JPWO2006080441A1 - Muffler for small engines - Google Patents

Abstract

Exhaust gas connected to the exhaust port of the engine, with the goal of providing a muffler for small engines that has a large silencing effect, a large exhaust gas purification effect, is easy to manufacture, and is inexpensive to manufacture. The first expansion chamber 12 is divided into the first expansion chamber 12 for exhaust gas having an inlet 11 and the first expansion chamber 12 through a partition plate 14, and through the first vent 13 of the partition plate 14. A second expansion chamber 15 of exhaust gas communicating with the second expansion chamber 15 through the partition plate 14 and the second expansion chamber 15 through the second vent 16 of the partition plate 14. A third expansion chamber 18 of exhaust gas having an exhaust gas outlet 17 in communication with the exhaust gas inlet 11. The exhaust gas inlet 11 is provided with a first heat-resistant mesh catalyst 19. Heat vent knit at vent 13 Characterized in that a first exhaust gas purifier 20 made of those coated with a catalyst for purifying exhaust gases in the earth 20a.

Description

  The present invention relates to a muffler for a small engine suitable for use in, for example, a small engine used in a brush cutter or a chain saw.

  As shown in FIG. 21, the muffler used in the conventional small engine includes a first expansion chamber 2 having an exhaust gas inlet 1 connected to an exhaust port of the engine and a second expansion having an exhaust gas outlet 3. A chamber 4 and a stainless steel base having numerous honeycomb-shaped small holes along the axial direction between the first expansion chamber 2 and the second expansion chamber 4, for example, The exhaust gas purifier 5 is provided with a catalyst coated with a catalyst for purifying exhaust gas that is a combination of two or more of platinum, rhodium, and palladium.

  Further, as shown in FIG. 22, a muffler used for a conventional small engine has a first expansion chamber 2 for exhaust gas having an exhaust gas inlet 1 connected to an exhaust port of the engine, and a second having an exhaust gas outlet 3. Of the exhaust gas receiving member 6 having a plurality of ventilation holes 6b formed in the concave surface 6a, and the first expansion chamber 2 with the concave surface 6a facing the exhaust gas inlet 1. The exhaust gas is purified by, for example, a stainless steel base having numerous honeycomb-like small holes along the axial direction between the first expansion chamber 2 and the second expansion chamber 4. The exhaust gas purifier 5 coated with the catalyst was provided. 21 and 22, reference numeral 2 a is a wall forming the first expansion chamber 2, reference numeral 4 a is a wall forming the second expansion chamber 4, and reference numeral 7 is the first expansion chamber 2. And a partition plate that partitions the second expansion chamber 4.

  Various mufflers for conventional small engines have been developed. For example, the catalyst carrier used in the muffler is formed by stacking thin metal plates having a large number of openings on both sides of the cross catalyst, the catalyst carrier is curved in a waveform, and the thin metal plate of the catalyst carrier is exhausted. It is configured to be parallel to the flow (Patent Document 1).

  The following are known as conventional exhaust mufflers. The exhaust muffler accommodates therein a plurality of coarse cylindrical cross catalysts and a narrow cylindrical cross catalyst. Each cylindrical cross catalyst is relatively soft, and is formed by joining the catalyst to a heat resistant fabric and having a cylindrical shape with an elliptical cross section. The coarse-shaped cylindrical cross catalyst is disposed at the top of the exhaust muffler so as to surround two reinforcing beams, and the exhaust port of the engine communicates with the interior of the coarse-cylindrical cross catalyst through the opening of the exhaust muffler. Is done. The coarse cylindrical cross catalyst surrounds two reinforcing beams at the lower part of the exhaust muffler, and the peripheral edge of the cylindrical cross catalyst is partially disposed in close contact with the inner wall surface of the exhaust muffler. . Therefore, the inside of the exhaust muffler includes a chamber inside the coarse cylindrical cross catalyst, a chamber outside the cylindrical cross catalyst, a chamber of the thin cylindrical cross catalyst, and the outside of the cylindrical cross catalyst. The exhaust muffler is divided into the lowermost chamber of the exhaust muffler (Patent Document 2).

  The following are known as conventional exhaust mufflers. In this exhaust muffler, a plurality of catalyst carriers are coupled in series in an exhaust passage. Each catalyst carrier is covered with a metal mesh by stacking the catalyst on a holding plate having an opening. One catalyst carrier holding plate is substantially horizontally coupled to the upper case of the exhaust muffler. The other catalyst carrier holding plate is coupled substantially horizontally to the lower case of the exhaust muffler. The exhaust muffler is divided into three chambers in the exhaust flow direction by the holding plate. This exhaust muffler is configured by the mesh of the catalyst carrier on the exhaust inlet side being coarse and the mesh of the catalyst carrier on the outlet side being narrow (Patent Document 3).

  The following is known as a conventional exhaust muffler structure. The exhaust muffler structure includes a substantially box-shaped exhaust muffler that can be divided and integrated into an inner exhaust muffler piece and an outer exhaust muffler piece, and exhaust gas from an internal combustion engine provided in the exhaust muffler. In the exhaust muffler structure of an internal combustion engine having a communication hole leading into the inside and a tubular member having appropriate elasticity and sandwiching the catalyst between the holding nets, the tubular member has a body portion thereof. The exhaust muffler is disposed in a space so as to be sandwiched between the muffler pieces. According to such an exhaust muffler structure, when the inner and outer exhaust muffler pieces are integrated, the cylindrical member can be adapted to the surrounding shape as long as it is installed in the space between the two. The body is freely elastically deformed and held (Patent Document 4).

  The following are known as conventional engine mufflers. That is, a cylindrical spark arrester is formed of a cylindrical wire mesh member, which is a means for preventing the scattering of sparks, and this cylindrical spark arrester is sandwiched between the end of the tail pipe and the inner surface of the muffler mounting body. (Patent Document 5).

