JPS593131Y2 - exhaust silencer - Google Patents

Description

[Detailed description of the invention] This invention reduces high-frequency sound in exhaust noise, and
This invention relates to an exhaust muffler that also reduces low frequency sounds.

Conventionally, exhaust silencers are installed at the exhaust gas discharge part of internal combustion engines for the purpose of reducing exhaust noise from internal combustion engines.
Exhaust mufflers with built-in sound-absorbing material in an expansion chamber divided into two or more chambers are widely used, but exhaust mufflers with such a sound-absorbing expansion chamber have the effect of reducing high-frequency sound. First, there was no effect of reducing low-frequency sounds specific to exhaust noise.

On the other hand, exhaust silencers are also mass-produced, which have a resonance chamber combined with an expansion chamber to attenuate sound waves in the exhaust noise of automobile internal combustion engines.
Sound-absorbing materials with built-in sound-absorbing materials are not used.
Therefore, there was a drawback that a high silencing effect could not be obtained.

Therefore, in order to eliminate the above-mentioned conventional drawbacks, the present invention provides an exhaust system that can effectively reduce high-frequency sounds and low-frequency sounds by providing a resonance chamber in the partition plate member between two sound-absorbing expansion chambers. The purpose is to provide a silencer.

That is, in the present invention, a resonance chamber that resonates at a frequency of 150 Hz to 250 Hz is provided around a communicating tube that communicates two sound-absorbing expansion chambers, and the resonance chamber that resonates at a frequency of 150 Hz to 250 Hz is provided in communication with the communicating tube, and the end portion of the communicating tube is The exhaust muffler has a plurality of exhaust flow holes that communicate with the expansion chamber.

Embodiments of the present invention will be described below with reference to the drawings.

In the exhaust silencer according to Embodiment 1 of the present invention shown in FIGS. 1 and 2, exhaust gas from an internal combustion engine (not shown) is introduced from the inlet portion 8 as shown by arrow E, and the exhaust gas is introduced into the first expansion chamber. The gas is expanded in the second expansion chamber 2 through a plurality of exhaust gas flow holes 6 provided in the communication pipe 10 of the partition plate member 5, and is then discharged from the outlet portion 9. ing.

Therefore, the first expansion chamber 1 and the second expansion chamber 2 are formed into sound-absorbing expansion chambers whose inner walls are lined with heat-resistant glass wool 7, which is a sound-absorbing material, and mainly absorb high-frequency sounds of exhaust gas noise. It is being reduced.

Further, around the communication pipe 10 of the partition plate member 5, a resonance chamber 3 is provided which is communicated with by a plurality of small holes 4, and the exhaust gas is passed from the first expansion chamber 1 through the communication pipe 10 to the second 150 Hz in this resonance chamber 3 before being introduced into the expansion chamber 2
The resonant frequency within the frequency range from 250 Hz to 250 Hz muffles the low frequency sound.

Therefore, this resonance chamber 3 has a frequency of 150 Hz to 250 Hz.
The volume of the resonance chamber 3 should be between 15% and 25% of the volume of the exhaust muffler.
The damping characteristics should be adjusted accordingly.

Furthermore, the high-frequency sound of the exhaust gas introduced from the communication pipe 10 into the second expansion chamber 2 and expanded is reduced again by the heat-resistant glass wool 7 on the inner wall surface, and the high-frequency sound is reduced again by the heat-resistant glass wool 7 on the inner wall surface. It is discharged to the outside via a plurality of exhaust gas flow holes 6.

Next, the exhaust silencer according to the second embodiment of the present invention shown in FIGS. 3 and 4 has the same configuration as the first embodiment, and the same parts are indicated by the same part numbers. The difference is that the inlet section 8 and the outlet section 9 of the exhaust gas shown by the arrow E are provided in the same direction, and have the same function as the first embodiment.

According to the present invention, a resonance chamber that resonates at a frequency of 150 Hz to 250 Hz is provided around the communication tube that communicates the two sound-absorbing expansion chambers, so that it communicates with the communication tube.
The sound-absorbing expansion chamber mainly attenuates high-frequency sounds of exhaust gas noise, and before the exhaust gas is introduced from one expansion chamber to the other expansion chamber via the communication pipe, a resonance chamber is used to
The infrasound can be attenuated by a resonant frequency within the frequency range of 150 Hz to 250 Hz.

In addition, the high-frequency sounds in the exhaust gas noise are sufficiently attenuated in the two sound-absorbing expansion chambers, and the low-frequency sounds are reduced to 150 H.
Since the noise is attenuated by a resonant chamber that resonates at a frequency of 250 Hz, the exhaust silencer of the present invention can easily obtain the necessary attenuation characteristics for the exhaust noise reduction target value. By forming approximately 15 to 25% of the exhaust muffler volume and further adjusting it according to its damping characteristics,
Low-frequency sounds can be sufficiently attenuated, and the silencing effect can be further improved.

As a result, the exhaust muffler itself can be made compact, and the audible characteristics are also very good.

In addition, since the communication pipe is communicated with the sound-absorbing expansion chamber through a plurality of exhaust flow holes drilled at its end, noise from the expansion chamber into the communication pipe is detoured through the exhaust flow holes, and the plurality of exhaust Noise suppression by the pipe wall between the communication holes is combined with the effects of the sound-absorbing expansion chamber and the resonance chamber, and the noise reduction effect can be further improved compared to the case where the communication pipe is completely opened into the expansion chamber. can.

Therefore, according to the present invention, it is possible to provide an exhaust muffler that can effectively reduce high-frequency sounds and low-frequency sounds in exhaust noise.

Note that the present invention can be particularly effectively applied to exhaust mufflers for internal combustion engines that drive generators, wells, construction machinery, and the like.

[Brief explanation of drawings]

1 and 2 are a side sectional view and a vertical sectional view taken along the line AA in FIG. 1, respectively, of an exhaust muffler according to a first embodiment of the present invention, and FIGS. 3 and 4 are an embodiment of the present invention. 2, the side sectional view and B- of FIG. 3, respectively.
It is a longitudinal cross-sectional view in the direction of the B line. 1...First expansion chamber, 2...Second expansion chamber, 3...Resonance chamber, 5...Partition plate member,
7...Heat-resistant glass wool, 10...
Communication pipe.

Claims (1)

[Scope of utility model registration request] 150 around the communication pipe that communicates the two sound-absorbing expansion chambers.
An exhaust muffler comprising: a resonance chamber that resonates at a frequency from Hz to 250 Hz, which communicates with the communication pipe; and a plurality of exhaust flow holes which communicate with the expansion chamber at the end of the communication pipe.