Intake Manifold

Abstract

To provide an intake manifold capable of accurately adjusting a flow of inlet gas from a gas introducing portion to a manifold body.SOLUTION: A gas introducing portion 25 has a structure in which a first member 11 and a second member 12 divided in an extending direction are integrally joined. At a position that is a communication part between a gas introducing portion 25 and an air introducing portion 22 on an inner surface of the first member 11, a blocking wall portion 111 of a shape blocking a part of the gas introducing portion 25 is protrusively provided. In a part blocked by the blocking wall portion 111 inside the gas introducing portion 25, a gap is formed between a projecting end of the blocking wall portion 111 and an inner surface of the second member 12. A channel resistance member 45 is provided inside the gas introducing portion 25. The channel resistance member 45 has a shape in which the channel resistance of the first part 25U on the side on which the gap is formed is larger than the channel resistance of the second part 25 on the side on which the gap is not formed in the gas introducing portion 25.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to an intake manifold for an internal combustion engine. Background Art

[0002] An internal combustion engine is provided with an intake manifold forming part of an intake system (see Patent Document 1). This intake manifold includes a surge tank, an air introduction portion communicating the inside and outside of the surge tank, and a plurality of branch pipes each having one end connected to the surge tank. A portion of the intake passage of the internal combustion engine on the upstream side in the intake flow direction is connected to the air introduction portion. The plurality of branch pipes are connected to respective intake ports of the internal combustion engine. With such an intake manifold, air drawn into the intake passage is distributed to each cylinder of the internal combustion engine.

[0003] It has also been proposed to integrally provide an EGR portion for introducing a part of exhaust gas (so-called EGR gas) from the internal combustion engine into the intake manifold. The EGR portion constitutes a part of an EGR passage for recirculating a part of exhaust gas in an exhaust passage of the internal combustion engine to the intake passage. A portion of the EGR passage on the upstream side in the EGR gas flow direction is connected to the EGR portion. Prior Art Documents Patent Documents

[0004] Patent Document 1 Japanese Unexamined Patent Publication No. 2017-96176 Summary of the Invention Problems to be Solved by the Invention

[0005] Here, in order to optimize the inflow mode of EGR gas from the EGR portion into the manifold body (specifically, the air introduction portion, the surge tank, and the branch pipes), it is conceivable to provide a closing wall portion that blocks a part of the EGR portion at a connection portion with the manifold body inside the EGR portion.

[0006] An intake manifold having such an EGR section can be formed as follows: The EGR passage is divided into a first and second section along its extension direction, creating a split structure. The first section is made of a material with a closed wall protruding from its inner surface. The intake manifold is then formed by joining the first and second sections together.

[0007] In intake manifolds with this structure, a gap may form where the two divided parts are joined, specifically where the tip of the closing wall of the first divided part and the inner surface of the second divided part face each other. In this case, EGR gas leaks out through the gap. When adjusting the flow of EGR gas from the EGR section to the manifold body, the leaked EGR gas contributes to a decrease in adjustment accuracy.

[0008] Furthermore, the above problem is not limited to intake manifolds with an integrated EGR section, but also occurs in intake manifolds with an integrated blow-by gas section for introducing combustion gases (so-called blow-by gases) that have leaked from the combustion chamber of the internal combustion engine into the crankcase. The above problem also occurs in intake manifolds with an integrated purge gas section for introducing evaporated fuel (so-called purge gases) from the fuel tank of the internal combustion engine. [Means for solving the problem]

[0009] An intake manifold for solving the above problems comprises a surge tank, an air introduction section connected to the surge tank for introducing air into the surge tank, and a manifold body having a plurality of branch pipes each connected to the surge tank, and a gas introduction section connected to the manifold body for introducing an introduction gas other than air into the manifold body, wherein the gas introduction section has a structure in which a first divided body and a second divided body, which are divided along the extending direction of the gas introduction section, are integrally joined, and a closing wall portion is provided protruding from the inner surface of the first divided body at a position corresponding to the communication portion between the gas introduction section and the manifold body, with a shape that blocks a part of the gas introduction section. The portion of the gas introduction section that is blocked by the blocking wall has a structure in which the tip of the blocking wall and the inner surface of the second divided body are arranged opposite each other, such that a gap is formed between the tip of the blocking wall and the inner surface of the second divided body, and when viewed from the extending direction, the portion of the gas introduction section on the side where the gap is formed is designated as the first portion, and the portion of the gas introduction section on the side where the gap is not formed is designated as the second portion, a flow resistance member is provided inside the gas introduction section that has a shape that makes the flow resistance of the first portion greater than the flow resistance of the second portion.

