Electrochemical pumping cell for the detection of no and oxygen in exhaust gases built in thick-film technology

摘要

On board diagnosis (OBD) and lean burn concepts for car engines require NO{sub}x sensors for exhaust gas control. Due to high cross sensitivity to oxygen metal oxide sensors do not meet the requirements for OBD. In this paper we report on a sensor based on a diffusion limited pumping cell using stabilized zirconium-oxide (YSZ). YSZ-solid state electrolyte as oxygen sensor: Stabilized zirconium-oxide (YSZ) is a well known base material for λ-sensors. YSZ is a solid electrolyte. The charge carriers in this material are oxygen ions. Therefore if the oxygen concentrations at two surfaces of YSZ are different we can measure a voltage with suitable electrodes. This is the potentiometric measurement.