JP2009068401A - Exhaust muffler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust muffler capable of suitably inhibiting generation of resonance noise in a wide range of engine operation conditions. <P>SOLUTION: A tapered part 320 of which diameter is reduced to an exhaust gas downstream side is provided in the middle of a third exhaust pipe 30. A hole 330 for keeping communication between an inside of a resonance chamber 340 and an inside of the third exhaust pipe 30 is provided at a wall surface of an end part of the third exhaust pipe 30 connected to a large diameter side of the tapered part 320. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an exhaust silencer that reduces exhaust noise of an internal combustion engine.

  An exhaust system of the internal combustion engine is provided with a silencer whose internal space functions as an exhaust silencer chamber. In such a silencer, as shown in FIG. 12, a silencer structure is formed by communicating the inside of the exhaust pipe with the inside of the silencer chamber through a hole provided in the wall surface of the exhaust pipe. There is something.

In addition, as a prior art document concerning this invention, the following patent documents 1-6 are mentioned.
JP 2005-256688 A JP 2005-256644 A Japanese Patent Laid-Open No. 11-117724 Japanese Patent Laid-Open No. 9-324619 JP 2002-303117 A JP-A-7-133712

  By the way, when the exhaust gas flows through the exhaust pipe, a vortex flow of the exhaust gas is generated at the hole forming portion. This vortex flow stays at a substantially constant position without being peeled off from the hole formation site when the exhaust flow rate is low. However, when the exhaust gas flow rate becomes high, the vortex flow comes off from the hole formation site. Thus, when the vortex flow of the exhaust gas comes off from the hole formation site, a pressure wave that periodically changes is generated in the vicinity of the hole, and the fluctuation frequency of the pressure wave is caused by the exhaust system. When the resonance frequency coincides with the resonance frequency of the reflection of the wall surface or the like, a loud resonance sound such as a whistling sound is generated from the exhaust system.

  Here, since the fluctuation frequency of the pressure wave can be changed by changing the shape of the hole or the peripheral edge of the hole, the fluctuation frequency is changed and the fluctuation frequency is shifted from the resonance frequency. It is possible to suppress the generation of resonance sound. However, in the exhaust system of an internal combustion engine, since the temperature, pressure, and the like change variously, the above-described resonance frequency also changes variously. Therefore, by changing the fluctuating frequency, it is possible to suppress the generation of resonance sound in a certain engine operation state, but newly generate resonance sound in another engine operation state. Thus, with the conventional structure, it is difficult to suppress the generation of resonance noise in a wide range of engine operating conditions.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an exhaust silencer capable of suitably suppressing the generation of resonance noise in a wide range of engine operating conditions.

The means for achieving the above object and the effects thereof will be described below.
The invention according to claim 1 is the exhaust silencer in which the silencer chamber and the exhaust pipe communicate with each other through a hole provided in the wall surface of the exhaust pipe, and a tapered portion is provided in the middle of the exhaust pipe. The gist is that the hole is provided in one of the wall surface of the end of the exhaust pipe and the wall surface of the taper portion connected to the large diameter side of the taper portion.

  As is well known, there is a so-called boundary layer in the vicinity of the surface of the object through which the fluid flows, where the velocity of the fluid is reduced due to the remarkable influence of the viscosity of the fluid. Such a boundary layer is also present on the inner wall of the exhaust pipe through which the exhaust flows. In the boundary layer, the flow velocity of the exhaust gas becomes slower as the inner wall is approached. In addition, the boundary layer becomes thinner as the exhaust flow rate increases.

  Here, in the same configuration, the flow passage cross-sectional area of the exhaust gas is changed by the tapered portion provided in the exhaust pipe, so that the inner wall of the tapered portion and the vicinity of the end portion of the exhaust pipe connected to the large diameter side of the tapered portion are provided. On the inner wall, a boundary layer develops. Therefore, even in a situation where the boundary layer is thinned by increasing the flow velocity of the exhaust, the inner wall of the tapered portion and the inner wall near the end of the exhaust pipe connected to the large diameter side are thicker than other portions. Is formed. Then, by providing the hole on the wall surface on which such a thick boundary layer is formed, that is, the wall surface where the flow rate of exhaust gas is relatively slow, peeling of the vortex generated at the hole formation site is suppressed. As described above, according to this configuration, since the vortex flow generated at the hole forming portion can be suppressed, the fluctuation of the pressure wave, which is the cause of the resonance sound, is less likely to occur. Therefore, even if the engine operating state changes variously, it is difficult for resonance sound to be generated, and generation of resonance noise can be suitably suppressed in a wide range of engine operation states.

