Method for plausibility checking of a sensor signal of a concentration sensor arranged in an SCR catalyst system

摘要

The invention relates to a method (100) for checking the plausibility of a sensor signal of a concentration sensor arranged in an SCR catalyst system. The concentration sensor is designed and set up to measure a concentration of an HWL arranged in a tank. To determine the concentration, an ultrasound signal generated by an ultrasound source is sent over a predetermined distance and the concentration of the HWL is determined from a sound propagation time determined by means of an ultrasound sensor. There is a regulation of the ultrasound signal which, when the ultrasound sensor functions properly, regulates the ultrasound signal such that a signal amplitude measured by the ultrasound sensor lies in a predetermined amplitude range. At least one control variable of the control of the ultrasound signal is used to check the plausibility of the sensor signal of the concentration sensor (110).