JPH07189650A - Muffler for internal combustion engine - Google Patents

Abstract

PURPOSE:To realize silencing of a belt range extending from a low range to intermediate and high ranges with exhaust pressure low loss by providing an inner pipe part in the inside of a porous pipe, and providing an opening port part in the inner pipe part so as to lead exhaust fluid into a clearance space formed between the porous pipe and the inner pipe part, while providing the inner pipe part in the porous pipe. CONSTITUTION:Exhaust gas from an engine is led to a leading pipe 24, a porous pipe 25 having multiple small holes is connected to the leading pipe 24 linearly. An inner pipe part 27 which is made of a pipe having a prescribed length is provided fixedly in the inner part of the porous pipe 25, and it is formed as a double pipe structure. A clearance space is formed between the porous pipe 25 and the inner pipe part 27, the pipe end part 27a of the leading inlet side of the inner pipe part 27 is formed as an opening part or an opening end, and exhaust fluid which is led into the porous pipe 25 flows into the clearance space. Exhaust fluid is forcibly led from the opening part into the clearance space, and the exhaust fluid which flows into the clearance space is compressed, so that expansion, influence, and the like of vibration wave of the exhaust fluid are promoted passing the small holes of the porous pipe 25. It is thus possible to more promote silencing effect.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a muffler for an automobile engine and other internal combustion engines, and more particularly to a muffler of exhaust pressure low loss type.

[0002]

2. Description of the Related Art As an example of a conventional muffler for an automobile, those shown in FIGS. 6 and 7 are known. The muffler 1 shown in FIG. 6 has four partitioned chambers 2, 3, 4, 5 and has an engine (not shown).
Exhaust gas discharged from the chamber flows into the chamber 4 through the introduction pipe 6, and passes from the chamber 4 through the communication pipe 7 having many small holes to the chamber 2
It is adapted to flow in, further flow from the chamber 2 into the outlet pipe 8 and be discharged. Further, the chamber 4 is connected to the chamber 5 through the pipe 9.
Is in communication with. With this configuration, sound wave expansion, resonance,
The effects of interference, resistance, etc. occur, and the exhaust noise can be silenced in a predetermined frequency band.

The muffler 10 shown in FIG.
1 is provided with a perforated pipe 13 in which the lead-out pipe 12 communicates in a straight line, the perimeter of the perforated pipe 13 is covered with a filter 14, and a sound absorbing material 15 such as glass wool is filled in the surrounding room. Become. In this case, sound absorption in the predetermined frequency band is performed by the sound absorption characteristics of the sound absorbing material 15.

[0004]

In the muffler 1 shown in FIG. 6, the sound pressure level is reduced by making the exhaust path complicated and long. Therefore, the sound deadening characteristics are good, but on the other hand, the loss and resistance of the exhaust pressure are increased, and a significant adverse effect occurs at high rotation and high load.
On the other hand, the muffler 10 shown in FIG. 7 is a low exhaust pressure loss type because it can be exhausted in a straight line, but it can only muffle the specific frequency band of the sound absorbing material.
In particular, it was not possible to muffle the low frequency band. In particular, it was not possible to muffle sound in the band of 70 Hz to 90 Hz, which is the vibration frequency of the vehicle interior cavity resonance. The present invention has been made in view of the above points, and it is an object of the present invention to provide a muffler for an internal combustion engine, which has a good muffling characteristic. Further, another object of the present invention is to provide a muffler for an internal combustion engine, which is of a low exhaust pressure loss type and has a good muffling characteristic.

[0005]

A muffler for an internal combustion engine according to the present invention is provided with an inlet for introducing exhaust fluid, a chamber provided inside, and a guide for introducing the exhaust fluid to the outside. A muffler body having an outlet and a perforated tube having a plurality of small holes on its side surface, which is housed inside the muffler body and has a space inside the tube leading to the inlet and the outlet. And a porous pipe portion communicating with the chamber through the plurality of small holes, for guiding the exhaust fluid introduced from the inlet to the outlet and diffusing into the chamber through the plurality of small holes. And an inner pipe portion inserted inside the perforated pipe and an exhaust fluid introduced into the perforated pipe portion from the introduction port to a gap space formed between the perforated pipe and the inner pipe portion. And an opening provided in the inner tube It is.

