KR100670720B1 - Exhaust gas purifier - Google Patents

Abstract

When storing the catalyst cylindrical body consisting of a cylindrical body in the muffler to form an exhaust purification apparatus, the exhaust gas can be adjusted not only in terms of tube length, but also to improve the exhaust effect performance. It is intended to provide a purification device.

In the exhaust gas purifying apparatus formed by accommodating the catalyst cylindrical body formed from the porous plate which supported the catalyst in the muffler which has a some expansion chamber, the catalyst cylindrical body 15 is the connection pipe 11 with the exhaust pipe by the engine side. As the expansion chamber 8 closest to, it is disposed in the expansion chamber 8 upstream of the exhaust stream, and covers the outer circumference of the catalyst cylindrical body with the outer cylinder 12, and the outer cylinder is spaced in the front-rear direction to front and rear the catalyst cylindrical body. The leakage hole 17 which overlaps in the direction is provided, and it is related with the exhaust gas purification apparatus which leaked a part of exhaust gas which passes around a catalyst cylindrical body through a leakage hole to an expansion chamber.

Description

Exhaust gas purification device {EXHAUST GAS PURIFIER}

1 is a side view showing an example of a motorcycle to which the present invention is applied;

2 is a longitudinal side view of a muffler containing the exhaust gas purifying apparatus according to the first embodiment of the present invention;

3 is a cross-sectional plan view of a muffler housing the exhaust gas purifying apparatus according to the second embodiment of the present invention;

4 is a longitudinal side view of the muffler containing the exhaust gas purifying apparatus according to FIG. 3;

5 is a cross-sectional view taken along line 5-5 of FIG. 4;

6 is a cross-sectional view taken along line 6-6 of FIG. 4;

7 is a graph showing the characteristics of a muffler incorporating an exhaust gas purifying apparatus according to the present invention.

<Explanation of symbols for the main parts of the drawings>

1: muffler

8, 9, 10: expansion chamber

11: exhaust pipe

12: outer cylinder

15: cylindrical body

16: wall

17: leakage hole

The present invention relates to an exhaust gas purifying apparatus attached to a muffler.

DESCRIPTION OF RELATED ART The exhaust gas purification apparatus which accommodated the cylindrical body which consists of a punching metal etc. which carried the catalyst in the muffler is known conventionally (for example, refer Unexamined-Japanese-Patent No. 2004-150310).

The technique of the publication is that, as shown in Fig. 1 of this publication, the exhaust system E of the internal combustion engine (using the code of this publication, which is the same below) is the first exhaust pipe 1 and the second exhaust pipe 2. ) And an exhaust purification device 3 having a catalyst unit 30 disposed in the exhaust muffler 41, and the exhaust purification device 3 provides an outlet path 36 through which exhaust gas after purification flows out. It has an outlet part 34 which forms. The outlet part 34 has a taper pipe 39 constituting the convergent part, and the upstream side 39c of the taper pipe 39 has a leak hole 7 through which a part of the exhaust gas flowing through the outlet part 34 flows out. This is installed.

According to the above-mentioned conventional technique, the leakage hole provided in the conversion part is installed in the middle of the middle part of the muffler which is close to the upstream and downstream of the connection pipe with the exhaust pipe, and the leakage hole is provided at a position not overlapping with the catalyst body. It is.

By the way, when the target output of the engine is to be obtained, the output characteristic is adjusted to this leakage hole. However, in the prior art, since the position of the leakage hole is limited, fine adjustment cannot be made. Therefore, the output characteristic is an exhaust pipe. There is a limit in the degree of freedom of design because many of them depend on the length.

In addition, as shown in FIG. 1 of the prior art, when the catalyst body is disposed at the center of the muffler, it is difficult to be the best in terms of purification performance, and further, the downstream side of the muffler having a plurality of seals as shown in FIG. 4. If the leakage hole is opened in the chamber, a separate noise countermeasure is required.

