JP7146523B2 - Intake manifold - Google Patents

Description

The present invention relates to an intake manifold for an internal combustion engine.

An internal combustion engine is provided with an intake manifold that forms part of an intake system (see Patent Document 1). The intake manifold includes a surge tank, a cylindrical introduction portion provided on the top wall of the surge tank, and a plurality of branch pipes connected to a wall portion (bottom wall) of the surge tank facing the introduction portion. and The introduction portion communicates with an intake passage on the upstream side in the intake flow direction, and the plurality of branch pipes are connected to respective ports of the internal combustion engine. The intake manifold distributes the air taken into the intake passage to each cylinder of the internal combustion engine.

Further, it has been proposed to connect one end of a passage (EGR passage) for recirculating part of the exhaust gas in the exhaust passage of the internal combustion engine to the intake passage to the surge tank of the intake manifold. In such an intake manifold, exhaust gas (so-called EGR gas) introduced into the surge tank through the EGR passage is mixed with intake air in the surge tank and then distributed to each cylinder of the internal combustion engine.

JP-A-2005-9488

In the intake manifold, there is a possibility that the air once introduced into the surge tank flows back into the intake passage on the upstream side via the introduction portion, that is, a so-called blow-back phenomenon may occur. In an intake manifold with a structure in which the EGR passage communicates with the surge tank, when blow-back phenomenon occurs, EGR gas is introduced back into the intake passage on the upstream side together with the intake air, albeit temporarily. . EGR gas contains particulate matter (eg, soot). Therefore, the blow-back phenomenon causes deposits in the intake passage on the upstream side.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an intake manifold capable of suppressing the formation of deposits due to blow-back phenomenon.

An intake manifold for solving the above problems includes a surge tank having a top wall, a bottom wall, and an annular side peripheral wall erected from peripheral edges of the top wall and the bottom wall, and one end communicating with the top wall. a cylindrical introduction portion that introduces air into the surge tank by means of a portion; a plurality of branch pipes that are individually communicated with the bottom wall to distribute the air in the surge tank; and one end of which communicates with the side peripheral wall and a cylindrical EGR portion that introduces EGR gas into the surge tank in a manner in which the EGR gas is introduced into the surge tank along the direction in which the openings of the branch pipes are arranged, and along the periphery of the opening of the introduction portion. a baffle plate protruding from the inner wall of the surge tank in a manner extending in the direction of the surge tank, and the baffle plate is located inside the surge tank when the surge tank is viewed in the direction in which the introduction portion extends. When an EGR virtual line connecting the center of the opening of the EGR section and the center of the opening of the EGR section is drawn, it is not provided in the non-arranged portion including the portion overlapping with the EGR virtual line. It is provided in the part other than the part.

The blowback phenomenon occurs as follows. That is, a part of the air introduced into the surge tank from the introduction part of the top wall of the surge tank hits the inner wall surface of the surge tank, flows along the inner wall surface, and flows around the opening peripheral edge of the introduction part. It will return to the vicinity. The air that has thus returned to the vicinity of the periphery of the opening of the introduction section enters the introduction section while being caught in the flow of air that flows into the surge tank from the introduction section from the periphery, and returns to the intake passage on the upstream side. .

According to the above configuration, since the baffle plate is provided at the periphery of the opening of the introduction portion in the surge tank, the flow of air returning to the vicinity of the periphery of the opening of the introduction portion collides with the baffle plate and escapes from the inner wall surface of the surge tank. It can be bent in the direction of separation, that is, in the direction along the flow of air flowing into the surge tank from the introduction portion. Thus, according to the above configuration, it is possible to provide a structure in which the flow of air returned to the vicinity of the periphery of the opening of the introduction section is less likely to flow toward the inside of the introduction section. As a result, it is possible to suppress the occurrence of the blow-back phenomenon, and thus it is possible to suppress the occurrence of deposits due to the occurrence of the blow-back phenomenon.

In the above configuration, the EGR gas flows into the surge tank along the direction in which the openings of the branch pipes are arranged in the surge tank through the EGR portion that communicates with the side peripheral wall of the surge tank. . Therefore, it can be said that the distribution amount of EGR gas to each branch pipe and thus to each cylinder of the internal combustion engine tends to vary, such that EGR gas flows into the branch pipe closer to the EGR portion more easily.