In the muffler according to the present invention, the opening is formed by making an end portion of the inner pipe portion on an upstream side of exhaust gas an open end. In the muffler according to the present invention, the inner pipe portion is close to the perforated pipe portion at a predetermined portion of the inner pipe portion on the downstream side of exhaust gas so that the gap is minimized. It is what The muffler according to the present invention is characterized in that the inner pipe portion is in close contact with the perforated pipe portion at a predetermined position of the inner pipe portion on the downstream side of exhaust gas. The muffler according to the present invention is characterized in that the gap is closed at a predetermined position on the downstream side of the exhaust gas. In the muffler according to the present invention, the relative relationship between the outer diameter of the inner pipe portion and the inner diameter of the perforated pipe portion is changed so that the gap becomes gradually narrower from the upstream side toward the downstream side of the exhaust gas. It is characterized in that it is set to. In the muffler according to the present invention, the relative relationship between the outer diameter of the inner pipe portion and the inner diameter of the perforated pipe portion such that the gap gradually narrows from the upstream side toward the downstream side of the exhaust gas. Is set to change. In the muffler according to the present invention, the gap is substantially constant in a predetermined range from the upstream side of the exhaust gas, and the outer diameter of the inner pipe portion and the inner diameter of the perforated pipe portion are narrowed so as to be throttled at the end portion. It is characterized in that a relative relationship is set.

According to another aspect, a muffler for an internal combustion engine according to the present invention is provided between an inlet and an outlet of an exhaust fluid, and a porous pipe having a plurality of small holes on its side surface,
A side wall of the perforated tube is hermetically sealed to form a space communicating with the small hole, and a tube having a predetermined length provided inside the perforated tube to form a gap space with the perforated tube. And an inner tube portion that is closer to the inlet port, and the gap space closer to the outlet port is narrower than the gap space closer to the inlet port.

According to another aspect, a muffler for an internal combustion engine according to the present invention is provided between an inlet and an outlet for exhaust fluid, and has a porous tube having a plurality of small holes on its side surface.
A side wall of the perforated tube is hermetically sealed to form a space communicating with the small hole, and a tube having a predetermined length provided inside the perforated tube to form a gap space with the perforated tube. And an inner tube portion that is close to the inlet, and the gap space near the inlet is opened in the perforated pipe, and the gap space near the outlet is closed.

According to another aspect, a muffler for an internal combustion engine according to the present invention is provided between an inlet and an outlet for exhaust fluid, and has a porous tube having a plurality of small holes on its side surface.
A chamber formed by hermetically sealing the side surface of the perforated pipe and forming a space communicating with the small hole, and a pipe of a predetermined length provided inside the perforated pipe, and having a diameter of a pipe end portion near the introduction port. Also has an inner pipe portion in which the diameter of the pipe end portion near the outlet is larger.

According to another aspect, a muffler for an internal combustion engine according to the present invention is provided between an inlet and an outlet of an exhaust fluid, and a porous pipe having a plurality of small holes on its side surface,
The porous tube and the inner tube are formed by sealing a side surface of the porous tube and forming a space communicating with the small hole, and an inner tube having a predetermined length inserted into the porous tube. And an outer diameter of the inner pipe relative to an inner diameter of the perforated pipe is changed so that the gap is formed closer to the outlet than to the inlet. It is provided with a pipe portion and a second chamber communicating with the first chamber via a communication pipe.

According to another aspect, a muffler for an internal combustion engine according to the present invention is provided between an exhaust fluid inlet and an exhaust fluid outlet, and has a first multi-hole having a plurality of small holes on its side surface. A porous tube, a first chamber that seals a side surface of the perforated tube and forms a space that communicates with the small hole, and an inner tube of a predetermined length that is inserted into the perforated tube. A gap is formed between the inner pipe and the outer diameter of the inner pipe relative to the inner diameter of the perforated pipe so that the gap is closer to the outlet than to the inlet. Inner tube part
The first portion is provided between the inlet and outlet of the exhaust fluid.
A second perforated tube which is provided before or after the perforated tube and has a plurality of small holes on its side surface, and a side surface of the second perforated tube is hermetically sealed. And a second chamber in which a sound absorbing material is housed in the space.

