Nippon Soken, Inc.

Denso Corporation

Nippondenso Co., Ltd.

Other

Toyota Jidosha Kabushiki Kaisha

Daisuke Makino

Keigo Mizutani

Satoshi Nakamura

Toshiyuki Kawai

Kaoru Kuzuoka

Itsuhei Ogata

Mitsunobu Uchida

Hiroo Imamura

Masataka Naito

Eiichi Kurokawa

Takashi Kojima

Toshitaka Saito

Hidetoshi Kato

Masahiro Shibata

Kazunori Suzuki

Masanori Yamada

Toshihiro Sakawa

Atsushi Kurano

Torahiko Sasaki

Hisayoshi Ohta

Eturo Yasuda

Masahiro Taguchi

Hiromi Sano

Makoto Shirai

Kanehito Nakamura

Hiroshi Mori

Hirokatsu Mukai

Fumihiko Sato

Muneo Yorinaga

Hidetaka Hayashi

Yoshimasa Hijikata

Michiyasu Moritsugu

Takanao Tomura

Kengo Toguchi

Noriaki Kihara

Takumi Ushikubo

Masaru Yamada

Katsuya Hirai

Michihiro Wakimoto

Hideomi Kawachi

Methods of manufacturing a ceramic sheet and a gas sensing element are disclosed. At least ceramic powder, a binder and a plasticizer are blended and mixed in slurry. The slurry is formed into unfired green sheets, on which paste is printed. Each of the unfired green sheets has porosity greater than 5%. In the manufacturing methods, the unfired green sheets are pressurized with a pressure of 10 MPa at a temperature above 60&#xb0; C., after which the paste is printed on surfaces of the unfired green sheets. In the method of manufacturing the gas sensing element, a shielding layer, a porous diffusion resistance layer and the unfired green sheets for a sensing layer, a reference gas airspace forming layer and a heating layer are stacked to form a stacked ceramic body, whish is fired to obtain the gas sensing element.

Method of manufacturing ceramic sheet and method of manufacturing gas sensing element

A gas sensor is disclosed which attains high response speed, low power consumption, superior water splash resistance and a little setting direction dependency and setting angle dependency. In this gas sensor, a measured gas room is provided inside an inner cover, and gas passage holes for leading a measured gas in are provided on side surfaces of the inner cover and an outer cover. The gas passage holes provided on the outer cover are positioned much closer to a top end side than the gas passage hole provided closest to the top end side in the inner cover. Partitions disposed extendedly in an axial direction of the gas sensor are provided between the outer cover and the inner cover.

Gas sensor

A gas sensor element is provided which is designed to measure the concentration of hydrogen-containing gas accurately. The sensor element includes an oxygen pump cell working to keep the concentration of oxygen contained in measurement gasses entering a measurement gas chamber at a low concentration level and a hydrogen-containing gas measurement cell. The hydrogen-containing gas measurement cell is made up of a proton-conductive solid electrolyte body and a first and a second gas measurement electrode affixed to the proton-conductive solid electrolyte body. The first gas measurement electrode is exposed to the measurement gas chamber and serves to produce a signal between the first and second gas measurement electrodes as a function of the concentration of the hydrogen-containing gas.

Hydrogen-containing gas measurement sensor element and measuring method using same

A fault detecting apparatus for a gas concentration sensor is provided. The apparatus includes a storage device and a fault detecting circuit. The storage device stores therein fault detectable conditions in which preselected different types of faults of the gas concentration sensor are allowed to be detected, respectively. The fault detecting circuit works to detect a selected one of the faults stored in said storage device. When one of the fault detectable conditions is encountered during operation of the gas concentration sensor, the fault detecting circuit initiates detection of a corresponding one of the faults based on an output of the gas concentration sensor, thereby enabling the fault detecting circuit to identify the type of one of the faults to be detected correctly.

Fault detecting apparatus designed to detect different types of faults of gas sensor

An air-fuel ratio sensor includes a sensor element inserted through a cylindrical housing for detecting an air-fuel ratio in an atmosphere of unburnt gas, and a measured gas side cover disposed on an end of the cylindrical housing so as to cover the sensor element and defining an inside chamber for storing therein a gas to be measured. The cover has a nested structure composed of a plurality of cup-shaped cover members disposed one inside another, each cover member having a gas inlet hole formed in a side wall thereof and a bottom hole formed in a bottom wall thereof. The gas inlet hole of an innermost one of the plural cover members that directly faces the sensor element is offset from an air-fuel ratio detecting portion of the sensor element toward the housing in an axial direction of the sensor.

Air-fuel ratio sensor

A gas sensor includes a measurement gas chamber into which a measurement gas is introduced. An oxygen pumping cell adjusts an oxygen concentration in the measurement gas chamber. An oxygen monitor cell has a monitor electrode exposed in the measurement gas chamber. The monitor electrode has an oxidizing activity with respect to a specific component of the measurement gas. A sensor cell has a sensor electrode exposed in the measurement gas chamber. The sensor electrode has an oxidizing activity with respect to the specific component of the measurement gas which is lower than the oxidizing activity of the monitor electrode. An oxygen-ion current in the oxygen monitor cell is detected. An oxygen-ion current in the sensor cell is detected. A concentration of the specific component of the measurement gas is detected from a relation between the detected oxygen-ion currents in the oxygen monitor cell and the sensor cell.

