JP5859371B2 - Air intake duct with silencer - Google Patents

Description

The present invention relates to an intake duct with a silencer. In particular, the present invention relates to a suction duct with a silencer provided with a resonance silencer.

Intake ducts are used for various purposes such as supplying air to an internal combustion engine, supplying cooling air, and air conditioning. Air flows through a ventilation path provided inside the intake duct, and necessary air is sent. Further, since the intake duct may be a noise transmission path or a noise generation source, a silencer may be provided.

The intake duct may be provided with a resonance silencer (a so-called resonator or side branch) as a silencer. The resonance silencer is provided so as to branch from the ventilation path of the intake duct. When a resonance type silencer is used, noise of a specific frequency can be effectively silenced.

A so-called whistling sound may occur in an intake duct provided with a resonance silencer. Whistling noise is likely to occur under operating conditions where the air flow rate is large (the flow velocity is high), and when the whistling noise is generated, the noise becomes very loud. Therefore, it is required to prevent the whistling sound from being generated in the intake duct with the resonance silencer.

As a technique for preventing the generation of a whistling sound, for example, there are techniques disclosed in Patent Document 1 and Patent Document 2. Patent Document 1 discloses that air flow control protrusions are formed on the inner surface of a duct main body so as to protrude into the air flow path around the upstream side of the resonator communication hole, thereby suppressing the generation of whistling noise. Further, Patent Document 2 discloses that a whistling sound is formed by forming a duct body so that the peripheral edge of the opening of the duct body leading to the resonator projects outward from the upstream opening edge portion toward the downstream opening edge portion. It is disclosed to suppress the occurrence of.

JP 2008-267210 A JP 2002-240534 A

As a result of the inventor's investigation, the technique disclosed in Patent Document 1 is formed with the flow control protrusion protruding into the air flow path, so that the cross section of the ventilation path is reduced at that portion, and the air ventilation resistance is increased. It turned out to be easy.

In addition, the technology disclosed in Patent Document 1 has a complicated communication pipe shape, such as a shape of a portion where the communication pipe of the resonator is connected to the duct body, and the resonator is designed according to the set frequency. It was found that the frequency deviation of the resonator was likely to occur.

An object of the present invention is to suppress / prevent the generation of whistling noise in an intake duct provided with a resonance silencer by other technical means.

As a result of intensive studies, the inventor has found that if a through hole is provided in the duct wall of the intake duct, the air flow inside the duct can be changed. And when this was applied, it discovered that generation | occurrence | production of a whistling sound could be suppressed and completed this invention.

The present invention is an air intake duct with a silencer in which a duct body for allowing air to flow inside and a resonance silencer are integrated, and the resonance silencer is provided to be branched from the duct body. Has a through hole that connects the inside and the outside of the intake duct at a position close to the portion where the resonance silencer branches, and the through hole is provided at least upstream or downstream of the branch portion. An air intake duct with a silencer (first invention).

In the present invention, it is preferable that the through hole is provided at least upstream of the branch portion (second invention). In the present invention, the duct body is preferably formed in a bent shape, and the resonance silencer and the through hole are preferably provided outside the bent shape (third invention).

According to the intake duct with a silencer of the present invention (first invention), the generation of whistling noise in an intake duct having a resonance silencer can be suppressed / prevented. Furthermore, when the through hole is provided on the upstream side of the branch portion as in the second aspect of the invention, it is possible to more effectively suppress / prevent the whistling sound.

It is a perspective view which shows the external appearance of the air intake duct with a silencer of 1st Embodiment of this invention. It is sectional drawing along the flow direction of the air intake duct with a silencer of 1st Embodiment of this invention. It is a schematic diagram which shows the flow of the air inside the duct in the air intake duct with a silencer of 1st Embodiment of this invention. It is a schematic diagram which shows the flow of the air inside the duct in the conventional intake duct with a silencer. It is a perspective view which shows the external appearance of the air intake duct with a silencer of 2nd Embodiment of this invention. It is a perspective view which shows the external appearance of the air intake duct with a silencer of 3rd Embodiment of this invention.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings, taking as an example an intake duct through which air supplied to an automobile engine flows. The present invention is not limited to the individual embodiments shown below, and can be carried out by changing the form.