  The following is known as a conventional exhaust muffler structure. A partition plate is provided in the muffler along the axial center direction of the cylinder in the engine. In the muffler, a first chamber on the side close to the engine body and a second chamber on the side away from the engine body are provided in the muffler. It is divided into rooms. The catalyst is held in the lower part of the partition plate. This catalyst has a function of recombusting unburned gas in the exhaust gas by an oxidation reaction, and is formed by coating the catalyst on the surface of the passage of a honeycomb structure made of stainless steel. An inner catalyst cover that is located in the first chamber and covers almost the inner half of the catalyst and an outer catalyst cover that is located in the second chamber and covers almost the outer half of the catalyst are attached to the partition plate. Yes. A space surrounded by the inner catalyst cover and the partition plate is a first catalyst chamber, and an inlet-side communication port that communicates the first catalyst chamber and the first chamber is formed in the inner catalyst cover. A space surrounded by the outer catalyst cover and the partition plate is a second catalyst chamber, and an outlet-side communication port that connects the second catalyst chamber and the second chamber is formed in the outer catalyst cover. And the catalyst storage case which accommodates a catalyst is formed by attaching these inner catalyst covers and outer catalyst covers to a partition plate (patent document 6).

  The following are known as mufflers of conventional internal combustion engines. The muffler includes an expansion chamber into which exhaust gas ejected from an exhaust port of the internal combustion engine is introduced, and an outer wall panel in which an outer peripheral portion of the expansion chamber is appropriately separated so as to form a gap space therebetween. The outer wall panel is formed by a double wall part, and the inner wall panel is formed with a blow-out port that guides the exhaust gas in the expansion chamber to the gap space, and the outer wall panel receives the exhaust gas from the gap space. A discharge opening for discharging to the outside is formed, and a spark arrester screen is disposed so as to cover the discharge opening. Further, a columnar oxidation catalyst made of a metal carrier is disposed as an exhaust gas purification member so as to protrude into both the first expansion chamber and the second expansion chamber (Patent Document 7).

  The following is known as a conventional catalyst muffler structure. In this catalyst muffler structure, the muffler is divided into a main case and a lid case, a ceramic woven cloth, a cloth catalyst and a stainless steel wire mesh are three-dimensionally molded into the shape of each case, and the entire inner wall of each case is ceramic A woven fabric, a cloth catalyst, and a metal mesh made of stainless steel are overlapped and joined in this order (Patent Document 8).

The following are known as conventional silencers. This silencer is a silencer for a general-purpose internal combustion engine in which the outer peripheral portion of the separator is sandwiched between the upper and lower casings, which are divided into two vertically, and the outer periphery of the separator is crimped. An inlet opening and an outlet opening for communicating the first and second chambers divided by the separator with the exhaust port and the outside air of the internal combustion engine are provided in the silencer, and the inlet opening is provided in the first chamber. A cylindrical body having small holes or voids is attached, and an exhaust gas purification catalyst is attached to the cylindrical body (Patent Document 9).
JP-A-6-248939 (see paragraphs 0012 and 0014 and FIG. 2) JP-A-6-66137 (see paragraphs 0010 and 0011 and FIG. 2) JP-A-6-33754 (see paragraph 0010 and FIG. 1) JP-A-7-293231 (see paragraphs 0010 and 0012 and FIGS. 1 and 2) Japanese Utility Model Publication No. 7-40648 (see FIGS. 3 and 4) JP 2002-242666 (see paragraphs 0034, 0035, 0036 and FIG. 1) JP-A-10-8942 (see paragraphs 0006, 0014, 0024 and FIGS. 1 and 2) Japanese Utility Model Laid-Open No. 6-18617 (see Claims for Utility Model Registration and FIGS. 1 and 2) Japanese Utility Model Laid-Open No. 5-21114 (see Claims for Utility Model Registration and FIGS. 1 and 2)

  However, in the muffler of the conventional engine shown in FIG. 21, for example, the exhaust gas purifier 5 in which a catalyst for purifying exhaust gas is coated on a honeycomb-shaped stainless steel base is complicated, and its manufacture is complicated. There was a problem that the manufacturing cost was high.

  Further, an exhaust gas receiving member 6 which is a conventional improved muffler component as shown in FIG. 22 is formed in a concave shape having a plurality of vent holes 6b formed in a concave surface 6a. There was no function to purify.

  In the exhaust treatment muffler of the two-stroke engine as described in Patent Document 1, the catalyst carrier used for the muffler is formed by overlapping thin metal plates having a large number of openings on both sides of the cross catalyst. Since the carrier is curved in a waveform and the thin metal plate of the catalyst carrier is configured to be parallel to the exhaust flow, there is a problem that the production is complicated and the production cost is increased.

  The exhaust process muffler of the two-stroke engine as described in Patent Document 2 is not provided with a heat-resistant mesh catalyst at the exhaust gas inlet, and is not provided with a heat-resistant mesh catalyst at the exhaust gas outlet. In the engine operating state, there is a problem that sparks may be ejected from the exhaust gas outlet.

  Also in the exhaust treatment muffler of the two-stroke engine as described in Patent Document 3, the exhaust gas inlet is not provided with a heat resistant mesh catalyst, and the exhaust gas outlet is not provided with a heat resistant mesh catalyst. Therefore, there has been a problem that sparks may be ejected from the exhaust gas outlet in the operating state of the engine.

  In the exhaust muffler structure of the internal combustion engine as described in Patent Document 4, the inside of the exhaust muffler is not divided into a first expansion chamber, a second expansion chamber, and a third expansion chamber via a partition plate. There was a problem that the silencing effect was not good.

  In the engine muffler described in Patent Document 5, a cylindrical spark arrester formed of a cylindrical wire mesh member is sandwiched between the tail pipe end and the inner side surface of the muffler mounting body. Since it is held in a state, it is difficult to replace it with a new one.

  In the exhaust muffler structure of a small engine as described in Patent Document 6, a catalyst having a function of recombusting unburned gas in the exhaust gas by an oxidation reaction is provided on the surface of the passage of the honeycomb structure made of stainless steel. Since it was formed by coating the catalyst, there was a problem that the production was troublesome and the production cost was high.

  In the muffler of the internal combustion engine as described in Patent Document 7, a columnar oxidation catalyst made of a metal carrier is provided with an exhaust gas purification member so as to protrude into both the first expansion chamber and the second expansion chamber. However, the cylindrical oxidation catalyst has a problem that the production cost is high. Further, between the inner wall panel and the outer wall panel forming the double wall portion, the exhaust gas flows to the discharge opening provided in the outer wall panel and the outer wall panel is heated, so this double wall portion is the outer wall of the muffler. There was a problem that there was no effect of preventing heating.

