Ngk Spark Plug Company, Limited

Hideki Ishikawa

Noboru Ishida

Yoshikuni Sato

Takafumi Oshima

Keigo Banno

Takeshi Morita

Masashi Sakamoto

Nobuyuki Hotta

Hideki Uematsu

Hiroya Ishikawa

Yasushi Sato

Shoji Kitanoya

Takeshi Ohno

Takafumi Shichida

Masashi Tsuzuki

Shunsuke Tsuga

Hiroaki Yagi

Shunta Ohashi

Kenji Miyabata

Yasuki Izutsu

Katsuya Otake

Morio Onoda

A fuel cell stack including a plurality of electricity generation units fastened by means of a plurality of fastening members. Each electricity generation unit includes a single cell, and a sealing member sandwiched between two other members thereby sealing one of the anode chamber and the cathode chamber. The surface of the sealing member included in at least one electricity generation units, the surface facing either of the two other members, has a surface roughness Ra of 3.0 &#x3bc;m or less.

Fuel cell stack and method for manufacturing fuel cell stack

The fuel cell includes a fuel cell stack in which a plurality of planar power generation cells are stacked in a thickness direction thereof. The fuel cell also includes a heat exchanger provided between the two adjacent power generation cells in the stacking direction and in contact with the power generation cells, and including an internal first flow path that passes the oxidant gas or fuel gas supplied from outside. The fuel cell also includes a second flow path connected to an outlet side of the first flow path of the heat exchanger and to the cathode side or the anode side of each of the power generation cells, and supplying the oxidant gas or fuel gas that has passed through the first flow path to the cathode side or anode side of each of the power generation cells on both sides in the stacking direction of the heat exchanger.

Fuel cell

A fuel cell according to one mode includes a plurality of stacked cell units, each cell unit including at least an electrically conductive interconnector having a front surface and a back surface; a pair of connection members which are electrically connected to the interconnector; a single cell which includes an anode, a cathode, and an electrolyte therebetween and which is electrically connected to the connection members; and a separator having an opening which is connected to an outer peripheral portion of the single cell, the cell units being clamped together in a stacking direction, wherein the connection member on an anode side or a cathode side of the single cell of at least one cell unit of the cell units has a thickness different from that of the connection member on the anode side or the cathode side of the single cell of another cell unit.

Fuel cell comprising connection members having different thickness for each of cell units and method for manufacturing same

A fuel cell includes a main body which is formed by stacking a cathode layer, an electrolyte layer, and an anode layer, in which the surface of one of the cathode and anode layers serves as a first main surface, and the surface of the other layer serves as a second main surface; a first current collector in contact with the first main surface; and a second current collector in contact with the second main surface. As viewed in a thickness direction, at least a portion of the boundary of a second region of the second current collector corresponding to the second main surface is located within a first region of the first current collector corresponding to the first main surface, and the remaining portion is located within the first region or on the boundary of the first region.

A multilayer piezoelectric element includes at least one piezoelectric layer unit having sintered piezoelectric ceramic and electrode layers alternately stacked together in a first direction and a positioning member that, when the at least one piezoelectric layer unit is placed in an enclosing member in such a manner that the enclosing member encloses therewith a periphery of the at least one piezoelectric layer unit along a second direction perpendicular to the first direction, controls the position of the at least one piezoelectric layer unit within the enclosing member along the second direction.

Multilayer piezoelectric element, fuel injector having the piezoelectric element and piezoelectric element production method

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

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 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

The present invention provides a method and apparatus using a gas concentration sensor for accurately controlling an air fuel ratio in an internal combustion engine, featuring in that before the fuel-vaporized gas purged from the canister enters into the intake manifold whereat the sensor detects the gas concentration of the purged gas, the sensor is adjusted so as to adjust a zero point (or zero output level) of the sensor output. In step of FIG. , a judgment is made as to whether the flow rate of air reaches a predetermined level. In step , processing for zero-point correction of the gas concentration sensor is performed. Specifically, in a state in which the purge valve is closed, concentration of purge gas is measured by use of the gas concentration sensor , and a sensor output S at that time is obtained. Subsequently, the sensor output S is compared with a correct sensor output S in order to obtain a difference &Dgr;S therebetween. Accordingly, during subsequent gas concentration measurement, a value S obtained through subtraction of the difference &Dgr;S from an obtained sensor output S is used as a correct sensor output. In step , a supply amount of purge gas, i.e., a concentration of the purge gas to be supplied is obtained. In subsequent step , the purge valve is driven in order to supply purge gas to the intake pipe in a required amount (A%).

Method and apparatus using a gas concentration sensor for accurately controlling an air fuel ratio in an internal combustion engine

An ultrasonic-wave propagation time measuring method which enables determination of accurate propagation time, a gas-pressure measuring method, a gas-flow-rate measuring method, and a gas sensor. A reception wave which has been transmitted and received by an ultrasonic element is shaped and integrated by an integration circuit to 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 resistance-voltage-division circuit sets a reference value on the basis of the peak value, and a point in time when the integral value of the reception wave is judged by a comparator to have reached the reference value is regarded as an arrival time. Subsequently, a gas concentration is detected on the basis of a period between the emission time and the arrival time. As to detection of gas pressure and flow rate, the gas pressure is detected on the basis of the peak value, and further, the gas flow rate is calculated on the basis of the gas pressure.

Ultrasonic-wave propagation-time measuring method, gas-pressure measuring method, gas-flow rate measuring method, and gas sensor

When a sensor has deteriorated, the propagation time T &prime; of a first reflection wave becomes greater than the propagation time T of a first reflection wave as measured in a new sensor. If measurement of the concentration of a specific gas is based on the propagation time T of the first reflection wave as measured in the new sensor, gas concentration cannot be determined accurately. By contrast, a reflection wave other than the first reflection wave (for example, a second reflection wave) is merely reflected off the surface of the ultrasonic element and is not affected by the internal structure of the ultrasonic element. Therefore, even when the sensor is deteriorated, the propagation time T T &prime; of the second reflection wave exhibits less variation and is less susceptible to deterioration of the sensor. Therefore, the concentration of a specific gas is determined on the basis of the propagation time of the second reflection wave, which is less susceptible to deterioration of the sensor, instead of the propagation time of the first reflection wave, which is more susceptible to deterioration of the sensor. Thus, gas concentration can be measured accurately.

A gas concentration sensor comprises an ultrasonic element,opposite a reflection surface,A depression,is formed on an edge portion of a reflection surface,which is in contact with a side wall of a measurement chamber,such that a bottom surface of the depression,is substantially in parallel with the reflection surface,The distance between the ultrasonic element,and the edge portion of the reflection surface,becomes greater than the distance between the ultrasonic element,and a central portion of the reflection surface,As a result, an indirect wave, which impinges obliquely on the side wall of the measurement chamber,and propagates along the side wall, is reflected from the bottom surface of the depression,and propagates. Thus, the propagation distance of this indirect wave becomes greater as compared to the case where the reflection surface,is flat, so that the indirect wave is not combined with a direct wave in the vicinity of a modulation point of the direct wave. That is, since the modulation point of the direct wave can be detected accurately, a time interval between a modulation point of a transmitted wave and that of a received wave can be measured as the propagation time of an ultrasonic wave, thereby enabling accurate determination of gas concentration.

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Aichi, Japan

Hideki Ishikawa