[0010] According to the above configuration, a blocking wall can be provided at the communication point between the gas inlet and the manifold body. Through the setting of this blocking wall, the gas can be introduced from the gas inlet into the manifold body in a desired manner.

[0011] Furthermore, by providing a flow resistance member inside the gas inlet, the introduced gas can flow more easily to the second portion where the gap is not formed, while making it more difficult for the introduced gas to flow to the first portion where the gap is formed. This prevents the introduced gas from leaking through the gap. As a result, the flow of introduced gas from the gas inlet to the manifold body can be precisely adjusted. [Brief explanation of the drawing]

[0012] [Figure 1] This is a front view of an intake manifold according to one embodiment. [Figure 2] This is a rear view of the intake manifold. [Figure 3] This is a side view of the intake manifold. [Figure 4] This is a disassembled side view of the intake manifold. [Figure 5] This is a side cross-sectional view of the intake manifold. [Figure 6] This is a front view of the second and third components of the intake manifold. [Figure 7] This is a rear view of the first component of the intake manifold. [Figure 8] This is a cross-sectional view of the gas inlet and its surrounding area along line 8-8 in Figure 2. [Figure 9] This is a cross-sectional view of the gas inlet and its surrounding area along the line 9-9 in Figure 8. [Figure 10] This is a cross-sectional view of the air intake section along the line 10-10 in Figure 9. [Modes for carrying out the invention]

[0013] Hereinafter, one embodiment of the intake manifold will be described with reference to Figures 1 to 10. In this embodiment, the vertical direction in Figure 1 will be considered the vertical direction of the intake manifold 10, the left-right direction in Figure 1 will be considered the left-right direction of the intake manifold 10, and the direction perpendicular to the plane of the paper in Figure 1 will be considered the front-to-back direction of the intake manifold 10.

[0014] As shown in FIGS. 1 to 5, the intake manifold 10 is constituted by three divided bodies (a first member 11, a second member 12, and a third member 13) divided in the front-rear direction. The three divided bodies are arranged in the order of the first member 11, the second member 12, and the third member 13 from the front side. All of the first member 11, the second member 12, and the third member 13 are formed of a hard synthetic resin material. The intake manifold 10 has a structure in which the first member 11, the second member 12, and the third member 13 are stacked (in the state shown in FIG. 3), and these members 11 to 13 are fixed to each other by vibration welding.

[0015] The intake manifold 10 includes a surge tank 21, an air introduction portion 22, a plurality of (three in the present embodiment) branch pipes 23, a mounting flange 24, and a gas introduction portion 25. In the present embodiment, the surge tank 21, the air introduction portion 22, and the plurality of branch pipes 23 constitute a manifold main body.

[0016] <Surge Tank> The surge tank 21 constitutes a central portion of the intake manifold 10. The surge tank 21 functions as a volume portion for temporarily storing air.

[0017] <Air Introduction Portion> As shown in FIGS. 2, 3, 6 and 7, the air introduction portion 22 has a cylindrical shape with one end connected to the surge tank 21. The interior of the air introduction portion 22 constitutes a main passage 22M that communicates the interior of the surge tank 21 with the exterior of the intake manifold 10. In the intake manifold 10, air is introduced into the surge tank 21 via the main passage 22M of the air introduction portion 22.

[0018] The air introduction portion 22 has an inlet portion 31 and a curved portion 32. The inlet section 31 constitutes the upstream portion of the air intake section 22 in the direction of intake airflow. The upstream end of the inlet section 31 in the direction of intake airflow is a fixed section 221 to which the upstream portion of the intake passage of the internal combustion engine (specifically, the throttle mechanism) is fixed. The inlet section 31 extends in a substantially straight line forward and diagonally downward from the fixed section 221.

[0019] The curved section 32 constitutes the downstream portion of the air intake section 22 in the direction of intake air flow. The curved section 32 extends in a manner that connects the downstream end of the inlet section 31 in the direction of intake air flow with the left portion of the surge tank 21. Specifically, the curved section 32 starts from the downstream end of the inlet section 31 in the direction of intake air flow and curves to the right. The downstream end of the curved section 32 in the direction of intake air flow (more specifically, the right portion of the curved section 32) is in communication with the left portion of the surge tank 21.

