JP2009115053A - Noise control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a noise control device capable of suppressing intake noise from becoming a roaring sound. <P>SOLUTION: In this noise control device, a target A of intake noise is set, and the intake noise is made to approach the preset target A using a plurality of resonators 20. By setting the preset target A so that the intake noise becomes linearly big as the frequency becomes high (as the engine rotation speed becomes high), for example, a waveform on a graph of a transfer function dB to a frequency Hz can be suppressed from becoming vertically fluctuated. Therefore, the intake noise can be suppressed from becoming a roaring sound as compared with before. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a noise control device provided in an engine intake system of a vehicle.

  It is known to provide a Helmholtz type resonator in an engine intake system of a vehicle (see, for example, Patent Document 1). The Helmholtz resonator is provided to attenuate sound having a predetermined frequency. When the Helmholtz type resonator is used, as shown in FIG. 5, sound having a predetermined frequency can be attenuated, but anti-resonance occurs at frequencies around the frequency to be attenuated.

However, the conventional noise control device has the following problems.
Since the conventional resonator is provided only for attenuating sound of a predetermined frequency, the waveform in the graph of transfer function [dB] versus frequency [Hz] undulates up and down as shown by the solid line in FIG. It becomes a waveform. Therefore, when the engine speed is gradually increased (when the frequency is increased), the intake noise becomes a swelling sound, and the passengers in the car feel uncomfortable (discomfort, uncomfortable feeling). End up.
JP 2000-110543 A Special Table 2000-500204

  The objective of this invention is providing the noise control apparatus which can suppress that an intake noise turns into a wavy sound.

The present invention for achieving the above object is as follows.
(1) A noise control device including a plurality of resonators and provided in an engine intake system of a vehicle,
A noise control device in which a target of intake noise is set and is brought close to the target set in advance using the plurality of resonators.
(2) The noise control device according to (1), wherein the target is set so that the intake noise increases linearly as the frequency increases.
(3) At least two or more resonators of the plurality of resonators are provided adjacent to each other, and the adjacent resonators share a part of the side wall constituting the volume portion of the resonator, (1 ) The noise control device described.

According to the noise control device of the above (1) or (2), the target of the intake noise is set and brought close to the target set in advance using a plurality of resonators. By setting so that the intake noise increases linearly as the engine speed increases, the waveform in the graph of the transfer function [dB] versus frequency [Hz] becomes a waveform that undulates up and down. Can be suppressed. Therefore, it can suppress that an intake noise turns into a sound with a wave compared with the past.
According to the noise control device of (3) above, at least two of the plurality of resonators are provided adjacent to each other, and a part of the side wall constituting the volume portion of the resonator is formed by the adjacent resonators. Since they are shared, the material cost can be reduced and the space for arranging the resonators can be reduced as compared with the case where a part of the side wall constituting the volume part of the resonator is not shared.

Below, the noise control apparatus of this invention Example is demonstrated using FIGS. 1-4.
As shown in FIG. 1, a noise control device 10 according to an embodiment of the present invention is a noise control device that includes a resonator 20 and is provided in an engine intake system of a vehicle.

The resonator 20 is provided in a duct 30 that is an engine intake system disposed upstream of the engine in the intake flow direction. The duct 30 may be a duct and a hose on the upstream side of an air cleaner (not shown), or may be a duct, a pipe, a connector, and a hose on the downstream side of the air cleaner.
The resonator 20 is a Helmholtz type resonator. The resonator 20 is not a so-called variable frequency resonator that can change the frequency that can be attenuated. The frequency that the resonator 20 can attenuate (mute) is constant (not fixed or variable).

The equation for calculating the attenuation frequency of the resonator 20 is:
f = (c / 2π) [S / {V (L + 1.6a)}] ^1/2 (i)
It is.
here,
f is attenuation frequency c is sound velocity S is resonance tube (neck) cross-sectional area V is volume L is resonance tube (neck) length a is resonance tube (neck) radius.
As can be seen from the equation (i), the attenuation frequency of the resonator 20 depends on the cross-sectional area S of the resonance tube (neck), the length L of the resonance tube (neck), and the volume V.

  A plurality of resonators 20 are provided. The cross-sectional shape of the volume portion 21 of each resonator of the plurality of resonators 20 may be a rectangle, a polygon other than a rectangle (triangle or more), a circle, or an ellipse. Or other shapes. Moreover, the cross-sectional shape of the resonance tube (neck portion) 22 of each resonator of the plurality of resonators 20 may be a rectangle, a polygon other than a rectangle (triangle or more), or a circle. It may be oval or other shapes.

  The resonance tube 22 is formed of a through hole provided in the bottom wall of the wall constituting the volume portion 21, and the cross-sectional area of the hole is the cross-sectional area of the resonance tube, and the length of the hole (plate thickness of the bottom wall) is the length of the resonance tube. However, the resonance tube 22 does not have to be a through hole provided in the bottom wall of the wall constituting the volume portion 21, and is a hose-like one extending from the bottom wall of the wall constituting the volume portion 21 toward the duct 30. (Tube having a length) may be used.

  At least two or more resonators of the plurality of resonators 20 are provided in the same mounting space in an unillustrated engine room and are provided adjacent to each other. Adjacent resonators 20 share a part of the side wall 21 a constituting the volume 21 of the resonator 20. The two or more resonators 20 adjacent to each other include, for example, a plurality of volume portions 21 by providing a partition wall in one relatively large volume portion, and one volume portion 21 is provided in each volume portion 21. It is formed by providing a resonance tube 22 that directly communicates with the inside of the duct 30.

