JP3955293B2 - Muffler with catalyst for internal combustion engine - Google Patents

Muffler with catalyst for internal combustion engine Download PDF

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Publication number
JP3955293B2
JP3955293B2 JP2004231133A JP2004231133A JP3955293B2 JP 3955293 B2 JP3955293 B2 JP 3955293B2 JP 2004231133 A JP2004231133 A JP 2004231133A JP 2004231133 A JP2004231133 A JP 2004231133A JP 3955293 B2 JP3955293 B2 JP 3955293B2
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Prior art keywords
panel
catalyst
expansion chamber
muffler
diffuser
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Expired - Fee Related
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JP2004231133A
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JP2006046264A (en
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和弘 筒井
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株式会社共立
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/18Construction facilitating manufacture, assembly, or disassembly
    • F01N13/1833Construction facilitating manufacture, assembly, or disassembly specially adapted for small internal combustion engines, e.g. used in model applications
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N1/00Silencing apparatus characterised by method of silencing
    • F01N1/08Silencing apparatus characterised by method of silencing by reducing exhaust energy by throttling or whirling
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/002Apparatus adapted for particular uses, e.g. for portable devices driven by machines or engines
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/28Construction of catalytic reactors
    • F01N3/2882Catalytic reactors combined or associated with other devices, e.g. exhaust silencers or other exhaust purification devices
    • F01N3/2885Catalytic reactors combined or associated with other devices, e.g. exhaust silencers or other exhaust purification devices with exhaust silencers in a single housing
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2230/00Combination of silencers and other devices
    • F01N2230/04Catalytic converters
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2590/00Exhaust or silencing apparatus adapted to particular use, e.g. for military applications, airplanes, submarines
    • F01N2590/06Exhaust or silencing apparatus adapted to particular use, e.g. for military applications, airplanes, submarines for hand-held tools or portables devices

Description

  The present invention relates to a muffler provided with an expansion chamber and an exhaust gas purifying catalyst, and more particularly, to a muffler with a catalyst suitable for use in a small air-cooled two-cycle gasoline engine or the like used in a portable working machine such as a brush cutter or a chain saw.

  In recent years, internal combustion engines such as small air-cooled two-cycle gasoline engines used in portable work machines such as brush cutters and chain saws, as well as in-vehicle engines, are used in hydrocarbons (HC) and carbon monoxide in exhaust gas. There has been a strong demand to reduce (CO) and the like, and therefore, an exhaust gas purification catalyst is disposed in a muffler provided in the exhaust system, and exhaust gas is passed through the catalyst to purify exhaust gas (HC, It has been proposed to reduce CO and the like.

  In such a muffler with a catalyst, for example, as seen in Patent Document 1 below, the muffler expansion chamber is partitioned into a first expansion chamber and a second expansion chamber by a partition panel, and exhaust gas purification is performed in the partition panel. The catalyst is mounted so as to face both the expansion chambers, exhaust gas is ejected from the exhaust port of the internal combustion engine to the first expansion chamber, and exhaust gas is ejected from the first expansion chamber through the catalyst to the second expansion chamber. It is known that it is led to a chamber and discharged to the outside through an outlet provided in the second expansion chamber.

  In addition, the mounting of the muffler to the engine (cylinder thereof) has conventionally been performed using relatively long bolts having such a length that can traverse the muffler, as can be seen in Patent Document 2 below. The outside of the muffler (the outer wall panel) is performed.

  Furthermore, recently, instead of attaching the catalyst to the partition panel, a catalyst holding body (diffuser) is separately prepared, and the catalyst is held and fixed to the diffuser.

  A muffler with a catalyst provided with such a diffuser will be described with reference to FIG. In FIG. 9, the internal combustion engine 1 ′ is a small air-cooled two-cycle gasoline engine of the Schnure scavenging type incorporated as a power source of a portable work machine such as a brush cutter or a chainsaw, and the displacement is about 23 to 45 mL, for example. It is about. The engine 1 'includes a cylinder 2' having a hemispherical combustion chamber 5 '. The cylinder 2' is provided with a large number of cooling fins 6 'on the outer periphery, and from the inner end side to the outer end side. An exhaust port 10 ′ having a divergent shape with a gradually increasing cross-sectional area is provided (the cross section is, for example, an oval shape), and further, although not illustrated, an intake port and a scavenging port are provided in a known manner.

