Dynamometer Testing of Planar Mixed-Potential Sensors

摘要

Mixed-potential sensors for vehicle on-board emissions monitoring applications have been fabricated in an automotive planar sensor configuration using high temperature ceramic co-fire methods. The sensing element consists of dense Pt and LaSrCrO electrodes and a porous 3 mol% YSZ electrolyte. This sensor construct exhibits preferential selectivity to NO_x (NO+NO_2) when operated at a positive current bias. The performance of the planar sensors under engine-out conditions was recently evaluated at the Oak Ridge National Laboratory National Transportation Research Center on a GM 1.9L CIDI diesel engine. The sensor response qualitatively tracked transients in NO_x measured via FTIR under transient engine operation. Additionally, quantitative correlation between sensor voltage response and total NO_x concentration was obtained under steady-state engine speed and load while varying exhaust gas recirculation (EGR) levels.