System for treating an exhaust gas
AssigneeJohnson Matthey Public Limited Company
InventorsCeren AYDIN, Patrick BANNON, Penelope MARKATOU
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Abstract
A system for treating an exhaust gas from a vehicular lean burn internal combustion engine comprises, in order: (i) a first means for injecting a nitrogenous reductant; (ii) a first selective catalytic reduction (SCR) catalyst; (iii) a catalysed soot filter (CSF) comprising a filter substrate; and (iv) a second selective catalytic reduction (SCR) catalyst, wherein the CSF comprises palladium and, optionally, platinum, wherein a weight ratio of palladium to platinum in the CSF is greater than 1:1 and wherein a total platinum group metal content of the CSF is from 0.3 to 2gft3.
Claims19
A system for treating an exhaust gas from a vehicular lean burn internal combustion engine, the system comprising, in order:
- (i) a first means for injecting a nitrogenous reductant;
- (ii) a first selective catalytic reduction (SCR) catalyst;
- (iii) a catalysed soot filter (CSF) comprising a filter substrate;
- and
- (iv) a second selective catalytic reduction (SCR) catalyst,
- wherein the CSF comprises palladium and, optionally, platinum, wherein a weight ratio of palladium to platinum in the CSF is greater than 1:1 and wherein a total platinum group metal content of the CSF is from 0.3 to 2 gft−3.
Dependencies are inferred from the claim text.