Method for warning failure of selective catalytic reduction system in e.g. diesel vehicle, involves triggering alarm based on threshold according to which agent concentration is such that expansion volume of solution exceeds limit volume

摘要

The method involves estimating concentration of an active agent e.g. urea, in a nitrogen oxide reducing solution. An alarm is triggered based on two thresholds, if the concentration is insufficient, where failure of a selective catalytic reduction system (100) is compensated up to the first threshold by adaptation of injection of the solution, and is not compensated beyond the second threshold despite of the adaptation. The alarm is triggered based on a third threshold according to which the concentration is such that an expansion volume of the solution exceeds a limit expansion volume. The reducing solution is AdBlue(RTM: diesel emissions additive). An independent claim is also included for a selective catalytic reduction system.