According to another aspect, a muffler for an internal combustion engine according to the present invention has an inlet for introducing exhaust fluid, an internal space, and an outlet for exhausting the exhaust fluid to the outside. A muffler main body having a perforated tube having a large number of small holes on the side surface, and the space inside the tube is accommodated inside the muffler main body and communicates with the inlet and the outlet, A perforated pipe portion that guides the exhaust fluid introduced from the inlet to the outlet and diffuses into the space inside the muffler body through the large number of small holes,
The porous tube includes an inner tube of a predetermined length inserted inside the perforated tube, and a gap is formed between the inner tube and the perforated tube so that the gap is minimized at a location near the downstream of exhaust gas. An inner tube portion including a portion in close contact with the tube portion.

According to another aspect, the inner pipe portion may include a portion relatively close to the perforated pipe portion so as to minimize the gap at a position on the downstream side of the exhaust gas. . According to another aspect, the inner pipe portion is open at an end portion of the inner pipe upstream of the exhaust gas, allows the exhaust fluid to enter the gap from the open end, and is located at a downstream portion of the exhaust gas. In the above, it may include a portion in close contact with the perforated pipe portion so that the gap is minimized. According to another aspect, the inner pipe portion is open at an end portion of the inner pipe upstream of the exhaust gas, allows the exhaust fluid to enter the gap from the open end, and is located at a downstream portion of the exhaust gas. In the above, it may include a portion relatively close to the perforated pipe portion so that the gap is minimized.

[0014]

The muffler for an internal combustion engine according to the present invention is characterized in that it has a double pipe structure in which an inner pipe portion is provided inside a perforated pipe. First, due to the structure in which a large number of small holes of the perforated pipe communicate with the internal space of the muffler body that houses the perforated pipe, the exhaust fluid passing through the perforated pipe diffuses into the internal space through the small holes, and exhaust fluid vibration Functions such as wave diffusion and interference occur. This contributes to silencing in a predetermined frequency band (for example, a middle and high frequency band). Here, it is a structure having a double pipe structure in which the inner pipe portion is inserted into the inside of the perforated pipe, and the exhaust fluid introduced into the perforated pipe portion from the inlet is supplied to the perforated pipe and the inner pipe portion. By providing the opening provided in the inner pipe portion so as to be guided to the clearance space formed between the exhaust gas, the exhaust fluid is vigorously guided from the opening to the clearance space, and the exhaust gas entering the clearance space is exhausted. The fluid is compressed and the vibration waves of the exhaust fluid diffuse through the small holes of the perforated pipe,
Interference will be promoted. Therefore, it has an excellent effect that the sound deadening effect can be further promoted.

In addition, the inner tube portion is inserted into the inside of the perforated tube to form a double tube structure, and the gap space formed between the inner wall of the perforated tube and the outer wall of the inner tube portion has an inlet portion (introduction). By having a relatively wide area near the mouth or upstream of the exhaust) and a relatively narrow, narrowed or closed state at the outlet (close to the outlet or downstream of the exhaust) As a result, the outlet portion of the clearance space is generally throttled, and the compression of the exhaust fluid that has entered the clearance space is further promoted. As a result, the vibration wave of the exhaust fluid through the small holes of the perforated pipe is increased. It is possible to further promote the diffusion, interference, etc., and to further enhance the sound deadening effect, which is an excellent effect.

That is, considering the cross-sectional area of the clearance space formed between the perforated pipe and the inner pipe portion inside thereof, the pipe end portion of the inner pipe portion near the inlet and the inner wall of the perforated pipe are considered. The cross-sectional area of the space between them (tentatively referred to as the gap space inlet) is greater than the cross-sectional area of the space between the pipe end near the outlet of the inner pipe and the inner wall of the porous pipe (tentatively referred to as the gap space outlet). Is also wide. That is, since the gap space inlet is wider than the gap space outlet, the exhaust fluid entering the gap space of the double pipe structure of the perforated pipe and the inner pipe portion is compressed due to the narrowed outlet. Therefore, the diffusion and interference of the vibration waves of the exhaust fluid through the small holes of the perforated pipe are promoted, and therefore, the silencing effect can be further promoted, which is an excellent effect. is there.

The pipe end portion of the inner pipe portion near the outlet may be in close contact with the inner wall of the perforated pipe so as to completely close the gap space outlet, or appropriately. The space may be opened so that the outlet of the clearance space is not completely closed. In short, any structure may be used as long as it narrows the outlet of the gap space of the double pipe structure.
Further, the cross-sectional shape of the tube is not necessarily circular, but may be any shape such as an ellipse or a polygon. Therefore, the size of the diameter of the pipe in the present invention is synonymous with the size of its cross-sectional area.

