An integrated solution for NOx-reduction and -control under lean-burn conditions

Upcoming emission regulations order highly effective NO(x)-reduction systems in lean-burn engines requiring new catalytic materials and integrated control of the reduction process. Thus, new approaches for NO(x)-reduction and its monitoring over an On-Board-Diagnostic (OBD) system are suggested throughout the globe. A promising attempt is the development of a catalytic system having an integrated NO(x)-sensor, based on selective catalytic reduction process and impedance sensors. The study displays the results achieved both with a perovskite type of self-regenerative catalyst functioning by H(2)-reductant and with impedance NO(x)-sensors. The catalysts were tested at the temperature range of 150 degrees C to 360 degrees C yielding NO(x) conversion rates of 92% with high selectivity to N(2). Impedance sensors having NiCr(2)O(4)- and NiO-SE and PYSZ- and FYSZ-electrolytes are developed and tested at 600 degrees C under lean atmosphere (5 vol. % O(2)). Better sensing behaviour towards NO and lower cross-selectivity towards O(2), CO, CO(2) and CH(4) have been observed with sensors having NiO-SE.