Passive valve and resonator assembly for vehicle exhaust system

Abstract

An exhaust system includes first and second exhaust components with an inter-pipe that fluidly connects an outlet of the first exhaust component to an inlet of the second exhaust component. A passive valve is mounted within the inter-pipe. The second exhaust component defines an internal cavity that is at least partially packed with a high frequency absorption material and cooperates with the passive valve to effectively attenuate low and high frequency noise.

1 . A vehicle exhaust system comprising:
 a first exhaust component having a first inlet and a first outlet;   a second exhaust component positioned downstream of said first exhaust component, wherein said second exhaust component defines an internal cavity with a second inlet and a second outlet, said internal cavity being at least partially packed with a high frequency absorption material;   an inter-pipe connecting said first outlet with said second inlet; and   a passive valve mounted within said inter-pipe.   
     
     
         2 . The vehicle exhaust system according to  claim 1  wherein said inter-pipe comprises the sole exhaust gas flow path between said first outlet and said second inlet. 
     
     
         3 . The vehicle exhaust system according to  claim 1  wherein said first and said second exhaust components comprise first and second resonators. 
     
     
         4 . The vehicle exhaust system according to  claim 3  including a tailpipe in fluid communication with said second outlet. 
     
     
         5 . The vehicle exhaust system according to  claim 1  wherein said second inlet and said second outlet cooperate to define a flow path through said second exhaust component. 
     
     
         6 . The vehicle exhaust system according to  claim 5  wherein said flow path is defined by a pipe diameter and wherein said passive valve is mounted within the inter-pipe at a distance from said second inlet of said second exhaust component that is at least four times said pipe diameter. 
     
     
         7 . The vehicle exhaust system according to  claim 6  wherein said flow path comprises a sole flow path through said second exhaust component. 
     
     
         8 . The vehicle exhaust system according to  claim 7  wherein said sole flow path occupies a portion of said internal cavity of said second exhaust component leaving a remaining portion of said internal cavity, and wherein said remaining portion of said internal cavity is completely packed with said high frequency absorption material. 
     
     
         9 . The vehicle exhaust system according to  claim 1  wherein said passive valve comprises a vane supported on a shaft for pivotable movement within said inter-pipe between an open position and a closed position, and a spring that biases said vane toward said closed position, said vane being pivotal from said closed position towards said open position in response to an exhaust gas flow that exceeds a biasing force of said spring. 
     
     
         10 . The vehicle exhaust system according to  claim 1  including a pipe extending from said second inlet to said second outlet to define a sole flow path through said second exhaust component, said pipe including a perforated section positioned within said internal cavity, and wherein said high frequency absorption material is positioned to contact at least a portion of said perforated section to provide a packed second exhaust component. 
     
     
         11 . The vehicle exhaust system according to  claim 10  wherein said high frequency absorption material contacts an entire length of said perforated section to provide said packed second exhaust component. 
     
     
         12 . The vehicle exhaust system according to  claim 10  including at least one tuning tube positioned within said internal cavity and in communication with said pipe. 
     
     
         13 . A vehicle exhaust system comprising:
 a first exhaust component having a first inlet and a first outlet;   a second exhaust component defining an internal cavity having a second inlet and a second outlet that cooperate to define an internal flow path through said second exhaust component,;   a pipe extending from said second inlet to said second outlet to define said internal flow path as a sole flow path through said second exhaust component;   high frequency absorption material positioned within said internal cavity to contact at least a portion of said pipe to provide a packed second exhaust component;   an inter-pipe connecting said first outlet with said second inlet; and   a passive valve mounted within said inter-pipe.   
     
     
         14 . The vehicle exhaust system according to  claim 13  wherein said pipe occupies a portion of said internal cavity leaving a remaining portion, and wherein said remaining portion of said internal cavity is completely packed with a high frequency absorption material to provide said packed second exhaust component. 
     
     
         15 . The vehicle exhaust system according to  claim 14  wherein said first and said second exhaust components comprise first and second mufflers and wherein said inter-pipe comprises a sole exhaust gas flow path between said first outlet and said second inlet. 
     
     
         16 . The vehicle exhaust system according to  claim 13  wherein said pipe is defined by a pipe diameter and wherein said passive valve is mounted within said inter-pipe at a distance from said second inlet of said second exhaust component that is at least four times said pipe diameter. 
     
     
         17 . The vehicle exhaust system according to  claim 13  including a tailpipe fluidly connected to said second outlet of said second muffler. 
     
     
         18 . The vehicle exhaust system according to  claim 13  wherein said passive valve comprises a vane supported on a shaft for pivotable movement within said inter-pipe between an open position and a closed position, and a spring that biases said vane toward said closed position, said vane being pivotal from said closed position towards said open position in response to an exhaust gas flow that exceeds a biasing force of said spring. 
     
     
         19 . The vehicle exhaust system according to  claim 13  wherein said pipe includes a perforated section positioned within said internal cavity, and wherein said high frequency absorption material is positioned to contact at least a portion of said perforated section to provide said packed second exhaust component. 
     
     
         20 . The vehicle exhaust system according to  claim 19  wherein said high frequency absorption material contacts an entire length of said perforated section to provide said packed second exhaust component. 
     
     
         21 . The vehicle exhaust system according to  claim 13  wherein said first exhaust component comprises a first resonator and said packed second exhaust component comprises a packed second resonator, and wherein said inter-pipe comprises a sole exhaust gas flow path between said first outlet and said second inlet, said passive valve being mounted within said inter-pipe at a predetermined fixed distance from said second inlet of said packed second resonator. 
     
     
         22 . The vehicle exhaust system according to  claim 21  wherein said pipe of said packed second resonator is defined by a pipe diameter, and wherein said predetermined fixed distance is four times said pipe diameter. 
     
     
         23 . The vehicle exhaust system according to  claim 1  wherein said first exhaust component comprises a first resonator and said second exhaust component comprises a packed second resonator, and wherein said inter-pipe comprises a sole exhaust gas flow path between said first outlet and said second inlet, said passive valve being mounted within said inter-pipe at a predetermined fixed distance from said second inlet of said packed second resonator. 
     
     
         24 . The vehicle exhaust system according to  claim 23  including a pipe extending from said second inlet to said second outlet to define a sole internal flow path through said packed second resonator, said pipe being defined by a pipe diameter, and wherein said predetermined fixed distance is four times said pipe diameter.