JPH11141420A - Intake foreign sound reducing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the foreign sound from an intake manifold surge tank by arranging a net in a part of an intake passage cross section in the downstream and vicinity of a throttle valve, and arranging a plurality of current straightening plates extending in the direction parallel to the intake passage axial core in a part of the remaining part. SOLUTION: This intake foreign sound reducing structure comprises a net 1 provided in a part of an intake passage cross section and a plurality of current straightening plates 7 provided in at least a part of the part having no net 1 of the intake passage cross section. The net 1 is provided in the part to which the flow carried through the clearance between the part brought down on the upstream side of a throttle valve 2 in opening and a passage wall 8 is collided, so that the turbulence of the flow can be reduced and the generation of the vibration of the passage wall 8 and generation of the foreign sound can be suppressed. Further by installing the current straightening plate 7, whereby the flow carried through the clearance between the part fallen on the downstream side in opening and the passage wall 8 is prevented from being dispersed in lateral direction when carried to the part of the current straightening plates 7, so that the turbulence of the flow is hardly caused.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for reducing abnormal noise in an intake air, for example, a structure for reducing abnormal noise generated from an integrated structure of an intake manifold and a surge tank of an automobile (hereinafter referred to as an intake manifold surge tank).

[0002]

2. Description of the Related Art When a throttle valve is suddenly opened in an automobile, high frequency noise is generated from a portion of an intake manifold surge tank. This abnormal noise occurs regardless of whether the intake manifold surge tank is made of resin or aluminum. Especially, a loud noise is generated in the intake manifold surge tank made of resin. Conventionally, a structure in which a wire mesh is disposed between the throttle valve and the engine combustion chamber has been proposed as a measure against backfire from the engine, although not a measure against abnormal noise (for example, Japanese Utility Model Laid-Open No. 57-107838).
issue).

[0003]

In recent years, the intake manifold surge tank has tended to be made of resin in order to reduce the weight and thereby improve the fuel efficiency. In particular, the noise of the intake manifold surge tank made of resin has become a problem. Have been doing. A structure in which a wire mesh is disposed between the throttle valve and the engine combustion chamber as a countermeasure against backfire is also effective in reducing abnormal noise, but has another problem of increasing passage resistance. An object of the present invention is to provide an abnormal noise reduction structure capable of reducing abnormal noise from an intake manifold surge tank. However, it is assumed that the ventilation resistance is not increased unacceptably.

[0004]

The present invention to achieve the above object is as follows. (1) A net is arranged on a part of the cross section of the intake passage downstream and near the throttle valve, and a plurality of rectifying plates extending in a direction parallel to the axis of the intake passage is arranged on at least a part of the remaining part. Abnormal noise reduction structure. (2) In the cross section of the intake passage, the net is arranged on a half section on the side where the throttle valve falls to the upstream side when the throttle valve is opened, and the plurality of rectifying plates are provided on at least a part of the remaining half section. The intake abnormal noise reduction structure according to (1), which is arranged. (3) The intake abnormal noise reduction structure according to (1) or (2), wherein the plurality of rectifying plates are arranged in parallel with each other. (4) The intake abnormal noise reduction structure according to (1) or (2), wherein the plurality of rectifying plates are radially arranged with respect to an axis of the intake passage.

[0005] Analysis of the flow of intake air when the throttle valve was opened in a state where a butterfly type throttle valve was disposed in a pipe having a circular cross section and no net was disposed, revealed the following. The flow passing through the side where the throttle valve falls to the upstream side has a greater influence on the turbulent flow formation than the flow passing through the side where the throttle valve falls to the downstream side. The flow passing through the side where the throttle valve falls to the upstream side concentrates toward the center in plan view, while the flow passing through the side where the throttle valve falls to the downstream side spreads out in plan view. The flow passing through the side where the throttle valve falls to the upstream side causes first turbulence when passing through the gap between the throttle valve and the pipe wall. The second flow collides with the flow, and then flows obliquely downward and collides with the flow that has passed the side on which the throttle valve falls to the downstream side, thereby generating a third turbulence. In the flow disturbance generating section, high-frequency pressure fluctuation occurs, which vibrates the passage wall and is radiated as abnormal noise.

