JP3237333B2 - Silencer with exhaust gas purification device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silencer with an exhaust gas purifying device, and more particularly to an exhaust gas purifying efficiency.
The present invention relates to a silencer with an exhaust gas purifying device that can compactly arrange a catalytic converter in a small silencer.

[0002]

2. Description of the Related Art In an engine, the high temperature
When high-pressure exhaust gas is directly discharged into the atmosphere, it expands rapidly and generates noise. Therefore, a muffler is provided to reduce the temperature and pressure of the exhaust gas to reduce the noise of the exhaust gas. Further, in order to purify the exhaust gas, a catalytic converter is provided in a component such as an exhaust pipe as an exhaust gas purifying device.

[0003] As a structure of such a silencer or a catalytic converter, for example, Japanese Utility Model Laid-Open No. 55-140706,
JP-A-63-36618, JP-A-55-1351
No. 18, JP-A-62-160726, and JP-A-2-61312. 55-
No. 140706 discloses a multi-cylinder engine in which an exhaust passage is provided with a honeycomb catalyst, and a plurality of exhaust gas inlets and a corresponding plurality of exhaust gas outlets are partitioned by separating upstream and downstream of the honeycomb catalyst with a separation wall. In addition, by connecting the plurality of exhaust gas inlets to the exhaust ports of the cylinders whose ignition timings are not continuous, the downstream separation chamber of the honeycomb catalyst is largely displaced to the upstream separation wall, so that the honeycomb catalyst can be moved from one exhaust gas inlet to the other. In this configuration, a part of the exhaust gas flowing into the exhaust gas flows out to another exhaust gas outlet other than the corresponding exhaust gas outlet. JP-A-63-36618 discloses a catalyst in which a metal catalyst having a catalyst supported on a metal carrier held in a holding cylinder is press-fitted into an exhaust manifold, and a flange is formed on an outlet surface of the exhaust manifold. A guide cylinder that expands toward the upstream side of the exhaust gas flow is fixed to the end of the exhaust pipe connected via the air pipe so that the open end thereof contacts the end face of the catalyst body. 55-13
Japanese Patent No. 5118 discloses a catalytic converter that removes harmful components in exhaust gas flowing into a cavity in which both ends of a cylindrical can body are closed by end plates, and a silencer that removes noise from the exhaust gas. And a catalyst converter having an upstream end plate inserted and mounted so that the catalyst portion is located in the hollow portion, and a partition in a downstream region of the catalytic converter and a front surface of the downstream end plate. A plate is provided so that a chamber formed between the partition plate and the downstream end plate is a resonance chamber. Japanese Unexamined Utility Model Publication No. Sho 62-160726 discloses a silencer with a catalytic converter in which a catalytic converter is disposed in a shell. Alternatively, a metal honeycomb catalytic converter having a circular or elliptical cross section formed by lamination is arranged on the outer periphery of an outlet pipe having a large number of small holes, and a plug is provided on the inlet pipe side of the outlet pipe. JP-A-2-
No. 61312 discloses an exhaust system in which a pipe including a muffler having an expansion chamber formed therein is connected, and an upstream end is connected to an exhaust port of an engine. The catalyst body is provided at one end of the muffler side of at least one of the tube body and the downstream tube body, and the catalyst body faces the expansion chamber.

[0004]

By the way, many mufflers in a generator engine or a general-purpose engine are not provided with a catalytic converter.
Higher concentrations of HC, CO, NO compared to vehicle engines
x, exhaust gas having exhaust emission was released to the atmosphere.

[0005] Further, as compared with a vehicle engine, in a generator engine and a general-purpose engine provided with a small silencer, there is an inconvenience that it is difficult to install a catalytic converter in the small silencer. Was.