[0020] <State detection unit> As shown in Figures 2, 3, and 6, the air intake section 22 is provided with a state detection section 26. The state detection section 26 is cylindrical and extends backward from the rear wall (hereinafter referred to as the rear wall 22R) of the air intake section 22. The front end of the state detection section 26 is open on the inner surface of the rear wall 22R of the air intake section 22. A pressure sensor 27 is attached to the rear end of the state detection section 26. The rear end of the state detection section 26 is closed by the pressure sensor 27. The internal pressure of the state detection section 26 is detected by this pressure sensor 27 as the internal pressure of the intake manifold 10 (specifically, the main passage 22M).

[0021] <Branch pipe> As shown in Figures 2, 5, and 6, the multiple branch pipes 23 are individually connected to the lower part of the surge tank 21. The multiple branch pipes 23 are distribution passages that distribute the air inside the surge tank 21. Each branch pipe 23 extends from the lower rear to the upper front of the intake manifold 10, curving in a convex shape toward the rear. The base end 231 portion of each branch pipe 23 is formed integrally with the rear wall (hereinafter referred to as the rear wall 21R) and the upper wall of the surge tank 21 without any gaps. The base end 231 of each branch pipe 23 opens on the inner surface of the rear wall 21R of the surge tank 21. The tip 232 of each branch pipe 23 opens toward the outside.

[0022] <Mounting flange> As shown in Figures 1, 3, and 5, the mounting flange 24 is integrally provided on the tip 232 of each branch pipe 23. The mounting flange 24 extends in the direction in which the tips 232 of the two branch pipes 23 are aligned. The mounting flange 24 is plate-shaped and extends in the vertical and horizontal directions. By fixing this 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.

[0023] As shown in Figures 2, 6, and 7, the intake manifold 10 has through holes 28 and 29 used for fixing the mounting flange 24. Specifically, as shown in Figure 7, the second member 12 has a boss portion 281 that protrudes rearward from its inner surface and a through hole 28 that extends in the front-rear direction, passing through the boss portion 281. Also, as shown in Figure 6, the third member 13 has a boss portion 291 that protrudes forward from its inner surface and a through hole 29 that extends in the front-rear direction, passing through the boss portion 291. As shown in Figures 2, 6, and 7, the through hole 28 of the second member 12 and the through hole 29 of the third member 13 are connected in such a way that they form a single through hole extending in the front-rear direction.

[0024] As shown in Figures 1 and 3, the intake manifold 10 is provided with reinforcing ribs 50. The reinforcing ribs 50 protrude from the outer wall of the mounting flange 24, the outer wall of the branch pipe 23, and the outer wall of the surge tank 21. The reinforcing ribs 50 are plate-shaped and extend in the front-rear and up-down directions. The reinforcing ribs 50 extend from the mounting flange 24 through the tip of the branch pipe 23 to the surge tank 21. Reinforcing ribs 50 are provided separately for each of the three branch pipes 23.

[0025] <Gas inlet section> As shown in Figures 1 to 3, the gas inlet section 25 is basically cylindrical in shape, extending in the left-right direction. As shown in Figures 6 to 9, one end of the gas inlet section 25 (specifically, the right end) is connected to the peripheral wall of the air inlet section 22. The gas inlet section 25 has a structure through which a portion of the exhaust gas from the internal combustion engine (so-called EGR gas) passes. The gas inlet section 25 is for introducing EGR gas into the airflow portion inside the intake manifold 10 (in this embodiment, the main passage 22M of the air inlet section 22). In this embodiment, the EGR gas corresponds to the introduction gas other than air.

[0026] As shown in Figures 1, 8, and 9, the gas introduction section 25 has an upstream section 41, a downstream section 43, an opening 44, and a flow path resistance member 45. <Upstream> The upstream section 41 constitutes the upstream side (specifically, the left side) of the gas inlet section 25 in the direction of EGR gas flow. The upstream section 41 extends linearly in the left-right direction. The left end of the upstream section 41, which is the upstream end in the direction of EGR gas flow, is a fixing section 251 to which the upstream portion of the EGR passage in the direction of EGR gas flow (specifically, the EGR pipe) is fixed. The right end of the upstream section 41, which is the downstream end in the direction of EGR gas flow, is connected to the downstream section 43.

[0027] <Downstream> The downstream section 43 constitutes the portion of the gas inlet section 25 that is downstream in the direction of EGR gas flow (specifically, the right side). The right end of the downstream section 43, which is the downstream end in the direction of EGR gas flow, is connected to the peripheral wall of the air inlet section 22, more specifically, to the outer side in the curvature direction of the curved section 32. The downstream section 43 has a flared shape in which the passage cross-sectional area increases as it moves away from the upstream section 41. Specifically, the distance between opposing walls in the vertical direction of the peripheral wall of the downstream section 43 gradually increases as it moves away from the upstream section 41, that is, as it approaches the air inlet section 22. In addition, the distance between opposing walls in the front-rear direction of the peripheral wall of the downstream section 43 remains approximately constant.

