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1. (WO2013152780) A SELF-DIAGNOSING METHOD FOR DIAGNOSING A SCR SYSTEM

Pub. No.:    WO/2013/152780    International Application No.:    PCT/EP2012/001551
Publication Date: Fri Oct 18 01:59:59 CEST 2013 International Filing Date: Wed Apr 11 01:59:59 CEST 2012
IPC: F01N 11/00
F01N 3/20
Applicants: VOLVO LASTVAGNAR AB
NILSSON, Henrik
Inventors: NILSSON, Henrik
Title: A SELF-DIAGNOSING METHOD FOR DIAGNOSING A SCR SYSTEM
Abstract:
The invention concerns a self-diagnosing method for diagnosing a selective catalytic reduction (SCR) system of a vehicle, The vehicle comprises an internal combustion engine (2), the SCR system is arranged downstream of the engine (2), and the SCR system comprises at least one exhaust gas sensor (11, 12) being sensitive to nitrogen oxides (NOx) gas. The method comprises a first diagnosing sequence (Si) of: - ensuring that said vehicle is in a stationary state; controlling said engine (2) to operate in a high NOx output engine operating state and in a low NOx output engine operating state; registering an output signal of said at least one exhaust gas sensor (11, 12) when said engine (2) operates in each of said high NOx output engine operating state and low NOx output engine operating state; and diagnosing NOx measurement performance of said at least one exhaust gas sensor (11, 12) on the basis of said registered sensor output.