This invention is made | formed in order to improve the exhaust purification apparatus installed and accommodated in the above conventional muffler.

In the present invention, when the catalyst cylindrical body made of a cylindrical body is housed and installed in the muffler to form an exhaust purification apparatus, the output of the engine can be adjusted independently of the tube length, and the exhaust effect performance can be improved. The present invention provides an exhaust gas purification device.

The invention according to claim 1 is an exhaust gas purifying apparatus formed by storing a catalyst cylindrical body formed of a porous plate carrying a catalyst in a muffler having a plurality of expansion chambers, wherein the catalyst cylindrical body is connected to an exhaust pipe on the engine side. An expansion chamber closest to the connecting pipe, disposed in the expansion chamber upstream of the exhaust stream, covering the outer circumference of the catalyst cylinder with an outer cylinder, spaced in the front and rear direction to the outer cylinder, and overlapping the catalyst cylinder with a front and rear direction; A hole is provided, and a part of the exhaust gas passing around the catalyst cylindrical body through the leaking hole is leaked to the expansion chamber.

The invention according to claim 2 is characterized in that the plurality of leak holes provided in the outer cylinder according to claim 1 are provided in the first half and the second half of the tubular body, respectively.

The invention according to claim 3 has a wall in the gap between the catalyst cylindrical body and the outer cylinder according to claim 2, and the plurality of leak holes are provided before and after the wall, respectively.

According to a fourth aspect of the invention, in the third aspect, the wall is provided in the center of the catalyst cylindrical body, and the plurality of leak holes are arranged equidistant from the front and rear of the wall.

Embodiments of the present invention will be described below based on the accompanying drawings. On the other hand, "before", "after", "left", "right", "up", "down" are Fr for the front, Rr for the rear, L for the left, and R for the right, depending on the direction viewed from the driver. . In addition, a figure shall be considered in the direction of a code | symbol.

1 is a left side view of an example of a motorcycle to which the present invention is applied.

The outline of the motorcycle is explained with this figure.

The motorcycle 210 includes a body frame 211, a front fork 212 attached to the head pipe 211a of the body frame 211, a front wheel 213 attached to the front fork 212, and a front fork. A handle 214 connected to the 212, a power unit 215 attached to the rear of the body frame 211 so as to swing up and down, a rear wheel 216 attached to the power unit 215, and a power unit. The rear cushion unit 217 which suspended the rear end part of 215, the storage box 218 attached to the upper part of the rear part of the vehicle body frame 211, and the seat | seat which were arrange | positioned on the storage box 218 so that opening and closing were possible It is a scooter type motorcycle with 219 as main components.

The power unit 215 consists of a water-cooled engine 221 in the front part and a power transmission mechanism 222 in the rear part. The engine 221 is disposed approximately horizontally with the cylinder head facing forward.

In addition, the motorcycle 210 covers the body frame 211 with the body cover 230. The body cover 230 includes a front cover 231 covering the front part of the head pipe 211a, a leg shield 232 covering the front of the driver's leg, and a step floor on which the driver's foot is placed. 233, left and right floor side covers 234 extending downward from the outer edge of the step floor 233, an under cover 235 covering between the lower edges of these floor side covers 234, and the storage box From the seat lower cover 236 which covers around the front half of 218, the rear cover 237 which covers around the rear half of the storage box 218, and the vehicle body rear part, and from these seat lower covers 236 and the rear cover 237 The side cover 238 extends downward.

The motorcycle 210 described above arranges an ignition key cylinder 241 in a portion of the leg shield 232, and arranges a fuel tank 242 and a fuel pump 243 under the step floor 233, and the body frame. The seat 219 is disposed on the upper portion of the rear frame 290 among the 211, and the reservoir tank 244 and the electrical equipment [battery (back) of the rear of the seat 219 and the rear of the rear frame 290. 245 and the control unit 246]. The reservoir tank 244 is a tank for storing the coolant of the radiator 265 for engine cooling.

