Method of using syntactic foam to reduce noise and machine using same

Abstract

A method of decreasing engine noise in machines, such as internal combustion engines, by replacing metallic engine components that serve as noise transmission pathways such as oil pans, valve covers, gear covers with similar components made of syntactic foam with a density of at least 0.5 g/cm 3 and a hardness at least about equal to that of an equivalent metallic engine part which it is replacing. The syntactic foam is comprised of fluid-filled microballoons in a foam matrix. The microballoons have an outer shell harder than that of the surrounding foam matrix, and a majority of the microballoons are out of contact with one another.

1 . A machine comprising:
 a plurality of machine components being attached to one another, and at least one of the components being comprised of syntactic foam;   the syntactic foam including a polymer matrix and a plurality of fluid-filled microballoons, a density of 0.5 g/cm 3  or greater, and a hardness of at least about Shore D 74; and   a majority of the microballoons being out of contact with one another, and each microballoon including fluid surrounded by a shell more rigid than the matrix, and the fluid being a majority of a volume of each microballoon.   
   
   
       2 . The machine of  claim 1  wherein the machine being an engine, and the at least one component includes a valve cover. 
   
   
       3 . The machine of  claim 1  wherein the at least one component includes a gear cover. 
   
   
       4 . The machine of  claim 1  wherein the at least one component includes an oil pan. 
   
   
       5 . An engine comprising:
 a plurality of engine components being attached to one another and including a portion being metallic components and a portion being comprised of a syntactic foam component.   
   
   
       6 . The engine of  claim 5  wherein the syntactic foam component includes a valve cover. 
   
   
       7 . The engine of  claim 5  wherein the syntactic foam component includes a gear cover. 
   
   
       8 . The engine of  claim 5  wherein the syntactic foam component includes an oil pan. 
   
   
       9 . The engine of  claim 5  wherein the syntactic foam includes a density of 0.5 g/cm 3  or greater. 
   
   
       10 . The engine of  claim 5  wherein the syntactic foam includes a hardness of at least about Shore D 74. 
   
   
       11 . The engine of  claim 5  wherein the syntactic foam includes a polymer matrix and a plurality of fluid-filled microballoons, and a majority of the microballoons being out of contact with one another. 
   
   
       12 . The engine of  claim 5  wherein the syntactic foam includes a polymer matrix and a plurality of fluid-filled microballoons, and each microballoon includes a fluid surrounded by a shell more rigid than the matrix and the fluid being a majority of a volume of each microballoon. 
   
   
       13 . The engine of  claim 12  wherein the syntactic foam components include at least one of a valve cover, a gear cover, and an oil pan; and
 the syntactic foam includes a density of 0.5 g/cm 3  or greater, a hardness of at least about Shore D 74, and a majority of the microballoons being out of contact with one another.   
   
   
       14 . A method of reducing sound emitted from a machine comprising a step of:
 substituting a syntactic foam machine component for a metallic machine component.   
   
   
       15 . The method of  claim 14  wherein the machine being an engine, and the machine component including at least one of a valve cover, a gear cover, and an oil pan. 
   
   
       16 . The method of  claim 14  wherein the syntactic foam component includes a polymer matrix and a plurality of fluid-filled microballoons, a density of 0.5 g/cm 3  or greater, and a hardness of at least about Shore D 74; and
 a majority of the microballoons being out of contact with one another, and each microballoon including fluid surrounded by a shell more rigid than the matrix, and the fluid being a majority of a volume of each microballoon.