METHOD FOR DIAGNOSING A REAGENT METERING SYSTEM DEVICE FOR CARRYING OUT THE METHOD COMPUTER PROGRAM AND COMPUTER PROGRAM PRODUCT

摘要

The present invention relates to a method for diagnosing a reagent metering supply system (10) for metering a reagent and supplying the reagent into an exhaust gas channel (12) of an internal combustion engine (14). In this method, an operating pressure (34) is applied to the reagent by the reciprocating piston pump (32), and scales (76, 78) of an amount of reagent (72) transferred by the reciprocating piston pump (32) are detected. A measurement supply speed target value (24) is previously set by using a measurement supply valve (22) controlled by a measurement supply valve control signal (26) having an opened phase (60) and a closed phase (62). According to the method, average values (76, 78) as the scales (76, 78) of the amount of transferred reagent (72), which have been rapidly updated and slowly updated only during the close phases (62) of the measuring supply valve (26), are calculated, and a variation (82) between the average values (76, 78) is calculated. When the variation (82) exceeds a variation critical value (84), an error signal (86) is displayed.