In the drawing, 251 is a handle grip, 252 is a brake lever, 253 is a meter, 254 is a mirror, 255 is a winker, 256F is a handle front cover, 256R is a handle rear cover, 257 is a headlamp, 258 is a horn, 259 is a front panda, 261 is a power unit hanger, 262 is an engine starting kick pedal, 263 is an air cleaner, 264 is a carburettor, 265 is an engine cooling radiator, 266 is an engine exhaust pipe, 271 is a main stand, 272 is a rear panda and 273 is a Tail lamp, 274 is a winker, 275 is a carrier, and He is a helmet.

The muffler 1 is arranged in the front-rear direction on the right side of the wheel and is connected to the engine exhaust pipe 266.

Figure 2 is a longitudinal side view of the muffler housing the exhaust device according to the present invention.

1 shows a muffler, and the left side of the figure is the front side (engine side).

The main body of the muffler 1 is composed of a cylindrical cylindrical shell 2, and the cylindrical shell 2 is a sound absorbing material 3 between the outer cylinder 2a and the inner cylinder 2b formed of a punching metal or the like. Is filled and interposed, and the front and rear ends of the cylindrical shell 2 are closed by the front end plate 4 and the rear end plate 5.

The inside of the cylindrical outer cover body 2 in which the front and rear ends are closed by the front end plate 4 and the rear end plate 5 is partitioned by the plates 6 and 7 provided before and after the inner side cylinder 2b, and the first expansion. The chamber 8 is divided into a second expansion chamber 9 and a third expansion chamber 10.

As shown in FIGS. 1 and 2, the front end plate 4 is biased to one side and has a funnel shape biased to the lower side. The connecting pipe 11 with the exhaust pipe on the engine side is joined to the opening 4a of the funnel, and the first half 11a of the connecting pipe 11 protrudes in front of the front end plate 4, and the second half 11b It faces in the front part of the 1st expansion chamber 8 of the back surface side of the front plate 4.

The 1st diaphragm 6 which divides the 1st expansion chamber 8 and the 2nd expansion chamber 9 is provided through the rear part 12b of the outer cylinder 12 which is larger than the connection pipe 11, and is provided. . Most of the outer cylinder 12 is provided facing the first expansion chamber 8.

Between the distal end portion 12a of the outer cylinder 12 and the rear end portion 11c of the connection pipe 11, the distal end portion is joined to a funnel-shaped connection cylinder 13 which has a small diameter and is expanded in a trumpet shape over the rear portion, The rear part 12b which faces the 2nd expansion chamber 9 joins the said connection cylinder 13 and the diameter expansion front-end | tip part 14a of the symmetrical funnel-shaped connection cylinder 14.

The inside of the outer cylinder 12 is housed and provided with a concentrically smaller catalyst cylindrical body 15 (hereinafter referred to as cylindrical body).

The cylindrical body 15 is formed by winding a punching metal (porous plate) carrying a catalyst in a cylindrical shape, and is provided between the edges of the front and rear connecting cylinders 13 and 14.

The cylindrical body 15 is surrounded by the short cylindrical member 16 which closed the front-back center part in the front-back direction, and the cylindrical member 16 is joined and supported by the welding part 16a in the inner peripheral part of the outer cylinder 12, and is supported. The outer circumference of the tubular member 16 and the tubular member 15 is joined and supported by several welded portions 16a at equal intervals in a plurality of circumferential directions, and the gap is filled with a stainless wool 16b. Intervene.

Since the width of the weld can be reduced by holding the stainless wool 16b before and after the weld, the support can be maintained even when the tubular body 15 is thermally expanded. The gap between the outer cylinder 12 and the cylindrical body 15 is separated back and forth by the stainless wool 16b.

Therefore, the cylinder member 16 acts as a wall which divides the clearance gap between the outer cylinder 12 and the cylindrical body 15 back and forth.