[0028] <Sub-passage> In this embodiment, the interior of the downstream section 43 constitutes the sub-passage 43S. As shown in Figure 9, the sub-passage 43S has a shape that extends along the main passage 22M of the air intake section 22. Specifically, the sub-passage 43S has a shape that extends in the vertical and longitudinal directions.

[0029] The upstream section 41 is connected to the sub-passage 43S in such a manner that it discharges EGR gas in a direction perpendicular to the extension direction LS (LS is not shown in the figure) of the sub-passage 43S (in this embodiment, the left-right direction). The upstream section 41 is also connected to the middle portion of the sub-passage 43S in the extension direction LS. Specifically, the upstream section 41 is connected to the middle portion of the sub-passage 43S in the vertical direction. As a result, the upper part of the sub-passage 43S extends above the communication portion between the sub-passage 43S and the upstream section 41. In this embodiment, some of the EGR gas flowing into the sub-passage 43S from the communication portion flows upward above the communication portion and then returns downward. Therefore, the velocity of the EGR gas in the sub-passage 43S is kept lower compared to a configuration where the upstream section 41 is connected to the upper end of the sub-passage 43S. Consequently, the velocity of the EGR gas flowing from the sub-passage 43S into the main passage 22M is kept low.

[0030] As shown in Figures 8 to 10, the opening 44 is provided in the peripheral wall of the air inlet 22. The opening 44 is a through hole that penetrates the peripheral wall of the air inlet 22. In this embodiment, the main passage 22M of the air inlet 22 and the secondary passage 43S of the gas inlet 25 are connected through this opening 44. The opening 44 is provided at the lower end 431 of the secondary passage 43S, which is the end on the surge tank 21 side in the extension direction LS of the secondary passage 43S. As a result, the secondary passage 43S extends in such a manner that its lower end 431 and the main passage 22M merge. In this embodiment, the portion of the secondary passage 43S other than the lower end 431 is closed off from the main passage 22M.

[0031] The opening 44 is provided on the outer portion of the curved portion 32 in the curvature direction of the peripheral wall of the air introduction section 22. The opening 44 is located on the outer side of the curved portion 32 in the curvature direction and opens on the inner surface of the curved portion 32. In this embodiment, the sub-passage 43S of the gas introduction section 25 is connected to the main passage 22M of the air introduction section 22 in the outer portion of the curved portion 32 in the curvature direction.

[0032] As shown in Figures 9 and 10, the opening shape of the opening 44, which is the confluence portion where the main passage 22M and the sub-passage 43S merge, is an elongated hole in the extension direction LM (LM is not shown) of the air introduction section 22 (specifically, the main passage 22M). More specifically, the opening shape of the opening 44 is tapered, with the portion PB closer to the surge tank 21 being narrower than the portion PU further away from the surge tank 21 in the extension direction LM of the main passage 22M.

[0033] As shown in Figures 6 and 7, the opening 44 is located closer to the surge tank 21 in the extension direction LM than the opening of the state detection unit 26 on the inner surface of the air intake unit 22, i.e., it is located downstream in the intake air flow direction. In other words, the state detection unit 26 is located further away from the surge tank 21 in the extension direction LM than the opening 44, i.e., upstream in the intake air flow direction.

[0034] The gas introduction section 25 has a structure in which the first member 11 and the second member 12 are integrally joined. Specifically, as shown in Figures 3 and 4, the intake manifold 10 has a first member 11 and a second member 12 that are divided along the extension direction LG (LG is not shown, in this embodiment the left-right direction) of the gas introduction section 25. The first member 11 includes the entire upstream section 41 of the gas introduction section 25 and the front part of the downstream section 43. The second member 12 includes the rear part of the downstream section 43 of the gas introduction section 25. In this embodiment, the first member 11 and the second member 12 are joined to each other in a joined state. In this way, the passage-shaped gas introduction section 25 is partitioned inside the intake manifold 10. In this embodiment, the first member 11 corresponds to the first divided body, and the second member 12 corresponds to the second divided body.

