DEVICE AND METHOD FOR FAULT-TRACING PERTAINING TO AN SCR SYSTEM

摘要

The invention concerns a method for troubleshooting an SCR system comprising a dosing unit (250) for dosing reducing agent into the exhaust duct (290) of an engine upstream of an SCR catalytic converter (270) to reduce the NOx level in an exhaust flow from said engine, comprising the step of: - determining (s310) the NOx level in the exhaust flow downstream of said SCR catalytic converter (270). The method comprises the steps of: - gradually changing (s320) the dosing of said reducing agent under predetermined operating conditions for said SCR catalytic converter (270); - determining (s330) whether the SCR catalytic converter (270) is able to reduce said NOx level in the exhaust flow downstream of said SCR catalytic converter (270) to a predetermined extent during said gradually changed dosing; and - deciding (s340), based on the result of said determination, whether said SCR catalytic converter (270) is defective or not from the standpoint of NOx level reduction. The invention also concerns a computer program product containing program code (P) for a computer (200; 210) for implementing a method according to the invention. The invention also concerns a device for troubleshooting an SCR system and a motor vehicle that is equipped with the device.