Fuji Electric Co., Ltd.

Keisuke Sugimoto

Teizo Takahama

Yuji Sugiyama

Masahiko Masuda

Takeo Tanaka

Hideo Shiraishi

A limited current type oxygen sensor comprises an oxygen ion conductive solid electrolyte, a detection element including a positive electrode and a negative electrode, and a heater element including a heater. The negative electrode is installed on one of the walls constituting a space communicating with a small hole for restricting the amount of oxygen to diffuse therethrough. The porous positive electrode and the heater are embedded in the oxygen ion conductive solid electrolyte layers.

Oxygen sensor

A limited current type oxygen sensor comprises a solid electrolyte element formed from material having high oxygen-ion conductivity such as yittria-stabilized zirconia. Electrodes are provided on the top surface and the bottom surface of the element and are formed by calcining a mixture of small ceramic particles that are relatively sinter-retardant as compared with oxygen-ion conducting ceramics, of 200 .ANG. in average particle size fine precious metal particles, and a binder. A cover is provided over the second electrode and the cover includes at least one diffusion orifice that permits ambient gas to diffuse toward the second electrode. The dry-gas-based and humid-gas-based oxygen content of the gas is determined by applying a first voltage less than the theoretical water decomposition voltage and a second voltage greater than the theoretical water decomposition voltage to the electrodes to generate corresponding currents associated with the oxygen-ions which flow through the electrolyte element between the first electrode and the second electrode. A heater may be buried in the electrolyte element to increase the flow rate of oxygen ions between the electrodes.

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Kanagawa, Japan

Keisuke Sugimoto