JP2002235619A - Intake device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To favorably improve suction air distribution performance to each cylinder of an internal combustion engine while securing necessary volume as a surge tank in an intake device for an internal combustion engine. SOLUTION: An intake manifold 2 is provided with the surge tank 23, and an independent intake passage 22 to introduce suction air to each cylinder of the internal combustion engine 1 from the tank 23. Each independent intake passage 22 has an opening opened at an angle-varied position from a counter wall 23a of the surge tank 23 in a roughly L-letter form to an intake introducing direction, and opened in parallel around a projection part of an intake introducing port 21b in the counter wall 23a. The intake introducing port 21b is opened toward a center part of the surge tank 23, and on a front part of the counter wall 23a as seen from the intake introducing port 21b, a distribution plate 25 to distribute suction air to each separate intake passage 22 is provided. The distribution plate 25 is formed by protruding an inner wall of the surge tank 23 to be provided with its tip apart from the inner wall of the surge tank 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake device for an internal combustion engine having a plurality of cylinders.

[0002]

2. Description of the Related Art Generally, air taken into an internal combustion engine is filtered by an air cleaner and then introduced into a surge tank. The surge tank is connected to a plurality of independent intake passages that separately communicate the tank and each cylinder of the internal combustion engine. Through each of the independent intake passages, the intake air in the surge tank is supplied to each of the internal combustion engine. It is distributed and supplied to the cylinders.

[0003] The above intake air flows into the surge tank with a flow. For this reason, the intake air is more likely to be sucked into the independent intake passage that opens near such a flow and the independent intake passage that opens upstream of the same flow. As a result, a difference occurs between the intake air amounts of the respective cylinders of the internal combustion engine. In particular, when the difference between the intake air amounts increases, the difference between the output torques of the respective cylinders also increases, which may lead to a decrease in the performance of the internal combustion engine.

[0004] Conventionally, as a technique for improving the performance of distributing intake air to each cylinder, an intake device for an internal combustion engine described in Japanese Patent Application Laid-Open No. H8-31476 has been known. In this intake device, each independent intake passage is connected to the surge tank so as to open in a horizontal line in the surge tank. Further, an intake introduction passage for introducing intake air into the surge tank is connected to the surge tank so as to open further laterally than the above-described openings. Further, the intake passage is connected to the surge tank such that the direction in which the intake air is introduced into the surge tank and the direction in which the independent intake passages inhale the intake air form an acute angle.

[0005] Conventionally, a technique for improving the distribution performance of intake air to each cylinder is disclosed in Japanese Patent Application Publication No. 97465 (published by the Japan Automobile Manufacturers Association, Intellectual Property Committee). Devices are also known. In this intake device, the intake passage is arranged at the center of the surge tank, and the inner wall of the tank is arranged at a position where the flow of intake air introduced into the tank through the intake passage is blocked.

[0006] In each of these intake devices, the intake air introduced into the surge tank collides with the inner wall of the tank once and is scattered, and then is distributed and supplied to each independent intake passage. That is, by causing turbulence in the flow of intake air in the surge tank, the influence of the flow of intake air on the amount of intake air of each cylinder described above is reduced, and the distribution performance is improved.

[0007]

As described above, according to the above-mentioned conventional intake devices for internal combustion engines, the distribution performance of intake air can be improved. However, these intake devices still leave room for improvement in the following points.

First, in the intake device for an internal combustion engine described in the above-mentioned Japanese Patent Application Laid-Open No. H08-31476, an intake introduction passage is provided in the surge tank further laterally than each of the independent intake passages that are opened in a horizontal line. Is open, the distance from the intake passage is greatly different for each independent intake passage. Therefore, in such an intake device, even if the introduced intake air is scattered in the surge tank, it is difficult to avoid a problem that the air is more likely to be sucked in the independent intake passage closer to the intake introduction passage. That is, the distribution performance is still insufficient.

