JP2005140059A - Exhaust muffler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain and enhance purifying function by introducing exhaust gas into a purifying means without lowering the temperature of exhaust gas while maintaining noise eliminating function. <P>SOLUTION: An exhaust muffler body 10 is formed by a cylindrical shell 11 and a pair of end plate members 12, 13 for closing the shell 11 at both ends. In the exhaust muffler body 10, an exhaust inlet pipe 16 is provided storing the purifying means 17 in such a manner that the purifying means 17 exists in the exhaust muffler body 10. Thus, exhaust gas flowing into the exhaust inlet pipe 16 is all distributed into the purifying means 17 in just proportion. Expansion chambers A, B, C are formed in the exhaust muffler body 10 facing to the downstream side of the purifying means 17 so that the exhaust air after distributed into the purifying means 17 is expanded in the expansion chambers A, B, C and then discharged from an exhaust outlet pipe 22 provided in the exhaust muffler body. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an exhaust muffler having a form in which a purification means is housed inside an exhaust muffler body.

  In general, purification means as a device for post-processing exhaust gas of an engine, for example, a diesel engine, includes a catalyst monolith or a particulate filter. It is effective to operate the purification means in a high-temperature atmosphere. It is. For this reason, it is required to develop an exhaust muffler in which the purification means is housed in the exhaust muffler body.

  For example, Japanese Patent Application Laid-Open No. 2002-21531 is known as an exhaust muffler technique in which a purification means including a catalyst monolith or a particulate filter is housed in an exhaust muffler body. As shown in FIG. 5, the gazette disclosed in this publication divides an exhaust muffler body into two spaces, a first space 3, a second space 4, and a third space 5, by two first partition walls 1 and a second partition wall 2. The purifying means 6 is attached to the second space 4 so as to straddle between 1 and 2 in two stages. Further, the exhaust muffler main body has an inlet pipe 7 communicating with the first space 3, an inner pipe 8 (two in the vertical direction) straddling the second space 4 and the third space 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 space 4 and the third space 5, respectively. The second space 4 and the third space 5 are also communicated with the second partition wall 2. Thus, the holes 2a are respectively formed.

  In the exhaust muffler having such a configuration, the exhaust gas from the engine is introduced into the first space 3 from the inlet pipe 7 and expands, and then flows through the purification means 6 to purify the exhaust gas and flow into the third space 5. Then expand. The exhaust gas flowing into the third space 5 flows into the second space 2 via the hole 8a of the inner pipe 8 and the hole 2a of the second partition wall 2 and expands. The exhaust gas flowing into the second space 2 is sucked into the hole (a hole facing the second space 4) 9a of the outlet pipe 9, introduced into the outlet pipe 9, and then discharged to the outside. Yes.

JP 2002-215151 A

  However, in the thing of the said patent document 1, not only the 1st space 3 and the 3rd space 5 but the 2nd space 4 is utilized for the flow path of exhaust gas as an expansion chamber which expands the volume of exhaust gas. Thus, although the noise reduction function is increased, the exhaust gas flowing into the purification means 6 is once introduced into the first space 3 and diffused and expanded until it flows into the purification means 6 from the inlet pipe 7. Therefore, since the exhaust gas flows into the purification means 6 in a state where the temperature of the exhaust gas is lowered, there is a problem that the exhaust purification efficiency such as the catalytic function in the purification means 6 and the collection rate of the particulate filter is significantly reduced. is there. In order to solve such problems, it is an object (problem) of the present invention to provide an exhaust muffler that maintains and improves the purification function of the purification means while maintaining the muffling function. .

  In order to solve the above problems, the following measures are taken in the present invention. That is, the invention described in claim 1 is an engine exhaust muffler body formed by a cylindrical outer shell and a pair of end plate members that close both ends of the outer shell, and the exhaust gas of the engine is mounted on the end plate. An exhaust inlet pipe for receiving the exhaust gas is provided. Purifying means is accommodated in the exhaust inlet pipe so that the purifying means is located inside the exhaust muffler main body, and all exhaust flowing into the exhaust inlet pipe is not excessive or deficient. An expansion chamber in which exhaust gas diffuses and expands is formed at a position facing the downstream side of the purification means, and the exhaust gas after flowing through the purification means is expanded in the expansion chamber. Then, the exhaust muffler body is configured to be discharged from an exhaust outlet pipe provided on an end plate of the exhaust muffler body.

