Denso Corporation

Nippondenso Co., Ltd.

Tomio Sugiyama

Hiromi Sano

Shinichiro Imamura

Makoto Nakae

Masahiro Shibata

Syuichi Nakano

Masatoshi Suzuki

Naoto Miwa

Toshitaka Saito

Akio Tanaka

Satoru Nomura

Isao Watanabe

Satoshi Hada

Keigo Mizutani

Namitsugu Fujii

Takehito Kimata

Kazuya Nakagawa

Susumu Naito

Tomoji Fukaya

Hiroshi Furuhashi

Kazuo Matsubara

Hiromi Inada

Kouji Hori

Hirohiko Tatumoto

Yasushi Miyamura

Raina Shibata, Legal Representative

Masahiro Sibata, Deceased

Masahiro Shibata, Deceased

Midori Shibata, Legal Representative

Shouzo Tanida

Natsumi Shibata, Legal Representative

In a method of detecting defects generated in a honeycomb structural body, both end sections of the honeycomb structural body is sealed along a flowing direction of exhaust gas. Air is supplied in the flowing direction of the exhaust gas from one end section to the other end section of the honeycomb structural body. Microphones are arranged at outer periphery of the honeycomb structural body and detect sounds of air leaking from a skin layer of the honeycomb structural body. A judgment step judges whether or not defects such as holes having not less than a predetermined diameter and cracks are generated on the basis of a magnitude of the detected sounds of the leaking air.

Method of detecting defects in honeycomb structural body

A multilayered air-fuel ratio sensor consists of a plurality of substrate layers. At least one heterogeneous boundary layer is interposed between the plurality of substrate layers. The heterogeneous boundary layer has a thickness in a range of 10 to 100 &#x3bc;m. The heterogeneous boundary layer absorbs thermal shocks or any other stresses acting on the substrate layers and stops the growth of cracks.

Multilayered air-fuel ratio sensor

A gas sensor element which may be employed in measuring the concentration of gas such O, NOx, or CO. The gas sensor element consists of an electrochemical cell made up of a solid electrolyte body formed by a partially stabilized zirconia and a pair of electrodes disposed on the solid electrolyte body. The electrochemical cell is subjected to an aging treatment in which the dc current is applied to the electrodes at a given voltage to enhance the activation of the electrochemical cell.

Gas sensor element

A gas sensing element includes a solid electrolytic substrate having oxygen ion conductivity, a measured gas side electrode provided on a surface of the solid electrolytic substrate so as to be exposed to a measured gas, and a reference gas side electrode provided on another surface of the solid electrolytic substrate so as to be exposed to a reference gas. The measured gas side electrode is covered by a porous electrode protecting layer. A limit current density of the electrode protecting layer is in a range from 0.04 mA/mmto 0.15 mA/mmon a unit area of the reference gas side electrode.

Gas sensing element

A nonfragile ad quickly activatable structure of a gas sensor element which may be built in a gas sensor employed in an air-fuel ratio control system for automotive vehicles for measuring the concentration of gas such O , NOx, or CO. The gas sensor element is made of a lamination of a measurement gas electrode, a reference gas electrode, and a heater. The heater works to elevate the temperature of the gas sensor element up to a given value required to bring the gas sensor element into an activated condition. The heater includes a heater substrate, a heating element, and power supply leads. A minimum distance X between an edge of the heater substrate and an edge of the heating element meets a relation of 0.1 mm&lE;X&lE;0.6 mm, thereby minimizing a thermal expansion difference between the heater element and the heater substrate to avoid cracks in a portion of the heater substrate near the heater element. It also becomes possible to elevate the temperature of the heating element up to a higher value, thereby allowing the gas sensor element to be activated quickly immediately after the power is supplied to the heating element.

Nonfragile and quickly activatable structure of gas sensor element

A multilayered air-fuel ratio sensing element comprises a solid electrolytic substrate having oxygen ion conductivity. A measuring gas sensing electrode is provided on one surface of the solid electrolytic substrate so as to be exposed to a measuring gas. A reference gas sensing electrode is provided on another surface of the solid electrolytic substrate so that the reference gas sensing electrode is exposed to a reference gas introduced into a reference gas chamber. The measuring gas sensing electrode is covered by a porous diffusive resistor layer. And, a hollow space is provided between the measuring gas sensing electrode and the porous diffusive resistor layer.

