Muffler for small engine

Abstract

A muffler for a small engine includes a first expansion chamber 12 for exhaust gas having an exhaust gas inlet 11 being connected to an exhaust gas outlet of the engine, a second expansion chamber 15 being partitioned from the first expansion chamber 12 by a partition plate 14 and being communicated with the first expansion chamber 12 through a first communicating hole 13 on the partition plate 14 , and a third expansion chamber 18 being partitioned from the second expansion chamber 15 by the partition plate 14 and being communicated with the second expansion chamber 15 through a second communicating hole 16 on the partition plate 14 and having an exhaust gas outlet 17 . A first heat resistant mesh catalyst 19 is disposed on the exhaust gas inlet 11 . A first exhaust gas purifier 20 composed of a heat resistant knit fabric 20 a coated with a catalyst for purifying the exhaust gas is disposed on the communicating hole 13 on the partition plate 14. Accordingly, the muffler for a small engine having a large muffling effect and a large purification effect on the exhaust gas can be provided. A manufacturing process of the exhaust gas purifier is simple and thereby a manufacturing cost of the muffler for a small engine is reduced.

1 . A muffler for a small engine, comprising:
 a first expansion chamber of exhaust gas having an exhaust gas inlet being connected to an exhaust gas outlet of the engine;   a second expansion chamber of the exhaust gas being partitioned from the first expansion chamber by a partition plate and being communicated with the first expansion chamber through a first communicating hole through the partition plate;   a third expansion chamber of the exhaust gas having an exhaust gas outlet and being partitioned from the second expansion chamber by the partition plate and being communicated with the second expansion chamber through a second communicating hole through the partition plate,
 a first heat resistant mesh catalyst disposed at the exhaust gas inlet; and 
 a first exhaust gas purifier composed of a knit fabric coated with a catalyst for purifying the exhaust gas and disposed at the first communicating hole. 
   
   
   
       2 . The muffler for a small engine according to  claim 1 , further comprising:
 a heat resistant cover having at least one exhaust gas inlet for supporting the knit fabric.   
   
   
       3 . The muffler for a small engine according to  claim 1 , further comprising:
 a second heat resistant mesh catalyst and a heat resistant cover having a plurality of exhaust gas outlets disposed on an outlet side of the exhaust gas; and   a third heat resistant mesh catalyst disposed replaceably on the exhaust gas outlet   wherein the first exhaust gas purifier is disposed on an exhaust gas inlet side of the first communicating hole through the partition plate.   
   
   
       4 . The muffler for a small engine according to  claim 1 , further comprising:
 a heat resistant cover made of a heat resistant mesh for supporting the knit fabric.   
   
   
       5 . The muffler for a small engine according to  claim 1 ,
 wherein at least an outer wall of the second expansion chamber which is not disposed on a side where the muffler is attached is constituted by a double-wall structure of walls.   
   
   
       6 . The muffler for a small engine according to  claim 1 ,
 wherein the outer wall of the second expansion chamber which is not at least the wall of the engine side is constituted by the double-wall structure of walls and a heat insulator is packed into a space between the double walls.   
   
   
       7 . The muffler for a small engine according to  claim 1 , further comprising:
 an exhaust gas receiver disposed inside the first expansion chamber disposed opposite the exhaust gas inlet, being connected to the exhaust gas inlet and having an exhaust gas outlet opposite the exhaust gas inlet; and   a second exhaust gas purifier composed of the heat resistant knit fabric coated with the catalyst for purifying the exhaust gas, being installed in a vicinity of the exhaust gas outlet inside the exhaust gas receiver; and   an inclined surface formed on the exhaust gas outlet so as to flow the exhaust gas in a direction toward the first exhaust gas purifier.   
   
   
       8 . The muffler for a small engine according to  claim 1 ,
 wherein the first heat resistant mesh catalyst is made of a SUS310S stainless steel mesh coated with the catalyst.   
   
   
       9 . The muffler for a small engine according to  claim 3 ,
 wherein the second heat resistant mesh catalyst is made of the SUS310S stainless steel mesh coated with the catalyst for purifying the exhaust gas,   the heat resistant cover is made of a SUS310S stainless steel sheet, and   the third heat resistant mesh catalyst is made of the SUS310S stainless steel mesh coated with the catalyst for purifying the exhaust gas.   
   
