JP2009062922A - Resonance device and exhaust device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resonance device and an exhaust device of an internal combustion engine capable of reducing unpleasant noise while preventing the increase in manufacturing cost. <P>SOLUTION: The exhaust device of an internal combustion engine is equipped with a main muffler connected to an engine, an exhaust pipe whose one end is connected to the main muffler, a sub muffler connected to the other end of the exhaust pipe, an exhaust pipe whose one end is connected to the sub muffler, and a resonance device connected to the other end of the exhaust pipe. The resonance device is constituted of an inner pipe 35 connecting the other end 34b of the exhaust pipe thereto and including a through hole 35a and an outer pipe 36 mounted to the inner pipe 35 so as to surround the periphery of the inner pipe 35 and demarcating a space becoming a resonance chamber 37 by a space with the outer periphery part of the inner pipe 35. The outer peripheral part of the other end 34b of the exhaust pipe is inserted into the inner pipe 35. Thus, the step difference 39 is formed at the connection part of the other end 34b of the exhaust pipe and the inner pipe 35. The through hole 35a is formed in the exhaust pipe 35 so as to be adjacent to the connection part of the other end 34b of the exhaust pipe 34 and the inner pipe 35. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a resonance device and an exhaust device for an internal combustion engine, and more particularly to a resonance device and an exhaust device for an internal combustion engine that are applied to a vehicle or the like and mute a specific frequency sound of exhaust gas discharged from the internal combustion engine.

In general, an internal combustion engine provided in a vehicle such as an automobile generates exhaust noise of various frequencies according to the number of rotations during operation of the internal combustion engine. . Therefore, in order to mute a sound with a specific frequency, it is important to be effective for the frequency and to have a great muffing effect.
In particular, when a specific frequency sound is generated depending on the structure of the silencer or the layout of the silencer and the exhaust pipe, a resonance device may be provided to mute the specific frequency sound.

  As a conventional resonance apparatus for muting a specific frequency sound of this type, there is one as shown in FIG. 9 (see, for example, Patent Document 1). In FIG. 9, the exhaust gas exhausted from the combustion chamber of the cylinder of the internal combustion engine is supplied to the resonance device 1 from the silencer (not shown) through the exhaust pipe, and this resonance device 1 is connected to the exhaust pipe. An inner pipe 2 that is attached to the inner pipe 2 so as to surround the inner pipe 2, and an outer pipe 3 that defines a space serving as a resonance chamber 4 between the outer periphery of the inner pipe 2. I have.

  A through hole 2a is formed in the inner pipe 2, and the exhaust gas supplied to the inner pipe 2 is directed to the resonance chamber 4 defined between the inner pipe 2 and the outer pipe 3 through the through hole 2a. By being radiated, the sound is silenced and exhausted through the inner pipe 2. Moreover, the frequency sound to be silenced can be adjusted by arbitrarily setting the volume of the resonance chamber 4. Specifically, the volume of the resonance chamber 4 is increased in order to mute the low frequency sound, and the volume of the resonance chamber 4 is decreased in order to mute the high frequency sound.

  By the way, in the resonance apparatus 1 having such a configuration, when high-speed exhaust gas is radiated from the inner pipe 2 to the resonance chamber 4 through the through-hole 2a when the internal combustion engine rotates at high speed, the whistling sound is generated. And unpleasant noise is generated.

  Specifically, when the flow rate of the exhaust gas introduced from the exhaust pipe to the inner pipe 2 becomes high at the time of high rotation of the internal combustion engine, a vortex is generated at the edge portion of the through hole 2a upstream of the exhaust gas in the exhaust direction. When this vortex flows downstream, it becomes a pressure wave with a fixed period, and this pressure wave becomes a vibration source and becomes a high-frequency air column resonance in the resonance chamber 4, so-called whistling sound is generated. End up.

  In order to prevent such whistling noises from being generated, there is one in which a silencer having a sound absorbing material is provided on the downstream side of the resonance device 1. In this way, a silencer having a sound absorbing material is provided. The manufacturing cost of the exhaust device will increase by the amount provided.

