JP2008274869A - Muffler for automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce aging of sound quality of a muffler of an automobile. <P>SOLUTION: This muffler is provided with a first expansion chamber 3 partitioned by a first bulkhead plate 1 and a second bulkhead plate 2; an outer tube 6 having a second expansion chamber 4 and a resonance chamber 5 formed inside and constructing a main body part of the muffler; an exhaust gas introduction pipe 7 of which one end is used as an introduction port 7a of exhaust gas from the engine and passes through the expansion chamber, of which another end opens in the resonance chamber 5, and which has a plurality of first small holes 7b formed on a circumference surface of a section arranged in the first expansion chamber 3; and an exhaust gas discharge pipe 8 of which one end opens in the second expansion chamber 4 and passes through the resonance chamber 5 and of which another end opens at an outside of the outer tube 6 and is used as an exhaust gas discharge port 8a. The exhaust gas discharge pipe 8 is provided with an inner tube of which one end opens in the second expansion chamber 4, of which another end is used as a discharge port 8a, and which has a plurality of second small holes 9b formed on a circumference surface; and an outer tube 10 covering an outer circumference of the inner tube 9 with keeping a gap and having the gap with the inner tube 9 blocked at both ends. Glass wool G is filled in the gap between the inner tube 9 and the outer tube 10. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an automobile silencer that exhausts and silences exhaust gas from an automobile engine.

  Conventionally, various types of silencers for automobiles have been developed and put into practical use. For example, Patent Document 1 proposes an automobile muffler that has an outer cylinder with a three-chamber partition structure and is filled with glass wool (glass short fiber) as a silencer in a central silencer chamber. That is, this automobile muffler includes an outer pipe having two resonance cavities and a muffler chamber disposed between the resonance cavities, and exhaust pipes arranged in three rows on the outer pipe. ing.

  Each of these exhaust pipes is a punching pipe in which a large number of small holes are formed in the peripheral surface, and is installed in a state of penetrating through a silencer chamber filled with glass wool throughout the room. With this configuration, when exhaust gas is introduced into the muffler chamber from many small holes in the exhaust pipe, the exhaust noise is muffled by the glass wool in the chamber. The small hole in the exhaust pipe has an inner diameter of about 2 to 3 mm.

Japanese Utility Model Publication No. 7-20330

The following problems remain in the conventional technology.
Conventionally, glass wool has been filled in the silencer chamber as a silencer. However, when water accumulates in the silencer chamber, there is a disadvantage in that the silencing effect is reduced and the sound volume increases over time.
In addition, since exhaust from the exhaust pipe directly hits the outer cylinder, only that part may become high temperature and may be oxidized and discolored. For this reason, there has been a disadvantage that the portion exposed to the exhaust gas is easily corroded.
Furthermore, in silencers that do not use glass wool, exhaust is performed through a large number of small holes in the punching pipe, and the exhaust is expanded and rectified. In this case, since the exhaust gas flow rate is large, a large air flow noise is generated when the exhaust gas passes through a small hole in the punching pipe. As a countermeasure, if the hole diameter is reduced, exhaust resistance is generated, and there is a problem that the output in the high engine speed range is reduced.

  The present invention has been made in view of the above-described problems, and is intended to reduce the secular change in volume, further suppress oxidation of the outer cylinder due to exhaust, and achieve both noise reduction and output improvement of a large displacement vehicle. An object is to provide a muffler for automobiles that makes it possible.

  The present invention employs the following configuration in order to solve the above problems. That is, the automobile silencer of the present invention includes an expansion chamber and a resonance chamber, which are partitioned by a partition plate, formed inside and constituting a main part of the silencer, and one end of which is an inlet for exhaust gas from the engine. An exhaust introduction pipe having a plurality of first small holes formed in a peripheral surface of a portion disposed through the expansion chamber and having the other end opened in the resonance chamber and disposed in the expansion chamber; An exhaust discharge pipe that is opened into the expansion chamber, penetrates the resonance chamber, and has the other end opened to the outside of the outer cylinder. The exhaust discharge pipe has one end of the exhaust discharge pipe. An inner tube having an opening in the expansion chamber and having the other end serving as the discharge port and a plurality of second small holes formed in the peripheral surface, and covering the outer periphery of the inner tube with a gap, the inner tube at both ends And an outer tube whose gap is closed, and a silencer is filled between the inner tube and the outer tube. And wherein the are.

  In this automobile silencer, the exhaust discharge pipe arranged in the outer cylinder is filled with a silencer between the inner pipe and the outer pipe of the double pipe structure. There is no need to fill the material, the amount of the sound-absorbing material used can be reduced as much as possible, and the aging of the increase in sound volume due to the accumulation of water can be suppressed because the sound-absorbing material dries quickly.