[0006]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention firstly forms a plurality of expansion chambers by a plurality of baffle plates in a muffler body, and forms each of these expansion chambers. Set up a baffle pipe to contact,
In the muffler body, a muffler provided with an exhaust pipe for introducing exhaust gas and a tail pipe for discharging exhaust gas to the outside, wherein first to third expansion chambers are sequentially formed in the muffler body. A second baffle plate is provided in parallel and separated, and a catalyst converter is provided at an end of the exhaust pipe inserted from the third expansion chamber toward the second expansion chamber, and the catalyst converter is provided inside the muffler body. The first to third expansion chambers are disposed in the second expansion chamber on the inner side where heat radiated to the atmosphere is small,
An upstream baffle pipe and a downstream baffle pipe made of a heat-resistant material are provided at an upstream end and a downstream end of the catalytic converter, and the upstream baffle pipe and the downstream baffle pipe are provided with an upstream baffle made of a non-heat-resistant material. The exhaust pipe and the downstream fixed baffle pipe which are side fixed baffle pipes are provided. Second
In the muffler body, a plurality of expansion chambers are formed by a plurality of baffle plates, a baffle pipe is provided to connect the expansion chambers, and an exhaust pipe for introducing exhaust gas and a tail for discharging exhaust gas to the outside are provided in the muffler body. A muffler body comprising a first muffler body and a second muffler body, wherein the muffler body is divided into first and second muffler bodies;
A first baffle plate having a recess formed between the muffler body and the second muffler body; an opening end portion of a second baffle plate having a U-shaped cross section is fixed to the first baffle plate; A first expansion chamber is formed by the first baffle plate and the second baffle plate;
A second space between the first baffle plate and the second muffler body;
An expansion chamber is formed, a third expansion chamber is formed between the first baffle plate and the first muffler body, and first and second catalytic converters having the same configuration are disposed in the second expansion chamber. The first catalytic converter is provided with a first upstream baffle pipe and a first downstream baffle pipe fixed to the first baffle plate, and the second catalytic converter is provided with the first baffle pipe.
A second upstream baffle pipe and a second downstream baffle pipe fixed to a baffle plate are provided, and the first baffle plate on the third expansion chamber side is provided at a position where the first downstream baffle pipe is engaged. A throttle-shaped recess is formed at a predetermined depth on the third expansion chamber side, and the first recess is formed in the recess.
The distal end side of the downstream baffle pipe is engaged and fixed. Third, a plurality of expansion chambers are formed in the muffler body by a plurality of baffle plates, and baffle pipes are provided to connect the respective expansion chambers. The muffler body has an exhaust pipe for introducing exhaust gas and discharges exhaust gas to the outside. A muffler body, first and second baffle plates are provided side by side so as to form first to third expansion chambers, and the third expansion chamber is connected to the first expansion chamber. A communication baffle pipe formed between the first expansion chamber and the second expansion chamber and communicating the first expansion chamber and the second expansion chamber is provided on the first and second baffle plates, and the exhaust pipe is connected to the first and second baffle plates. (1) A muffler-side mounting flange is provided on the muffler body on the expansion chamber side, and a baffle pipe flange is provided on the muffler-side mounting flange via a gasket. An upstream baffle pipe, which is the first baffle pipe through which exhaust gas enters the muffler body, is fixedly provided on the baffle pipe flange, and the upstream baffle pipe is provided within the first expansion chamber where the exhaust gas temperature is the highest. It is characterized in that a catalytic converter arranged in a concave portion formed in the plate is provided.

[0007]

According to the structure of the present invention, first, the catalytic converter can be compactly installed in a small muffler body, and the catalytic converter is kept warm in the muffler body to improve exhaust gas purification. In addition, the muffler can be improved in workability and cost can be reduced, and the catalytic converter is installed at a relatively high temperature in the muffler body. Purification performance can be improved, and the baffle pipe made of a heat-resistant material is used as a part of the baffle pipe made of a heat-resistant material while the part directly in contact with the high-heat catalytic converter is used as a baffle pipe made of a non-heat-resistant material. The material cost can be reduced, and welding to the baffle plate can be facilitated to improve the manufacturing workability. Secondly, it facilitates the positioning of the baffle pipe, allows efficient exhaust gas purification by passing all of the exhaust gas into the catalytic converter, and further reduces the engine displacement with respect to the capacity of the catalytic converter. When the size is relatively large, or when the size of the chamber formed by the muffler body restricts the size of one catalytic converter, it is possible to use catalytic converters having the same dimensions and the same configuration between engines having different displacements. Thus, the effect of mass production of the catalytic converter can be exerted on a small-volume production engine, which can be advantageous in cost. Third, in the case of a two-cycle engine whose exhaust gas temperature is lower than that of a four-cycle engine, the catalytic converter is arranged at a place where the temperature of the exhaust gas passing therethrough is relatively high inside the muffler body in order to improve the purification performance of the catalyst. In addition, since the catalytic converter is kept warm, the total purification performance of the catalyst can be enhanced by arranging the exhaust gas in the first expansion chamber having the highest exhaust gas temperature in the expansion chamber constituting the muffler. Since it is not necessary to fix the catalytic converter directly to the body by welding or the like, replacement of the catalytic converter can be facilitated.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; 1 and 2 show a first embodiment of the present invention. In the figure, 2 is an engine for a generator, 4 is a cylinder head, 6 is a cylinder head cover, 8 is a spark plug, 10 is a magnet part, 12 is a rotor, 14 is a gripping part, and 16 is a fuel tank.