[0035] As shown in Figures 7 to 10, a blocking wall portion 111 is provided protruding from the inner surface of the first member 11. The blocking wall portion 111 is provided at a position on the inner surface of the first member 11 corresponding to the communication portion between the gas introduction portion 25 and the air introduction portion 22. The blocking wall portion 111 has a shape that blocks a part of the gas introduction portion 25 at the communication portion. The blocking wall portion 111 constitutes a part of the wall portion of the gas introduction portion 25 and also constitutes a part of the peripheral wall of the air introduction portion 22. The shape of the blocking wall portion 111 is such that the main passage 22M inside the air introduction portion 22 extends with substantially the same cross-sectional shape and substantially the same cross-sectional area. As a result, although a part of the peripheral wall of the air introduction portion 22 is composed of the blocking wall portion 111, air flows smoothly inside the air introduction portion 22 (more specifically, the main passage 22M).

[0036] As shown in Figures 8 and 10, the portion of the gas introduction section 25 that is blocked by the blocking wall 111 has a structure in which the tip of the blocking wall 111 and the inner surface of the second member 12 are positioned opposite each other. Therefore, in this portion, a gap W is formed between the tip of the blocking wall 111 and the inner surface of the second member 12.

[0037] <Flow resistance component> As shown in Figures 6, 7, and 9, a flow resistance member 45 is provided inside the downstream portion 43 of the gas introduction section 25.

[0038] Figure 8 shows the internal structure of the gas inlet 25 when viewed from the extension direction LG (specifically, the left side) of the gas inlet 25. As shown in Figure 8, in this embodiment, the upper part of the gas inlet 25 where the gap W is formed is defined as the first part 25U when viewed from the extension direction LG of the gas inlet 25. The lower part of the gas inlet 25 where the gap W is not formed is defined as the second part 25B when viewed from the extension direction LG of the gas inlet 25.

[0039] As shown in Figures 6, 7, and 9, the flow resistance member 45 is shaped to make the flow resistance of the EGR gas within the first portion 25U greater than the flow resistance of the EGR gas within the second portion 25B. The flow resistance member 45 is composed of a first projection 112 provided on the first member 11 and a second projection 121 provided on the second member 12.

[0040] <First Protrusion> As shown in Figures 7 to 9, the portion of the first member 11 that constitutes the downstream portion 43 of the gas introduction section 25 has a roughly C-shape in cross-section that opens towards the rear (see Figure 8) and extends in the left-right direction. The first projection 112 is provided protruding from the inner surface of the first member 11. The first projection 112 is roughly flat and extends in the vertical and front-rear directions. The front and upper ends of the first projection 112 are integral with the inner surface of the first member 11. The lower end of the first projection 112 is spaced apart from the inner surface of the first member 11.

[0041] <Second Pierce> As shown in Figures 6, 8, and 9, the portion of the second member 12 that constitutes the downstream portion 43 has a roughly C-shaped cross-section that opens forward (see Figure 8) and extends in the left-right direction. The second projection 121 is provided protruding from the inner surface of the second member 12. The second projection 121 is a flat plate shape that extends in the vertical and front-rear directions. The rear end of the second projection 121 is integral with the inner surface of the second member 12. The upper and lower ends of the second projection 121 are spaced apart from the inner surface of the second member 12.

[0042] As shown in Figures 6, 7, and 9, the first projection 112 and the second projection 121 are arranged alternately in the extending direction LG of the gas introduction section 25. In this embodiment, the first projection 112, the second projection 121, and the closing wall section 111 are arranged in the order of the first projection 112, the second projection 121, and the closing wall section 111 from the upstream side (left side in Figure 9) in the EGR gas flow direction. The first projection 112 and the second projection 121 extend parallel to each other. In this embodiment, the first projection 112 and the second projection 121 are provided in such a manner that the rear portion of the first projection 112 and the front portion of the second projection 121 overlap when viewed from the extending direction LG of the gas introduction section 25 (see Figures 3 and 4).

[0043] The flow resistance member 45 has a so-called labyrinth structure in which the first projection 112 and the second projection 121 form a maze-like flow path. The maze-like flow path is composed of (flow path A) to (flow path E) as described below. (flow path A) A flow path consisting of the gap between the rear end of the first projection 112 and the inner surface of the second member 12. (flow path B) A flow path consisting of the gap between the right surface of the first projection 112 and the left surface of the second projection 121. (flow path C) A flow path consisting of the gap between the front end of the second projection 121 and the inner surface of the first member 11. (flow path D) A flow path consisting of the gap between the upper end of the second projection 121 and the inner surface of the first member 11. (flow path E) A flow path consisting of the gap between the right surface of the second projection 121 and the left surface of the closing wall portion 111.