In order to prevent the whistling sound from being generated while suppressing the increase in the manufacturing cost of the exhaust device in this way, there is a silencer having a resonance device as shown in FIG. 10 (for example, Patent Document 2). reference).
In FIG. 10, the silencer body 11 of the silencer 10 is partitioned into a plurality of resonance chambers 15 and expansion chambers 16 a, 16 b, and 16 c by partition plates 12, 13, and 14. Are provided with an inlet pipe 18 having a through hole 18a, a communication pipe 19 having a plurality of through holes 19a, and an outlet pipe 20 as a resonance device having one through hole 20a.

  The outlet pipe 20 is formed to be bent in a U shape in order to mute low-frequency sound, and communicates with the resonance chamber 15 through the through hole 20a, and is upstream of the exhaust gas in the exhaust direction with respect to the through hole 20a. A convex portion 20b is formed on the inner wall on the side.

In the silencer configured as described above, when the flow rate of the exhaust gas becomes high at the time of high rotation of the internal combustion engine, the exhaust gas collides with the convex portion 20b provided on the upstream side of the through hole 20a. Thus, it is possible to prevent the generation of vortices, to prevent high-frequency column resonance, that is, the generation of whistling noise, and to reduce unpleasant noise.
JP 2006-29224 A Japanese Utility Model Publication No.3-33235

  However, in the silencer 10 having such a conventional outlet pipe 20, the convex portion 20b is formed on the inner wall of the outlet pipe 20 on the upstream side in the exhaust direction of the exhaust gas with respect to the through hole 20a. There is a problem that the convex portion 20b needs to be processed in the outlet pipe 20, and the manufacturing cost of the outlet pipe 20 increases accordingly, and as a result, the manufacturing cost of the silencer 10 increases.

  The present invention has been made to solve the above-described conventional problems, and provides a resonance device and an exhaust device for an internal combustion engine that can reduce unpleasant noise while preventing an increase in manufacturing cost. The purpose is to do.

  In order to achieve the above object, the resonance device according to the present invention is (1) provided in an exhaust device having a silencer for silencing exhaust gas discharged from an internal combustion engine, wherein the resonance device silences a specific frequency sound. Provided downstream of the silencer in the exhaust gas exhaust direction, one end of the exhaust pipe is connected to the silencer, and the other end of the exhaust pipe is connected, and has at least one through hole An exhaust pipe comprising: an inner pipe; and an outer pipe which is attached to the inner pipe so as to surround the inner pipe and defines a space serving as a resonance chamber between the outer periphery of the inner pipe. The other end of the exhaust pipe is inserted into the inner pipe to form a step at the other end of the exhaust pipe and the connecting portion of the inner pipe, and the through hole is connected to the other end of the exhaust pipe. And a one formed on the inner pipe so as to be close to the connecting portion of the inner pipe.

  With this configuration, when the exhaust gas introduced from the silencer through the exhaust pipe to the inner pipe passes through the step formed by the other end of the exhaust pipe and the connection portion of the inner pipe, the air current is disturbed. When exhaust gas collides with the edge of the through hole of the inner pipe located in the vicinity of the step, it is possible to prevent the vortex having a constant period from being generated. For this reason, a whistling sound can be prevented and unpleasant noise can be reduced.

  And since the flow of the exhaust gas can be disturbed by utilizing the step formed by the other end of the exhaust pipe and the connection part of the inner pipe, it is not necessary to process the exhaust pipe and the inner pipe. It is possible to prevent the manufacturing cost of the resonance device from increasing.

The resonance device according to (1) above is configured by (2) one in which one through hole is formed in the inner pipe.
With this configuration, when there is one through-hole formed in the inner pipe, exhaust gas collides with the edge of the through-hole and a vortex with a fixed period is generated, so that whistling noise is likely to occur. When the exhaust gas introduced into the gas passes through the step formed by the other end of the exhaust pipe and the connection part of the inner pipe, air currents can be disturbed, so that the edge of the through hole of the inner pipe When exhaust gas collides, it is possible to prevent the generation of a vortex with a constant period located in the vicinity of the step. For this reason, a whistling sound can be prevented and unpleasant noise can be reduced reliably.