  In the catalyst muffler structure as described in Patent Document 8, the muffler is not divided into a first expansion chamber, a second expansion chamber, and a third expansion chamber via a partition plate, so that the sound deadening effect is good. Absent. Moreover, the catalyst provided inside the muffler is obtained by dividing the muffler into a main case and a lid case, and superposing and bonding a ceramic woven cloth, a cross catalyst, and a stainless steel wire mesh in order on the entire inner wall of each case. Therefore, there is a problem that the structure is complicated and the manufacturing cost increases.

  The silencer as described in Patent Document 9 has a problem in that the exhaust gas purification catalyst is insufficient because the exhaust gas purification catalyst is not provided in the separator that divides the silencer into two parts. .

  A muffler for a small engine as an embodiment of the present invention includes a first expansion chamber (12) for exhaust gas having an exhaust gas inlet (11) connected to an exhaust port of the engine, and a partition plate (14). And a second exhaust gas that communicates with the first expansion chamber (12) through the first vent (13) of the partition plate (14). And the second expansion chamber (15) through the partition plate (14), and the second expansion chamber (15) through the second vent (16) of the partition plate (14). A third expansion chamber (18) of exhaust gas having an exhaust gas outlet (17) communicating with the expansion chamber (15) of the first exhaust gas inlet (11), and a first heat-resistant mesh A catalyst (19) is provided, and the first vent (13) of the partition plate (14) Characterized in that a sexual knitted fabric first exhaust gas purifier made of those coated with a catalyst for purifying exhaust gas (20a) (20).

  Further, in the muffler, the first exhaust gas purifier (20) has at least one exhaust gas inlet (20d) formed by coating a heat-resistant knitted fabric (20a) with a catalyst for purifying exhaust gas. It can be formed by being held by a heat resistant cover (20b).

  In the muffler, the first vent (13) of the partition plate (14) is provided with the first exhaust gas purifier (20) on the exhaust gas inlet side, and on the outlet side thereof the second exhaust gas purifier (20). And a heat-resistant cover (22) having a plurality of exhaust gas outlets (22a) are provided, and the exhaust gas outlet (17) is replaceable with a third heat-resistant mesh catalyst (21). (23) may be provided.

  In the muffler, the first exhaust gas purifier (20) is a cover (20c) formed of a heat-resistant mesh made by coating a heat-resistant knitted fabric (20a) with a catalyst for purifying exhaust gas. It may be formed by holding.

  In the muffler, at least the outer wall of the second expansion chamber (15) that is not on the side attached to the engine may be formed of a double wall (15a ', 15b).

  In the muffler, at least the outer wall of the second expansion chamber (15) that is not on the side attached to the engine is formed by double walls (15a ', 15b), and a heat insulating material (15c) is provided between the double walls. It is good also as what was filled.

  In the muffler, an exhaust gas receiving member (24) is provided in the first expansion chamber (12) facing the exhaust gas inlet (11), and the exhaust gas receiving member (24) is provided in the exhaust gas inlet. (11) is connected to the exhaust gas inlet (11), and is provided with an exhaust port (24b). The exhaust gas receiving member (24) has an exhaust port (24b) in the vicinity of the exhaust port (24b) and exhausted to a heat-resistant knit fabric A second exhaust gas purifier (25) coated with a catalyst for purifying gas is accommodated, and exhaust gas flows through the exhaust port (24b) in the direction of the first exhaust gas purifier (20). The inclined surface (24a) can be formed.

  In the muffler, the first heat-resistant mesh catalyst (19) may be configured by coating a mesh made of SUS310s stainless steel and a catalyst for purifying exhaust gas.

  In the muffler, the second heat-resistant mesh catalyst (21) is formed by coating a SUS310s stainless steel mesh with a catalyst for purifying exhaust gas, and the heat-resistant cover (22) is made of SUS310s stainless steel. -It may be constituted by a steel plate, and the third heat-resistant mesh catalyst (23) may be constituted by coating a SUS310s stainless steel mesh with a catalyst for purifying exhaust gas.

  In the muffler, the exhaust gas receiving member (24) may be formed of a SUS310s stainless steel plate.

  A muffler for a small engine according to another embodiment of the present invention includes an exhaust gas first expansion chamber (12) having an exhaust gas inlet (11) connected to an exhaust port of the engine, a partition plate ( 14) through the second expansion chamber (15) partitioned from the first expansion chamber (12) and the second vent (16) of the partition plate (14). A third expansion chamber (18) having an exhaust gas outlet (17) communicating with (15), and the exhaust gas inlet (11) is provided with a first heat-resistant mesh catalyst (19), The partition plate (14) is integrally formed with a protrusion (14b) having at least one first vent (14a) and protruding toward the first expansion chamber (12). 14b) in the recess on the second expansion chamber (15) side, the heat-resistant knitted fabric (20a) and the exhaust gas The first exhaust gas purifier (20) coated with a catalyst for purifying the exhaust gas is mounted, and the exhaust gas outlet (22a) covers the first exhaust gas purifier (20) from the second expansion chamber (15) side. A heat-resistant cover (22) having the above is provided.

  A muffler for a small engine according to still another embodiment of the present invention includes an exhaust gas first expansion chamber (12) having an exhaust gas inlet (11) connected to an exhaust port of the engine, and a partition plate. The second expansion chamber (15) partitioned from the first expansion chamber (12) through (14) and the second expansion port (16) of the partition plate (14) through the second expansion port (16). A third expansion chamber (18) having an exhaust gas outlet (17) communicating with the chamber (15), and the exhaust gas inlet (11) is provided with a first heat-resistant mesh catalyst (19). The partition plate (14) having an exhaust gas outlet (14c) is integrally formed with a projection (14d) projecting toward the second expansion chamber (15), and a first of the projection (14d) is formed. Exhaust gas to the heat-resistant knitted fabric (20a) on the exhaust gas inlet side of the expansion chamber (12) side A first exhaust gas purifier having a catalyst coated thereon to be coated and covered with a heat-resistant cover (20b) having at least one exhaust gas inlet (20d) from the first expansion chamber (12) side (20) is provided.

