Ngk Spark Plug Company, Limited

Masahito Kida

Takio Kojima

Takafumi Oshima

Ryuji Inoue

Yoshihiro Nakano

Shinichi Nakagawa

Shoji Kitanoya

Tomohiro Fuma

Yoshinori Tsujimura

Koichi Ikawa

Koichi Fujita

Masahiro Takakura

Shinichiro Kito

Takashi Hibino

Yumi Mizutani

Between a gas sensing layer () and a base member () composed of a silicon substrate () and an insulating coat layer (), there is formed an adhesion layer, to improve the adhesion therebetween, and to prevent separation. The gas sensing layer () and sensing electrodes () are electrically connected by abutment of a confronting surface () of sensing electrodes () confronting the gas sensing layer () and sides surfaces of the sensing electrodes on both sides, on the gas sensing layer (), and accordingly the gas sensor properly senses an electric characteristic of the gas sensing layer () varied in accordance with a concentration variation of a specified gas. Furthermore, the sensing electrodes () are in contact with the gas sensing layer (), but the sensing electrodes are not in contact with the adhesion layer (). Therefore, the adhesion layer () need not be a complete insulating layer, and it is possible to use, as the adhesion layer, an incomplete insulating film or a conductive film, so that options of the adhesion layer () are increased.

Gas sensor

There is provided an oxidizing gas sensor that includes an insulating substrate, a gas sensing layer laminated on the insulating substrate and substantially made of tin oxide so as to make resistance changes in response to concentration variations in oxidizing gas and a plurality of catalyst grains applied to a surface of the gas sensing layer and substantially made of gold, wherein 20% or more of the catalyst grains have an aspect ratio of 2.0 or greater when viewed at from the surface of the gas sensing layer.

Oxidizing gas sensor and production method thereof

The present invention provides a gas sensor having excellent humidity resistance even if used in a high temperature and high humidity atmosphere. According to the present invention, a gas sensor is comprised of: a silicon substrate; a metal-oxide semiconductor portion comprised mainly of SnOand formed on the substrate; and a catalytic portion comprised of Pd and dispersed on a surface of the metal-oxide semiconductor portion, wherein the metal-oxide semiconductor portion and the catalytic portion constitute a gas sensing portion. Furthermore, an insulating portion comprised mainly of SiOis formed dispersedly on a surface of the gas sensing portion. Further, the catalytic portion and the insulating portion are formed on the surface of the metal-oxide semiconductor portion so that the surface additive rate, which is expressed by Si/(Pd+Si) representing the ratio in the number of atoms of Si to Pd, of the gas sensing portion having the insulating portion may be 65% or more to 97% or less, and so that the surface additive rate, which is expressed by Si/(Sn+Si) representing the ratio in the number of atoms of Si to Sn, of the gas sensing portion may be 75% or more to 97% or less.

The present invention provides an apparatus for measuring the concentration of a constituent to be detected in exhaust gas, which apparatus is capable of detecting with a high accuracy the concentration of the constituent to be detected in exhaust gas even though oxygen concentration in the exhaust gas varies. In an exhaust gas sensor 1 for use in the measuring apparatus, exhaust gas is introduced into spaces 15, 16 on both sides of an oxygen concentration cell element 4, and the oxidation catalyst activities of first to third electrodes 11 to 13 are adjusted so that there occurs a difference between the space 15 and the space 16 in consumption of the constituent to be detected, which consumption is caused by the oxidation of the constituent. Thus a concentration cell electromotive force is generated in the oxygen concentration cell element 4, and an oxygen pump element 3 pumps oxygen into or out of the space 15 so that the electromotive force is held at an target value EC not more than 10 mV. The pump current at this time is taken as the detection output on the constituent to be detected. The strengths of the oxygen concentration cell element 4 and of the oxygen pump element 3 can be increased by the provision of an integrated sintered body in which the elements 4 and 3 are laminated together with the space 15 formed between the first electrode 11 and the second electrode 12. Besides, the accuracy of detecting the constituent to be detected can be improved by the control over the temperature of the oxygen concentration cell element 4 and by the temperature compensation to the pump current.

Exhaust gas sensor and system thereof

There is described a gas-component concentration sensor, a method of using the sensor, and a method of manufacturing a particular electrode of the sensor, wherein the sensor comprises:

Method for manufacturing electrode

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Nagoya, Japan

Masahito Kida