JPH11148336A - Muffler with spark arrester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent carbon from sticking to the spark arrester mounted in a muffler even when an engine driven mower is used for a long time. SOLUTION: A hot tube 4 with exhaust inlet 4a and exhaust outlet 4b is secured in a muffler 3, and a spark arrester 5 made of a net covering the exhaust outlet 4b is detachably secured in the hot tube 4, and a catalyst 6 made of platinum and rhodium is coated with the hot tube 4. When an engine 1 is started, the hot tube 4 is heated to a high temperature by the exhaust heat of engine, as a result, the carbon stuck on the spark arrester 5 is burned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a muffler with a spark arrestor mounted on an engine-driven mower or the like, and more particularly, to a muffler with a spark arrestor which is hardly clogged even when used for a long time.

[0002]

2. Description of the Related Art Engine driven mowers and brush cutters are
Often used in forests, fields and grasslands. Therefore, in order to prevent the sparks discharged from the muffler of the engine from igniting hay such as forests, a spark arrestor having a mesh size standard is installed in the muffler to prevent the sparks from diffusing from the muffler.

[0003]

By the way, it is overwhelmingly likely that a small and lightweight two-stroke engine is mounted on an engine-driven mower or the like. Due to the internal structure of the two-stroke engine, the fuel and the engine lubricating oil are mixed with air and vaporized to explode and burn in the engine engine. Therefore, compared to the four-stroke engine, the amount of carbon emitted from the engine is large. As a result, carbon tends to adhere to the spark arrester installed inside the muffler, and as the usage time of a mower or the like becomes longer, the spark arrester becomes clogged, reducing the exhaust efficiency and reducing the engine's original performance. Not only can not be exhibited, but also the work efficiency is reduced and the work time is prolonged. Also, if the spark arrestor, whose performance has deteriorated due to clogging, has to be cleaned and replaced, the trouble, time and cost of removing the muffler from the engine body, disassembling the muffler and collecting the spark arrestor, etc. will increase. There was such a problem.

An object of the present invention is to provide a muffler with a spark arrestor which is less likely to be clogged irrespective of the use period, in view of the above-mentioned problems in the conventional muffler with a spark arrester.

[0005]

In order to achieve this object, according to the first aspect of the present invention, a bolt is fastened to and detachable from a cylinder block 2 of an engine 1 mounted on an engine-driven mower or the like. In the muffler with the spark arrestor described above, a hot tube 4 having an exhaust inlet 4a on the front surface and an exhaust outlet 4b on the other surface is mounted inside the muffler 3, so that the exhaust from the engine 1 is supplied to the exhaust inlet 4a.
From the exhaust pipe 4b, and after being discharged from the exhaust outlet 4b, is discharged into the muffler 3. Further, the spark arrestor 5 of a mesh covering the exhaust outlet 4b is attached to and detached from the hot tube 4. Attach as possible,
The present invention is characterized in that the entire surface of the jacket of the hot tube 4 is coated with a catalyst 6 made of platinum and rhodium.

According to a second aspect of the present invention, the alloy ratio of the catalyst 6 is approximately platinum: rhodium = 5: 1 to 10: 1.
It is characterized by being.

[0007]

According to the first aspect of the present invention, the cylinder block 2 of the engine 1 mounted on an engine-driven mower or the like is provided.
In a muffler with a spark arrestor which is bolted and detachable, a spark arrestor 5 is mounted inside, a catalyst 6 made of platinum and rhodium is coated, and an exhaust inlet 4a and an exhaust outlet 4b are connected. When the engine 1 is started and rotated in a state where the hot tube 4 is installed in the muffler 3, the temperature of the hot tube 4 gradually starts rising due to heat exhausted from the engine, and is considerably longer than the hot tube not coated with the catalyst 6. It gets hot. The hot tube 4, which has become hot, also exposes the attached spark arrester 5 of the mesh body to a high temperature and burns the carbon adhering to the spark arrester 5. As a result, the carbon attached to the spark arrester 5 is burned out, so that the spark arrester 5 is less likely to be clogged. Therefore, even if the spark arrester 5 is used for a long time, it is possible to prevent the engine performance from being deteriorated due to the deterioration of the exhaust efficiency, and it is possible to set a longer cleaning time or replacement time of the spark arrester 5.

