JPH02136506A - Muffler - Google Patents

Abstract

PURPOSE:To prevent generation of resonance phenomenon by extendingly arranging an introduced extending pipe and a tail extending pipe extending in a muffler main body and each one part of which is a double tube on an exhaust conduit and a tail pipe respectively, in the muffler in which plural chambers partitioned by a bulkhead are communicated to each other through a short pipe. CONSTITUTION:The inside of a muffler body 1 connected to the exhaust conduit 2 of an engine is partitioned in plural chambers by a bulkhead 4 and respective chambers are communicated to each other by a short pipe 10 penetrating the bulkhead 4. An introduced extending pipe 16' extending from the exhaust conduit 2 to the inside of the muffler main body 1 is arranged and also a tail extending pipe 16 extending from a tail pipe 3 to the inside of the muffler main body 1 is arranged in such a muffler. Respective extending pipe 16, 16' are constructed in such processes that double pipes consisting of outer pipes 6, 12, inner pipes 7, 13 and single pipes 5, 11 communicating thereto are provided and resistance bodies 9, 15 are filled in the spaces between the inner and outer pipes 7, 6 and 13, 12 respectively. Introducing ports 8, 8' and 14, 14' are arranged respectively on both ends of the upper and lower stream of respective inner pipes 7, 13.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a muffler for muffling exhaust noise generated from automobile engines, etc., and in particular to a muffler that has low resistance to the flow of exhaust gas and can muffle extremely effectively. It is related to vessels.

[Prior Art] There have been various types of silencers for muffling the exhaust noise generated from automobile engines, etc., and a typical one is a cylindrical silencer as shown in Figure 3. An exhaust pipe 2 is attached to one end of the muffler body 1 and a tail pipe 3 is attached to the other end, and the inside of the muffler body 1 is divided into a plurality of chambers by a partition plate 4, and a short pipe 10 passing through the partition plate 4 Each chamber is communicated with each other, and an introduction extension pipe 17 extends from the exhaust pipe 2 into the muffler main body 1, and a tail extension pipe 17'' extends from the tail pipe 3 into the muffler main body 1. Ta.

[Problems to be Solved by the Invention] However, in this case, if the diameters of the introduction extension pipe 17, short pipe 10, and tail extension pipe 17' are made smaller to increase the flow velocity of the exhaust gas, the exhaust resistance to the flow of the exhaust gas is increased. becomes larger, negatively impacting engine power and fuel consumption,
Furthermore, it was inevitable that fluid noise would be generated due to the high-speed flow of exhaust gas.

On the other hand, the introduction extension pipe 17, the short pipe 10 and the tail extension pipe 1
If the diameter of 7' is increased, the damping that suppresses the occurrence of resonance becomes smaller.
In addition, resonance occurred in the tail pipe 3 including the tail extension pipe 17', resulting in a reduction in the silencing performance.

The purpose of this invention is to eliminate the above-mentioned drawbacks of the muffler.It is a compact muffler that does not cause resonance even if the diameters of the inlet extension tube, tail extension tube, and short tube are large, can effectively muffle noise, and are compact. Furthermore, the present invention aims to provide a novel muffler that does not adversely affect engine output or fuel consumption.

[Means for Solving the Problems] This invention comprises an exhaust pipe connected to an engine and introducing exhaust gas from the engine, a muffler main body communicating with the exhaust pipe, and a tail pipe continuous with the muffler main body. ,
In a muffler that has a muffler main body divided into a plurality of chambers by a partition plate and a short pipe that communicates each chamber, an introduction/extension pipe extending from the exhaust conduit into the muffler main body and/or a tail pipe extending from the muffler main body Tail extension tube or outer tube extending inward,
A silencer is composed of a double pipe consisting of an inner pipe having an inlet at an upstream end and a downstream end, and a resistor filled between the outer pipe and the inner pipe, and a single pipe with a single layer structure communicating with the double pipe. It consists of an exhaust pipe that is connected to the engine and introduces exhaust gas from the engine, a muffler main body that communicates with the exhaust pipe, and a tail pipe that is connected to the muffler main body, and there is a partition inside the muffler main body. divided into multiple rooms by
In a silencer having a short pipe that communicates each chamber, an introduction extension pipe extending from the exhaust conduit into the inside of the muffler main body and/or a tail extension pipe extending from the tail pipe into the inside of the muffler main body are connected to the outer pipe, the upstream end or the downstream end. The above problem is solved by constructing a silencer from a double tube consisting of an inner tube having an inlet at the end and a resistor filled between the outer tube and the inner tube. .

