JP2005207331A - Exhaust muffler apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust muffler apparatus capable of not only improving exhaust gas purification efficiency but also effectively reducing exhaust noise. <P>SOLUTION: An exhaust muffler apparatus body 10 provided with an exhaust gas purification means 17 inside is divided into a first chamber A, a second chamber B and a third chamber by a first partition 14 and a second partition 15. A branch pipe portion 23a is provided at an inlet port of the second chamber B partitioned by the first partition 14 and the second partition 15 and an aperture portion is provided at an outlet port of the second chamber to form a Helmholtz resonance element with the second chamber B, the branch pipe portion 23a and the aperture portion 24, so that vibration due to a specific frequency component contained in the exhaust noise is reduced by the resonance element. A sub-muffler apparatus 110 is disposed on the downstream side of the exhaust muffler apparatus body 10, thereby reducing the exhaust gas noise also in the sub-muffler apparatus 110. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an exhaust muffler device having an exhaust purification means housed in an exhaust muffler device body.

  In general, exhaust purification means as an apparatus for post-processing exhaust gas of an engine, for example, a diesel engine, has a form such as a catalyst monolith or a particulate filter. The purification efficiency of such exhaust purification means is high in a high-temperature atmosphere. It is known that it is effective to operate with this. For this reason, it is required to develop an exhaust muffler apparatus in which the exhaust purification means is installed in a high temperature atmosphere inside the exhaust muffler body.

  As an exhaust muffler apparatus in which a purifying means made of a catalyst monolith or a particulate filter is housed in an exhaust muffler body, for example, a technique described in Japanese Patent Application Laid-Open No. 2002-21431 (hereinafter referred to as “prior art”) is known. That is, in this prior art, as shown in FIG. 9, the main body of the exhaust muffler device is divided into a first chamber 3, a second chamber 4, and a third chamber 5 by two first partitions 1 and 2, and both The purifying means 6 is attached to the second chamber 4 in two upper and lower stages so as to straddle between the partition walls 1 and 2. The exhaust muffler body has an inlet pipe 7 communicating with the first chamber 3, an inner pipe 8 (two in the vertical direction) straddling the second chamber 4 and the third chamber 5, and a dimension longer than the inner pipe 8. The outlet pipe 9 is provided so as to penetrate the exhaust muffler main body. The inner pipe 8 and the outlet pipe 9 have holes 8a and 9a communicating with the second chamber 4 and the third chamber 5, respectively, and the second partition 4 and the second chamber 4 and the third chamber 5 communicate with each other. Thus, the holes 2a are respectively formed.

  As described above, in the above prior art, the exhaust gas from the engine is introduced into the first chamber 3 from the inlet pipe 7 and expands, and then the exhaust gas is purified by flowing through the purification means 6, so that the third chamber 5 Flows into and expands. The exhaust gas discharged into the third chamber 5 flows into the inner pipe 8 and is discharged into the second chamber 2 through the hole 8a, so that noise in a predetermined sound range is silenced. The exhaust gas flowing into the second chamber 2 is sucked into the hole (a hole facing the second chamber 4) 9a of the outlet pipe 9, introduced into the outlet pipe 9, and discharged to the outside. Yes.

  However, in the above-described prior art, not only the first chamber 3 and the third chamber 5 but also the second chamber 4 around the purifying means 6 is used as an expansion chamber for expanding the volume of the exhaust gas. This is another factor of the exhaust noise source, although exhaust gas is flown into these chambers 3, 4 and 5 to diffuse and narrow down and make sounds interfere with each other to attenuate exhaust noise. Since noise reduction by a structure provided with a resonance chamber focusing on the flow of exhaust sound is not intended, the exhaust sound attenuation effect in a specific frequency range in a certain exhaust muffler device has a certain limit.

  As a technique for attenuating exhaust noise by providing a resonance chamber focusing on the flow of such exhaust sound, for example, as described in JP-A-10-274027, a resonance chamber and a branch pipe communicating with the resonance chamber are used. It is conceivable to design an exhaust muffler device that obtains the maximum volume reduction near the resonance frequency by utilizing the principle of the Helmholtz resonator. The technique described in Japanese Patent Laid-Open No. 10-274027 is merely a structure in which a Helmholtz type resonance device is provided in the middle of the exhaust pipe, and the exhaust purification means is housed in the exhaust muffler device body. Thus, it is not a technique that silences the exhaust sound in a specific frequency range unique to the exhaust muffler device.