  In the first aspect of the invention, exhaust gas discharged from an engine such as a diesel engine or a gasoline engine is guided to an exhaust inlet pipe and flows into the exhaust muffler body, and a diesel particulate filter housed in the exhaust inlet pipe or The purification means having a honeycomb structure such as a catalyst monolith does not diffusely expand into the space in the exhaust muffler body, and the entire flow rate of the exhaust gas flows through the purification means. The exhaust gas after passing through the purification means is diffused and expanded in the expansion chamber inside the exhaust muffler body, and is discharged to the outside from the exhaust outlet pipe. For this reason, the exhaust gas flowing into the exhaust inlet pipe from the engine exhaust pipe flows into the purification means, so that the exhaust gas temperature does not decrease and the exhaust purification function can be maintained and enhanced. Since the exhaust gas after passing through the purification means is expanded and silenced in the expansion chamber, the exhaust noise silencing function can be exhibited.

  According to a second aspect of the present invention, there is provided the exhaust muffler according to the first aspect, wherein the expansion chamber formed in the exhaust muffler main body is exhausted by a partition that blocks the flow of the exhaust gas inside the exhaust muffler main body. The first space, the second space, and the third space communicating with the exhaust outlet pipe are formed in order from the upstream side of the exhaust gas after diffusing and expanding the exhaust gas after passing through the purification means, and the first space and the first space Two spaces communicate with each other through a first communication pipe, and the first space, the second space, and the third space communicate with each other through a second communication pipe.

  According to the second aspect of the present invention, the expansion chamber formed in the internal space of the exhaust muffler main body is partitioned into three spaces of the first, second, and third spaces by the partition walls, and the first space to the first space. The exhaust gas flowing into the communication pipe flows out in the second space and diffuses and expands. On the other hand, the exhaust gas flowing into the second communication pipe from the first space flows out in the third space and diffuses and expands. At this time, the exhaust gas flows out from the first communication pipe into the second space in the second space. The exhaust gas is sucked into the second communication pipe by the suction negative pressure generated by the flow of the exhaust gas flowing inside the second communication pipe, flows inside the second communication pipe, and then flows out into the third space. It will diffuse and expand. In this way, the expansion chamber is divided into the three partitions and formed into three spaces, and the exhaust gas is expanded and silenced in each expansion chamber, so that the effect of suppressing the exhaust noise of the exhaust gas can be enhanced.

  Further, the invention according to claim 3 relates to the exhaust muffler according to claim 1 or 2, wherein in the first communication pipe and the second communication pipe, their upstream ends are opened to the first space, and While the downstream end is closed, a hole through which exhaust gas flows is provided on the peripheral side surfaces of the first communication pipe and the second communication pipe.

  In the third aspect of the invention, in the second space, exhaust gas flows in and out through the holes provided in the respective peripheral side surfaces of the first communication pipe and the second communication pipe. That is, since the exhaust gas flowing out from the hole of the first communication pipe into the second space flows into the second communication pipe from the hole of the second communication pipe, the exhaust gas of the first communication pipe and the second communication pipe By appropriately tuning and setting the size, number, etc. of the holes formed in the peripheral side surface, the exhaust noise of the exhaust gas flowing through the first communication pipe and the second communication pipe interferes, and a predetermined sound range is obtained. The frequency can be lowered and the sound pressure can be effectively reduced.

  According to the first aspect of the present invention, the exhaust gas flowing into the exhaust inlet pipe from the engine exhaust pipe flows into the purification means as it is, so that the internal energy of the exhaust gas temperature is retained. Exhaust gas flows through the purification means. For this reason, the purification means will be maintained at a high temperature, and the exhaust purification function can be maintained and enhanced, for example, exhaust purification efficiency in the engine low speed region can be improved, and the exhaust gas after passing through the purification means is Since the sound is expanded and muffled in the expansion chamber, an effect that the noise reduction function of the exhaust noise can be exhibited.

  According to the second aspect of the present invention, the expansion chamber formed in the internal space of the exhaust muffler main body is partitioned into three spaces of the first, second, and third spaces by the partition wall, and the first space The exhaust gas that has flowed into the first communication pipe from the second gas flows out in the second space and diffuses and expands. On the other hand, the exhaust gas flowing into the second communication pipe from the first space flows out in the third space and diffuses and expands. At this time, in the second space in the middle, the exhaust gas flows from the first communication pipe to the second space. The exhaust gas that has flowed out is sucked into the second communication pipe by the suction negative pressure generated by the flow of the exhaust gas flowing inside the second communication pipe, and merged with the exhaust gas flowing inside the second communication pipe. After flowing, it flows out into the third space, expands and is silenced. As described above, since the expansion chamber is divided into three spaces by the partition wall and the space inside the exhaust muffler is effectively used, an effect of enhancing the silencing effect of the exhaust noise of the exhaust gas can be achieved.

