Concentricity spacer for a catalyst device of a marine engine

Abstract

The exhaust system for a marine engine provides a concentricity spacer located between an outer surface of a generally tubular member of a catalyst device and an inner surface of a generally tubular cavity formed within a catalyst housing structure. The concentricity spacer is shaped to allow fluid to pass through the spacer in a direction generally parallel to a central axis of the tubular member.

1 . An exhaust system for a marine engine, comprising:
 a first catalyst device comprising a first catalyst material disposed within a first generally tubular member;   a catalyst housing structure having a first generally tubular cavity formed therein, said first tubular cavity being shaped to receive said first tubular member therein, said first tubular cavity and said first tubular member being sized to define a first space disposed between an outer surface of said first generally tubular member and an inner surface of said first generally tubular cavity; and   a first concentricity spacer disposed between an outer surface of said first generally tubular member and an inner surface of said first generally tubular cavity, said first concentricity spacer being configured to maintain a generally uniform thickness of said first space between said outer surface of said first generally tubular member and an inner surface of said first generally tubular cavity, said first concentricity spacer maintaining concentricity of said first generally tubular member as a cantilever in said first space.   
     
     
         2 . The exhaust system of  claim 1 , further comprising:
 a second catalyst device comprising a second catalyst material disposed within a second generally tubular member;   said catalyst housing structure having a second generally tubular cavity formed therein, said second tubular cavity being shaped to receive said second tubular member therein, said second tubular cavity and said second tubular member being sized to define a second space disposed between an outer surface of said second generally tubular member and an inner surface of said second generally tubular cavity; and   a second concentricity spacer disposed between an outer surface of said second generally tubular member and an inner surface of said second generally tubular cavity, said second concentricity spacer being configured to maintain a generally uniform thickness of said second space between said outer surface of said second generally tubular member and an inner surface of said second generally tubular cavity.   
     
     
         3 . The exhaust system of  claim 2 , wherein:
 said first and second catalyst devices are disposed in serial fluid communication with a plurality of exhaust ports which are configured to direct a flow of exhaust gas from a plurality of cylinders of said marine engine.   
     
     
         4 . The exhaust system of  claim 4 , wherein:
 said first and second catalyst devices are disposed in parallel fluid communication with each other.   
     
     
         5 . The exhaust system of  claim 2 , wherein:
 said first and second concentricity spacers each comprise a plurality of raised ribs shaped to define the thickness of said space.   
     
     
         6 . An exhaust system for a marine engine, comprising:
 a plurality of catalyst devices, each of said catalyst devices comprising a catalyst material disposed within a generally tubular member;   a catalyst housing structure having a plurality of generally tubular cavities formed therein, each of said plurality of generally tubular cavities being shaped to receive an associated one of said generally tubular members therein, each of said generally tubular cavities and each of said generally tubular members being sized to define a space disposed between an inner surface of said first generally tubular cavity and an outer surface of said associated generally tubular member; and   a plurality of alignment spacers, each of said plurality of alignment spacers being disposed within said space of an associated one of said generally tubular cavities, each of said alignment spacers maintaining concentricity of a respective said generally tubular member as a cantilever in a respective said space.   
     
     
         7 . The exhaust system of  claim 6 , wherein:
 each of said plurality of catalyst devices is disposed in a common plane.   
     
     
         8 . The exhaust system of  claim 6 , wherein:
 said plurality of catalyst devices is disposed in serial fluid communication with a plurality of exhaust ports which are configured to direct a flow of exhaust gas from a plurality of cylinders of said marine engine.   
     
     
         9 . The exhaust system of  claim 7 , wherein:
 each one said plurality of catalyst devices is disposed in parallel fluid communication with each other one of said plurality of catalyst devices.   
     
     
         10 . The exhaust system of  claim 8 , further comprising:
 an exhaust conduit attached to said catalyst housing structure.   
     
     
         11 . The exhaust system of  claim 9 , wherein:
 said catalyst housing structure is disposed between said plurality of exhaust ports and said exhaust conduit.   
     
     
         12 . The exhaust system of  claim 6 , wherein:
 said alignment spacer comprises a plurality of raised ribs shaped to define the thickness of said space.   
     
     
         13 . An exhaust system for a marine engine, comprising:
 a plurality of catalyst devices, each of said catalyst devices comprising a catalyst material disposed within a generally tubular member, each of said plurality of catalyst devices being disposed in a common plane;   a catalyst housing structure having a plurality of generally tubular cavities formed therein, each of said plurality of generally tubular cavities being shaped to receive an associated one of said generally tubular members therein, each of said generally tubular cavities and each of said generally tubular members being sized to define a space disposed between an inner surface of said first generally tubular cavity and an outer surface of said associated generally tabular member, each of said plurality of catalyst devices being disposed in a common plane; and   a plurality of alignment spacers, each of said plurality of alignment spacers being disposed within said space of an associated one of said plurality of generally tubular cavities each of said alignment spacers maintaining concentricity of a respective said generally tubular member as a cantilever in a respective said space.   
     
     
         14 . The exhaust system of  claim 13 , wherein:
 each one said plurality of catalyst devices is disposed in parallel fluid communication with each other one of said plurality of catalyst devices.   
     
     
         15 . The exhaust system of  claim 13 , further comprising:
 an exhaust conduit attached to said catalyst housing structure.   
     
     
         16 . The exhaust system of  claim 14 , wherein:
 said catalyst housing structure is disposed between said plurality of exhaust ports and said exhaust conduit.   
     
     
         17 . The exhaust system of  claim 13 , wherein:
 said plurality of catalyst devices is disposed in serial fluid communication with a plurality of exhaust ports which are configured to direct a flow of exhaust gas from a plurality of cylinders of said marine engine.   
     
     
         18 . The exhaust system of  claim 13 , wherein:
 each of said plurality of alignment spacers comprises a plurality of raised ribs shaped to define the thickness of said space.