  Note that the resonance generated by the conventional silencer as shown in FIG. 12 can be suppressed by further providing a silencer for reducing the resonance. However, in this case, since another silencer is required to provide one silencer, the arrangement space of the silencer becomes large. For this reason, such a plurality of silencers cannot be provided at a portion where a space for arranging the silencer cannot be increased, such as at the end of the exhaust system. However, since the exhaust silencer having the same configuration can suppress the generation of resonance as described above, it is not necessary to further provide a silencer that reduces the resonance, unlike the conventional silencer. For this reason, it is possible to install the silencer in a region where the installation space of the silencer cannot be increased.

  Incidentally, in the same configuration, the “end portion of the exhaust pipe” is a portion in the vicinity of the end portion where a boundary layer thicker than other portions is formed by being connected to the larger diameter side of the tapered portion, and not necessarily It is not limited to the extreme end of the exhaust pipe.

The gist of the invention according to claim 2 is that, in the exhaust silencer according to claim 1, the diameter of the tapered portion is reduced toward the exhaust downstream side.
According to this configuration, due to an increase in exhaust resistance due to the tapered portion, the flow rate of the exhaust gas near the end of the exhaust pipe connected to the tapered portion or the upstream side of the tapered portion, that is, the large diameter side of the tapered portion is slow. Become. For this reason, it is possible to favorably promote the development of the boundary layer at a site where the flow velocity of the exhaust gas decreases.

The gist of the invention according to claim 3 is that, in the exhaust silencer according to claim 1, the diameter of the tapered portion is expanded toward the exhaust downstream side.
According to the same configuration, when exhaust flows from the exhaust pipe connected to the small diameter side of the taper portion toward the taper portion, the flow of the exhaust gas is easily separated from the wall surface at the small diameter portion of the taper portion. In addition, the flow velocity of the exhaust gas in the vicinity of the end of the exhaust pipe connected to the exhaust downstream side of the tapered portion, that is, the large diameter side of the tapered portion becomes slow. For this reason, it is possible to favorably promote the development of the boundary layer at a site where the flow velocity of the exhaust gas decreases.

  In addition, as the structure of the exhaust silencer, as in the invention according to claim 4, the silencer chamber and the exhaust pipe are in direct communication with each other through the hole, or the invention according to claim 5. According to the present invention, a resonance tube is provided in the silencer chamber, and one end of the resonance tube is connected to the hole. Examples include a pipe provided with one end of a side branch type silencer connected to the hole.

Hereinafter, an embodiment embodying an exhaust silencer according to the present invention will be described with reference to FIGS.
FIG. 1 shows the overall configuration of an exhaust system of an internal combustion engine in which an exhaust silencer according to this embodiment is provided.

  As shown in FIG. 1, the exhaust system is provided with a first exhaust pipe 10 connected to an exhaust manifold of an internal combustion engine and provided with a catalytic converter 11 in the middle thereof. A first silencer 100 is connected to the exhaust downstream side. A second exhaust pipe 20 is connected to the exhaust downstream side of the first silencer 100, and a second silencer 200 is connected to the exhaust downstream side of the second exhaust pipe 20. The third exhaust pipe 30 is connected to the exhaust downstream side of the second silencer 200, and the end of the third exhaust pipe 30 on the exhaust downstream side is open to the atmosphere.

The first silencer 100 and the second silencer 200 are exhaust silencers having a known structure, and various silencers for reducing exhaust noise are formed therein.
A third silencer 300 that is an exhaust silencer according to the present invention is provided in the middle of the third exhaust pipe 30.

  FIG. 2 shows a cross-sectional structure of the third silencer 300. As shown in FIG. 2, the third silencer 300 includes an outer cylinder 310 that covers the outer periphery of the third exhaust pipe 30, a tapered portion 320 provided in the middle of the third exhaust pipe 30, and the third exhaust pipe 30. And a hole 330 provided in the wall surface.