An exhaust pipe 18 for guiding exhaust gas from the engine 2 is attached to the cylinder head 4. That is, the head-side mounting flange 20 is connected to one end of the exhaust pipe 18, and the head-side mounting flange 20 is fixed to the cylinder head 6 by the exhaust pipe mounting bolts 22, so that the exhaust pipe 18 is connected to the cylinder head 6. Attached to

A muffler 24 is attached to the other end of the exhaust pipe 18.

As shown in FIG. 1, the muffler 24 includes a first expansion chamber 28, a second expansion chamber 30, and a third expansion chamber 32 in a space inside a box-shaped muffler body 26 from the right side of FIG. To form the first and second baffle plates 3 sequentially.
4, 36 are provided separately in parallel.

The muffler body 26 has a third expansion chamber side pipe insertion hole 3 through which the other end of the exhaust pipe 18 is inserted.
8 and a first expansion chamber side pipe insertion hole 42 through which a tail pipe 40 for guiding exhaust gas to the outside is inserted.

First and second plate pipe insertion holes 44 and 46 are formed in the first and second baffle plates 34 and 36, respectively.

The exhaust pipe 18 is inserted into the third expansion chamber side pipe insertion hole 38 and the second plate pipe insertion hole 46.
Is inserted through the other end. A metallic honeycomb type catalytic converter 48 is provided at the end of the exhaust pipe 18 on the distal end side.

The catalytic converter 48 has a metal carrier 50 made of a heat-resistant material and a holding body 52 made of a heat-resistant material for holding the carrier 50.
The second expansion chamber 30 is located between the first and second expansion chambers 32 and has less heat radiated to the atmosphere.

One end of an upstream baffle pipe 54 is fixed to one end of the upstream side of the holder 52 by welding or the like. The other end of the upstream baffle pipe 54 is fixed to the other end of the exhaust pipe 18 by welding or the like.

Further, one end of a downstream baffle pipe 56 is fixed to the other end of the holding body 52 by welding or the like.

One end of an exhaust gas introduction baffle pipe 58 is fixed to the other end of the downstream baffle pipe 56 by welding or the like. The exhaust gas introduction baffle pipe 58 is held in the first plate pipe insertion hole 44 of the first baffle plate 34, and the other end is opened to the first expansion chamber 28.

A first communication hole 60 is formed in the first baffle plate 34. The first communication hole 60 is provided with a first communication port that connects the first expansion chamber 28 and the second expansion chamber 30.
The communication baffle pipe 62 is held.

Further, a second communication hole 64 is formed in the second baffle plate 36. The second communication hole 64 is provided with a second communication port that connects the second expansion chamber 30 and the third expansion chamber 32.
The communication baffle pipe 66 is held.

The first and second baffle plates 34 and 36 have first and second tail pipe insertion holes 68 and 70 corresponding to the first expansion chamber side pipe insertion holes 42, respectively. The tail pipe 40 is provided with the first tail pipe insertion hole 68 and the second tail pipe.
Tail pipe insertion hole 70 and first expansion chamber side pipe insertion hole 4
2 to guide the exhaust of the third expansion chamber 32 to the outside.

In the first embodiment, the upstream baffle pipe 54 which is in direct contact with the catalytic converter 48 is provided.
And the downstream baffle pipe 56 is made of a heat-resistant material, and the exhaust pipe 18 and the exhaust gas introduction baffle pipe 5, which are upstream and downstream fixed baffle pipes fixed to the first and second baffle plates 34 and 36, respectively.
8 is made of a non-heat-resistant material.

Next, the operation of the first embodiment will be described.

Exhaust gas from the engine 2 is purified by the catalytic converter 48 through the exhaust pipe 18, and the exhaust gas is first introduced to reduce the pressure in the first expansion chamber 28 at the farthest point. The pressure is further reduced in the second expansion chamber 80 via the communication baffle pipe 62, attenuated in the third expansion chamber 32 via the second communication baffle pipe 66, and exhausted through the tail pipe 40 to be silenced to the outside. Is done. Thereby, while purifying the exhaust gas, the generation of the exhaust gas noise can be efficiently reduced.

By the way, the carrier 50 and the holder 52 are usually made of a heat-resistant material because the catalyst causes an oxidation or reduction reaction to generate high heat. Further, the exhaust pipe 18 connected to the holding body 52 holding the high-heat carrier 50, the upstream and downstream baffle pipes 54,
56, the exhaust gas introduction baffle pipe 58 needs to use a material excellent in heat resistance, but is disadvantageous in cost.

