Air-fuel ratio determining apparatus comprises air-fuel ratio sensor, sensor arrangement controller switch, element impedance determining apparatus, and diagnostic device

摘要

The air-fuel ratio determining apparatus comprises an air-fuel ratio sensor, a sensor arrangement controller switch, an element impedance determining apparatus, and a diagnostic device. The air-fuel ratio determining apparatus comprises: (a) an air-fuel ratio sensor with a sensor arrangement which determines the oxygen concentration or the concentration of non-combusted gas by applying a voltage to a boundary stream; (b) a sensor arrangement controller switch; (c) an element impedance determining apparatus for determining the impedance of an oxygen ion conducting element in the sensor arrangement by the application of an alternating voltage to the sensor arrangement; and (d) a diagnostic device determining and diagnosing errors based on the determined element impedance.