PURPOSE: To detect the concentration of oxygen speedily even at a low temperature by providing a plurality of heater layers in an insulator layer in an oxygen sensor consisting of a lamination in which the first electrode layer, an oxygen ion-conductive solid electrolyte layer and the second electrode layer are laminated in the mentioned order on an insulator layer.
CONSTITUTION: The first electrode layer 12, an oxygen ion-conductive solid electrolyte layer 13 and the second electrode layer 14 are laminated in the mentioned order on an insulator layer 11 which is strong enough to serve as a substrate. A lamination thus formed is coated at the whole of the outer surface thereof with a porous protective layer 15 to obtain a membrane-covered type oxygen sensor. The first heater layer 19a is inserted between an upper insulator layer 11a and a lower insulator layer 11b, and the second heater layer 19b between the lower insulator layer 11b and the protective layer 15. When an electric current is applied to the heater layers 19a, 19b in a case where the temperature of an exhaust gas and oxygen sensor are low or at the time of starting an automobile engine, the temperature of the oxygen sensor can be increased rapidly. This allows an air/fuel ratio at the time of starting the engine to be controlled.
SONE KIMITAKE
IKEZAWA KENJI