The muffler according to the present invention is only required to have the double tube structure as described above at least in part, and any structure may be added thereto. Illustrative embodiments of some additional structures are as follows. Apart from the chamber leading to the small hole of the perforated pipe (this is referred to as the first chamber for convenience),
Further, a second chamber may be provided, and the second chamber may communicate with the first chamber via a communication pipe. 1st by connecting pipe
The Helmholtz resonator is constituted by the structure leading from the chamber to the second chamber, and contributes to silencing in a predetermined low frequency band. The communication pipe is not limited to one, but a plurality of communication pipes may be provided, and a Helmholtz resonator is configured corresponding to each of the communication pipes and contributes to silencing in a predetermined low frequency band. By properly setting this resonator, a predetermined low frequency band (for example, 200
Hz to 300 Hz) can be set to achieve silence. Therefore, in combination with the silencing effect in the mid-high range through the small holes of the perforated tube, it has an excellent advantage that the silencing in a wide range from the low range to the mid-high range can be achieved by a simple two-chamber structure. Become.

A sound absorbing material may be provided in the space of the chamber communicating with the small hole of the perforated pipe. As a result, the sound absorption characteristic of the sound absorbing material makes it possible to clean the sound in the predetermined frequency band, and the sound deadening effect can be further enhanced. In addition, a second chamber provided separately from the chamber communicating with the small hole of the perforated pipe (this chamber is referred to as a first chamber for convenience), and the chamber between the inlet and outlet of the exhaust fluid. A second perforated tube having a plurality of small holes on the side surface provided before or after the first perforated tube and an outer circumference of the second perforated tube are hermetically sealed, and the small holes of the second perforated tube are formed. There may be an indoor space communicating with the second space, and a second chamber having a sound absorbing material housed in the space. Also in this case, the sound absorption characteristic of the sound absorbing material can be used to muffle the sound in a predetermined band. Further, the above embodiments may be combined in various ways.

Further, by making the exhaust passage communicate with the exhaust passage from the inlet of the exhaust to the outlet of the exhaust in a straight line, the resistance and loss exerted on the exhaust pressure can be remarkably suppressed. It can be used as a muffler and can greatly contribute to fuel efficiency and improvement of power performance.

[0021]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In FIG. 1, the muffler body 20
Is the two chambers separated by the partition wall 23, namely the first chamber
It has a two-chamber structure having a chamber 21 and a second chamber 22. Exhaust gas from the engine (not shown) is introduced into the intake pipe
A perforated pipe 25 having a large number of small holes introduced therein (corresponding to the introduction port) is linearly connected to the introduction pipe 24. A lead-out pipe 26 (corresponding to a lead-out port) for leading out the exhaust gas is linearly connected to the perforated pipe 25. Therefore,
Since the exhaust gas linearly passes through the muffler body 20, it has an extremely efficient exhaust pressure low loss structure. The perforated tube 25 is provided corresponding to the first chamber 21, and communicates with the first chamber 21 through a large number of small holes provided on the side surface of the perforated tube 25. As a result, diffusion (expansion), interference, and the like of the exhaust sound vibration wave occur, and it is possible to muffle a predetermined middle and high range (for example, air flow sound) by the porous resonance type muffling effect.

Inside the perforated pipe 25, an inner pipe portion 27 made of a pipe having a predetermined length is fixedly provided, and has a double pipe structure. The inner pipe portion 27 is characterized in that its pipe diameter is larger at the pipe end portion 27b near the outlet port than at the exhaust fluid inlet port 27a. The specific structure of the inner pipe portion 27 may be variously designed. For example, as shown in the drawing, the pipe end portion 27b near the outlet port
May have a large diameter and other diameters smaller than that may have substantially the same diameter. Alternatively, the present invention is not limited to this, and may have a tapered pipe structure in which the diameter gradually increases from the pipe end portion 27a near the inlet port to the pipe end portion 27b near the outlet port. Alternatively, the structure may be such that the diameter gradually increases in several steps from the pipe end portion 27a near the inlet port to the pipe end portion 27b near the outlet port. Further, the pipe end portion 27b near the outlet may be in close contact with the inner wall of the perforated pipe 26 over the entire circumference thereof, or an appropriate space may be left open. In short, any structure may be used as long as it narrows the outlet of the gap space of the double pipe structure.