According to the second aspect of the present invention, the alloy ratio of the catalyst 6 is substantially platinum: rhodium = 5: 1 to 10: 1.
By doing so, the temperature of the hot tube 4 in the muffler 3 is further increased, and the carbon adhering to the spark arrester 5 is easily burned. Therefore, even if an engine-driven mower or the like is used for a long time, carbon is less likely to adhere to the spark arrester 5, and the labor, time, and cost for disassembling the muffler 3 and cleaning or replacing the spark arrester 5 can be omitted. .

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to 4, reference numeral 1 denotes an engine, and a cylinder block 2 is provided above the engine 1.
Is installed. The wall of the muffler 3 is in contact with the opening edge of the exhaust port 21 of the cylinder block 2 via a gasket 22 and a heat shield plate 23, and a guide plate 31 having an exhaust hole is provided inside the wall of the muffler 3. Are located. Further, inside the muffler 3, a wall 32 whose entire periphery is caulked by the outer peripheral edge of the muffler 3 is provided, and an exhaust pipe 33 is inserted obliquely. At a substantially central portion of the wall portion 32, a convex hot tube engaging portion 34 provided with a muffler fixing bolt hole (not shown) is provided. The internal shape of the muffler 3 is such that the hot tube 4 can be incorporated therein, and the muffler 3 incorporating the hot tube 4 is bolted to the cylinder block 2 by muffler fixing bolts 7 together. .

The hot tube 4 is formed by vertically extending a back plate 44 having a bolt hole 43 through which a muffler fixing bolt 7 is inserted at a rear end surface of a downwardly U-shaped member comprising an upper plate 41 and left and right side plates 42, 42. The muffler 3 is attached to the hot tube engaging portion 34 so as to engage with the hot tube engaging portion 34, and the open front surface is defined as the exhaust inlet 4a. Then, the left and right guide plate portions 45a having a shape for enclosing the shaft portion of the muffler fixing bolt 7,
Lower plate 45 having an exhaust outlet 4b on its lower surface.
The upper surface of the lower plate 45 is slightly spaced from the lower end surfaces of the left and right side plates 42 so that the spark arrestor 5 can be closely inserted in the longitudinal direction while being attached horizontally to the vertical surface of the back plate 44. To be arranged. Then, a spark arrester 5 (for example, constituted by a stainless steel net) is detachably inserted in the gap in the horizontal direction. Furthermore, the above hot tube 4
Is coated with a catalyst 6 having an alloy ratio of platinum to rhodium of approximately 5: 1 to 10: 1. Further, since the catalyst 6 is expensive, a part of the hot tube 4 may be coated, or another catalyst such as palladium may be mixed. Further, the exhaust outlet 4b may be opened on a surface other than the exhaust inlet 4d, which is the front surface of the hot tube 4.

The back plate 4 of the hot tube 4 having the above structure.
The side of the muffler 3 is engaged with the hot tube engaging portion 34 in the muffler 3 and is incorporated into the muffler 3, and the muffler fixing bolt is inserted through a muffler fixing bolt hole (not shown) of the muffler 3 and a bolt hole 43 of the hot tube 4. The bolt 7 is bolted to the cylinder block 2 of the engine 1. The exhaust gas discharged from the engine 1 is supplied to the exhaust inlet 4a.
Flows into the hot tube 4 from the spark arrester 5
And is exhausted into the muffler 3 from the exhaust outlet 4b, and then discharged through the exhaust pipe 33 to the outside of the muffler 3. In addition, the code | symbol 11 in a figure has shown the engine cover.

Next, the operation when an operator uses an engine-driven mower or the like will be described. When an operator starts and rotates the engine 1 to use an engine-driven mower or the like, the exhaust from the engine 1 passes through the exhaust port 21 of the cylinder block 2 and the hot tube 4 mounted in the muffler 3. The gas flows into the hot tube 4 from the exhaust gas inlet 4a. The exhaust gas that has flowed into the hot tube 4 is discharged out of the hot tube 4 from the exhaust outlet 4b covered by the net spark arrester 5 while gradually heating the entire hot tube 4 by the exhaust heat. Then, the exhaust gas discharged from the hot tube 4 flows into the exhaust pipe 33 and is discharged outside the muffler 3. After a certain period of time in such a state, the temperature inside the hot tube 4 becomes high.