  Still another embodiment of the muffler for a small engine of the present invention includes a first expansion chamber (12) for exhaust gas having an exhaust gas inlet (11) connected to an exhaust port of the engine, The exhaust gas inlet (11) has a first expansion chamber (12) and a second expansion chamber (15) partitioned through a partition plate (14) having a vent (13). The first heat-resistant mesh catalyst (19) is provided, and the first vent (13) of the partition plate (14) is coated with a heat-resistant knitted fabric (20a) with a catalyst for purifying exhaust gas. Provided with a first exhaust gas purifier (20), communicated with the second expansion chamber (15), and a portion facing the first exhaust gas purifier (20) is a double pipe. The one end of the double pipe communicates with the outside air through the outer wall, and the double pipe outer pipe (30a A plurality of suction holes (30b) are formed in the outside, and an outside air suction pipe (30) having the other end communicating with the exhaust gas outlet 17 through an exhaust gas guide (33) is provided. is there.

  According to still another embodiment of the muffler for a small engine of the present invention, the exhaust gas guide (33) has a pipe (34) communicating with the first expansion chamber (12) of the exhaust gas. The pipe (34) is provided with a check valve (35).

  Still another embodiment of the muffler for a small engine of the present invention includes a first expansion chamber (12) for exhaust gas having an exhaust gas inlet (11) connected to an exhaust port of the engine, The exhaust gas inlet (11) has a first expansion chamber (12) and a second expansion chamber (15) partitioned through a partition plate (14) having a vent (13). The first heat-resistant mesh catalyst (19) is provided, and the first vent (13) of the partition plate (14) is coated with a heat-resistant knitted fabric (20a) with a catalyst for purifying exhaust gas. Provided with a first exhaust gas purifier (20), an exhaust gas guide (33) communicating with the second expansion chamber (15) and the exhaust gas outlet 17, the exhaust gas guide ( 33) also communicates with the first expansion chamber (12) of the exhaust gas. Forming a type (34) and is characterized in that a check valve (35) to the pipe (34).

  Still another embodiment of the muffler for a small engine according to the present invention is the muffler according to one embodiment, the other embodiment, or another embodiment of the present invention, wherein one end of the groove is the above-described one. A groove (31) communicating with the third expansion chamber (18) and the other end communicating with the outside air is formed on the outer wall of the muffler, and a groove cover (32) covering the groove (31) is provided. It is a feature.

  Still another embodiment of a muffler for a small engine according to the present invention is the muffler according to one embodiment, another embodiment, or another embodiment of the present invention, in which the outside air is opened at both ends. The outside air suction pipe (30 ') is fixed along the outer wall of the muffler so that one end of the suction pipe (30') communicates with the exhaust gas outlet (17) and the other end communicates with outside air. It is a feature.

It is sectional drawing which concerns on one Embodiment of the muffler for small engines of this invention. 1 is an exploded perspective view according to an embodiment of a muffler for a small engine of the present invention. 1 is an assembled perspective view according to an embodiment of a muffler for a small engine of the present invention. It is sectional drawing of the muffler which made the 1st exhaust gas purifier which is the structural member which concerns on one Embodiment of the muffler for small engines of this invention into other embodiment. It is a disassembled perspective view of the muffler which made the 1st exhaust-gas purifier which is the structural member which concerns on one Embodiment of the muffler for small engines of this invention into other embodiment. It is the assembly perspective view of the muffler which made the 1st exhaust-gas purifier which is the structural member which concerns on one Embodiment of the muffler for small engines of this invention to other embodiment. 1 is a cross-sectional view of a muffler having a double structure on an outer wall of a muffler in a configuration according to an embodiment of a muffler for a small engine of the present invention. FIG. 8 is a cross-sectional view of the muffler in which a heat insulating material is inserted between outer walls of a double structure in the muffler having the structure shown in FIG. 7. In the muffler having the structure shown in FIG. 7, the first exhaust gas purifier is a cross-sectional view of a muffler according to another embodiment. FIG. 10 is a cross-sectional view of the muffler in which a heat insulating material is inserted between outer walls of a double structure in the muffler having the structure shown in FIG. 9. It is sectional drawing which concerns on other embodiment of the muffler for small engines of this invention. In the muffler having the structure shown in FIG. 11, the first exhaust gas purifier is a cross-sectional view of a muffler according to another embodiment. It is sectional drawing which concerns on other embodiment of the muffler for small engines of this invention. It is sectional drawing which concerns on other embodiment of the muffler for small engines of this invention. It is sectional drawing which concerns on other embodiment of the muffler for small engines of this invention. It is sectional drawing which concerns on other embodiment of the muffler for small engines of this invention. It is sectional drawing which concerns on other embodiment of the muffler for small engines of this invention. It is a disassembled perspective view which concerns on other embodiment of the muffler for small engines of this invention. It is a disassembled perspective view which concerns on other embodiment of the muffler for small engines of this invention. It is a disassembled perspective view which concerns on other embodiment of the muffler for small engines of this invention. It is sectional drawing of the muffler for the conventional small engines. It is sectional drawing of the muffler for other conventional small engines.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a sectional view according to an embodiment of a muffler for a small engine of the present invention. 2 is an exploded perspective view, and FIG. 3 is an assembled perspective view.
A muffler for a small engine according to an embodiment of the present invention includes a first expansion chamber 12 for exhaust gas having an exhaust gas inlet 11 connected to an exhaust port of the engine, and the first expansion chamber 12 via a partition plate 14. A second expansion chamber 15 for exhaust gas which is partitioned from the expansion chamber 12 and communicates with the first expansion chamber 12 through the first vent 13 of the partition plate 14, and the partition plate 14 through the partition plate 14. A third expansion chamber 18 of exhaust gas having an exhaust gas outlet 17, which is separated from the second expansion chamber 15 and communicates with the second expansion chamber 15 through the second vent 16 of the partition plate 14; Is provided. The exhaust gas inlet 11 is provided with a first heat-resistant mesh catalyst 19, and the first vent 13 of the partition plate 14 is coated with a catalyst for purifying exhaust gas on the heat-resistant knitted fabric 20a. A first exhaust gas purifier 20 made of a material is provided.