  The attenuation frequencies of at least two resonators of the plurality of resonators 20 are different from each other. The attenuation frequency of at least two (but not all) of the plurality of resonators 20 is different from the attenuation frequency of at least one other resonator. At least one of the resonance tube (neck) cross-sectional area S, the resonance tube (neck) length L, and the volume V of at least two resonators of the plurality of resonators 20 is different from at least one other resonator. .

  The plurality of resonators 20 are set (controlled) in frequency and attenuation so as to approach the target A (see FIG. 4) of intake noise set in advance. Note that “approaching” means that the deviation of the intake noise set in advance from the target A in FIG. 4 is within ± 5 dB, preferably within ± 3 dB, and more preferably within ± 1 dB. However, numerical values such as ± 5 dB can be changed as appropriate.

  The target A of the intake noise set in advance is, for example, as shown in the waveform in the graph of the transfer function [dB] versus frequency [Hz] in FIG. Therefore, the intake noise is set to increase linearly. However, the target A may not be set so that the intake noise increases as the frequency increases. Further, the target A may not be a straight line, may be a curved line, or may be another line in the graph of FIG.

Here, FIG. 4 will be described.
FIG. 4 shows a graph of transfer function [dB] versus frequency [Hz]. In FIG. 4, the dotted line indicates the case where only one resonator is provided in the duct 30, the one-dot chain line indicates the case where only one other resonator is provided in the duct 30, and the two-dot chain line indicates The case where only one other resonator different from the two resonators is provided in the duct 30 is shown, and the solid line shows the case where all the three resonators are provided in the duct 30.

The following can be seen from FIG.
Each resonator can attenuate the sound of the respective attenuation frequency. However, if only one resonator is provided, the waveform is greatly waved up and down (wavy), and the intake noise becomes a undulating sound. Therefore, in order to bring the waveform closer to the target A using a resonator, a plurality of resonators (preferably 10 or more, more preferably 15 or more, but may be 10 or less in some cases) are required. .
By providing a plurality of resonators so as to bring the waveform closer to the target A rather than simply for attenuating the sound, the plurality of resonators 20 can be used to bring the waveform closer to the target A.

Next, the operation of the embodiment of the present invention will be described.
In the embodiment of the present invention, the target A of the intake noise is set and brought close to the preset target A using the plurality of resonators 20, so that the preset target A is increased as the frequency becomes higher (engine rotation, for example). By setting the intake noise so as to increase linearly (as the number increases), it is possible to suppress the waveform in the graph of the transfer function [dB] vs. frequency [Hz] from being waved up and down. Therefore, it can suppress that an intake noise turns into a sound with a wave compared with the past.

  Since at least two or more resonators 20 of the plurality of resonators 20 are provided adjacent to each other, and the adjacent resonators 20 share a part 21a of the side wall constituting the volume portion 21 of the resonator 20, Compared with the case where a part of the side wall 21a constituting the volume portion 21 of the resonator 20 is not shared, the material cost can be reduced and the arrangement space of the resonator 20 can be reduced. Since material costs can be reduced, the resonator 20 can be reduced in weight. Further, since the space for arranging the resonator 20 can be reduced, it is advantageous in terms of the space for mounting the resonator 20.

  In order to approach the target A set in advance using the plurality of resonators 20, it is not necessary to provide (add) additional resonators after providing the plurality of resonators 20 to approach the target A. Therefore, it is not necessary to design a new resonator after providing a plurality of resonators 20 in order to approach the target A. Therefore, the cost can be reduced compared to the case where a new resonator design is required.

  Since a plurality of resonators 20 are used to approach the target A set in advance, the problem of anti-resonance that is generally a problem when using one resonator does not occur.

  Of course, the present invention can deal with intake noise, but it can also be used when there is a need to generate sound or attenuate external sound, such as an engine cover, an engine undercover, and an air conditioning duct. it can.

It is a perspective view which shows the case where the noise control apparatus of this invention Example is provided in the engine intake system. It is a see-through | perspective perspective view of the noise control apparatus of this invention Example. It is sectional drawing of one resonator among the several resonators of the noise control apparatus of this invention Example. It is a graph of the transfer function [dB] vs. frequency [Hz] of the noise control apparatus of the present invention, where the dotted line shows the case where only one resonator is provided in the duct, and the alternate long and short dash line is the other resonator in the duct. In the case where only two resonators different from the two resonators are provided in the duct, the solid line indicates the case where all the three resonators are provided in the duct. It is shown and is a graph when the preset target is set so that the intake noise increases linearly as the frequency increases. It is a graph of transfer function [dB] vs. frequency [Hz] when one conventional resonator is provided.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Noise control apparatus 20 Resonator 21 Volume part 21a Side wall part 22 which comprises volume part Resonance tube 30 Duct

Claims (3)

A noise control device including a plurality of resonators and provided in an engine intake system of a vehicle,
A noise control device in which a target of intake noise is set and is brought close to the target set in advance using the plurality of resonators.   The noise control device according to claim 1, wherein the target is set so that the intake noise increases linearly as the frequency increases.   2. The resonator according to claim 1, wherein at least two or more resonators of the plurality of resonators are provided adjacent to each other, and the adjacent resonators share a part of a side wall constituting a volume portion of the resonator. Noise control device.

Images