JP7206984B2 - Inlet pipe and intake system parts - Google Patents

Description

The present invention relates to inlet pipes and intake system parts.

An intake system of an internal combustion engine includes an intake system component having a housing having an expansion chamber with a defined volume therein, and an inlet pipe having a pipe body whose end is connected to the housing of the intake system component. is provided. During operation of the internal combustion engine, air is introduced from the pipe body of the inlet pipe into the expansion chamber in the housing of the intake system component. Examples of the intake system parts include an air cleaner for removing foreign matters from the air taken into the internal combustion engine.

When air is introduced from the inlet pipe (pipe body) into the expansion chamber of the intake system component, the flow path of the air suddenly expands from the inlet pipe to the expansion chamber. Vortices are likely to occur in the air flow immediately after the In order to suppress the increase in pressure loss when the air passes through the expansion chamber due to the generation of such a vortex, in Patent Document 1, a widened portion is formed at the end of the main body of the inlet pipe. The widening portion is located in the expansion chamber of the intake system component and widens toward the end of the end portion. By rectifying the flow of air introduced from the inlet pipe into the expansion chamber of the intake system component at the expanded portion, the air flow immediately after being introduced into the expansion chamber is restrained from being swirled. ing.

In addition, if the expansion along the flow of air in the expanded portion is rapid, the air flowing along the inner wall surface of the expanded portion will separate from the inner wall surface, and the inlet pipe will flow into the intake system. It becomes difficult to rectify the flow of air introduced into the expansion chamber of the component by the expansion portion. For this reason, in Patent Document 1, by forming projections on the inner wall surface of the expanded portion, an air vortex is generated in a portion of the inner wall surface on the downstream side of the projections. In this case, the air flow along the inner wall surface is attracted to the inner wall surface side by the air vortex generated at the portion downstream of the protrusion on the inner wall surface of the expansion portion, so that the air flow along the inner wall surface Separation of flowing air from the inner wall surface is suppressed.

Japanese Patent No. 6065809

As shown in Patent Document 1, by forming projections on the inner wall surface of the expanded portion, separation of the air flowing along the inner wall surface from the inner wall surface can be suppressed. An increase in pressure loss when the air passes through the expansion chamber is unavoidable due to the occurrence of air vortices in the portion downstream of the projection on the inner wall surface of the expanded portion. Therefore, there is room for further improvement in terms of suppressing an increase in pressure loss when air passes through the expansion chamber.

SUMMARY OF THE INVENTION An object of the present invention is to provide an inlet pipe and an intake system part that can suppress an increase in pressure loss when air passes through an expansion chamber in a housing.

Means for solving the above problems and their effects will be described below.
An inlet pipe for solving the above-mentioned problems includes a pipe body having an end connected to a housing provided in an intake system of an internal combustion engine and having an expansion chamber with a predetermined volume therein. to introduce air into the expansion chamber. The end portion of the pipe body is formed with a widened portion located in the expansion chamber in the housing and widening toward the end of the end portion. Further, at a position closer to the center line of the pipe body than the expanded portion is an inner cylindrical portion having an outer wall surface facing the inner wall surface of the expanded portion and extending in the direction of the center line of the pipe body. is provided.