[0044] In this embodiment, the flow resistance member 45 (specifically, the first projection 112 and the second projection 121) is provided on the first portion 25U which constitutes the upper part of the gas introduction section 25, while it is not provided on the second portion 25B which constitutes the lower part of the gas introduction section 25. That is, the flow resistance member 45 is provided only on the first portion 25U of the two portions 25U and 25B. In this embodiment, the flow resistance member 45 is also provided at a position on the side of the closing wall portion 111 rather than the center of the extension direction LG in the gas introduction section 25 (indicated as "PA" in Figure 9).

[0045] As shown in Figures 9 and 10, in the intake manifold 10 of this embodiment, regulated air (indicated by arrow GA in the figures) is introduced into the surge tank 21 via the air inlet 22 through the operation of the throttle mechanism. EGR gas (indicated by arrow GE in the figures) is also introduced into the surge tank 21 via the gas inlet 25. The air and EGR gas introduced into the surge tank 21 are then distributed and supplied to each intake port of the internal combustion engine via each branch pipe 23 (Figure 5).

[0046] <Effects and Effects> The following describes the effects and benefits of the intake manifold 10 of this embodiment. (1) In the intake manifold 10 of this embodiment, a blocking wall portion 111 is provided in the communication portion between the gas inlet portion 25 and the air inlet portion 22, with a shape that blocks a part of the gas inlet portion 25. Therefore, by setting the shape of this blocking wall portion 111, the shape and position of the opening 44 that connects the main passage 22M of the air inlet portion 22 and the secondary passage 43S of the gas inlet portion 25 can be set with a high degree of freedom. Thus, EGR gas can be introduced from the gas inlet portion 25 to the air inlet portion 22 in a desired manner (inflow amount, inflow position).

[0047] Furthermore, in the intake manifold 10 of this embodiment, a flow resistance member 45 is provided inside the gas introduction section 25. The flow resistance member 45 is shaped to make the flow resistance of the upper first section 25U, where the gap W is formed, greater than the flow resistance of the lower second section 25B, where the gap W is not formed inside the gas introduction section 25.

[0048] By providing such flow resistance members 45, EGR gas can flow more easily into the lower second portion 25B where the gap W is not formed inside the gas introduction section 25, while making it more difficult for EGR gas to flow into the upper first portion 25U where the gap W is formed. In this embodiment, the first portion 25U is structured so that almost no EGR gas flows through it. As a result, the flow rate of EGR gas in the first portion 25U can be reduced, and therefore the amount of EGR gas that passes through the first portion 25U and reaches the gap W can be reduced. Therefore, according to this embodiment, although a gap W is formed between the protruding end (rear end) of the closing wall portion 111 and the inner surface of the second member 12, leakage of EGR gas from the sub-passage 43S of the gas introduction section 25 to the main passage 22M of the air introduction section 22 through this gap W can be suppressed. Thus, the flow of introduced gas from the gas introduction section 25 to the air introduction section 22 can be precisely adjusted.

[0049] (2) In this embodiment, the flow resistance member 45 has a plate-shaped first projection 112 protruding from the inner surface of the first member 11 and a plate-shaped second projection 121 protruding from the inner surface of the second member 12. The flow resistance member 45 has a labyrinth structure in which the first projection 112 and the second projection 121 are arranged alternately in the extending direction LG of the gas introduction section 25. According to this embodiment, by providing a flow resistance member 45 with such a labyrinth structure, the flow resistance of the EGR gas flow in the first portion 25U of the gas introduction section 25 can be adjusted to a desired value.

[0050] (3) In this embodiment, the flow resistance member 45 is provided only in the first portion 25U of the second portion 25B within the gas introduction section 25. According to this embodiment, compared to the case in which the flow resistance member 45 is also provided in the second portion 25B within the gas introduction section 25, the flow resistance of the EGR gas flow in the second portion 25B can be reduced. As a result, the EGR gas can flow more easily through the second portion 25B within the gas introduction section 25, and consequently, the EGR gas can flow less easily through the first portion 25U within the gas introduction section 25. Therefore, leakage of EGR gas from the gas introduction section 25 to the air introduction section 22 through the gap W can be effectively suppressed.

[0051] (4) In this embodiment, the flow resistance member 45 is provided in the gas introduction section 25 at a position closer to the closing wall 111 than to the central PA in the extending direction LG. According to this embodiment, compared to the case where the flow resistance member 45 is provided at a position further away from the closing wall 111 than to the central PA in the extending direction LG, the flow resistance member 45 can be provided at a position closer to the closing wall 111 (more specifically, the gap W). As a result, the effect of increasing the flow resistance of the first section 25U by the flow resistance member 45 is exerted further downstream in the direction of EGR gas flow, making it possible to create a structure in which it is difficult for EGR gas to reach the gap W.

