Denso Corporation

Denso Corpora Tion

Yuusuke Toudou

Takehito Kimata

Yuusuke Kawamoto

Takashi Araki

Toru Katafuchi

Mitsunobu Nakatou

Tsunenobu Hori

Keigo Mizutani

Takashi Kojima

Kaoru Kuzuoka

Sotoo Takahashi

Tomohiro Adachi

Eriko Maeda

A gas sensor is equipped with a housing, an insulator retained by an inner periphery of the housing, a sensing device having a front end portion protruding from a front end surface of the insulator, and a protective cover which covers a front end portion of the sensing device. A pump electrode and a sensor electrode are disposed in a front end portion of the solid electrolyte body. The pump electrode is exposed to a measurement gas and regulates the concentration of oxygen in the measurement gas. The sensor electrode is exposed to the measurement gas and measures the concentration of a given gas component in the measurement gas after being regulated in concentration of oxygen by the pump electrode. A base end portion of the sensor electrode in a lengthwise direction is located closer to a base end side of the gas sensor than a front end surface of the housing is. This minimizes a variation in temperature of the sensor electrode and enhances the accuracy in measuring the concentration of the given gas component.

Gas sensor

A gas concentration detection apparatus is provided with a measuring gas chamber, a solid electrolyte body, a pump cell, a sensor cell, a pump cell controller and a sensor cell detection section. The pump cell controller applies an elimination voltage to the pump cell at a start-up point, before a gas concentration is detected. The water in the measuring gas chamber is decomposed and hydrogen is generated by application of the elimination voltage. Oxygen occluded in a sensor electrode of the sensor cell is removed by the hydrogen.

Gas concentration detection apparatus

A gas sensor includes a solid electrolyte, a gas chamber, a reference gas chamber, a pump cell, a monitor cell, and a sensor cell. The gas chamber has a spatial width Wconstant in a width direction W orthogonal to the direction of flow of a gas in a position where the pump electrode, the monitor electrode, and the sensor electrode are provided on the solid electrolyte. An amount of shift &#x394;Xof a central position Oof a gap S in the width direction W between the monitor electrode and the sensor electrode from a central position Oin the width direction of the pump electrode has relationship of &#x394;X&#x2264;&#xbc; Wwhere the pump electrode has a width W. In addition, positions &#x394;Yof a of a side surface of the monitor electrode and of a side surface of the sensor electrode from the central position Oin the width direction W of the pump electrode have relationship of &#x394;Y&#x2264;&#xbd; W

Gas sensor for detecting concentration of specific gas component

A gas sensor is equipped with a solid electrolyte body, a pump electrode, a sensor electrode, and a heater. In the gas sensor, a region of the whole of a front end portion of a heater base in which a heating element is disposed is broken down into three regions: an intermediate region defined between a front end and a base end of the sensor electrode, a front end region located closer to a front end side than the intermediate region is, and a base end region located closer to a base end side than the intermediate region is. A resistance value per unit area of a heating element lying in the base end region and a resistance value per unit area of the heating element lying in the front end region is selected to be higher than that of the heating element lying in the intermediate region, thereby keeping the temperature of a region around the sensor electrode at a desired level even when the temperature of gas changes.

A gas sensor device is equipped with the sensor cell, the pump cell, the inner void space, and the gas inlet. The sensor cell is created by a portion of the solid electrolyte body and a pair of sensor electrodes disposed on the solid electrolyte body. The pump cell is created by a portion of the solid electrolyte body and a pair of pump electrodes disposed on the solid electrolyte body. The inner void space faces the sensor electrode and the pump electrode. If a dimension of said gas inlet in a direction in which the measurement gas flows in the gas inlet is defined as L, a sectional area of the gas inlet taken perpendicular to the direction of flow of the measurement gas in the gas inlet is defined as S, a distance between the gas inlet and the sensor cell is defined as L, and a sectional area of the inner void space taken perpendicular to a direction in which the pump cell and the sensor cell are aligned with each other is defined as S, a relation of 1000&#x2264;(L/S)&#xd7;(L/S)&#x2264;5000 is met.

