Rear muffler assembly

1. 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.

2. The rear muffler assembly according to claim 1 ,

wherein said first chamber contains said issue orifice of said first exhaust gas routing pipe, said first chamber having a partition formed with perforated holes therein, oriented toward said second chamber;

the rear muffler assembly further including a perforated sheet metal pot surrounding said second chamber

and an insulting material surrounding said perforated sheet metal pot.

3. The rear muffler assembly according to claim 2 , wherein:

said third chamber follows downstream of said second chamber and has partitions closing said third chamber; and

said third perforated pipe section of said second exhaust gas routing pipe is has an insulating material surrounding said third perforated pipe section.

4. The rear muffler assembly according to claim 3 , wherein:

said first perforated pipe section is disposed in said third chamber; and

said third perforated pipe section of said second exhaust gas routing pipe is disposed matching said first perforated pipe section in said third chamber.

5. The rear muffler assembly according to claim 1 , wherein:

said third chamber follows downstream of said second chamber and has partitions closing said third chamber; and

said third perforated pipe section of said second exhaust gas routing pipe is disposed in said third chamber and has an insulating material surrounding said third perforated pipe section.

6. 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 first perforated pipe section being disposed entirely in said third chamber;

said second exhaust gas routing pipe including a second perforated pipe section disposed entirely in said second chamber and a third perforated pipe section disposed entirely 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 into said issue orifice; and

a second branched-off exhaust gas stream positively discharged from said third perforated pipe section into said first perforated pipe.

7. The rear muffler assembly according to claim 6 ,

wherein said first chamber contains said issue orifice of said first exhaust gas routing pipe, said first chamber having a partition formed with perforated holes therein, oriented toward said second chamber;

the rear muffler assembly further including a perforated sheet metal pot surrounding said second chamber and an insulting material surrounding said perforated sheet metal pot.

8. The rear muffler assembly according to claim 7 , wherein:

said third chamber follows downstream of said second chamber and has partitions closing said third chamber; and

said third perforated pipe section of said second exhaust gas routing pipe has an insulating material surrounding said third perforated pipe section.

9. The rear muffler assembly according to claim 8 , wherein said third perforated pipe section is disposed in said third chamber matching said first perforated pipe section.

10. The rear muffler assembly according to claim 6 , wherein:

said third chamber follows downstream of said second chamber and has partitions closing said third chamber; and

said third perforated pipe section of said second exhaust gas routing pipe has an insulating material surrounding said third perforated pipe section.