JP4561429B2 - Intake system sound propagation structure - Google Patents

Description

  The present invention relates to an intake system generated sound propagation structure that propagates sound generated in an intake system to a passenger compartment.

For users who prefer a sporty feeling of acceleration, a plurality of intake ducts having different resonance frequencies are provided to generate a powerful intake sound during acceleration. Note that the intake port is disposed in a cowl part that easily propagates high-frequency sound into the vehicle interior and a fender part that easily propagates low-frequency sound into the vehicle interior (see Patent Document 1).
JP 2000-303925 A

However, since the sound generated in the fender portion is easily propagated not only to the passenger compartment but also to the outside of the vehicle, if the intake duct and the intake port are arranged in the fender portion as in the conventional example described in Patent Document 1, the outside of the vehicle is There is a problem of increasing noise.
Therefore, the present invention has been made paying attention to the above points, and it is an object of the present invention to provide an intake system generated sound propagation structure capable of propagating intake system generated sound to the passenger compartment while suppressing outside noise.

In order to solve the above problems, an intake system generated sound propagation structure according to the present invention includes a resonator that is connected to an intake duct of an engine and that reduces intake noise generated in the intake duct, and is used as a resonator when reducing intake noise. Using the generated vibration energy as a sound source, the frequency of the natural vibration of the outer wall constituting the resonator is matched to the frequency region where the resonator can reduce the intake sound, and the resonator has multiple outer walls with different natural vibration frequencies. In this way, the propagation of vibration energy to the passenger compartment is promoted, and in the engine compartment where the engine is stored, the sides and the lower side of the resonator are covered with a partition wall, so that at least the vehicle width direction, the vehicle front-rear direction, and the vehicle It is characterized by suppressing the downward propagation to the outside of the vehicle. There are two paths through which the vibration energy propagates to the passenger compartment: air between the resonator and the passenger compartment, or a vehicle body member between the resonator and the passenger compartment.

  According to the intake system generated sound propagation structure according to the present invention, the intake sound generated in the intake duct itself is not used as in the prior art, but the intake sound generated in the intake duct is reduced by the resonator, and the resonator is used instead. By using the vibration energy generated in the vehicle as a sound source and promoting the propagation of this vibration energy to the passenger compartment and suppressing the propagation to the outside of the vehicle, it is possible to transmit the intake system generated sound to the occupant while suppressing the noise outside the vehicle.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a first embodiment of the present invention. An engine room 2 for storing the engine 1 is disposed in front of the vehicle compartment 4 via a dash panel 3. Further, the side of the engine room 2 is adjacent to a fender 6 via a fender apron 5, and the fender 6 is covered with a fender panel 7.
The intake duct 8 of the engine 1 has an intake port 8 a in the fender 6, passes through the fender 6 to the engine room 2, and is connected to the engine 1 via an air cleaner 9 that performs intake air cleaning. In addition, a resonator 10 for reducing intake noise is branched and connected in the vicinity of the intake port 8a of the intake duct 8.

  The resonator 10 is formed of a substantially rectangular hollow box using the principle of Helmholtz resonance, and is configured to reduce a predetermined frequency region of the intake sound. The frequency of the natural vibration of the outer wall (six surfaces here) constituting the resonator 10 is matched to the frequency region where the resonator 10 can reduce the intake sound (for example, 0.5 in the frequency region where the intake sound can be reduced). (Range of up to 2.0 times), and the frequency of each natural vibration is set to be different. The frequency of the natural vibration of the outer wall is adjusted by adjusting the thickness and outer dimensions or attaching a mass. Further, the adjustment of the frequency region that can be reduced by the resonator 10 is performed by adjusting the volume, the duct diameter, the length, and the like.

  The resonator 10 is disposed at a corner of the engine room 2 on the vehicle compartment side, and the side and the lower side (other than the upper side) are covered with the dash panel 3, the fender apron 5, and the partition wall 11. That is, the partition wall 11 is connected to the dash panel 3 and the fender apron 5 so as to surround a corner of the engine room 2 on the vehicle compartment side, and the resonator 10 is accommodated in a space opened only above this. As shown in FIG. 2, the resonator 10 is elastically supported (vibration-proof mount) on its lower surface and side surfaces.

Next, the function and effect of the first embodiment will be described.
Since the intake noise generated near the intake port 8a of the intake duct 8 can be reduced by the resonator 10, it is possible to reliably suppress noise outside the vehicle. At this time, vibration energy due to resonance action is generated in the resonator 10, so that this vibration energy is used as a sound source instead of the intake sound, and the propagation to the passenger compartment 4 is promoted and the propagation to the outside of the vehicle is suppressed, Resonator vibration noise, that is, intake system generated sound can be transmitted to the occupant while suppressing outside noise.