However, in the first embodiment, expensive heat-resistant materials are used only at locations where heat resistance is required, that is, only upstream and downstream baffle pipes 54 and 56 are used. That is, the exhaust pipe 18 and the exhaust gas introduction baffle pipe 58 are made of an inexpensive non-heat-resistant material. This can be advantageous in cost. In addition, since the exhaust pipe 18 and the exhaust gas introduction baffle pipe 58 are made of a non-heat resistant material having excellent weldability, the weldability with the first and second baffle plates 34 and 36 using a thin plate material is improved. And the manufacturing workability of the silencer 24 including the catalytic converter 48 can be improved.

Further, since the catalytic converter 48 of a metal honeycomb type is provided in the second expansion chamber 30 on the inner side, the catalytic converter 48 can be compactly installed in the relatively small muffler 24.

Further, the catalytic converter 48 is located at a position where the exhaust gas to be purified is at or above the catalytic reaction temperature, and
Since the outside atmospheric temperature of the catalytic converter 48 that absorbs the heat radiated by the catalytic converter 48 is disposed in the second expansion chamber 30 in the muffler body 26 higher than the atmospheric temperature, the catalytic converter 48 is kept warm, The purification efficiency of the catalyst can be increased. That is, in a two-cycle engine whose exhaust gas temperature is lower than that of a four-cycle engine, in order to improve the purification performance of the catalyst, the exhaust gas temperature passing through the catalytic converter 48 is disposed at a relatively high position inside the muffler 24. Since the catalytic converter 48 is kept warm, the total purification performance of the catalyst can be enhanced by disposing the catalytic converter 48 in the second expansion chamber 30 having a small surface area for transferring heat to the atmosphere in the chamber constituting the silencer 24. It is needless to say that the total purification efficiency of the catalyst can be increased also in the four-cycle engine.

Further, since the first expansion chamber 28 is disposed at a position farthest from the point where the exhaust gas is introduced, the catalytic converter 48 is connected to the baffle pipe having the highest exhaust gas temperature.
In other words, the upstream and downstream baffle pipes 54 and 56 can be set long, and the installation of the catalytic converter 48 is facilitated.

Further, since the catalytic converter 48 is mounted in the second expansion chamber 30 having the second highest ambient temperature for absorbing the radiant heat from the catalytic converter 48 after the first expansion chamber 28, the purification efficiency of the catalyst is reduced. Can be avoided.

FIGS. 3 to 6 show a second embodiment of the present invention. 3 to 6, reference numeral 102 denotes an exhaust pipe, and 104 denotes a muffler. The muffler body 106 of the silencer 104 includes the divided first and second muffler bodies 10.
6a and 106b. A first baffle plate 110 having a recess 108 is provided between the first muffler body 106a and the second muffler body 106b. This first
The opening side end portion of the second baffle plate 112 having a U-shaped cross section is fixedly provided on the baffle plate 110.

Thus, in the muffler body 106, the first expansion chamber 114 is formed by the first baffle plate 110 and the second baffle plate 112.
A second expansion chamber 116 is formed between the baffle plate 110 and the second muffler body 106b, and a third expansion chamber 118 is formed between the first baffle plate 110 and the first muffler body 106a.

As shown in FIG. 3, the first muffler body 106
a, the exhaust gas passage hole 120 and the mounting bolt insertion hole 122
Are formed.

The exhaust pipe 102 is provided with a head-side mounting flange 124 at one end and a muffler-side mounting flange 126 at the other end.

The muffler side mounting flange 126 is formed by a muffler mounting bolt 130 and a muffler mounting nut 132 which are inserted through the mounting bolt insertion hole 122 into the outer surface of the first muffler body 106a at the exhaust gas passage hole 120 via the gasket 128. Mounted.

The central portion of the second baffle plate 112 includes a muffler mounting bolt 130 and a muffler mounting nut 1.
32 is attached to the inner surface of the first muffler body 106a.

In the second expansion chamber 116, for example, as shown in FIGS.
As shown in FIG. 2, two first and second catalytic converters 134 and 136 having the same configuration are provided.