  According to the invention described in claim 3, the exhaust gas flowing out from the hole of the first communication pipe into the second space is caused by the negative pressure due to the exhaust flow in the second communication pipe from the hole of the second communication pipe. Since it flows in, the first communication pipe and the second communication pipe are adjusted by appropriately tuning the size and number of holes formed on the peripheral side surfaces of the first communication pipe and the second communication pipe. The exhaust noise of the exhaust gas flowing through the air is interfered, the frequency of a predetermined sound range is lowered, and the sound pressure can be effectively reduced.

  According to the invention described in claim 4, since the exhaust flow cross-sectional area of the exhaust inlet pipe toward the purifying means is expanded in a divergent shape, and the rectifying member is provided at the purifying means inlet end, the divergent shape is increased. The turbulent flow generated in the exhaust gas flowing in while expanding into the enlarged narrow flow path is rectified by the rectifying action of the rectifying member and flows through the purifying means on average, so the utilization efficiency of the purifying means is improved, and as a result, purification. The effect which can improve efficiency is produced.

  An embodiment according to an exhaust muffler of the present invention will be described in detail with reference to FIGS. FIG. 1 is a longitudinal sectional view at the center of the exhaust muffler. The exhaust muffler is made of, for example, stainless steel as a metal material constituting the exhaust muffler, and has a cylindrical outer shell 11 whose outer shape is formed in a box shape, and a pair of right and left that closes the openings at both ends of the outer shell 11 by welding. The exhaust muffler body 10 is formed by forming a space inside the end plate members 12 and 13. The left end plate member 12 is filled between the inner plate 12a and the outer plate 12b with glass wool 12c, which is an effective material for sound absorption and silencing. Similarly, the right end plate member 13 is also separated from the inner plate 13a. Glass wool 13c is filled between the plate 13b. Further, as the inner plates 12a and 13a of the left and right end plate members 12 and 13, for example, a punching process of a concave shape with a pitch interval of 3.5 and an inner diameter φ2 is performed, and a silencing action by a large number of concave portions inside the space is achieved. In effect, the sound absorption by the glass wool 12c synergistically improves the sound absorption and silencing effects.

  A first partition 14 and a second partition 15 are provided in the exhaust muffler main body 10 at a predetermined interval from the right side, and the internal spaces are arranged in order from the right side in the first space A, the second space B, the second space. The three spaces C are partitioned into three spaces.

  The exhaust muffler body 10 is provided with an exhaust inlet pipe 16. The exhaust inlet pipe 16 includes an inlet pipe portion 16a supported by the left end plate member 12, and a storage pipe portion 16b supported by the first partition wall 14 and the second partition wall 15 and storing the purifying means described later. . That is, the inlet pipe portion 16a is supported by penetrating the left end plate member 12, and on the right side thereof, as shown in FIG. 4 (b), the exhaust flow cross-sectional area expands in a divergent shape (rough shape). Part 16c is formed.

  Purifying means 17 is accommodated in the storage pipe portion 16b. The purifying means 17 is, for example, a catalyst monolith, has a porous honeycomb structure, and various catalysts such as an oxidation catalyst and a reduction catalyst. A catalyst selected from the above is supported and promotes oxidation or reduction reaction of harmful substances contained in the exhaust gas. Further, as shown in FIG. 4 (a), a rectifying member 18 having a hole (small hole) 18a formed by punching is provided at a position close to the inlet end of the purifying means 17 so that the exhaust gas is discharged. The flow is rectified so as to flow evenly in the cross section to the purification means 17. The rectifying member 18 may be provided with a rib or the like along the exhaust gas inflow direction on the inner surface of the enlarged portion 16c.

  The exhaust inlet pipe of the exhaust muffler main body 10 includes two short pipes 20 that are first communication pipes and two long pipes 21 that are second communication pipes across the first partition wall 14 and the second partition wall 15. 16 is arranged in parallel. That is, the short tube 20 has a right end opened to the first space A, a left end closed, and a hole 20a communicating with the second space B on the peripheral side surface. In addition, the right end of the long tube 21 is opened so as to communicate with the first space A, and the left end thereof is closed, like the short tube 20, on the circumferential side facing the second space B and the third space C. Holes 21a and 21b through which exhaust gas flows are formed.