According to the above configuration, when air is introduced from the inlet pipe (pipe main body) into the expansion chamber in the housing, the air flows between the inner wall surface of the expanded portion and the outer wall surface of the inner cylindrical portion and the inner cylinder. It will pass through the inside of the part. The rectification of the flow of air introduced from the inlet pipe into the expansion chamber is performed by the expanded portion and the inner cylindrical portion of the pipe body. Here, if the air flowing along the inner wall surface of the expanded portion were separated from the inner wall surface, it would be difficult for the expanded portion to rectify the flow of the air. However, the separation of the air flowing along the inner wall surface of the expanded portion from the inner wall surface is suppressed by the outer wall surface of the inner cylindrical portion, so that it is not difficult to rectify the air by the expanded portion. . On the other hand, if the air flowing along the inner wall surface of the inner cylindrical portion among the air passing inside the inner cylindrical portion separates from the inner wall surface, it becomes difficult for the inner cylindrical portion to rectify the flow of the air. Become. However, the air introduced into the expansion chamber through the inner side of the inner cylindrical portion has a Coanda effect based on the flow of air passing between the inner wall surface of the expanding portion and the outer wall surface of the inner cylindrical portion and flowing into the expansion chamber. Therefore, it is drawn toward the air flow, in other words, toward the inner wall surface of the inner cylindrical portion. Therefore, the flow of air flowing along the inner wall surface of the inner cylindrical portion does not separate from the inner wall surface of the inner cylindrical portion, making it difficult for the inner cylindrical portion to rectify the air flow. As described above, since the rectification of the air flow by the expanding portion and the inner cylindrical portion can be realized without using the vortex of the air, the vortex increases the pressure loss when the air passes through the expansion chamber. to do is restrained.

An intake system component that solves the above problems includes a housing that is provided in an intake system of an internal combustion engine and has an expansion chamber with a predetermined volume therein, and air flows into the expansion chamber from an inlet pipe that is connected to the housing. be introduced. A portion of the housing to which the inlet pipe is connected is formed with an expanded portion that expands toward the expansion chamber. Further, an inner cylindrical portion has an outer wall surface facing the inner wall surface of the expanded portion at a position closer to the center line of the inlet pipe than the expanded portion, and extends in the center line direction of the inlet pipe. is provided.

According to the above configuration, when air is introduced from the inlet pipe into the expansion chamber of the intake system component, the air is introduced between the inner wall surface of the expanded portion and the outer wall surface of the inner cylindrical portion and the inner side of the inner cylindrical portion. pass through. The rectification of the flow of air introduced from the inlet pipe into the expansion chamber is performed by the expanded portion and the inner cylindrical portion of the housing. Here, if the air flowing along the inner wall surface of the expanded portion were separated from the inner wall surface, it would be difficult for the expanded portion to rectify the flow of the air. However, the separation of the air flowing along the inner wall surface of the expanded portion from the inner wall surface is suppressed by the outer wall surface of the inner cylindrical portion, so that it is not difficult to rectify the air by the expanded portion. . On the other hand, if the air flowing along the inner wall surface of the inner cylindrical portion among the air passing inside the inner cylindrical portion separates from the inner wall surface, it becomes difficult for the inner cylindrical portion to rectify the flow of the air. . However, the air introduced into the expansion chamber through the inner side of the inner cylindrical portion has a Coanda effect based on the flow of air passing between the inner wall surface of the expanding portion and the outer wall surface of the inner cylindrical portion and flowing into the expansion chamber. Therefore, it is drawn toward the air flow, in other words, toward the inner wall surface of the inner cylindrical portion. Therefore, the flow of air flowing along the inner wall surface of the inner cylindrical portion does not separate from the inner wall surface of the inner cylindrical portion, making it difficult for the inner cylindrical portion to rectify the air flow. As described above, since the rectification of the air flow by the expanding portion and the inner cylindrical portion can be realized without using the vortex of the air, the vortex increases the pressure loss when the air passes through the expansion chamber. to do is restrained.

According to the present invention, it is possible to suppress an increase in pressure loss when air passes through the expansion chamber in the housing.

1 is a schematic diagram showing an air cleaner provided in an intake system of an internal combustion engine and its peripheral structure; 4(a) and 4(b) are a front view of the inlet pipe as seen from the expanded portion and the inner cylindrical portion, and a perspective view of the inlet pipe as seen obliquely from above; FIG. (a) and (b) are cross-sectional views showing the inlet pipe viewed from the direction of arrow AA in FIG. Enlarged sectional view showing a part. FIG. 4 is an enlarged cross-sectional view showing a portion of the air cleaner housing connected to the pipe body of the inlet pipe;

[First Embodiment]
An embodiment of the inlet pipe will be described below with reference to FIGS. 1 to 3. FIG.
FIG. 1 schematically shows an air cleaner 1 provided in an intake system of an internal combustion engine and its peripheral structure. The inside of the housing 2 of the air cleaner 1 is partitioned into an introduction space 4 and a discharge space 5 by a filter 3 . The air cleaner 1 having the housing 2 having the introduction space 4 and the discharge space 5 therein functions as an intake system component having a housing having an expansion chamber with a predetermined volume.

