Marine Engine Exhaust Silencing System

Abstract

A silencing system for a marine exhaust system incorporates a single muffler for each engine of the marine vessel. The muffler is provided with two sound dampening chambers interconnected by several exhaust openings between the chambers. A Y-shaped exhaust type system directs exhaust streams from both sides of an engine toward a single exhaust conduit which extends through a transom of the marine vessel. The muffler is provided with a drain opening that allows water to flow out of the first chamber of the muffler in order to maximize the available volume within that chamber for use in sound attenuation. The outlet of the second chamber is provided with a baffle plate that directs the flow of exhaust gas in a forward direction toward the transom of the marine vessel and a deflection surface that directs the exhaust gas to flow in a downward direction toward the surface of the body of water in which the marine vessel is operated.

1 . A marine engine exhaust silencing system, comprising:
 an engine disposed within a marine vessel;   an exhaust conduit connected in fluid communication with a plurality of exhaust ports of said engine and extending through a transom of said marine vessel;   a muffler attached to a rear surface of said transom, said muffler having first and second chambers configured to direct exhaust gas from said exhaust conduit through said first chamber and into said second chamber, said second chamber having an outlet which is configured to direct said exhaust gas away from said muffler in a direction which is both downward toward a surface of a body of water in which said marine vessel is operating and forward toward said transom;   wherein:   said outlet comprises a plate which is configured to cause said exhaust gas to turn toward a generally forward direction toward said transom;   said outlet further comprises a surface which is configured to deflect said exhaust gas received from said plate from a primarily forward direction toward said transom toward a downward direction toward said surface of said body of water in which said marine vessel is operating.   
   
   
       2 . The silencing system of  claim 1 , wherein:
 said plurality of exhaust ports of said engine comprises a first plurality of exhaust ports on a first side of said engine and a second plurality of exhaust ports on a second side of said engine, said first plurality of exhaust ports being connected to said exhaust conduit by a first exhaust pipe, said second plurality of exhaust ports being connected to said exhaust conduit by a second exhaust pipe.   
   
   
       3 - 4 . (canceled) 
   
   
       5 . The silencing system of  claim 1 , further comprising:
 an auxiliary exhaust passage connected in fluid communication with said exhaust conduit;   an auxiliary muffler having an inlet connected in fluid communication with said auxiliary exhaust passage and an outlet extending through said transom; and   a shroud attached to said rear surface of said transom and configured to direct a portion of said exhaust gas, which passes through said auxiliary muffler, in a generally downward direction toward said surface of said body of water in which said marine vessel is operating.   
   
   
       6 . The silencing system of  claim 1 , further comprising:
 a drain opening formed in said muffler and configured to permit water to flow out of said muffler.   
   
   
       7 . The silencing system of  claim 6 , wherein:
 said drain opening is formed in a surface of said first chamber.   
   
   
       8 - 20 . (canceled)