  The silencer for automobiles according to the present invention is characterized in that the exhaust introduction pipe is arranged with the other end bent so that the other end opens toward the outer peripheral surface of the exhaust discharge pipe. That is, in this muffler for automobiles, the other end of the exhaust introduction pipe is bent so as to open toward the outer peripheral surface of the exhaust discharge pipe, so that the exhaust does not directly hit the inner wall of the outer cylinder, Oxidation and discoloration can be prevented. In addition, since high-temperature exhaust hits the outer peripheral surface of the exhaust discharge pipe, the sound-absorbing material such as glass wool in the exhaust discharge pipe is warmed and dried, so that it is possible to further suppress the secular change in volume due to water. Further, since the exhaust gas hits the outer peripheral surface of the exhaust discharge pipe which is a curved surface and is diffused, the exhaust sound is also scattered and a silencing effect can be obtained.

  Furthermore, the automobile silencer of the present invention is characterized in that the other end of the exhaust introduction pipe is opened obliquely with respect to the axis. That is, in this automobile muffler, the other end of the exhaust introduction pipe is cut obliquely with respect to the axis and opened, so that the opening area gradually increases with respect to the flow of exhaust, and the exhaust is accordingly adjusted. Since it gradually diffuses, a silencing effect can be obtained.

  In the automobile silencer of the present invention, the expansion chamber and the resonance chamber are partitioned by a first partition plate, and the expansion chamber is located upstream of the exhaust gas from the region where the first small hole is formed. A second expansion chamber which is partitioned by a second partition plate provided on the side and in which the first small hole forming region is disposed and an opening at one end of the exhaust discharge pipe is disposed A first through hole is formed in the first partition plate, and a second through hole is formed in the second partition plate. That is, in this silencer for automobiles, the first through hole is formed in the first partition plate, and the second through hole is formed in the second partition plate. Exhaust gas to one expansion chamber and the resonance chamber moves to another expansion chamber or resonance chamber via the first through hole and the second through hole. At this time, the first through-hole functions as a balance hole that restricts and suppresses the inflow of exhaust gas from the resonance chamber to the first expansion chamber. Therefore, the pressure in the first expansion chamber, the second expansion chamber, and the resonance chamber can be adjusted by adjusting the hole diameters of the first through hole and the second through hole. Can be reduced to suppress pressure fluctuations.

  Moreover, the silencer for automobiles of the present invention is characterized in that an inner diameter of the first small hole is 10 mm. That is, in this muffler for automobiles, the first small hole is set to an inner diameter of 10 mm, which is significantly larger than the hole diameter of the conventional punching pipe, so that it contracts when exhaust passes through the first small hole. The increase in the flow velocity due to the airflow is suppressed, and the airflow noise can be reduced. Further, since the exhaust resistance increases in proportion to the square of the exhaust flow velocity, the output can be improved even in a high rotation range as compared with the case of using a conventional punching pipe. Therefore, it is possible to achieve both noise reduction and output improvement in a large displacement vehicle having a displacement of 2.5 liters or more.

The present invention has the following effects.
In other words, according to the automobile silencer according to the present invention, the exhaust discharge pipe disposed in the outer cylinder is filled with the silencer between the inner pipe and the outer pipe of the double pipe structure. The amount of the material used can be reduced as much as possible, and the secular change of the volume increase due to the accumulation of water can be suppressed. Furthermore, by bending the other end of the exhaust pipe so that it opens toward the outer peripheral surface of the exhaust pipe, it is possible to prevent oxidation and discoloration of the outer cylinder due to burning, and to dry the sound deadening material in the exhaust pipe. Thus, the secular change can be further suppressed. Accordingly, it is possible to obtain a high-quality automobile silencer that can suppress a secular change in volume and obtain a high silencing effect over a long period of time.

  Hereinafter, an embodiment of an automobile silencer according to the present invention will be described with reference to FIGS. 1 and 2. In each drawing used in the following description, the scale is appropriately changed to make each member a recognizable size.

  The automobile silencer of this embodiment is a muffler silencer connected to an engine for a large displacement vehicle having a displacement of 2.5 liters or more, for example, as shown in FIG. 1 and FIG. The first expansion chamber 3, the second expansion chamber 4, and the resonance chamber 5 partitioned by the first partition plate 1 and the second partition plate 2 are formed inside to constitute a main part of the silencer. The cylinder 6 and an exhaust introduction pipe 7 having one end serving as an exhaust gas introduction port 7a from the engine and penetrating the first expansion chamber 3 and the second expansion chamber 4 and opening the other end into the resonance chamber 5. And an exhaust discharge pipe 8 having one end opened in the second expansion chamber 4 and penetrating the resonance chamber 5 and the other end opened to the outside of the outer cylinder 6 as an exhaust gas discharge port 8a. .

