Muffler assembly unit

1. A muffler assembly unit for an exhaust system of an internal combustion engine, the muffler assembly unit comprising:

a muffler comprising a muffler housing that is elongated along a housing longitudinal axis;

a housing jacket enclosing the muffler housing; and

at least one air guiding bulge provided on the housing jacket,

wherein:

the housing jacket has at least one rib support area and is supported on an outer side of the muffler housing in the at least one rib support area without being fixed there to the muffler housing; and

the housing jacket is permanently connected to the muffler housing by welding only at a plurality of connection areas positioned in the same length area in a direction of the housing longitudinal axis in a connecting length area in a longitudinal center in the direction of the housing longitudinal axis of the muffler housing, and wherein the housing jacket is not permanently connected to the muffler housing starting from the connecting length area in the direction towards axial end areas of the housing jacket for providing housing jacket sections of substantially similar length extending from the connecting length area to both axial end areas of the housing jacket that are not fixed to the muffler housing.

2. The muffler assembly unit in accordance with claim 1 , wherein the muffler housing comprises:

a circumferential wall that is elongated in a direction of the longitudinal axis of the housing; and

front walls, one of the front walls being disposed at each of both axial end areas of the circumferential wall, wherein the housing jacket fully encloses the circumferential wall in at least one length area of same.

3. The muffler assembly unit in accordance with claim 2 , wherein:

the housing jacket fully encloses the circumferential wall essentially in an entire length area; or

the housing jacket overlaps at least one front wall; or

the housing jacket fully encloses the circumferential wall essentially in an entire length area and the housing jacket overlaps at least one front wall.

4. The muffler assembly unit in accordance with claim 1 , wherein:

the housing jacket comprises at least two jacket shells connected to one another; and

the at least one air guiding bulge is provided on at least one jacket shell of the at least two jacket shells.

5. The muffler assembly unit in accordance with claim 4 , wherein:

the two jacket shells are connected to one another by connection in substance; or

the two jacket shells are positive locking connected in connecting edge areas adjoining one another; or

at least one jacket shell is permanently connected, by a connection in substance, to the muffler housing; or

any combination of the two jacket shells are connected to one another by connection in substance and the two jacket shells are positive locking connected in connecting edge areas adjoining one another and at least one jacket shell is permanently connected, by a connection in substance, to the muffler housing.

6. The muffler assembly unit in accordance with claim 4 , wherein:

the jacket shells are configured as shaped sheet metal parts; and

the at least one air guiding bulge is integrated into at least one of the jacket shells.

7. The muffler assembly unit in accordance with claim 1 , wherein:

the muffler housing comprises at least one housing bulge; and

the housing jacket has a receiving opening or receiving bulge or receiving opening and receiving bulge receiving the housing bulge in at least some areas in association with the at least one housing bulge.

8. The muffler assembly unit in accordance with claim 1 , further comprising at least one exhaust gas pipe projecting from the muffler housing, wherein the housing jacket has an exhaust gas pipe passage opening in an area of the at least one exhaust gas pipe and in an adjoining area of the two jacket shells.

9. The muffler assembly unit in accordance with claim 1 , wherein the at least one air guiding bulge is closed in a direction of the housing longitudinal axis.

10. The muffler assembly unit in accordance with claim 1 , wherein the at least one air guiding bulge extends in a direction of the housing longitudinal axis essentially along an entirety of the muffler housing.

11. The muffler assembly unit in accordance with claim 1 , wherein:

the housing jacket encloses the muffler housing and cooperates with the muffler housing to define a gap intermediate space; and

a layer of insulating material is disposed in the gap intermediate space or the gap intermediate space is not filled.

12. The muffler assembly unit in accordance with claim 1 , wherein:

the housing jacket has a greater distance to the muffler housing in an area of the at least one air guiding bulge than in areas adjacent to the at least one air guiding bulge, whereby a distance between the housing jacket and the muffler housing increases up to a maximum distance in the area of the at least one air guiding bulge, starting from the areas adjacent to the at least one air guiding bulge.

13. An assembly unit for an exhaust system of an internal combustion engine, the assembly unit comprising:

an exhaust housing elongated along a longitudinal axis;

a housing jacket enclosing said exhaust housing, said housing jacket having an air guiding bulge relative to said exhaust housing;

a plurality of connection areas fixing said housing jacket to said exhaust housing, each of said plurality of connection areas being positioned at a central longitudinal position of said exhaust housing, said housing jacket not being longitudinally fixed to said exhaust housing at longitudinal positions spaced from said central longitudinal position.

14. An assembly unit in accordance with claim 13 , wherein:

said housing jacket has axial ends, said central longitudinal position being arranged equally distanced from said axial ends of said housing jacket.

15. An assembly unit in accordance with claim 14 , wherein:

a muffler is arranged in said exhaust housing.

16. An assembly unit in accordance with claim 13 , wherein:

a muffler is arranged in said exhaust housing.

17. An assembly unit in accordance with claim 16 , wherein:

said plurality of connection areas are arranged at a single longitudinal position of said exhaust housing.

18. An assembly unit in accordance with claim 13 , wherein:

said plurality of connection areas are arranged at a single longitudinal position of said exhaust housing.