As shown in FIG. 4, the first catalytic converter 134 is provided with a first upstream baffle pipe 138 connected upstream and a first downstream baffle pipe 140 connected downstream. First upstream baffle pipe 138
Is inserted into a first upstream pipe insertion hole 142 formed on the concave portion 108 side of the first baffle plate 110 and is held by the first baffle plate 110. As shown in FIG. 6, the first baffle plate 110 on the side of the third expansion chamber 118 has a first recessed portion 144 protruding toward the third expansion chamber 118 by a predetermined depth D, as shown in FIG. 6. . The distal end side of the first downstream baffle pipe 140 is engaged with the first concave portion 144, and is fixed by welding or the like. The first downstream baffle pipe 140 has a first pipe through hole 146 formed therein.

As shown in FIG. 5, the second catalytic converter 136 has a second upstream baffle pipe 14 on the upstream side.
8 and a second downstream baffle pipe 150 is connected downstream. The distal end side of the second upstream baffle pipe 148 has the first baffle plate 11 on the first expansion chamber 114 side in the same manner as the first concave portion 144 in FIG.
0, and is fixed to the first baffle plate 110 by welding or the like. The second upstream baffle pipe 148 has a second through hole 1.
54 are formed. Second downstream baffle plate 1
The tip 50 is inserted into the second downstream pipe insertion hole 156 formed in the first baffle plate 110, opens to the third expansion chamber 118, and is fixed to the first baffle plate 110 by welding or the like.

The third expansion chamber 118 has a tail pipe 15
8 are provided.

According to the second embodiment, when the first downstream and second upstream baffle pipes 140 and 148 are fixed to the first baffle plate 110, the first and second baffle plates 110 and 148 formed on the first baffle plate 110 are fixed. The recesses 144 and 152 facilitate positioning of the first downstream and second upstream baffle pipes 140 and 148 provided with the first and second catalytic converters 134 and 136, and the first baffle plate 110 expands the second baffle plate 110. Since the chamber 116 and the third expansion chamber 118 are partitioned without any gap, the first upstream baffle pipe 18
All of the exhaust gas that has flowed into 8 can pass through the first and second catalytic converters 134 and 136, and the exhaust gas can be efficiently purified.

When the displacement of the engine 2 is relatively large with respect to the capacity of one catalytic converter,
When the size of the chamber constituting the silencer 104 regulates the size of one catalytic converter, the desired exhaust gas purification performance cannot be obtained with only one catalytic converter. Because it is arranged,
It is possible to use catalytic converters with the same dimensions and the same configuration between engines with different displacements, and to achieve the effect of mass production of catalytic converters on engines with small production volumes, preventing cost increases. it can.

FIG. 7 shows a third embodiment of the present invention. In FIG. 7, reference numeral 202 denotes an exhaust pipe,
Reference numeral 204 denotes a silencer. In the space inside the muffler body 206 of the silencer 204, the first expansion chamber 212 and the second
An expansion chamber 214 and a third expansion chamber 216 are formed. The third expansion chamber 216 includes the first expansion chamber 212 and the second expansion chamber 2.
14 are formed.

First and second baffle plates 208 and 21
0, first and second communication holes 218 and 220 are formed, and the first and second communication baffle pipes 222 are held in the first and second communication holes 218 and 220. Further, a third communication hole 224 is formed in the second baffle plate 210, and a second communication baffle pipe 226 is held in the third communication hole 224.

The exhaust pipe 202 has a head-side mounting flange 228 connected to one end thereof and a muffler-side mounting flange 230 connected to the other end thereof.

The muffler-side mounting flange 230 of the exhaust pipe 202 is mounted to the baffle pipe flange 238 by a muffler-side mounting bolt 234 and a muffler-side mounting nut 236 via a first gasket 232.
The baffle pipe flange 238 has an upstream baffle pipe 244 to which a catalytic converter 242 is attached.
Is fixed by welding or the like.

In the recess 246 of the first baffle plate 208, a protector plate 248 is attached at a position where the catalytic converter 242 is located.

Further, a tail pipe 250 is provided in the third expansion chamber 216.

That is, the catalytic converter 242 is provided in the upstream baffle pipe 244 which is the first baffle pipe into which the exhaust gas from the engine enters the muffler 204, and the catalytic converter 242 has the highest exhaust gas temperature in the expansion chamber. It is provided in the first expansion chamber 212.

According to the third embodiment, the exhaust gas temperature is 4
In a two-cycle engine lower than the cycle engine, the catalytic converter 242 is disposed at a position where the temperature of the exhaust gas passing therethrough is relatively high inside the muffler 204 in order to improve the purification performance of the catalyst. Since the temperature of the exhaust gas 242 is maintained, the exhaust gas in the expansion chamber constituting the silencer 204 can be disposed in the first expansion chamber 212 having the highest exhaust gas temperature to improve the total purification performance of the catalyst.
It is needless to say that the total purification efficiency of the catalyst can be increased also in the four-cycle engine.

