Method for diagnosing a reagent dosing system, apparatus for carrying out the method, computer program and computer program product

摘要

Proposed is a method for the diagnosis of a reagent dosing system (10), which doses a reagent into an exhaust duct (12) of an internal combustion engine (14), in which the reagent is brought from a reciprocating pump (32) to an operating pressure (34) in which a measure (76, 78) for the quantity of reagent (72) conveyed by the reciprocating pump (32) is detected, in which a metering rate set value (24) is predetermined by means of a metering valve (22) which is connected to a metering valve activation signal (26 ) with opening phases (60) and closing phases (62) is driven. The method is characterized in that as a measure (76, 78) for the delivered reagent quantity (72), a slow and a fast tracked average value (76, 78) are formed only during the closing phases (62) of the metering valve (26) determining a difference (82) between the averages (76, 78) and providing an error signal (86) if the difference (82) exceeds a difference threshold (84).