Exhaust silencer

Abstract

An exhaust silencer includes a flow pipe supported in a housing. A space is defined between the flow pipe and the housing. At least one movable flap is located in the space and is resiliently biased to a closed position and movable by exhaust gas pressure from said closed position to an opened position. The at least one flap provides less restriction to exhaust gas flow through the space in the opened position as compared to the closed position. The one or more flaps are pivotably supported on a spring-biased hinge assembly or are provided as part of a resiliently deformable baffle plate that uncovers flow apertures under force of exhaust pressure. The baffle plate is selectively removable by an end-user to allow for maximum exhaust flow when desired. The flow pipe can be omitted in a base plate only version.

1 . An exhaust silencer comprising: 
 a housing;    a flow pipe supported in said housing;    a space defined between said flow pipe and said housing;    at least one movable flap located in said space and resiliently biased to a closed position and movable by exhaust gas pressure from said closed position to an opened position, wherein said at least one flap provides less restriction to exhaust gas flow through said space in said opened position as compared to said closed position.    
   
   
       2 . The exhaust silencer as set forth in  claim 1 , wherein said at least one flap pivots between said closed and opened positions.  
   
   
       3 . The exhaust silencer as set forth in  claim 2 , wherein said at least one flap comprises first and second separate flaps that each pivot between said closed and opened positions.  
   
   
       4 . The exhaust silencer as set forth in  claim 3 , further comprising at least one spring engaged with said first and second flaps to bias said first and second flaps to their respective closed positions.  
   
   
       5 . The exhaust silencer as set forth in  claim 4 , further comprising first and second hinges that extend between said flow pipe and said housing, wherein said first and second flaps are each connected to both said first and second hinges, and wherein said at least one spring is a torsion spring connected to one of said first and second hinges.  
   
   
       6 . The exhaust silencer as set forth in  claim 5 , wherein said at least one spring comprises first and second springs respectively connected to said first and second hinges, wherein each of said first and second springs is engaged with both of said first and second flaps.  
   
   
       7 . The exhaust silencer as set forth in  claim 6 , further comprising first and second stops located between said housing and said flow pipe, said first and second stops abutting said first and second flaps, respectively, when said first and second flaps are in their respective closed positions.  
   
   
       8 . The exhaust silencer as set forth in  claim 7 , wherein said first and second flaps define a 180 degree angle therebetween when the first and second flaps moved to their closed positions, and wherein said first and second flaps define therebetween an angle of less than 180 degrees when the first and second flaps are moved their respective opened positions.  
   
   
       9 . The exhaust silencer as set forth in  claim 7 , wherein said flow pipe is located centrally in said housing so that said space defined between said housing and said flow pipe is an annular space that encircles said flow pipe.  
   
   
       10 . The exhaust silencer as set forth in  claim 9 , wherein said first and second hinges are arranged in diametrically opposed locations relative to each other.  
   
   
       11 . The exhaust silencer as set forth in  claim 10 , wherein said flow pipe defines an unobstructed flow path from an open upstream end to an open downstream end thereof.  
   
   
       12 . The exhaust silencer as set forth in  claim 1 , wherein said at least one flap is defined as part of a flexible metal baffle that is secured in said space, wherein said at least one flap moves from said closed position to said opened position by resilient deformation of said metal baffle under force of exhaust gas pressure in said space, and wherein said at least one flap resiliently moves from said opened position to said closed position when said exhaust gas pressure in said space subsides.  
   
   
       13 . The exhaust silencer as set forth in  claim 12 , wherein said at least one flap comprises first and second flaps.  
   
   
       14 . The exhaust silencer as set forth in  claim 13 , wherein said first and second flaps are defined by said metal baffle as a one-piece construction.  
   
   
       15 . The exhaust silencer as set forth in  claim 12 , further comprising a base plate secured in said space between said flow pipe and said housing, said base plate defining at least one flow aperture, wherein said metal baffle is secured to said base plate and occludes said at least one flow aperture when in said closed position and moves away from said at least one flow aperture when in said opened position.  
   
   
       16 . The exhaust silencer as set forth in  claim 15 , wherein said metal baffle is secured to said base plate by at least one removable fastener that allow for selective separation of said baffle from said base plate for maximum exhaust flow.  
   
   
       17 . The exhaust silencer as set forth in  claim 16 , wherein said base plate comprises an outer flange that is secured to said housing and comprises a pipe support aperture through which said flow pipe extends, and wherein said baffle comprises an opening through which said flow pipe extends.  
   
   
       18 . The exhaust silencer as set forth in  claim 12 , wherein said metal baffle comprises a flexible metal sheet.  
   
   
       19 . The exhaust silencer as set forth in  claim 1 , wherein said at least one flap is defined by a stack of at least two flexible metal baffles that are secured in said space, wherein said at least one flap moves from said closed position to said opened position by resilient deformation of said stack of metal baffles under force of exhaust gas pressure in said space, and wherein said at least one flap resiliently moves from said opened position to said closed position by relative flattening of said stack of metal baffles when said exhaust gas pressure in said space subsides.  
   
   
       20 . The exhaust silencer as set forth in  claim 20 , further comprising a base plate secured in said space between said flow pipe and said housing, said base plate defining at least one flow aperture, wherein said stack of metal baffles is secured to said base plate and occludes said at least one flow aperture when in said closed position and moves away from said at least one flow aperture when in said opened position.  
   
   
       21 . An exhaust silencer comprising: 
 a housing;    a base plate secured in the housing, the base plate comprising at least one main flow opening and at least one secondary flow opening;    at least one flexible metal baffle secured to the base plate and normally resiliently biased to a closed position where it covers the secondary flow aperture, wherein said baffle is resiliently movable by exhaust gas pressure from said closed position to an opened position where it moves away from the at least one secondary flow opening to allow exhaust gas flow through the at least one secondary flow opening.