In the housing 2 , an inlet pipe 6 is connected to a portion corresponding to the introduction space 4 and an outlet pipe 7 is connected to a portion corresponding to the discharge space 5 . During operation of the internal combustion engine, air is introduced from the inlet pipe 6 into the introduction space 4 in the housing 2, and the air passes through the filter 3 and flows to the discharge space 5 side. foreign matter is removed by the filter 3. After that, the air that has flowed into the lead-out space 5 is led out of the housing 2 (air cleaner 1 ) through the outlet pipe 7 .

Next, the inlet pipe 6 will be described in detail.
The inlet pipe 6 has a pipe body 8 whose end (right end in FIG. 1) is connected to the housing 2 of the air cleaner 1 . While connected to the housing 2, the end of the pipe body 8 is inserted into the introduction space 4 within the housing 2, in other words, the portion upstream of the filter 3 within the housing 2. .

A portion of the end of the pipe body 8 located in the introduction space 4 is formed with a cylindrical expanded portion 9 that expands toward the end of the end (the right end in FIG. 1). Further, a portion located in the introduction space 4 at the end of the pipe body 8 and at a position closer to the center line of the pipe body 8 than the expanded portion 9 faces the inner wall surface 9a of the expanded portion 9. A cylindrical inner tube portion 10 is provided having an outer wall surface 10a that is aligned with the outer wall surface 10a. The inner cylindrical portion 10 extends in the direction of the center line of the pipe body 8, similarly to the expanding portion 9. As shown in FIG.

2(a) and 2(b) respectively show the inlet pipe 6 viewed from the widening portion 9 and the inner cylindrical portion 10 side, and the inlet pipe 6 viewed obliquely from above. As can be seen from these drawings, a plurality of (three in this example) support pieces 11 are provided between the expanded portion 9 and the inner cylindrical portion 10 in the circumferential direction of the expanded portion 9 and the inner cylindrical portion 10 . provided at intervals. The support pieces 11 are formed integrally with the expanding portion 9 and the inner cylindrical portion 10 . The inner tubular portion 10 is supported by the expanded portion 9 by means of support pieces 11 .

3(a) and 3(b) respectively show the inlet pipe 6 viewed from the direction of arrow AA in FIG. It shows the enlarged state of the part surrounded by . As can be seen from FIGS. 3(a) and 3(b), the inner wall surface 9a of the expansion portion 9 and the outer wall surface 10a of the inner cylinder portion 10 diverge toward the downstream side (right side in FIG. 3(b)). They are curved with the same curvature as each other so as to expand. Therefore, the distance between the inner wall surface 9a and the outer wall surface 10a is constant in the centerline direction of the inlet pipe 6 (pipe body 8).

Next, the action of the inlet pipe 6 will be described.
When air is introduced into the introduction space 4 in the housing 2 from the inlet pipe 6 (pipe body 8), the air flows through the inner wall surface 9a of the expanded portion 9 and the inner cylinder as indicated by the arrows in FIG. 3(a). It comes to pass between the outer wall surface 10 a of the portion 10 and the inner side of the inner cylindrical portion 10 . The rectification of the flow of air introduced from the inlet pipe 6 into the introduction space 4 is performed by the expanded portion 9 and the inner cylindrical portion 10 of the pipe body 8 .

Here, if the air flowing along the inner wall surface 9a of the expanded portion 9 separates from the inner wall surface 9a, it becomes difficult for the expanded portion 9 to rectify the air flow. However, since the separation of the air flowing along the inner wall surface 9a of the expanding portion 9 from the inner wall surface 9a is suppressed by the outer wall surface 10a of the inner cylinder portion 10, the air is rectified by the expanding portion 9. It won't be difficult.