Due to the double tube structure as described above, the perforated tube 2
The cross-sectional area of the gap space formed between the inner pipe portion 27 and the inner pipe portion 27 corresponds to the space between the pipe end portion 27a near the inlet of the inner pipe portion and the inner wall of the perforated pipe 25 (provisionally referred to as a gap space inlet). The cross-sectional area is larger than the cross-sectional area of the space (provisionally referred to as a clearance space outlet) between the pipe end portion 27b near the outlet of the inner pipe portion and the inner wall of the porous pipe 25. That is, since the gap space inlet is wider than the gap space outlet, the exhaust fluid entering the gap space of the double pipe structure of the perforated pipe 25 and the inner pipe portion 27 is compressed by the outlet being compressed. As a result, the diffusion and interference of the vibration wave of the exhaust fluid through the small holes of the perforated pipe 25 are promoted. Therefore, it is possible to further promote the sound deadening effect in a predetermined middle and high band. As shown in the drawing, the pipe end portion 27a of the inner pipe portion 27 near the inlet is an opening or an open end so that the exhaust fluid introduced into the perforated pipe 25 can flow into the gap space. It has become.

In the embodiment of FIG. 1, from the first chamber 21 to the second chamber
A communication pipe 28 communicating with the chamber 22 is provided. This constitutes a Helmholtz resonator (first resonator), and contributes to silencing in a predetermined low frequency band. Further, a second communication pipe 29 that communicates with the first chamber 21 and the second chamber 22 is provided at another position. This also
It constitutes a Helmholtz resonator (second resonator) and contributes to silencing in a predetermined low frequency band. In this way, these two types of resonators can contribute to the silencing of two types of different low frequency bands.

The pipe length and / or the pipe diameter of the inner pipe portion 27 are appropriately set, the pipe length of the perforated pipe 25, the size and the number of small holes, etc. are also set appropriately, and the communicating pipe 28 constituting the resonator is formed. , 29, by appropriately setting the number of tubes, the tube length, and the tube diameter, etc., while suppressing the noise in the band of 70 Hz to 90 Hz which is the so-called muffled sound of the resonance frequency in the vehicle interior cavity, Of the low frequency band (for example, 200 Hz to 300 Hz) can be achieved, and in combination with the silencing of the mid-high range through the small holes of the perforated pipe, silencing of a wide range from the low range to the mid-high range can be easily performed. It can be achieved by a chamber structure.

FIG. 2 is a diagram showing another embodiment of the present invention. In this embodiment, as in the muffler body 10 shown in FIG. 7, the muffler body 10A has an exhaust fluid inlet pipe 11 (corresponding to an inlet port) and an outlet pipe 12 (corresponding to an outlet port) in a straight line. The porous pipe 13 is provided in communication with the perforated pipe 13. The perimeter of the porous pipe 13 is covered with a filter 14, and a sound absorbing material 15 such as glass wool is filled in the room around the filter. Inside the perforated pipe 13, an inner pipe portion 27 having the same configuration as that of FIG. 1 is provided. In this case, in addition to the sound deadening effect of the porous tube 13 promoted by the inner tube portion 27, sound deadening in a predetermined frequency band is performed by the sound absorbing characteristics of the sound absorbing material 15.

FIG. 3 is a diagram showing still another embodiment of the present invention. In this embodiment, the muffler body 20A
Has a two-chamber structure consisting of a first chamber 21 and a second chamber 22, similar to the muffler body 20 shown in FIG.
Inside the perforated pipe 25 corresponding to the first chamber 21, an inner pipe portion 27 having the same configuration as in FIG. 1 is provided. The pipe 30 corresponding to the second chamber 22 is a perforated pipe having a large number of small holes. Further, as in the case of FIG. 2, the inside of the second chamber 22 has a configuration in which the circumference of the tube 30 made of a perforated tube is covered with a filter 31, and the surrounding room is filled with a sound absorbing material 32 such as glass wool. Has become. In this case, the first chamber 2
No communication pipe is provided between the first and second chambers 22.
Also in this case, the perforated pipe 25 promoted by the inner pipe portion 27
In addition to the sound deadening effect in the first chamber 21 due to, the sound deadening effect in the second chamber 22 due to the sound absorbing characteristics of the sound absorbing material 32 can be obtained. In this case, the first chamber 21 and the second chamber 22 may be separated. In addition, the second equipped with the sound absorbing material 32
The chamber 22 may be arranged in front of the first chamber 21.

