JPH08486Y2 - Exhaust muffler structure of internal combustion engine - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to an exhaust muffler structure for an internal combustion engine such as an air-cooled two-cycle gasoline engine used for small working machines such as brush cutters and chain saws.

[Conventional technology]

Conventionally, in a two-stroke gasoline engine of a small work machine as described above, exhaust gas is discharged from an exhaust port of a cylinder to an exhaust muffler, silenced, and discharged to the outside.

By the way, it is known to use an oxidation catalyst to reduce and purify HC (hydrocarbon), CO (carbon monoxide), etc. in the exhaust gas of an internal combustion engine such as a two-cycle gasoline engine. There is provided a cloth-like substrate on which a catalyst is attached (cross catalyst).

Therefore, it can be considered to provide the cross catalyst in the exhaust muffler to purify the exhaust gas as well as muffling.

However, in that case, since the strength of the cross catalyst is comparatively weak, when the cross catalyst is provided in the exhaust muffler, the flow velocity is high and the pulsating flow does not significantly impair the contact area with the exhaust gas power to improve the strength. It is necessary to support so that it can withstand, and since carbon and tar contained in the exhaust gas adhere to the cross catalyst, the cross catalyst can be easily attached and detached and cleaned easily as appropriate.
Although it is desired that the exhaust muffler can be replaced, an exhaust muffler structure satisfying these conditions has not been provided in the past.

[Problems to be solved by the device]

The present invention has been made in view of the above circumstances, and is capable of purifying exhaust gas by providing a cross catalyst inside thereof, and moreover, the cross catalyst does not significantly damage the contact area with the exhaust gas. It is intended to provide an exhaust muffler structure for an internal combustion engine that can be supported so as to withstand the forces in terms of strength, that the cross catalyst can be easily attached and detached, and its cleaning and replacement are easy, and that the structure is simple and inexpensive. is there.

[Means for solving the problem]

In order to solve the above-mentioned problems, the present invention comprises an exhaust muffler that can be divided and integrated, and an exhaust gas introduction cylinder and a pair of support pillars that are positioned substantially parallel to both sides thereof and through which muffler mounting bolts are inserted. A tubular member, which is disposed inside and has a cross catalyst sandwiched between holding nets, is laid over the pair of support columns so as to be deformed into a substantially elliptic tubular shape and enclose the exhaust gas introduction tube. It is configured.

[Action]

According to the present invention, the tubular member having the cross catalyst sandwiched between the holding nets is positioned substantially parallel to both sides of the exhaust gas introduction pipe so as to be deformed into a substantially elliptic cylinder and enclose the exhaust gas introduction pipe. Then, since the muffler mounting bolt is laid over a pair of support columns through which the exhaust muffler mounting bolt is inserted, the cross catalyst is eventually arranged so as to wrap around the exhaust gas introducing cylinder, and is introduced from the exhaust gas introducing cylinder. The exhaust gas thus generated passes through the cross catalyst and is purified.

Since the cross catalyst is sandwiched between the holding nets, it is reinforced by the holding net while taking a large contact area with the exhaust gas, and can sufficiently withstand the exhaust gas in terms of strength.

In addition, the tubular member is supported by a pair of support columns through which the muffler mounting bolt is inserted by a restoring force due to elastic deformation of the holding net. Therefore, the tubular member can be attached and detached very easily, and cleaning and replacement thereof can be facilitated. In other words, by attaching / detaching the cloth catalyst and cleaning / replacement it together with the tubular member, these can be performed very easily.

Further, since the tubular member is supported by the pair of support columns as described above, it is not necessary to provide a special fastening component or the like for attaching the tubular member, and the structure is simple and inexpensive.

Furthermore, the tubular member is formed, for example, by rolling a single wire mesh into a spiral shape, in which case a cross catalyst is sandwiched between the single mesh and the double mesh to form an overall cylindrical shape. It can be easily manufactured by joining the ends, and since the tubular member may be bridged between the pair of support columns as described above, the manufacturing is easy.

〔Example〕

An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing a state in which an exhaust muffler (B) according to an embodiment of the present invention is attached to a main body (A) of an air-cooled two-cycle gasoline engine, and FIG. 2 is II-II in FIG. Sectional view taken in the direction of the arrow, FIG. 3 shows the exhaust muffler (B).
FIG. 4 is an exploded perspective view of FIG. 4, and FIG. 4 is an enlarged view of the IV portion in FIG.

The engine body (A) is composed of a cylinder (1), a crank chamber (2), a piston (3), a crankshaft (4), a spark plug (5), etc. The device (32), an intake port (6) communicating with an air cleaner (not shown), and an exhaust port (7) to which the exhaust muffler (B) is connected are formed.