In this respect, according to the above configuration, the air can flow out toward the opening of the EGR portion from the non-arranged portion of the opening peripheral edge of the introduction portion where the baffle plate is not provided. It can collide with the flow of EGR gas flowing into the surge tank from the section. As a result, the air and the EGR gas can be easily mixed in the surge tank, so that variations in the distribution amount of the EGR gas to each cylinder of the internal combustion engine can be suppressed.

According to the present invention, it is possible to suppress the occurrence of deposits due to the blowback phenomenon.

A perspective view of one embodiment of an intake manifold. FIG. 2 is a perspective view of the intake manifold as viewed in the direction of arrow 2 in FIG. 1; FIG. 2 is an exploded perspective view of the intake manifold; The perspective view which looked at the 1st member from diagonally downward. FIG. 2 is a cross-sectional view along line 5-5 of FIG. 1 of the intake manifold; The top view of a 2nd member. FIG. 6 is a cross-sectional view of the intake manifold taken along line 7-7 in FIG. 5; The bottom view of a 1st member. Fig. 3 is a side cross-sectional view showing an enlarged surge tank and its surroundings; FIG. 4 is an enlarged cross-sectional view showing a concave groove and its surroundings in the surge tank;

An embodiment of an intake manifold will be described below with reference to FIGS. 1 to 10. FIG. In this embodiment, the up-down direction in FIG. 1 will be described as the up-down direction of the intake manifold 10 .

As shown in FIGS. 1 to 3, the intake manifold 10 is composed of four vertically divided members (first member 11, second member 12, third member 13, and fourth member 14). ing. These first member 11, second member 12, third member 13, and fourth member 14 are all made of a hard synthetic resin material. In the intake manifold 10, the first member 11, the second member 12, the third member 13, and the fourth member 14 are stacked (state shown in FIG. 1), and the members 11 to 14 are fixed to each other by vibration welding. It has a structured structure.

The intake manifold 10 has a surge tank 21 , an introduction portion 22 , a plurality of (three in this embodiment) branch pipes 23 , and a mounting flange 24 .
The surge tank 21 includes a top wall 21A constituting an upper wall portion, an annular side peripheral wall 21B extending downward from the peripheral edge of the top wall 21A, and a lower side peripheral wall 21B blocking the lower portion of the side peripheral wall 21B. and a bottom wall 21C forming a wall portion. The surge tank 21 functions as a volume that temporarily stores air.

The introduction portion 22 is provided on the top wall 21A of the surge tank 21 so as to protrude outward in a cylindrical shape. The inner wall of the introduction portion 22 has a cylindrical shape extending in the vertical direction. One end of the introduction portion 22 is open inside the surge tank 21 (specifically, the inner surface of the top wall 21A), and the other end is a portion of the intake passage of the internal combustion engine on the upstream side in the intake flow direction (specifically, the throttle). mechanism) is fixed.

A plurality of branch pipes 23 curve and extend to connect the bottom wall 21</b>C of the surge tank 21 and the mounting flange 24 . One end of each branch pipe 23 is open inside the surge tank 21 (specifically, the inner surface of the bottom wall 21C), and the other end is open at the connecting surface 24A of the mounting flange 24. As shown in FIG.

The mounting flange 24 has a plate-like shape extending in the direction in which the ends of the branch pipes 23 are arranged (horizontal direction in FIG. 1). By fixing the mounting flange 24 to the outer wall of the internal combustion engine (not shown), each branch pipe 23 of the intake manifold 10 is connected to each intake port of the internal combustion engine.

In the intake manifold 10 , the air adjusted through the operation of the throttle mechanism is introduced into the surge tank 21 through the introduction portion 22 . The air introduced into the surge tank 21 is distributed and supplied to each intake port of the internal combustion engine via each branch pipe 23 .

