Helwig Andreas, Hackner Angelika, Müller Gerhard, Zappa Dario, Sberveglieri Giorgio
Airbus Central R&T, D-81663 Munich, Germany.
Department of Applied Sciences and Mechatronics, Munich University of Applied Sciences, D-80335 Munich, Germany.
Sensors (Basel). 2018 Feb 3;18(2):453. doi: 10.3390/s18020453.
Metal oxide (MOX) gas sensors sensitively respond to a wide variety of combustible, explosive and poisonous gases. However, due to the lack of a built-in self-test capability, MOX gas sensors have not yet been able to penetrate safety-critical applications. In the present work we report on gas sensing experiments performed on MOX gas sensors embedded in ceramic micro-reaction chambers. With the help of an external micro-pump, such systems can be operated in a periodic manner alternating between flow and no-flow conditions, thus allowing repetitive measurements of the sensor resistances under clean air, R 0 , and under gas exposure, R g a s , to be obtained, even under field conditions. With these pairs of resistance values, eventual drifts in the sensor baseline resistance can be detected and drift-corrected values of the relative resistance response R e s p = ( R 0 - R g a s ) / R 0 can be determined. Residual poisoning-induced changes in the relative resistance response can be detected by reference to humidity measurements taken with room-temperature-operated capacitive humidity sensors which are insensitive to the poisoning processes operative on heated MOX gas sensors.
金属氧化物（MOX）气体传感器对多种可燃、易爆和有毒气体都能做出灵敏响应。然而，由于缺乏内置的自检功能，MOX气体传感器尚未能够进入对安全性要求极高的应用领域。在本研究中，我们报告了对嵌入陶瓷微反应腔中的MOX气体传感器进行的气敏实验。借助外部微型泵，此类系统可以周期性地运行，在有气流和无气流条件之间交替，从而即使在现场条件下也能获得在清洁空气中传感器电阻R₀以及气体暴露时传感器电阻Rgas的重复测量值。利用这些电阻值对，可以检测出传感器基线电阻的最终漂移，并确定相对电阻响应Resp = (R₀ - Rgas) / R₀的漂移校正值。通过参考由对加热的MOX气体传感器上起作用的中毒过程不敏感的室温操作电容式湿度传感器进行的湿度测量，可以检测出残留中毒引起的相对电阻响应变化。