Gas sensor device

A sensor structural body, which is formed by stacking a sensor element and a heater, has a sensor protruding portion that protrudes distalward from a holder. The sensor element includes a solid electrolyte body, a measured-gas space, a reference-gas space, a pump cell, a monitor cell and a sensor cell. A heat-generating portion of the heater is entirely arranged in the sensor protruding portion. The length L (in mm) of a formation region of the heat-generating portion and the length H (in mm) of the sensor protruding portion in a longitudinal direction, in which the sensor protruding portion protrudes from the holder, are set to be in a range that is enclosed by first to fourth reference lines X, X, Xand Xon a two-dimensional coordinate plane whose horizontal and vertical axes respectively indicate the lengths L and H. The first to the fourth reference lines X-Xrespectively represent the relationships of H=L, H=20, H=&#x2212;4.24L+42.71 and H=&#x2212;4.24L+68.6.

A gas concentration measuring apparatus is provided which works to calculate the concentration of a given gas component with enhanced accuracy. The gas concentration measuring apparatusincludes, a gas sensorand a calculating portion. The gas sensoris equipped with a pump cell, a monitor cell, and a sensor cell. The calculating portionsubtracts a monitor cell current Im that is a current flowing through the monitor cellfrom a sensor cell current Is that is a current flowing through the sensor cellto calculate the concentration of the given gas component in gas g. When calculating the concentration of the given gas component, the calculating portionperforms a correction operation to bring a value of the monitor cell current Im close to a value of an oxygen dependent current Iso that is a component of the sensor cell current Is which arises from the concentration of oxygen.

Gas concentration measuring apparatus

A gas concentration measuring apparatus is provided which works to calculate the concentration of a given gas component with enhanced accuracy. The gas concentration measuring apparatusincludes, a gas sensorand a calculating portionThe gas sensoris equipped with a pump cella monitor celland a sensor cellThe calculating portionsubtracts a monitor cell current Im that is a current flowing through the monitor cellfrom a sensor cell current Is that is a current flowing through the sensor cellto calculate the concentration of the given gas component in gas g. When calculating the concentration of the given gas component, the calculating portionperforms a correction operation to bring a value of the monitor cell current Im close to a value of an oxygen dependent current Iso that is a component of the sensor cell current Is which arises from the concentration of oxygen.

The temperature sensor includes a thermo-sensitive element, first and second electrode wires electrically connected to the thermo-sensitive element, first and second signal wires partially overlapped with and connected to the first and second electrode wires, respectively. The first and second electrode wires are made of a first metal material consisting primarily of Pt. The first and second signal wires are made of a second metal material containing Al and having a linear thermal expansion coefficient larger than that of the first metal material. Each of an overlap portion of the first electrode wire and the first signal wire and an overlap portion of the second electrode wire and the second signal wire includes a junction part formed by melting and thereafter coagulating the first or second electrode wire and the first or second signal wire. The junction part includes an oxidation film containing Al formed on a surface thereof.

Temperature sensor

A temperature sensor has a temperature sensitive element for detecting a temperature, a sheath pin having core wires electrically connected to the temperature sensitive element, lead wires to output a detection signal of the temperature sensitive element to an outside device, connectors through which the core wires and the lead wires are connected, and a protection tube accommodating the core wires, the lead wires and the connectors. The protection tube has a supporting member made of an elastic member having inserting and supporting holes through which the connectors are inserted and supported. Each connector has a circular arc part and claw parts. The circular arc part is made along a profile of a front end part of each lead wire. The claw parts are formed at both the end parts of the circular arc part. Each claw part pushes an inner wall surface of the corresponding inserting and supporting hole.

In a temperature sensor having a temperature sensitive element, a sheath pin connected to the temperature sensitive element, and a cover case. The cover case, filled with a filler, accommodates the temperature sensitive element and the sheath pin. A hardening temperature of the filler is not less than an actual usage environment of the temperature sensor. Another temperature sensor has a temperature sensitive element exposed at a high temperature of not less than 750&#xb0; C., a thermistor element, a sheath pin, an anti-vibration filler, and a metal cover case fixed to an end part of the sheath pin. The metal cover case accommodates the sheath pin and the thermistor element. The filler is made of a porous insulation material having a pore ratio within a range of 30 to 70% and filled around the thermistor element in the metal cover case.

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Kariya, Japan

Yuusuke Toudou