On the other hand, the issue number 9 of the above-mentioned automobile technology casebook
In the intake device for an internal combustion engine described in No. 7465, since the intake introduction passage is opened at the center of the surge tank, the difference in the distance between the opening of each independent intake passage and the opening of the intake introduction passage is small. The defect caused by the difference is improved.
However, in this intake device, the distance between the opening of the intake passage and the inner wall of the tank must be set small in order to make the intake air introduced into the surge tank appropriately collide with the inner wall of the tank. However, in this case, the volume of the surge tank is limited, and it is difficult to secure a necessary volume as the surge tank.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has as its object to appropriately improve the performance of distributing intake air to each cylinder of an internal combustion engine while securing a necessary volume as a surge tank. It is an object of the present invention to provide an intake device for an internal combustion engine that can be operated.

[0011]

The means for achieving the above object and the effects thereof will be described below. First, the invention according to claim 1 includes a surge tank connected to an intake passage of an internal combustion engine, and an independent intake passage for introducing intake air from the surge tank to each of a plurality of cylinders of the internal combustion engine. Each independent intake passage changes its angle from the opposite wall of the intake port connected to the intake path of the surge tank with respect to the intake direction, and is arranged in parallel around the projection of the intake port on the opposite wall. An intake device of the internal combustion engine, the intake port of the surge tank is opened toward a substantially central portion of the surge tank, and a front portion of the opposite wall has the same opposite wall. The gist of the invention is to provide a distribution plate for distributing the air drawn into the surge tank to the respective independent intake passages led out in parallel while maintaining the communication of the air to the surge tank.

According to the above construction, the difference in the distance between the opening of each independent intake passage and the opening of the intake port in the surge tank is set as small as possible, and the intake air introduced into the tank is distributed by the distribution plate. Will be scattered in the tank. Moreover, since this distribution plate is provided so as to maintain communication between the intake port and the opposite wall,
Regarding the volume of the surge tank, this can be made constant without depending on the arrangement position of the distribution plate.
Therefore, it is possible to preferably improve the performance of distributing the intake air to each cylinder of the internal combustion engine while securing the necessary volume as the surge tank.

According to a second aspect of the present invention, in the intake system for an internal combustion engine according to the first aspect, the distribution plate is a single plate extending along the direction in which the independent intake passages are arranged. The gist is that a part of the inner wall is protruded.

According to the above configuration, the distribution plate can be disposed without a complicated configuration such as mounting a separately formed distribution plate on the inner wall of the surge tank and a complicated mounting procedure. become. In addition, the distribution plate itself,
Although it is a very simple structure formed in the shape of a sheet,
The above-mentioned distribution function can be suitably realized.

According to a third aspect of the present invention, in the intake device for an internal combustion engine according to the first or second aspect, the distribution plate has one end provided apart from an inner wall of the surge tank. The main point is to maintain the communication of air to the opposite wall of the intake port through a gap with the inner wall of the air inlet.

According to the above construction, a predetermined space between one end of the distribution plate and the inner wall of the surge tank ensures a necessary volume for the surge tank regardless of the disposition position of the distribution plate. Will be able to

According to a fourth aspect of the present invention, in the intake device for an internal combustion engine according to the first or second aspect, the distribution plate has one or more holes penetrating the front and back surfaces thereof.
The gist of the invention is to maintain the communication of air to the opposite wall of the intake port through a plurality of holes.

According to the above configuration, the required volume of the surge tank can be secured by the holes provided in the distribution plate in advance, regardless of the arrangement position of the distribution plate.

Further, the invention described in claim 5 provides the invention according to claims 1 to
5. In the intake device for an internal combustion engine according to any one of the above items 4, each of the independent intake passages has a funnel portion at a connection portion with the surge tank, which assists inflow of air sucked into the surge tank into the independent intake passages. The gist of the present invention is that the distribution plate is arranged such that an end of each of the independent intake passages on the connection portion side with the surge tank is located downstream of the funnel portion.