  A muffler 20 'is attached to the outer side of the cylinder 2' on the exhaust port 10 'side. The muffler 20 ′ includes front and rear outer wall panels 21 ′ and 22 ′ which are hermetically joined by a helix folding process, and an expansion chamber 25 ′ is defined by the outer wall panels 21 ′ and 22 ′. An opening 21a ′ having substantially the same shape as the outer end of the exhaust port 10 ′ is formed in the front outer wall panel 21 ′ located on the exhaust port 10 ′ side, and a reinforcing plate 28 is formed around the opening 21a ′. 'Is attached by welding or the like. Further, a recess 22a ′ is provided directly opposite the exhaust port 10 ′ in the rear outer wall panel 22 ′, and a bottomed rectangular tube shape is formed so as to bridge the recess 22a ′ and the reinforcing plate 28 ′. A diffuser (catalyst holder) 40 'is installed.

  A mounting hole 40a ′ for fitting and holding a short columnar exhaust purification catalyst 30 ′ by welding or the like is provided on the inner end 41 ′ side (the exhaust port 10 ′ side) of the diffuser 40 ′. In addition, a required number of exhaust gas insertion holes 43 ′ are provided on the outer end portion 42 ′ side (the concave portion 22 a ′ side) of the diffuser 40 ′. The catalyst 30 'is a metal carrier oxidation catalyst having air permeability, and a cylindrical shell 32' is packaged on the outer periphery thereof. The catalyst 30 ′ is held by the diffuser 40 ′ so that the center axis O thereof substantially coincides with the exhaust port 10 ′ (outer end portion thereof) and the center line of the diffuser 40 ′.

  In addition, an outlet 29 ′ for discharging exhaust gas to the outside is provided at the lower portion of the rear outer wall panel 22 ′. The outlet 29 ′ is not shown, but is made of a metal spark arrester screen (SAM). Screen), an exhaust gas guide member for regulating the exhaust gas discharge direction, and the like.

Under such a configuration, the exhaust gas ejected from the exhaust port 10 ′ at a speed close to the sound speed is the diffuser 40 disposed in the muffler 20 ′ as indicated by the solid line arrow in FIG. 9. It is guided to the catalyst 30 ′ through the “inner end portion 41 ′” and passes through the inside thereof. At that time, HC, CO and the like in the exhaust gas are reduced by the catalyst 30 '. The exhaust gas that has passed through the catalyst 30 'is blown into the expansion chamber 25' through the exhaust gas insertion hole 43 'of the diffuser 40' to be expanded and diffused, whereby the exhaust sound is attenuated. The exhaust gas expanded and diffused in the expansion chamber 25 ′ moves downward and is discharged to the outside through the outlet 29 ′.
JP 2001-317325 A Japanese National Patent Publication No. 9-507898

  However, the conventional muffler with a catalyst described above is expensive to manufacture because the welding and copper brazing are frequently used to hold and fix the outer wall panel, partition panel, diffuser, catalyst, etc. before and after the expansion chamber. I hate being.

  Further, since the attachment of the muffler to the cylinder is performed from the outside of the muffler (the outer wall panel) using relatively long bolts, the tightening fixing position is considerably separated from the cylinder. . As a result, the mounting stability and rigidity of the muffler are likely to be low, and holes for inserting bolts and the like are required, so that the structure of the outer wall panel and the like is complicated.

  Further, in the case of having a diffuser as shown in FIG. 9, it is necessary to provide a mounting hole or the like in the diffuser in order to hold and fix the catalyst to the diffuser. 10, the cross-sectional shape of the catalyst 30 ′ differs from the opening shape of the exhaust port 10 ′ and the cross-sectional shape of the diffuser 40 ′ (inner end portion 41 ′). However, there is a problem that the exhaust gas hardly passes through the upper and lower ends of the catalyst 30 ′, and the purification ability of the catalyst 30 ′ is not fully utilized. .

  In addition, since the spark arrester screen and the exhaust gas guide member are screwed to the outlet 29 ′ provided in the rear outer wall panel 22 ′, the number of parts (screws) increases and the outlet Restrictions are imposed on the position and shape of 29 ', and the degree of freedom in design is low.

  The present invention has been made in view of the conventional problems as described above. The object of the present invention is to reduce the number of welding points and to suppress the manufacturing cost as much as possible, and to have a relatively simple configuration. Can be mounted and fixed directly to the cylinder without using long bolts, improving the mounting stability and rigidity, etc., and making full use of the purification capacity of the catalyst Another object of the present invention is to provide a muffler with a catalyst for an internal combustion engine that can increase the degree of freedom in designing the position and shape of the exhaust gas outlet.

