Output Characteristic Analysis and Control Strategy Optimization of Yttria-Stabilized Zirconia Solid-Sate Electrolyte Based Amperometric Nitrogen Oxide Sensor

Abstract

A fully open nitrogen oxide(NOx)sensor test system based on LabVIEW and digital multimeters is designed to improve the accuracy of the yttria-stabilized zirconia solid-sate electrolyte-based amperometric NOx sensor. The working principle of the NOx sensor is analyzed, and the control strategy is optimized. Each functional module of the sensor is tested individually to achieve the optimized operation temperature and the limited output current characteristic curves of the main oxygen pump, auxiliary oxygen pump, and NOx measuring pump. It is found that the sensor shows excellent saturized current platforms under limiting conditions and the limited current increases with working temperature. In addition, a linear relationship between the limited current and the NOx concentration is observed under the constant-voltage mode in oxygen-containing atmosphere. A constant-voltage control strategy is further proposed for the NOx sensor operating in the oxygen-containing environment.