The duct member shown in FIGS. 1 and 2 is a synthetic resin intake duct used for a part of a ventilation path of an automobile engine intake system. The intake duct 1 is a member in which a hollow tubular duct body 11 and a Helmholtz resonator 12 are integrally formed. Other duct members, air cleaners, and the like are connected to both ends of the duct body 11, and the duct body 11 forms part of the ventilation path of the automobile engine intake system. In FIGS. 1 and 2, the components connected to the upstream side and the downstream side are omitted, and only the intake duct 1 is illustrated. Moreover, the white arrow in FIG. 1 has shown the direction through which the air which flows through a series of ventilation paths flows.

A resonator 12 integrated with the intake duct 1 is a Helmholtz resonator including a chamber (volume chamber) 13 and a communication pipe 14. The resonator 12 resonates at a specific frequency and has a silencing effect near the resonance frequency. The resonator 12 is a kind of resonant silencer. The resonator 12 is provided so as to branch from the air passage inside the duct body 11. That is, the internal space of the chamber 13 communicates with the air passage of the duct body 11 through the inside of the communication pipe 14.

The duct body 11 of the intake duct 1 is provided with a through hole 15 that allows communication between the inside and outside (outside air) of the intake duct. The through hole 15 is provided in the duct body 11 at a position close to a portion where the resonance silencer (resonator) 12 branches from the duct body 11 (hereinafter abbreviated as “branch portion”). That is, in the present embodiment, a portion where the resonator communication pipe 14 and the duct body are connected is a branching portion. Further, in the present embodiment, one through hole 15 is provided upstream from the branch portion so that the center of the communication pipe 14 and the center of the through hole 15 are aligned along the air flow direction. .

The degree to which the through hole 15 is close to the branch part is preferably determined with respect to the representative dimension of the branch part (in this embodiment, the diameter dimension of the communication pipe), and the through hole 15 is within twice the representative dimension of the branch part. It is preferable to be provided, and it is particularly preferable that the through hole 15 is provided within one time of the representative dimension of the branch portion. If the through hole 15 is too far away from the branch portion, the effect of suppressing and preventing whistling noise is reduced.

The through hole 15 preferably has a diameter of about 1/20 to 1/2 of the diameter of the communication pipe, more preferably about 1/10 to 1/3. The through hole 15 is preferably provided at a position separated from the branch part by a distance of about 1 to 5 times the diameter of the through hole.

In this embodiment, the duct body 11 of the duct member 1 is formed in a bent shape (bent shape). The resonator 12 and the through hole 15 are provided outside the bent shape of the duct (on the side where the radius of curvature of the duct wall is large).

The intake duct 1 of the present embodiment can be manufactured by integral molding by blow molding of synthetic resin (for example, polypropylene resin). The through hole 15 may be drilled in a subsequent process of blow molding. The method of manufacturing the intake duct is not limited to blow molding, and may be manufactured by resin injection molding or other manufacturing methods.

The operation and effect of the intake duct 1 will be described.
The intake duct 1 is used by being placed in a ventilation path through which air is sucked. Then, an air flow from the outside of the duct to the inside occurs in the through hole 15. The inflow air from the through hole changes the flow of air inside the duct body 11 and suppresses the generation of whistling sound. This will be described below.

FIG. 4 is a cross-sectional view schematically showing the flow of air inside the conventional intake duct 9 with a resonance silencer. The difference from the intake duct 1 of the first embodiment is the presence or absence of the through hole 15. In the conventional intake duct 9, a part of the air flow flowing inside the duct collides with the corner C on the downstream side of the part where the communication pipe of the resonator 92 branches, and the flow is disturbed. When the flow velocity of the air flow increases and the turbulence of the flow increases, it is considered that a self-excited vibration caused by the turbulence occurs and a whistling sound is generated.