JP 2002-215151 A Japanese Patent Laid-Open No. 10-274027

  The present applicant has researched and developed an exhaust muffler device that not only improves exhaust purification efficiency but also can effectively reduce exhaust noise in an exhaust muffler device having exhaust purification means incorporated in the exhaust muffler body. I went. As a result, in order to solve the problems of the conventional device described in the publication of the above-mentioned patent document 1, by applying the principle of the Helmholtz resonator described in the publication of the above-mentioned patent document 2, The discovery that it is possible to enhance the noise-reducing effect on the sound flow of the engine, as well as improving the exhaust purification efficiency, and simultaneously developing an exhaust muffler device that can smoothly reduce exhaust noise did it. An object of the present invention is to provide such an exhaust muffler device.

  In order to solve the above problems, the following measures are taken in the present invention. That is, the invention according to claim 1 is an exhaust muffler device, wherein the exhaust muffler device body is formed by closing the cylindrical outer shell both end openings with the upstream end plate and the downstream end plate. A first partition and a second partition provided inside the apparatus main body, a first chamber as an expansion chamber partitioned by the downstream end plate and the first partition, the first partition and the second partition A second chamber as a partitioned resonance chamber, a third chamber as an expansion chamber partitioned by the second partition wall and the upstream end plate, and the exhaust muffler main body are housed in an upstream side, Exhaust gas purifying means having a downstream side opened to the first chamber in an exhaust inlet pipe provided on the upstream side end plate, and one end opened to the first chamber and the other end punched through the second chamber Through the third A first communication pipe that communicates with the first communication pipe, and a first communication pipe that is arranged in parallel with the first communication pipe and penetrates the second chamber, and has one end opened in the first chamber and the other end opened in the third chamber. Two communication pipes, a branch pipe provided in the second partition so as to protrude into the third chamber with a dimension of a predetermined length, and allowing the flow of sound from the third chamber to the second chamber, A hole formed in the second partition wall for allowing sound to flow from the second chamber to the third chamber, and an exhaust outlet pipe provided in the upstream end plate for discharging the exhaust from the third chamber to the outside It was characterized by comprising.

  According to the first aspect of the present invention, exhaust gas discharged from a diesel engine or gasoline engine or the like flows into the exhaust muffler body from an exhaust inlet pipe, and has an exhaust purification structure having a honeycomb structure such as a diesel particulate filter or a catalyst monolith. Circulate means. When the exhaust gas passes through the exhaust gas purification means, harmful components in the exhaust gas are captured and purified, and then diffused and expanded in the first chamber. Most of the exhaust gas flow in the first chamber is squeezed into the second communication pipe (a pipe having both ends open but no punch holes are formed), and then flows into the third chamber. It is discharged from the exhaust outlet pipe to the outside. At this time, since the second communication pipe performs air column resonance, a vibration component equal to the resonance frequency is attenuated by interference. Further, a part of the flow of the exhaust gas in the first chamber is squeezed into the first communication pipe and flows into the third chamber from the punch hole facing the third chamber and diffuses and expands, and then the exhaust outlet pipe It will be discharged from. On the other hand, focusing on the flow of exhaust sound in the exhaust gas in the third chamber (not the flow of exhaust gas), the flow of exhaust sound including various frequency components is provided so as to protrude into the second partition wall. After propagating from the tube into the second chamber and entering the second chamber, it further propagates from the hole provided in the second partition to the third chamber. Thus, after the flow of the exhaust sound enters the third chamber from the branch pipe and then propagates from the hole to the third chamber, the second chamber functions as a Helmholtz resonance chamber. Component, that is, a component in a specific frequency range of the exhaust sound is attenuated (silenced), and the exhaust sound is silenced in the second chamber.

  Further, the invention according to claim 2 relates to the invention according to claim 1, wherein an extension pipe projecting from the branch pipe to the second chamber is provided to close a pipe end of the extension pipe, and A punch hole is formed in the peripheral wall in the second chamber.

According to the second aspect of the present invention, since the punch hole is formed in the extension pipe provided to extend from the branch pipe, the exhaust gas flowing into the second chamber from the punch hole is expanded and diffused in the second chamber. The exhaust gas is also reduced in the second chamber.

