Combination Liquid-Cooled Exhaust Manifold Assembly And Catalytic Converter Assembly For A Marine Engine

Abstract

An exhaust system for a marine engine comprising liquid cooled manifold and catalytic converter assemblies. Each assembly uses a separate cooling system to cool either the exhaust manifold or a shell inside which resides the catalytic converter. The housing or shell containing the catalytic converter uses water to cool an exterior surface of a water jacket to an acceptable temperature conforming to federal regulations. The liquid-cooled manifold assembly may use either water or glycol to cool a jacket surrounding tubes extending from the engine block to the catalytic converter assembly.

1 . An exhaust system for a marine engine, comprising:
 a combination of a liquid-cooled exhaust manifold assembly and a liquid-cooled catalytic converter assembly, which liquid-cooled exhaust manifold assembly comprises a manifold jacket surrounding tubular exhaust runners extending from cylinders of the marine engine to the catalytic converter assembly, liquid being supplied to and from the manifold jacket to cool the outside surface of the manifold jacket to maintain the outside temperature of the manifold jacket below a predetermined temperature, and liquid being supplied to and from a fluid passage surrounding a catalytic converter housing to cool and maintain the outside surface of the catalytic converter assembly below a predetermined temperature.   
   
   
       2 . The system of  claim 1  wherein said manifold jacket is made of sheet metal. 
   
   
       3 . The system of  claim 1  wherein said manifold jacket is shaped like a clam shell. 
   
   
       4 . The system of  claim 1  wherein said manifold jacket is made from multiple pieces welded together. 
   
   
       5 . The system of  claim 1  wherein each of the tubular exhaust runners is approximately the same length. 
   
   
       6 . The system of  claim 1  wherein the liquid being supplied to and from the housing to cool the outside surface of the manifold is water. 
   
   
       7 . The system of  claim 1  wherein the liquid being supplied to and from the housing to cool the outside surface of the manifold is glycol. 
   
   
       8 . An exhaust system for a marine engine, comprising:
 a liquid-cooled catalytic converter assembly including a catalytic converter fixed inside an inner shell and an outer shell surrounding the inner shell, the inner and outer shells defining a fluid passage therebetween, the outer shell being joined to the inner shell proximate an inlet end of the catalytic converter assembly, wherein the outer shell has a fluid inlet in fluid communication with the fluid passage to introduce fluid into the fluid passage to cool and maintain the outside surface of the catalytic converter assembly below a predetermined temperature when liquid passes through the fluid passage; and   a liquid-cooled exhaust manifold assembly comprising a plurality of tube stubs welded to a mounting plate, a baffle, and a plurality of tubular exhaust runners welded to the baffle and the mounting plate and extending therebetween, said exhaust manifold assembly further comprising a manifold jacket surrounding the tubular exhaust runners and being welded to the baffle and the tube stubs, said manifold jacket having an inlet for introducing fluid inside said manifold jacket and an outlet for removing fluid from the manifold jacket to cool the outside surface of the manifold jacket to maintain the outside temperature of the manifold jacket below a predetermined temperature.   
   
   
       9 . The system of  claim 8  wherein said manifold jacket is made from sheet metal. 
   
   
       10 . The system of  claim 9  wherein said manifold jacket is shaped like a clam shell. 
   
   
       11 . The system of  claim 8  wherein said manifold jacket is made from multiple parts. 
   
   
       12 . The system of  claim 8  wherein said catalytic converter assembly has bosses adapted to receive oxygen sensors. 
   
   
       13 . The system of  claim 8  wherein said exhaust manifold assembly has four tubular exhaust runners. 
   
   
       14 . The system of  claim 8  wherein said tubular exhaust runners of said exhaust manifold assembly are welded to stubs welded to said mounting plate of said exhaust manifold assembly. 
   
   
       15 . An exhaust system for a marine engine, comprising:
 a liquid-cooled catalytic converter assembly including a catalytic converter, an inner shell and an outer shell surrounding the inner shell, the inner and outer shells defining a fluid passageway therebetween, wherein the outer shell has a fluid inlet in fluid communication with the fluid passage to introduce fluid into the fluid passage to cool and maintain the outside surface of the catalytic converter assembly below a predetermined temperature when liquid passes through the fluid passage; and   a liquid-cooled exhaust manifold assembly comprising a mounting plate for securing the exhaust system to the marine engine, a plurality of tube stubs welded to the mounting plate, a baffle, and a plurality of exhaust runners, each of said exhaust runners being welded to the mounting plate at one end and to the baffle at the other end, said baffle being welded to the catalytic converter assembly, said manifold assembly further comprising a manifold jacket comprising upper and lower half shells welded together and surrounding the exhaust runners, said manifold jacket having an inlet for introducing fluid inside a fluid cavity defined by said manifold jacket, said baffle and said tube stubs and an outlet for removing fluid from the manifold jacket to cool the outside surface of the manifold jacket to maintain the outside temperature of the manifold jacket below a predetermined temperature.   
   
   
       16 . The system of  claim 15  wherein said manifold jacket is made from multiple pieces of sheet metal. 
   
   
       17 . The system of  claim 15  wherein said catalytic converter assembly has bosses adapted to receive oxygen sensors. 
   
   
       18 . The system of  claim 15  wherein said exhaust manifold assembly has four tubular exhaust runners. 
   
   
       19 . The system of  claim 15  wherein said exhaust runners of said exhaust manifold assembly are tubular. 
   
   
       20 . The system of  claim 15  wherein each of the exhaust runners is approximately the same length.