In the above-described intake noise reduction structure (1) to (4), a net is disposed downstream and near the throttle valve to lower the level of the first turbulence and to reduce the flow concentrated toward the center. The second and third disturbances are eliminated by making it less likely to occur. This reduces abnormal noise generated in the intake manifold surge tank when the throttle valve is opened. In addition, the rectifying plate suppresses the flow of the flow passing between the throttle valve and the passage wall on the side corresponding to the upstream of the rectifying plate in the passage cross section to the left and right, and the point where the flow goes to the center of the passage is the downstream side. , It is less likely to collide with the flow passing between the throttle valve and the passage wall on the side corresponding to the upstream of the net in the passage cross section.
Is less likely to occur and noise is reduced accordingly. In the above (1) to (4), since the net is provided only in a part of the passage cross section, the resistance of the passage does not significantly increase, and both the suppression of the increase in the passage resistance and the suppression of the abnormal noise are satisfied. .

In the above (2), since the net is arranged on a half section on the side where the throttle valve falls to the upstream side when the throttle valve is opened, the first disturbance can be reduced most, and the noise reduction effect is great. It is. In the above (3), since the rectifier plates are arranged in parallel with each other, an excellent noise reduction effect is obtained in both the low frequency region and the high frequency region. In the above (4), since the rectifying plates are arranged radially, an excellent noise reduction effect is obtained in a relatively low frequency region.

[0008]

1 and 2 show a first embodiment of the present invention, FIG. 3 shows a second embodiment of the present invention, and FIG. 4 shows a noise reduction effect according to the present invention. Is shown. In the drawings, structural parts common to all embodiments of the present invention are denoted by the same reference numerals throughout all embodiments of the present invention.

A structure common to all embodiments of the present invention will be described with reference to FIGS. The abnormal noise reduction structure according to the embodiment of the present invention includes a throttle valve 2 disposed in an intake passage of an automobile engine, an intake manifold surge tank 3 downstream thereof, and a part of a cross section of the intake passage disposed immediately downstream of the throttle valve 2. And a plurality of rectifying plates 7 disposed immediately downstream of the throttle valve 2 and disposed at least in a portion of the cross section of the intake passage where the net is not disposed. The intake air passes through a gap between the throttle valve 2 and the passage wall 8, then passes through the net 1 and the rectifier plate 7, flows into the intake manifold surge tank 3, and further flows into the engine cylinder. The throttle valve 2 is arranged in a throttle body 4 usually made of metal. The throttle valve 2 is composed of a butterfly type valve, and is turned around a rotation axis to open and close a passage. When the throttle valve 2 opens,
One side (upper side in the illustrated example) of the axis of rotation of the throttle valve 2 falls toward the upstream side, and the other side (lower side in the illustrated example) falls toward the downstream side.

[0010] The intake manifold surge tank 3 comprises:
An intake manifold 5 and a surge tank 6 are provided. The intake manifold surge tank 3 is made of resin or metal, and is connected to the throttle body 4 with the net 1 interposed therebetween. When the intake manifold surge tank 3 is made of resin, the intake manifold section 5 and the surge tank 6 are integrally formed. When the intake manifold surge tank 3 is made of resin, the rectifying plate 7 may be formed integrally with the passage wall 8. However, intake manifold surge tank 3 may be made of metal (for example, aluminum).

An intake manifold surge tank 3;
A metal spacer may be interposed between the throttle body 4 and the metal. In that case, the net 1 is interposed between the throttle body 4 and the spacer. The net 1 is disposed at least in a portion of the throttle valve 2 where intake air flowing through a gap between the portion that falls to the upstream side when the valve is opened and the passage wall 8 hits, and the rectifying plate 7 is connected to the throttle valve 2. Among them, it is arranged at a portion where the intake air flowing through the gap between the portion that falls to the downstream side when the valve is opened and the passage wall 8 hits.

