaces 10b to 16b are connected substantially orthogonally. As a result, each of the exhaust introduction paths 10 to 16 is formed with a corner C along the exhaust flow direction as shown in FIG. When the water vapor contained in the exhaust gas flowing through each exhaust introduction path 10-16 condenses in each exhaust introduction path 10-16, condensation is likely to occur particularly in such a corner C. Easy to get together.

  Therefore, as shown in FIG. 5B, the condensed water W generated in each of the exhaust introduction paths 10 to 16 is first generated at the corner C or concentrated at the corner C. Then, the condensed water flows through the corners C and flows through the exhaust introduction paths 10 to 16.

  When a large amount of condensed water is generated more rapidly than the amount of condensed water transferred at the corner C, the condensed water flows out to the bottom surfaces 10a to 16a adjacent to the corner C as shown in FIG. Collects in ~ 16a and produces high fluidity. For this reason, it is easily moved and discharged from the exhaust introduction paths 10 to 16 by friction with the exhaust flow flowing through the exhaust introduction paths 10 to 16 or by the inclination of the exhaust introduction paths 10 to 16.

  In this way, the condensed water can be smoothly discharged through the corners C and the bottom surfaces 10a to 16a of the exhaust introduction paths 10 to 16 so that the condensed water does not accumulate in the exhaust introduction paths 10 to 16, and the condensed water is discharged into the exhaust introduction path. 10 to 16 does not accumulate and does not hinder uniform exhaust diffusion into the intake air and uniform exhaust distribution among the cylinders. In this way, smooth exhaust introduction by the EGR device becomes possible.

  (B). Here, in particular, each of the exhaust introduction passages 10 to 16 is formed in a straight line and is arranged in an inclined state in which the flow direction of the exhaust is downward, thereby further promoting the flow of condensed water in the exhaust flow direction, The discharge of condensed water during intake can be made more effective.

  In addition, the bottom surfaces 10 a to 16 a of the exhaust introduction paths 10 to 16 are made continuous on the same plane as the bottom surface 8 c of the EGR chamber 8. Thus, condensed water can be smoothly discharged to the intake branch pipes 6a to 6d without accumulating condensed water between the EGR chamber 8 and the exhaust introduction paths 10 to 16.

  (C). Each exhaust introduction path 10-16 is introduced from the lower side with respect to each intake branch pipe 6a-6d, and the tip of each exhaust introduction path 10-16 opened to each intake branch pipe 6a-6d has curved wall surfaces 10b-16b. The sides protrude into the intake branch pipes 6a to 6d and open. As a result, the exhaust can be uniformly diffused with respect to the intake air, and the curved wall surfaces 10b to 16b protrude into the intake branch pipes 6a to 6d. Even if the tip of the valve is exposed during the intake air flow, the portion where no corner is formed protrudes during the intake air flow, so that the resistance to the intake air flow is less likely to occur. Therefore, the pumping loss of the internal combustion engine can be suppressed.

  In particular, the distal end surfaces 10c to 16c of the exhaust introduction paths 10 to 16 are formed in a state in which the curved wall surfaces 10b to 16b are inclined in the direction opposite to the intake flow direction from the connection end surface 20 of each intake branch pipe 6a to 6d. ing. Actually, the curved wall surfaces 10b to 16b are inclined in the direction opposite to the intake flow direction from the orthogonal state position with respect to the axes of the intake branch pipes 6a to 6d. It is also a state (45 to 55 °) in which the curved wall surfaces 10b to 16b are inclined in the direction opposite to the intake flow direction from the state position. Therefore, this makes it possible to evenly distribute and diffuse the exhaust during intake to each cylinder, and to make resistance to intake flow more difficult.

  (D). Here, when an Atkinson cycle engine is used as an internal combustion engine to which the intake manifold 2 is applied, the intake air once sucked from the combustion chamber side is blown back to the intake path side. Therefore, the deposit in the combustion chamber rides back and collides with the front end surfaces 10c to 16c of the exhaust introduction passages 10 to 16, and deposits are likely to occur.

