Ngk Spark Plug Company, Limited

Ngk Spark Co., Ltd.

Noboru Ishida

Takafumi Oshima

Yoshikuni Sato

Norihiko Nadanami

Satoshi Sugaya

Hideki Ishikawa

Masashi Ando

Mitsuyoshi Kawamura

Masaya Ito

Keigo Banno

Takaya Yoshikawa

Ryuji Inoue

Tomonori Kondo

Tatsuo Okumura

Masaya Watanabe

Takaki Otsuka

Shoji Kitanoya

Takeshi Morita

Yasuhisa Kuzuya

Masashi Sakamoto

Kenji Kato

Tetsuo Yamada

Yasushi Sato

Hiroki Fujita

Takaki Ootuka

Hiroshi Inagaki

Masato Taniguchi

Shigeru Miyata

Kentaro Mori

Nobuhiro Hayakawa

Hitoshi Yokoi

Toshitaka Matsuura

Shunichi Takagi

Seiji Mori

Hiroki Nakajima

Tessho Yamada

Shiro Kakimoto

Tomohiro Tajima

Yoshiro Noda

Masataka Taguchi

Tooru Matsuura

Shigeaki Akao

Tadashi Hattori

Osamu Suzuki

Junji Kawai

Hiroyuki Nishiyama

Toshiyuki Ishihara

Koichi Imaeda

Norio Kato

Atsushi Satsuma

Koichi Fujita

Katsuya Otake

Morio Onoda

Kenji Hayashi

Shinji Tanabe

A sensor control apparatus () includes a full-range gas sensor composed of an oxygen concentration detection cell having a pair of electrodes () and an oxygen pump cell having a pair of electrodes (). In an electric circuit section (), an Ip current flowing between the electrodes () is controlled such that an electromotive force Vs produced between the electrodes () becomes equal to a reference voltage. The reference voltage is usually set to a first reference voltage. However, when the subject gas is air, the reference voltage is set to a second reference voltage. Humidity of the subject gas is detected on the basis of an error &#x394;Ip between an Ip current detected when the reference voltage is set to the first reference voltage, and an Ip current detected when the reference voltage is set to the second reference voltage.

Gas-concentration/humidity detection apparatus

A sensor comprising a sensor element, a metallic housing holding therewithin the sensor element, an inner tubular member fixed to an axially rearward end of the metallic housing, and an outer tubular member radially surrounding the inner tubular member and having a radially inward crimping section for contact with an outer surface of the inner tubular member, wherein an axially forward end of the crimping section is disposed axially apart from an axially forward end of the outer tubular member by a distance of 1.5 mm or less.

Sensor

There is provided a gas sensor for measuring the concentration of a specific gas component in a gas under measurement, including a gas diffusion rate limiting portion, a measurement chamber communicating with an atmosphere of the gas under measurement through the gas diffusion rate limiting portion, a sensor element having an ion-conductive layer with first and second surfaces, a first electrode disposed in contact with the first surface of the ion-conductive layer within the measurement chamber and a second electrode disposed in contact with the second surface of the ion-conductive layer and communicating exclusively with the atmosphere of the gas under measurement and a cylindrical support member installing therein the sensor element with the first and second surfaces of the ion-conductive layer directed toward front and base end sides of the support member, respectively.

Gas sensor

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 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 gas sensor () including a measurement chamber () into which a gas GS is flown and a detection element main body () facing the measurement chamber (). The detection element main body () includes an element caseand a protective film () is adhered to a bottom surface thereof. An acoustic matching plate () and a piezoelectric element () of a substantially columnar shape and a tube body () provided in a position surrounding the acoustic matching plateand the piezoelectric elementare housed in the element case (). A filler is then introduced into the element case (), whereby the acoustic matching plate (), the piezoelectric element (), and the tube body () are sealed by a filled layer ().

A detecting-element assembly () is configured such that a piezoelectric element () is housed in a casing body portion () of a casing (), and is attached to a housing portion () of a flow path formation member () via a flange portion (). Therefore, the path between the piezoelectric element () and the position of attachment of the detecting-element assembly () is elongated, whereby ultrasonic waves which leak into the interior of the detecting-element assembly () from the piezoelectric element () become unlikely to reflectively return from a joint. Thus, the influence of, for example, noise stemming from reflected waves is reduced, thereby enhancing the accuracy of detection. An average clearance of 1 millimeter or more is provided along the outer circumferential surface of the casing body portion () of the detecting-element assembly (), whereby a problem of collected foreign matter is unlikely to occur.