In order to achieve the above object, the muffler with a catalyst for an internal combustion engine according to the present invention basically has an expansion chamber defined by a cup-shaped front outer wall panel and a rear outer wall panel that are separable from each other. The expansion chamber is partitioned into a first expansion chamber and a second expansion chamber by a partition panel disposed between the front outer wall panel and the rear outer wall panel, and a bottomed cylinder is formed in the first expansion chamber. A diffuser having a gas-like shape is disposed, and an exhaust gas purifying catalyst having air permeability is inserted and fixed in the diffuser, and exhaust gas ejected from an exhaust port provided in a cylinder is passed through the catalyst to the first expansion. And introduced into the chamber from the first expansion chamber through the opening formed in the partition panel to the second expansion chamber, and from the second expansion chamber to the outside through the outlet formed in the front outer wall panel. I will discharge Been, to the exhaust port peripheral portion of the cylinder, the front end of the front outer wall panel, the front end portion of the partition panel, and a flange portion provided at the front end of the diffuser, the first expansion chamber of bolts It is characterized by being fastened together.

The catalyst is preferably cylindrical or prismatic, and is inserted into the diffuser and fixed by spot welding.
The catalyst is preferably a metal carrier oxidation catalyst.

In another preferred embodiment, a spark arrester screen is attached to the opening formed in the partition panel.
In still another preferred aspect, a hook-like portion is provided at each of a rear end of the front outer wall panel, a rear end of the partition panel, and a front end of the rear outer wall panel, and the hook-like portions are sequentially stacked. And fastened together with bolts.

  Since the muffler with catalyst according to the present invention is configured to define an expansion chamber by a cup-shaped front outer wall panel and a rear outer wall panel that are separable from each other, the rear outer wall panel is used as the front outer wall panel. Before the mounting and defining the expansion chamber, the front outer wall panel is open, so that bolts for mounting and fixing can be inserted into the front outer wall panel and directly tightened to the cylinder. Therefore, the fixing bolts may be short, and the front outer wall panel, the partition panel, and the diffuser can be fastened together with the short bolts and simultaneously fixed to the cylinder. Therefore, the tightening and fixing position is near the cylinder as compared with the case where conventional long bolts are used, and the mounting stability, rigidity, and the like can be improved.

  In addition, the front outer wall panel, partition panel, and diffuser are fastened together with bolts, and the catalyst is fitted (press-fitted) into the diffuser and fixed by spot welding. Thus, time-consuming welding is reduced, and as a result, manufacturing costs can be reduced.

  Furthermore, since the exhaust gas purifying catalyst is preferably formed in a columnar shape or a prismatic shape and is fitted into the diffuser, the entire area of the catalyst is used for purifying the exhaust gas. Therefore, the purification ability of the catalyst can be utilized to the maximum, and the exhaust gas purification performance is greatly improved.

  In addition, an exhaust gas outlet is formed in the front outer wall panel, and separately from this, an opening is formed in the partition panel, and a spark arrester screen is attached to the opening. Design freedom can be increased.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic sectional view showing an embodiment of a muffler with a catalyst according to the present invention together with an internal combustion engine to which the muffler is applied.
In FIG. 1, an internal combustion engine 1 is a Schnure scavenging small air-cooled two-cycle gasoline engine incorporated as a power source for a portable work machine such as a brush cutter or a chain saw, similar to the conventional example shown in FIG. The displacement is about 23 to 45 mL, for example. The engine 1 includes a cylinder 2 having a hemispherical combustion chamber 5. The cylinder 2 is provided with a number of cooling fins 6 on its outer periphery, and has a circular or oval cross-sectional shape from the inner end side. An exhaust port 10 having a divergent shape (trumpet shape) whose cross-sectional area gradually increases toward the outer end side is provided, and further, although not illustrated, an intake port and a scavenging port are provided in a known manner. Yes.

  A muffler 20 of the present embodiment is attached to the outer side of the cylinder 2 on the exhaust port 10 side. The muffler 20 has an expansion chamber 25 defined by a cup-shaped front outer wall panel 21 and a rear outer wall panel 22 that are separable from each other. The expansion chamber 25 is disposed in the front outer wall panel 21. The cup-shaped partition panel 23 is partitioned into a first expansion chamber 25A and a second expansion chamber 25B.

