| abstract |
"EXHAUST SYSTEM FOR A POOR BURN INTERNAL COMBUSTION ENGINE, POOR BURN INTERNAL COMBUSTION ENGINE, AND PROCESS TO TREAT A NO ~ X ~ IN A POOR BURN INTERNAL FUEL ENGINE" The exhaust (10) for a poor burning internal combustion engine comprises a nitrogen oxide (NO ~ x ~) absorber (28), a catalyst (30) for catalyzing the selective catalytic reduction (SCR) of NO ~ x ~ with a NO ~ x ~ specific reagent, the first means (18, 22) for introducing a NO ~ x ~ specific reagent or a precursor thereof into an exhaust gas upstream of the SCR catalyst (30) and the medium ( 24) to control the introduction of the specific NO ~ x ~ reagent or precursor thereof into the exhaust gas via the first introduction medium (18,22), wherein the SCR catalyst (30) is positioned upstream of the NO ~ x ~ absorber (28) and optionally with the NO ~ x ~ absorber, wherein the control means (24) is positioned to introduce the specific NO ~ x ~ reagent or the precursor thereof into the exhaust gas via the first introduction medium (18, 22) only when the SCR catalyst (30) is active, whereby the exhaust from NOx specific reagent to the atmosphere is substantially avoided. |