CO/O2 Zirconia Sensor Based on a Potentiometric Design

This paper describes the development and tests of a combined CO/O₂ zirconia sensor for on-board diagnosis of oxidation catalysts. To achieve accurate measurements, preliminary model scale experiments have been carried out. These tests consist in careful calibrations with synthetic gases, measurements in exhaust gas from a laboratory scale lean premixed methane-air burner, and comparisons with classical and FTIR gas analyzers. Accordingly, a new sensor has been designed and prototyped. Held in a spark plug type housing, it simultaneously monitors the CO, and O₂ content of the exhaust gas. Over the wide O₂ range of interest, model scale tests of the sensor with burnt gases have shown good agreement with laboratory analyzers. Closed loop experiments carried out with the same burner also demonstrate the CO/O₂ probe potential for combustion control.