Both ends of the outer cylinder 6 are closed by outer baffles 6a and 6b, and the inlet 7a of the exhaust inlet pipe 7 and the outlet 8a of the exhaust outlet pipe 8 protrude outward from the outer baffles 6a and 6b.
The exhaust introduction pipe 7 has a large number of first small holes 7b formed only on the peripheral surface of the portion arranged in the first expansion chamber 3, and the peripheral surfaces of the other portions are non-porous.
In addition, the exhaust introduction pipe 7 is a bend pipe which is disposed in the resonance chamber 5 with the other end 7c bent so that the other end opens toward the outer peripheral surface of the exhaust discharge pipe 8.
Further, the other end of the exhaust introduction pipe 7 is opened obliquely with respect to the axis. That is, the exhaust introduction pipe 7 has the other end opening 7d cut obliquely.

  The exhaust discharge pipe 8 includes an inner pipe 9 having one end opened in the first expansion chamber 3 and the other end serving as a discharge port 8a, and a plurality of second small holes 9b formed on the peripheral surface, The outer tube 10 is provided with an outer tube 10 that covers the outer periphery of the inner tube 9 with a gap therebetween and that is closed at both ends with the inner tube 9. And between the inner tube | pipe 9 and the outer tube | pipe 10, glass wool G is filled as a silencer (sound absorbing material).

The first extension chamber 3 and the resonance chamber 5 are partitioned by the first partition plate 1, and the first extension chamber 3 and the second extension chamber 4 are partitioned by the second partition plate 2. ing. The second partition plate 2 is provided on the upstream side of the exhaust gas from the formation region of the first small hole 7b. That is, the first expansion chamber 3 is provided with a formation region of the first small hole 7b. The second expansion chamber 4 has an opening at one end of the exhaust discharge pipe 8.
The inner diameter of the first small hole 7b is 10 mmφ.

Further, the first partition plate 1 is formed with a first through hole 1a, and the second partition plate 2 is formed with a second through hole 2a to form the second through hole 2a. The expansion chamber communication pipe 11 is fixed to the insertion state. The expansion chamber communication pipe 11, the exhaust introduction pipe 7 and the exhaust discharge pipe 8 are arranged in parallel with each other.
The outer cylinder 6, the exhaust introduction pipe 7, and the exhaust discharge pipe 8 are all formed of a metal plate such as stainless steel or titanium alloy.

  In this automobile silencer, exhaust gas is circulated as follows, and the sound is silenced and exhausted. In the figure, the flow direction (exhaust path) of the exhaust gas is indicated by an arrow.

  First, exhaust gas from the engine is introduced into the pipe through the introduction port 7a of the exhaust introduction pipe 7, and flows into the first expansion chamber 3 from a large number of first small holes 7b, and a part thereof is opened at the other end. It flows into the resonance chamber 5 from the part 7d. The exhaust gas that has flowed into the first expansion chamber 3 flows into the second expansion chamber 4 via the expansion chamber communication pipe 11. On the other hand, the exhaust gas ejected from the other end opening 7 d of the exhaust introduction pipe 7 is blown to the outer peripheral surface of the exhaust discharge pipe 8 in the resonance chamber 5. In addition, by introducing the exhaust gas into the resonance chamber 5, an exhaust sound silencing effect can be obtained by resonance and resonance action.

  A part of the exhaust gas in the first expansion chamber 3 flows into the resonance chamber 5 when the internal pressure of the first expansion chamber 3 is higher than that of the resonance chamber 5. Further, when the internal pressure of the resonance chamber 5 is higher than that of the first expansion chamber 3, the exhaust gas flows from the resonance chamber 5 into the first expansion chamber 3. That is, the flow direction of the exhaust gas through the first through hole 1 a is set according to the pressure difference between the first expansion chamber 3 and the resonance chamber 5. The first through hole 1 a has a function as a balance hole that restricts and suppresses the inflow of exhaust gas from the resonance chamber 5 to the first expansion chamber 3.

  The exhaust gas that has flowed into the second expansion chamber 4 flows into the inner tube 9 from one end side of the exhaust discharge pipe 8, flows through the inner tube 9 and the outer tube 10, and discharge port 8a on the other end side. To the outside. During this distribution, the exhaust gas in the inner tube 9 circulates while being dispersed into the glass wool G filled between the inner tube 9 and the outer tube 10 through a number of second small holes 9b. Is done. That is, the exhaust discharge pipe 8 functions as an internal silencer.

  As described above, the automobile silencer of the present embodiment is filled with the glass wool G between the inner tube 9 and the outer tube 10 of the double tube structure in the exhaust discharge pipe 8 arranged in the outer cylinder 6. Therefore, there is no need to fill the expansion room with glass wool G, the amount of glass wool G used can be reduced as much as possible, and the glass wool G can be dried quickly, thereby suppressing the secular change of volume increase due to water accumulation. it can.