FIG. 3 schematically shows the flow of air inside the intake duct of the first embodiment. In the intake duct 1, air flows into the duct from the through hole 15. And the flow of the air which flows through the inside of a duct is pushed by the flow from a through-hole, and comes to flow away from the part which a resonator branches. As a result, the air flow is less likely to collide with the corner C on the downstream side of the portion where the communication pipe 14 of the resonator 12 branches, and the generation of whistling noise is suppressed or prevented.

In particular, in the present embodiment, since the through hole 15 is provided upstream of the branch portion, it is possible to more effectively prevent the air flow in the duct from colliding with the corner portion C on the downstream side of the branch portion. It is possible to suppress and suppress the whistling noise.

The present invention is not limited to the above embodiment, and can be implemented with various modifications. Other embodiments of the present invention will be described below. However, in the following description, portions different from the above embodiment will be mainly described, and detailed descriptions of the same portions will be omitted. In addition, the embodiments described below can be implemented by combining some of them or replacing some of them.

FIG. 5 shows an intake duct 2 according to the second embodiment of the present invention. Similarly to the intake duct 1 of the first embodiment, the intake duct 2 also has a duct body 21, a resonance silencer 22, and a through hole 25 is provided in the vicinity of a portion where the silencer branches. In the present embodiment, the resonance silencer is a so-called side branch. In the present invention, the resonance silencer provided so as to be branched from the duct body may be a Helmholtz resonator or a side branch, or may be another resonance silencer. Moreover, what is called a drain hole may be provided in the edge part of the resonance type silencer.

In the present embodiment, the through hole 25 is provided downstream of the portion where the resonance silencer 22 branches. In addition, two through holes 25 are provided side by side in the circumferential direction of the portion where the resonance silencer 22 branches.

Even if the through hole is provided on the downstream side of the branching portion, the flow of air inside the duct can be changed to suppress / prevent the whistling sound. That is, the flow of air flowing from the outside of the duct into the duct through the through hole has a flow component toward the center of the duct and flows so as to swell toward the inside of the duct. As a result, even in the region upstream of the through hole, the flow of air passing through the silencer branch is deflected to the inside of the duct and the whistling noise is suppressed / prevented. In addition, the direction in which the through hole is provided on the upstream side of the branch portion as in the first embodiment described above has a higher effect of suppressing and preventing the whistling noise generation.

Further, if the total cross-sectional areas of the through holes are the same, the effect of suppressing and preventing the whistling noise is enhanced when a plurality of through holes are provided. This is because a range in which a plurality of through holes are provided has a wider range of influence on the air flow flowing through the inside of the duct.

FIG. 6 shows an intake duct 3 according to a third embodiment of the present invention. The intake duct 3 is different from the intake duct 2 of the second embodiment in that through holes 35 and 35 are arranged along the flow direction of the air flow in the duct, and the other points are the same. Even in such an embodiment, the generation of whistling noise can be suppressed / prevented.

Further, in the intake duct 2 of the second embodiment and the intake duct 3 of the third embodiment, the bending of the duct body is smaller than that of the intake duct 1 of the first embodiment. The present invention includes a duct having a relatively large bend in the duct body such as the intake duct 1, a duct having a relatively large bend in the duct body such as the intake duct 2 and the intake duct 3, or a straight tubular duct body. Applicable to intake duct.

Further, in the description of the above embodiment, the description has been made mainly on the example in which the branch portion of the resonance silencer such as the resonator is outside the bent shape of the duct body, but the branch portion and the through hole 15 of the resonator 12 are the duct body. Other positions in the circumferential direction, for example, the inner side of the duct main body or the middle portion between the inner side and the outer side of the bending may be provided. Since a whistling sound is likely to occur when the branching portion such as a resonator is outside the bend, the present invention is particularly useful when the branching portion of the resonance type silencer is provided at the outer portion of the bending of the duct body. .

The silencer-equipped intake duct of the present invention can be applied to other technical fields other than those described in the above embodiment. For example, the intake duct of the present invention can be applied to a blower system for sending cooling air to cool a battery system mounted on an electric vehicle or a hybrid vehicle, a ventilation duct for passing air from an air conditioner or an air conditioning system, etc. it can.