The operation of the above structure will be described. In the present invention,
Since the net 1 is provided in a part of the cross section of the intake passage and the rectifying plate 7 is provided in at least a part of the cross section of the intake passage where the net is not provided, FIG. 4 (when the intake surge tank is made of resin) As shown in the figure, when the net and the rectifying plate are not provided, the net 1 and the rectifying plate 7 are simply provided (the net 1 and the rectifying plate 7 are overlapped in the cross-sectional direction of the passage), and the noise is larger than that of A reduction effect is obtained. Also,
As shown in FIG. 4, the present invention provides a straightening plate 7 on a half section on the side where the throttle valve 2 falls to the upstream side when the throttle valve is opened, and a half section on the side where the throttle valve 2 falls on the downstream side when the throttle valve is opened. In the case where the net 1 is provided, the net 1 is provided on a half section on the side where the throttle valve 2 falls to the upstream side when the throttle valve is opened, and the straightening plate is provided on the half section on the side where the throttle valve 2 falls on the downstream side when the throttle valve is opened. 7 is provided, but in the case of, a greater noise reduction effect is obtained than in the case of.

The reason for the reduction of the abnormal noise will be described as follows. As a result of the flow analysis, the portion of the throttle valve 2 that falls to the upstream side when the valve is opened and the passage wall 8
It has been found that the flow flowing through the gap between and has a significant effect on the generation of abnormal noise. When neither the net 1 nor the rectifying plate 7 is provided (conventional), the flow flowing through the gap between the passage wall 8 and the portion of the throttle valve 2 that falls on the upstream side when the valve is opened is the first flow when passing through the throttle valve portion.
The turbulence is formed in the center of the pipe in a plan view, and the left and right flows are concentrated to form a second turbulence there. It collides with the flow flowing through the gap between the part that falls down to the side and the passage wall 8 to form a third turbulence. The turbulence of the flow causes a high-frequency pressure fluctuation, which causes the passage wall 8 to vibrate, generating abnormal noise. Particularly when the passage wall 8 is made of resin, the noise is large.

In the present invention, the provision of the net 1 reduces the level of disturbance in the portion downstream of the net 1 in the first disturbance. Further, downstream of the net 1, the flow velocity of the high flow velocity portion decreases due to the flow resistance of the net 1, and the flow concentrates on the left and right, and the portion of the throttle valve 2 that falls down on the downstream side when the valve opens and the passage wall 8. The flow and the collision flowing through the gap between them are alleviated, and the second and third disturbances are also reduced. The turbulence reducing effect of the net 1 is greatest when the net 1 is provided in a portion of the throttle valve 2 where the flow flowing through the gap between the portion that falls to the upstream side when the valve is opened and the passage wall 8 hits. Thus, by providing the net 1 at a portion of the throttle valve 2 where the flow flowing through the gap between the passage wall 8 and the portion that falls to the upstream side when the valve is opened hits the first, second, and third. Turbulence can be reduced, and vibration of the passage wall and generation of abnormal noise can be suppressed. Although the turbulence of the portion upstream of the net 1 remains as it is, the passage wall of the portion upstream of the net 1 is the throttle body itself and is made of metal, so that it does not easily vibrate and does not pose a problem in generating abnormal noise.

Further, in the present invention, the flow straightening plate 7 is provided, so that in the case of FIG. 4, the throttle valve 2 flows through the gap between the portion of the throttle valve 2 that falls down when the valve is opened and the passage wall 8. When the flow has flowed to the flow straightening plate 7 portion, the dispersion of the flow in the left and right direction is suppressed, and the left and right dispersed flow is suppressed from going upward along the pipe wall. The shift becomes difficult to collide with the flow descending from above, and the third disturbance is less likely to occur. Thereby, the abnormal noise is further reduced as compared with the case where only the net 1 is provided. A similar effect is obtained in the case of FIG. However, as shown in FIG.
Even if the rectifying plate 7 is provided on the same side, the third turbulence preventing effect by the collision prevention of the flow from above and below cannot be obtained, so that the noise reduction effect by the rectifying plate 7 cannot be obtained. Is not included.