The invention according to claim 3 relates to the exhaust muffler device according to claim 1 or 2, characterized in that the open end of the second communication pipe in the third chamber is extended to the vicinity of the exhaust outlet pipe. And

In the invention according to claim 3, the open end of the second communication pipe (no punch hole is provided) is provided in the third chamber close to the exhaust outlet pipe, that is, the upstream end plate Since the exhaust gas in the first chamber is directly guided to the third chamber through the second communication pipe, the first chamber can be discharged from the exhaust outlet pipe. The exhaust gas in the first chamber flows into the first communication pipe so as to generate a negative pressure.

  According to a fourth aspect of the present invention, there is provided the exhaust muffler device according to any one of the first to third aspects, wherein an exhaust pipe downstream of the exhaust muffler main body is formed of an inner cylinder and an outer cylinder. The inner cylinder of the sub-muffler device is communicated, the inner cylinder is provided with a number of punch holes having a diameter of about 4 mm, and the chambers in the inner and outer cylinders are filled with a sound absorbing material having a density of about 120 g / cm3. It is characterized by.

  In the invention according to claim 4, when exhaust gas flows through the sub-muffler device provided in the exhaust pipe downstream of the exhaust muffler device main body, the exhaust gas diffuses and flows from the punch hole of the inner cylinder into the chamber formed by both the inner and outer cylinders. The noise is absorbed by a sound absorbing material such as glass wool.

The invention according to claim 5 relates to the exhaust muffler device according to any one of claims 1 to 4, and is directed to the exhaust purification unit between the exhaust inlet pipe and the exhaust purification unit. Accordingly, a trumpet-shaped tube having an enlarged exhaust cross-sectional area is provided.

According to the fifth aspect of the present invention, since the exhaust gas is directly supplied from the exhaust inlet pipe to the exhaust gas purification means via the trumpet-like pipe, the purification efficiency is maintained because the purification action is performed while the exhaust gas purification means is kept at a high temperature. In addition, when the exhaust gas flows through the trumpet-like tube, the exhaust gas is expanded and diffused, which is advantageous in reducing exhaust noise.

  According to the first aspect of the present invention, the exhaust gas that has passed through the exhaust purification means and expanded and diffused into the first chamber is discharged straight from the exhaust outlet pipe through the second communication pipe without applying resistance as much as possible. The vibration component equal to the resonance frequency by the air column resonance of the second communication pipe can be attenuated by interference. On the other hand, by providing a branch pipe and a hole in the second partition wall and forming the second chamber so as to function as a Helmholtz resonator, the resonance effect can be exerted. Among various frequency components contained in the exhaust gas propagated from the branch pipe to the second chamber, exhaust sound waves including a specific frequency component near the resonance frequency are attenuated in the second chamber. Therefore, the overall silencing effect is achieved by the silencing action in the first chamber as the expansion chamber, the third chamber, and the second chamber as the resonance chamber, and the silencing action due to the air column resonance of the second communication pipe. The exhaust muffler device excellent in the exhaust gas can be obtained, and the exhaust gas exhausted in the engine exhaust system flows into the exhaust gas purification means from the exhaust inlet pipe, so that the temperature of the exhaust gas is reduced. The exhaust gas purification function can be maintained and enhanced in a suppressed state, and an effect of realizing a compact exhaust muffler device is achieved.

  According to the second aspect of the present invention, since the punch hole is formed in the extension pipe provided so as to extend to the branch pipe, the exhaust gas flowing into the second chamber from the punch hole suddenly flows in the second chamber. Since the pressure fluctuation is absorbed by expanding and diffusing, the second chamber has the effect of exerting a silencing action.

According to the third aspect of the present invention, since the open end of the second communication pipe (no punch hole is provided) is located in the vicinity of the exhaust outlet pipe in the third chamber, the exhaust gas can be circulated. Exhaust noise can be reduced in a state in which the resistance is lowered, that is, in the state where an increase in the back pressure against the engine output is avoided, and the exhaust is discharged from the exhaust outlet pipe directly from the second communication pipe through the third chamber. Therefore, the negative pressure generated in the third chamber is increased. Therefore, the flow rate of the exhaust gas flowing from the first chamber into the first communication pipe increases, and the exhaust gas expands and diffuses from the punch hole of the first communication pipe to the third chamber and is discharged. There is an effect that the exhaust noise of the flow of exhaust gas can be reduced smoothly.

