Ngk Spark Plug Company, Limited

Ryuji Inoue

Takafumi Oshima

Shoji Kitanoya

Norihiko Nadanami

Tomohiro Fuma

Kenji Kato

Noboru Ishida

Tomonori Kondo

Hiroki Fujita

Masaya Watanabe

Satoshi Sugaya

Takeshi Mitsuoka

Takio Kojima

Masahito Kida

Youichi Hattori

Shinsuke Ito

Norobu Ishida

Hitoshi Yokoi

Shiro Kakimoto

Tadashi Hattori

Hiroyuki Nishiyama

Koichi Imaeda

Taku Hirano

Atsushi Satsuma

Koichi Fujita

Shogo Hamatani

Takashi Hibino

Yumi Mizutani

Yumi Kuroki

There is provided a combustible gas detection apparatus with a gas sensor and a control device. The gas sensor includes first and second heating resistors each having a resistance that changes depending on a combustible gas concentration of gas under measurement. The control device includes an energization control section that alternately energizes the first and second heating resistors, a first calculation section that calculates a first calculation value responsive to the combustible gas concentration based on a voltage across the first heating resistor during energization of the first heating resistor, a second calculation section that calculates a second calculation value responsive to the combustible gas concentration based on a voltage across the second heating resistor during energization of the second heating resistor, and an anomaly judgment section that judges the occurrence of an anomaly in the first heating resistor by comparison of the first and second calculation values.

Combustible gas detection apparatus and combustible gas sensor control method

A relay includes: a pair of fixed terminals, each being arranged to have a fixed contact on a one-end face; a movable contact member arranged to have a pair of movable contacts that are correspondingly opposed to the respective fixed contacts; and a driving structure operated to move the movable contact member. In a moving direction of the movable contact member, a side where the fixed contacts are located is called a first side, and a side where the movable contacts are located is called a second side. The movable contact member includes: a center section located between the pair of movable contacts and located on the second side relative to the movable contacts; and a pair of extended sections located between the center section and the pair of movable contacts and extended in a direction including a component of the moving direction. At least one of the pair of extended sections has a specific relationship of being overlapped at least partly with the one-end face located on same side relative to the center section in vertical projection of the relay onto a predetermined plane perpendicular to the moving direction.

Relay

A relay includes: a plurality of fixed terminals arranged to have fixed contacts; and a movable contact member arranged to have a plurality of movable contacts that are correspondingly opposed to the respective fixed contacts. The relay further includes: a driving structure operated to move the movable contact member such that the respective movable contacts come into contact with the corresponding fixed contacts; a plurality of first vessels provided corresponding to the respective fixed terminals and arranged to have insulating property; a second vessel joined with the plurality of first vessels; and an air-tight space formed by the plurality of fixed terminals, the plurality of first vessels and the second vessel to allow the movable contact member and the respective fixed contacts to be placed therein.

In apparatus and method for detecting a combustible gas within an atmosphere to be detected, a calculated humidity deviation corresponding to a past gas concentration stored in a memory unit of a microcomputer is calculated on the basis of a correlation between a preset gas concentration of the combustible gas and the calculated humidity deviation, a calculated humidity of the atmosphere to be detected is corrected using the calculated humidity deviation to calculate a corrected humidity, and, when a concentration of the combustible gas is calculated on the basis of a terminal voltage, a temperature of the atmosphere to be detected, and a humidity of the atmosphere to be detected, the calculated corrected humidity is used for the humidity of the atmosphere to be detected calculated on the basis of terminal voltages across first and second heating resistors and the temperature of the detected temperature.

Apparatus and method for detecting combustible gas within atmosphere to be detected

In an ammonia sensor (), lead portions () and () are provided on an insulating substrate (); a pair of comb-shaped electrodes () and () are connected to the lead portions () and (), respectively; a sensitive layer () is provided on the comb-shaped electrodes () and (); and a protective layer () is provided on the sensitive layer (). Particularly, the sensitive layer () is formed of a gas-sensitive raw material predominantly containing ZrOand containing at least W in an amount of 2 to 40 wt. % as reduced to WO.

Ammonia sensor

This invention provides a gas sensor including a proton-conductive polymer electrolyte layer and a method for measuring gas concentration, that are capable of measuring gas concentration at high accuracy notwithstanding the presence of water vapor.