In the resonance apparatus according to the above (1) or (2), (3) the through hole is formed at a position where an air current is disturbed when exhaust gas passes through the step.
With this configuration, the through-hole is formed at a position where the turbulence of the exhaust gas occurs when the exhaust gas passes through the step, so that the exhaust gas introduced into the inner pipe is prevented from being rectified before reaching the through-hole. Thus, when exhaust gas collides with the edge of the through hole, it is possible to reliably prevent the occurrence of a vortex with a constant period located near the step.

  In the exhaust device for an internal combustion engine provided with the resonance device according to any one of (1) to (3), (4) a first silencer connected to the internal combustion engine, and one end of the first silencer. A first exhaust pipe connected to the first exhaust pipe, a second silencer connected to the other end of the first exhaust pipe, and a second exhaust connected to one end of the second silencer An extension direction length of the first exhaust pipe and an extension direction length of the second exhaust pipe and the inner pipe are formed to be substantially the same length, and other than the second exhaust pipe The outer peripheral portion of the end portion is constituted by inserting the inner pipe of the resonance device.

The reason for this is as follows.
When the first silencer and the second silencer are spaced apart from each other in the vehicle front-rear direction, the exhaust pipe connecting the first silencer and the second silencer becomes longer, and the first silencer Low frequency sound due to air column resonance generated between the silencer and the second silencer is generated. When the first silencer and the second silencer are separated from each other, the second silencer is installed at the air column resonance node where the sound pressure is low. It becomes difficult to suppress.

  On the other hand, the first silencer and the second silencer are connected by the first exhaust pipe, and the length of the first exhaust pipe in the extending direction and the extension of the second exhaust pipe and the inner pipe of the resonance device are connected. If the present length is formed to be substantially the same length, the second silencer can be installed at the peak position of the sound pressure of the low frequency sound, and the low frequency sound can be efficiently silenced.

  However, if the extending direction length of the first exhaust pipe and the extending direction length of the second exhaust pipe and the inner pipe of the resonance device are formed to be substantially the same length, the first exhaust pipe and the second exhaust pipe are formed. And the resonance frequency of the inner pipe matches with that of the inner pipe, and a large high frequency sound is generated at a specific high frequency.

  Therefore, the present invention silences high-frequency sound by the resonance device by connecting a resonance device to the second exhaust pipe so that the upstream and downstream resonance frequencies of the second silencer do not coincide. . Then, exhaust gas introduced from the second silencer through the second exhaust pipe to the inner pipe when the internal combustion engine rotates at a high speed is formed by the other end of the second exhaust pipe and the connection portion of the inner pipe. As the air flow can be disturbed when passing through the step, when the exhaust gas collides with the edge of the through hole of the inner pipe, a vortex with a fixed period located near the step is generated. Can be prevented. For this reason, a whistling sound can be prevented and unpleasant noise can be reduced.

  And since the flow of the exhaust gas can be disturbed by using the step formed by the other end of the second exhaust pipe and the connection part of the inner pipe, it is unnecessary to process the exhaust pipe and the inner pipe. It is possible to prevent the manufacturing cost of the resonance device from increasing.

  In the exhaust system for an internal combustion engine according to the above (4), (5) the second silencer is connected to the other end of the first exhaust pipe and one end of the second exhaust pipe. An inner pipe having a through hole and an outer pipe attached to the inner pipe so as to surround the inner pipe and defining a space serving as a resonance chamber between the outer periphery of the inner pipe. And the resonance chamber is provided with a sound absorbing material.

  With this configuration, since the sound absorbing material is provided in the resonance chamber of the second silencer, the low frequency sound can be efficiently silenced by the sound absorbing material.

  ADVANTAGE OF THE INVENTION According to this invention, the resonance apparatus and the exhaust apparatus of an internal combustion engine which can reduce an unpleasant noise can be provided, preventing a manufacturing cost increasing.

DESCRIPTION OF EXEMPLARY EMBODIMENTS An embodiment of an exhaust device for an internal combustion engine including the resonance device and the resonance device according to the invention will be described below with reference to the drawings.
FIGS. 1-8 is a figure which shows one Embodiment of the exhaust apparatus of the internal combustion engine provided with the resonance apparatus which concerns on this invention, and a resonance apparatus. 1 is a top view of the exhaust device, and FIG. 2 is a front view of the exhaust device.