[0052] <Example of changes> The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0053] The state detection unit 26 and the pressure sensor 27 can be omitted. • The reinforcing rib 50 can be omitted. Multiple first protrusions 112 can be provided on the inner surface of the first member 11. It is also possible to provide multiple second protrusions 121 on the inner surface of the second member 12. In this case, the first protrusions 112 and the second protrusions 121 should be arranged alternately in the extending direction LG of the gas introduction section 25.

[0054] - Instead of providing the flow resistance member 45 at a position closer to the closing wall portion 111 than the central PA in the extending direction LG of the gas introduction section 25, it may be provided at a position corresponding to the central PA in the extending direction LG. Alternatively, instead of providing the flow resistance member 45 at a position closer to the closing wall portion 111 than the central PA in the extending direction LG of the gas introduction section 25, it may be provided at a position further away from the closing wall portion 111 than the central PA in the extending direction LG.

[0055] In addition to providing the flow path resistance member 45 at a position on the side of the closing wall portion 111 that is closer to the central PA in the extending direction LG of the gas introduction portion 25, it can also be provided at a position corresponding to the central PA, or at a position that is further away from the closing wall portion 111 than the central PA.

[0056] In addition to providing the flow resistance member 45 in the first portion 25U of the gas introduction section 25, it may also be provided in the second portion 25B of the gas introduction section 25. In this case, the shape of each part of the flow resistance member 45 should be determined such that the flow resistance of the first portion 25U is greater than the flow resistance of the second portion 25B.

[0057] • The flow resistance member 45 can be anything other than a labyrinth structure. For example, the flow resistance member 45 can be a perforated plate, a number of cylindrical bodies, or a sponge-like material.

[0058] The opening shape of the opening 44 may be such that the portion PB closer to the surge tank 21 is wider than the portion PU further away from the surge tank 21 in the extension direction LM of the main passage 22M. In addition, the opening shape of the opening 44 may be such that it extends with the same width from portion PU to portion PB.

[0059] The shape of the opening 44 is not limited to being a long elongated hole in the extension direction LM, but can be any shape. For example, the shape of the opening 44 can be a long elongated hole in the direction perpendicular to the extension direction LM, or it can be circular or square.

[0060] The opening 44 can be provided in the inner portion of the curved portion 32 in the direction of curvature of the peripheral wall of the air intake section 22, or in the portion of the peripheral wall of the air intake section 22 corresponding to the inlet 31. The portion of the peripheral wall of the air intake section 22 in which the opening 44 is provided can be changed as desired.

[0061] The intake manifold according to the above embodiment can also be applied to intake manifolds of the type in which the air intake section does not have a curved section and the entire air intake section extends in a straight line.

[0062] The upstream portion 41 of the gas introduction section 25 may be connected to the sub-passage 43S in such a manner that the EGR gas flows out in a direction that intersects the extension direction LS of the sub-passage 43S at an angle other than "90 degrees". With this configuration as well, the EGR gas flowing from the upstream portion 41 into the sub-passage 43S of the downstream portion 43 can be made to collide with the inner surface of the sub-passage 43S, thereby causing turbulence in the flow of EGR gas within the sub-passage 43S.

[0063] Furthermore, when the EGR gas is brought into contact with the inner surface of the sub-passage 43S, the closer the collision angle is to "90 degrees", the stronger the turbulence that can be generated inside the sub-passage 43S. The strongest turbulence can be generated inside the sub-passage 43S when the collision angle is set to "90 degrees". For this reason, in order to generate strong turbulence inside the sub-passage 43S, it is preferable to connect the upstream part 41 of the gas introduction section 25 to the sub-passage 43S in a manner that causes the EGR gas to flow out in a direction perpendicular to the extension direction LS of the sub-passage 43S.

[0064] Alternatively, the upstream portion 41 of the gas introduction section 25 may be connected to the upper end portion of the sub-passage 43S. • As a gas inlet, a system can be adopted to introduce combustion gases (so-called blow-by gases) that have leaked from the combustion chamber of the internal combustion engine into the crankcase into the air inlet. In this configuration, the blow-by gas corresponds to the introduced gas. Alternatively, a system can be adopted to introduce evaporated fuel (so-called purge gases) from the fuel tank of the internal combustion engine into the air inlet. In this configuration, the purge gas corresponds to the introduced gas.

