Patent ID: 7562741

Claim:
A rear muffler assembly for an internal combustion engine, the rear muffler assembly comprising: first and second mufflers through which exhaust gases flow and which are separated from one another; each of said first and second mufflers including: an exhaust gas routing pipe assembly for exhaust gas delivery and discharge to an exhaust pipe which follows downstream, said exhaust gas routing pipe assembly extending through a first chamber, a second chamber and a third chamber; said exhaust gas routing pipe assembly including a first exhaust gas routing pipe and a second exhaust gas routing pipe; said first exhaust gas routing pipe including an issue orifice and a first perforated pipe section; said second exhaust gas routing pipe including a second perforated pipe section disposed in said second chamber and a third perforated pipe section disposed in said third chamber; a temporarily closeable exhaust gas shutoff flap in communication with said exhaust gas routing pipe assembly so as to form, when closed: a first branched-off exhaust gas stream positively discharged from said second perforated pipe section of said second exhaust gas routing pipe flowing into said issue orifice of said first exhaust gas routing pipe; and a second branched-off exhaust gas stream positively discharged from said third perforated pipe section in said third chamber flowing into the first perforated pipe section of said first exhaust gas routing pipe.