Exhaust chamber for the exhaust line of an automobile

An exhaust chamber for a motor vehicle exhaust line, the exhaust chamber (1) comprising:

• a main envelope (2) defining a main enclosure (4) and having an exhaust gas inlet (6) and an exhaust gas outlet (8), the main envelope (2) comprising a rolled sleeve (26) having a longitudinal central axis and defining mutually axially opposite upstream and downstream openings, said rolled sleeve being made of a single unitary sheet of metal rolled around the central axis, said sheet having two longitudinal edges joined together and secured to one another, the sleeve having a closed cross section perpendicularly to the central axis, and
• at least one saucer-shaped shell (20) having an opening defined by a peripheral edge (22) of the shell (20), the or each shell (20) being tightly connected to an outside surface (24) of the sleeve (26) of the main envelope (2) along the peripheral edge (22), the shell (20), with the sleeve (26), defining a secondary enclosure (40),
• the sleeve of the main envelope (2) having, beneath the shell (20), a plurality of perforations (48) for placing the main enclosure (4) in communication with the secondary enclosure (40),
• wherein the sleeve (26) of the main envelope (2) has, in a first area located beneath the shell (20), at least one slot (52, 54, 56) for increasing the elasticity of said first area, and/or the sleeve (26) the main envelope (2) has, in a second area that is not covered by the shell (20), at least one rib (58, 60, 62, 64, 72, 74) for increasing the stiffness of said second area.