The cylindrical body 15 provided in the said outer cylinder 12 consists of the porous board which carried the catalyst, and communicates with the upstream exhaust connection pipe 11, and exhaust exhausts the outer cylinder 12 inside and outside the cylindrical body 15. In the process, exhaust gas flows downstream, and exhaust gas passes through the cylindrical body 15 and the exhaust gas is purified to constitute an exhaust purification apparatus.

The exhaust leakage holes 17 and 17 are formed in a part of the outer cylinder 12 mentioned above. In the embodiment, two leak holes 17 and 17 are provided at the lower side and communicate with the first expansion chamber 8 outside the outer cylinder 12.

The number of the leaking holes 17 is arbitrary, and the diameter is also arbitrary, and the arrangement position of the leaking holes 17 and 17 is provided before and behind the wall 16, and the wall 16 is before and after the cylindrical body 15. It is provided in the center part, and the leak hole is equidistant from the front and back of the wall.

In this embodiment, the leakage hole is positioned at a quarter of the outer cylinder length before and after the wall due to the good results of the ease of processing and the experimental output characteristics.

The above-described catalyst cylindrical body 15, the outer cylinder 12, and the leakage holes 17 provided therein are the closest to the exhaust connection pipe 11 connected to the exhaust pipe of the engine, and a plurality of (three in the embodiment) expansion chambers. Is provided so as to open in the first expansion chamber 8 (upward expansion chamber of the exhaust stream).

The small-diameter rear portion 14b of the connecting cylinder 14 connected to the rear portion 12b of the outer cylinder 12 facing the second expansion chamber 9 is substantially U-shaped in plan view and approximately in the side view. It is connected to the front-end | tip part 18a (upstream end) of the U-shaped long 1st communication pipe 18, and the communication pipe 18 has the upstream straight line part 18b extended inside the 2nd expansion chamber 9 to the back. It exits and faces the 3rd expansion chamber 10 through the 2nd diaphragm 7.

The U-shaped portion 18c of the first communication tube 18 faces the U-turn forward in the third expansion chamber 10, and the middle-class straight portion 18d continuous to the downstream portion of the U-shaped portion 18c is the second. It penetrates the diaphragm 7 and faces in the 2nd expansion chamber 9.

The downstream straight portion 18e of the first communication tube 18 passes through the first diaphragm 6 and the opening end 18f opens in the first half of the first expansion chamber 8.

In the first expansion chamber 8, a partition tube 11 and a cylindrical body 15 carrying a catalyst are incorporated, and the outer cylinder 12 communicating with the expansion chamber 8 and the leakage holes 17 and 17 is provided. ) Is provided, and the downstream end of the communication tube 18 communicating with the exhaust gas purification device opens in the expansion chamber 8.

The 1st expansion chamber 8 and the 2nd expansion chamber 9 are connected and connected by the short 2nd communication tube 19 installed so that the 1st diaphragm 6 may penetrate, and the 2nd expansion chamber 9 and 3rd The expansion chamber 10 communicates and is connected to the short 3rd communication tube 20 provided so that the 2nd diaphragm 7 may penetrate.

The rear end plate 5 which occludes the third expansion chamber 10 from the outside is curved and swelled to the rear, and the attachment end 5a is provided in the lower part and joined to the tail pipe 21 to penetrate it. The third expansion chamber 10 communicates with the outside air.

The rear part 21b of the tail pipe 21 protrudes rearward, and the middle part-the front part 21a face in the 3rd expansion chamber 10. As shown in FIG.

In the above, the exhaust gas of the engine passes from the connecting pipe 11 into the cylindrical body 15 and flows to the communicating pipe 18 as shown by the arrow.

Moreover, since the cylindrical body 15 is formed by the porous plate and has many holes, while exhaust gas passes through the cylindrical body 15, a part of it is like an arrow in the clearance gap S between the outer cylinder 12, and the like. Leaks. Since the gap S is partitioned by the wall 16, the gap S leaks from the leak hole 17 into the first expansion chamber 8.