  The first exhaust gas purifier 20 is a stainless steel heat resistant knitted fabric 20a coated with a catalyst for purifying exhaust gas, and is made of stainless steel having at least one exhaust gas inlet 20d. It is configured to be held by the cover 20b.

  The first exhaust gas purifier 20 is provided on the exhaust gas inlet side of the first vent 13 of the partition plate 14, the second heat-resistant mesh catalyst 21 is provided on the outlet side thereof, and a plurality of exhaust gases are provided. A heat-resistant cover 22 having a gas outlet 22a is provided, and a third heat-resistant mesh catalyst 23 is provided at the exhaust gas outlet 17 in a replaceable manner.

  The heat-resistant cover 20b and the heat-resistant cover 22 can be made by press-molding a stainless steel plate, and this is attached to the first vent 13 of the partition plate 14 by welding.

  The outer wall 12a of the first extension chamber 12, the outer wall 15a of the second extension chamber 15, the partition plate 14, and the partition plate 14 and the outer wall 12a of the first extension chamber 12 are installed by welding. The partition plate 18a forming the third expansion chamber 18 is formed by molding a stainless steel plate.

  An outer wall 12a of the first extension chamber 12, an outer wall 15a of the second extension chamber 15, the partition plate 14, a partition plate 18a forming a third extension chamber 18, and the heat resistant cover 20b. When the heat resistant cover 22 is made of stainless steel, preferably SUS310s stainless steel, the heat resistant cover 22 is excellent in heat resistance and acid resistance, and the life can be extended.

  Further, the first heat-resistant mesh catalyst 19, the second heat-resistant mesh catalyst 21, and the third heat-resistant mesh catalyst 23 are made of a stainless steel wire mesh or a stainless steel plate with a large number of pores. For example, platinum, rhodium, palladium, etc., or a combination of two or more catalysts for purifying exhaust gas is coated, and the stainless steel is preferably SUS310s stainless steel, When steel is used, it has excellent heat resistance and acid resistance, and can extend its life.

The heat-resistant knitted fabric 20a is made by coating the catalyst for purifying exhaust gas on a knitted one or several wires made of stainless steel and folded to a desired thickness. .
The heat-resistant knitted fabric 20a is easier to manufacture and lower in manufacturing cost than the conventional manufacturing of a honeycomb-shaped substrate made of stainless steel.

  As shown in FIGS. 1, 2, and 3, the inside of the muffler is divided into a first expansion chamber 12, a second expansion chamber 15, and a third expansion chamber 18 through a partition plate 14. , Mute effect is improved. In addition, since the first heat-resistant mesh catalyst 19 is provided at the exhaust gas inlet 11, the spark contained in the exhaust of the engine does not enter the muffler (so-called spark arrester effect). The first exhaust gas purifier 20 provided in the first vent 13 formed in the partition plate 14 so that the first expansion chamber 12 and the second expansion chamber 15 communicate with each other is heat resistant. Since the knitted fabric 20a is formed by coating the catalyst for purifying the exhaust gas, its manufacture is simple and the manufacturing cost is reduced.

  The second heat-resistant mesh catalyst 21 is made by coating a stainless steel mesh with the catalyst for purifying exhaust gas, and this is welded to the partition plate 14. The third heat-resistant mesh catalyst 23 is made by coating a stainless steel mesh with the catalyst for purifying exhaust gas. When the stainless steel is preferably SUS310s stainless steel, it has excellent heat resistance and acid resistance, and can extend its life.

  FIG. 4 is a cross-sectional view of a muffler in which the first exhaust gas purifier 20 is another embodiment, FIG. 5 is an exploded perspective view thereof, and FIG. 6 is an assembled perspective view thereof. The container 20 is formed by holding a heat-resistant knitted fabric 20a coated with the catalyst for purifying exhaust gas, and holding it with a heat-resistant cover 20c formed of a heat-resistant mesh. The heat-resistant mesh may be a stainless steel mesh coated with the catalyst for purifying exhaust gas, and a heat-resistant cover 20c made of the heat-resistant mesh is attached to the partition plate 14 by welding. . When the stainless steel is preferably SUS310s stainless steel, it has excellent heat resistance and acid resistance, and can extend its life.

  As described above, the first vent 13 formed in the partition plate 14 is provided with the first exhaust gas purifier 20 on the exhaust gas inlet side, and the second heat-resistant mesh is provided on the outlet side thereof. Since the catalyst 21 is provided and the heat-resistant cover 22 having a plurality of exhaust gas outlets 22a is provided, the first exhaust gas purifier 20 is quickly heated and the temperature is increased, thereby further purifying the exhaust gas. Get better. In addition, since the third heat-resistant mesh catalyst 23 is replaceably provided at the exhaust gas outlet 17, it is possible to prevent sparks from coming out of the muffler, and the third heat-resistant mesh catalyst 23 is It can be easily replaced.

  As shown in FIGS. 7 and 9, at least the wall of the second expansion chamber 15 that is not attached to the engine may be formed by double walls 15a ′ and 15b.

  Further, as shown in FIGS. 8 and 10, at least the wall of the second expansion chamber 15 which is not attached to the engine is formed by double walls 15a ′ and 15b, and a heat insulating material 15c is filled between the double walls. May be configured.

  By configuring as described above, heating of the outer wall of the muffler is prevented. Furthermore, the effect of preventing the heating of the outer wall of the muffler is further improved by filling the insulating material 15c between the double walls.

