FeSrTiO3-based resistive oxygen sensors for application in diesel engines

SrTi0.4Fe0.6O2.8 (STFO60) powders were prepared by self-propagating high-temperature synthesis (SHS) and subsequent ball-milling (BM) treatment, and then deposited on an interdigited alumina substrate by screen-printing to fabricate a planar resistive oxygen sensor for direct injection (DI) diesel engines. The electrical characteristics and response to oxygen of the STFO60 sensor have been carefully examined first in a bench system with synthetic gases thus simulating diesel exhaust composition. The results obtained highlighted the promising performances of the sensor in terms of the temperature resistance independence as well as sensor response at the high oxygen concentrations typical of diesel engines. Cross-sensitivity tests also indicated that the sensor response is not influenced by main components in the exhausts, such as HC, CO2, NOx, CO. The STFO60 sensor was then tested as an oxygen probe on a diesel engine car under real driving conditions. Road tests confirmed that the performances of the resistive sensor are comparable with those of a commercial lambda probe