Gas sensor and method of detecting gas concentration

A highly accurate reduction resistant thermistor exhibiting stable resistance characteristics even under conditions where the inside of a metal case of a temperature sensor becomes a reducing atmosphere, wherein when producing the thermistor comprised of a mixed sintered body (M1 M2)O.AO, the mean particle size of the thermistor material containing the metal oxide, obtained by heat treating, mixing, and pulverizing the starting materials, is made smaller than 1.0 &#x3bc;m and the sintered particle size of the mixed sintered body, obtained by shaping and firing this thermistor material, is made 3 &#x3bc;m to 20 &#x3bc;m so as to reduce the grain boundaries where migration of oxygen occurs, suppress migration of oxygen, and improve the reduction resistance.

Reduction resistant thermistor, method of production thereof, and temperature sensor

Thermistor elements composed mainly of a metal oxide sintered body are prepared by mixing a metal oxide precursor in a liquid phase to prepare a solution or slurry of the precursor. The precursor solution or slurry is sprayed to form droplet particles which are heat treated to form a thermistor raw material powder which powder is then molded and sintered into a shape to provide a metal oxide sintered body.

Method of producing thermistor element and production apparatus for production apparatus for producing raw materials for thermistor element

A gas sensor consists of a pump cell, a monitor cell, and a sensor cell. The sensor cell is supplied with power to produce a sensor cell current. The monitor cell is supplied with power to produce a monitor cell current. A sensor cell and a monitor cell current detector are disposed between a sensor cell electrode exposed to a gas cavity and a sensor cell power supply and between a monitor cell electrode exposed to the gas cavity and a monitor cell power supply, thereby enabling the sensor cell current and the monitor cell current to be measured without addition of electric noises arising from current components flowing from the monitor cell to the sensor cell and vice versa.

Structure of gas sensor designed to minimize error of sensor output

This invention provides a reducing-atmosphere-resistant thermistor element, the resistance of which does not greatly change even when the element is exposed to a reducing atmosphere, and which has high accuracy and exhibits excellent resistance value stability. The thermistor element has a construction in which an oxygen occlusion-release composition, having oxygen occlusion-release characteristics, such as CeO is dispersed in a composition containing a mixed sintered body (M1 M2)O .AO as a principal component. The oxygen occlusion-release composition emits absorbed oxygen in a reducing atmosphere and suppresses migration of oxygen from the composition constituting the element. Therefore, the resistance value does not greatly change even when the element is exposed to a reducing atmosphere, and the element can accurately detect the temperature for a long time. The present invention can thus provide a temperature sensor having high reliability.

Reducing-atmosphere-resistant thermistor element, production method thereof and temperature sensor

An objective gas is successively introduced into first and second chambers which are connected via a narrow passage. A first monitor cell, provided on a surface of the first chamber, generates an electromotive force representing an oxygen concentration in the first chamber. A second monitor cell, provided on a surface of the second chamber, generates an electromotive force representing an oxygen concentration in the second chamber. A voltage applied to a pump cell is controlled based on the electromotive forces obtained from the first and second monitor cells.

Gas sensing element employable in an exhaust system of an internal combustion engine

A gas sensor has a housing, a gas sensing element held by the housing and having a gas contact portion and an element cover for covering the gas contact portion. The element cover has a double pipe structure formed by layering an outer pipe and an inner pipe. The outer pipe has an outer bottom portion having an outer bottom hole and an outer side portion having plural outer side holes. The inner pipe has an inner bottom portion having an inner bottom hole and an inner side portion having plural inner side holes disposed not to overlap the outer side holes. A spacing D of 0.2-1.0 mm is formed between the outer bottom portion and the inner bottom portion. As a result, flow resistance in the spacing D is relatively high, and the sample gas sufficiently and more smoothly flows toward the gas sensing element. Therefore, the element cover prevents condensed water from entering the inside of the gas sensor and improves response of the gas sensor.

Gas sensor for vehicle engine having a double-pipe cover

A gas concentration detecting device for detecting the concentration of a component, such as an oxygen in an exhaust gas of an internal combustion engine. The device has a concentration detecting body,for detecting the oxygen and a cover,of a double wall structure which is for encircling the portion of the detecting body opened to the flow of the exhaust gas to be detected. The cover,has, at its axial tip end wall, a plurality of holes,and,arranged in such a manner that one of the holes functions as a gas inlet hole and the other hole functions as a gas outlet hole in order to cause the gas to be smoothly ventilated. The cover has, at its side, a wall of a closed structure with no hole for the passage of the gas, which is effective for preventing the cover,and the detecting body,from being cooled by the exhaust gas, thereby enhancing a heat retaining capacity, thereby preventing particulates from being deposited.

Gas concentration detecting device

A gas concentration detector using solid electrolyte layers laminated measures a concentration of gas constituents in measuring gas such as exhaust gas of an internal combustion engine without being influenced by oxygen concentration in the measuring gas. The measuring gas is introduced into an inner cavity of the detector and outside air as a reference gas is introduced into an air passage in the detector. Oxygen concentration in the measuring gas in the inner cavity is maintained at a predetermined level by operation of an oxygen pumping cell constituted by an ion conductive solid electrolyte layer and a pair of electrodes formed on both surfaces of the layer. The oxygen concentration in the inner cavity is measured by an oxygen sensor cell having one electrode exposed to the inner cavity and the other electrode exposed to the reference gas. The concentration of the gas constituents in the measuring gas is measured in terms of ion current generated in a detector cell constituted by an ion conductive solid electrolyte layer and a pair of electrodes formed on both surfaces of the layer, one electrode being exposed to the measuring gas in the inner cavity and the other exposed to the reference gas in the air passage. Either one of the sensor cell and detector cell electrodes exposed to the measuring gas in the inner cavity is made of a material active to the gas constituents to be measured and the other electrode is made of a material inactive thereto.

Solid electrolyte gas concentration detector

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Ichinomiya, Japan

Daisuke Makino