First, the configuration will be described.
1 and 2, an engine 21 as a four-cylinder internal combustion engine has a combustion chamber of each cylinder communicating with an exhaust manifold 22 via an exhaust port, and an exhaust device 23 is connected to the exhaust manifold 22. ing. The exhaust device 23 includes a catalytic converter 24, a main muffler 26 as a first silencer, a sub muffler 27 as a second silencer, and a resonator 28 as a resonance device. A catalytic converter separate from the catalytic converter 24 may be provided in the main muffler 26.

  The catalytic converter 24 is composed of a honeycomb base or a granular activated alumina support to which a catalyst such as platinum or palladium is attached and housed in a main body case. The reduction of NOx and the oxidation of CO and HC Is supposed to do.

  The main muffler 26 is connected to the catalytic converter 24 via the exhaust pipe 25, and performs primary noise reduction of the exhaust gas. One end 29 a of an exhaust pipe 29 as a first exhaust pipe is connected to the main muffler 26, and the other end 29 b of the exhaust pipe 29 is connected to the sub muffler 27.

  As shown in FIG. 3, the sub muffler 27 includes an inner pipe 30 in which the other end portion 29 b of the exhaust pipe 29 is fitted and a plurality of through holes 30 a are formed, and an inner pipe that surrounds the inner pipe 30. 30, an outer pipe 31 that defines a space serving as a resonance chamber 32 between the outer periphery of the inner pipe 30 and a sound absorbing material 33 filled in the resonance chamber 32.

  Further, one end 34 a of an exhaust pipe 34 as a second exhaust pipe is connected to the sub muffler 27, and one end 34 a of the exhaust pipe 34 is fitted to the inner pipe 30.

  The other end 34 b of the exhaust pipe 34 is connected to a resonator 28 provided downstream of the sub muffler 27 in the exhaust direction of the exhaust gas. As shown in FIGS. 4 and 5, the resonator 28 includes an inner pipe 35 having one through hole 35 a connected to the other end 34 b of the exhaust pipe 34, and an inner pipe 35 surrounding the inner pipe 35. An outer pipe 36 is provided which is attached to the pipe 35 and defines a space serving as a resonance chamber 37 between the outer periphery of the inner pipe 35.

  Further, the outer peripheral portion of the other end portion 34 b of the exhaust pipe 34 is inserted into the inner pipe 35, and a step 39 is formed at the connection portion between the other end portion 34 b of the exhaust pipe 34 and the inner pipe 35. Further, the through hole 35 a is formed in the inner pipe 35 so as to be close to a step 39 that is a connection portion between the other end 34 b of the exhaust pipe 34 and the inner pipe 35.

  Further, the length in the extending direction of the exhaust pipe 29 and the length in the extending direction of the inner pipe 35 of the exhaust pipe 34 and the resonator 28 are formed to be substantially the same length, and the through hole 35 a is discharged from the sub muffler 27. It is formed in the middle of the exhaust gas exhaust path.

  Further, the inner pipe 35 and the other end 34b of the exhaust pipe 34 are fastened by a flange member 38. The flange member 38 surrounds the other end 34b of the exhaust pipe 34 and the outer peripheral portion of the outer pipe 36. Is provided.

Next, a method for silencing exhaust gas will be described with reference to FIGS.
First, as shown in FIG. 6 (a), when the main muffler 26 and the sub muffler 27 are spaced apart from each other in the longitudinal direction of the vehicle as in the prior art, an exhaust pipe for connecting the main muffler 26 and the sub muffler 27 is provided. The sound pressure becomes maximum in a low frequency range where the frequency due to air column resonance generated between the main muffler 26 and the sub muffler 27 is about 40 Hz to 50 Hz. When the main muffler 26 and the sub muffler 27 are installed separately as described above, the sub muffler 27 is installed at the node of the air column resonance where the sound pressure is low, and it is difficult to suppress the low frequency sound. .