  However, in the present embodiment, the tip surfaces 10c to 16c of the exhaust introduction passages 10 to 16 are exposed to the tip surfaces 10c to 16c by blowing back by the amount of inclination of the curved wall surfaces 10b to 16b in the direction opposite to the intake flow direction. This is weakened or it is difficult to guide the blowback into the exhaust introduction paths 10 to 16. Therefore, deposit adhesion is sufficiently prevented.

[Embodiment 2]
FIG. 6 shows a longitudinal section in the direction perpendicular to the axis of the exhaust introduction path in the present embodiment. Other configurations are the same as those of the first embodiment.

  The inner peripheral surface of the exhaust introduction path 110 shown in FIG. 6A does not have the relationship between the curved wall surface and the bottom surface as in the first embodiment, and the ceiling surface 110a, the side surfaces 110b and 110c, and the bottom surface 110d The cross-sectional rectangle which consists of consists of. The ceiling surface 110a may be a trapezoid whose width is narrower than the bottom surface 110d, and conversely, the bottom surface 110d may be a trapezoid whose width is narrower than the ceiling surface 110a. Further, the heights of the side surfaces 110b and 110c need not be the same.

The inner peripheral surface of the exhaust introduction passage 120 shown in FIG. 6B is substantially rectangular in cross section, but the corner 120a is provided with a corner radius. The rest is the same as FIG. 6A.
An inner peripheral surface 130a of the exhaust introduction passage 130 shown in FIG. 6C has a circular cross section. In addition, (
It may be a horizontally long elliptical inner peripheral surface 140a as in the exhaust introduction path 140 shown in D) or a vertically long elliptical shape.

In the present embodiment, any one of the above-described exhaust introduction paths 110, 120, 130, and 140 and modifications thereof is applied to the exhaust introduction path.
As shown in FIG. 7, the front end surface 111 a of the exhaust introduction passages 110 to 140 having such a shape intakes the intake path center side P more than the position of the connection end surface 112 a of the intake branch pipe 112 connected to the metal intake port 122. The state is inclined in the direction opposite to the flow direction. In the example of FIG. 7, the front end surface 111a is inclined from the position of the connection end surface 112a in the direction opposite to the intake flow direction so as to be between the intake flow orthogonal state position and the connection end surface 112a position. This inclination indicates a relative relationship with the connection end surface 112a. Actually, the tip end surface 111a is close to the intake flow orthogonal state position, so that it is raised more than the connection end surface 112a when viewed from the intake flow direction. It will be.

  In addition to the inclined position of the front end surface 111a illustrated in FIG. 7, the position may be substantially the same (including the same position) as the intake flow orthogonal state position as shown in FIG. Further, by tilting in the direction opposite to the intake flow direction, the tip surface 111a may be located between the intake flow orthogonal state position and the axial orthogonal state position of the exhaust introduction passages 110 to 140 as shown in FIG.

  Further, by tilting in the direction opposite to the intake flow direction, the front end surface 111a may be set substantially at the same position as the axial orthogonal state position of the exhaust introduction paths 110 to 140 as shown in FIG. Further, by inclining in the direction opposite to the intake air flow direction, as shown in FIG. 9B, the front end surface 111a and the front end position shown in FIG. 4 of the first embodiment shown in FIG. It may be between the position of the surface (12c). Further, the position of the front end surface (12c) shown in FIG. 4 of the first embodiment may be made to be inclined in the direction opposite to the intake flow direction.

According to the second embodiment described above, the following effects can be obtained.
(I). When the intake branch pipe 112 is integrally formed by resin injection molding, the exhaust introduction path is generally linear from the top of the mold release, and the tip end face is generally formed at the same position as the connection end face 112a. . However, in this case, the front end surface of the exhaust introduction path rises greatly in the intake branch pipe 112 and the flow resistance of the intake air flow increases. In addition, when an Atkinson cycle engine is used, deposit adhesion tends to increase due to the above-described blow-back.

