Direct Catalyst Conversion Sensor in Form of a Single Self-Heated Mixed-Potential Device

Abstract

Monitoring automotive exhaust gas aftertreatment components is required by law as part of the on-board diagnostics (OBD). For this purpose, a novel sensor device that determines directly the catalyst conversion could be used. It consists of a single, self-heated yttria stabilized ZrO2-based disc, separating two gas atmospheres. Two identical mixed-potential electrodes yield a voltage signal by comparing a certain trace gas concentration up- and downstream of the catalyst. Measurements in synthetic gas flow verify the theoretical assumption that this voltage signal only depends on the ratio of both concentrations, respectively on the conversion of the catalyst.

Keywords

• conversion sensor
• on-board diagnostics
• mixed-potential sensor
• electrochemical comparison
• high temperature co-fired ceramics (HTCC)