As shown in FIGS. 4 and 5, the side peripheral wall 21B of the intake manifold 10 is provided with an EGR portion 26 that extends so as to communicate between the inside and outside of the surge tank 21 . The EGR portion 26 forms part of an EGR passage for introducing EGR gas into the surge tank 21 . The EGR portion 26 extends through the side peripheral wall 21B of the surge tank 21 and the mounting flange 24 . The inner wall of the EGR portion 26 is substantially cylindrical. One end of the EGR portion 26 is open inside the surge tank 21 , and the other end is open at the connecting surface 24</b>A of the mounting flange 24 . In the intake manifold 10 , by fixing the mounting flange 24 to the outer wall of the internal combustion engine, it becomes possible to introduce part of the exhaust gas from the internal combustion engine into the surge tank 21 as EGR gas via the EGR portion 26 . The EGR section 26 introduces the EGR gas into the surge tank 21 in a mode in which the openings of the branch pipes 23 are arranged in the surge tank 21 (horizontal direction in FIG. 5). there is The EGR portion 26 is provided so as to face the bottom wall 21C side (lower right in FIG. 5) in the direction in which the introduction portion 22 extends (vertical direction in FIG. 5).

As shown in FIGS. 6 and 7 , a cylindrical PCV pipe 27 is provided on the side peripheral wall 21B of the intake manifold 10 so as to communicate between the inside and outside of the surge tank 21 . The PCV pipe 27 forms part of a PCV passage for introducing blow-by gas into the surge tank 21, and functions as a blow-by gas section. The PCV pipe 27 extends in a direction along which the mounting flange 24 extends (horizontal direction in FIG. 6). The PCV pipe 27 is provided so as to face the top wall 21A side (upper right in FIG. 7) in the direction in which the introduction portion 22 extends (vertical direction in FIG. 7). When installing the intake manifold 10, the PCV pipe 27 is connected to a PCV hose (not shown) connected to the internal combustion engine. This makes it possible to introduce gas (including blow-by gas) in the crankcase of the internal combustion engine into the surge tank 21 via the PCV pipe 27 .

Air is introduced into the surge tank 21 of the intake manifold 10 through an introduction portion 22, and in addition, EGR gas is introduced through an EGR portion 26 (see FIG. 5) and a PCV pipe 27 is introduced. The gas inside the case is introduced through the Air in the surge tank 21 , EGR gas, and gas in the case are distributed and supplied to each cylinder of the internal combustion engine via each branch pipe 23 .

The intake manifold 10 of this embodiment has a structure in which the EGR gas and the case internal gas are introduced into the surge tank 21 . Therefore, when the blow-back phenomenon described above occurs, the EGR gas and the gas inside the case will flow back from the surge tank 21 into the throttle mechanism together with the intake air, albeit temporarily. It is known that the soot component contained in the EGR gas and the unburned fuel component and oil component contained in the case internal gas cause deposits. Therefore, it can be said that the blow-back phenomenon causes deposits inside the throttle mechanism. The formation of such deposits narrows the air flow path in the throttle mechanism and reduces the operating speed of the throttle mechanism.

Based on this point, in this embodiment, in order to suppress the occurrence of the above-described blowback phenomenon, a baffle plate 30 is provided inside the surge tank 21 of the intake manifold 10 as shown in FIGS. I have to. The baffle plate 30 and its surrounding structure will be described in detail below.

The baffle plate 30 protrudes from the top wall 21A of the surge tank 21 so as to extend along the periphery of the opening of the introduction portion 22 . The baffle plate 30 has a shape in which the inner peripheral wall of the introduction portion 22 extends inwardly of the surge tank 21 . The baffle plate 30 extends over 270 degrees around the opening of the introduction portion 22 .

As a portion where the baffle plate 30 is not provided (non-arranged portion), a portion on the side near the EGR portion 26 (upper side in FIG. 8) in the opening peripheral edge of the introduction portion 22 is defined. FIG. 8 shows a state in which the surge tank 21 is viewed in the direction in which the introduction portion 22 extends (more specifically, a state in which the first member 11 is viewed from below), and the line L1 in FIG. An EGR imaginary line connecting the center C1 of the opening of the introduction portion 22 and the center C2 of the opening of the EGR portion 26 in 21 is shown. As shown in FIG. 8, the baffle plate 30 is not provided in a portion overlapping the virtual EGR line L1 when the virtual EGR line L1 is drawn. That is, the baffle plate 30 is provided so as not to overlap the EGR virtual line L1 when the EGR virtual line L1 is drawn.