According to the above configuration, the funnel portion allows
The efficiency of inflow of intake air from inside the surge tank to each independent intake passage can be improved. In addition, since the distribution plate is disposed near the funnel in a position where the influence on the flow of the intake air is extremely small, the inflow efficiency does not decrease with the provision of the distribution plate.

The invention according to claim 6 is the invention according to claims 2 to
5. The intake device for an internal combustion engine according to claim 5, wherein the surge tank and each of the independent intake passages include a first divided body provided with an intake inlet of a surge tank, and the surge of each of the independent intake passages. A second divided body constituting an outer tube side portion as viewed from the tank; and a divided piece elastically deformed and assembled to the second divided body as opposed to the wall of the intake inlet in the surge tank and the respective divided pieces. A third divided body that forms an inner pipe side portion of the independent intake passage when viewed from the same surge tank, wherein the distribution plate is provided in the first divided body. And

According to the basic structure of the intake device, for example, a distribution plate can be provided in the third divided body. However, in this case, the distribution plate serves as a reinforcing material, which prevents the third divided body from being elastically deformed during assembly. In this regard, according to the above configuration,
By avoiding such a problem, even when the distribution plate is provided, the assemblability thereof can be maintained high.

Further, the invention according to claim 7 is the same as the invention according to claims 1 to 3.
6. The intake device for an internal combustion engine according to any one of the aspects 6, wherein the distribution plate includes a reinforcing rib on a back surface of a surface of the surge tank facing the intake inlet.

According to the above configuration, the rigidity of the distribution plate can be improved, and the vibration can be suitably reduced. According to an eighth aspect of the present invention, in the intake device for an internal combustion engine according to any one of the first to seventh aspects, the surge tank and each of the independent intake passages are made of resin including the distribution plate. This is the gist.

According to the above configuration, the weight of the apparatus itself can be reduced.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an intake device for an internal combustion engine according to the present invention will be described in detail.

In the present embodiment, a surge tank integrated intake manifold (integrally formed with a plurality of divided bodies integrally with an independent intake passage that separately communicates a surge tank with a plurality of cylinders of an internal combustion engine). Hereinafter, an “intake manifold”) is an application of the intake device for an internal combustion engine according to the present invention. The intake manifold of the present embodiment is assumed to be applied to an in-line four-cylinder internal combustion engine.

First, the structure of the intake manifold will be described with reference to FIGS. FIG. 1 shows a side structure of the intake manifold. As shown in FIG. 1, the intake manifold 2 of the internal combustion engine 1 is provided with an intake introduction passage 21 protruding from an outer wall thereof. An intake side flange 21a for communicating the intake passage with an intake passage (not shown) connected to, for example, an air cleaner or the like, is provided at the tip of the intake passage 21.
Is provided. At the tip of each independent intake passage 22 of the intake manifold 2, the respective independent intake passage 22 is provided.
An engine-side flange 22a is provided for connecting the cylinder to each cylinder of the internal combustion engine 1.

FIG. 2 shows a partial sectional structure of the intake manifold 2. As shown in FIG. 2, hollow portions such as a surge tank 23 having a predetermined volume and each of the independent intake passages 22 are formed inside the intake manifold 2.

The intake passage 21 is arranged such that the intake opening 21b is opened substantially toward the center of the surge tank 23. The intake passage and the surge tank 23 communicate with each other through the intake introduction passage 21.

In the surge tank 23, the intake port 21b of the tank 23 viewed from the intake port 21b.
At the front of the opposite wall 23a, an inner wall of the tank 23 is formed so as to protrude, and a distribution plate 25 is provided. The distribution plate 25 is provided such that its tip is separated from the inner wall of the surge tank 23. Thus, although the distribution plate 25 is provided in the surge tank 23, the volume itself does not change.