  According to the fourth aspect of the present invention, when exhaust gas flows through the sub-muffler device provided in the exhaust pipe downstream of the exhaust muffler device main body, the exhaust gas diffuses and diffuses from the punch hole of the inner cylinder to the chamber formed by the inner and outer cylinders. Therefore, sound is absorbed by a sound absorbing material such as glass wool, and the noise of exhaust gas can be reduced even by the sub-muffler device.

According to the fifth aspect of the present invention, since the exhaust gas is directly flown into the exhaust gas purification means via the trumpet-shaped pipe from the exhaust gas inlet pipe, the purification effect is performed while the exhaust gas purification means is kept at a high temperature. In addition, the exhaust gas is expanded and diffused even when the exhaust gas flows through the trumpet-like tube, so that it is advantageous in reducing the exhaust noise.

An embodiment according to the exhaust muffler apparatus of the present invention will be described in detail with reference to FIGS.
As shown in FIG. 1, the exhaust system in the present embodiment includes an exhaust muffler device 10 provided in an exhaust pipe 100 of a diesel engine and a sub muffler device 110 provided on the downstream side thereof.

First, the exhaust muffler device body 10 will be described. That is, as shown in FIG. 2, the exhaust muffler main body 10 is made of, for example, stainless steel in consideration of corrosion resistance, and is open at both ends of a cylindrical outer shell 11 having a box-like appearance. Is closed by an upstream end plate (hereinafter referred to as “left end plate”) 12 and a downstream end plate (hereinafter referred to as “right end plate”) 13. The left end plate 12 is filled between the inner plate 12a and the outer plate 12b with glass wool 12c, which is a material effective for sound absorption and silencing. Similarly, the right end plate 13 also has its inner plate 13a and outer plate 13b. Between them, glass wool 13c is filled. Further, as the inner plates 12a and 13a of the left and right end plates 12 and 13, for example, a concave punching process with a pitch interval of 3.5 and an inner diameter φ2 is performed, and the silencing effect by the glass wool 12c and 13c is exhibited. I can do it.

  A first partition 14 and a second partition 15 are provided in the exhaust muffler main body 10 so as to partition the internal chamber at a predetermined interval from the right with respect to FIG. 1, and the right end plate in order from the right. A first chamber A as an expansion chamber partitioned by a first partition wall 14 and a first partition wall 14; a second chamber B as a resonance chamber partitioned by a first partition wall 14 and a second partition wall 15; A third chamber C as an expansion chamber partitioned by the left end plate 12 is formed.

  Further, exhaust purification means 17 is provided across the first partition wall 14 and the second partition wall 15 in the exhaust muffler main body 10, and left via a trumpet-shaped tube 18 whose cross-sectional area expands toward the downstream side. Connected (welded) to an exhaust inlet pipe 16 penetratingly supported by the end plate 12.

  The exhaust purification means 17 is, for example, a purification means in the form of a catalyst monolith, which has a porous honeycomb structure, and carries a catalyst appropriately selected from various catalysts such as an oxidation catalyst or a reduction catalyst. It promotes the oxidation or reduction reaction of harmful substances contained in the exhaust gas.

  On the other hand, above the exhaust purification means 17, a first communication pipe 21 (see FIG. 2) and the first communication pipe 10 are arranged substantially parallel to the longitudinal direction of the exhaust muffler device body 10. The second communication pipe 22 (see FIG. 3) is supported (welded) by the first partition wall 14 and the second partition wall 15 so as to penetrate the second chamber B, and the first chamber A and the third chamber. It is trying to communicate with C. That is, the first communication pipe 14 opens on the first chamber A side, the pipe end is closed in the third chamber C, and communicates with the third chamber C via a number of punch holes 21a formed in the peripheral wall. ing. Further, the second communication pipe 22 is a pipe having no punch hole, and the pipe end on the third chamber C side is infinitely close to the inner plate 12a of the left end plate 12 as shown in FIG. The exhaust gas that opens and flows into the third chamber C from here flows into the exhaust outlet pipe 19 provided in the left end plate 12 immediately. The exhaust outlet pipe 19 is connected to the exhaust pipe 100 (see FIG. 1) and communicates with the sub-muffler device 110.