Gas sensor and method for measuring gas concentration using the same

A hydrogen gas sensor capable of accurately measuring hydrogen concentration of a measurement gas atmosphere in the presence of a variety of interfering gasses such as HO and CO. In the hydrogen gas sensor, the flow sectional area of a diffusion-rate limiting portionis rendered small; the electrode surfaces of first and second electrodesandare rendered large; and/or a solution containing a polymer electrolyte which may be identical to that of a proton-conductive layeris applied onto the surfaces of the first and second electrodesandto thereby form a layer containing the polymer electrolyte. Thus, the rate of conduction of protons from the first electrodeto the second electrodebecomes greater than the rate at which protons are derived from hydrogen which is introduced onto the first electrodevia the diffusion-rate limiting portion

Hydrogen gas sensor

A humidity-sensitive porous layer () of a humidity-sensitive element section () of a humidity sensor () is formed of a crystalline phase oxide grains such as AlO&#x2014;SnO&#x2014;TiOand of a glass phase such as silicate glass covering the crystalline phase. The glass phase contains an alkali metal oxide and/or alkaline earth metal oxide such as LiO. The humidity sensitive porous layer () assumes a skeletal structure that is formed of crystalline phase oxide grains covered or coated with the glass phase. A heater () of the humidity sensor is controlled to heat the humidity-sensitive element section () at a temperature ranging from 500&#xb0; C. to 800&#xb0; C. so as to clean off the humidity-sensitive element section while an internal combustion engine is running and exhausting fouling substances. Measurement of Humidity in an exhaust gas exhausted from an exhaust gas purifying apparatus of an internal combustion engine is carried out by using the humidity sensor (), so long as the exhaust gas temperature does not exceed 100&#xb0; C. regardless of whether or not the engine is running.

Humidity sensor and method of using the humidity sensor

A hydrogen sensor includes a first electrodeand a second electrodeprovided in contact with a proton conduction layer; a gas diffusion controlling portionprovided between a measurement gas atmosphere and the first electrode; and a support element () for supporting the proton conduction layer, the first electrode, the second electrode, and the gas diffusion controlling portion. Hydrogen contained in a measurement gas introduced via the gas diffusion controlling portionis dissociated, decomposed, or reacted by applying a voltage between the first electrodeand the second electrodeto thereby generate protons. Hydrogen concentration is obtained on the basis of a limiting current generated as a result of the generated protons being pumped out via the proton conduction layerfrom the first electrodeside of the proton conduction layer to the second electrodeside of the proton conduction layer. Hydrogen concentration on the first electrodeis controlled to a partial pressure of not less than 10atm, or more preferably, of not less than 3&#xd7;10atm and of less than 10atm.

Hydrogen sensor

A CO sensor and a CO-concentration measurement method which enables accurate measurement of CO concentration irrespective of the hydrogen concentration of a gas under measurement. By applying a first predetermined voltage between first and second electrodes and , hydrogen contained in a gas under measurement which has been introduced into a first measurement space via a first diffusion-controlling section dissociates, decomposes, or reacts with another element to generate protons. The thus-generated protons are transported from the first electrode to the second electrode via a first proton-conductive layer or protons are transported from the second electrode to the first electrode via the first proton-conductive layer (when the hydrogen concentration of the measurement gas is extremely low), so that the hydrogen concentration within the first measurement space is controlled to a constant level. The gas under measurement having a controlled hydrogen concentration is introduced into a second measurement space via a second diffusion-controlling section , and a second predetermined voltage is applied between third and fourth electrodes and . The CO concentration of the gas under measurement is obtained based on current (a limiting proton current) which flows between the third and fourth electrodes and . Alternatively, the CO concentration of the gas under measurement is obtained from electromotive force generated between the third and fourth electrodes and

CO sensor and method of measuring CO concentration

A hydrogen gas sensor capable of accurately measuring hydrogen concentration of a measurement gas atmosphere in the presence of a variety of interfering gasses such as H O and CO. In the hydrogen gas sensor, the flow sectional area of a diffusion-rate limiting portion is rendered small; the electrode surfaces of first and second electrodes and are rendered large; and/or a solution containing a polymer electrolyte which may be identical to that of a proton-conductive layer is applied onto the surfaces of the first and second electrodes and to thereby form a layer containing the polymer electrolyte. Thus, the rate of conduction of protons from the first electrode to the second electrode becomes greater than the rate at which protons are derived from hydrogen which is introduced onto the first electrode via the diffusion-rate limiting portion

A method of manufacturing a gas sensor, including a substrate electrode layer forming step, and a surface electrode layer forming step. The gas sensor includes first and second processing spaces, an oxygen concentration detection element, an oxygen pumping element, an oxidation catalyst and a combustible gas component concentration detection element.