  On the other hand, in the present embodiment, as shown in FIG. 6B, the main muffler 26 and the sub muffler 27 are connected by the exhaust pipe 29, the length of the exhaust pipe 29 in the extending direction, the exhaust pipe 34, and the resonator. Since the extension direction length of the 28 inner pipes 35 is formed to be substantially the same length, the sub muffler 27 can be installed at the peak position of the sound pressure of the low frequency sound (position indicated by A in FIG. 6A). It is possible to mute low frequency sound efficiently. Further, since the sound absorbing material 33 is provided in the sub muffler 27, it is possible to mute the low frequency sound more efficiently.

  However, if the extending direction length of the exhaust pipe 29 and the extending direction length of the exhaust pipe 34 and the inner pipe 35 of the resonator 28 are formed to be substantially the same length, the exhaust pipe 29, the exhaust pipe 34, and the inner pipe 35 The resonance frequencies coincide with each other, and the high frequency sound becomes maximum at about 200 Hz.

  Therefore, in the present embodiment, the resonator 28 is connected to the exhaust pipe 34 so that the resonance frequencies on the upstream side and the downstream side of the sub muffler 27 do not coincide with each other, so that the high frequency sound is silenced by the resonator 28.

  Here, when the flow rate of the exhaust gas introduced from the exhaust pipe 34 to the inner pipe 35 becomes high at the time of high rotation of the engine 21, a vortex is generated at the edge portion of the through hole 35a upstream of the exhaust gas in the exhaust direction, When this vortex flows downstream, it becomes a pressure wave with a constant period, and this pressure wave becomes a vibration source, which causes high-frequency air column resonance in the resonance chamber 37, and so-called whistling noise is generated. There is.

  In the present embodiment, by inserting the outer peripheral portion of the other end 34b of the exhaust pipe 34 into the inner pipe 35, a step 39 is formed at the connection portion between the other end 34b of the exhaust pipe 34 and the inner pipe 35, and the exhaust pipe 34 is exhausted. Since the through-hole 35a is formed in the inner pipe 35 so as to be close to the step 39 which is the connecting portion between the other end 34b of the pipe 34 and the inner pipe 35, as shown in FIG. When the exhaust gas G introduced into the inner pipe 35 through the exhaust pipe 34 passes through the step 39, the turbulence of the airflow can be generated.

  For this reason, when exhaust gas collides with the edge part of the through-hole 35a of the inner pipe 35 located in the vicinity of the level | step difference 39, it can prevent that a vortex of a fixed period generate | occur | produces. For this reason, a whistling sound can be prevented and unpleasant noise can be reduced.

  Therefore, it is desirable that the through hole 35a is formed at a position where the turbulence of the airflow occurs when the exhaust gas passes through the step 39. If the through hole 35a is provided further downstream than this position, the exhaust gas There is a high possibility that rectification will occur and vortices with a certain period will be generated.

  FIG. 8 is a diagram showing the relationship between the rotational speed of the engine 21 and the sound pressure level generated in the exhaust device 23. In FIG. 8, the broken line indicates the sound pressure level of the present embodiment, and the solid line indicates the suppression of the whistling sound. This is the sound pressure level of the exhaust system not considered.

  As is apparent from FIG. 8, the sound pressure level in the frequency band at the peak of the sound pressure level could be reduced by nearly 10 dB at any high speed of the engine 21 at 5000 rpm or 5950 rpm. .

  As described above, in the present embodiment, the main muffler 26 connected to the engine 21, the exhaust pipe 29 having one end 29 a connected to the main muffler 26, and the sub muffler 27 connected to the other end 29 b of the exhaust pipe 29. And an exhaust pipe 34 having one end 34a connected to the sub-muffler 27, and a resonator 28 connected to the other end 34b of the exhaust pipe 34. The resonator 28 is connected to the other end 34b of the exhaust pipe 34. A space that is connected to the inner pipe 35 having the through-hole 35a and is attached to the inner pipe 35 so as to surround the inner pipe 35 and that serves as a resonance chamber 37 is defined between the outer periphery of the inner pipe 35 and the inner pipe 35. The outer pipe 36 and the other end 34b of the exhaust pipe 34 are inserted into the inner pipe 35 so that the other end 34b of the exhaust pipe 34 and the inner pipe 35 A step 39 is formed in the connection portion of the pipe 35, a through hole 35 a is formed in the inner pipe 35 so as to be close to the connection portion of the other end 34 b of the exhaust pipe 34 and the inner pipe 35, and the exhaust pipe 29 is further extended. The length in the extending direction and the length in the extending direction of the inner pipe 35 of the exhaust pipe 34 and the resonator 28 are formed to be substantially the same length.

