New Total-NOx Sensor Based on Mixed Potential for Automobiles 1999-01-1280
The new total-NOx sensors were made by laminating YSZ green sheets, on which electrodes including an NOx sensing electrode, an oxygen pump, an NOx conversion electrode, a Pt heater and a pair of thermocouples were printed and fired. The exhaust gas containing NOx(NO and NO2), HC and CO were introduced into the cavity inside the sensor body, then HC and CO were oxidized to non-interference gases. NO was subsequently converted to NO2 by the NOx conversion electrode at the second half cavity. Consequently, NO and NO2 in the exhaust can be detected in total-NOx concentration as low as 10 ppm by the sensing electrode based on the mixed potential.