   
       10 . The muffler for a small engine according to  claim 7 ,
 wherein the exhaust gas receiver is made of the SUS310S stainless steel sheet.   
   
   
       11 . A muffler for a small engine, comprising:
 a first expansion chamber of the exhaust gas having an exhaust gas inlet being connected to an exhaust gas outlet of the engine;   a second expansion chamber being partitioned from the first expansion chamber by a partition plate;
 a third expansion chamber having an exhaust gas outlet being communicated with the second expansion chamber through a second communicating hole on the partition plate, 
 a first heat resistant mesh catalyst disposed at the exhaust gas inlet; 
 a convex part having at least one first communicating hole and protruding toward the first expansion chamber, the convex part made in an integrally molding manner with the partition plate; 
 a first exhaust gas purifier composed of a heat resistant knit fabric coated with the catalyst for purifying the exhaust gas installed on a concave part on the side of the second expansion chamber of the convex part; and 
 a heat resistant cover having an exhaust gas outlet disposed for covering the first exhaust gas purifier in a direction from the second expansion chamber. 
   
   
   
       12 . A muffler for a small engine, comprising:
 a first expansion chamber of the exhaust gas having an exhaust gas inlet being connected to an exhaust gas outlet of the engine;   a second expansion chamber which is partitioned from the first expansion chamber by a partition plate;
 a third expansion chamber having an exhaust gas outlet being communicated with the second expansion chamber through a second communicating hole on the partition plate; 
 a first heat resistant mesh catalyst disposed on the exhaust gas inlet; 
 a convex part having an exhaust gas outlet and protruding toward the second expansion chamber, the convex part made in an integrally molding manner with the partition plate; 
 a heat resistant knit fabric coated with a catalyst for purifying the exhaust gas installed on an exhaust gas inlet side on the side of the first expansion chamber of the convex part; and 
 a heat resistant cover having an exhaust gas outlet disposed for covering the first exhaust gas purifier the first expansion chamber. 
   
   
   
       13 . A muffler for a small engine, comprising:
 a first expansion chamber for the exhaust gas having an exhaust gas inlet being connected to an exhaust gas outlet of the engine;   a second expansion chamber being partitioned from the first expansion chamber by a partition plate having a communicating hole;   a first heat resistant mesh catalyst disposed on the exhaust gas inlet;   a first exhaust gas purifier composed of a heat resistant knit fabric coated with a catalyst for purifying the exhaust gas is disposed on the first communicating hole on the partition plate; and   an outside air suction pipe disposed through the second expansion chamber, a portion of the outside air suction pipe disposed opposite the first exhaust gas purifier and composed of a double pipe, an end of the outside air suction pipe bored through the outer wall and communicating with an outside air,   wherein a plurality of suction holes are bored through an outer pipe of the double pipe and the other end of the outside air suction pipe communicates with an exhaust gas outlet through an exhaust gas guide.   
   
   
       14 . The muffler for a small engine according to  claim 13 ,
 wherein the exhaust gas pipe is provided with a pipe having a check valve and being communicated with the first expansion chamber of the exhaust gas.   
   
   
       15 . A muffler for a small engine, comprising:
 a first expansion chamber of exhaust gas having an exhaust gas inlet being connected to an exhaust gas outlet of the engine;
 a second expansion chamber partitioned from the first expansion chamber by a partition plate having a communicating hole; 
 a first heat resistant mesh catalyst disposed on the exhaust gas inlet; 
 a first exhaust gas purifier composed of a heat resistant knit fabric coated with a catalyst for purifying the exhaust gas disposed on a first communicating hole on the partition plate; and 
 an exhaust gas pipe communicating the second expansion chamber with an exhaust gas outlet provided with a pipe being communicated with the first expansion chamber of the exhaust gas and having a check valve. 
   
   
   
       16 . The muffler for a small engine according to  claim 1 ,
 wherein a concave groove which is communicated with the third expansion chamber at an end and with the outside air at the other end is formed on an outer surface of the muffler, and   a groove cover covers the concave groove.   
   
   
       17 . The muffler for a small engine according to  claim 1 ,
 wherein an outside air suction pipe being opened at each end is fixed along the outer wall of the muffler so as to communicate with the exhaust gas outlet at an end and with the outside air at the other end.