  Near the center of the front end portion 21A of the front outer wall panel 21 located on the exhaust port 10 side, an opening 21a having substantially the same size and shape as the outer end portion of the exhaust port 10 is formed. Around this opening 21a, a diamond-shaped reinforcing plate 28 with a rounded angle in plan view in which an opening 28a having the same size and shape as the opening 21a is formed is fixedly attached by spot welding (see also FIG. 4).

  Further, a flange-shaped portion 21b having an L-shaped cross section is provided at the rear end of the front outer wall panel 21, and bolt insertion holes 21c are formed at the four corners of the flange-shaped portion 21b as shown in FIG. ing.

  A front end of the rear outer wall panel 22 is provided with a L-shaped flange-shaped portion 22b that is fitted inside the flange-shaped portion 21b of the front outer wall panel 21, and the four corners of the flange-shaped portion 22b are also provided. A bolt insertion hole 22c (see FIG. 7) is formed corresponding to the bolt insertion hole 21c of the front outer wall panel 21.

  A circular opening 23a is also formed near the center of the front end portion 23A of the partition panel 23, and at its rear end, as shown in FIG. 6, the hook-like portion 21b of the front outer wall panel 21 and the rear side A flange-like portion 23b sandwiched between the flange-like portion 22b of the outer wall panel 22 is provided, and the bolt insertion hole 21c of the front-side outer wall panel 21 and the rear-side outer wall panel are also provided at four corners of the flange-like portion 23b. Corresponding to the 22 bolt insertion holes 22 c, bolt insertion holes 23 c are formed.

  The front end portion 21A (the outer surface) of the front outer wall panel 21 is brought into contact with an overhang portion 2A in the cylinder 2 where the exhaust port 10 is open, and the front end portion 23A (of the partition panel 23) The outer surface) is brought into contact with the reinforcing plate 28, and the front end portion 23A (the inner surface) of the partition panel 23 has a rhombic hook-shaped portion 41 with rounded corners as seen in FIG. The flange-like portion 41 of the bottomed cylindrical diffuser 40 is brought into contact, and the periphery of the opening 23a of the partition panel front end portion 23A is sealed. In this case, the front outer wall panel 21 (reinforcing plate 28), the partition panel 23, and the diffuser 40 are arranged such that the center lines of the openings 21a, 28a, and 23a coincide with the center axis O of the diffuser 40. Be placed.

  The front end 21A of the front outer wall panel 21, the reinforcing plate 28, the front end 23A of the partition panel 23, and the flange 41 of the diffuser 40 are shown in FIGS. Thus, two bolt insertion holes 21d, 28d, 23d, and 41d are formed so as to overlap each other, and the bolt 26 is passed through these bolt insertion holes 21d, 28d, 23d, and 41d, and the cylinder 2 The front outer wall panel 21 (the reinforcing plate 28), the partition panel 23, and the diffuser 40 are directly fastened and fixed to the cylinder 2 by the bolts 26. .

  In addition, as shown in FIG. 7, the flange-shaped portion 21b of the front outer wall panel 21, the flange-shaped portion 23b of the partition panel 23, and the flange-shaped portion 22b of the rear outer wall panel 22 are sequentially stacked. The bolts 37 passed through the bolt insertion holes 21c, 23c, and 22c formed in the bolts 37 and the nuts 38 joined to the flanged portions 21b by welding are tightened together in a sealed state. It is fixed. Therefore, by loosening the tightening by the bolts 37, the rear outer wall panel 22 can be easily separated from the front outer wall panel 21, thereby facilitating maintenance and inspection.

  A cylindrical exhaust purification catalyst 30 is fitted (press-fitted) into the diffuser 40 on the front end portion 40A side and fixed by spot welding (spot weld portion 44), and the diffuser 40 has a periphery on the rear end portion 40B side. Exhaust gas outlet holes 43 are provided in the upper and lower portions on the surface portion. The catalyst 30 is a metal carrier oxidation catalyst having air permeability, and a cylindrical metal shell 32 is provided on the outer periphery thereof.

  Further, as shown in FIGS. 4 and 5, a louver-like outlet 29 is formed on one side of the rear end portion of the front outer wall panel 21. As shown in FIG. 1 and FIG. 6, a concave surface portion 23 </ b> D that is recessed inward is provided on the other side of the rear end portion (the side opposite to the outlet 29). A spark arrester screen 35 is attached by an appropriate attachment method such as spot welding so as to cover the opening 23e. Although not shown, an exhaust gas guide member for regulating the exhaust gas discharge direction is provided outside the outlet 29.

