Advancements in both combustion system design and emission control technologies have allowed more efficient diesel engines to meet stringent exhaust emissions standards. With very stringent emission regulations currently in place, combustion system design and combustion management are used in conjunction with available exhaust after treatment technologies for optimal reduction of emissions to meet regulatory targets. Current diesel vehicles in the US are equipped with a diesel oxidation catalyst (DOC) to control CO and HC emissions, a diesel particulate filter (DPF) to control particulate matter (PM) and selective catalyst reduction (SCR) or lean-NOx trap (LNT) to control NOX emissions. In SCR, NOx is reduced to H2O and N2 over a catalyst through the injection of an ammonia source provided by the onboard storage of diesel exhaust fluid (DEF), typically a mixture of urea and de-ionized water. Mixed-potential sensors are electrochemical devices that develop a non-Nernstian potential due to differences in the redox kinetics of various gas species at each electrode/electrolyte gas interface1,2. The difference in the steady-state redox reaction rates between the “fast” and “slow” electrodes gives rise to the measured mixed potential response. A patented LANL sensor design incorporates dense electrodes and a porous electrolyte and reproducible and stable sensors are prepared using a high temperature ceramic co-fire approach3. The use of dense electrodes minimizes deleterious heterogeneous catalysis, and the increased morphological stability of dense electrodes yields a robust electrochemical interface, increasing lifetime durability4. LANL has worked in collaboration with Electro-Science Laboratories (ESL, King of Prussia, PA) to fabricate planar mixed-potential sensors via the readily scalable, cost-effective high temperature co-fired ceramic (HTCC) technology already employed in the manufacturing of planar O2 l-sensors. In this work, we present recent results from evaluating the performance of pre-commercial prototype mixed potential-based NOx and NH3 sensors under engine exhaust conditions at the National Transportation Research Center (NTRC) on a GM 1.9L CIDI diesel engine. T

Response characteristics of pre-commercial mixed potential NOx and NH3 sensors in diesel engine exhaust

254th National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.