METHOD FOR DIAGNOSING A DOSING VALVE OF AN EXHAUST GAS TREATMENT DEVICE AND DEVICE FOR IMPLEMENTING THE METHOD.

摘要

Suggested are a procedure for diagnosing a metering valve (14) of an exhaust gas treatment device (22), which doses a reagent (16) into the exhaust gas area (11) of a combustion process, whereby the reagent (16) is brought to a metering pressure (p_Ds) by a pump (17) and which is dosed by the metering valve (14), at which the diagnosis is undertaken by evaluating a pressure drop (50, 51, 60, 61) of the reagent (16), and a device for implementing the procedure. At first the pump (17) is switched off. Subsequently the metering is continued during a diagnosis metering operation. The reagent quantity (m) that has been dosed is determined during the diagnosis metering operation. Not until reaching a dosing quantity threshold (m_Lim) the evaluation of the pressure drop (50, 51, 60, 61) is terminated.