Further, in FIG. 1, (8) is a fuel tank, and (9)
Is an exhaust muffler cover. The exhaust muffler cover (9) is detachably fixed to the cylinder cover (10) side. Further, between the engine body (A) and the fuel tank (8) and the exhaust muffler (B), the heat of the exhaust muffler (B) is transferred to the engine body (A) and the fuel tank (8) side. A heat insulating plate (11) is provided as a guide for the cooling air as well as preventing it from being transmitted.

The exhaust muffler (B) according to the embodiment of the present invention is constructed as follows.

That is, the exhaust muffler (B) is in the form of a box that is press-formed from a thin steel plate as a whole, and has an inner exhaust muffler piece (12a) on the engine body (A) side and an exhaust muffler cover (9) side. Outer exhaust muffler piece (12b)
It is vertically divided into two parts, and can be divided and integrally sealed as described later.

An exhaust gas introducing cylinder (13) and a pair of support columns (14), (15) located substantially parallel to both sides of the exhaust gas introducing cylinder (13) are disposed inside.

The exhaust gas introducing cylinder (13) is fixed to an inner reinforcing plate (16) fixed to the inside of the inner exhaust muffler piece (12a) on the main body (A) side of the engine. The inner reinforcing plate (16) and the inner exhaust muffler piece (12a) have communication holes (17) communicating with the inside of the exhaust gas introducing cylinder (13),
(18) are provided respectively, and these communication holes (17),
The (18) communicates with the exhaust port (7). Further, a large number of small holes (19) are provided in the peripheral wall of the exhaust gas introducing cylinder (13) for internal and external communication.

Further, the support columns (14) and (15) are also fixed to the inner reinforcing plate (16). The support columns (14) and (15) are
Although it is for supporting a cylindrical member (27) described later,
In the case of the illustrated embodiment, both the exhaust muffler pieces (12a)
And (12b) are also configured to have a function of firmly integrating while preventing crushing. That is, each support pillar (1
4) and (15) are both exhaust muffler pieces (12a) and (12)
The outer reinforcing plate (20) whose right end in FIG. 1 is fixed to the inside of the outer exhaust muffler piece (12b) when the b) is integrated.
And a bolt insertion hole (21) and (22) are provided inside, respectively, to form a strong tubular shape. And both the reinforcing plates (16),
(20) and the exhaust muffler pieces (12a), (12b) are provided with insertion holes communicating with the bolt insertion holes (21), (22) of the support columns (14), (15), respectively. And
As shown in FIGS. 1 and 3, muffler mounting bolts (23), (24) projecting from both sides of the exhaust port (7) of the cylinder (1), specifically, a stud bolt (23). ，
(24) is the through holes of the inner exhaust muffler piece (12a), the through holes of the inner reinforcing plate (16), the bolt through holes (21), (22) of the support columns (14), (15), Stud bolts (21), (22) protruding outward from the outer exhaust muffler piece (12b) by being inserted through the respective through holes of the outer reinforcing plate (20) and the respective through holes of the outer exhaust muffler piece (12b). Both exhaust muffler pieces (12a) and (12b) can be integrally sealed by screwing nuts (25) and (26) at the tip of the nuts (25) and (26), respectively.
The exhaust muffler pieces (12a) and (12
b) can be divided.

However, it is not necessary to configure the support pillars (14) and (15) so as to divide and integrate the exhaust muffler pieces (12a) and (12b) as in the embodiment shown in the drawings. For example, both exhaust muffler pieces (12a) and (1
2b) A latch (not shown) is provided at one end and a hinge (not shown) is provided at the other end, thereby dividing and integrating both exhaust muffler pieces (12a) and (12b). Can be free.

Further, in the figure, (27) is a substantially cylindrical tubular member, and the substantially cylindrical member (27) is a holding net (2
The cross catalyst (29) is sandwiched between 8). That is, in the case of the embodiment shown in the drawings, one wire mesh (2
8) is wound into a spiral shape, and the cross catalyst (29) is sandwiched between the single and double meshes to make the whole into a substantially cylindrical shape. As shown in FIG. ) Is joined to the overlapping portion (31). Although the overlapping portion (31) is joined by spot welding, it may be joined by other means such as a fastener.

As the holding net (28), for example, a stainless wire net can be used, and the wire diameter, mesh, etc. can be appropriately selected. Further, the cross catalyst (29) is
A cloth-like substrate with an oxidation catalyst attached, for example,
Product called PANACROS Pure manufactured by Matsushita Electric Industrial Co., Ltd. (A thin carrier layer made of silica or alumina is formed on the surface of ceramic cloth, and a small amount of platinum, palladium, etc. is supported as a catalyst metal on the carrier layer with high dispersion. I made it)
Can be used.