A part of exhaust gas leaks from the hole of the perforated plate to the gap S1 downstream of the wall 16, and the first expansion chamber (like an arrow) from the gap S1 through the leak hole 17 downstream of the wall 16. 8) Leak inside.

In this process, the exhaust gas is ignited and combusted in contact with the inner and outer circumferences of the cylindrical body 15, and the cylindrical body 15 carrying the catalyst is disposed at the most upstream portion in the muffler 1, and the ignition combustion of the exhaust gas is performed. Is made efficiently and the purification performance of the exhaust gas is improved.

In particular, since the catalyst is the expansion chamber 8 closest to the connection pipe 11 with the exhaust pipe and is arranged in the expansion chamber 8 upstream of the exhaust stream, the catalyst is disposed at a position where the catalyst is easy to react. The purification performance can be further improved.

In addition, the arrangement of the catalyst cylindrical bodies 15 improves the degree of freedom in the arrangement position of the catalyst in the muffler 1, and the output of the engine can also be adjusted by setting the number of the leak holes 17. Easy to adjust

And since the catalyst cylindrical body 15 was formed with the porous board, since exhaust gas passes through a porous hole, the airflow of exhaust gas will increase and the purification performance of exhaust gas will improve. In addition, since the leakage hole is provided upstream, no separate noise countermeasure is required.

3 is a cross-sectional plan view of a muffler of another embodiment accommodating an exhaust gas purifying apparatus according to the present invention, FIG. 4 is a longitudinal side view of the muffler, FIG. 5 is a sectional view taken along line 5-5 of FIG. 4, and FIG. 6 is 6 of FIG. 4. It is a -6 line cross section. It demonstrates, referring these drawings.

The main body of the muffler 101 is composed of a cylindrical cylindrical shell 102 as described above, the cylindrical shell 102 is between the outer cylinder 102a and the inner cylinder 102b formed of a punching metal or the like. The sound absorbing material 103 is filled and interposed, and the front and rear ends of the cylindrical outer shell body 102 are closed by the front end plate 104 and the rear end plate 105.

The inner and outer ends of the front and rear ends of the cylindrical body 102 closed by the front plate 104 and the rear end plate 105 are partitioned by diaphragms 106 and 107 provided before and after the inner cylinder 102b, and the first expansion chamber ( 108, a second expansion chamber 109, and a third expansion chamber 110.

The shear plate 104 forms a funnel that is biased to one side and downward biased as shown in FIGS. 1 and 2. The connecting pipe 111 with the exhaust pipe on the engine side is joined to the opening 104a of the funnel shape, and the first half 111a of the connecting pipe 111 projects toward the front of the front end plate 104, and the second half 111b. Faces in the front portion of the first expansion chamber 108 on the rear surface side of the front end plate 104.

The 1st diaphragm 106 which divides the 1st expansion chamber 108 and the 2nd expansion chamber 109 is provided through the rear part 112b of the outer cylinder 112 which is larger than the connection pipe 111. . Most of the outer cylinder 112 is provided facing the first expansion chamber 108.

Between the distal end portion 112a of the outer cylinder 112 and the rear end portion 111c of the connection pipe 111, the distal end portion is joined to a funnel-shaped connection cylinder 113 which is small in diameter and extends in a trumpet shape over the rear portion. The rear part 112b which faces the 2nd expansion chamber 109 joins the said connection cylinder 113 and the diameter expansion front-end | tip part 114a of the symmetrical funnel-shaped connection cylinder 114. As shown in FIG.

Inside the outer cylinder 112, a cylindrical member 115 concentrically smaller than this is stored and installed.

The cylindrical member 115 is formed by winding a punching metal carrying a catalyst into a cylindrical shape, and is provided between the edges of the front and rear connecting cylinders 113 and 114.