FIG. 4 is a diagram showing still another embodiment of the present invention. In this embodiment, the first muffler body 2
0 has the same configuration as the muffler body 20 shown in FIG. 1. The second muffler body 10 is provided before the first muffler body 20. The second muffler body 10 has the same structure as the muffler body 10 of FIG. 7.
Therefore, also in this case, in addition to the sound deadening effect in the first muffler body 20 by the perforated tube 25 promoted by the inner tube portion 27, the sound deadening effect in the second muffler body 10 by the sound absorbing characteristic of the sound absorbing material 15 is obtained. Therefore, it is possible to cleanly remove noise in a band that cannot be completely removed by the embodiment of FIG. FIG. 5 shows an example of the muffling characteristic according to the embodiment of FIG. 4, a solid line shows an example of the muffling characteristic by the first muffler body 20, and a broken line shows an example of the muffling characteristic by the second muffler body 10. .

[0029]

As described above, according to the present invention, a large number of small holes of the perforated pipe communicate with the space inside the muffler body accommodating the perforated pipe. It diffuses into the internal space through the small holes and causes the effects of diffusion and interference of the exhaust fluid vibration wave, which contributes to the silencing of a predetermined frequency band. The structure has a double-pipe structure in which the pipe portion is inserted, and the exhaust fluid introduced into the perforated pipe portion from the inlet is guided to the gap space formed between the perforated pipe and the inner pipe portion. By providing the opening provided in the inner pipe portion, the exhaust fluid is vigorously guided from the opening to the gap space, the exhaust fluid entering the gap space is compressed, and the small hole of the perforated pipe is formed. Diffusion of the vibration wave of the exhaust fluid through
Interference will be promoted. Therefore, it has an excellent effect that the sound deadening effect can be further promoted.

In addition, the inner pipe portion is inserted into the inside of the perforated pipe to form a double pipe structure, and the gap space formed between the inner wall of the perforated pipe and the outer wall of the inner pipe portion has an inlet portion (introduction). By having a relatively wide area near the mouth or upstream of the exhaust) and a relatively narrow, narrowed or closed state at the outlet (close to the outlet or downstream of the exhaust) As a result, the outlet portion of the clearance space is generally throttled, and the compression of the exhaust fluid that has entered the clearance space is further promoted. As a result, the vibration wave of the exhaust fluid through the small holes of the perforated pipe is increased. It is possible to further promote the diffusion, interference, etc., and to further enhance the sound deadening effect, which is an excellent effect.

Further, by adopting the straight exhaust structure, the resistance and loss exerted on the exhaust pressure can be remarkably suppressed, and the fuel consumption and the power performance can be greatly improved.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a muffler according to the present invention.

FIG. 2 is a schematic sectional view showing another embodiment of the muffler according to the present invention.

FIG. 3 is a schematic sectional view showing still another embodiment of the muffler according to the present invention.

FIG. 4 is a schematic sectional view showing still another embodiment of the muffler according to the present invention.

FIG. 5 is a diagram showing an example of a silencing characteristic of the same embodiment.

FIG. 6 is a schematic sectional view showing an example of a conventional muffler.

FIG. 7 is a schematic cross-sectional view showing another example of a conventional muffler.

[Explanation of symbols]

 1, 10, 20, 10A, 20A Muffler body 21 First chamber 22 Second chamber 23 Partition wall 24 Introducing pipe (introducing port) 25 Perforated pipe 26 Outlet pipe (outleting port) 27 Inner pipe part 27a Introducing inner pipe part Pipe end part 27b near the mouth 27b Pipe end part near the outlet of the inner pipe part 28,29 Communication pipe 15,32 Sound absorbing material

Claims (19)

