Catalyst-attached muffler for internal combustion engine

Abstract

A catalyst-installed muffler includes an expansion chamber ( 25 ), and a gas-permeable exhaust gas-purifying catalyst ( 30 ), wherein exhaust gas blown out of the exhaust port ( 10 ) of an internal combustion engine is introduced into the expansion chamber ( 25 ) through the catalyst ( 30 ). The catalyst ( 30 ) may be cylindrical in configuration. An outer circumferential cross-sectional configuration of the catalyst ( 30 ) is made identical with an inner circumferential cross-sectional configuration of the outer end portion ( 10 a ) of the exhaust port ( 10 ), so that one end portion (exhaust gas introducing side 30 a ) of the catalyst ( 30 ) is enabled to fit in an outer end portion ( 10 a ) of the exhaust port ( 10 ). According to this muffler, it is made possible to utilize the purifying capacity of the catalyst to a maximum extent.

1 . A muffler capable of cooperating with an exhaust port of an internal combustion engine, the muffler comprising: 
 an expansion chamber, and    a gas-permeable exhaust gas-purifying catalyst capable of allowing exhaust gas from the exhaust port to flow through the catalyst and be introduced into the expansion chamber,    wherein one end portion of the catalyst is positioned in an outer end portion of the exhaust port.    
     
     
         2 . The muffler of  claim 1  wherein the catalyst is cylindrical or prismatic in configuration, and an outer circumferential cross-sectional configuration of the catalyst is substantially identical with an inner circumferential cross-sectional configuration of the outer end portion of the exhaust port.  
     
     
         3 . The muffler of  claim 1  wherein the catalyst is an oxidation catalyst formed of a metallic carrier.  
     
     
         4 . The muffler of  claim 2  wherein the catalyst is an oxidation catalyst formed of a metallic carrier.  
     
     
         5 . The muffler of  claim 1  wherein the exhaust port is tapered in configuration and the cross-sectional area thereof gradually increases from an inner end to the outer end thereof.  
     
     
         6 . The muffler of  claim 4  wherein the exhaust port is tapered in configuration and the cross-sectional area thereof gradually increases from an inner end to the outer end thereof.  
     
     
         7 . The muffler of  claim 1  wherein the engine is a small air-cooled two-stroke gasoline engine.  
     
     
         8 . The muffler of  claim 6  wherein the engine is a small air-cooled two-stroke gasoline engine.  
     
     
         9 . A muffler capable of cooperating with an exhaust port of an internal combustion engine, the muffler comprising: 
 an expansion chamber, and    a gas-permeable exhaust gas-purifying catalyst capable of allowing exhaust gas from the exhaust port to flow through the catalyst and be introduced into the expansion chamber,    wherein the catalyst is cylindrical or prismatic in configuration, and an outer circumferential cross-sectional configuration of the catalyst is substantially identical with an inner circumferential cross-sectional configuration of an outer end portion of the exhaust port.    
     
     
         10 . The muffler of  claim 9  wherein the catalyst is an oxidation catalyst formed of a metallic carrier.  
     
     
         11 . The muffler of  claim 9  wherein the exhaust port is tapered in configuration and the cross-sectional area thereof gradually increases from an inner end to the outer end thereof.  
     
     
         12 . The muffler of  claim 10  wherein the exhaust port is tapered in configuration and the cross-sectional area thereof gradually increases from an inner end to the outer end thereof.  
     
     
         13 . The muffler of  claim 9  wherein the engine is a small air-cooled two-stroke gasoline engine.  
     
     
         14 . The muffler of  claim 12  wherein the engine is a small air-cooled two-stroke gasoline engine.