  The left end plate member 12 is provided above the exhaust inlet pipe 16 so that an exhaust outlet pipe 22 passes therethrough. The tube end in the third space C of the exhaust outlet tube 22 includes an opening end 22a that is cut obliquely.

  As described above, when the exhaust outlet pipe 22 is attached to the same end plate member 12 on the side where the exhaust inlet pipe 16 is supported, the flow of the exhaust gas flowing in the exhaust muffler body is moved in the direction of the exhaust inlet pipe 16. As a result, the exhaust muffler main body can be formed in a compact size and can be mounted on the vehicle body side.

  Reference numeral 30 in FIG. 1 denotes a support member used for mounting the exhaust muffler main body 10 at an appropriate position of the vehicle body, and is attached so as to penetrate in the longitudinal axis direction of the exhaust muffler main body 10. Reference numeral 31 denotes a detent member provided on the left end plate member 12 to prevent the mounted exhaust muffler main body 10 from swinging.

  The operation of the present embodiment will be described. The arrows in FIG. 1 indicate the flow direction of the exhaust gas. That is, the exhaust gas that has flowed from the engine exhaust pipe (not shown) to the exhaust inlet pipe 16 is introduced into the enlarged portion 16c where the flow cross-sectional area expands in a flared shape, so that the exhaust gas stays and rectifies without stagnation. It flows toward the member 18. The turbulent flow generated by enlarging at the enlarging portion 16 c passes through the rectifying member 18, is rectified in layers, and flows uniformly in the purifying means 17. The harmful substances contained in the exhaust gas are purified by flowing through the purification means 17, and the exhaust gas flowing out from the purification means 17 is exhausted into the first space A, where it is expanded and silenced. Next, the exhaust gas in the first space A flows from the open ends of the short pipe 20 that is the first communication pipe and the long pipe 21 that is the second communication pipe, and the exhaust gas in the short pipe 20 After being evacuated and expanded from the hole 20a to the second space B, it is sucked into the long tube 21 from the hole 21a by the suction negative pressure generated inside the long tube 21. The exhaust gas sucked into the long pipe 21 flows to the left while joining the exhaust gas flowing through the long pipe 21, and is exhausted and expanded from the hole 21b to the third space C. The exhaust gas in the third space C flows into the exhaust outlet pipe 22 from the opening end 22a and is discharged into the atmosphere.

  As described above, according to the present embodiment, the unit body in which the purifying means 17 is accommodated and integrated in the exhaust inlet pipe 16 is provided in a form in which the purifying means 17 is placed in the exhaust muffler body 10. Unlike the configuration in which the exhaust gas flowing in the exhaust inlet pipe 16 is once discharged into the space forming the expansion chamber in the exhaust muffler main body before flowing into the purification means, the total flow rate is Since it is configured to flow into the purifying means 17 as it is, it can flow to the purifying means 17 while maintaining a high exhaust gas temperature, and therefore the purifying function of the purifying means 17 is maintained without deteriorating, especially at a low speed. It is effective to improve the purification efficiency in the area, and the exhaust gas expands and contracts each time the exhaust gas flows (exhausts) into the first to third spaces A, B, C, and the sound is silenced. Been Becomes Kukoto, it will be able to be also favorably maintained mute function.

  Further, tuning is performed by appropriately adjusting the shape, size, pitch, and the like of the numerous holes 20a, 21a provided on the peripheral side surfaces of the short pipe 20 that is the first communication pipe and the long pipe 21 that is the second communication pipe. Thus, there is an effect that the exhaust noise level can be lowered by reducing the frequency of the exhaust sound by utilizing the interference of the exhaust noise.

  Further, when the exhaust gas flows from the inlet pipe portion 16a of the exhaust inlet pipe 16 toward the rectifying member 18, the exhaust gas flows through the enlarged portion 16c, so that the rectifying member 18 is smoothly smoothed so as not to cause stagnation or turbulence as much as possible. However, since the turbulent flow that still occurs is rectified by the rectifying member 18, the exhaust gas flows evenly to the purification means 17, which has the effect of improving the exhaust gas purification efficiency. is there.

  In addition, the pipe end of the exhaust outlet pipe 22 is formed with an obliquely cut end, that is, an opening end 22a, so that the exhaust gas in the third space can be easily taken in and flowed in from there. Exhaust flow noise can be reduced smoothly, and an exhaust muffler with excellent low noise performance can be realized.