  However, as shown in FIG. 7 of the present embodiment, the tip end surface 111a is formed so as to be inclined in the direction opposite to the intake air flow, so that the tip end surface 111a of the exhaust introduction passages 110 to 140 in the intake branch pipe 112 is formed. The rise of becomes smaller. As shown in FIGS. 8 and 9, if the degree of inclination in the opposite direction to the intake air flow is further increased, the rising of the tip surface 111a in the intake branch pipe 112 is reduced accordingly. As a result, the exhaust gas can be uniformly distributed and diffused during the intake air to each cylinder, and the resistance to the intake air flow can be further reduced. Further, even if blowback occurs, deposit adhesion can be suppressed.

  In addition, the tip surface 111a is not completely parallel to the intake air flow, but protrudes into the intake branch pipe 112 as much as possible, thereby suppressing the deviation of the exhaust gas supply into the intake air and mixing with the intake air. It can be made uniform.

  (B). Since the exhaust introduction passages 110 to 140 are formed in a straight line and arranged in an inclined state with the flow direction of the exhaust gas downward, the flow of condensed water in the exhaust flow direction is promoted, and the flow into the intake air is promoted. It is possible to improve the discharge of condensed water.

  In addition, as shown in FIG. 7, the bottom surfaces 111 c of the exhaust introduction paths 110 and 120 are continuous on the same plane as the bottom surface 124 a of the EGR chamber 124. Thus, condensed water can be smoothly discharged to the intake branch pipe 112 side without accumulating condensed water between the EGR chamber 124 and the exhaust introduction paths 110 and 120.

  Further, the lowermost portions of the inner peripheral surfaces 130 a and 140 a of the exhaust introduction paths 130 and 140 are also made continuous on the same plane as the bottom surface 124 a of the EGR chamber 124. As a result, the exhaust introduction paths 130 and 140 can be smoothly discharged to the intake branch pipe 112 side without accumulating condensed water.

[Embodiment 3]
In the present embodiment, a structural example of a connection portion between the exhaust supply part 8b (corresponding to the connection part) and the exhaust supply pipe (corresponding to the gas supply pipe) shown in FIGS. Other configurations are the same as those of the first embodiment or the second embodiment.

  As shown in FIG. 10, the intake manifold incorporated in the internal combustion engine is connected to the flange portion 200a of the exhaust supply pipe 200 of the EGR device by bolting at the flange portion 8d of the exhaust supply portion 8b.

However, the inner diameter D1 of the exhaust supply pipe 200 is smaller than the inner diameter D2 on the exhaust supply section 8b side. Further, the inner peripheral edge portion 8e of the flange portion 8d is chamfered.
According to the third embodiment described above, the following effects can be obtained.

  (I). Since the inner diameter D2 of the exhaust supply part 8b is larger than the inner diameter D1 of the exhaust supply pipe 200, even if high-temperature exhaust gas that is not sufficiently cooled is supplied from the exhaust supply pipe 200, the resin exhaust supply part There is no direct hit on 8b. Thus, since it is not directly exposed to high temperature exhaust, the strength reduction in the exhaust supply part 8b can be prevented.

  (B). In the exhaust supply part 8b, the inner peripheral edge part 8e is chamfered at the contact part of the flange part 8d connected to the exhaust supply pipe 200 side. As a result, even if the connection position with the flange portion 200a of the exhaust supply pipe 200 is slightly shifted in the direction perpendicular to the axis, it is possible to prevent high-temperature exhaust from directly hitting the front edge of the exhaust supply portion 8b. It is possible to reliably prevent the strength of the portion 8b from decreasing particularly at the flange portion 8d.

(C). Other effects are as described in the first embodiment or the second embodiment.
[Other embodiments]
(A). In each of the above embodiments, the gas introduction path introduces exhaust gas into the intake air. However, in addition to the exhaust gas, the fuel vapor derived from the blow-by gas of the internal combustion engine or the fuel evaporation from the fuel tank (from the canister, etc.) (Purge gas) may be introduced into the intake air. Alternatively, any combination of exhaust gas, blow-by gas, and fuel vapor may be introduced into the intake air. Even with such a gas, even if condensed water or other condensed liquid is generated, it can be discharged smoothly, and further, the gas can be evenly distributed and uniformly diffused during intake to each cylinder. In addition, it is possible to make the gas introduction path difficult to become the resistance of the intake flow. Therefore, it is possible to smoothly introduce the gas into the intake air.