A space is provided between the inner peripheral surface of the outer cylinder 310 and the outer peripheral surface of the third exhaust pipe 30, and a resonance chamber 340 is formed by this space.
The diameter of the tapered portion 320 is reduced toward the exhaust downstream side, and the wall surface of the end portion of the third exhaust pipe 30 connected to the large diameter side of the tapered portion 320 (the portion opened to the upstream side of the exhaust) The hole 330 is provided. The inside of the third exhaust pipe 30 and the inside of the resonance chamber 340 communicate with each other through the hole 330. More specifically, the resonance chamber 340 communicates only with the inside of the third exhaust pipe 30, and further communicates with the inside of the third exhaust pipe 30 only through one hole 330. And the exhaust noise of a specific frequency is reduced by the resonator comprised with the hole 330 and the resonance chamber 340. FIG. The diameter of the third exhaust pipe 30 connected to the small diameter side of the taper portion 320 (the portion opened to the downstream side of the exhaust) is the same taper from the connection portion with the small diameter side of the taper portion 320 to the end that is open to the atmosphere. The diameter of the portion 320 is the same as that of the small diameter side.

In the 3rd muffler 300 in this embodiment, the following effects are obtained.
As described above, in the exhaust pipe having a hole in the wall surface, the vortex generated at the hole formation site is more easily separated from the hole formation site as the exhaust gas flow rate increases, A pressure wave that changes to a value is generated. When the fluctuation frequency of such a pressure wave coincides with the resonance frequency due to reflection of the wall surface constituting the exhaust system, a large resonance sound is generated from the exhaust system.

  Here, as shown in FIG. 3, it is known that there is a so-called boundary layer in the vicinity of the surface of the object through which the fluid flows, in which the fluid velocity is reduced due to the remarkable influence of the viscosity of the fluid. ing. Such a boundary layer is also present on the inner wall of the third exhaust pipe 30 through which the exhaust flows. In the boundary layer, the flow velocity of the exhaust gas becomes slower toward the inner wall. Also, the higher the exhaust flow rate, the thinner the boundary layer.

  In the present embodiment, the tapered portion 320 provided in the third silencer 300 increases the exhaust resistance by reducing the cross-sectional area of the exhaust flow path. The exhaust flow velocity in the vicinity of the end of the third exhaust pipe 30 connected to the exhaust upstream side of 320, that is, the large diameter side of the tapered portion 320 becomes slow. As described above, as shown in FIG. 4, the flow rate of the exhaust gas is reduced, so that the inner wall of the tapered portion 320 and the inner wall near the end of the third exhaust pipe 30 connected to the large diameter side of the tapered portion 320 are described above. The boundary layer develops. Therefore, even when the boundary layer in the third exhaust pipe 30 is likely to be thin due to an increase in the exhaust flow velocity, the end portion of the third exhaust pipe 30 connected to the inner wall of the tapered portion 320 or the larger diameter side of the tapered portion 320. On the inner wall in the vicinity, a boundary layer thicker than other portions is formed. The hole 330 is provided in the wall surface where the flow velocity of the exhaust gas is relatively slow due to the formation of such a thick boundary layer, that is, the wall surface of the end portion of the third exhaust pipe 30 connected to the large diameter side of the tapered portion 320. For this reason, the separation of the vortex generated at the formation site of the hole 330 is suppressed. As described above, in the third silencer 300 of this embodiment, the vortex flow generated at the site where the hole 330 is formed can be prevented from being peeled off. Is less likely to occur. Even if the engine operating state changes variously, it is difficult for resonance to occur, and the generation of resonance is suppressed in a wide range of engine operating states.

  Incidentally, in each of the above-mentioned Patent Documents 1 to 6, there are described those in which holes are provided in the wall surface of the taper portion and the wall surface of the exhaust pipe connected to the large diameter side of the taper portion. Then, for example, the exhaust gas flows into the exhaust pipe from the silencer chamber through a hole provided in the wall surface, and the silencer chamber and the hole constitute a part of the flow path through which the exhaust flows. For this reason, the exhaust flow when passing through the hole has a strong flow structure corresponding to the exhaust flow velocity. Therefore, in the silencer described in each of these patent documents, the flow of exhaust gas is less likely to stay in the boundary layer of the wall surface near the site where the hole is formed, and the development of the boundary layer in the vicinity of such site is unlikely to occur. It has become. On the other hand, in the present embodiment, the resonance chamber 340 communicates only with the inside of the third exhaust pipe 30, and further communicates with the inside of the third exhaust pipe 30 only through one hole 330. For this reason, the resonance chamber 340 and the hole 330 do not constitute a part of the flow path through which the exhaust flows, and the exhaust with strong flow is prevented from entering and exiting the hole 330. Due to such a difference in structure, in the third silencer 300 of the present embodiment, unlike the silencers described in Patent Documents 1 to 6, the flow of exhaust gas is made to flow in the boundary layer of the wall surface in the vicinity of the portion where the hole 330 is formed. The retention effect is enhanced, and the development of a boundary layer in the vicinity of such a site is promoted.

