Combination exhaust gas post treatment/muffler device in the exhaust gas section of an internal combustion engine

A combination exhaust gas post treatment/muffler device in the exhaust gas section of an internal combustion engine, comprising:

• a muffler that is spatially delimited by a front end wall, a rear end wall, and a peripheral outer wall, wherein said muffler is provided with an inlet for exhaust gas that is to undergo post treatment;
• at least one exhaust gas post treatment/muffler module built into said muffler as a system core, wherein said at least one module is provided with a housing composed of a plurality of housing portions;
• at least one preliminary oxidation catalytic converter disposed in a first one of said housing portions, wherein said at least one catalytic converter significantly increases an amount of NO2 in exhaust gas flowing through said muffler, wherein said first housing portion is followed by a second one of said housing portions, which widens in a funnel-shaped manner and delimits a transfer chamber, and wherein said second housing portion is followed by a third one of said housing portions,
• at least one exhaust gas post treatment device disposed in said third housing portion, wherein said third housing portion is followed by an end housing portion for collecting cleaned exhaust gas and discharging said cleaned gas from said muffler in a muffled manner;
• and
• wherein all of said housing portions of said at least one module are made of ferritic or austenitic stainless steel that is resistant to sulfuric acid, and wherein said front end wall, said rear end wall, said peripheral outer wall, said inlet, and any inner element of said muffler disposed externally of said at least one module are made of an unalloyed sheet steel that is coated with aluminum or other material for protection against corrosion.