  Further, since the exhaust outlet pipe 22 is attached to the left end plate member 12 provided with the exhaust inlet pipe 16, the flow of the exhaust gas flowing in the exhaust muffler main body 10 is turned in the direction of the exhaust inlet pipe 16. The exhaust muffler main body can be shortened and formed into a compact size as a whole, which makes it easy to install without having to modify the vehicle body to secure the installation space on the vehicle body side. And has the effect of being convenient.

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 purifying means 17, but it can be applied to a particulate filter of an exhaust system of a diesel engine instead. 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.

  For example, as shown in FIG. 6, the both ends of the first communication pipe 20 and the second communication pipe 21 are opened, and the communication holes 32 are provided in the second space of the second communication pipe 21 so as to communicate with each other. It is good.

  In the embodiment, the purifying means 17 is supported between the first partition wall 14 and the second partition wall 15. However, the purifying unit 17 is even placed at a position in the exhaust muffler body 10. Any position can be used.

  Further, the exhaust inlet pipe 16 is provided with the enlarged portion 16c, but without the enlarged portion 16c, the inlet pipe portion 16a may be formed so that the flow cross-sectional area thereof is substantially the same as that of the purification means 17. Good.

  Further, although only one purifying means 17 is provided, the number can be any number. In that case, the inlet pipe portion 16a may be communicated with each purifying means via a branched passage.

  In the above embodiment, the case where the space in the exhaust muffler main body 10 is formed in three spaces including the first, second, and third spaces A, B, and C has been described. Needless to say, it is possible to divide the space into two spaces, and it is also possible to form one space as an expansion chamber as a whole without providing a partition.

1 is a central longitudinal sectional view of an exhaust muffler according to a first embodiment of the present invention. FIG. 2 is a transverse cross-sectional view taken along line 2-2 in FIG. 1. FIG. 3 is a transverse cross-sectional view taken along line 3-3 in FIG. 1. (A) is a cross-sectional view taken along line 15-15 in FIG. 1, and (b) is a vertical cross-sectional view of an enlarged portion of the exhaust inlet pipe. It is a longitudinal cross-sectional view in a conventional apparatus. It is a center longitudinal cross-sectional view of the exhaust muffler which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Exhaust muffler main body 11 Outer shell 12 Left end plate member 13 Right end plate member 14 1st partition 15 Second partition 16 Exhaust inlet pipe 16a Inlet pipe part 16b Storage pipe part 16c Enlarged part 17 Purifying means 18 Rectifying member 18a Hole 20 First 1 communication pipe (short pipe)
20a hole 21 2nd communication pipe (long pipe)
21a, 21b Hole 22 Exhaust outlet pipe 22a Open end A 1st space B 2nd space C 3rd space

Claims (4)

  An engine exhaust muffler main body formed by a cylindrical outer shell and a pair of end plate members that close both ends of the outer shell, and provided with an exhaust inlet pipe for receiving the exhaust of the engine in the end plate, Purifying means is housed in the exhaust inlet pipe so that the purifying means is located inside the exhaust muffler body, and all exhaust gas flowing into the exhaust inlet pipe is circulated to the purifying means without excess or deficiency. On the other hand, an expansion chamber in which exhaust gas diffuses and expands is formed at a position facing the downstream side of the purification means, and the exhaust gas after passing through the purification means is expanded in the expansion chamber and then the end of the exhaust muffler body. An exhaust muffler configured to be discharged from an exhaust outlet pipe provided on a plate.   First, the expansion chamber formed in the exhaust muffler main body is diffused and expanded in order from the upstream side of the exhaust gas by the partition that blocks the flow of the exhaust gas inside the exhaust muffler main body from the upstream side of the exhaust. Forming a space, a second space, and a third space communicating with the exhaust outlet pipe, and allowing the first space and the second space to communicate with each other via a first communication pipe, The exhaust muffler according to claim 1, wherein the second space and the third space are communicated with each other via a second communication pipe.   In the first communication pipe and the second communication pipe, their upstream ends are opened to the first space and their downstream ends are closed, while the first communication pipe and the second communication pipe The exhaust muffler according to claim 2, wherein a hole through which exhaust gas flows is provided on a peripheral side surface. The exhaust cross-sectional area of the exhaust inlet pipe is formed so as to expand toward the purification means, and a rectifying member is provided in the exhaust inlet pipe close to the inlet end of the purification means. The exhaust muffler according to any one of claims 1 to 3, wherein the exhaust muffler is characterized by the following.

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