On the other hand, a third communication pipe 23 disposed substantially parallel to the first and second communication pipes 21 and 22 is supported (welded) on the first partition wall 14 and the second partition wall 15. As shown in FIG. 2, the third communication pipe 23 includes a branch pipe part 23 a that protrudes to the left from the second partition 15, that is, the third chamber C side with a predetermined length, and a branch pipe part. 23a, which extends into the second chamber B at the center, and has an extension tube portion 23b whose tube end is closed, and the peripheral wall of the extension tube portion 23b has a number of punch holes 23c leading to the second chamber B, As a result, the sound flow of the exhaust gas flows from the third chamber C into the second chamber B via the third communication pipe 23 (propagation). Further, a hole 24 having an inner diameter substantially equal to the outer diameter of each of the communication pipes 21 to 23 is provided above the second partition wall 15, and the sound of the exhaust gas propagates from the second chamber B to the third chamber C. Like that.
Thus, the second chamber B, the branch pipe portion 23a, and the hole portion 24 form a resonance means that uses the principle of the Helmholtz resonator.

  Further, as shown in FIG. 5, a punching metal 25 in which a large number of punch holes are formed is provided on the inner peripheral wall surface of the upper half of the first chamber A, and the end plates 14 and 15 are provided on the back side thereof. In the same manner as the above, the structure is filled with glass wool, which is an appropriate sound absorbing material.

  2 and 3 indicate a support member used for mounting the exhaust muffler main body 10 to an appropriate position (frame) of the vehicle body (for example, a truck), in the longitudinal axis direction of the exhaust muffler main body 10. It is attached to penetrate along. Reference numeral 31 denotes a detent member provided on the left end plate 12 to prevent the mounted exhaust muffler main body 10 from swinging.

  Next, the sub muffler device 110 will be described. That is, the sub-muffler device 110 is an after-muffler for the exhaust muffler device body 10 and is formed of a stainless material like the exhaust muffler device body 10 and the exhaust pipe 100. As shown in FIG. In the vicinity of the tail pipe of the exhaust pipe 100 on the downstream side. The sub muffler device 110 is arranged so as to be matched so that a good silencing effect can be obtained from the exhaust muffler device main body 10.

The sub-muffler device 110 is formed by an inner cylinder 110a and an outer cylinder 110b having a circular cross section, and an expansion chamber 111 is provided between the inner and outer cylinders 110a and 110b. As shown in FIG. 6 (b), the inner cylinder 110a is a punching metal (stainless steel) in which a large number of punch holes 110c having a diameter of about 4 mm are formed, and the expansion chamber 111 has a density of about 120 g / cm 3. A sound absorbing material such as glass wool is filled as shown by hatching.

  Next, the operation of the present embodiment will be described mainly with reference to FIGS. 2 and 3, black arrows indicate the exhaust gas flow direction, and white arrows indicate the direction in which the exhaust sound propagates. That is, the exhaust gas guided from the engine (not shown) to the exhaust inlet pipe 16 flows from the trumpet-shaped pipe 18 to the inside of the exhaust purification means 17, and after the harmful substances contained in the exhaust gas are purified, Since the gas flows into the chamber A after being expanded and diffused, the pressure fluctuation of the exhaust gas is reduced and the noise is reduced. Next, the exhaust gas in the first chamber A is squeezed into the second communication pipe 22 (see FIG. 3) and sent into the interior, and the exhaust sound of the exhaust gas is silenced by this exhaust gas squeezing process. . Since the exhaust gas fed into the second communication pipe 22 is expanded and diffused into the third chamber C from the outlet, the pressure fluctuation of the exhaust gas is reduced and attenuated. Thereafter, the exhaust gas immediately enters the exhaust outlet pipe 19 from the third chamber C and flows to the sub muffler device 110. At the same time, since the second communication pipe 22 has a function of air column resonance, the vibration component of the exhaust sound equal to the air column resonance is attenuated by interference. Therefore, the second communication pipe 22 also has the air column resonance function. A silencing effect is obtained.