  Further, since the other end portion 7 c of the exhaust introduction pipe 7 is bent so as to open the other end opening portion 7 d toward the outer peripheral surface of the exhaust discharge pipe 8, the exhaust gas is directly applied to the outer baffle 6 b of the outer cylinder 6. Therefore, oxidation and discoloration of the outer cylinder 6 due to burning can be prevented. That is, it is possible to suppress color unevenness due to burning that impairs aesthetics, and to improve corrosion resistance. Further, since the high temperature exhaust gas hits the outer peripheral surface of the exhaust discharge pipe 8, the glass wool G in the exhaust discharge pipe 8 is warmed and dried, so that the secular change in volume due to water can be further suppressed. Further, since the exhaust gas hits the outer peripheral surface of the exhaust discharge pipe 8 which is a curved surface and is diffused, the exhaust sound is also scattered and a silencing effect can be obtained.

Further, since the other end opening 7d of the exhaust introduction pipe 7 is cut and opened obliquely with respect to the axis, the opening area gradually increases with respect to the exhaust flow, and the exhaust gradually increases accordingly. Since it diffuses, a silencing effect can be obtained.
Furthermore, by adjusting the hole diameters of the first through-hole 1a and the second through-hole 2a, the pressure in the first expansion chamber 3, the second expansion chamber 4, and the resonance chamber 5 can be adjusted. A pressure difference due to exhaust pulsation can be reduced to suppress pressure fluctuation.

  In addition, since the first small hole 7b is set to an inner diameter of 10 mm, which is significantly larger than the hole diameter of the conventional punching pipe, an increase in flow rate due to contraction occurs when the exhaust gas passes through the first small hole 7b. It is suppressed and airflow noise can be reduced. Further, since the exhaust resistance increases in proportion to the square of the exhaust flow velocity, the output can be improved even in a high rotation range as compared with the case of using a conventional punching pipe. Therefore, it is possible to achieve both noise reduction and output improvement in a large displacement vehicle having a displacement of 2.5 liters or more.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

It is a simple sectional view showing a silencer for cars of one embodiment concerning the present invention. In this embodiment, it is the side view which fractured | ruptured a part which shows an exhaust discharge pipe.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... 1st partition plate, 1a ... 1st through-hole, 2 ... 2nd partition plate, 2a ... 2nd through-hole, 3 ... 1st expansion chamber, 4 ... 2nd expansion chamber, 5 ... Resonance chamber, 6 ... outer cylinder, 7 ... exhaust introduction pipe, 7a ... introduction port, 7b ... first small hole, 8 ... exhaust discharge pipe, 8a ... discharge port, 9b ... second small hole, 9 ... inner pipe 10 ... Outer pipe, 11 ... Expansion room communication pipe, G ... Glass wool (silencer)

Claims (5)

An outer cylinder that is formed inside with an expansion chamber and a resonance chamber partitioned by a partition plate and constitutes a main part of the silencer;
One end is an exhaust gas introduction port from the engine, passes through the expansion chamber, the other end is opened in the resonance chamber, and a plurality of first small holes are formed in the peripheral surface of the portion disposed in the expansion chamber An exhaust introduction pipe formed with,
An exhaust discharge pipe having one end opened into the expansion chamber and penetrating the resonance chamber and the other end opened to the outside of the outer cylinder;
The exhaust discharge pipe, an inner pipe having one end opened in the expansion chamber and the other end serving as the discharge port, and a plurality of second small holes formed in the peripheral surface;
An outer tube that covers the outer periphery of the inner tube with a gap therebetween and the gap between the inner tube and the inner tube is closed at both ends;
A silencer for automobiles, wherein a silencer is filled between the inner tube and the outer tube. The muffler for automobiles according to claim 1,
The muffler for automobiles, wherein the exhaust introduction pipe is arranged with the other end bent so that the other end opens toward the outer peripheral surface of the exhaust discharge pipe. The muffler for automobiles according to claim 2,
A muffler for automobiles, wherein the other end of the exhaust pipe is opened obliquely with respect to the axis. The muffler for automobiles according to any one of claims 1 to 3,
The expansion chamber and the resonance chamber are partitioned by a first partition plate,
The expansion chamber is partitioned by a second partition plate provided on the upstream side of the exhaust gas from the first small hole forming region, and the first small hole forming region is disposed. An extension chamber and a second extension chamber in which an opening at one end of the exhaust discharge pipe is arranged,
A muffler for automobiles, wherein a first through hole is formed in the first partition plate, and a second through hole is formed in the second partition plate. The silencer for automobiles according to any one of claims 1 to 4,
A muffler for automobiles, wherein the inner diameter of the first small hole is 10 mm.

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