As shown in FIGS. 6 and 7, the baffle plate 30 is provided on the side (left side in FIG. 6) near the PCV pipe 27 in the peripheral edge of the opening of the introduction portion 22 . FIG. 6 shows a state in which the surge tank 21 is viewed in the direction in which the introduction portion 22 extends (more specifically, a state in which the second member 12 is viewed from above), and the line L2 in FIG. A PCV imaginary line connecting the center C1 of the opening of the introduction part 22 and the center C3 of the opening of the PCV pipe 27 in 21 is shown. As shown in FIG. 6, the baffle plate 30 is provided at a portion overlapping the PCV virtual line L2 when the PCV virtual line L2 is drawn. That is, the baffle plate 30 is provided in such a manner that the PCV virtual line L2 and a part of the baffle plate 30 overlap when the PCV virtual line L2 is drawn.

As shown in FIG. 8, in the introduction portion 22 of the intake manifold 10, the throttle mechanism is installed in a state in which the rotating shaft 41 of the throttle valve 40 extends along the extension direction of the mounting flange 24 (horizontal direction in FIG. 8). It is attached. When the throttle valve 40 is opened, the throttle valve 40 rotates in such a manner that the portion on the EGR section 26 side (upper side in FIG. 8) falls toward the surge tank 21 side (on the front side of the paper surface in FIG. 8). The baffle plate 30 is located at the downstream side of the rotating shaft 41 in the intake air flow direction at the opening peripheral edge of the introducing portion 22 in the surge tank 21 (specifically, in FIG. 8, the opening peripheral edge of the introducing portion 22 overlaps the rotating shaft 41). part) is provided.

7 and 8, the top wall 21A of the surge tank 21 has an outer peripheral wall portion 31 extending along the peripheral edge of the opening of the introduction portion 22. As shown in FIGS. The outer peripheral wall portion 31 extends in a cylindrical shape on the outer peripheral side of the baffle plate 30 . In the present embodiment, the introduction portion 22, the baffle plate 30, and the outer peripheral wall portion 31 are provided in a portion (flat portion 21D) where the inner surface of the top wall 21A of the surge tank 21 is flat. The baffle plate 30 protrudes to a position on the inner side of the surge tank 21 from the inner surface of the flat portion 21D.

The effects of the intake manifold 10 will be described below.
The blow-back phenomenon described above occurs as follows. As indicated by the black arrow in FIG. 9, part of the air introduced into the surge tank 21 from the introduction portion 22 collides with the inner wall surface of the surge tank 21 and then flows along the inner wall surface. and return to the vicinity of the opening peripheral edge of the introduction portion 22 . Then, the air that has returned to the vicinity of the opening peripheral edge of the introducing portion 22 enters the introducing portion 22 so as to be caught in the flow of air flowing from the introducing portion 22 into the surge tank 21 from the peripheral edge, and enters the introducing portion 22 upstream of the introducing portion 22. The blow-back phenomenon occurs by returning to the side intake passage (throttle mechanism).

In the intake manifold 10 , a baffle plate 30 protrudes from the periphery of the opening of the introduction portion 22 in the surge tank 21 . Therefore, as indicated by an arrow F1 in FIG. It can be bent in a direction along the flow of air flowing into the surge tank 21 (downward in FIG. 9). As a result, the flow of air returned to the vicinity of the periphery of the opening of the introduction portion 22 is less likely to flow toward the inside of the introduction portion 22, thereby suppressing the occurrence of the blow-back phenomenon. Therefore, according to the intake manifold 10 of the present embodiment, it is possible to suppress the occurrence of deposits due to the blowback phenomenon.

As shown in FIG. 10, the projection height (indicated by H in FIG. 10) of the baffle plate 30 from the inner surface of the flat portion 21D is determined based on the results of various experiments and simulations. The height (5 mm in this embodiment) capable of suppressing the blow-back phenomenon while maintaining the balance of the flow of the intake air is determined in advance.

