JP2729188B2 - Car silencer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a muffler for an automobile for reducing secondary noise in a high frequency region where exhaust gas is generated.

[0002]

2. Description of the Related Art In a conventional muffler for a vehicle, the main body of the muffler is formed for the purpose of expanding the noise in the middle and high frequency range where exhaust gas is generated by the resonance function and reducing the noise in the low frequency range. The outer cylinder is partitioned by a partition plate to form an expansion chamber and a resonance chamber.These chambers are each equipped with an exhaust pipe that forms an exhaust gas inlet from the engine, and a muffled exhaust gas discharge into the atmosphere. Exhaust discharge pipe forming an outlet,
The exhaust communication pipe or one or a plurality of the exhaust pipes are connected to each other by a large number of small holes formed in the peripheral surface thereof. (For example, a conventional silencer shown in Patent Application Publication 63-28201)

[0003]

In the structure of a vehicle silencer comprising an expansion type silencer and a resonance type silencer according to the prior art as described above, the engine is exhausted from an engine to an exhaust introduction pipe, and a large number of exhausts are discharged. Exhaust gas that is going to squirt into the expansion chamber through the small holes will disturb the flow of exhaust gas when passing through a large number of small holes, generating secondary noise in the high frequency range and increasing the sound pressure level. There is a problem that the noise reduction effect due to the expansion effect of the exhaust noise is reduced. In order to solve this problem, a number of small holes around the exhaust pipe are
A method of encapsulating with a sound-absorbing sound-absorbing element using a sound-absorbing material (refer to the embodiment shown in Patent Application Publication No. 63-28201), or generally, a sound-absorbing chamber filled with a sound-absorbing material is used to muffle the sound. Although it is arranged in the outer cylinder that constitutes the main body of the device, the size of the muffler main body increases, the manufacturing cost is increased, and the sound absorbing material is inevitably deteriorated over time.

[0004]

According to the muffler for an automobile of the present invention, the opening on the downstream side of the flow of exhaust gas is in contact with the partition plate and closed from the resonance chamber, and the exhaust gas is introduced by the opening on the upstream side. The present invention is characterized in that a double pipe structure formed by coaxially arranging an exhaust gas introduction pipe in a communication pipe having a configuration in which the pipe communicates with the expansion chamber is disposed in the expansion chamber.

[0005]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a muffler for an automobile according to the present invention.

FIG. 1 is a longitudinal sectional side view showing an embodiment of a vehicle silencer according to the present invention, and FIGS. 2 and 3 are sectional views taken along the lines AA and BB of FIG.

1, 2 and 3, reference numeral 1 denotes an outer cylinder constituting a main body of a muffler, 2 denotes an exhaust introduction pipe, and 3 denotes an upstream of an exhaust introduction pipe 2 forming an introduction port of exhaust gas from an engine. 4 is an opening on the downstream side of the exhaust pipe 2, 5 is a number of small holes formed in the peripheral surface of the exhaust pipe 2, 6 is an exhaust pipe, 7 is a downstream of the exhaust pipe 6. 8 is an opening on the upstream side of the exhaust discharge pipe 6, 9 is a partition plate, 10 is a communication pipe,
Reference numeral 11 denotes an opening on the downstream side of the communication pipe 10 provided on the partition plate 9, 12 denotes an opening on the upstream side of the communication pipe 10, and 13 denotes an exhaust passage formed between the exhaust introduction pipe 2 and the communication pipe 10. A gap, 14 is an expansion chamber, 15 is a resonance chamber, and arrows indicate the direction of the flow of exhaust gas.

The outer cylinder 1 constituting the main body of the silencer is partitioned by a partition plate 9, and an expansion chamber 14 is provided upstream of the flow of exhaust gas.
However, a resonance chamber 15 is formed on the downstream side, and the opening 3 on the upstream side forms an inlet for exhaust gas from the engine, and the opening 3 on the downstream side enters the resonance chamber 15 from the opening 4 on the downstream side. An exhaust pipe 2 having a structure in which exhaust gas is diverted from a large number of small holes 5 formed in the surface to the expansion chamber 14 is connected to the outer cylinder 1.
Near the center. In this case, the opening 4 on the downstream side of the exhaust gas introduction pipe 2 is provided to protrude into the resonance chamber 15.

A large number of small holes 5 are disposed in the expansion chamber 14 so that the exhaust gas flowing from the engine into the exhaust introduction pipe 2 and flowing vigorously downstream can be efficiently diverted to the expansion chamber 14. A portion of the introduction pipe 2 is formed on the peripheral surface of the downstream portion. The downstream opening 7 forms a discharge port for exhaust gas into the atmosphere, and the exhaust discharge pipe 6 communicating with the expansion chamber 14 by the upstream opening 8 is arranged in parallel with the exhaust introduction pipe 2 to form an outer cylinder. 1.

