Patent ID: 8707689

Claim:
An exhaust system for an internal combustion engine, said exhaust system comprising, in combination: an elongated muffler shell defining a muffler shell interior; an elongated tube positioned within said muffler shell interior extending along the elongated muffler shell and defining a tube interior for receiving exhaust gas from the internal combustion engine, said elongated tube in said muffler shell interior defining a plurality of spaced openings about the periphery thereof along the length thereof, and said elongated muffler shell and said elongated tube spaced apart and defining an open-ended first exhaust gas passageway therebetween surrounding the elongated tube and extending along the elongated tube in said muffler shell interior; and exhaust flow modification structure within said tube interior having an outer surface spaced from said elongated tube whereby said elongated tube and said exhaust flow modification structure define an exhaust gas flow path surrounding said outer surface and extending the length of said exhaust flow modification structure, said outer surface configured to produce a laminar flow of said exhaust gas and to modify flow speed of said exhaust gas due to the venturi effect within said tube interior, said exhaust flow modification structure defining a second exhaust gas passageway in the form of an internal exhaust gas flow passageway through which a portion of the exhaust gas in said tube interior flows during operation of the internal combustion engine, said internal exhaust flow passageway configured to modify flow speed of the portion of exhaust gas due to the venturi effect, said exhaust flow modification structure having an inner surface defining said internal exhaust gas flow passageway and said inner surface configured to form an internal venturi having a converging inlet nozzle portion for receiving exhaust gas from said elongated tube, a diverging outlet diffuser portion for discharging gas received thereby back to said elongated tube and a gas flow restricting throat portion interconnecting said converging inlet nozzle portion and said diverging outlet diffuser portion.