In this embodiment, as shown in FIGS. 9 and 10, a portion of the top wall 21A of the surge tank 21 has a tubular shape extending along the peripheral edge of the opening of the introduction portion 22 on the outer peripheral side of the baffle plate 30. It is an outer peripheral wall portion 31 . As a result, in the intake manifold 10, the groove 32, whose inner surface is the outer peripheral surface of the baffle plate 30 and the inner peripheral surface of the outer peripheral wall portion 31, is formed along the peripheral edge of the opening of the introduction portion 22 on the outer peripheral side of the baffle plate 30. extended. Therefore, part of the flow of air that has flowed along the inner wall surface of the surge tank 21 and returned to the vicinity of the opening periphery of the introduction portion 22 enters the groove 32 as indicated by the black arrow in FIG. After being bent once in the direction of entering (upward in FIG. 10), it is bent in the direction of exiting from the groove 32 (downward in FIG. 10). As a result, the flow of air returning to the vicinity of the periphery of the opening of the introduction portion 22 is directed along the flow of air flowing into the surge tank 21 from the introduction portion 22, compared to the case where the outer peripheral wall portion 31 is not provided. A structure that makes it easy to face, that is, a structure that makes it difficult to face the inside of the introduction part 22 can be used.

Here, the intake manifold 10 has a structure in which EGR gas is introduced into the surge tank 21 . Therefore, for example, if a baffle plate with a high protruding height is protruded over the entire circumference of the opening peripheral edge of the introduction portion 22, it becomes difficult for the air introduced through the introduction portion 22 and the EGR gas introduced through the EGR portion 26 to mix. , there is a risk that variations in the amount of EGR gas distributed to each cylinder of the internal combustion engine will increase. In the intake manifold 10, the EGR gas is supplied to the inside of the surge tank 21 through the EGR portion 26 communicating with the side peripheral wall 21B of the surge tank 21, and the branch pipe 23 at the bottom wall 21C of the surge tank 21. It comes to flow in along the direction in which the openings are arranged (horizontal direction in FIG. 9). Therefore, it can be said that the distribution amount of EGR gas to each branch pipe 23 and thus to each cylinder of the internal combustion engine tends to vary, such that EGR gas flows into the branch pipe 23 closer to the EGR portion 26 more easily.

As shown in FIGS. 8 and 9, in the present embodiment, the baffle plate 30 is not provided at the side near the EGR section 26 on the peripheral edge of the opening of the introduction section 22 in the surge tank 21 . Therefore, as indicated by the white arrow in FIG. can be made Since the flow of air (arrow F2 in FIG. 9) and the flow of EGR gas (arrow F3 in FIG. 9) flowing from the EGR section 26 into the surge tank 21 can collide, the air and the EGR Mixing with gas is facilitated.

Further, as described above, the throttle valve 40 (FIG. 8) rotates in such a manner that the portion closer to the EGR section 26 falls toward the surge tank 21 when the valve is opened. Therefore, it can be said that the force of the air passing through the introduction portion 22 tends to become stronger in the portion near the EGR portion 26 . In the intake manifold 10 of the present embodiment, the baffle plate 30 is not provided in the portion near the EGR section 26, that is, in the portion where the air flow tends to be strong. Therefore, the air can be flowed into the surge tank 21 vigorously and over a wide range through this portion. As a result, the intake air, the EGR gas, and the gas inside the case are easily mixed in the surge tank 21 .

As described above, according to the present embodiment, air and EGR gas can be easily mixed in the surge tank 21, so that variation in the amount of EGR gas distributed to each cylinder of the internal combustion engine can be suppressed.

Moreover, the flow of EGR gas flowing into the surge tank 21 from the EGR portion 26 and heading toward the introduction portion 22 (arrow F3 in FIG. 9) is different from the flow of air flowing in from the introduction portion 22 (arrow F2 in FIG. 9). Therefore, it is possible to adopt a structure in which it is difficult for the EGR gas to directly enter the introduction portion 22 . Furthermore, since the EGR portion 26 is provided so as to face the bottom wall 21C side in the direction in which the introduction portion 22 extends, the EGR gas introduced into the surge tank 21 from the EGR portion 26 is directed in the direction in which the introduction portion 22 extends. It is possible to suppress direct movement toward the top wall 21A side, that is, toward the non-arranged portion where the baffle plate 30 is not arranged. As a result, it is possible to prevent the EGR gas introduced into the surge tank 21 from entering the introduction portion 22 via the non-arranged portion.