The catalytic converter 242 is connected to the muffler 20
4, the catalyst converter 242 is provided together with a separate upstream baffle pipe 244 on the baffle pipe flange 238 without being fixedly fastened by welding or the like. It is only necessary to replace the upstream baffle pipe 244 having the catalytic converter 242, rather than the silencer having the baffle pipe fixedly provided, and the user bears less money, which is advantageous in cost.

The present invention is not limited to the above-described embodiment, but can be variously modified.

For example, as a first modification of the first embodiment,
As shown in FIG. 8, a first expansion chamber 310, a second expansion chamber 312, and a third expansion chamber 314 are formed in a muffler body 304 of a muffler 302 by first and second baffle plates 306 and 308, and a catalytic converter is formed. The first expansion chamber 310 and the second expansion chamber 31 are provided on the distal end side of the exhaust pipe 318 and in the second expansion chamber 312.
The first communication baffle plate 320 that communicates with the first
The first communication hole 322 of the baffle plate 306 is provided, the tail pipe 324 is provided in the second expansion chamber 312, and the exhaust pipe 318 is formed with a through hole 326 opening to the third expansion chamber 314. Thereby, the same effect as in the first embodiment can be obtained.

As a second modification of the first embodiment, as shown in FIG. 9, in a muffler body 404 of a silencer 402, a first expansion chamber 410 is formed by a first baffle plate 406 and a second baffle plate 408. And the second expansion chamber 412 and the third expansion chamber 414, and the first expansion chamber 41
0, a catalytic converter 416 is fixed to the first baffle plate 406 by one side baffle pipe 418 and is fixed to the second baffle plate 408 by the other side baffle pipe 420. And the second expansion chamber 412 are communicated by a communication baffle pipe 424 held in a communication hole 422 of the second baffle plate 408.
The tail pipe 426 is installed in the exhaust pipe 42
8 is disposed in the first expansion chamber 410. Thereby, the same effect as in the first embodiment can be obtained.

Further, as a third modification of the first embodiment, as shown in FIG. 10, the muffler body 504 of the muffler 502 is constituted by first and second muffler bodies 504a and 504b, and the first muffler body 504a is provided. A baffle plate 506 is provided between the first muffler body 504b and the first muffler body 504b, thereby forming first and second expansion chambers 508 and 510, and a catalyst converter 512 is provided in the first expansion chamber 508. An upstream baffle pipe 514 is provided at the upstream end, and a downstream baffle plate 516 is provided at the downstream end of the catalytic converter 512. Further, a part of the baffle plate 506 is bent in a semicircular shape toward the first expansion chamber 508 to form a curved portion 506a.
The tail pipe 518 is fixed to a. Curved portion 506a
A holder 520 is erected on the first expansion chamber 508 side, and an upstream baffle pipe 514 is fixed to the holder 520, and a downstream baffle pipe 516 is inserted through a pipe insertion hole 522 formed in the baffle plate 506. And stick. This has the same effect as the first embodiment.

As a modification of the third embodiment, as shown in FIG. 11, first and second baffle plates 606 and 608 are juxtaposed in a muffler body 604 of a muffler 602, and a first expansion chamber 610 and a second An expansion chamber 612 and a third expansion chamber 614 are formed, and a first communication baffle pipe 616 connecting the first expansion chamber 610 and the second expansion chamber 612 is formed in the first and second baffle plates 606 and 608. 1, second communication hole 6
18, 620 and a second communication baffle pipe 6 for communicating the second expansion chamber 612 and the third expansion chamber 614.
22 is provided in the third communication hole 624 formed in the second baffle plate 608, and a tail pipe 626 is provided in the third expansion chamber 614. Also, the exhaust pipe 6
A converter holding portion 630 is formed on the other end of the muffler body 604, and a catalytic converter 632 is accommodated in the converter holding portion 630.
The muffler mounting flange 636 of the exhaust pipe 628 is joined via a second gasket 638 on the inner surface of the muffler body 604 via a muffler mounting bolt 640 and a muffler mounting nut 642. The downstream baffle pipe 644 connected to the converter 632 is connected to the baffle pipe flange 646.
To be fixed. Thus, the same effect as in the third embodiment can be obtained.

In the above-described embodiment, the engine for the generator is used. However, the muffler 704 of the engine 702 as shown in FIGS.
It goes without saying that each embodiment of the present invention can be applied.

Further, in the first embodiment, the catalytic converter 48 is connected to the exhaust pipe 18 and the tail pipe 40.
, And also in the third expansion chamber 32.