On the other hand, the exhaust gas in the first chamber A is squeezed into the first communication pipe 21 and flows into the first communication pipe 21, so that the exhaust noise of the exhaust gas is eliminated even during the squeezing process. Then, in the process in which the exhaust gas expands and diffuses from the punch hole 21a into the third chamber C, the pressure fluctuation of the exhaust gas is reduced, so that the sound is silenced. Thereafter, the exhaust gas in the third chamber C is discharged from the exhaust outlet pipe 19 And flows to the sub-muffler device 110.

On the other hand, focusing on the flow (propagation) of the exhaust sound of the exhaust gas in the third chamber C, the flow of the exhaust sound flows from the branch pipe portion 23a to the second chamber B via the punch hole 23c of the extension pipe portion 23b. A vibration component that propagates and is equal to a specific frequency component in the second chamber B is attenuated by interference, and the sound passes through the hole 24 (see FIG. 3) formed in the second partition wall 15 and the sound is transmitted to the third chamber. Even when propagating to C, the vibration component equal to the specific frequency component is attenuated by the interference, so that the exhaust noise is attenuated by this and the noise reduction effect is exhibited.
In addition, since the exhaust gas expands and diffuses into the second chamber B from the punch hole 23c of the extension pipe portion 23b, the pressure fluctuation of the exhaust gas is reduced here, which is effective in reducing noise.

  Further, the exhaust gas discharged from the exhaust muffler device body 10 flows through the exhaust pipe 100 in the middle and is supplied into the sub muffler device 110. When the exhaust gas flows through the sub muffler device 110, the exhaust gas is punched. Since it passes through the hole 110c and flows into the expansion chamber 111 and expands, the exhaust noise is thereby reduced, and the exhaust noise is also reduced by the sound absorption effect of glass wool.

  The present applicant conducted an experiment using the exhaust muffler device body 10 and the sub muffler device 110 according to the above-described embodiment in the case where the most frequently used engine rotation range (economic travel range), for example, a diesel engine was rotated at 1850 rpm. went. As a result, an exhaust sound frequency analysis graph as shown in FIGS. 7 and 8 was obtained. That is, FIG. 7 is a graph obtained by conducting a comparative test on the exhaust muffler device body 10 according to the above embodiment and a muffler device of a conventional structure that is not so, and FIG. 8 shows the sub muffler device 110 according to the above embodiment. The graph which compared the case where it mounts | wears and the case where it does not mount | wear is shown.

As can be seen from FIG. 7, the exhaust noise level in the frequency band of 200 to 500 Hz is significantly higher when the exhaust muffler apparatus body 10 according to the present embodiment is mounted than when the muffler apparatus having the conventional structure is mounted. Further, in FIG. 8, when the sub muffler device 110 is installed, the result that the noise level is reduced in all frequency bands after 160 Hz can be obtained when the sub muffler device 110 is installed. As can be seen from these experimental results, according to the present embodiment, the noise of the exhaust gas discharged from the engine can be greatly reduced and silenced by using the exhaust muffler device body 10. Further, mounting the sub muffler device 110 downstream of the exhaust muffler device body 10 has an advantageous effect of further reducing the noise of the exhaust gas.

As described above, according to the present embodiment, not only the exhaust purification efficiency by the exhaust purification means 17 housed in the exhaust muffler apparatus body 10 can be improved, but also a compact exhaust muffler that is excellent in exhaust noise reduction and silencing effects. An apparatus can be obtained, and by mounting the sub muffler device 110 as an after muffler on the downstream side, the exhaust system as a whole has the effect of further enhancing the exhaust noise and the silencing effect.

The embodiment of the present invention has been described in detail above with reference to the drawings. However, the specific configuration is not limited to this embodiment, and even if there is a design modification or the like without departing from the gist of the present invention. Included in the invention.
For example, in the above-described embodiment, the catalyst monolith has been described as the exhaust purification unit 17, but instead, it can also be applied to a particulate filter of an exhaust system of a diesel engine. In this case, the particulate filter uses, for example, a purification means such as a so-called wall flow honeycomb filter having an exhaust gas passage made of a sintered body of porous silicon carbide or cordierite arranged in a large number of honeycombs. But you can.