The independent intake passages 22 are formed such that their openings in the surge tank 23 are opened at positions where the angle is changed in a substantially rectangular shape with respect to the direction of intake through the intake inlet 21b. In addition, they are provided so as to be opened in parallel around the projected portion of the intake inlet 21b in the opposite wall 23a. Thereby, each independent intake passage 22
Is set as small as possible. The distribution plate 25 is formed in a single plate along the direction in which the independent intake passages 22 are arranged.

Further, the connection between each independent intake passage 22 and the surge tank 23, that is, the opening of each independent intake passage 22, gradually turns outward as the entire inner wall of the passage 22 approaches the opening end. A funnel portion 24 having a curved shape is formed. Furthermore, each independent intake passage 22
Starting from the funnel section 24, the surge tank 2
The engine-side flange 22a is provided at an end point of the engine-side flange 22a. The distribution plate 2
5 is such that the end of the independent intake passage 22 on the side of the connection with the surge tank 23 is located on the downstream side of the funnel part 24, in other words, the influence on the intake flow near the funnel part 24 is extremely small. It is located at the location.

The intake air is distributed and supplied to the independent intake passages 22 by the intake manifold 2 as described below. First, the intake air filtered by the air cleaner is supplied to the surge tank 2 through the intake passage 21.
3 is introduced. Then, the intake air introduced into the surge tank 23 collides with the distribution plate 25 once and is scattered in the tank 23, and is then distributed and supplied to each independent intake passage 22.

FIG. 3 shows an exploded structure of the intake manifold 2. As shown in FIG. 3, the intake manifold 2 is divided into four pieces 31-34. Each of the pieces 31 to 34 is made of a synthetic resin formed by injection molding or the like. Of these four pieces 31 to 34, the first and second pieces 31 and 32 are provided with the intake inlet 21 b of the surge tank 23, and the fourth piece 34 is connected to the same tank of each independent intake passage 22. The third piece 33 constitutes a divided piece of the fourth piece 34 as opposed to the wall 23a of the intake inlet 21b in the same tank 23 and the same tank of each independent intake passage 22 as viewed from the side 23. 23, it constitutes the inner tube side.

More specifically, first, the first piece 31 mainly constitutes the intake passage 21 (intake opening 21b) and the downstream portion of each independent intake passage 22. The first piece 31 is formed with a plurality of recesses that constitute one pipe side of the downstream portion of each of the independent intake passages 22.

On the other hand, the second piece 32 mainly forms the engine-side flange 22a, the downstream part of each independent intake passage 22, the wall of the surge tank 23, and the distribution plate 25. In the second piece 32, a plurality of concave portions constituting the other pipe side portion with respect to the downstream portion of each of the independent intake passages 22 are formed. Then, by combining this concave portion with the concave portion formed in the first piece 31, a downstream portion of each independent intake passage 22 is formed.

Further, the third piece 33 mainly constitutes the upstream portion of each independent intake passage 22, the wall portion of the surge tank 23 which is the opposite wall 23a of the intake port 21b, and the funnel portion 24. The third piece 33 is formed in a corrugated cross section so as to constitute an inner pipe side portion of the upstream portion of each independent intake passage 22 when viewed from the surge tank 23. The third piece has an independent intake passage 22 therein.
A flange 24a is formed at one end corresponding to the opening side of the funnel 24 so as to constitute one side of the funnel 24. Furthermore,
The third piece is provided with a plurality of engagement projections 33a.

The fourth piece 34 mainly constitutes the upstream portion of each of the independent intake passages 22, the wall portion of the surge tank 23, and the funnel portion 24. A part of the fourth piece 34 is formed in a wave shape in cross section so as to form an outer pipe side when viewed from the surge tank 23 with respect to an upstream portion of each of the independent intake passages 22. Further, a step 25b is formed in the fourth piece 34 so as to constitute the other side of the funnel 24. And this 4th
By assembling the third piece 33 to the piece 34, the upstream portion of each of the independent intake passages 22 is formed by a portion formed into a corrugated cross section, and the funnel portion 24 is formed by the flange portion 24a and the step portion 25b. Each is formed. The fourth piece is provided with a plurality of engagement holes 34a formed at positions and shapes corresponding to the engagement protrusions 33a provided on the third piece 33, respectively.

