Exhaust gas muffler

Abstract

An exhaust gas muffler for an engine, the exhaust gas muffler having a body, at least one inlet for the exhaust gas from the engine on the body, a baffled chamber in the body to receive exhaust gas from the at least one exhaust gas inlet, at least one exhaust gas outlet from the baffled chamber to vent the exhaust gas from the baffled chamber, at least one fresh-air inlet on the body, a heat exchange conduit extending into the baffled chamber between the fresh air inlet and the at least one exhaust gas outlet, the heat exchange conduit being sized and shaped to permit heat exchange between the fresh air and the exhaust gas in the baffled chamber, and a fresh air outlet on the heat exchange conduit, the fresh air outlet being sized, shaped and located relative to the exhaust gas outlet to permit the fresh air to mix with exhaust gases being vented from the baffled chamber to lower an exit temperature of the exhaust gases.

1 . An exhaust gas muffler for an engine, said exhaust gas muffler having: 
 (a) a body;    (b) at least one inlet for said exhaust gas from said engine on said body;    (c) a baffled chamber in said body to receive exhaust gas from said at least one exhaust gas inlet;    (d) at least one exhaust gas outlet from the baffled chamber to vent said exhaust gas from said baffled chamber;    (e) at least one fresh-air inlet on said body;    (f) a heat exchange conduit extending into said baffled chamber between said fresh-air inlet and said at least one exhaust gas outlet, said heat exchange conduit being sized and shaped to permit heat exchange between said fresh air and said exhaust gas in said baffled chamber; and    (g) a fresh air outlet on said heat exchange conduit, said fresh air outlet being sized, shaped and located relative to said exhaust gas outlet to permit said fresh air to mix with exhaust gases being vented from said baffled chamber to lower an exit temperature of said exhaust gases.    
   
   
       2 - 19 . (canceled)  
   
   
       20 . A method of cooling an exhaust gas inside of a muffler body, said method comprising the steps of: 
 (a) cooling said exhaust gases by conduction in at least a first internal muffler chamber by exposing said exhaust gases in said first muffler chamber to a heat exchange surface cooled by cooling air; and    (b) further cooling said exhaust gases by mixing said exhaust gases with said cooling air inside said muffler, before said exhaust gases are released from said muffler.    
   
   
       21 . A method as claimed in  claim 20  further including the step of drawing said cooling air into said muffler past said heat exchange surface.  
   
   
       22 . A method as claimed in  claim 21  wherein said step of drawing cooling air into said muffler further comprises forming a venturi adjacent to a cooling air conduit to create a low pressure region for drawing in said cooling air.  
   
   
       23 . A method as claimed in  claim 22  wherein said step of mixing said exhaust gases with said cooling air occurs adjacent to said venturi.