In another embodiment of the present invention, as shown in FIGS. 11 and 12, an exhaust gas receiving member 24 is provided in the first expansion chamber 12 facing the exhaust gas inlet 11 connected to the exhaust port of the engine. It may be provided. The exhaust gas receiving member 24 is connected to the exhaust gas inlet 11 and includes an exhaust port 24 b facing the exhaust gas inlet 11. The exhaust gas receiving member 24 has a heat resistance in the vicinity of the exhaust port 24 b. A second exhaust gas purifier 25 in which the catalyst for purifying the exhaust gas is coated on the knitted fabric is accommodated, and the exhaust port 24b is inclined so that the exhaust gas flows in the direction of the first exhaust gas purifier 20. A surface 24a is formed.
After the second exhaust gas purifier 25 is accommodated in the exhaust gas receiving member 24, the second exhaust gas purifier 25 is deformed by projecting inwardly in the middle of the exhaust gas receiving member 24. It is held so that it cannot be removed.
When the exhaust gas receiving member 24 is preferably made of SUS310s stainless steel, it has excellent heat resistance and acid resistance, and can extend its life.

  With the above configuration, the first exhaust gas exhausted from the engine is received by the exhaust gas receiving member 24 and purified by the second exhaust gas purifier 25 provided here. Gas purification is further improved.

  The first heat-resistant mesh catalyst 19 is configured by coating the catalyst for purifying exhaust gas on a mesh made of SUS310s stainless steel, so that the first heat-resistant mesh catalyst 19 is heat-resistant. In addition, it has excellent acid resistance and can extend the life.

  The second heat-resistant mesh catalyst 21 is formed by coating the catalyst for purifying exhaust gas on a mesh made of SUS310s stainless steel, and the heat-resistant cover 22 is formed by a SUS310s stainless steel plate. The third heat-resistant mesh catalyst 23 is formed by coating the catalyst for purifying exhaust gas on a mesh made of SUS310s stainless steel, so that it has excellent heat resistance and acid resistance and can achieve a long life. .

  The exhaust gas receiving member 24 is formed of a SUS310s stainless steel plate, and a second exhaust gas purifier 25 coated with the catalyst for purifying exhaust gas on a heat-resistant knitted fabric made of stainless steel. By adopting the housed configuration, the exhaust gas receiving member 24 and the second exhaust gas purifier 25 are excellent in heat resistance and acid resistance, and can extend their life.

  Further, in another embodiment of the muffler for a small engine of the present invention, as shown in FIG. 13, the first expansion chamber 12 has at least one first vent hole 14a in the partition plate 14. A first exhaust gas in which a convex portion 14b protruding to the side is integrally formed, and a heat-resistant knitted fabric 20a is coated with the catalyst for purifying the exhaust gas in a concave portion on the second expansion chamber 15 side of the convex portion 14b. A heat-resistant cover 22 having an exhaust gas outlet 22a that covers the first exhaust gas purifier 20 from the second expansion chamber 15 side is provided, and the first exhaust gas purifier 20 is installed. Since it comprised, the structure of the 1st exhaust gas purifier 20 becomes easy, and it can manufacture at low cost. The exhaust gas outlet 22 a is provided so that the exhaust gas does not flow in the direction of the outer wall 15 a of the second expansion chamber 15 but flows along the partition plate 14.

  Further, in another embodiment of the muffler for a small engine according to the present invention, as shown in FIG. 14, the partition plate 14 has an exhaust gas outlet 14c and protrudes toward the second expansion chamber 15. The part 14d is integrally formed, and the heat-resistant knitted fabric 20a coated with the catalyst for purifying the exhaust gas is attached to the inlet side of the concave part on the first expansion chamber 12 side of the convex part 14d. Since the first exhaust gas purifier 20 provided with the heat-resistant cover 20b having at least one exhaust gas inlet 20d from the first expansion chamber 12 side is provided, the first exhaust gas purifier 20 is configured. The structure becomes easy and can be manufactured at low cost. The exhaust gas outlet 14 c is provided so that the exhaust gas does not flow in the direction of the outer wall 15 a of the second expansion chamber 15 but flows along the partition plate 14.

Further, as shown in FIG. 15, another embodiment of the muffler for a small engine of the present invention includes a first expansion chamber 12 for exhaust gas having an exhaust gas inlet 11 connected to an exhaust port of the engine, A first expansion chamber 12 and a second expansion chamber 15 partitioned by a partition plate 14 having a single vent 13, and the exhaust gas inlet 11 has a first heat-resistant mesh catalyst. 19, the first vent 13 of the partition plate 14 is provided with a first exhaust gas purifier 20 made of a heat-resistant knitted fabric 20a coated with the catalyst for purifying exhaust gas, A portion that communicates with the second expansion chamber 15 and faces the first exhaust gas purifier 20 is a double pipe, one end of which communicates with the outside air through the outer wall. A plurality of suction holes 30b are formed in 30a, and the other end Communicating with the exhaust gas outlet 17 via the exhaust gas guide 33 is obtained by arranging the outside air suction pipe 30.
In the embodiment shown in FIG. 15, the first exhaust gas purifier 20 is formed by holding the heat-resistant knitted fabric 20a with a heat-resistant cover 20c formed of a heat-resistant mesh. The exhaust gas purifier 20 may be formed by holding the heat resistant knitted fabric 20a with a heat resistant cover 20b having at least one exhaust gas inlet 20d as shown in FIG.

  Since such an outside air suction pipe 30 is provided, the exhaust gas that has passed through the first exhaust gas purifier 20 passes through a suction hole 30b formed in the outer pipe 30a of the double pipe of the outside air suction pipe 30. It enters the outer pipe 30 a and flows through the outside air suction pipe 30 to the exhaust gas outlet 17. Then, since the exhaust gas in the outside air suction pipe 30 is sucked, outside air is sucked into the outside air suction pipe 30 from the outside air suction port 30c at the other end of the outside air suction pipe 30, and is discharged from the exhaust gas outlet 17. The exhaust gas temperature decreases.

Still another embodiment of the muffler for a small engine of the present invention is, as shown in FIG. 16, a pipe 34 communicating with the exhaust gas guide 33 also in the first expansion chamber 12 of the exhaust gas. And a check valve 35 is provided on the pipe 34.
The non-return valve 35 may be a butterfly valve as shown in FIG. 5B, or a pipe 34 having a small end as shown in FIG.
With this configuration, the outside air (oxygen) flows into the first expansion chamber 12 through the outside air suction pipe 30 and the check valve 35 provided in the pipe 34 formed in the exhaust gas guide 33. The combustion efficiency in which the exhaust gas in the first expansion chamber 12 is combusted by the first exhaust gas purifier 20 is improved, and a part of the exhaust gas enters the first expansion chamber 12 again, Since the exhaust gas purifier 20 is reburned, the exhaust gas purification action is improved.