In addition, in the case of the embodiment shown in the drawings, as described above, one wire mesh (28) is spirally doubly rounded, and the cross catalyst (29) is sandwiched between the first and double meshes. , A single wire mesh (28) is rolled into triple, quadruple, etc., and the cross catalyst (29) is sandwiched between the double and triple eyes as well as between the single and double eyes. But it is good. In this way, by increasing the number of turns, it is possible to easily increase the contact area between the exhaust gas and the catalyst without increasing the capacity of the entire muffler, and to improve the oxidation efficiency by the catalyst, that is, the exhaust gas purification efficiency. Is advantageous.

The tubular member (27) may have a structure in which a cross catalyst is sandwiched between two metal nets, and these are rounded to join the overlapping portions at the ends. Also in this case, not only the one in which the cloth catalyst is sandwiched between the two metal nets is not rounded,
The number of turns such as double and triple may be increased.

Then, the tubular member (27) is deformed into a substantially elliptic tubular shape, and as shown in FIGS. 1 and 2, the pair of support columns (so as to enclose the exhaust gas introduction tube (13) ( 14),
(15) It is bridged between. The tubular member (2
The movement of 7) in the axial direction (the left-right direction in FIG. 1) is prevented by contacting the reinforcing plates (16) and (20).

 In FIG. 1, (30) is a discharge pipe.

According to the exhaust muffler (B) of the present invention having the above structure, the exhaust gas generated by the operation of the engine is introduced from the exhaust port (7) of the cylinder (1) of the engine into the exhaust muffler (B). It is discharged into the cylinder (13).
Then, the exhaust gas passes through the small holes (1
9), and the cross catalyst (2) of the tubular member (27).
After passing through 9) for noise reduction and purification, it is finally discharged from the exhaust pipe (30) to the outside.

Since the cross catalyst (29) is sandwiched between the holding nets (28), it is reinforced by the holding nets (28) without significantly impairing the contact area with the exhaust gas.
The strength of exhaust gas can be sufficiently endured.

Further, the tubular member (27) is supported by the pair of support columns (14), (15) through which the muffler mounting bolt is inserted by the restoring force due to the elastic deformation of the holding net (28). . Therefore, the tubular member (27) can be attached and detached very easily, and the cleaning and replacement thereof can be facilitated. That is,
Attaching and detaching and replacing the cross catalyst (29) is performed by the tubular member (27).
These can be done very easily by doing each step.

Further, since the tubular member (27) is supported by the pair of support columns (14) and (15) as described above, the tubular member (2)
There is no need to provide any special tightening parts to attach 7), and the structure is simple and inexpensive.

Furthermore, the tubular member (27) has, for example, a single holding net (28) rolled into a spiral shape, in which case the cross catalyst (29) is sandwiched between the single mesh and the double mesh, and Can be manufactured by joining the ends of the holding net (28) to each other, and the substantially cylindrical member (27) can be formed into a pair of support columns (14), (15) as described above. It is easy to manufacture because it can be laid over.

[Effect of device]

According to the present invention, a cross catalyst can be provided inside to effectively purify the exhaust gas, and the strength of the cross catalyst can be improved without significantly damaging the contact area of the cross catalyst with the exhaust gas. The cloth catalyst can be supported so that it can withstand it sufficiently, the cross catalyst can be easily attached and detached, its cleaning and replacement can be easily performed, and further, the structure is simple and the cost is low.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a vertical sectional view showing a state in which an exhaust muffler is attached to an engine body,
2 is a sectional view taken along the line II-II in FIG. 1, FIG. 3 is an exploded perspective view of the exhaust muffler, and FIG. 4 is an enlarged view of an IV portion in FIG. (13) …… Exhaust gas introducing cylinder, (14), (15) …… Supporting pillar, (27) …… Cylindrical member, (28) …… Holding net, (29)…
… Cross catalyst.

Claims (1)

[Scope of utility model registration request] 1. An exhaust muffler (B) is constructed so that it can be divided and integrated, and the muffler mounting bolts (23), (24) are located substantially parallel to the exhaust gas introducing cylinder (13) and both sides thereof.
A cylindrical member (27) having a pair of support columns (14) and (15) through which the cross catalyst (29) is inserted and a crossing catalyst (29) sandwiched between holding nets (28) is a substantially elliptic cylinder. An exhaust muffler structure for an internal combustion engine, characterized in that the exhaust muffler is laid over the pair of support columns (14) and (15) so as to surround the exhaust gas introduction cylinder (13).