[Claims] 1. A muffler body having an inlet for introducing exhaust fluid, a chamber provided inside, and an outlet for leading out the exhaust fluid to the outside, and a plurality of small holes on a side surface. It includes a perforated tube having, is housed inside the muffler body, and the space inside the tube communicates with the inlet and the outlet, and communicates with the chamber through the plurality of small holes. A porous pipe part that guides the exhaust fluid introduced from the introduction port to the outlet port and diffuses it into the chamber through the plurality of small holes; and an inner pipe part inserted inside the porous pipe. The exhaust fluid introduced into the perforated pipe portion from the introduction port,
A muffler for an internal combustion engine, comprising: an opening provided in the inner pipe portion so as to be introduced into a gap space formed between the perforated pipe and the inner pipe portion. 2. The muffler for an internal combustion engine according to claim 1, wherein the opening portion is formed by making an end portion of the inner pipe portion upstream of exhaust gas into an open end. 3. The inner pipe portion is close to the perforated pipe portion at a predetermined portion of the inner pipe portion on the downstream side of exhaust gas so that the gap is minimized. A muffler for an internal combustion engine according to Item 1 or 2. 4. The muffler for an internal combustion engine according to claim 1, wherein the inner pipe portion is in close contact with the perforated pipe portion at a predetermined position of the inner pipe portion near the downstream side of exhaust gas. . 5. The muffler for an internal combustion engine according to claim 1, wherein the gap is closed at a predetermined position on the downstream side of the exhaust gas. 6. The relative relationship between the outer diameter of the inner pipe portion and the inner diameter of the perforated pipe portion is changed so that the gap becomes gradually narrower from the upstream side toward the downstream side of the exhaust gas. It is set, The claim 1 or 2 characterized by the above-mentioned.
A muffler for an internal combustion engine according to. 7. The relative relationship between the outer diameter of the inner pipe portion and the inner diameter of the perforated pipe portion changes so that the gap becomes gradually narrower from the upstream side toward the downstream side of the exhaust gas. The muffler for an internal combustion engine according to claim 1 or 2, wherein the muffler is set as follows. 8. The relative relationship between the outer diameter of the inner pipe portion and the inner diameter of the perforated pipe portion so that the gap is substantially constant in a predetermined range from the upstream side of the exhaust gas and is narrowed at the terminal end portion. The muffler for the internal combustion engine according to claim 1 or 2, wherein: 9. A perforated pipe provided between an inlet and an outlet of an exhaust fluid and having a plurality of small holes on its side surface, and a side surface of the perforated tube is hermetically sealed and communicates with the small hole. A space forming chamber, and an inner pipe portion having a predetermined length provided inside the perforated pipe and forming a gap space with the perforated pipe, wherein the gap near the inlet is provided. A muffler for an internal combustion engine, wherein the clearance space closer to the outlet is narrower than the space. 10. A perforated pipe provided between an inlet and an outlet of an exhaust fluid and having a plurality of small holes on its side surface, and a side surface of the perforated tube is hermetically sealed and communicates with the small hole. A chamber that forms a space, and an inner pipe portion that is formed of a pipe of a predetermined length provided inside the perforated pipe and that forms a gap space between the perforated pipe and
A muffler for an internal combustion engine, wherein the clearance space near the inlet is opened in the perforated pipe, and the clearance space near the outlet is closed. 11. A perforated pipe provided between an inlet and an outlet of an exhaust fluid and having a plurality of small holes on a side surface, and a side surface of the perforated tube is hermetically sealed and communicates with the small hole. A chamber forming a space, and a pipe having a predetermined length provided inside the perforated pipe, and the diameter of the pipe end portion near the outlet is larger than the diameter of the pipe end portion near the inlet. A muffler for an internal combustion engine, which has an inner pipe section that is open. 12. A perforated pipe provided between an inlet and an outlet of an exhaust fluid and having a plurality of small holes on its side surface, and a side surface of the perforated tube is hermetically sealed and communicates with the small hole. A first chamber forming a space, and an inner tube of a predetermined length inserted inside the perforated tube,
A gap is formed between the perforated pipe and the inner pipe, and the outer diameter of the inner pipe is relative to the inner diameter of the perforated pipe so that the gap is narrower toward the outlet than toward the inlet. A muffler for an internal combustion engine, comprising an inner pipe portion that is changing dynamically and a second chamber that communicates with the first chamber via a communication pipe. 13. A first perforated pipe, which is provided between an inlet and an outlet of the exhaust fluid and has a plurality of small holes on a side surface, and a side face of the perforated pipe that is hermetically sealed. A first chamber forming a space communicating with the hole, and an inner tube of a predetermined length inserted inside the perforated tube,