Still another embodiment of the muffler for a small engine of the present invention is, as shown in FIG. 17, an exhaust gas first expansion chamber 12 having an exhaust gas inlet 11 connected to an exhaust port of the engine, The first expansion chamber 12 is separated from the first expansion chamber 12 through a partition plate 14 having a first vent hole 13. The exhaust gas inlet 11 has a first heat-resistant mesh. A catalyst 19 is provided, and the first vent 13 of the partition plate 14 is provided with a first exhaust gas purifier 20 made of a heat-resistant knitted fabric 20a coated with the catalyst for purifying the exhaust gas. An exhaust gas guide 33 is provided for communicating the second expansion chamber 15 and the exhaust gas outlet 17, and a pipe 34 communicating with the first expansion chamber 12 for the exhaust gas is provided in the exhaust gas guide 33. Form and check this pipe 34 It is provided with a 35.
The check valve 35 may be a butterfly valve as shown in (b), or a pipe 34 with a small end as shown in (c). Further, as shown in FIG. 4 (d), a pipe 34 communicating with the first expansion chamber 12 may be provided separately from the exhaust gas guide 33, and a check valve 35 may be provided at the tip of the pipe 34. .
With this configuration, a part of the exhaust gas in the second expansion chamber 15 flows again into the first expansion chamber 12 through the pipe 34 and the check valve 35, and again the first exhaust gas. Since it is burned by the gas purifier 20, the exhaust gas purification action is improved.

  Furthermore, as shown in FIG. 18, in another embodiment of the muffler for a small engine of the present invention, one end of the groove communicates with the third expansion chamber 18 (see FIG. 1) and the other end is outside air. Since the muffler for a small engine is provided with a groove 31 that is formed on the outer wall of the muffler and a groove cover 32 that covers the groove 31 is provided, the exhaust gas from the third expansion chamber 18 is exhausted. Since the outside air is sucked into the third expansion chamber 18 by being sucked into the exhaust gas exhausted through the outlet 17 and from the concave groove 31 formed in the outer wall of the muffler, the exhaust gas discharged from the exhaust gas outlet 17 The temperature goes down. Here, as shown in FIG. 19, the groove cover covering the concave groove 31 includes a lattice member 28 ′ covering the exhaust gas outlet 17 of the third expansion chamber 18 and a groove cover 32 ′ covering the concave groove 31. It can be formed integrally.

  In addition, as shown in FIG. 20, in another embodiment of the muffler for a small engine of the present invention, one end of an outside air suction pipe 30 'having both ends opened communicates with the exhaust gas outlet 17, and the other end has Since the muffler of the small engine is characterized in that the outside air suction pipe 30 'is fixed along the outer wall of the muffler so as to communicate with the outside air, the exhaust gas is exhausted from the third expansion chamber 18 (see FIG. 1). Since the outside air is sucked into the third expansion chamber 18 from the other end of the outside air suction pipe 30 ′ by being sucked by the exhaust gas exhausted through the gas outlet 17, the exhaust gas discharged from the exhaust gas outlet 17 The temperature drops. The outside air suction pipe 30 'can be fixed along the outer wall of the muffler by means such as welding.

As shown in FIGS. 1, 3, 4, 6, and 11 to 17, the outer walls 12a and 15a and the end portions of the partition plate 14 are fixed by caulking.
As shown in FIGS. 7 to 10, the double walls 15 a, 15 b forming the double walls 12 a, 12 b of the first expansion chamber, the partition plate 14, and the second expansion chamber 15 are formed. The edge is fixed by caulking.

  Moreover, the code | symbol 26 shown in FIGS. 1-6, FIGS. 11-20 was constructed between the outer wall 12a which forms the 1st expansion chamber 12, and the outer wall 15a which forms the 2nd expansion chamber 15, A pipe member into which bolts 27 for fixing the muffler to the engine are inserted, reference numeral 28 is a lattice member, and this lattice member 28 is detachably attached to the outer wall 12a of the muffler by an attachment screw 29, and by removing this, The third heat resistant mesh catalyst 23 can be replaced.

Claims (17)