Then, these four pieces 31 to 34
Are joined to each other by vibration welding or fixing by engagement, etc.
By being integrated, the intake manifold 2 is formed. In the present embodiment, intake manifold 2 is assembled as follows.

That is, first, each of the independent intake passages 2
The first piece 31 and the second piece 32 are integrally joined by vibration welding so as to form a downstream portion 2 ("Ia" in FIG. 3).

In addition, the third piece 33 and the fourth piece 34 are connected to the engaging projections 33a and the engaging holes 33 so as to mainly form the upstream portion of each of the independent intake passages 22 and the funnel portion 24. It is assembled together through engagement with 34a ("Ib" in FIG. 3). In this assembly, the third piece 33 is assembled to the fourth piece 34 while elastically deforming the third piece 33 so that the engagement protrusion 33a and the engagement hole 34a are engaged with each other.

Thereafter, in order to form the surge tank 23, the joined or assembled first and second pieces 31, 32 and third and fourth pieces 33, 34 are further welded together by vibration welding. (Fig. 3
"II" inside). Thus, the intake manifold 2 is integrally formed.

FIG. 4 shows the measurement results of the ratio of intake variation between the individual intake passages with respect to the engine speed of the intake manifold. In FIG. 4, a solid line indicates the intake manifold 2 of the above-described embodiment, and a dashed line indicates the distribution plate 25 described in the intake manifold 2.
, The relationship between the intake air variation ratio between the independent intake passages and the engine speed is shown.

As is apparent from FIG. 4, in the intake manifold 2 of the above-described embodiment, as compared with the intake manifold 2 in which the distribution plate 25 is omitted, the intake variation ratio can be kept small over the entire engine speed. Become.
That is, by providing the distribution plate 25 described above,
The performance of distributing intake air to each cylinder of the internal combustion engine 1 is improved.

As described above, according to the present embodiment, the following effects can be obtained. (1) Each independent intake passage 22 in the surge tank 23
By setting the difference in the distance between the opening and the opening of the air inlet 21b as small as possible, and by allowing the intake air introduced into the tank 23 to be scattered into the tank 23 by the distribution plate 25, The performance of distributing intake air to each cylinder of the internal combustion engine can be suitably improved. In addition, the distribution plate 25 does not completely partition the inside of the tank 23, that is, the tip is separated from the inner wall of the tank 23, and the communication between the intake port 21b and the wall 23a is maintained. As a result, it is easy to secure a necessary volume as a surge tank.

(2) The distribution plate 25 is provided such that the inner wall of the tank 23 projects. Therefore, the distribution plate 25 can be disposed without a complicated configuration such as mounting a separately formed distribution plate on the inner wall of the surge tank and a complicated mounting procedure.
Further, since the distribution plate 25 is formed in a single plate shape along the arrangement direction of the independent intake passages 22, the distribution performance of the intake air can be improved with a very simple structure. .

(3) A funnel 24 is formed at the opening of each independent intake passage 22. Therefore, the funnel portion 24 can improve the efficiency of inflow of the intake air from the surge tank 23 to each of the independent intake passages 22. Moreover, the position near the funnel portion 24 where the influence on the flow of the intake air is extremely small,
That is, since the distribution plate 25 is disposed downstream of the funnel portion 24, the inflow efficiency does not decrease with the provision of the distribution plate 25.

(4) The distribution plate 25 itself may be provided on the third piece 33 side, but the distribution plate 25 itself is provided on the second piece 32 side, so that the third piece 33 is provided. It is easy to assemble the fourth piece 34 with the elastic deformation.

