| 摘要 |
The invention relates to a method pertaining to an SCR system wherein a reducing agent is provided to an exhaust gas stream from an engine (230) for purifying said exhaust gas with respect to among other things content of NOx, wherein said SCR system comprises an SCR catalyst (265) and an upstream of said SCR catalyst (265) arranged and for SCR function coated filter (260), a first dosing unit (250a) for provision of reducing agent being arranged upstream of said filter (260) and a second dosing unit (250b) for provision of reducing agent being arranged upstream of said SCR catalyst (265) and downstream of said filter (260). The method comprises the steps of: - continuously determining a differential pressure (P) over said filter (260); - where applicable, controlling dosing of said first and said second dosing unit (250a, 250b) on the basis of the thus determined differential pressure (P) over said filter (260). The invention relates also to a computer programme product comprising programme code (P) for a computer (200; 210) for implementing a method according to the invention. The invention relates also to an SCR system and a motor vehicle equipped with the SCR system. |