Method of manufacturing a gas sensor

A device and method for measuring combustible-gas concentration and a device and method for measuring hydrocarbon-gas concentration, which exhibit low dependence on oxygen concentration variations as well as low temperature dependence. Paste is applied to the inner surface of a closed-bottom cylindrical solid electrolyte element, thereby forming a layer serving as a reference electrode. Plating with platinum is performed, so as to form a layer serving as a first detection electrode, on the outer surface of the solid electrolyte element only at a portion extending from an end portion of the solid electrolyte element to the vicinity of the interface between a heating resistor and a heating-resistor lead portion, which are formed within a heater element contained in the cylindrical solid electrolyte element. Paste which contains gold powder and 10 parts of indium oxide is applied onto the platinum-plating layer so as to form a layer serving as a second detection electrode, followed by firing. Subsequently, a diffusion layer containing spinel is formed by thermal spraying on the surface of a detection electrode. The heater element is disposed in the solid electrolyte element such that an end portion abuts an inner bottom portion of the solid electrolyte element. Lead wires for measuring internal resistance, which extend from the reference electrodes, and a lead wire extending from the detection electrode are connected to a temperature controller.

Device for measuring combustible-gas concentration in an exhaust gas

A gas sensor which can detect the concentration of a combustible gas component in a measurement gas with high accuracy even when the oxygen concentration of the measurement gas or the element temperature changes and which has an excellent response in detecting the combustible gas component is disclosed. In a gas sensor , the oxygen concentration of a measurement gas is adjusted to a predetermined level within a first processing space through operation of a first oxygen pump element . The measurement gas having an adjusted oxygen concentration is then introduced into a second processing space , where a combustible gas component is burned through the assistance of electrodes and functioning as oxidation catalyst sections. Constant voltage is applied to a combustible gas component concentration detection element . In this state, when the amount of oxygen changes due to the combustion of the combustible gas component, the output current of the combustible gas component concentration detection element changes with change in the amount of oxygen. Therefore, information regarding the combustible gas component concentration of the original measurement gas can be obtained from the value of the output current. Further, oxygen required to burn the combustible gas component within the second processing space is supplemented by a second oxygen pump element . Unlike conventional apparatuses, no feedback system is used, and a variation in the concentration of the combustible gas component appears directly as a variation in the current of the combustible gas component concentration detection element . Therefore, a high detection response is obtained.

Gas sensor, method of manufacturing the same, and gas sensor system using the gas sensor

A gas sensor comprising a proton-conductive layer formed of a polymer electrolyte; first and second electrodes and disposed in contact with the proton-conductive layer and having a function of dissociating hydrogen; a gas-diffusion-rate limiting layer disposed between a measurement gas atmosphere and the first electrode and adapted to diffuse the gas under measurement to the first electrode in a diffusion-rate limited state; and a dense support supporting these elements. Hydrogen gas having reached the first electrode via the gas-diffusion-rate limiting layer is dissociated into protons by virtue of the catalytic action of Pt contained in the electrode and the voltage applied to the first electrode , and the generated protons are pumped to the second electrode via the proton-conductive layer and are converted to hydrogen gas, which diffuses into the measurement gas atmosphere. When the applied voltage is sufficiently high, saturation current flows between the first and second electrodes and , and the magnitude of the saturation current varies in proportion to the hydrogen gas concentration of the gas under measurement. A hydrogen gas sensor which operates at low temperature in a hydrogen-rich atmosphere, and which can accurately measure hydrogen gas concentration of a fuel gas of a fuel cell, is thereby provided.

Growing community of inventors

Gifu, Japan

Ryuji Inoue