In this embodiment, as shown in FIGS. 6 and 7, a baffle plate 30 is provided on the side near the PCV pipe 27 (on the left side in FIG. 6) in the periphery of the opening of the introduction portion 22 . Therefore, the case internal gas flowing from the PCV pipe 27 into the surge tank 21 and heading toward the introduction portion 22 is prevented from directly entering the introduction portion 22 . Furthermore, the PCV pipe 27 is provided so as to face the top wall 21A side in the direction in which the introduction portion 22 extends. Therefore, the case internal gas introduced into the surge tank 21 from the PCV pipe 27 is arranged so as to approach the introduction portion 22 of the top wall 21A, in other words, to flow away from the opening of the branch pipe 23 in the bottom wall 21C. become. As a result, the gas in the case can be appropriately mixed with the intake air in the surge tank 21 and then distributed to the branch pipes 23 and, in turn, to the cylinders of the internal combustion engine.

Further, in the intake manifold 10 of the present embodiment, the throttle valve 40 (FIG. 8) is arranged upstream of the introduction portion 22, so that the rotating shaft 41 of the throttle valve 40 rotates the air in the intake passage of the internal combustion engine. obstruct the flow. For this reason, in the portion of the periphery of the opening of the introduction portion 22 in the surge tank 21 that hits the downstream side of the rotating shaft 41 of the throttle valve 40, the flow velocity of the air toward the surge tank 21 tends to be slow, and the blow-back phenomenon occurs. Easy to say. Therefore, deposits are likely to occur near the rotation shaft 41 of the throttle valve 40, and the occurrence of deposits in this portion may cause the throttle valve 40 to malfunction.

In the present embodiment, as shown in FIG. 8, a baffle plate 30 is arranged at a portion of the opening peripheral edge of the introduction portion 22 that is located downstream of the rotating shaft 41 of the throttle valve 40 . Therefore, the baffle plate 30 suppresses the blow-back phenomenon in this portion. As a result, the occurrence of deposits on the rotating shaft 41 of the throttle valve 40 is suppressed, so that the occurrence of malfunction of the throttle valve 40 is suppressed.

As described above, according to this embodiment, the following effects can be obtained.
(1) A baffle plate 30 extending along the periphery of the opening of the introduction portion 22 is protruded from the inner wall of the surge tank 21 . Therefore, it is possible to suppress the generation of deposits due to the blow-back phenomenon. Moreover, an EGR imaginary line L1 connecting the center C1 of the opening of the introduction portion 22 and the center C2 of the opening of the EGR portion 26 inside the surge tank 21 while viewing the surge tank 21 in the direction in which the introduction portion 22 extends is drawn. In this case, the baffle plate 30 is not provided on the EGR imaginary line L1. Therefore, variations in the amount of EGR gas distributed to each cylinder of the internal combustion engine can be suppressed.

(2) The EGR portion 26 is provided so as to face the bottom wall 21C side in the direction in which the introduction portion 22 extends. Therefore, it is possible to prevent the EGR gas introduced into the surge tank 21 from entering the introduction portion 22 through the non-arranged portion where the baffle plate 30 is not arranged.

(3) A PCV imaginary line L2 that connects the center C1 of the opening of the introduction portion 22 and the center C3 of the opening of the PCV pipe 27 in the surge tank 21 when the surge tank 21 is viewed in the direction in which the introduction portion 22 extends. A baffle plate 30 is provided in a portion overlapping with the PCV imaginary line L2 when drawn. Therefore, the case internal gas flowing from the PCV pipe 27 into the surge tank 21 and heading toward the introduction portion 22 is prevented from directly entering the introduction portion 22 .

(4) The PCV pipe 27 is provided so as to face the top wall 21A side in the direction in which the introduction portion 22 extends. Therefore, the gas in the case can be appropriately mixed with the intake air in the surge tank 21 and then distributed to each branch pipe 23 and thus to each cylinder of the internal combustion engine.