(5) The intake manifold 2 is divided into four pieces 31 to 34, and each of the pieces 31 to 34 including the distribution plate 25 is made of synthetic resin. Therefore, it is possible to easily reduce the weight of the intake manifold.

The above embodiment may be modified and implemented as follows. In the intake manifold 2 of the above-described embodiment, the reinforcing rib 26 may be formed on the rear surface of the distribution plate 25 facing the intake port 21b. According to such a configuration, the rigidity of the distribution plate 25 can be improved, and its vibration can be suitably reduced.

In the above embodiment, the surge tank 23
In order to secure the required volume, a gap is set between the tip of the distribution plate 25 and the inner wall of the surge tank 23. Alternatively, the distribution plate may be provided with one or more holes penetrating the front and back. Even with such a configuration, it is possible to secure a required volume as a surge tank without depending on the arrangement position of the distribution plate by the holes.

In the above embodiment, each independent intake passage 2
Although the funnel portion 24 is formed in the opening 2,
If the intake air flows smoothly into the independent intake passages 22, it may be omitted.

In the above embodiment, the surge tank 23
The opening of each independent intake passage 22 in the inside is
Although the angle is changed in a substantially rectangular shape with respect to the direction of intake air through 1b, the configuration is not limited to this. The point is that each independent intake passage 22 changes its angle from the opposite wall 23a of the intake inlet 21b of the surge tank 23 with respect to the intake introduction direction, and is parallel to the projection of the intake inlet 21b on the opposite wall 23a. Any configuration may be used as long as the configuration is derived.

In the above embodiment, the third piece 33 and the fourth piece 34 are integrally assembled through the engagement between the engagement projection 33a and the engagement hole 34a. Alternatively, the third piece 33 and the fourth piece 34 may be joined to each other by fixing by vibration welding or the like. Even with such a configuration, the effects described in the above (1) to (3) and (5) can be obtained.

In the above embodiment, the distribution plate 25 is
Although it is provided so as to protrude from the piece 32, for example, as shown in FIG. 5, a cross-sectional structure corresponding to FIG. 2 of the intake manifold 4 as a modified example thereof corresponds to the distribution plate 25. The distribution plate 45 may be provided so as to protrude from the third piece 43. Even with such a configuration, the effects described in the above (1) to (3) and (5) can be obtained. In the intake manifold 4 illustrated in FIG. 5, the second piece 42 corresponds to the second piece 32 of the intake manifold 2 of the above embodiment, and the third piece 43
Corresponds to the third piece 33 of the intake manifold 2 of the embodiment.

As shown in FIG. 6, the distribution plate 25 from the second and third pieces 52 and 53 shows a cross-sectional structure corresponding to FIG. The distribution plates 55a and 55b may be formed so as to protrude, and the distal ends of the distribution plates 55a and 55b may be joined to each other at the time of assembly. By the way, in this case, the surge tank 23 is provided by the through hole 55c provided as described above.
Required volume is secured. According to such a configuration, the required rigidity can be easily secured without necessarily providing the above-described reinforcing ribs. Note that FIG.
In the intake manifold 5 illustrated in FIG.
The piece 52 corresponds to the second piece 32 of the intake manifold 2 of the embodiment, and the third piece 53 corresponds to the third piece 33 of the intake manifold 2 of the embodiment.

The provision of the distribution plates in the above-described manner has the effect of improving the performance of distributing the intake air to the respective cylinders of the internal combustion engine, and the arrangement is performed integrally from the inner wall of the surge tank. It is not limited to the one that is formed to protrude from the surface, and is arbitrary. In addition, the material including the distribution plate is not limited to the resin, but is arbitrary.

In the above embodiment, the intake device for an internal combustion engine according to the present invention is applied to an intake device for distributing and supplying intake air to each cylinder of an in-line four-cylinder internal combustion engine, but is not limited to this. Absent. The point is that the intake device for an internal combustion engine according to the present invention can be applied to any intake device that distributes and supplies intake air to each cylinder of an internal combustion engine having a plurality of cylinders.

