Exhaust gas sensor having two titania ceramic elements.

摘要

An exhaust gas sensor has first and second titania ceramic elements (46, 48) which have electrical resistances varying as a function of both the temperature and the composition of exhaust gases from internal combustion engines to which the elements are exposed. The first and second titania elements are connected in series circuit in the utilization of the sensor and the resistance of the second element over the operating temperature range of the exhaust gas sensor compensates the signal of the first titania element in a manner that produces a desired signal. The desired signal is a result of variation of the second titania element resistance values when exhaust gases cycle between lean-mixture and rich-mixture compositions. The resistance values of the second titania element are intermediate the corresponding resistances of the first titania element over the temperature range. The second titania element is more dense than the first titania element. It has a density in the range from 3.2 g/cm<3> to 3.8 g/cm<3>, i.e., between about 76% and 90% of theoretical density.