DEVICE AND METHOD COMPRISING DOUBLE REDUCING DEVICES AND A CATALYTICALLY COATED PARTICLE FILTER FOR TREATMENT OF AN EXHAUST STREAM

摘要

An exhaust treatment system comprising: a first oxidation catalyst to oxidize nitrogen compounds and/or hydrocarbon compounds in said exhaust stream; a first dosage device downstream of said first oxidation catalyst to supply a first additive into said exhaust stream; a first reduction catalyst device downstream of said first dosage device for reduction of nitrogen oxides in said exhaust stream using said first additive; a particulate filter, comprising a catalytically oxidizing coating downstream of said first reduction catalyst device to catch soot particles and oxidize one or several of nitrogen oxide and incompletely oxidized carbon compounds in said exhaust stream; a second dosage device downstream of said particulate filter to supply a second additive into said exhaust stream; and a second reduction catalyst device downstream of said second dosage device for a reduction of nitrogen oxides in said exhaust stream, using at least one of said first and second additive.

主权项

1. An exhaust treatment system, arranged for treatment of an exhaust stream, which results from a combustion in a combustion engine, said system comprising:
a first oxidation catalyst, arranged to oxidize compounds comprising one or several of nitrogen, carbon and hydrogen in said exhaust stream; a first dosage device, arranged downstream of said oxidation catalyst, and arranged to supply a first additive in said exhaust stream; a first reduction catalyst device, arranged downstream of said first dosage device, and arranged for reduction of nitrogen oxides NOx in said exhaust stream with the use of said first additive; a particulate filter, at least partly comprising a catalytically oxidizing coating, which is arranged downstream of said first reduction catalyst device, and is arranged to catch and to oxidize soot particles, and to oxidize one or several of nitrogen oxide NO and incompletely oxidized carbon compounds in said exhaust stream; a second dosage device, arranged downstream of said particulate filter, and arranged to supply a second additive in said exhaust stream; and a second reduction catalyst device, arranged downstream of said second dosage device, and arranged for reduction of nitrogen oxides NOx in said exhaust stream, through the use of at least one of said first and said second additives.