On the other hand, if the air flowing along the inner wall surface 10b of the inner cylindrical portion 10 among the air passing inside the inner cylindrical portion 10 is separated from the inner wall surface 10b as indicated by an arrow Y1 in FIG. Then, it becomes difficult for the inner cylindrical portion 10 to rectify the air flow. However, the air introduced into the introduction space 4 through the inside of the inner cylindrical portion 10 is separated from the inner wall surface 9a of the expanded portion 9 and the outer wall surface 10a of the inner cylindrical portion 10 as indicated by the arrow Y2 in FIG. 3(b). Due to the Coanda effect based on the flow of air passing between and into the introduction space 4 , the air is attracted toward the flow of air, in other words, toward the inner wall surface 10 b of the inner cylindrical portion 10 . As a result, the flow of the air drawn toward the inner wall surface 10b follows the inner wall surface 10b as indicated by the arrow Y3 in FIG. 3(b). As a result, the air flow along the inner wall surface 10b of the inner cylindrical portion 10 separates from the inner wall surface 10b as indicated by the arrow Y1 in FIG. Commutation is not difficult.

In this way, the rectification of the air flow by the expanding portion 9 and the inner cylindrical portion 10 can be realized without using the vortex of the air. Growth is suppressed.

According to this embodiment detailed above, the following effects can be obtained.
(1) During operation of the internal combustion engine, when air is introduced from the inlet pipe 6 into the housing 2 of the air cleaner 1, the air passes through the housing 2, but the increase in pressure loss at that time should be avoided. can be suppressed.

(2) The air introduced from the inlet pipe 6 into the introduction space 4 in the housing 2 of the air cleaner 1 is the air before dust and other foreign matter is removed by the filter 3 of the air cleaner 1 . For this reason, if the inner wall surface 9a of the expanding portion 9 is provided with projections, etc., as in Patent Document 1 described in the Background Art column, foreign matter such as dust in the air will be generated around the projections. deposits on However, since the inner wall surface 9a of the expanded portion 9 of the inlet pipe 6 is not formed with the above-described projections, foreign substances such as dust in the air are prevented from accumulating around the projections.

[Second embodiment]
An embodiment of the air cleaner will be described below with reference to FIG.
In this embodiment, the housing 2 of the air cleaner 1 is provided with the widening portion and the inner cylindrical portion instead of the inlet pipe 6 having the widening portion 9 and the inner cylindrical portion 10 as in the first embodiment.

FIG. 4 shows an enlarged view of a portion of the housing 2 of the air cleaner 1 where the inlet pipe 6 is connected to the pipe body 8 . A portion of the housing 2 to which the inlet pipe 6 (pipe body 8) is connected is formed with a cylindrical expanded portion 21 that expands toward the introduction space 4 side (right side in FIG. 4) in the housing 2. there is

In the expanded portion 21, the outer diameter of the inlet pipe 6 side end (the left end in FIG. 4) is substantially the same as the inner diameter of the pipe body 8 side of the housing 2 side (the right end in FIG. 4). there is Therefore, the end portion of the pipe body 8 on the housing 2 side can be fitted into the end portion of the expanded portion 21 on the inlet pipe 6 side, and the inlet pipe 6 is connected to the housing 2 through such fitting. An end portion (right end portion in FIG. 1) of the expanded portion 21 on the housing 2 side is formed integrally with the housing 2 so as to be connected to the housing 2 .

At a position closer to the center line of the inlet pipe 6 than the expanding portion 21 is an outer wall surface 22a facing the inner wall surface 21a of the expanding portion 21, and extending in the center line direction of the inlet pipe 6. An extending inner tubular portion 22 is provided. Further, the inner cylindrical portion 22 is provided between the outer wall surface 22a and the inner wall surface 21a via a plurality of support pieces 23 (only one is shown in this example) formed integrally with the outer wall surface 22a and the inner wall surface 21a. 21. In addition, the plurality of support pieces 23 are provided at predetermined intervals in the circumferential direction of the expanding portion 21 and the inner cylindrical portion 22 .