[Function] Resonance occurs when, for example, sound waves generated by an engine propagate through the gas in the exhaust pipe, and are reflected at the tip of the inlet extension pipe, which is considered to be an open end, and become a reflected wave that interferes with the next sound wave and generates energy. This is a phenomenon that occurs when In order to avoid the accumulation of energy due to resonance, it is sufficient to provide resistance in the gas flow path, but as described above, the exhaust resistance becomes large. In the present invention, the energy of sound waves is absorbed by a resistor provided between an inner tube and an outer tube of a double tube structure. The sound waves generated by the engine propagate through the exhaust gas in the exhaust conduit, are introduced into the resistor through an inlet at the upstream and/or downstream end of the inner pipe, and are absorbed by the resistor. It is extremely important that the inner tube has no holes other than the inlet for guiding sound waves to the resistor.

In other words, if the inner tube has holes, the pressure of the sound waves in the space between the inner tube and the outer tube and the space inside the inner tube will be the same, so the sound waves will be attenuated by the resistor. This is because there is no

In addition, in order for sound waves to be attenuated by the resistor, the space between the inner tube and the outer tube must be isolated from the space inside the inner tube, and the length of the part of the inner tube without holes or the sound wave 16 wavelengths
More than 1/8, preferably more than 1/8, is required, and practically more than ioam is required.

[Embodiment] Fig. 1 shows a first embodiment of the present invention, in which a muffler main body 1 is connected to an exhaust pipe 2 connected to an exhaust manifold (not shown) of an engine, and a tail pipe 3 is connected from the muffler main body 1 to a tail pipe 3. It is connected. The inside of the muffler body 1 is divided into a plurality of chambers by a partition plate 4, and a short pipe l passes through the partition plate 4.
Each chamber is communicated with each other by O.

An extension pipe 16 is introduced into the silencer main body 1 from the exhaust pipe 2.
A tail extension pipe 16' extends from the tail pipe 3 into the interior of the muffler main body 1.

The introduction extension tube 16 is composed of a double tube consisting of an outer tube 6 and an inner tube 7, and a single tube V5 of a single tube structure communicating with the double tube.
The space between the outer tube 6 and the inner tube 7 is uniformly filled with sales antibody 9.

Similarly, the tail extension tube 16' is connected to the outer tube 12 and the η tube 13.
A double pipe consisting of a double pipe and a single pipe 11 having a single pipe structure communicating with the double pipe.
Similarly, resistors 15 are uniformly filled in the space between the outer tube 12 and the inner tube 13.

Furthermore, an upstream inlet 8 is provided at the upstream end of the inner tube 7, and a downstream inlet 8' is provided at the downstream surface. 14 ports are provided respectively.

The resistor 9 may be any material as long as it absorbs sound waves, and may be a fibrous material, a wire-like material, a wire mesh, a granular material, a multi-perforated plate, or the like.

Note that there is an optimal resistance value for sound waves, and if the resistance value is too large and the sound is absorbed too rapidly, it will be similar to a state where the double pipe section is blocked, and the effect will be small.
On the other hand, if the resistance value is too small, sound absorption will not be sufficient.

Further, it is desirable that sound absorption be carried out by fully utilizing the length of the double pipe section.