  Moreover, in the said embodiment, the extension pipe part 23b provided with the punch hole 23c is formed as the 3rd communication pipe 23, and the Helmholtz type resonator of the 2nd chamber B, the branch pipe part 23a, and the hole part 24 is comprised. Although the resonance means utilizing the principle is used, the length of the branch pipe part 23a and the volume of the second chamber B are appropriately set without depending on the form of the communication pipe 23, that is, without providing the extension pipe part 23b. You may make it set. In this way, it is a matter of course that tuning is performed so as to obtain exhaust sound attenuation and silencing characteristics suitable for the exhaust muffler device.

It is a system configuration diagram of an exhaust system showing a schematic configuration of an exhaust system in which an exhaust muffler apparatus body according to a first embodiment of the present invention is installed. It is a longitudinal cross-sectional view in the center of an exhaust muffler device (main muffler device). It is the longitudinal cross-sectional view which looked at FIG. 2 from the back side. FIG. 3 is a cross-sectional view taken along line 3-15 in FIG. FIG. 5 is a transverse cross-sectional view taken along line 5-5 in FIG. 2. The sub muffler apparatus provided in the exhaust pipe of the downstream of the said exhaust muffler apparatus is shown, (a) is the longitudinal cross-sectional view, (b) is the expansion | deployment top view which reduced and showed the inner cylinder which is a component of a sub muffler . It is a graph which shows the exhaust sound frequency analysis which compared the exhaust muffler apparatus main body with the conventional product. It is a graph which shows the exhaust sound frequency analysis which compared with the case where the sub muffler apparatus is provided, and the case where it is not provided. It is sectional drawing of a conventional apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Exhaust muffler apparatus main body 11 Outer shell 12 Left end plate 13 Right end plate 14 First partition 15 Second partition 16 Exhaust inlet pipe 17 Exhaust purification means 18 Trumpet-shaped pipe 19 Exhaust outlet pipe 21 First communication pipe 21a Punch hole 22 Second communication pipe 23 Third communication pipe 23a Branch pipe part 23b Extension pipe part 23c Punch hole 24 Hole part 100 Exhaust pipe 110 Sub-muffler device 110c Punch hole 111 Expansion chamber A First chamber B Second chamber C Third chamber

Claims (5)

  In an exhaust muffler main body formed by closing both ends of the cylindrical outer shell with an upstream end plate and a downstream end plate, a first partition and a second partition provided inside the exhaust muffler main body, and the downstream A first chamber as an expansion chamber partitioned by a side end plate and the first partition; a second chamber as a resonance chamber partitioned by the first partition and the second partition; and the second partition A third chamber as an expansion chamber partitioned by the upstream end plate and the exhaust muffler device main body are accommodated in the exhaust muffler device main body, and an upstream side is provided in the exhaust end pipe provided in the upstream end plate. An exhaust gas purifying means opened in a chamber, a first communication pipe penetrating the second chamber, having one end opened in the first chamber and the other end communicated with the third chamber via a punch hole; Arranged in parallel with the first communication pipe And a second communication pipe having one end opened to the first chamber and the other end opened to the third chamber, and protrudes into the third chamber with a predetermined length. And a branch pipe provided in the second partition wall for flowing a sound flow from the third chamber into the second chamber, and a sound flow formed in the second partition wall from the second chamber to the third chamber. An exhaust muffler device, comprising: a hole portion through which the air flows in; and an exhaust outlet pipe that is provided in the upstream end plate and discharges the exhaust of the third chamber to the outside. An extension pipe projecting from the branch pipe to the second chamber is provided, a pipe end of the extension pipe is closed, and a punch hole is formed in a peripheral wall of the extension pipe in the second chamber. The exhaust muffler device according to 1. The exhaust muffler device according to claim 1 or 2, wherein an open end of the second communication pipe in the third chamber is extended to the vicinity of the exhaust outlet pipe. The exhaust pipe downstream of the exhaust muffler apparatus main body is connected to the inner cylinder of the sub-muffler device formed by an inner cylinder and an outer cylinder, and a plurality of punch holes having a diameter of about 4 mm are formed in the inner cylinder, and The exhaust muffler device according to any one of claims 1 to 3, wherein the chambers in the inner and outer cylinders are filled with a sound absorbing material having a density of about 120 g / cm3. 5. A trumpet-shaped pipe whose exhaust flow cross-sectional area increases as it goes to the exhaust purification means is provided between the exhaust inlet pipe and the exhaust purification means. The exhaust muffler device according to the item.

Images