As an example, the intake duct of the first embodiment was manufactured, and a series of intake system parts such as an air cleaner were connected to form an intake system of the engine. The cross section of the intake duct had an equivalent diameter of 60 mm, a communication pipe diameter of 23 mm, and a through hole with a diameter of 5 mm. The through hole was provided at a position 10 mm away from the branching portion upstream. A noise test, a ventilation resistance test, and a resonance frequency measurement test of a resonator were performed on the intake system. As a comparative example, a similar test was performed using an air intake duct having no through hole.

(Noise test)
While measuring noise at a position 10 cm away from the air intake port of a series of intake systems, air was sucked through the intake system by a blower. The flow rate of air flowing through the intake system was increased, and the occurrence of whistling noise was investigated.

While the air flow rate was less than 100 L / sec, no whistling noise was generated in the examples and comparative examples, and the measured noise was at the same level. At an air flow rate of 120 L / sec, whistling noise was not generated in the examples (with through holes), but whistling sounds were generated in the comparative example (without through holes). As a result of noise measurement, the example was 95 dBA and the comparative example was 109 dBA, and the example had a noise reduction effect of about 15 dBA.

(Ventilation resistance test)
The ventilation resistance for flowing predetermined air through the intake system was measured. When the air flow rate was 120 L / sec, the ventilation resistance of the entire intake system was 2.77 kPa in the example and 2.76 kPa in the comparative example, and the increase in ventilation resistance was negligible.
In addition, when the same ventilation resistance measurement was performed in the case where a protrusion that protrudes into the air path as disclosed in Patent Document 1 was provided (Reference Example 1), it was 2.94 kPa, compared with the comparative example. Ventilation resistance increases considerably. That is, according to the intake duct of the present invention, it was confirmed that an effect of suppressing an increase in ventilation resistance can be obtained as compared with the technique disclosed in Patent Document 1 (Reference Example 1).

In the intake ducts of the examples (with through holes) and the comparative examples (without through holes), the resonance frequency of the resonator was measured using an FFT device. In both Examples and Comparative Examples, the resonance frequency was 370 Hz, and there was no difference.
In addition, as disclosed in Patent Document 2, an air intake duct in which a duct body is formed so that a peripheral edge of an opening of a duct body leading to a resonator projects outward from an upstream opening edge portion toward a downstream opening edge portion. (Reference Example 2) and the resonance frequency was measured in the same manner, but the resonance frequency of Reference Example 2 was 386 Hz, which was considerably different from the set frequency of the resonator. In addition, the ringing frequency of Reference Example 1 was 360 Hz, which also deviated from the set frequency of the resonator. That is, according to the intake duct of the present invention, it is possible to suppress a change in the resonance frequency of the resonance silencer compared to the techniques disclosed in Patent Document 1 and Patent Document 2 (Reference Example 1 and Reference Example 2). It was confirmed that an effect was also obtained.

The intake duct with a silencer of the present invention can be used as a part of an intake system that defines an air path through which air is sucked, and has high industrial utility value.

DESCRIPTION OF SYMBOLS 1 Intake duct 11 Duct body 12 Resonator 13 Chamber 14 Communication pipe 15 Through hole 2, 3 Intake duct 21, 31 Duct body 22, 32 Side branch 25, 35 Through hole

Claims (3)

An air intake duct with a silencer in which a duct body that allows air to flow inside and a resonance silencer are integrated,
The resonance silencer is provided to branch from the duct body,
The duct body is provided with a through hole that communicates the inside and outside of the intake duct at a position close to the portion where the resonance silencer branches.
The through-hole is a suction duct with a silencer provided at least upstream or downstream of the branch portion. The intake duct with a muffler according to claim 1, wherein the through hole is provided at least upstream of the branch portion. The duct body is formed in a curved shape,
The intake duct with a silencer according to claim 1 or 2, wherein the resonance-type silencer and the through hole are provided outside the curved shape.

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