  On the other hand, the resonance generated by the conventional silencer as shown in FIG. 12 can be suppressed by further providing a silencer that reduces the resonance. However, in this case, since another silencer is required to provide one silencer, the arrangement space of the silencer becomes large. For this reason, such a plurality of silencers cannot be provided in a portion where the arrangement space of the silencer cannot be increased, such as the third exhaust pipe 30 provided at the end of the exhaust system. However, in the third silencer 300 of the present embodiment, since the generation of resonance can be suppressed as described above, it is not necessary to further provide a silencer that reduces the resonance, unlike the conventional silencer, It is also possible to install the silencer at a site where a large installation space cannot be taken.

  FIG. 5 shows an example of an experimental result of frequency analysis of the exhaust noise of the exhaust system provided with the third silencer 300. In FIG. 5, the exhaust noise of the exhaust system provided with the third silencer 300 is indicated by a solid line. Further, as a comparison object, the third silencer in which the tapered portion 320 is not formed and the hole 330 is provided in the linear third exhaust pipe, that is, the conventional structure having the conventional structure as shown in FIG. The exhaust noise of the exhaust system provided with three silencers is indicated by a two-dot chain line. Incidentally, the experimental results shown in FIG. 5 show the measurement results when the rotational speed of the internal combustion engine reaches 5000 r / min, in other words, the exhaust flow velocity is increased to some extent.

  As shown in FIG. 5, in the exhaust system provided with the third silencer 300, the sound pressure level from about 2 kHz to above 8 kHz is lower than that in the exhaust system provided with the conventional silencer. In particular, it was confirmed that the sound pressure level greatly decreased from around 2 kHz to 4 kHz.

As described above, according to the present embodiment, the following effects can be obtained.
(1) In the third silencer 300 in which the inside of the resonance chamber 340 and the inside of the third exhaust pipe 30 communicate with each other through a hole 330 provided in the wall surface of the third exhaust pipe 30, the third exhaust pipe 30 A tapered portion 320 is provided in the middle. Therefore, a thicker boundary layer is formed on the inner wall of the tapered portion 320 and the inner wall in the vicinity of the end of the third exhaust pipe 30 connected to the larger diameter side of the tapered portion 320. The hole 330 is provided in the wall surface where the flow velocity of the exhaust gas is relatively slow due to the formation of such a thick boundary layer, that is, the wall surface of the end portion of the third exhaust pipe 30 connected to the large diameter side of the tapered portion 320. Like that. As a result, the vortex flow generated at the site where the hole 330 is formed can be suppressed, and the fluctuation of the pressure wave, which is the cause of the resonance, is less likely to occur. Therefore, even if the engine operating state changes variously, it is difficult for resonance sound to be generated, and generation of resonance noise can be suitably suppressed in a wide range of engine operation states.

Further, it is possible to install the silencer at a site where the installation space of the silencer cannot be increased, such as the third exhaust pipe 30 provided at the end of the exhaust system.
(2) A tapered portion 320 having a reduced diameter toward the exhaust downstream side is formed. Therefore, the flow velocity of the exhaust in the vicinity of the end portion of the third exhaust pipe 30 connected to the tapered portion 320 or the exhaust upstream side of the tapered portion 320, that is, the large diameter side of the tapered portion 320 can be reduced. Accordingly, it is possible to favorably promote the development of the boundary layer at a portion where the flow velocity of the exhaust gas decreases (in the vicinity of the tapered portion 320 or the end portion of the third exhaust pipe 30 connected to the large diameter side of the tapered portion 320). .

