Auswertevorrichtung für das Signal einer Sauerstoffsonde

The invention is directed to an evaluating arrangement 10 for the probe signal of a heated amperometric oxygen probe 11 which is mounted in the flow of the exhaust gas from an internal combustion engine 13. The heater unit 18 of the probe is continuously operated with such a heater voltage that the internal resistance of the prove remains constant. However, for this reason, an ever increasing probe temperature (that is, an however, leads to an unwanted increase of the probe signal and this increase must be compensated. For this compensation, the realization is utilized that the increase of the probe temperature is clearly connected to the increase of the heater voltage. The amount of the increase of the heater voltage is determined by comparison measurements in a calibration operating state of the engine. A corrective value is formed from the detected change of the heater voltage and is mathematically coupled to the measurement signal in order to obtain a corrected measurement signal which exhibits neither temperature-caused errors nor deterioration-caused errors.