Muffler

Abstract

A muffler ( 1 ) intended for portable working tools, preferably chain saws, in which the muffler is mounted directly to the exhaust gas outlet ( 3 ) of the cylinder ( 2 ). The muffler is provided with at least one upstream partition wall ( 4, 5 ) at the muffler's inlet ( 6 ) from the cylinder and arranged essentially laterally in relation to the engine's cylinder bore ( 7 ), so that the partition wall ( 4 ) separates an upper fraction ( 8 ) above it, i.e. in the direction towards the upper side of the cylinder, and a lower fraction below it, i.e. in the opposite direction, and this dividing into two or several fractions ( 8, 9, 10 ) is kept maintained through a great deal of the muffler from the inlet to a number of outlets ( 11, 12, 13 ).

1 . A muffler ( 1 ) intended for portable working tools, preferably chain saws, in which the muffler ( 1 ) is mounted directly to an exhaust gas outlet ( 3 ) of a cylinder ( 2 ), characterized in that the muffler is provided with at least one upstream partition wall ( 4 ,  5 ) at the muffler's inlet ( 6 ) from the cylinder, and arranged essentially laterally in relation to the engine's cylinder bore ( 7 ), so that the partition wall ( 4 ) separates an upper fraction ( 8 ) above it, i.e. in the direction towards the upper side of the cylinder, and a lower fraction ( 9 ) below it, i.e. in the opposite direction, and that this dividing into two or several fractions ( 8 ,  9 ,  10 ) is kept maintained through a great deal of the muffler from the inlet ( 6 ) to a number of outlets ( 11 ,  12 ,  13 ), so that the separated fractions ( 8 ,  9 ,  10 ), with different gas structure and different temperature can be treated separately essentially to avoid uncontrolled combustion of the exhaust gases under extremely high heat generation.  
     
     
         2 . A muffler ( 1 ) according to  claim 1 , characterized in that one or several upstream partition walls ( 4 ,  5 ) are drawn out into the exhaust gas outlet ( 3 ) of the cylinder and up to the cylinder bore ( 7 ), so that the dividing into fractions ( 8 ,  9 ,  10 ) will take place at an early stage.  
     
     
         3 . A muffler ( 1 ) according to  claim 1  or  2 , characterized in that at least one catalytic converter element ( 14 ) is arranged so that it comes into contact with one or several ( 8 , 9 ;  9 , 10 ) of the fractions ( 8 ,  9 ,  10 ).  
     
     
         4 . A muffler ( 1 ) according to  claim 3 , characterized in that the catalytic converter element ( 14 ) is arranged so that it comes into contact with one or several ( 8 , 9 ;  9 , 10 ) but not all the fractions ( 8 ,  9 ,  10 ).  
     
     
         5 . A muffler ( 1 ) according to any one of the preceding claims, characterized in that at least one upstream partition wall is at least partly variable in height, so that the amount of the fraction ( 8 ,  9 ,  10 ), above and below it, can be varied based on at least one engine parameter, such as flow speed, temperature, pressure or rotational speed.  
     
     
         6 . A muffler ( 1 ) according to any one of the preceding claims, characterized in that it is provided with at least one intermediate wall ( 21 ), which at least partly divides the muffler into a number of upstream volumes ( 15 ,  16 ) and a number of downstream volumes ( 17 ,  18 ), and separates the partition walls into upstream partition walls ( 4 ,  5 ) and downstream partition walls ( 19 ,  20 ).  
     
     
         7 . A muffler ( 1 ) according to any one of the preceding claims, characterized in that it is provided with a number of duct sections ( 22 ,  23 ), which connect to the inlet ( 6 ) of the muffler and have approximately the same width as this, so that each duct section within itself encloses preferably one fraction ( 8 ,  9 ,  10 ) and forwards this fraction with comparatively unreduced speed.  
     
     
         8 . A muffler ( 1 ) according to  claim 7 , characterized in that it has a subdivision into a number of sub duct sections of small cross sectional dimensions.  
     
     
         9 . A muffler ( 1 ) according to patent  claim 8  or  9 , characterized in that the duct sections ( 22 ,  23 ) are drawn so that they direct their exhaust gas flow towards at least one cooled surface, such as the muffler's front side ( 24 ), an upper side ( 25 ), a side surface ( 26 ,  27 ) or an intermediate wall ( 21 ), so that the exhaust gas flow of the duct section is cooled.  
     
     
         10 . A muffler ( 1 ) according to any one of the preceding claims, characterized in that it has at least one catalytic converter element ( 14 ) arranged in that at least one part of a partition wall ( 4 ,  5 ,  19 ,  20 ), or an intermediate wall ( 21 ), is coated with a catalytic layer ( 28 ) on one or both sides.  
     
     
         11 . A muffler ( 11 ) according to any one of the preceding claims, characterized in that it has at least one exhaust gas outlet ( 11 ,  12 ,  13 ) arranged in connection to its upper side ( 25 ).  
     
     
         12 . A muffler ( 1 ) according to  claim 11 , characterized in that it has at least one more exhaust gas outlet ( 11 ,  12 ,  13 ) arranged in connection to its front side ( 24 ).  
     
     
         13 . A muffler ( 1 ) according to any one of the preceding claims, characterized in that it has a protective cover ( 29 ) located above a large part of the upper side ( 25 ) of the muffler.  
     
     
         14 . A muffler ( 1 ) according to  claim 13 , characterized in that the protective cover ( 29 ) is curved around the corner between the upper side and the front side, so that it also covers a great deal of the front side ( 24 ) of the muffler.