  Under such a configuration, the exhaust gas ejected from the exhaust port 10 at a speed close to the speed of sound is indicated by the solid line arrow in FIG. 1, and the opening 21 a and the reinforcing plate 28 of the front outer wall panel 21. It is guided into the diffuser 40 through the opening 28a and the opening 23a of the partition panel 23, and passes through the inside of the catalyst 30 fitted and fixed therein. At this time, the catalyst 30 reduces HC, CO, etc. in the exhaust gas. The exhaust gas that has passed through the catalyst 30 is blown into the first expansion chamber 25A through the exhaust gas outlet hole 43 of the diffuser 40 to be expanded and diffused, whereby the exhaust sound is attenuated. The exhaust gas expanded and diffused in the first expansion chamber 25 is led out to the second expansion chamber 25B through the spark arrester screen 35 attached to the partition panel 23, and the front outer wall is extended from the second expansion chamber 25B. It is discharged to the outside through the outlet 29 formed in the panel 21.

  The catalyst-equipped muffler 20 of this embodiment configured as described above is configured to define an expansion chamber 25 by a cup-shaped front outer wall panel 21 and a rear outer wall panel 22 that are separable from each other. Before the rear outer wall panel 22 is attached to the front outer wall panel 21 to define the expansion chamber, the front outer wall panel 21 is open, so that the bolts 26 for fixing the cylinder 2 can be easily attached. It can be inserted into the front outer wall panel 21 and tightened. Therefore, the mounting and fixing bolts 26 may be very short, and the front outer wall panel 21, the partition panel 23, and the diffuser 40 may be fastened together with the short bolts 26 and simultaneously fixed to the cylinder 2. it can. Therefore, the tightening and fixing position is closer to the cylinder 2 than when conventional long bolts are used, and the mounting stability, rigidity, and the like can be improved.

  In addition, the front outer wall panel 21, the partition panel 23, and the diffuser 40 are fastened and fixed together with bolts 26, and the catalyst 30 is fitted (press-fitted) into the diffuser 40 and fixed by spot welding. Compared to conventional ones, time-consuming work such as welding is reduced, and as a result, manufacturing costs can be greatly reduced.

  Furthermore, since the catalyst 30 has a columnar shape and is fitted into a bottomed cylindrical diffuser 40 that accepts all exhaust gas from the exhaust port 10 without leakage, the entire area of the catalyst 30 is exhaust gas. Used for purification. Therefore, the purification ability of the catalyst 30 can be utilized to the maximum, and the exhaust gas purification performance is greatly improved.

  In addition, an exhaust gas outlet 29 is formed on the front outer wall panel 21 and, separately from this, an opening 23e is formed in the partition panel 23, and a spark arrester screen 35 is attached to the opening 23e. The degree of freedom in designing the position and shape of the outlet 29 can be increased.

  As mentioned above, although one Embodiment of this invention was explained in full detail, this invention is not limited to the said embodiment, In design, without deviating from the mind of this invention described in the claim Various changes can be made.

  For example, in the above-described embodiment, the spark arrester screen 35 is attached to the recessed surface portion 23D of the partition panel 23, but the attachment position of the spark arrester screen 35 is not limited thereto, and is shown in FIG. 8, for example. Similarly, you may attach to the upper surface part 23B etc. of the partition panel 23. FIG.

  Further, in the embodiment, the exhaust gas outlet holes 43 are provided in the upper and lower peripheral surface portions on the rear end portion 40B side in the bottomed cylindrical diffuser 40. Instead, as shown in FIG. The hole 43 may be provided in the bottom surface portion 40 </ b> C of the diffuser 40.

  Furthermore, in order to prevent the surface of the outer wall panel 22 from becoming too hot, an inner wall panel 36 may be provided so as to form a heat insulating space 39 inside the outer wall panel 22 as shown in FIG. In this case, like the flanges 21b, 23b, and 22b of the front outer wall panel 21, the partition panel 23, and the rear outer wall panel 22, the flange 36b is provided at the front end of the inner wall panel 36. Is preferably fastened together so as to be sandwiched between the flange-shaped portion 23b of the partition panel 23 and the flange-shaped portion 22b of the rear outer wall panel 22.

  Further, the muffler with catalyst of the present invention can be similarly applied to a 4-cycle engine other than the air-cooled 2-cycle gasoline engine used in the embodiment.

