Exhaust System for Internal Combustion Engine Having Temperature Variable Acoustics

A muffler for engagement to an exhaust gas conduit exiting an internal combustion engine, comprising:

• a housing, said housing having a housing wall surrounding an interior cavity;
• an inlet conduit communicating with said interior cavity, said inlet adapted for sealed engagement to an exhaust pipe communicating with said engine;
• an exhaust conduit communicating with said interior cavity, said exhaust conduit providing a exit for exhaust gasses communicated through said interior cavity from said inlet conduit;
• a first pathway defined by a first conduit communicating between said inlet aperture and said exhaust conduit, said first pathway defining a means for sound suppression for said exhaust gasses communicating therethrough;
• a second pathway defined by a second conduit communicating between said inlet aperture and said exhaust conduit, said second pathway defining a second means for sound suppression;
• said first means for sound suppression having a higher said sound suppression capability than said second means for sound suppression;
• said first conduit communicating through a temperature actuated first valve, said first valve having a cold position wherein allows communication of said exhaust gasses to said exhaust conduit and having a heated position wherein it is closed and prevents communication of said exhaust gasses to said exhaust conduit from said inlet conduit;
• said first valve actuated from said cold position to said heated position by heat from said exhaust gasses;
• said second conduit communicating through a temperature actuated second valve, said second valve having a cold position preventing a communication of said exhaust gasses to said exhaust conduit and having a heated position allowing a communication of said exhaust gasses to said exhaust conduit from said inlet conduit;
• and
• said exhaust gasses communicating through said muffler along said first pathway when said first and second valves are in respective said cold positions and through said second pathway when said first and second valves are heated by said exhaust gasses and move to said respective heated positions, whereby increased noise suppression is provided to said internal combustion engine by said first pathway when said engine is cold and reduced noise suppression is provided once said engine warms.