To this end, the length of the portion of the inner tube 7 or 13 without holes must be at least 1/16 of the wavelength, preferably at least 1/8 of the wavelength. In other words, the length of the unperforated portion of the inner tube 7 or 13 is determined by the difference in radius between the outer tube 6 and the inner tube 7 or the outer tube 12 and the inner tube 13.
It is necessary to have a radius difference of at least 5 to 6 times the thickness of the resistor.

In addition, the tips of the single pipes 5 and 11 of the double pipe structure are open to each chamber of the muffler main body 1, so the sound pressure is always low, and the downstream inlet 8' of the inlet extension pipe 16 and the tail extension pipe This prevents the sound pressure at the upstream introduction port 14' of the resistor 16' from decreasing and preventing sound waves from being introduced into the resistor. If the single tubes 5 and 11 were not present, the downstream inlet 8' and the upstream inlet 14' would be directly open to each chamber, so the sound pressure would be low and no sound waves would be introduced into the resistor.

Therefore, the length of the single tubes 5 and 11 is 1 of the wavelength of the sound wave.
One-sixth or more, preferably one-eighth or more is required.

FIG. 2 shows a second embodiment of the present invention, in which the introduction extension pipe 16 and the tail extension pipe 16' are composed only of a double pipe structure, and the introduction extension pipe 16 has an upstream introduction port 8. The tail extension tube 16' has only a downstream inlet 14 and no upstream inlet.

This second embodiment has the advantage that it is possible to lengthen the portions of the inner tubes 7 and 13 without holes, and that it is possible to muffle low-frequency sounds. however.

Since there is only one introduction port for the sound waves, there is also the drawback that the sound waves are difficult to introduce into the resistor. Incidentally, since the upstream inlet 8 and the downstream inlet 14 are not open to each chamber of the muffler main body l, a single pipe is not necessary.

[Effects of the Invention] The silencer according to the present invention has the configuration as described above, has low exhaust resistance to the flow of exhaust gas, does not have a negative effect on engine output and fuel consumption, and does not cause resonance phenomena. It has the effect of efficiently muffling noise without generating any noise, making it ideal as a muffler for automobile engines, etc. In addition, it is compact and simple in structure, has enough durability to withstand use under severe conditions, and is extremely excellent in practical use.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a first embodiment of a silencer according to the present invention, FIG. 2 is a longitudinal sectional view of a second embodiment, and FIG. 3 is a longitudinal sectional view of a conventional example. l... Silencer body, 2... Exhaust pipe, 3... Tail pipe, 4... Partition plate, 5... Single pipe, 6... Outer pipe, 7
...Inner pipe, 8...Upstream inlet, 9...Resistor, 1
0...Short tube, 11...Single tube, 12...Outer tube, 13
...Inner pipe, 14...Downstream inlet, 15...Resistor, 16...Introduction extension tube.

Claims (2)

[Claims] (1) An exhaust pipe connected to the engine and introducing exhaust gas from the engine, a muffler body communicating with the exhaust pipe,
and a tail pipe connected to the muffler main body, the muffler main body is divided into a plurality of chambers by a partition plate, and the muffler has a short pipe that communicates each chamber, an introduction extending from the exhaust conduit to the inside of the muffler main body. An extension tube and/or a tail extension tube extending from the tail tube into the muffler main body is an outer tube, an inner tube having an inlet at an upstream end and a downstream end, and a resistor filled between the outer tube and the inner tube. 1. A silencer characterized by comprising a double tube consisting of a body and a single tube having a single layer structure communicating with the double tube. (2) an exhaust pipe connected to the engine and introducing exhaust gas from the engine; a muffler body communicating with the exhaust pipe;
and a tail pipe connected to the muffler main body, the muffler main body is divided into a plurality of chambers by a partition plate, and the muffler has a short pipe that communicates each chamber, an introduction extending from the exhaust conduit to the inside of the muffler main body. An extension tube and/or a tail extension tube extending from the tail tube into the silencer main body is an outer tube, an inner tube having an inlet at an upstream end or a downstream end, and a resistor filled between the outer tube and the inner tube. A silencer characterized by being constructed of a double tube consisting of a body and a body.