Testing planar gas sensors based on yttria-stabilized zirconia with oxide electrodes in the exhaust gases of a spark ignition engine

Planar sensors based on tape-cast yttria-stabilized zirconia (YSZ) layers were tested for on-line detection of pollutants (NO(x), HCs and CO) in an Internal Combustion Engine (ICE) exhaust gases. Sensors with two parallel Pt finger electrodes, one coated with an oxide (La(0.8)Sr(0.2)FeO(3) or In(2)O(3)) thick film as sensing electrode, were fabricated. Sensors were located close to a commercial oxygen sensor, downstream the three-way catalytic converter of a FIAT fire 1242 c.c. spark ignition engine coupled to a dynamometer. Electromotive force (EMF) response of gas and oxygen sensors, both located downstream the catalytic converter, were recorded simultaneously. The EMF measurements were correlated with the exhaust gas concentrations measured by spectroscopic analytical equipment at the engine exhaust end.