Muffler assembly with sound absorbing member

Abstract

A muffler is disclosed that includes a housing, an inlet pipe, an outlet pipe, a first partition with first apertures, and a second partition with second apertures. The first partition and housing define a first chamber with which the inlet pipe communicates. The second partition and housing define a second chamber with which the outlet pipe communicates. The second partition is spaced from the first partition to define an intermediate chamber. The muffler also includes a sound absorbing member encapsulated within the intermediate chamber. Exhaust noise entering through the inlet pipe enters the first chamber, moves through the first apertures into the intermediate chamber, moves through the second apertures into the second chamber, and exits through the outlet pipe. Exhaust noise is reduced when passing through the sound absorbing member.

1 . A vehicular exhaust system muffler comprising: 
 a housing having an input wall and an output wall;    first and second apertured partitions inside the housing defining an input chamber with one of the input and output walls, defining an output chamber with another one of the input and output walls, and an intermediate chamber defined between the first and second partitions;    a sound absorbing member positioned in the intermediate chamber;    an inlet pipe entering the housing through the input wall and terminating in the input chamber; and    an outlet pipe having an end positioned in the output chamber and another end exiting the housing through the output wall.    
     
     
         2 . The muffler of  claim 1  wherein the input chamber is adjacent the output wall and the inlet pipe extends from the input wall through the output chamber and the intermediate chamber before terminating in the input chamber, the inlet pipe further including apertures therein enabling fluid communication between the inlet pipe and the intermediate chamber.  
     
     
         3 . The muffler of  claim 2  wherein the output chamber is adjacent the input wall and the outlet pipe extends from the output chamber through the intermediate and input chambers to the output wall, the outlet pipe further including apertures therein enabling fluid communication between the intermediate chamber and the outlet pipe.  
     
     
         4 . The muffler of  claim 1  further comprising a flow-through pipe extending from the input chamber through the intermediate chamber to the output chamber and having a valve at one end thereof operative to vary an open area of the one end as a function of exhaust flow pressure.  
     
     
         5 . The muffler of  claim 1  wherein the sound absorbing member comprises roving material.  
     
     
         6 . The muffler of  claim 5  wherein the roving material comprises strands of fiberglass fibers.  
     
     
         7 . The muffler of  claim 5  wherein the roving material comprises strands of basalt wool.  
     
     
         8 . The muffler of  claim 1  further comprising a third solid partition defining with the housing a supplemental sound absorbing chamber containing a supplemental sound absorbing member, and wherein the outlet pipe extends through the supplemental sound absorbing chamber and the intermediate chamber, the outlet pipe having perforations enabling fluid communication between the outlet pipe and the supplemental sound absorbing chamber.  
     
     
         9 . The muffler of  claim 8  wherein the sound absorbing member comprises a roving material having a first density and the supplemental sound absorbing member comprises a roving material having a second density.  
     
     
         10 . The muffler of  claim 9  wherein the first density is less than the second density.  
     
     
         11 . The muffler of  claim 1  wherein the input chamber is adjacent the input wall and the inlet pipe extends through the input wall and terminates in the input chamber.  
     
     
         12 . The muffler of  claim 11  wherein the output chamber is adjacent the output wall.  
     
     
         13 . The muffler of  claim 12  further comprising a flow-through pipe extending from the input chamber to the output chamber and having a valve at one end thereof operative to vary an open area of the one end as a function of exhaust pressure.