The inner wall surface 21a of the expanded portion 21 and the outer wall surface 22a of the inner cylindrical portion 22 are curved with the same curvature so that they expand toward the downstream side (right side in FIG. 4). Therefore, the distance between the inner wall surface 9a and the outer wall surface 10a is constant in the centerline direction of the inlet pipe 6 (pipe body 8).

Also in this embodiment, the same effects as (1) and (2) of the first embodiment can be obtained.
[Other embodiments]
It should be noted that each of the above-described embodiments can be modified, for example, as follows.

- The distance between the inner wall surface 9a of the expanded portion 9 and the outer wall surface 10a of the inner cylindrical portion 10 in the first embodiment does not necessarily have to be constant in the centerline direction of the inlet pipe 6 (pipe body 8).

- A notch portion may be formed in a part of the circumferential direction of the expanded portion 9 and the inner cylindrical portion 10 in the first embodiment.
- You may change the number of the support pieces 11 in 1st Embodiment suitably.

- The distance between the inner wall surface 21a of the expanded portion 21 and the outer wall surface 22a of the inner cylindrical portion 22 in the second embodiment does not necessarily have to be constant in the centerline direction of the inlet pipe 6 (pipe body 8).

- A notch part may be formed in a part of the circumferential direction of the expanding part 21 and the inner cylinder part 22 in 2nd Embodiment.
- You may change the number of the support pieces 23 in 2nd Embodiment suitably.

- Although the present invention is applied to the air cleaner 1 and the inlet pipe 6 connected thereto, the present invention may be applied to intake system parts other than the air cleaner 1 and inlet pipes connected thereto, such as surge tanks and inlet pipes connected thereto.

DESCRIPTION OF SYMBOLS 1... Air cleaner 2... Housing 3... Filter 4... Introduction space 5... Lead-out space 6... Inlet pipe 7... Outlet pipe 8... Pipe main body 9... Expansion part 9a... Inner wall surface 10... Inner tubular portion 10a Outer wall surface 10b Inner wall surface 11 Support piece 21 Widening portion 21a Inner wall surface 22a Outer wall surface 22 Inner tubular portion 23 Support piece.

Claims (4)

A pipe body having an end portion connected to a housing provided in an intake system of an internal combustion engine and having an expansion chamber with a predetermined volume therein, air is introduced into the expansion chamber through the pipe body. in the inlet pipe,
The end portion of the pipe body is formed with an expanded portion located in the expansion chamber in the housing and expanding toward the end of the end portion,
An inner cylindrical portion having an outer wall surface facing the inner wall surface of the expanded portion at a position closer to the center line of the pipe body than the expanded portion, and extending in the center line direction of the pipe body. is provided ,
A space between the expanded portion and the inner cylindrical portion is always open.
An inlet pipe characterized by: The housing is an air cleaner housing provided in an intake system of an internal combustion engine,
2. The inlet pipe according to claim 1, wherein the end of the pipe body is inserted into a portion upstream of the filter in the housing of the air cleaner. An intake system component that is provided in an intake system of an internal combustion engine and has a housing that has an expansion chamber with a predetermined volume inside, and air is introduced into the expansion chamber from an inlet pipe connected to the housing,
A portion of the housing to which the inlet pipe is connected is formed with an expanding portion that expands toward the expansion chamber,
An inner tubular portion having an outer wall surface facing the inner wall surface of the expanded portion at a position closer to the center line of the inlet pipe than the expanded portion, and extending in the direction of the center line of the inlet pipe. is provided ,
A space between the expanded portion and the inner cylindrical portion is always open.
An intake system part characterized by: The housing is an air cleaner housing provided in an intake system of an internal combustion engine,
4. An intake system component according to claim 3, wherein said expanding portion and said inner cylindrical portion are provided in a portion of said housing on the upstream side of said filter.

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