  Therefore, the low-frequency sound can be efficiently silenced by the sub muffler 27, and the high-frequency sound can be efficiently silenced so that the upstream and downstream resonance frequencies of the sub-muffler 27 do not match.

  Further, the exhaust gas introduced from the sub muffler 27 through the exhaust pipe 34 into the inner pipe 35 of the resonator 28 when the engine 21 rotates at a high speed is formed by the connection portion between the other end 34 b of the exhaust pipe 34 and the inner pipe 35. Since the air flow can be disturbed when passing through the step 39, when the exhaust gas collides with the edge of the through hole 35a of the inner pipe 35 located in the vicinity of the step 39, a vortex having a fixed period is generated. It can be prevented from occurring. For this reason, a whistling sound can be prevented and unpleasant noise can be reduced.

  And since the air flow of exhaust gas can be disturbed using the level | step difference 39 formed by the connection part of the other end part 34b of the exhaust pipe 34 and the inner pipe 35, the exhaust pipe 34 and the inner pipe 35 are processed. Can be eliminated, and an increase in the manufacturing cost of the resonator 28 can be prevented.

  In particular, in the present embodiment, since the through hole 35a is formed at a position where the turbulence of the air flow occurs when the exhaust gas passes through the step 39, before the exhaust gas introduced into the inner pipe 35 reaches the through hole 35a. It is possible to prevent the vortex having a constant period from being generated when the exhaust gas collides with the edge of the through hole 35a.

  Further, the sub-muffler 27 of the present embodiment is connected to the other end 29b of the exhaust pipe 29 and the one end 34a of the exhaust pipe 34, and surrounds the inner pipe 30 having a plurality of through holes 30a and the inner pipe 30. In this way, the outer pipe 31 is attached to the inner pipe 30 and defines a space serving as a resonance chamber 32 between the outer periphery of the inner pipe 30 and the sound absorbing material 33 is provided in the resonance chamber 32. Since it comprised, the low frequency sound can be efficiently muffled by the sound-absorbing material 33.

  In the resonator 28 of the present embodiment, only one through hole 35a is provided in the inner pipe 35, but two or more through holes 35a may be provided. In particular, when there is only one through hole 35a formed in the inner pipe 35, there is only one place where vortices are generated. Therefore, exhaust gas collides with the edge of the through hole 35a and vortices with a fixed period are generated. Whistling sounds are likely to occur, but in the present embodiment, by using the step 39, it is possible to reliably prevent the occurrence of vortices with a fixed period by causing the turbulence of the air current as described above. .

  In the present embodiment, the length in the extending direction of the exhaust pipe 29 and the length in the extending direction of the inner pipe 35 of the exhaust pipe 34 and the resonator 28 are formed to be substantially the same length. Although the high frequency sound is muted as the sound, the resonator 28 according to the present embodiment has a specific frequency when a specific frequency sound is generated on the upstream side of the resonator 28 due to the muffler or exhaust pipe layout. The sound can be silenced, and the configuration of the muffler and exhaust pipe on the upstream side of the resonator 28 is not limited to this.

  In addition, the embodiment disclosed this time is illustrative in all respects and is not limited to this embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

  As described above, the resonance device and the exhaust device of the internal combustion engine according to the present invention have an effect of reducing unpleasant noise while preventing an increase in manufacturing cost, and are discharged from the internal combustion engine. It is useful as a resonance device that silences a specific frequency sound of exhaust gas, an exhaust device of an internal combustion engine, and the like.