First, the vibration energy generated in the resonator 10 can be increased by matching the natural vibration frequency of the outer wall (here, six surfaces) constituting the resonator 10 to a frequency region in which the resonator 10 can reduce intake sound. . Thereby, the sound pressure level of the resonator vibration sound can be increased, and the propagation to the passenger compartment 4 can be promoted.
Further, by configuring the resonator 10 with a plurality of outer walls having different natural vibration frequencies, it is possible to increase the frequency region in which the sound pressure level of the resonator vibration sound is increased, and to promote the propagation to the vehicle compartment 4. it can. Thus, as shown in FIG. 3, the relationship between the engine speed and the sound pressure level, when the resonator 10 is composed of a plurality of outer walls having different natural vibration frequencies, the natural vibration frequency is limited to a single outer wall. The sound pressure level when the engine speed increases can be kept substantially constant as compared with the case of the configuration. That is, it is possible to provide a comfortable sound for the occupant when the resonator 10 is composed of a plurality of outer walls having different natural vibration frequencies.

Then, a part of the dash panel 3 serving as an inner wall surface of the engine room 3 on the vehicle compartment side , a fender apron 5, and a partition wall 11 cover the sides and the lower side of the resonator 10, so that the resonator vibration sound propagates to the vehicle compartment 4. It is possible to arrange the resonator 10 in a place where it is easy to perform, and to radiate only the component of the resonator vibration sound in the direction (upward) that is easy to hear from the passenger compartment 4, thereby promoting the propagation of the resonator vibration sound to the passenger compartment 4. it can. On the other hand, the lateral vibration (vehicle width direction, vehicle front-rear direction) and the downward component of the resonator vibration sound that is likely to generate noise outside the vehicle are blocked by the dash panel 3, the fender apron 5, and the partition wall 11. Can be suppressed.

Here, FIG. 4 and FIG. 5 are the results of experiments on the ease of sound transmission to the passenger compartment and the outside of the vehicle using speakers, and the sound insulation degree according to the frequency is shown in FIG. It shows the results of observation at three reference points on the hood lock side, inside the fender, and inside the bulkhead.
As shown in FIGS. 4 and 5, in the fender compared to the reference point, it is easy to hear in the passenger compartment 4 when the frequency is about 200 Hz or less, but it is easy to hear outside the vehicle when the frequency is about 150 to 350 Hz. Therefore, it is difficult to propagate the resonator vibration sound to the passenger compartment 4 while suppressing noise outside the vehicle. On the other hand, in the bulkhead, the vehicle compartment 4 is more audible than the reference point in almost the entire frequency range, and the ease of hearing outside the vehicle is not significantly different from the reference point. It can propagate to the passenger compartment 4.

In the first embodiment, the resonator 10 is connected to the upstream side of the air cleaner 9. However, the present invention is not limited to this, and the resonator 10 is arranged downstream of the air cleaner 9 as shown in FIG. You may connect to the side.
Moreover, in said 1st Embodiment, while arrange | positioning the resonator 10 in the corner by the side of the compartment of the engine room 2, it is covered with the dash panel 3, the fender apron 5, and the partition 11, but it is limited to this. is not. In short, it is only necessary to arrange the resonator 10 on the passenger compartment side of the engine room 2 and to cover the side and the lower side thereof. And the partition wall 11 may be formed so as to cover it.

Next, a second embodiment of the present invention will be described with reference to FIGS.
FIG. 8 is a schematic configuration diagram of the second embodiment of the present invention. An engine room 2 that houses the engine 1 is disposed in front of the vehicle compartment 4 via a dash panel 3 (corresponding to “body member”). Further, the side of the engine room 2 is adjacent to a fender 6 via a fender apron 5, and the fender 6 is covered with a fender panel 7.
The intake duct 8 of the engine 1 is connected to the engine 1 via an air cleaner 9 that performs intake cleaning, and a resonator 10 that reduces intake noise is branched and connected to the downstream side of the air cleaner 9.

The resonator 10 is formed of a substantially rectangular hollow box using the principle of Helmholtz resonance, and is configured to reduce a predetermined frequency region of the intake sound. In addition, as shown in FIG. 9, the resonator 10 has a dash panel in which one surface of the outer wall is open, and this open surface is closed by a dash panel 3 that is an inner wall surface on the vehicle compartment side of the engine room 2. 3 is connected. That is, the dash panel 3 constitutes a part of the outer wall of the resonator 10. The frequency of the natural vibration of the dash panel 3 at the site where the open surface of the resonator 10 is blocked is matched to the frequency region where the resonator 10 can reduce the intake sound (for example, 0.5 in the frequency region where the intake sound can be reduced). ~ 2.0 times range). The frequency of the natural vibration of the dash panel 3 is adjusted by adjusting the area that closes the open surface of the resonator 10, reinforcing it with a bead, or attaching a sound absorbing material or a damping material. Further, the adjustment of the frequency region that can be reduced by the resonator 10 is performed by adjusting the volume, the duct diameter, the length, and the like.
In addition, an elastic body 12 made of rubber, for example, is interposed at the connecting portion between the resonator 10 and the dash panel 3 to seal the open surface of the resonator 10. The neck portion 10a connecting the resonator 10 main body and the intake duct 8 is formed in a bellows shape.