Furthermore, in the second embodiment, two or more catalytic converters can be provided in one expansion chamber, and each catalytic converter can be separately provided not only in the same chamber but also in other chambers. It is also possible to provide. Obtainable.

[0060]

As is apparent from the above detailed description, according to the present invention, first, the first and second baffle plates are formed in the muffler body so that the first to third expansion chambers are sequentially formed. A catalyst converter is provided at an end of an exhaust pipe inserted in parallel from the third expansion chamber to the second expansion chamber side, and the catalyst converter is installed in the muffler body in the atmosphere in the first to third expansion chambers. And an upstream baffle pipe and a downstream baffle pipe made of a heat-resistant material are provided at the upstream end and the downstream end of the catalytic converter. The baffle pipe and the downstream baffle pipe are provided with an exhaust pipe and a downstream fixed baffle pipe, which are upstream fixed baffle pipes made of non-heat-resistant material. Data can be installed compactly in a small muffler body, and the catalytic converter is kept warm in the muffler body to improve exhaust gas purification, and also to improve muffler manufacturing workability and reduce costs. In addition, since the catalytic converter is installed at a relatively high temperature in the muffler body, it is possible to keep the temperature of the catalytic converter properly and improve the total purification performance of the catalyst. The baffle pipe made of heat-resistant material is used for the parts in direct contact, while the other baffle pipes are made of non-heat-resistant material, reducing material costs and facilitating welding to the baffle plate. Thus, manufacturing workability can be improved. Secondly, a muffler body is constituted by divided first and second muffler bodies, and a first baffle plate having a recess formed between the first muffler body and the second muffler body is provided. Is provided by fixing an opening end portion of a second baffle plate having a U-shaped cross section, a first expansion chamber is formed by the first baffle plate and the second baffle plate, and a first expansion chamber is formed between the first baffle plate and the second muffler body. A second expansion chamber, a third expansion chamber is formed between the first baffle plate and the first muffler body, and the first and second catalytic converters having the same configuration are disposed in the second expansion chamber. The first catalytic converter has a first upstream baffle pipe fixed to a first baffle plate and a first catalytic converter.
A downstream baffle pipe is provided, a second catalytic converter is provided with a second upstream baffle pipe and a second downstream baffle pipe fixed to the first baffle plate, and a first baffle plate on the third expansion chamber side is provided with a second baffle pipe. (1) A throttle-shaped concave portion is formed at a predetermined depth on the third expansion chamber side at a position where the downstream baffle pipe is engaged, and the distal end side of the first downstream baffle pipe is engaged with the concave portion to fix the concave portion. With this arrangement, a recess is formed in the part of the baffle plate with which the baffle pipe engages, facilitating the positioning of the baffle pipe, and efficiently purifying the exhaust gas by passing all of the exhaust gas through the catalytic converter. Further, when the engine displacement is relatively large with respect to the capacity of the catalytic converter, and when the size of the chamber formed by the muffler body is one catalytic converter, When regulating the size, catalytic converters with the same dimensions and the same configuration can be used between engines with different displacements. It can be advantageous. Third, in the muffler body, first and second baffle plates are provided side by side so as to form first to third expansion chambers, and the third expansion chamber is provided between the first expansion chamber and the second expansion chamber. A communication baffle pipe is formed on the first and second baffle plates for communicating the first expansion chamber and the second expansion chamber, and an exhaust pipe is provided on the muffler body on the first expansion chamber side with a muffler side mounting flange. A baffle pipe flange is provided on the muffler side mounting flange via a gasket, and an upstream baffle pipe, which is the first baffle pipe through which exhaust gas enters the muffler body, is fixedly provided on the baffle pipe flange. Is provided with a catalytic converter disposed in a recess formed in the first baffle plate in the first expansion chamber having the highest exhaust gas temperature. In a two-cycle engine having a lower than four-cycle engine, in order to improve the purification performance of the catalyst, the catalytic converter is disposed at a place where the temperature of the exhaust gas passing therethrough is relatively high inside the muffler body, and In the chamber that constitutes the silencer, the exhaust gas temperature can be increased by placing it in the first expansion chamber where the exhaust gas temperature is highest, and the catalytic converter can be directly welded to the muffler body, etc. Therefore, the replacement of the catalytic converter can be facilitated.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a muffler according to a first embodiment.

FIG. 2 is a configuration diagram of an engine.

FIG. 3 is a plan view of a muffler according to a second embodiment.

