Technical Paper
Response Characteristics of an Amperometric NOx-O2 Sensor at Non diffusion-Rate-Determining Conditions
2021-04-06
2021-01-0678
Experimental results are combined with a physical understanding of an amperometric NOx-O2 sensor to study the effect of three main operating parameters on the sensor behavior in non diffusion-rate-determining operating conditions. The sensor response to NOx concentration is examined over a range of sensor operating temperatures, reference cell potentials, and second sensing cell potentials. The results show that the sensor sensitivity increases gradually with the sensing cell voltage while the sensor output is almost linearly dependent on NOx concentration for cell voltages higher than ≈ 0.25 V. The results also reveal that reducing the reference cell potential from the typical cell potential (0.42 V) reduces the sensor cross-sensitivity to O2 particularly at high NOx concentrations (>600 [ppm]).