Next, the function and effect of the second embodiment will be described.
Since the intake sound generated in the intake duct 8 can be reduced by the resonator 10, it is possible to reliably suppress the noise outside the vehicle. At this time, vibration energy due to resonance action is generated in the resonator 10, so that this vibration energy is used as a sound source instead of the intake sound, and the propagation to the passenger compartment 4 is promoted and the propagation to the outside of the vehicle is suppressed, Resonator vibration noise, that is, intake system generated sound can be transmitted to the occupant while suppressing outside noise.

  That is, by connecting the vibration energy radiation surface of the resonator 10 to the dash panel 3, the dash panel 3 can be vibrated like a speaker diaphragm by the generated vibration energy. Can be propagated. In addition, by vibrating the dash panel 3 that is the inner wall surface of the engine room 2 on the passenger compartment side, the resonator vibration sound is directly radiated to the passenger compartment 4, so that external noise can be suppressed.

Moreover, the dash panel 3 is directly vibrated by opening one surface of the outer wall constituting the resonator 10 and connecting the resonator 10 to the dash panel 3 so that the open surface is closed by the dash panel 3. Therefore, the sound pressure level of the resonator vibration sound can be increased, and the propagation to the passenger compartment 4 can be promoted.
Further, since the dash panel 3 that is the inner wall surface of the engine room 2 on the vehicle compartment side is employed as the vehicle body member that propagates vibration energy to the vehicle compartment 4, the above-described effects can be easily obtained.

Further, the vibration energy generated in the resonator 10 can be increased by matching the natural vibration frequency of the dash panel 3 constituting a part of the outer wall of the resonator 10 to a frequency region in which the resonator 10 can reduce intake sound. it can. Thereby, the sound pressure level of the resonator vibration sound can be increased, and the propagation to the passenger compartment 4 can be promoted.
Due to the above-described effects, the inventors' experiments have revealed that the resonator vibration sound increases by about 10 dB, particularly in a frequency region (for example, 150 to 400 Hz) that the passenger wants to hear.

  Furthermore, an elastic body 12 is interposed in the connecting portion between the resonator 10 and the dash panel 3 and the open surface of the resonator 10 is sealed, so that leakage of intake sound can be prevented. Further, the elastic body 12 and the bellows structure formed on the neck 10 of the resonator 10 can prevent unnecessary vibration from the engine 1 from being transmitted to the dash panel 3 through the intake duct 8 and the resonator 10. it can.

In the second embodiment, the resonator 10 is connected to the dash panel 3. However, the present invention is not limited to this. For example, as shown in FIG. 10, the resonator 10 is connected to the fender apron 5. Also good. In short, as long as it is a vehicle body member capable of transmitting vibration energy to the passenger compartment 4, the above-described effects can be obtained even if the resonator 10 is connected to any other member.
In the first and second embodiments, the configuration of the front engine has been described. However, the present invention is not limited to this, and the present invention may be applied to the configuration of the rear engine.

It is a schematic block diagram of 1st Embodiment. It is a figure which shows the support structure of a resonator. It is a graph which shows the relationship between an engine speed and a sound pressure level. It is an experimental result which shows the ease of sound transmission to the passenger compartment. It is an experimental result which shows the ease of sound transmission outside the vehicle. It is a figure which shows the observation point of experiment. It is a modification regarding arrangement | positioning of an intake duct and a resonator. It is a schematic block diagram of 2nd Embodiment. It is a figure which shows the connection part of a dash panel and a resonator. It is a modification regarding arrangement | positioning of a resonator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Engine room 3 Dash panel 4 Car compartment 5 Fender apron 6 Fender 7 Fender panel 8 Intake duct 8a Inlet 9 Air cleaner 10 Resonator 10a Neck part 11 Bulkhead 12 Elastic body

Claims (4)

Resonator connected to the intake duct of the engine to reduce the intake noise generated in the intake duct,
The vibration energy generated in the resonator when reducing the intake sound is used as a sound source, and the frequency of the natural vibration of the outer wall constituting the resonator is adjusted to the frequency region in which the resonator can reduce the intake sound, and the resonator By forming a plurality of outer walls having different natural vibration frequencies , the propagation of the vibration energy to the passenger compartment is promoted , and the side and lower sides of the resonator are covered with partition walls in the engine room in which the engine is stored. Thus , an intake system-generated sound propagation structure is characterized in that the propagation to the outside of the vehicle toward at least the vehicle width direction, the vehicle front-rear direction, and the vehicle lower direction is suppressed. Consists of an inner wall surface on the passenger compartment side of the engine room that houses the engine , and has a dash panel that can propagate vibration energy to the passenger compartment,
Intake system generated sound propagating structure according to claim 1, characterized in that at least one surface of the outer wall constituting the resonator was connected to the dash panel. The opening surface formed on a part of the outer wall constituting the resonator, such that the opening face is closed by the dash panel, according to claim 2, characterized in that the concatenation of the resonator to the dash panel Intake system generated sound propagation structure. The intake system generated sound propagation structure according to claim 2 or 3 , wherein the resonator is connected to the dash panel via an elastic body.

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