Sensor and method for manufacturing the same

A method for detecting the concentration of a specific component in gas discharged from an internal combustion engine, which includes detecting the concentration of the specific component under certain driving conditions to determine a zero point, which indicates a zero concentration of the specific component, of the detection output; calibrating the detection output of the gas sensor based on the determined zero point; and detecting the concentration of the specific component in exhaust gas based on the calibrated detection output.

Methods and apparatus for measuring NOx gas concentration, for detecting exhaust gas concentration and for calibrating and controlling gas sensor

A hydrogen gas sensor is configured such that an O-ringis disposed within a measurement chamberin order to seal against a first support elementand against a proton conduction layerThis O-ringassumes the form of a rectangular frame that surrounds a first electrodeand a substantially circular cross section, and is elastic, heat resistant, and durable. A first metal plateand a second metal plateare disposed from the outside on opposite support elementsand, respectively. The hydrogen gas sensor of the present embodiment has a pair of right-hand and left-hand through-holesformed therein so as to extend along the thickness direction thereof. Boltsare inserted into the corresponding through-holesBy fastening the metal platesandfrom the outside by means of the boltsand nutsthe opposite support elementsandare fastened, thereby clamping the entire hydrogen sensor in a unitary condition.

A gas concentration sensor includes a measurement chamber for measuring a concentration of a specific gas component in a gas under measurement; an inflow path for allowing inflow of the gas under measurement thereinto and an outflow path for allowing outflow of the gas under measurement therefrom; a reflection wall for reflecting an acoustic wave; and an acoustic wave transmitting-receiving element having a transmitting-receiving surface adapted to transmit an acoustic wave toward the reflection wall and receive an acoustic wave reflected from the reflection wall. The concentration of the specific gas in the gas under measurement is detected on the basis of a propagation time between transmission of the acoustic wave and reception of the reflected acoustic wave. When a predetermined member having the sensor attached thereto is placed in a horizontal plane, the transmitting-receiving surface faces downward. A recess is formed in a peripheral portion of the reflection wall. The recess is receded toward a back surface of the reflection wall, namely, in a direction away from the transmitting-receiving surface.

Gas concentration sensor

A gas sensor includes an element casewith an internal peripheral surface formed as a taper surface. A portion of a housing sectionsurrounded by the taper surfaceand a protective filmis filled with a filler. When the fillerthermally expands at high temperature, the filleris subjected to a component of force in an upward direction by the taper surface. Therefore, projection of an element portioninvolving deformation of the protective filmis suppressed, a change &#x394;L of a propagation distance L to a reflecting sectionis also suppressed, and a detection accuracy never decreases. In addition, reverberation is reduced.

Gas sensor and gas concentration detecting device

An ultrasonic-wave propagation-time measuring method and gas concentration sensor are disclosed in which a reception wave which has been transmitted and received by an ultrasonic elementis subjected to full-wave rectification in order to obtain a full-wave-rectified wave, which is then integrated by an integration circuitto obtain an integral value. A peak value of the integral value is held by a peak-hold circuit. As to detection of gas concentration, a threshold-level calculation sectionsets a reference value on the basis of the peak value, and a point in time when the amplitude of a reception wave having undergone full-wave rectification is judged by a comparatorto have reached the reference value is regarded as an arrival time. Subsequently, a gas concentration is determined on the basis of a period between the emission time and the arrival time.

Ultrasonic-wave propagation-time measuring method and gas concentration sensor

A humidity sensor including an insulating substrate, and a lower electrode formed from a noble metal, a moisture sensitive layer formed of a porous body predominantly containing alumina and containing predetermined amounts of TiOand SnOand an upper electrode formed of a noble metal porous body successively formed on the insulating substrate. The upper electrode is connected to the moisture sensitive layer and a portion of the insulating substrate. Preferably, the lower electrode is formed of a porous body. More preferably, the lower and upper electrodes are formed from Pt. Furthermore, preferably, a heater and a temperature measurement resistor are provided in the insulating substrate and are located directly below the moisture sensitive layer.

Humidity sensor

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Gifu, Japan

Noboru Ishida