The downstream opening 11 abuts against the partition plate 9 and is closed from the resonance chamber 15. The upstream opening 12 allows the exhaust introduction pipe 2 and the expansion chamber 14 to be separated by a number of small holes 5. A communication pipe 10 having a communication structure is disposed in the expansion chamber 14 with the exhaust introduction pipe 2 provided coaxially inside. in this case,
The communication pipe 10 having a large diameter and the exhaust pipe 2 having a small diameter constitute a double pipe structure, and the communication pipe 1 in contact with the partition plate 9 is formed.
The opening 11 on the downstream side of the resonance chamber 1 is
5 is closed, a gap 13 formed between the two exhaust pipes constituting the double-pipe structure is used for exhaust gas from the engine to flow through the exhaust inlet pipe 2 and to form a large number of peripheral surfaces. An exhaust passage that is discharged toward the expansion chamber 14 through the small hole 5 is formed.

The peripheral surface of the portion of the exhaust introduction pipe 2 protruding into the resonance chamber 15 is non-porous, and the exhaust gas that has entered the exhaust introduction pipe 2 from the engine resonates vigorously from the opening 4 on the downstream side. The noise is introduced into the chamber 15, and the noise in the low frequency region where the exhaust gas is generated is efficiently silenced through the resonance action.

Exhaust gas that has entered the exhaust gas inlet pipe 2 from the engine expands and diffuses, and when a large number of small holes 5 on the peripheral surface of the exhaust gas inlet pipe 2 attempt to vigorously squirt into the expansion chamber 14, a large number of small holes are generated. The flow of the exhaust gas passing through 5 is disturbed, and secondary noise in a high-frequency region is generated to increase the sound pressure level. Exhaust gas to be ejected from the exhaust gas introduction pipe 2 to the expansion chamber 10 with such an action is transmitted by the communication pipe 10 constituting the outer pipe portion of the double pipe structure composed of the communication pipe 10 and the exhaust gas introduction pipe 2. The opening 11 on the downstream side of the communication pipe 10 that is blocked in the direction of the jetting and abuts against the partition plate 9 is closed from the resonance chamber. The turbulence of the exhaust gas is rectified so as to flow from the formed gap 13 toward the expansion chamber 14, and secondary noise in a high-frequency region where exhaust gas passing through the many small holes 5 is generated is efficiently attenuated and the entire sound pressure is reduced. The level is reduced.

As described above, the exhaust pipe 2 is connected to the communication pipe 10.
By forming the exhaust path formed by the double pipe structure having the inside in the expansion chamber 14, the secondary noise in the high frequency region generated when passing through the many small holes 5 of the exhaust introduction pipe 2 is, for example, The exhaust gas is efficiently attenuated without using a method of enclosing the porous exhaust pipe with the sound absorbing type silencing element, and the exhaust gas introduced into the expansion chamber 14 is expanded and diffused there to be silenced, and then the exhaust discharge pipe 6 is exhausted. And is released into the atmosphere vigorously.

[0014]

As described above, the vehicle silencer according to the present invention efficiently reduces secondary noise in a high frequency region generated when exhaust gas passes through a number of small holes in an exhaust introduction pipe,
Decrease overall sound pressure level. Further, since an excellent noise reduction effect is achieved without using a sound absorbing type noise reduction element using a sound absorbing material such as glass wool, manufacturing costs can be reduced except for the cause of deterioration of the muffler over time.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an automotive silencer according to the present invention.

FIG. 2 and

FIG. 3 is a cross-sectional view taken along a line AA and a line BB of FIG. 1;

FIG. 4 is a side sectional view of a muffler showing one embodiment according to the prior art.

[Explanation of symbols]

In each of the drawings, 1 is an outer cylinder, 2 is an exhaust introduction pipe, 3 and 4 are openings of the exhaust introduction pipe, 5 is a number of small holes, 6 is an exhaust discharge pipe, and 7 and 8 are openings of the exhaust discharge pipe. Part, 9 is a partition plate, 10
Is a communication pipe, 11 and 12 are openings of the communication pipe, 13 is a gap, 14 is an expansion chamber, and 15 is a resonance chamber.

Claims (1)

(57) [Claims] An outer cylinder constituting a main body portion of a silencer is partitioned by a partition plate, an expansion chamber is formed on an upstream side of a flow of exhaust gas, and a resonance chamber is formed on a downstream side, and an opening on an upstream side is an engine. An exhaust gas inlet, and an exhaust gas inlet pipe through which exhaust gas flows from the downstream opening to the resonance chamber, and from a large number of small holes formed in the peripheral surface to the expansion chamber, The opening of the exhaust muffler forms an outlet for exhaust gas into the atmosphere, and the exhaust muffler communicating with the expansion chamber by the opening on the upstream side is disposed in parallel with the outer cylinder in a muffler for an automobile. ,
The downstream opening is in contact with the partition plate and the resonance chamber is closed, and the exhaust introduction pipe is coaxially inserted into a communication pipe configured so that the exhaust introduction pipe and the expansion chamber communicate with each other through the upstream opening. A muffler for an automobile, wherein a double-pipe structure formed and disposed is disposed in an expansion room.