Silencer and exhaust gas system comprising a silencer

Abstract

A silencer is provided that is intended to be connected to a gas flow with pressure fluctuations, such as for example downstream a combustion engine, the silencer comprising a housing provided with an envelope surface and two side surfaces and an inlet opening and an outlet opening arranged in the envelope surface.

1 . Silencer intended to be connected to a gas flow with pressure fluctuations such as for example downstream a combustion engine, the silencer comprising a housing ( 4 ) provided with an inlet opening ( 9 ) and an outlet opening ( 10 ), a partition wall ( 1   b ) and a turning chamber ( 7 ,  8 ) where the flow is carried from one side of the partition wall ( 1   b ) to the other whereby the partition wall ( 1   b ) divides the flow in two substantially opposite directed flow paths on both sides of the partition wall ( 1   b ), characterized in that the partition wall ( 1   b ) is formed from a band ( 1   a ) which is folded to Z shape to a package which forms a set of inlet channels ( 21 ) on one side of the partition wall ( 1   b ) and a set of outlet channels ( 22 ) on the other side of the partition wall ( 1   b ).  
     
     
         2 . Silencer according to  claim 1 , characterized in that the partition wall ( 1   b ) is non-rigidly formed, whereby pressure fluctuations on both sides of the partition wall are reduced.  
     
     
         3 . Silencer according to  claim 2 , characterized in that the thickness of the partition wall ( 1   b ) is less than 0,2 mm, preferably less than 0,1 mm.  
     
     
         4 . Silencer according to any of claims  1 - 3 , characterized in that each of the sets of inlet channels ( 21 ) and outlet channels ( 22 ) comprises an upper and a lower substantially plane surface ( 24 - 25 ,  27 - 28 ) and that the substantially plane surfaces ( 24 - 25 ,  27 - 28 ) are formed with a set of protrusions which are provided to generate a large number of irregular flow ways through each of the substantially opposite directed flow paths.  
     
     
         5 . Silencer according to  claim 4 , characterized in that the protrusions have such an extension length from the upper and lower plane surfaces ( 24 - 25 ,  27 - 28 ) comprised in the channels ( 21 ,  22 ) that it is not possible to look from one end to the opposite end of the channels ( 21 ,  22 ).  
     
     
         6 . Silencer according to any of claims  1 - 5 , characterized in that each of the sets of inlet channels ( 21 ) and outlet channels ( 22 ) is defined by an upper and a lower substantially plane surface ( 24 - 25 ,  27 - 28 ) and a fold ( 26 ,  29 ) connecting the surfaces and that the upper and the lower substantially plane surfaces ( 24 - 25 ,  27 - 28 ) are substantially parallel.  
     
     
         7 . Silencer according to any of the preceding claims, characterized in that the partition wall ( 1   b ) forms at least 10 inlet and outlet channels ( 21 ,  22 ) positioned on top of each other.  
     
     
         8 . Silencer according to any of the preceeding claims, where the package is provided with a set of inner fold edges ( 26 ) where the band is folded counterclockwise and a set of outer fold edges ( 29 ) where the band is folded clockwise, characterized in that the extension length from an inner fold edge ( 26 ) to an outer fold edge ( 29 ) of the inlet and outlet channels ( 21 ,  22 ) substantially exceeds the height from an upper channel wall to a lower channel wall.  
     
     
         9 . Silencer according to  claim 8 , characterized in that the relation between the height from an upper channel wall to a lower channel wall and the extension length from an inner fold edge ( 26 ) and an outer fold edge ( 29 ) is between {fraction (1/30)} and {fraction (1/100)}.  
     
     
         10 . Silencer according to any of the preceeding claims, the silencer comprises a housing ( 4 ) provided with an envelope surface ( 30 ) and two side surfaces ( 31 ,  32 ), where the inlet opening ( 9 ) and the outlet opening ( 10 ) are arranged in the envelope surface ( 30 ), characterized in that first a and a second turning chamber ( 7 ,  8 ) are arranged in connection with the side surfaces ( 31 ,  32 ), and that the partition wall ( 1   b ) extends between the respective turning chamber ( 7 ,  8 ), whereby the set of inlet channels ( 21 ) leads from the inlet opening ( 9 ) to the turning chamber and the set of outlet channels ( 22 ) leads from the turning chamber to the outlet opening ( 10 ), whereby the partition wall ( 1   b ) divides the flow in two substantially opposite directed flow paths from the inlet opening ( 9 ) via turning chambers and which flow paths meet at the outlet opening ( 10 ).  
     
     
         11 . Silencer according to  claim 10 , characterized in that the relation between the extension length from turning chamber ( 7 ) to turning chamber ( 8 ) and the extension length from an inner fold edge ( 26 ) to an outer fold edge ( 27 ) is between 1,1 and 6, preferably between 1,4 and 3.  
     
     
         12 . Silencer according to any of claims  10  or  11 , characterized in that the inlet opening ( 9 ) and the outlet opening ( 10 ) are symmetrically positioned with respect to the partition wall ( 1   b ), whereby the flow path from the inlet opening ( 9 ) to the outlet opening ( 10 ) is the same independent of through which turning chamber ( 7 ,  8 ) the flow passes.  
     
     
         13 . Silencer according to  claim 12 , characterized in that the inlet opening ( 9 ) and the outlet opening ( 10 ) are positioned midway between the edge regions of the partition wall ( 1   b ) that are connected to the turning chamber ( 7 ,  8 ).  
     
     
         14 . Silencer according to any of the preceeding claims, characterized in that the partition wall ( 1   b ) is provided with perforations.  
     
     
         15 . Use of a silencer according to any of the preceeding claims in a exhaust gas system for a combustion engine downstream a first catalyst.