A gap is formed between the perforated pipe and the inner pipe, and the outer diameter of the inner pipe is relative to the inner diameter of the perforated pipe so that the gap is narrower toward the outlet than toward the inlet. Between the inlet pipe and the outlet for introducing the exhaust fluid, and
A second perforated tube which is provided before or after the perforated tube and has a plurality of small holes on its side surface, and the side surface of the second perforated tube is hermetically sealed, and the small hole of the second perforated tube A muffler for an internal combustion engine, comprising a second chamber that forms a space communicating with the interior of the space, and that houses a sound absorbing material in the space. 14. An inlet for introducing exhaust fluid,
A muffler body having an internal space and an outlet for leading out the exhaust fluid to the outside, and a perforated tube having a plurality of small holes on its side surface, and is housed inside the muffler body. The space inside the pipe communicates with the inlet and the outlet, guides the exhaust fluid introduced from the inlet to the outlet, and through the plurality of small holes into the space inside the muffler body. A perforated pipe portion for diffusing and an inner pipe having a predetermined length inserted inside the perforated pipe, a gap is formed between the inner pipe and the perforated pipe, and the gap is formed in a portion near the downstream of exhaust gas. A muffler for an internal combustion engine, comprising an inner pipe portion including a portion which is in close contact with the perforated pipe portion so as to be minimized. 15. An inlet for introducing exhaust fluid,
A muffler body having an internal space and an outlet for leading out the exhaust fluid to the outside, and a perforated tube having a plurality of small holes on its side surface, and is housed inside the muffler body. The space inside the pipe communicates with the inlet and the outlet, guides the exhaust fluid introduced from the inlet to the outlet, and through the plurality of small holes into the space inside the muffler body. A perforated pipe portion for diffusing and an inner pipe having a predetermined length inserted inside the perforated pipe, a gap is formed between the inner pipe and the perforated pipe, and the gap is formed in a portion near the downstream of exhaust gas. A muffler for an internal combustion engine, comprising an inner pipe portion including a portion relatively close to the perforated pipe portion so as to be minimized. 16. An inlet for introducing exhaust fluid,
A muffler body having an internal space and an outlet for leading out the exhaust fluid to the outside, and a perforated tube having a plurality of small holes on its side surface, and is housed inside the muffler body. The space inside the pipe communicates with the inlet and the outlet, guides the exhaust fluid introduced from the inlet to the outlet, and through the plurality of small holes into the space inside the muffler body. A perforated pipe portion for diffusing and an inner pipe of a predetermined length inserted inside the perforated pipe, a gap is formed between the inner pipe and the perforated pipe, and an end of the inner pipe upstream of exhaust gas. An inner pipe portion including a portion that is open and allows the exhaust fluid to enter the gap from the open end, and that is in close contact with the perforated pipe portion so that the gap is minimized at a position near the downstream of exhaust gas; Muffler for internal combustion engine with. 17. An inlet for introducing exhaust fluid,
A muffler body having an internal space and an outlet for leading out the exhaust fluid to the outside, and a perforated tube having a plurality of small holes on its side surface, and is housed inside the muffler body. The space inside the pipe communicates with the inlet and the outlet, guides the exhaust fluid introduced from the inlet to the outlet, and through the plurality of small holes into the space inside the muffler body. A perforated pipe portion for diffusing and an inner pipe of a predetermined length inserted inside the perforated pipe, a gap is formed between the inner pipe and the perforated pipe, and an end of the inner pipe upstream of exhaust gas. An inner portion that is open and allows the exhaust fluid to enter the gap from the open end, and that includes a portion relatively close to the perforated pipe portion so that the gap is minimized at a location near the downstream of the exhaust. A muffler for an internal combustion engine with a pipe section. 18. An inlet for introducing exhaust fluid,
A muffler body having at least two partitioned chambers and a discharge port for discharging the exhaust fluid to the outside, and a porous structure having a plurality of small holes on a side surface in a range corresponding to at least one of the chambers. The pipe has a pipe, is housed inside the muffler body, and the space inside the pipe communicates with the inlet and the outlet, and guides the exhaust fluid introduced from the inlet to the outlet. A porous tube part for diffusing into the at least one chamber inside the muffler body through the plurality of small holes, and an inner tube of a predetermined length inserted inside the porous tube, the inner tube and the porous tube A gap is formed between the pipe and a predetermined portion of the inner pipe on the upstream side of the exhaust gas is opened to allow the exhaust fluid to enter the gap through the opening, and the gap is formed on the downstream side of the exhaust gas. To be the smallest Muffler for an internal combustion engine equipped with an inner tube portion which includes a portion relatively close to the perforated pipe section. 19. The muffler for an internal combustion engine according to claim 1, wherein a sound absorbing member is housed in the chamber.