Exhaust component with flexible membrane

Abstract

A vehicle exhaust system includes an exhaust component comprising a wall having an outer surface and an inner surface that defines an internal exhaust component cavity. At least one hole is formed in the exhaust component to extend through the wall of the exhaust component from the outer surface to the inner surface. A membrane is configured to overlap the at least one hole, wherein the membrane is moveable relative to the wall in response to pressure fluctuations.

what is claimed is: 
     
         1 . A vehicle exhaust system comprising:
 an exhaust component comprising a wall having an outer surface and an inner surface that defines an internal exhaust component cavity;   at least one hole formed in the exhaust component to extend through the wall of the exhaust component from the outer surface to the inner surface; and   a membrane configured to overlap the at least one hole, wherein the membrane is moveable relative to the wall in response to pressure fluctuations.   
     
     
         2 . The vehicle exhaust system according to  claim 1 , wherein the membrane is made from a flexible material. 
     
     
         3 . The vehicle exhaust system according to  claim 2 , wherein the flexible material can withstand temperatures within a range of 500-850 degrees Celsius. 
     
     
         4 . The vehicle exhaust system according to  claim 1 , wherein the wall comprises a rigid structure that has a first compliance and the membrane comprises a flexible structure that has a second compliance that is greater than the first compliance, and wherein the membrane elastically deforms in response to pressure changes within the internal exhaust component cavity. 
     
     
         5 . The vehicle exhaust system according to  claim 1 , wherein the membrane is impermeable. 
     
     
         6 . The vehicle exhaust system according to  claim 5 , wherein the wall is impermeable. 
     
     
         7 . The vehicle exhaust system according to  claim 1 , wherein the at least one hole is positioned at a pressure anti-node. 
     
     
         8 . The vehicle exhaust system according to  claim 1 , wherein the at least one hole comprises a plurality of holes that are each positioned at a pressure anti-node and which are each covered by a corresponding membrane. 
     
     
         9 . The vehicle exhaust system according to  claim 1 , wherein the exhaust component comprises a pipe having an overall pipe length extending from a first pipe end to a second pipe end, and wherein the at least one hole is positioned at a pressure anti-node location that is approximately 25%, 50%, or 75% of the overall pipe length. 
     
     
         10 . The vehicle exhaust system according to  claim 9 , wherein the at least one hole comprises a plurality of holes that are each positioned at one of the pressure anti-node locations. 
     
     
         11 . The vehicle exhaust system according to  claim 10 , wherein each hole is covered by a separate membrane. 
     
     
         12 . The vehicle exhaust system according to  claim 1 , wherein the membrane has both stiffness and damping and the pressure fluctuations cause the membrane to move and absorb energy from an oscillating wave resulting in lower downstream pressure oscillations. 
     
     
         13 . The vehicle exhaust system according to  claim 12 , wherein the stiffness and damping are adjusted such that a resonant frequency of the membrane is tuned to provide maximum suppression of the downstream pressure oscillations. 
     
     
         14 . The vehicle exhaust system according to  claim 1 , wherein the membrane is made from a flexible material that is impermeable and elastically deformable. 
     
     
         15 . The vehicle exhaust system according to  claim 14 , wherein the outer surface of the wall and the membrane are directly exposed to external atmosphere. 
     
     
         16 . A method comprising:
 providing an exhaust component comprising a wall having an outer surface and an inner surface that defines an internal exhaust component cavity;   forming at least one hole in the exhaust component to extend through the wall from the outer surface to the inner surface; and   positioning a membrane to overlap the at least one hole, wherein the membrane is moveable relative to the wall in response to pressure fluctuations.   
     
     
         17 . The method according to  claim 16 , including forming the membrane from a flexible material that is impermeable, elastically deformable, and can withstand temperatures within a range of 500-850 degrees Celsius. 
     
     
         18 . The method according to  claim 16 , wherein the wall comprises a rigid structure that has a first compliance and the membrane comprises a flexible structure that has a second compliance that is greater than the first compliance, and wherein the membrane elastically deforms in response to pressure changes within the internal exhaust component cavity. 
     
     
         19 . The method according to  claim 16 , including positioning the at least one hole at a pressure anti-node. 
     
     
         20 . The method according to  claim 16 , wherein the at least one hole comprises a plurality of holes, and including positioning each hole at a pressure anti-node, covering each hole with a separate membrane, and adjusting stiffness and damping of the membrane such that a resonant frequency of the membrane is tuned to provide maximum suppression of downstream pressure oscillations.