According to the experimental results at the time of steady engine rotation, the temperature of the hot tube not coated with the catalyst 6 rises only up to about 500 ° C., whereas the temperature of the hot tube 4 coated with the catalyst 6 is about 1000 ° C. The result was that the temperature rose to C.

The hot tube 4, which has become hot, also exposes the spark arrestor 5 of the mesh body mounted inside to a high temperature, so that carbon adhering to the spark arrester 5 can be burned. As a result, the carbon attached to the spark arrester 5 is burned out, so that the spark arrester 5 is less likely to be clogged. Therefore, even if the mower or the like is used for a long time, the spark arrester 5 is unlikely to be clogged, so that the exhaust efficiency is prevented from being deteriorated. When the catalyst 6 is coated on the spark arrester 5, the temperature of the spark arrester 5 can be further increased efficiently.

[0015]

According to the first aspect of the present invention, there is provided a muffler with a spark arrestor, which is bolted to a cylinder block of an engine mounted on an engine-driven mower or the like, and which is detachable, the spark arrester is provided. Since the hot tube mounted inside was incorporated in the muffler and the hot tube was coated with at least a catalyst made of platinum and rhodium, the engine was started and rotated to use an engine-driven mower or the like. Thus, the temperature of the hot tube gradually starts to rise, and eventually becomes higher than that of the hot tube not coated with the catalyst as in the prior art. The hot tube, which has become hot, exposes the spark arrestor of the mesh attached inside to a high temperature, and can burn carbon adhering to the spark arrester. As a result, the carbon attached to the spark arrester is burned out, so that the spark arrester is less likely to be clogged. Therefore, even if an engine-driven mower or the like is used for a long time, it is possible to prevent a decrease in engine performance due to deterioration of exhaust efficiency, and it is possible to set a longer cleaning time or replacement time of the spark arrester. .

According to the second aspect of the present invention, the alloy ratio of the catalyst is substantially platinum: rhodium = 5: 1 to 10: 1.
By doing so, the temperature of the hot tube in the muffler can be further increased, and the carbon adhering to the spark arrester can be easily burned. Therefore, even if an engine-driven mower or the like is used for a long period of time, carbon is less likely to adhere to the spark arrester, and the labor, time, and cost for disassembling the muffler to clean or replace the spark arrester can be reduced.

[Brief description of the drawings]

FIG. 1 is a partially cutaway sectional view showing a configuration of a muffler with a spark arrestor of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a bottom view illustrating the configuration of the hot tube in FIG. 1;

FIG. 4 is a schematic perspective view illustrating a configuration of a hot tube and a spark arrester of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Cylinder block 3 Muffler 4 Hot tube 4a Exhaust inflow port 4b Exhaust outflow port 5 Spark arrestor 6 Catalyst 7 Muffler fixing bolt

Claims (2)

[Claims] 1. A muffler with a spark arrestor, which is bolted to a cylinder block (2) of an engine (1) mounted on an engine-driven mower or the like and is detachable, has an exhaust inlet on a front surface. (4a) and the exhaust outlet (4b) on the other side
A hot tube (4) having the following structure is mounted inside the muffler (3), and exhaust from the engine (1) is supplied to the exhaust inlet (4).
a) flows into the hot tube (4), is discharged from the exhaust outlet (4b), and is then discharged to the inside of the muffler (3). Further, the mesh covers the exhaust outlet (4b). The spark arrester (5) is detachably attached to the hot tube (4), and the hot tube (4)
A catalyst comprising at least platinum and rhodium (6)
A muffler with a spark arrestor characterized by being coated with 2. The muffler with a spark arrestor according to claim 1, wherein the alloy ratio of the catalyst (6) is substantially platinum: rhodium = 5: 1 to 10: 1.