Resistive oxygen sensor using ceria-zirconia sensor material and ceria-yttria temperature compensating material for lean-burn engine

Temperature compensating materials were investigated for a resistive oxygen sensor using Ce_0.9Zr_0.1O₂ as a sensor material for lean-burn engines. The temperature dependence of a temperature compensating material should be the same as the sensor material; therefore, the Y concentration in CeO₂-Y₂O₃ was optimized. The resistance of Ce_0.5Y_0.5O_2-δ was independent of the air-to-fuel ratio (oxygen partial pressure), so that it was confirmed to function as a temperature compensating material. Sensor elements comprised of Ce_0.9Zr_0.1O₂ and Ce_0.5Y_0.5O_2-δ were fabricated and the output was determined to be approximately independent of the temperature in the wide range from 773 to 1,073 K.