It is a figure which shows one Embodiment of the resonance apparatus which concerns on this invention, and the exhaust apparatus of an internal combustion engine, and is a top view of an exhaust apparatus. It is a figure which shows one Embodiment of the resonance apparatus which concerns on this invention, and the exhaust apparatus of an internal combustion engine, and is a front view of an exhaust apparatus. It is a figure which shows one Embodiment of the resonance apparatus which concerns on this invention, and the exhaust apparatus of an internal combustion engine, and is sectional drawing of a sub muffler. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows one Embodiment of the resonance apparatus which concerns on this invention, and the exhaust apparatus of an internal combustion engine, and is an external view of a resonance apparatus. It is a BB direction arrow sectional view of Drawing 4. It is a figure which shows one Embodiment of the resonance apparatus which concerns on this invention, and the exhaust apparatus of an internal combustion engine, (a) is a figure which shows the sound pressure mode by air column resonance at the time of installing apart a sub muffler and a main muffler, b) is a diagram showing a sound pressure mode by air column resonance of the exhaust device of the present invention. It is a figure which shows one Embodiment of the resonance apparatus which concerns on this invention, and the exhaust apparatus of an internal combustion engine, and is a figure which shows the flow of the exhaust gas which flows in into the level | step-difference part of a resonance apparatus. It is a figure which shows one Embodiment of the resonance apparatus which concerns on this invention, and the exhaust apparatus of an internal combustion engine, and is a figure which shows the relationship between the engine speed and the sound pressure level which generate | occur | produces in an exhaust apparatus. (A) is sectional drawing of the conventional resonance apparatus, (b) is CC sectional view taken on the line of the CC direction of the figure (a). (A) is sectional drawing of the silencer provided with the conventional resonance apparatus, (b) is a DD direction arrow sectional drawing of the figure (a).

Explanation of symbols

21 Engine (Internal combustion engine)
23 Exhaust device 26 Main muffler (first silencer)
27 Sub-muffler (second silencer)
28 Resonator (resonance device)
29 exhaust pipe 29a one end 29b other end 30 inner pipe 30a through hole 31 outer pipe 32 resonance chamber 33 sound absorbing material 34 exhaust pipe 34a one end 34b other end 35 inner pipe 35a through hole 36 outer pipe 37 resonance chamber 39 step

Claims (5)

In a resonance apparatus that is provided in an exhaust device having a silencer that silences exhaust gas discharged from an internal combustion engine and silences a specific frequency sound,
An exhaust pipe provided on the downstream side in the exhaust direction of the exhaust gas with respect to the silencer, one end of which is connected to the silencer;
The other end of the exhaust pipe is connected to the inner pipe having at least one through hole, and the inner pipe is attached to the inner pipe so as to surround the inner pipe, and between the outer pipe and the outer peripheral portion of the inner pipe. And an outer pipe in which a space to be a resonance chamber is defined,
By inserting the outer peripheral portion of the other end portion of the exhaust pipe into the inner pipe, a step is formed in the connection portion between the other end portion of the exhaust pipe and the inner pipe, and the through hole is connected to the other end of the exhaust pipe. A resonance device, wherein the resonance device is formed in the inner pipe so as to be close to a connection portion between an end portion and the inner pipe. The resonance device according to claim 1, wherein one through hole is formed in the inner pipe. 3. The resonance device according to claim 1, wherein the through hole is formed at a position where turbulence of an air flow occurs when exhaust gas passes through the step. 4. An exhaust system for an internal combustion engine comprising the resonance device according to any one of claims 1 to 3,
A first silencer connected to the internal combustion engine, a first exhaust pipe having one end connected to the first silencer, and a second exhaust connected to the other end of the first exhaust pipe. A silencer, and a second exhaust pipe having one end connected to the second silencer,
The length in the extending direction of the first exhaust pipe and the length in the extending direction of the second exhaust pipe and the inner pipe are formed to be substantially the same length, and the outer peripheral portion of the other end of the second exhaust pipe Is inserted through the inner pipe of the resonance device. The second silencer is connected to the other end of the first exhaust pipe and one end of the second exhaust pipe, and surrounds the inner pipe having a plurality of through holes and the inner pipe. An outer pipe that is attached to the inner pipe and that defines a space serving as a resonance chamber between the outer periphery of the inner pipe and a sound absorbing material is provided in the resonance chamber. Item 5. An exhaust system for an internal combustion engine according to Item 4.

Images