JPS5823922Y2 - Silencer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a muffler installed in an exhaust system of an automobile engine.

In general, a muffler introduces exhaust gas into a sealed casing in which both ends of a cylindrical can body are closed by end plates. However, especially in the case of expansion, many exhaust gas pipes are installed in the exhaust pipes.
It is discharged into the internal space (expansion chamber) of the casing through a small hole with a diameter of 3 rran.

However, since high-temperature exhaust gas flows into this exhaust pipe, oxidation (in particular, peak effects of high-temperature oxidation and low-temperature oxidation appear at high temperatures of 800° C. and low temperatures of 300° C., respectively).

) occurs, and as this oxidative corrosion grows, or as tar, carbon, etc. contained in the exhaust gas grow when discharged through the small holes, these small holes are likely to become clogged. When this clogging occurs, back pressure increases significantly,
There are many cases where engine performance is degraded.

In order to prevent this clogging, it is possible to make the small holes larger in diameter, but even if this prevents clogging, it is not possible to expand the exhaust gas, and as a result, the sound cannot be muffled. Therefore, the exhaust gas simply flows through.

The present invention was made in order to eliminate such conventional trade-offs, and although it prevents clogging, the silencing effect does not deteriorate, and even if clogging occurs, back pressure does not increase. To provide a silencer which prevents noise from occurring and has a simple configuration.

Hereinafter, the silencer according to the present invention will be explained with reference to the drawings.

The figure is a longitudinal sectional view showing an example of a silencer according to the present invention.
The interior of the casing 1, in which the front and rear open ends of the cylindrical can body 2 are closed with end plates 3 and 4, includes a first partition plate 5 and a second partition plate 6.
Accordingly, it is divided into a first expansion chamber 1, a second expansion chamber 8, and a resonance chamber 9.

The inlet exhaust conduit 10 inserted into the casing 1 through the end plate 3 further passes through the first partition plate 5 and opens into the second expansion chamber 8 .

The exhaust conduit 10 has a reduced diameter portion 11 with a reduced diameter at the tip,
One end of a porous conduit 12 having a large number of small holes 13, 13 formed around the reduced diameter portion 11 is fitted and fixed.

The other end of the perforated conduit 12 is fitted and fixed in a recess 14 formed in the second partition plate 6, and one or more small holes 15 are opened in this recess 1tK to allow the perforated conduit 12 to be connected to the recess 1tK. The noise is propagated into the resonance chamber 9.

Particularly, according to the present invention, the second partition plate 6 has the small holes 13.
A through hole 6A having a larger diameter than 13 is opened, and a small hole 1 is opened.
Even if the pipes 3 and 13 are clogged, the back pressure of the exhaust system including the porous conduit 12 etc. does not increase and no load is placed on the engine.

That is, the small hole 13 of the through hole 6A has a diameter of 1 to 3, for example.
If the diameter is about 4 to 7 m, one or more of these diameters are opened, but this is because the corrosion mentioned above or the adhesion of carbon etc. gradually grows. However, even if the small holes 13 and 13 are blocked, the diameter of the through hole 6A is increased so that the exhaust gas can be discharged from the small hole 15 through the resonance chamber 9 and from the through hole 6A to the second expansion chamber 8. It is.

Therefore, due to the adhesion and growth of carbon etc., the original through hole 6
A is not completely blocked, but is blown away by the ejection force of exhaust gas in the middle of its growth.

In the figure, reference numeral 16 indicates an outlet side exhaust conduit, and this conduit 16 passes through the end plate 4 and is inserted into the casing 1, and further passes through the second and first partition plates 6 and 5 to enter the first expansion chamber 7. It's open.

1-117.18 are short-circuit holes drilled in the inlet side natural air conduit 10 and the outlet side exhaust conduit 16, respectively, and 19 is the first partition plate 5.
Many small holes were opened in the area.

Next, the effect will be explained.

Exhaust gas sent from the inlet side exhaust pipe 10 passes through the reduced diameter portion 11 at the rear end of the exhaust pipe and is contracted.

This contraction slows down the pulsating exhaust gas flow and regulates the pressure, alleviating the pulsation of the exhaust gas and muffling it.

This exhaust gas then enters the perforated conduit 12 and enters the small hole 13.
It is further diffused into the second expansion chamber 8.

This diffusion also regulates the pressure and muffles the sound in the same way as contracted flow.

In particular, if this diffusion effect is continued for a long time, tar, carbon, rust, etc. in the exhaust gas will grow and try to block the small holes 13, but in the present invention, relatively large diameter through holes 6 are formed in the partition plate 5.
Since A is open, this part will not become clogged even by the growth of carbon or the like.

