Method for detecting resistance of region in e.g. oxygen ion-conducting solid electrolyte, of lambda probe for detection of fuel residue of combustion engine, involves determining electrode temperatures based on predetermined relationship

摘要

The method involves determining combined impedances between an inner pumping electrode (12), an exhaust air electrode (22) and an exhaust gas electrode (32) of a sensor for circuit configurations of voltage and/or current detected at the electrodes. Single impedance of a region (72) in an oxygen ion-conducting solid electrolyte (70) is determined from the determined impedances and impedance of resistors (42, 44, 46) between the electrodes. Temperature of the electrodes is determined based on a predetermined relationship between the single impedance and temperature dependence in the region. An independent claim is also included for a sensor for detecting a substance, comprising a resistance detecting circuit.