In addition, the said embodiment can also be changed and implemented as follows.
If the third exhaust pipe 30 is provided with the tapered portion 320, as described above, not only the inner wall near the end of the third exhaust pipe 30 connected to the large diameter side of the tapered portion 320 but also the inner wall of the tapered portion 320. The boundary layer develops, and the flow velocity of the exhaust gas becomes slow even at the tapered portion 320. Therefore, as shown in FIG. 6, even if the hole 330 is provided in the wall surface of the tapered portion 320, the same effect can be obtained.

  -Although the taper part 320 of the said embodiment was diameter-reduced toward exhaust downstream, as shown in FIG. 7, you may make it provide the taper part 321 expanded in diameter toward exhaust downstream. . In this case, when the exhaust gas flows into the taper portion 321 from the third exhaust pipe 30 connected to the small diameter side of the taper portion 321 (the portion opened to the upstream side of the exhaust gas), the taper portion 321 causes the flow passage cross-sectional area of the exhaust gas to flow. Therefore, the flow of the exhaust gas is easily separated from the wall surface at the small diameter portion of the taper portion 321. Therefore, the flow velocity of the exhaust gas in the vicinity of the inner wall of the tapered portion 321 and the exhaust downstream side of the tapered portion 321, that is, the end portion of the third exhaust pipe 30 connected to the large diameter side of the tapered portion 321 becomes slow. For this reason, it is possible to favorably promote the development of the boundary layer at a portion where the flow velocity of the exhaust gas decreases (in the vicinity of the tapered portion 321 and the end portion of the third exhaust pipe 30 connected to the large diameter side of the tapered portion 321). . In this case as well, as shown in FIG. 7, a hole 330 is provided on the wall surface of the end of the third exhaust pipe 30 connected to the larger diameter side of the tapered portion 321, or the hole 330 is formed on the wall surface of the tapered portion 321. By providing, the effect according to the said embodiment is obtained. That is, the generation of resonance noise can be suitably suppressed in a wide range of engine operating conditions, and the silencer can be installed at a site where the installation space for the silencer cannot be increased.

  As shown in FIG. 8, by providing a reduced diameter portion 31 that returns to the original diameter after being reduced in diameter in a part of the third exhaust pipe 30, the tapered portion 320 is provided upstream of the reduced diameter portion 31 on the exhaust side. (The tapered portion reduced in diameter toward the exhaust downstream side) is formed, and the tapered portion 321 (the tapered portion enlarged in diameter toward the exhaust downstream side) is formed on the exhaust downstream side of the reduced diameter portion 31. It may be. In this case as well, by providing the hole 330 in the wall surface of the end portion of the third exhaust pipe 30 connected to the large diameter side of the tapered portion 320, it is possible to obtain the operational effect equivalent to the above-described embodiment and the above-described modification. . Moreover, in this modification, instead of providing the hole 330 in the wall surface at the end of the third exhaust pipe 30 connected to the larger diameter side of the taper portion 320, the wall surface of the taper portion 320, the wall surface of the taper portion 321 and the taper portion Even if the hole 330 is provided in any one of the wall surfaces of the end portion of the third exhaust pipe 30 connected to the large diameter side of 321, the same effect can be obtained.

  As shown in FIG. 9, the tapered portion 321 is provided on the exhaust upstream side of the enlarged diameter portion 32 by providing the enlarged diameter portion 32 that returns to the original diameter after being enlarged in a part of the third exhaust pipe 30. (Tapered portion enlarged toward the exhaust downstream side) and the tapered portion 320 (tapered portion reduced in diameter toward the exhaust downstream side) are formed on the exhaust downstream side of the enlarged diameter portion 32. It may be. Also in this case, by providing the hole 330 in the wall surface of the end portion of the third exhaust pipe 30 connected to the large diameter side of the tapered portion 321, it is possible to obtain the operational effects similar to those of the above-described embodiment and the above modification. . In this modification, instead of providing the hole 330 in the wall surface at the end of the third exhaust pipe 30 connected to the large diameter side of the tapered portion 321, the wall surface of the tapered portion 321 is connected to the large diameter side of the tapered portion 320. Even if the hole 330 is provided on any one of the wall surface of the end portion of the third exhaust pipe 30 and the wall surface of the tapered portion 320, the same effect can be obtained.

