A PROCESS AND DEVICE FOR DETERMINING THE INTERNAL RESISTANCE OF LAMBDA PROBES AND FOR HEATING REGULATION USING THE INTERNAL RESISTANCE

摘要

The internal resistance of a lambda probe is determined by applying a timed inverse d.c. voltage to the probe via a series resistor, measuring the output voltages with the inverse voltage on and off and calculating the internal resistance from the measured values and known internal resistances. Besides the components of a prior art device, this process requires only a series resistor and a switch. Measurement may be completed within short times without reaching excessively high d.c. loads which could affect the useful life. The measured internal resistance is compared with a reference resistor and the scanning ratio for a fixed-frequency probe heater may be determined with the aid of the deviation thus obtained.