  (B). The inclined state (FIGS. 7 to 9) of the distal end surface 111a of the second embodiment can be applied to the inclined state of the distal end surface 12c (FIG. 4) of the first embodiment, and will be described in the second embodiment. It is possible to produce the effect as it is.

  (C). In the second embodiment, the exhaust introduction paths 110 to 140 are introduced into the intake branch pipe 112 from the lower side of the intake branch pipe 112. However, if there is a space for forming the exhaust introduction paths 110 to 140, each intake branch pipe is provided. It may be from above 112 or from the side. As described above, the effect described in the second embodiment can be produced by inclining the intake path central side P in the direction opposite to the intake flow direction.

  2 ... intake manifold, 4 ... common intake path, 6 ... intake branch pipe assembly, 6a, 6b, 6c, 6d ... intake branch pipe, 8 ... EGR chamber, 8a ... cover, 8b ... exhaust supply part, 8c ... bottom face, 8d ... flange portion, 8e ... inner peripheral edge portion, 10, 12, 14, 16 ... exhaust introduction path, 10a, 12a, 14a, 16a ... bottom surface, 10b, 12b, 14b, 16b ... curved wall surface, 10c, 12c, 14c, 16c ... tip surface, 18 ... inner peripheral surface, 20 ... connection end surface, 22 ... intake port, 110, 120, 130, 140 ... exhaust introduction path, 110a ... ceiling surface, 110b, 110c ... side surface, 110d ... bottom surface, 111a ... Front end surface, 111c ... bottom surface, 112 ... intake branch pipe, 112a ... connection end surface, 120 ... exhaust introduction path, 120a ... corner, 122 ... intake port, 124 ... EGR chamber, 124a ... bottom , 130 ... exhaust introduction path, 130a ... inner peripheral surface, 140 ... exhaust introduction path, 140a ... inner peripheral surface, 200 ... exhaust supply pipe, 200a ... flange portion, C ... corner, P ... central side of intake path, W ... condensation water.

Claims (8)

An intake path gas introduction structure for introducing gas from a gas introduction path to an intake flow in an intake path of an internal combustion engine,
The intake path is formed by connecting the intake branch pipe of the intake manifold and the intake port formed in the cylinder head of the internal combustion engine at the connection end faces, and the gas introduction path is introduced to the intake branch pipe. The front end of the gas introduction path that opens to the intake path is formed to protrude into the intake path, and the front end surface of the gas introduction path is located on the center side of the intake path of the front end surface with respect to the connection end surface. And an intake passage gas introduction structure characterized in that the intake passage gas is inclined in the opposite direction to the intake flow direction with respect to the axial orthogonal state position in the gas introduction passage itself. 2. The intake passage gas introduction structure according to claim 1, wherein the gas introduction passage is formed in a direction intersecting at an acute angle with respect to the intake flow direction in the intake passage. The intake path gas introduction structure according to claim 1 or 2, wherein the gas introduction path is arranged in an inclined state with a gas flow direction downward. The front end surface of the gas introduction path according to any one of claims 1 to 3 is formed by inclining the intake path center side in a direction opposite to the intake flow direction with respect to a position orthogonal to the intake path axis. An intake path gas introduction structure characterized by that. The gas supply pipe according to any one of claims 1 to 4, wherein gas is supplied by being connected to a metal gas supply pipe at a resin connection section, and the connection section is larger than the gas supply pipe. An intake passage gas introduction structure characterized by being formed in a diameter. 6. The intake path gas introduction structure according to claim 5, wherein an inner peripheral edge portion of the connection portion is chamfered at a contact portion with the gas supply pipe. 7. The gas according to claim 1, wherein the gas is any one or more of exhaust gas from an internal combustion engine, blow-by gas from the internal combustion engine, and fuel vapor derived from fuel evaporation from a fuel tank. Intake path gas introduction structure. An intake manifold, to which the configuration according to any one of claims 1 to 7 is applied.