As shown in FIG. 4, this cylindrical body 115 is a pair of holders 116 and 116 of the substantially channel shape arrange | positioned symmetrically on the inner periphery of the axial center part of the outer cylinder 112, and the center part 116a of the outer periphery. ) Was bonded and the cylindrical body 115 was supported in the outer cylinder 112.

The cylindrical body 115 provided in the said outer cylinder 112 consists of the porous plate which carried the catalyst, and communicates with the upstream exhaust connection pipe 111, and exhaust exhausts the outer cylinder 112 in and outside of the cylindrical body 115. ) And flows downstream, and in this process, the exhaust gas is purified by passing through the cylindrical body 115 to constitute an exhaust purification apparatus.

The exhaust leakage holes 117 and 117 are formed in a part of the outer cylinder 112 mentioned above. As shown in FIG. 2, the two leakage holes 117 and 117 are provided at the lower side, and the space S between the cylindrical member 115, which is an inner cylinder member, and the outer cylinder 112, and the first outside the outer cylinder 112 are provided. The expansion chamber 108 is in communication.

The number of the leaking holes 117 is arbitrary, and the diameter is also arbitrary, and the arrangement position of the leaking holes 117 and 117 is provided in the 1/4 position in the both ends of the outer cylinder 12, respectively. Therefore, it is provided in the position spaced 1/4 each back and forth from the axial center part of the cylindrical body 15 of an inner periphery.

The small diameter rear portion 114b of the connecting tube 114 connected to the rear portion 112b of the outer cylinder 112 facing the second expansion chamber 109 is substantially U-shaped in plan view and approximately in the side view. The front end 118a (upstream end) of the first U-shaped long communicating tube 118 is connected, and the communicating tube 118 has an upstream straight portion 118b extending rearward in the second expansion chamber 109. It exits and faces the third expansion chamber 110 through the second diaphragm 107.

The U-shaped portion 118c of the first communication tube 118 faces a U-turn forward in the third expansion chamber 110, and the middle-stream straight portion 118d continuous to the downstream portion of the U-shaped portion 118c has a second shape. It penetrates the diaphragm 107 and faces in the 2nd expansion chamber 109.

The downstream straight portion 118e of the first communication tube 118 penetrates through the first diaphragm 106 and the opening end 118f opens in the first half of the first expansion chamber 108.

In the first expansion chamber 108, a partitioned connecting tube 111 and a cylindrical body 115 carrying a catalyst are incorporated, and an outer cylinder 112 communicating with the expansion chamber 108 and the leakage holes 117 and 117. ) Is installed, and the downstream end of the communication tube 118 communicating with the exhaust gas purifying device opens in the expansion chamber 108.

The first expansion chamber 108 and the second expansion chamber 109 communicate with each other through a short second communication tube 119 provided to penetrate the first diaphragm 106, and the second expansion chamber 109 and the third expansion chamber 109 are connected to each other. The expansion chamber 110 communicates with and is connected to the short third communication tube 120 provided to penetrate the second diaphragm 107.

The rear end plate 105, which occludes the third expansion chamber 110 from the outside, has a shape that is bent and expanded to the rear, and has an attachment hole 105a formed at the bottom thereof, and is bonded to penetrate the tail pipe 121. The third expansion chamber 110 communicates with the outside air.

The rear part 121b of the tail pipe 121 protrudes to the rear side, and the middle part to the front part 121a face in the third expansion chamber 110.

As described above, the catalyst cylindrical body (cylindrical body) is the expansion chamber closest to the connection pipe with the exhaust pipe on the engine side as described above, and is disposed in the expansion chamber at the most upstream of the exhaust stream, that is, the first expansion chamber 108. do.

7 is a graph showing the characteristics of the muffler incorporating the exhaust gas purifying apparatus according to the present invention.

In the graph, the horizontal axis represents engine rotation speed and the vertical axis represents engine output.

The comparative example 1 shown by the thick broken line a shows the structure which does not provide a leakage hole in the said outer cylinder 12, and the comparative example 2 shown by the thin broken line b shows that one leak hole is shown by the solid line c. Examples show each having two leak holes.

