Device Model of the Zirconia Oxygen Sensor

The zirconia oxygen sensor, when used in closed-loop engine control systems, potentially provides the necessary measurement of air-fuel ratio for effective operation of a three-way catalyst. The present study was undertaken to determine the physical constants which define the performance of experimental oxygen sensors. An analytical method was used to derive, directly from measured sensor voltage vs air-fuel ratio curves, the physical constants of experimental sensors. Determinations of these constants permitted: (1) better understanding of the physical processes which govern behavior of oxygen sensors under various operating conditions, and (2) accurate device modelling of oxygen sensors which allowed realistic mathematical simulations of sensor performance.