FIG. 4 is a configuration diagram taken along line IV-IV in FIG. 3;

FIG. 5 is a configuration diagram taken along line VV in FIG. 3;

FIG. 6 is an enlarged sectional view taken along arrow VI in FIG. 4;

FIG. 7 is a configuration diagram of a muffler according to a third embodiment.

FIG. 8 is a configuration diagram of a muffler according to a first modification of the first embodiment.

FIG. 9 is a configuration diagram of a muffler according to a second modification of the first embodiment.

FIG. 10 is a configuration diagram of a muffler according to a third modification of the first embodiment.

FIG. 11 is a configuration diagram of a muffler according to a modification of the third embodiment.

FIG. 12 is a perspective view of another engine.

FIG. 13 is a side view of another engine of FIG.

[Explanation of symbols]

 2 Engine 18 Exhaust pipe 24 Silencer 26 Muffler body 28 First expansion chamber 30 Second expansion chamber 32 Third expansion chamber 34 First baffle plate 36 Second baffle plate 40 Tail pipe 48 Catalytic converter

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F01N 3/20-3/28

Claims (3)

(57) [Claims] A plurality of expansion chambers are formed in a muffler body by a plurality of baffle plates, and a baffle pipe is provided for connecting the expansion chambers. The muffler body has an exhaust pipe for introducing exhaust gas and an exhaust pipe for exhaust gas. in muffler provided with a tail pipe for discharging said Ma
First to third expansion chambers are sequentially formed in the hula body.
First and second baffle plates are provided separately in parallel,
The third expansion chamber is inserted through the second expansion chamber.
Provide a catalytic converter at the end of the exhaust pipe
Together with this catalytic converter inside the muffler body.
And there is little radiant heat to the atmosphere in the first to third expansion chambers.
On the side of the second expansion chamber and above the catalytic converter.
An upstream cover made of a heat-resistant material is provided at the flow end and the downstream end.
A baffle pipe and a downstream baffle pipe.
Not resistant to downstream baffle pipe and downstream baffle pipe
The upstream fixed baffle pipe made of a thermal material;
A silencer with an exhaust gas purifying device, comprising an exhaust pipe and a downstream fixed baffle pipe . 2. A baffle play in a muffler body.
Form a plurality of expansion chambers, and connect these expansion chambers
A baffle pipe is provided for the muffler body.
Exhaust pipe for introducing gas and exhaust gas to the outside
Muffler with a tail pipe
Consists of first and second muffler bodies with a divided hula body
And between the first muffler body and the second muffler body
Is provided with a first baffle plate in which a concave portion is formed.
The first baffle plate has a second baffle plate having a U-shaped cross section.
The first end portion is fixedly provided at the opening side end portion of the plate.
First inflation by the first plate and the second baffle plate
A first baffle plate and a second muffler chamber;
A second expansion chamber is formed between the first baffle plate and the first baffle plate.
And a third expansion chamber is formed between the first muffler body and the first muffler body.
The first and second catalytic converters having the same configuration are arranged in the two expansion chambers.
And the first catalytic converter has the first baffle
A first upstream baffle pipe fixed to the rate and a first upstream baffle pipe;
Providing a downstream baffle pipe, wherein the second catalytic converter
A second upstream side fixed to the first baffle plate
Providing a baffle pipe and a second downstream baffle pipe;
The first baffle plate on the third expansion chamber side has the
The third expansion is provided at a position where the first downstream baffle pipe is engaged.
Form a squeeze-shaped recess at a predetermined depth on the tension chamber side, and
Is engaged with the distal end side of the first downstream baffle pipe.
A silencer with a gas purifier, which is fixed. 3. A baffle play in a muffler body.
Form a plurality of expansion chambers, and connect these expansion chambers
A baffle pipe is provided for the muffler body.
Exhaust pipe for introducing gas and exhaust gas to the outside
Muffler with a tail pipe
The first to third expansion chambers are formed in the hula body.
1. A second baffle plate is provided side by side and
A third expansion chamber between the first expansion chamber and the second expansion chamber;
Forming a communication between the first expansion chamber and the second expansion chamber.
The communication baffle pipe is connected to the first and second baffle plates.
And the exhaust pipe is connected to the first expansion chamber side.
The muffler body is provided with a muffler side mounting flange.
Baffle on muffler side mounting flange via gasket
A pipe flange is provided and this baffle pipe flange
Is the first baffle pie where exhaust gas enters the muffler body
The upstream baffle pipe, which is a
The first baffle pipe with the highest exhaust gas temperature
In the recess formed in the first baffle plate in the expansion chamber
Exhaust catalyst characterized by having a catalytic converter arranged
Silencer with gas device purification device.