(5) The top wall 21A of the surge tank 21 has a cylindrical outer wall portion 31 extending along the periphery of the opening of the introduction portion 22 on the outer peripheral side of the baffle plate 30 . Therefore, compared to the case without the outer peripheral wall portion 31, the flow of air returning to the vicinity of the opening peripheral edge of the introduction portion 22 is directed in the direction along the flow of air flowing into the surge tank 21 from the introduction portion 22. In other words, it is possible to adopt a structure in which it is difficult to move toward the inside of the introduction portion 22 .

<Modification>
It should be noted that the above embodiment may be modified as follows.
- The protrusion height of the baffle plate 30 from the flat portion (flat portion 21D) of the top wall 21A of the surge tank 21 can be arbitrarily changed.

The EGR portion 26 may be provided so as to extend in a direction orthogonal to the direction in which the introduction portion 22 extends, or may be provided so as to face the top wall 21A side in the direction in which the introduction portion 22 extends.
- The PCV pipe 27 may be provided so as to extend in a direction orthogonal to the direction in which the introduction portion 22 extends, or may be provided so as to face the bottom wall 21C side in the direction in which the introduction portion 22 extends.

・The extension angle of the baffle plate 30 at the opening peripheral edge of the introduction part 22 is not limited to 270 degrees, and can be arbitrarily changed to an angle slightly smaller than 270 degrees or an angle slightly larger than 270 degrees. can. In short, when the EGR virtual line L1 (see FIG. 8) is drawn, the baffle plate 30 is not provided in the non-arranged portion including the portion overlapping the EGR virtual line L1, and the non-arranged portion A baffle plate 30 may be provided in the other portion.

- The intake manifold of the above embodiment can also be applied to an intake manifold that does not have the PCV pipe 27 .

DESCRIPTION OF SYMBOLS 10... Intake manifold, 11... First member, 12... Second member, 13... Third member, 14... Fourth member, 21... Surge tank, 21A... Top wall, 21B... Side peripheral wall, 21C... Bottom wall, 21D Flat portion 22 Introduction portion 23 Branch pipe 24 Mounting flange 24A Connection surface 25 Fixed portion 26 EGR portion 27 PCV pipe 30 Baffle plate 31 Peripheral wall portion 32... concave groove, 40... throttle valve, 41... rotating shaft.

Claims (5)

a surge tank having a top wall, a bottom wall, and an annular side peripheral wall erected from peripheral edges of the top wall and the bottom wall;
a cylindrical introduction part whose one end is communicated with the top wall and introduces air into the surge tank;
a plurality of branch pipes separately communicating with the bottom wall to distribute air in the surge tank;
a cylindrical EGR portion, one end of which is communicated with the side peripheral wall, and which introduces EGR gas into the surge tank in a manner in which the EGR gas is introduced along the direction in which the openings of the branch pipes are arranged in the surge tank;
a baffle plate projecting from the inner surface of the top wall in a manner extending along the peripheral edge of the opening of the introduction part,
The baffle plate draws an EGR imaginary line connecting the center of the opening of the introduction portion and the center of the opening of the EGR portion inside the surge tank when the surge tank is viewed in the direction in which the introduction portion extends. In this case, the intake manifold is not provided in a non-arranged portion including a portion overlapping with the EGR virtual line, but is provided in a portion other than the same non-arranged portion. The intake manifold according to claim 1, wherein the EGR portion is provided so as to face the bottom wall side in the direction in which the introduction portion extends. The intake manifold includes a cylindrical blow-by gas portion connected at one end to the side peripheral wall and introducing blow-by gas into the surge tank,
The baffle plate draws an imaginary PCV line connecting the center of the opening of the introduction portion and the center of the opening of the blow-by gas portion inside the surge tank when the surge tank is viewed in the direction in which the introduction portion extends. 3. The intake manifold according to claim 1, wherein the intake manifold is provided in a portion overlapping with the PCV phantom line when the intake manifold is closed. 4. The intake manifold according to claim 3, wherein the blow-by gas portion is provided so as to face the top wall side in the direction in which the introduction portion extends. The intake manifold according to any one of claims 1 to 4, wherein the inner wall of the surge tank has a cylindrical outer wall portion extending along the peripheral edge of the opening of the introduction portion on the outer peripheral side of the baffle plate.

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