As can be seen from this graph, at the rotational speed at which the engine output is before and after the peak, c shows an embodiment in which the engine output of one leaked hole is higher and two leaked holes compared to a having no leaked hole. In the present invention, it is understood that the output characteristics are further improved as compared with Comparative Example 1.

In addition, although the example which provided two leak holes in the outer cylinder was shown in this invention, the number of leak holes is arbitrary. In addition, although the leak hole was provided in the lower side of the outer cylinder in each said Example, what is necessary is just to provide it in the arbitrary position of a circumferential direction.

The exhaust gas purifying apparatus according to the present invention is suitable for being stored and installed in a muffler of a motorcycle.

In the invention according to claim 1, the catalyst cylindrical body is an expansion chamber closest to the connection pipe with the exhaust pipe on the engine side, and is arranged in the expansion chamber upstream of the exhaust stream, covering the outer periphery of the catalyst cylindrical body with an outer cylinder, The outer cylinder is provided with a leaking hole spaced apart in the front-back direction and overlapping in the front-back direction in the catalyst cylindrical body, and a part of the exhaust gas passing through the catalyst cylindrical body through the leaking hole is leaked to the expansion chamber. Since the degree of freedom of the arrangement position of the catalyst in the inside is improved, and the output of the engine can be adjusted by setting the number of leak holes, the output is easily adjusted.

In addition, since the catalyst cylindrical body is formed of a porous plate, the exhaust gas passes through the pores, thereby increasing the airflow of the exhaust gas and improving the purification performance of the exhaust gas. In addition, since the leakage hole is provided upstream, no separate noise countermeasure is required.

In addition, since the catalyst is the expansion chamber closest to the connection pipe to the exhaust pipe and is disposed in the expansion chamber upstream of the exhaust stream, the catalyst is disposed at a position where the catalyst is easy to react, and the purification performance can be further improved.

In the invention according to claim 2, the plurality of leaking holes provided in the outer cylinder of claim 1 are respectively provided in the first half and the second half of the tubular body, so that the output of the engine can be adjusted appropriately and efficiently.

In the invention according to claim 3, in the gap between the catalyst cylindrical body and the outer cylinder in claim 2, the plurality of leak holes are provided before and after the wall, respectively, so that the punching holes before and after the cylindrical body can be efficiently The center part of a cylindrical body can be reliably supported, using, and pulling out the effect of the front and back leak hole.

In the invention according to claim 4, the wall is provided in the center of the catalyst cylindrical body in claim 3, and the plurality of leak holes are arranged equidistant from the front and rear of the wall, so that the outer cylinder can be assembled without discriminating the front and rear during assembly. .

Claims (4)

In the exhaust gas purification apparatus which accommodates the catalyst cylindrical body formed from the porous board which carried the catalyst in the muffler provided with several expansion chambers, The catalyst cylindrical body is an expansion chamber closest to the connection pipe with the exhaust pipe on the engine side, and is arranged in the expansion chamber upstream of the exhaust stream. Covering the outer circumference of the catalyst cylindrical body with an outer cylinder, the outer cylinder is provided with a leakage hole spaced in the front and rear direction and overlapping in the front and rear direction on the catalyst cylindrical body, And a portion of the exhaust gas passing through the leakage hole around the catalyst cylindrical body to the expansion chamber. The exhaust gas purification device according to claim 1, wherein the plurality of leak holes provided in the outer cylinder are respectively provided in the first half and the second half of the tubular body. The exhaust gas purification device according to claim 2, wherein the gap between the catalyst cylindrical body and the outer cylinder has a wall, and the plurality of leak holes are provided before and after the wall, respectively. The exhaust gas purifying apparatus according to claim 3, wherein the wall is provided at the center of the catalyst cylindrical body, and the plurality of leak holes are disposed at equidistant distances from the front and rear of the wall.

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