Therefore, even if the small hole 13 of the porous conduit 12 is blocked, the back pressure in the exhaust system including the porous conduit 12 does not increase due to the presence of the through hole 6A, and no burden is placed on the engine.

According to the experimental results, the performance in terms of sound deadening is 95-99% compared to the one without the through hole 6A, and although there is a slight decrease in performance, the conventional one has the same performance in terms of preventing exhaust pressure from rising. It was much better.

The exhaust gas after this diffusion passes through the small hole 19 of the first partition plate 5 and when flowing into the first expansion chamber 7, it is muffled again in the same manner as described above, but here, the exhaust gas is muffled again in the same manner as described above. A part of the exhaust gas passing therein directly flows into the first expansion chamber 7 through the short-circuit hole 17, preventing the back pressure of the porous conduit 12 from increasing and joining with the exhaust gas that has undergone the rediffusion effect. However, sonic interference occurs between the exhaust gas and the exhaust gas, which also acts as a silencing effect.

The exhaust gas that has been repeatedly muted in this way flows into the outlet side exhaust conduit 16, and further joins with the exhaust gas that has just flown in from the second expansion chamber 8 through the short-circuit hole 18 in this pipe, causing sonic interference. It is discharged after the sound is muffled.

Note that in the above-mentioned muffler, the exhaust gas flowing in through the through hole 15 passes through the chamber 9 and flows out through the through hole 6A, but this chamber 9 acts as a resonance chamber.

In other words, the speed at which exhaust gas flows into the chamber 9 from the vent 15 is approximately 30 rpz/sec, whereas sound waves normally travel at a high speed of 340 ml sec. Even if you try to disturb it, it is impossible.

Therefore, even if exhaust gas flows into this chamber 9, this chamber 9 acts as a resonance chamber and attenuates sound waves of a predetermined frequency.

However, if the opening ratio of the through holes 15 and 6A through which the sound waves flow in with respect to the partition plate 6 (excluding the outlet side exhaust pipe 16) is usually 30% or more, this chamber 9 and the second expansion chamber 8 will be acoustically It can be regarded as one chamber, and care must be taken because sufficient resonance effects cannot be obtained.

In addition, the frequency of the peak level of the noise that is muffled by the resonance chamber 9 (resonance attenuation frequency) is determined not only by the volume of the resonance chamber 9 but also by the area or flow path shape of the through hole 15 between the cylinder 12 and the resonance chamber 9. The dimensions of the perforated conduit 12 should be determined carefully through experiments as they are closely related to each other. Therefore, sufficient consideration should be given to determining this dimension.

As mentioned above, since one or more through holes having a diameter larger than the small hole of the porous conduit are opened in the second partition plate that partitions the resonance chamber and the expansion chamber, the small hole of the conduit is used for exhaust gas. Even if this hole is blocked by carbon in the gas or growth of rust, etc., this hole will not be blocked, and as a result, the back pressure in the exhaust system including this conduit will not increase and have no adverse effect on the engine.

While setting the diameter of the through hole of the housing to a predetermined value,
Since the hole is opened in a part of the pipe, the diffusion silencing effect of exhaust gas does not deteriorate significantly under normal conditions.Furthermore, the simple structure of providing a through hole in the perforated pipe reduces the product cost. Also, even if the button is pressed during assembly, it will not have any adverse effect, resulting in extremely excellent effects.

[Brief explanation of drawings]

The figure is a longitudinal sectional view of a silencer according to the present invention. 1...Casing, 2...Can body, 3,
4... End plate, 5, 6... Partition plate, 6A.
...Throughout, 7,8...Expansion chamber, 9...
... Resonance chamber, 10 ... Inlet side exhaust pipe, 11
...Reduced diameter section, 12... Porous conduit.

Claims (1)

[Scope of utility model registration request] The inside of the casing with both ends closed by end plates is the first
and a second partition plate to form a first expansion chamber, a second expansion chamber, and a resonance chamber, and an inlet conduit extending through the end plate of the casing, passing through the first expansion chamber and entering the second expansion chamber. The outlet side conduit protrudes and extends through the other end plate of the casing, penetrates the resonance chamber and the second expansion chamber, and projects into the first expansion chamber, and a reduced diameter part formed at the insertion tip of the inlet side conduit and the A through hole having a larger diameter than the small hole formed in the porous conduit is provided in a second partition plate that communicates with the resonance hole of the resonance chamber through a porous conduit and partitions the second expansion chamber and the resonance chamber. A silencer.