  Further, as the exhaust gas purifying catalyst, it is possible to use a foamed molded body, a ceramic carrier, or the like other than those described above (metal carrier oxidation catalyst).

1 is a schematic cross-sectional view showing an embodiment of a muffler with a catalyst according to the present invention together with an internal combustion engine to which it is applied. The top view of a diffuser shown by FIG. Sectional drawing which expands and shows an exhaust-ports peripheral part and a diffuser part according to the III-III arrow line of FIG. The top view of the front side outer wall panel shown by FIG. FIG. 5 is a cross-sectional view taken along line VV in FIG. 4. The top view of the partition panel shown by FIG. The fragmentary sectional view which shows the state which fastened and fixed the outer wall panel and partition panel before and behind shown by FIG. The schematic sectional drawing which shows the modification of the muffler with a catalyst shown by FIG. The schematic sectional drawing which shows an example of the conventional muffler with a catalyst with the internal combustion engine to which it was applied. XX arrow line view of FIG.

Explanation of symbols

1 Internal combustion engine (small air-cooled 2-cycle gasoline engine)
2 Cylinder 10 Exhaust port 20 Muffler 21 Front outer wall panel 21A Front end portion 22 Rear outer wall panel 23 Partition panel 23A Front end portion 23e Opening 21b, 22b, 23b ... bowl-shaped portion 25 expansion chamber 25A first expansion chamber 25B second expansion chamber 26 Bolt 29 Outlet 30 Exhaust gas purification catalyst 35 Spark arrestor screen 37 Bolt 38 Nut 40 Diffuser 41 Flange

Claims (5)

  1. There is an expansion chamber (25) defined by a cup-shaped front outer wall panel (21) and a rear outer wall panel (22) that are separable from each other, and the expansion chamber (25) is the front outer wall panel (21). And the rear outer wall panel (22) are partitioned into a first expansion chamber (25A) and a second expansion chamber (25B) by a partition panel (23) arranged between the first expansion chamber (25A). ) Is provided with a bottomed cylindrical diffuser (40), and an exhaust gas purifying catalyst (30) having air permeability is fitted and fixed in the diffuser (40). The exhaust gas ejected from the exhaust port (10) is introduced into the first expansion chamber (25A) through the catalyst (30) and formed in the partition panel (23) from the first expansion chamber (25A). The second through the made opening (23e) It led to Choshitsu (25B), with catalyst muffler of an internal combustion engine that is adapted to discharge to the outside the second expansion chamber from (25B) through the outlet (29) formed in the front outer wall panel (21) Because
    At the periphery of the exhaust port (10) of the cylinder (2), the front end portion (21A) of the front outer wall panel (21), the front end portion (23A) of the partition panel (23), and the diffuser (40) A muffler with a catalyst for an internal combustion engine , wherein a flange portion (41) provided at the front end of the internal combustion engine is fastened together by bolts (26) in the first expansion chamber (25A) .
  2. 2. The muffler with a catalyst for an internal combustion engine according to claim 1 , wherein the catalyst (30) has a columnar shape or a prismatic shape, is fitted into the diffuser (40), and is fixed by spot welding. 3. .
  3. The muffler with a catalyst for an internal combustion engine according to claim 1 or 2 , wherein the catalyst (30) is a metal carrier oxidation catalyst.
  4. The catalyst for an internal combustion engine according to any one of claims 1 to 3 , wherein a spark arrester screen (35) is attached to the opening (23e) formed in the partition panel (23). Muffler with.
  5. At the rear end of the front outer wall panel (21), the rear end of the partition panel (23), and the front end of the rear outer wall panel (22), hook-shaped portions (21b, 23b, 22b) are provided, respectively. The hook-shaped portions (21b, 23b, 22b) are sequentially stacked and fixed together by bolts (37, 38), according to any one of claims 1 to 4 . Muffler with catalyst for internal combustion engine .
JP2004231133A 2004-08-06 2004-08-06 Muffler with catalyst for internal combustion engine Expired - Fee Related JP3955293B2 (en)

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DE200510037102 DE102005037102B4 (en) 2004-08-06 2005-08-03 Muffler mounted on a catalytic converter for an internal combustion engine
US11/197,905 US20060026953A1 (en) 2004-08-06 2005-08-05 Catalyst-attached muffler for internal combustion engine

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JP2006046264A (en) 2006-02-16
US20060026953A1 (en) 2006-02-09
DE102005037102A1 (en) 2006-02-23
DE102005037102B4 (en) 2012-11-29

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