Next, the structure and operation unique to each embodiment of the present invention will be described. In the first embodiment of the present invention, as shown in FIG. 2, a plurality of rectifying plates 7 are arranged in parallel with each other and in a direction orthogonal to the throttle valve rotation axis. The height of the current plate 7 is arbitrary, and as shown in FIG. 4, the end of the current plate may extend to the position of the diameter of the passage (the current plate heights are different from each other), or shown in FIG. As described above, the heights of the plurality of straightening plates 7 may be substantially constant. In the second embodiment of the present invention, as shown in FIG. 3, a plurality of rectifying plates 7 are arranged on a line extending radially from the passage axis. The height of the current plate 7 is arbitrary, and the height of the current plate 7 may be substantially constant as shown in FIG.

As for the operation of the first embodiment and the second embodiment of the present invention, as shown in FIG. 5, both of the embodiments have an excellent noise reduction effect.
z), the noise reduction effect of the first embodiment in which the rectifying plates are parallel to each other is about 2.4 dB larger than that of the second embodiment in which the rectifying plates are radial.

[0018]

According to the abnormal noise reduction structure of claims 1 to 4,
By arranging the net downstream and near the throttle valve, the level of the first turbulence is reduced, and the flow concentrated toward the center is less likely to occur, and the second and third turbulences are eliminated. This reduces abnormal noise generated in the intake manifold surge tank when the throttle valve is opened. In addition, the rectifying plate suppresses the flow of the flow passing between the throttle valve and the passage wall on the side corresponding to the upstream of the rectifying plate in the passage cross section to the left and right, and the point where the flow goes to the center of the passage is the downstream side. , It is less likely to collide with the flow passing between the throttle valve and the passage wall on the side corresponding to the upstream of the net in the passage cross section, so that the third turbulence is less likely to occur and noise is reduced accordingly. further,
Since the net is provided only in a part of the cross section of the passage, the resistance of the passage does not increase remarkably, and both the suppression of the increase in the passage resistance and the suppression of the abnormal noise are satisfied. According to the abnormal noise reducing structure of the second aspect, the net is arranged on the half section on the side where the throttle valve falls to the upstream side when the throttle valve is opened, so that the first disturbance can be reduced most, and the abnormal noise reducing effect can be obtained. Is big. According to the third aspect of the present invention, since the rectifying plates are arranged in parallel with each other, an excellent noise reduction effect can be obtained both in a low frequency region and in a high frequency region. According to the abnormal noise reducing structure of the fourth aspect, since the rectifying plates are radially arranged, an excellent noise reducing effect is obtained in a relatively low frequency region.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an abnormal noise reduction structure according to a first embodiment and a second embodiment of the present invention.

FIG. 2 is a schematic front view of a portion of a net and a current plate of the abnormal noise reduction structure according to the first embodiment of the present invention.

FIG. 3 is a schematic front view of a portion of a net and a current plate of an abnormal noise reduction structure according to a second embodiment of the present invention.

FIG. 4 is a graph showing abnormal noise reduction characteristics of the structure of the present invention and the structure of a comparative example (including a conventional example).

FIG. 5 is a graph showing abnormal noise reduction characteristics of the first embodiment and the second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Net 2 Throttle valve 3 Intake manifold surge tank 4 Throttle body 5 Intake manifold part 6 Surge tank 7 Rectifier plate 8 Passage wall

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshihiro Nakase 14 Iwatani, Shimowasumi-cho, Nishio-shi, Aichi Japan Auto Parts Research Institute

Claims (4)

[Claims] At least a portion of a cross section of an intake passage downstream of and near a throttle valve is provided with a net, and at least a portion of the remaining portion is provided with a plurality of rectifying plates extending in a direction parallel to an intake passage axis. Abnormal noise reduction structure with air intake. 2. The cross-section of the intake passage, wherein the net is arranged on a half section on the side where the throttle valve falls to the upstream side when the throttle valve is opened, and the plurality of rectifiers are provided on at least a part of the remaining half section. The intake noise reduction structure according to claim 1, wherein a plate is arranged. 3. The intake abnormal noise reduction structure according to claim 1, wherein the plurality of flow straightening plates are arranged in parallel with each other. 4. The intake abnormal noise reduction structure according to claim 1, wherein the plurality of rectifying plates are arranged radially with respect to an axis of the intake passage.