[Brief description of the drawings]

FIG. 1 is a side view showing a side structure of an embodiment of an intake device for an internal combustion engine according to the present invention.

FIG. 2 is a cross-sectional view showing a partial cross-sectional structure of the intake device of the embodiment.

FIG. 3 is an exploded perspective view showing an exploded structure of the intake device of the embodiment.

FIG. 4 is a graph showing a relationship between a variation ratio of intake air between respective independent intake passages and an engine rotation speed.

FIG. 5 is a sectional view showing a partial sectional structure of a modification of the embodiment.

FIG. 6 is a sectional view showing a partial cross-sectional structure of another modification of the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Intake manifold, 21 ... Intake introduction passage, 21a ... Intake side flange, 21b ... Intake introduction port, 22 ... Independent intake passage, 22a ... Engine side flange,
Reference numeral 23: surge tank, 23a: opposite wall, 24: funnel portion, flange portion: 24a, step portion: 24b, 25, 4
5, 55a, 55b ... distribution plate, 26 ... reinforcing ribs, 31 ...
1st piece, 32, 52 ... 2nd piece, 33, 43, 5
Reference numeral 3 denotes a third piece, 33a denotes an engagement protrusion, 34 denotes a fourth piece, 34a denotes an engagement hole, and 55c denotes a through hole.

Claims (8)

[Claims] 1. A surge tank connected to an intake passage of an internal combustion engine, and independent intake passages for separately introducing intake air from the surge tank to a plurality of cylinders of the internal combustion engine. An internal combustion which is derived from an opposite wall of an intake inlet connected to the intake passage of the surge tank at an angle with respect to an intake introduction direction and is led in parallel around a projection of the intake inlet on the opposite wall. An intake device for an engine, wherein the intake opening of the surge tank is opened toward a substantially central portion of the surge tank, and a front portion of the opposite wall is provided for communicating air to the opposite wall. An intake device for an internal combustion engine, comprising: a distribution plate that distributes air taken into a surge tank to the independent intake passages that are led out in parallel while maintaining the distribution plate. 2. The intake system for an internal combustion engine according to claim 1, wherein the distribution plate is formed as a single plate along the direction in which the respective independent intake passages are arranged, and a portion of an inner wall of the surge tank protrudes. 3. The distribution plate has one end spaced apart from the inner wall of the surge tank, and maintains air communication with the opposite wall of the intake port through a gap with the inner wall of the surge tank. The intake device for an internal combustion engine according to claim 1 or 2, wherein: 4. The distribution plate has one or more holes penetrating the front and back, and maintains air communication with the opposite wall of the intake port through the one or more holes. 3. The intake device for an internal combustion engine according to 1 or 2. 5. Each of the independent intake passages is provided with a funnel portion at a connection portion with the surge tank to assist inflow of air sucked into the surge tank into the independent intake passages. The intake device for an internal combustion engine according to any one of claims 1 to 4, wherein an end of each of the independent intake passages on a connection portion side with the surge tank is located downstream of the funnel portion. . 6. The surge tank and each of the independent intake passages each include a first divided body provided with an intake inlet of the surge tank, and a pipe side portion of each of the independent intake passages which is located outside of the surge tank. And a divided piece that is elastically deformed and assembled to the second divided body as viewed from the opposite wall of the intake port in the surge tank and the same surge tank in each of the independent intake passages. And a third divided body that forms an inner tube side portion, wherein the distribution plate is provided in the first divided body.
The intake device for an internal combustion engine according to any one of claims 1 to 5. 7. The intake device for an internal combustion engine according to claim 1, wherein the distribution plate includes a reinforcing rib on a back surface of a surface of the surge tank facing the intake inlet. 8. The intake system for an internal combustion engine according to claim 1, wherein said surge tank and each of said independent intake passages are made of resin including said distribution plate.