A method and apparatus for correcting a quality signal of an ultrasonic quality sensor, controller program and controller program product used in a reagent dosing system

摘要

A method is proposed for correcting a quality signal (38) of an ultrasonic quality sensor (36) used in a reagent dosing system (10) which has a urea-water solution (14) stored in a tank (12) of ultrasonic quality -Qualitätssensor (66) is measured upstream of an SCR catalyst (20) metered. The method according to the invention is characterized in that the ultrasonic quality sensor (36) determines the transit time of an ultrasound signal (50) in a jib (52) surrounded by the urea-water solution (12) and provides it as a quality signal (38) and the quality signal (38) is corrected by means of a correction signal (62) which reflects a construction-related relationship between the quality signal (38) and the temperature (66) of the urea-water solution (14).