Exhaust system comprising a catalyst with a downstream filter and SCR catalyst

• Main Authors: ROBERT JAMES BRISLEY, ANDREW FRANCIS CHIFFEY
• Format: Patent
• Language: English
• Published: 14.12.2011
• Subjects: BLASTING; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; ENGINE PLANTS IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNALCOMBUSTION ENGINES; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES ORENGINES IN GENERAL; HEATING; LIGHTING; MACHINES OR ENGINES IN GENERAL; MECHANICAL ENGINEERING; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; STEAM ENGINES; THEIR RELEVANT APPARATUS; TRANSPORTING; WEAPONS

A method of treating nitrogen oxides NOx and particulate matter PM comprises the steps of catalytically converting nitrogen monoxide NO to nitrogen dioxide NO2 using a catalyst composition comprising a manganese oxide and at least one platinum group metal, converting NOx to nitrogen N2, by contacting a mixture of NO and NO2 with a nitrogenous reducing agent in the presence of a selective catalytic reduction SCR catalyst, and filtering PM to combust it in NO2. The catalyst composition may also comprise cerium oxide. An exhaust system is also claimed comprising a catalysed soot filter CSF with a portion of its substrate being catalysed and having an SCR downstream of it, where the catalyst on the substrate comprises a manganese oxide and at least one platinum group metal.