[0065] The intake manifold according to the above embodiment can also be applied to an intake manifold having a gas inlet that is connected to a surge tank and introduces EGR gas into the surge tank. Furthermore, the intake manifold according to the above embodiment can also be applied to an intake manifold having a gas inlet that is connected to a branch pipe and introduces EGR gas into the branch pipe.

[0066] <Note> The above embodiment includes the configuration described in the following appendix. [Note 1] An intake manifold comprising a surge tank, an air inlet connected to the surge tank for introducing air into the interior of the surge tank, and a manifold body having a plurality of branch pipes each individually connected to the surge tank, and a gas inlet connected to the manifold body for introducing an introduction gas other than air into the interior of the manifold body, wherein the gas inlet has a structure in which a first divided body and a second divided body, which are divided along the extending direction of the gas inlet, are integrally joined, and the inner surface of the first divided body at the position corresponding to the communication portion between the gas inlet and the manifold body has a shape that blocks a part of the gas inlet. An intake manifold is provided in which a blocking wall portion is provided, and the portion of the gas introduction section that is blocked by the blocking wall portion is such that a gap is formed between the protruding end of the blocking wall portion and the inner surface of the second divided body, and the protruding end of the blocking wall portion and the inner surface of the second divided body are arranged opposite each other, and when viewed from the extension direction, the portion of the gas introduction section on the side where the gap is formed is designated as the first portion, and the portion of the gas introduction section on the side where the gap is not formed is designated as the second portion, a flow resistance member is provided inside the gas introduction section that has a shape that makes the flow resistance of the first portion greater than the flow resistance of the second portion.

[0067] [Note 2] The intake manifold as described in [Note 1], wherein the flow resistance member has a plate-shaped first projection protruding from the inner surface of the first divided body and a plate-shaped second projection protruding from the inner surface of the second divided body, and the first projection and the second projection are arranged alternately in the extending direction to form a labyrinth structure.

[0068] [Note 3] The intake manifold according to [Note 1] or [Note 2], wherein the flow resistance member is provided only in the first portion of the first portion and the second portion.

[0069] [Note 4] The intake manifold according to any one of [Note 1] to [Note 3], wherein the flow path resistance member is provided at a position on the side of the communication portion rather than the center in the extending direction of the gas introduction portion. [Explanation of Symbols]

[0070] 10…Intake Manifold 11…First component 111...Closing wall part 112...First Pier 12...Second component 121...Second Pier 13…Third component 21... Surge tank 21R…Rear wall 22...Air intake 221…Fixed part 22M…Main passage 22R…Rear wall 23... Branch pipe 231...Proximal end 232...Tip 24 Mounting flange 25...Gas inlet 251…Fixed part 25U…1st part 25B…Second part 26... State detection unit 27…Pressure sensor 28, 29… Through holes 281,291... Boss section 31…Entrance 32... Curved section 41…Upstream 43…Downstream part 431...lower end 43S…Sub-passage 44…Opening 45...Flow resistance member 50…Reinforcement ribs

Claims

1. An intake manifold comprising a surge tank, an air inlet connected to the surge tank for introducing air into the surge tank, a manifold body having a plurality of branch pipes each individually connected to the surge tank, and a gas inlet connected to the manifold body for introducing an introduction gas other than air into the manifold body, The gas introduction section is cylindrical and is constructed by integrally joining together a first divided section and a second divided section, which are separated along the extending direction of the gas introduction section. The first divided body constitutes a part of the peripheral wall of the gas introduction section, The second divided body constitutes another part of the peripheral wall of the gas introduction section, On the inner surface of the first divided body, at the position corresponding to the communication portion between the gas introduction portion and the manifold body, a blocking wall portion is provided that is shaped to block a part of the gas introduction portion. The portion of the gas introduction section that is blocked by the blocking wall has a structure in which the tip of the blocking wall and the inner surface of the second divided body are positioned opposite each other, such that a gap is formed between the tip of the blocking wall and the inner surface of the second divided body. When viewed from the aforementioned extending direction, if the portion of the gas introduction section on the side where the gap is formed is designated as the first portion, and the portion of the gas introduction section on the side where the gap is not formed is designated as the second portion, A flow path resistance member is provided inside the gas introduction section. The flow resistance member is positioned in the first portion but not in the second portion, and has a plate-shaped first projection protruding from the inner surface of the first divided body and a plate-shaped second projection protruding from the inner surface of the second divided body. The first projection and the second projection are arranged alternately in the extending direction, thereby forming a labyrinthine flow path in the first portion. Intake manifold.

2. The flow path resistance member is provided in the gas introduction section at a position closer to the communication portion than to the center in the extending direction. The intake manifold according to claim 1.

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