  In the third silencer 300 in the embodiment and the modification thereof, the inside of the resonance chamber 340 and the inside of the third exhaust pipe 30 are in direct communication via the hole 330. In addition, as shown in FIG. 10, the present invention is similarly applied to a case where a resonance tube 341 is provided in the resonance chamber 340 and one end of the resonance tube 341 is connected to the hole 330. be able to. Further, as shown in FIG. 11, a bottomed tubular tube 500 is provided on the outer peripheral surface of the third exhaust pipe 30, and one end of the tube 500 is connected to the hole 330, that is, a side branch. The present invention can be similarly applied to a silencer of the type that has one end connected to the hole 330.

  -In the said embodiment and its modification, one hole 330 was provided. In addition, the exhaust gas having a strong flow is prevented from entering and exiting the hole 330. In other words, the exhaust flow is likely to stay in the boundary layer of the wall surface in the vicinity of the portion where the hole 330 is formed. If the development of the boundary layer in the vicinity of such a part is promoted, a plurality of such holes 330 may be provided. When a plurality of holes 330 are provided as described above, for example, a configuration in which a plurality of holes 330 are provided in the circumferential direction of the third exhaust pipe 30 or the circumferential direction of the tapered portion 320 or the tapered portion 321, or the center of the third exhaust pipe 30 is provided. Examples include a configuration in which a plurality of holes 330 are provided in the axial direction or in the central axis direction of the tapered portion 320 or the tapered portion 321 and slightly shifted from each other.

Although the third silencer 300 is provided in the third exhaust pipe 30, a silencer having the same structure as the third silencer 300 is provided in the first exhaust pipe 10 and the second exhaust pipe 20. Also good.
-Although the muffler room formed in the 3rd muffler was a resonance room, other muffler rooms, for example, a sound absorption room provided with a sound absorption material etc., may be sufficient.

The schematic diagram which shows the exhaust system of the internal combustion engine in one Embodiment with which this is applied about the silencer for exhaust gas concerning this invention. Sectional drawing of the 3rd silencer in the embodiment. The conceptual diagram which shows the flow velocity distribution of the fluid which flows through the surface of an object. The A section enlarged view of FIG. The graph which shows the result of having performed the frequency analysis about the exhaust noise of an exhaust system provided with the 3rd silencer of the embodiment. Sectional drawing of the 3rd silencer in the modification of the embodiment. Sectional drawing of the 3rd silencer in the modification of the embodiment. Sectional drawing of the 3rd silencer in the modification of the embodiment. Sectional drawing of the 3rd silencer in the modification of the embodiment. Sectional drawing of the 3rd silencer in the modification of the embodiment. Sectional drawing of the 3rd silencer in the modification of the embodiment. Sectional drawing of the conventional silencer.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... 1st exhaust pipe, 11 ... Catalytic converter, 20 ... 2nd exhaust pipe, 30 ... 3rd exhaust pipe, 31 ... Diameter reduction part, 32 ... Diameter expansion part, 100 ... 1st silencer, 200 ... 2nd noise reduction 300 ... third silencer, 310 ... outer cylinder, 320 ... tapered portion, 321 ... tapered portion, 330 ... hole, 340 ... resonance chamber, 341 ... resonant tube, 500 ... tube.

Claims (6)

In the exhaust silencer in which the silencer chamber and the exhaust pipe communicate with each other through a hole provided in the wall surface of the exhaust pipe,
A taper portion is provided in the middle of the exhaust pipe, and the hole is provided in any one of the wall surface of the end portion of the exhaust pipe and the wall surface of the taper portion connected to the large diameter side of the taper portion. An exhaust silencer characterized by The exhaust silencer according to claim 1, wherein the tapered portion is reduced in diameter toward the exhaust downstream side. The exhaust silencer according to claim 1, wherein the taper portion has a diameter increased toward an exhaust downstream side. The exhaust silencer according to any one of claims 1 to 3, wherein the silencer chamber and the exhaust pipe are in direct communication with each other through the hole. The exhaust silencer according to any one of claims 1 to 3, wherein a resonance tube is provided in the silencer chamber, and the hole is connected to one end of the resonance tube. The exhaust pipe according to any one of claims 1 to 3, wherein the exhaust pipe is provided with a side branch type silencer, and the hole is connected to one end of the side branch type silencer. vessel.

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