Marine Exhaust System With Catalyst

Abstract

A marine engine exhaust system is provided that utilizes a single catalyst housing through which exhaust gases from multiple heads of an exhaust system flow. A first conduit directs a first exhaust gas from a first engine head or exhaust manifold to the catalyst, and a second conduit directs a second exhaust gas from a second engine head or exhaust manifold to the catalyst. The first and second conduits may be separate or may merge prior to the catalyst. The catalyst includes a housing and at least one substrate to convert the first and second exhaust gases into processed exhaust gas. A third conduit directs the processed exhaust gas away from the catalyst. At least one pre-sensor may be located upstream of the catalyst housing, and at least one post-sensor may be located downstream of the catalyst housing.

What is claimed is: 
     
         1 . A marine engine exhaust system, comprising:
 a first conduit in fluid communication with a first exhaust gas exiting from a first engine head;   a second conduit in fluid communication with a second exhaust gas exiting from a second engine head;   a catalyst in fluid communication with both said first and second exhaust gases having a housing and at least one substrate positioned within said housing in contacting engagement with said first and second exhaust gases to convert said first and second exhaust gases into at least one processed exhaust gas; and   a third conduit in fluid communication with said at least one processed exhaust gas exiting from said catalyst.   
     
     
         2 . The marine engine exhaust system as recited in  claim 1 , further comprising a first exhaust manifold interposed in fluid communication between said first engine head and said first conduit, and a second exhaust manifold interposed in fluid communication between said second engine head and said second conduit. 
     
     
         3 . The marine engine exhaust system as recited in  claim 1 , wherein said catalyst includes a first substrate in contacting engagement of said first exhaust gas to produce a first processed exhaust gas, and a second substrate in contacting engagement of said second exhaust gas to produce a second processed exhaust gas. 
     
     
         4 . The marine engine exhaust system as recited in  claim 3 , wherein each of said first and second conduits is in fluid communication with said catalyst housing. 
     
     
         5 . The marine engine exhaust system as recited in  claim 3 , wherein said third conduit is in fluid communication with said first processed gas exiting from said catalyst, and further comprising a fourth conduit in fluid communication with said second processed exhaust gas exiting from said catalyst. 
     
     
         6 . The marine engine exhaust system as recited in  claim 1 , wherein said first and second conduits join to form a merged conduit upstream of said catalyst, and wherein said merged conduit is in fluid communication between said first and second conduits and said catalyst housing. 
     
     
         7 . The marine engine exhaust system as recited in  claim 1 , wherein each of said first and second conduits are in fluid communication with said catalyst housing. 
     
     
         8 . The marine engine exhaust system as recited in  claim 1 , further comprising at least one pre-sensor in contacting engagement with said first and second exhaust gases. 
     
     
         9 . The marine engine exhaust system as recited in  claim 8 , wherein said catalyst includes said at least one pre-sensor. 
     
     
         10 . The marine engine exhaust system as recited in  claim 8 , wherein at least one of said first and second conduits includes said at least one pre-sensor. 
     
     
         11 . The marine engine exhaust system as recited in  claim 8 , wherein said first and second conduits join to form a merged conduit upstream of said catalyst, and wherein said merged conduit includes said at least one pre-sensor. 
     
     
         12 . The marine engine exhaust system as recited in  claim 1 , further comprising at least one post-sensor in contacting engagement with said at least one processed exhaust gas. 
     
     
         13 . The marine engine exhaust system as recited in  claim 12 , wherein said catalyst includes said at least one post-sensor. 
     
     
         14 . The marine engine exhaust system as recited in  claim 12 , wherein said third conduit includes said at least one post-sensor. 
     
     
         15 . The marine engine exhaust system as recited in  claim 1 , wherein said first and second engine heads are located on opposite sides of an engine. 
     
     
         16 . A marine engine exhaust system consisting essentially of:
 a first conduit in fluid communication with a first exhaust gas exiting from a first engine manifold;   a second conduit in fluid communication with a second exhaust gas exiting from a second engine manifold;   a catalyst in fluid communication with both said first and second exhaust gases having a housing and a substrate positioned within said housing in contacting engagement with said first and second exhaust gases to convert said first and second exhaust gases into processed exhaust gas;   a third conduit in fluid communication with said processed exhaust gas exiting from said catalyst;   a first pre-sensor in contacting engagement with said first exhaust gas located upstream of said substrate;   a second pre-sensor in contacting engagement with said second exhaust gas located upstream of said substrate; and   a post-sensor in contacting engagement with said processed exhaust gas located downstream of said substrate.   
     
     
         17 . The marine engine exhaust system as recited in  claim 16 , wherein said first and second conduits join to form a merged conduit upstream of said catalyst, and wherein said merged conduit is in fluid communication between said first and second conduits and said catalyst housing. 
     
     
         18 . The marine engine exhaust system as recited in  claim 17 , wherein said merged conduit includes a pre-sensor in contacting engagement with said first and second exhaust gases located upstream of said substrate.