A first expansion chamber (12) for exhaust gas having an exhaust gas inlet (11) connected to the exhaust port of the engine is partitioned from the first expansion chamber (12) via a partition plate (14). A second expansion chamber (15) for exhaust gas communicating with the first expansion chamber (12) through the first vent (13) of the partition plate (14) and the partition plate (14). And an exhaust gas outlet (17) that is separated from the second expansion chamber (15) and communicates with the second expansion chamber (15) through the second vent (16) of the partition plate (14). A third expansion chamber (18) of exhaust gas having
The exhaust gas inlet (11) is provided with a first heat-resistant mesh catalyst (19), and the first vent (13) of the partition plate (14) is exhausted to the heat-resistant knitted fabric (20a). A muffler for a small engine, comprising a first exhaust gas purifier (20) made of a coating of a catalyst for purifying gas.   The first exhaust gas purifier (20) includes a heat resistant knitted fabric (20a) coated with a catalyst for purifying exhaust gas, and a heat resistant cover (20b) having at least one exhaust gas inlet (20d). The muffler for a small engine according to claim 1, wherein the muffler is formed by holding the   The first vent (13) of the partition plate (14) is provided with the first exhaust gas purifier (20) on the inlet side of the exhaust gas, and the second heat-resistant mesh catalyst ( 21), a heat-resistant cover (22) having a plurality of exhaust gas outlets (22a), and a third heat-resistant mesh catalyst (23) replaceably provided at the exhaust gas outlet (17). The muffler for a small engine according to claim 1, wherein the muffler is for a small engine.   The first exhaust gas purifier (20) is formed by holding a heat-resistant knitted fabric (20a) coated with a catalyst for purifying exhaust gas and holding it with a heat-resistant cover (20c) formed of a heat-resistant mesh. The muffler for a small engine according to claim 1, wherein the muffler is for a small engine.   The small wall according to claim 1 or 4, characterized in that at least the outer wall of the second expansion chamber (15) not on the side attached to the engine is formed of a double wall (15a ', 15b). Muffler for engine.   At least the outer wall of the second expansion chamber (15) which is not attached to the engine is formed of a double wall (15a ', 15b), and a heat insulating material (15c) is filled between the double walls. A muffler for a small engine according to claim 1 or claim 4.   An exhaust gas receiving member (24) is provided in the first expansion chamber (12) facing the exhaust gas inlet (11), and the exhaust gas receiving member (24) is connected to the exhaust gas inlet (11). In addition, an exhaust port (24b) facing the exhaust gas inlet (11) is provided, and a catalyst for purifying the exhaust gas is provided in a heat-resistant knitted fabric in the vicinity of the exhaust port (24b) inside the exhaust gas receiving member (24). The coated second exhaust gas purifier (25) is accommodated, and the exhaust port (24b) has an inclined surface (24a) so that the exhaust gas flows in the direction of the first exhaust gas purifier (20). The muffler for a small engine according to claim 1 or 4, wherein the muffler is formed.   The first heat-resistant mesh catalyst (19) is formed by coating a SUS310s stainless steel mesh with a catalyst for purifying exhaust gas. The muffler for the described small engine.   The second heat-resistant mesh catalyst (21) is made of SUS310s stainless steel mesh coated with a catalyst for purifying exhaust gas, and the heat-resistant cover (22) is made of SUS310s stainless steel plate. The third heat-resistant mesh catalyst (23) is formed by coating a SUS310s stainless steel mesh with a catalyst for purifying exhaust gas. Muffler for small engines.   The muffler for a small engine according to claim 7, wherein the exhaust gas receiving member (24) is formed of a SUS310s stainless steel plate. A first expansion chamber (12) for exhaust gas having an exhaust gas inlet (11) connected to the exhaust port of the engine, and a first expansion chamber (12) partitioned by a partition plate (14). A third expansion chamber having two expansion chambers (15) and an exhaust gas outlet (17) communicating with the second expansion chamber (15) through the second vent (16) of the partition plate (14). (18)
The first expansion is provided with a first heat-resistant mesh catalyst (19) at the exhaust gas inlet (11), and at least one first vent (14a) in the partition plate (14). A convex part (14b) protruding toward the chamber (12) is formed integrally, and exhaust gas is supplied to the heat-resistant knitted fabric (20a) in the concave part on the second expansion chamber (15) side of the convex part (14b) A first exhaust gas purifier (20) coated with a catalyst to be purified is mounted, and an exhaust gas outlet (22a) covering the first exhaust gas purifier (20) from the second expansion chamber (15) side is provided. A muffler for a small engine, characterized in that a heat-resistant cover (22) is provided. A first expansion chamber (12) for exhaust gas having an exhaust gas inlet (11) connected to the exhaust port of the engine, and a first expansion chamber (12) partitioned by a partition plate (14). A third expansion chamber having two expansion chambers (15) and an exhaust gas outlet (17) communicating with the second expansion chamber (15) through the second vent (16) of the partition plate (14). (18)
The exhaust gas inlet (11) is provided with a first heat-resistant mesh catalyst (19), and the partition plate (14) has an exhaust gas outlet (14c) on the second expansion chamber (15) side. A projecting projection (14d) is integrally formed, and the heat-resistant knitted fabric (20a) purifies the exhaust gas on the exhaust gas inlet side on the first expansion chamber (12) side of the projection (14d). A first exhaust gas purifier (20) covered with a heat resistant cover (20b) having at least one exhaust gas inlet (20d) from the first expansion chamber (12) side. A muffler for small engines. The first expansion chamber (12) having an exhaust gas inlet (11) connected to the exhaust port of the engine and the partition plate (14) having a first vent (13) are used for the first gas. An expansion chamber (12) and a second expansion chamber (15) partitioned;
The exhaust gas inlet (11) is provided with a first heat-resistant mesh catalyst (19), and the first vent (13) of the partition plate (14) is exhausted to the heat-resistant knitted fabric (20a). Providing a first exhaust gas purifier (20) made of a coating of a gas purifying catalyst;
A portion that communicates with the second expansion chamber (15) and faces the first exhaust gas purifier (20) is a double pipe, one end of which communicates with the outside air through the outer wall. A plurality of suction holes (30b) are formed in the outer pipe (30a) of the pipe, and an outside air suction pipe (30) whose other end communicates with the exhaust gas outlet 17 via the exhaust gas guide (33) is disposed. A muffler for small engines.   The exhaust gas guide (33) is formed with a pipe (34) communicating with the first expansion chamber (12) of the exhaust gas, and a check valve (35) is provided on the pipe (34). The muffler for small engines of Claim 14 characterized by these. The first expansion chamber (12) having an exhaust gas inlet (11) connected to the exhaust port of the engine and the partition plate (14) having a first vent (13) are used for the first gas. An expansion chamber (12) and a second expansion chamber (15) partitioned;
The exhaust gas inlet (11) is provided with a first heat-resistant mesh catalyst (19), and the first vent (13) of the partition plate (14) is exhausted to the heat-resistant knitted fabric (20a). An exhaust gas guide (33) provided with a first exhaust gas purifier (20) made of a coating of a catalyst for purifying gas and communicating between the second expansion chamber (15) and the exhaust gas outlet 17 is provided. ) And a pipe (34) communicating with the first expansion chamber (12) of the exhaust gas is formed in the exhaust gas guide (33), and a check valve (35) is formed in the pipe (34). A muffler for small engines.   The muffler for a small engine according to any one of claims 1, 11, 12 and 15, wherein one end of the groove communicates with the third expansion chamber (18) and the other end communicates with the outside air. A muffler for a small engine, wherein a groove (31) is formed on an outer wall of the muffler, and a groove cover (32) is provided to cover the groove (31).   The muffler for a small engine according to any one of claims 1, 11, 12 and 15, wherein one end of an outside air suction pipe (30 ') having both ends opened communicates with the exhaust gas outlet (17). A muffler for a small engine, wherein the outside air suction pipe (30 ') is fixed along the outer wall of the muffler so that the other end communicates with outside air.

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