Method for operating a reagent metering system, device for carrying out the method, computer program and computer program product

摘要

A method for operating a reagent metering system which meters a reagent into an exhaust duct of an internal combustion engine upstream of an SCR catalytic converter, in which, after the metering operation is ended, at least part of the reagent metering system is emptied by back-suction by means of a reciprocating pump. The procedure according to the invention is distinguished in that during the back-suction, a stop determination determines the flight time of a reciprocating piston of the reciprocating pump from a starting time as far as the stop time, in that a comparator compares the flight time determined with a flight time threshold value, and in that the activation power of the reciprocating pump is reduced if the flight time determined is less than the flight time threshold value.

主权项

1. A method of operating a reagent metering system (10) which meters a reagent (14) into an exhaust duct (16) of an internal combustion engine (18) upstream of an SCR catalytic converter (20), the method comprising:
emptying at least part of the reagent metering system (10) by back-suction by a reciprocating pump after the metering operation has ended; determining a flight time (TZ) of a reciprocating piston of a reciprocating pump from a starting time (TS) as far as a stop time (TA) during the back-suction; comparing the flight time (TZ), by a comparator (50), with a flight time threshold value (52); and reducing an activation power of the reciprocating pump (30) if the flight time (TZ) is less than the flight time threshold value (52).