Multilayered air-fuel ratio sensing element

A gas sensor includes a body having a measurement-gas chamber and a reference-gas chamber. The measurement-gas chamber is supplied with a measurement gas. The reference-gas chamber is supplied with a reference gas. A detecting cell provided in the body includes (1) a solid electrolyte member, (2) a measuring electrode provided on the solid electrolyte member and facing the measurement-gas chamber, and (3) a reference electrode provided on the solid electrolyte member and facing the reference-gas chamber. A heater portion operates for heating the detecting cell. The heater portion includes (1) a first substrate, (2) a heating member provided on the first substrate, (3) a high-voltage-side lead portion provided on the first substrate and electrically connected to the heating member, (4) a low-voltage-side lead portion provided on the first substrate and electrically connected to the heating member, and (5) a second substrate covering the heating member. The first substrate has a first surface and a second surface opposite to each other. The first surface of the first substrate faces the body. The heating member extends on the first surface of the first substrate. The high-voltage-side lead portion extends on the second surface of the first substrate.

Gas sensor

A composite gas sensor comprises a pump cell, a NOx sensor cell and an oxygen sensor cell. The NOx sensor cell is connected to a first ammeter and a constant power source to measure the NOx concentration of a sample gas. The pump cell is connected to a second ammeter and a variable power source to measure an air-fuel ratio of the sample gas. The oxygen sensor cell is connected to a voltmeter. A controller adjusts the variable power source to produce a constant value from the voltmeter.

Composite gas sensor

A multilayered air-fuel ratio sensing element has a zirconic solid electrolytic body and a heat-generating portion including an alumina substrate located adjacent to the zirconic solid electrolytic body. The zirconic solid electrolytic body is made of a partially stabilized zirconia containing 5&tilde;7 mol % yttria and having a mixed phase structure including a cubic phase, a monoclinic phase and a tetragonal phase. The zirconic solid electrolytic body has a relative density of 94&tilde;100% with a mean sintered grain size R,of 0.5&tilde;3.0 &mgr;m. The alumina substrate has a relative density of 95&tilde;100% with a mean sintered grain size R,of 0.5&tilde;4.0 &mgr;m. And, the partially stabilized zirconia has an M/C ratio in a range from 0.05 to 0.25.

A gas sensing element having a sample gas chamber into which a sample gas is introduced, and a reference gas chamber into which a reference gas is introduced. A sensor cell detects a specific gas concentration in the sample gas chamber. An oxygen pump cell pump cell pumps oxygen gas from or to the sample gas chamber. An introducing passage includes at least one pinhole provided on a surface of the oxygen pump cell for introducing the measuring gas into the sample gas chamber. The surface of the oxygen pump cell faces an outside of the gas sensing element. And, a porous diffusion resistive layer is provided on the surface of the oxygen pump cell so as to cover a portion corresponding to the introducing passage, thus serving to reduce or eliminate the effects of temperature dependency upon gas sensor output for properly sized and machine pinholes.

Gas sensing element and a method for measuring a specific gas concentration

First and second solid electrolyte bodies are opposed to one another to form a reference gas chamber therebetween. A measurement cell for detecting an air fuel ratio in measurement gas is provided on the first solid electrolyte body with a measurement electrode exposed to the measurement gas and a reference electrode exposed to the reference gas chamber. An oxygen pump cell is provided on the second solid electrolyte body with a first pump electrode exposed to the measurement gas and a second pump electrode exposed to the reference gas chamber. When a voltage is applied to the first and second oxygen pump cell, the oxygen gas is introduced from the measurement gas into the reference gas chamber.

Air fuel ratio sensor with oxygen pump cell

A main body of a NOx sensor has a sensor cell and defines a reference gas chamber and a sample gas chamber therein. The sample gas chamber has a wall formed by a solid electrolytic substrate having an oxygen ion conductivity. The sensor cell is disposed between the reference gas chamber and the sample gas chamber for detecting a concentration of a NOx gas. A pump cell body of the NOx sensor has a surface facing to the sample gas chamber and has a pump cell for introducing and exhausting an oxygen gas to and from the sample gas chamber. In manufacturing this NOx sensor, the main body and the pump cell body are fabricated individually as separate items. The main body and the pump cell body are sintered independently. Then, the main body and the pump cell body are assembled into to the NOx sensor.

NOx sensor and manufacturing method of the same

A gas concentration detector comprises a plate sensor element including a sensing action and a signal output section. A flange section is formed between the sensing section and the signal output section so as to protrude in the lateral direction thereof. A cylindrical housing has an inside space for receiving the sensor element. Powder is disposed in the inside space of the cylindrical housing at a predetermined position adjacent to the flange section so that the sensor element is airtightly fixed to the housing by applying a pressing force on the powder. Furthermore, a cross-sectional area of the signal output section is larger than a cross-sectional area of the sensing section.

Gas concentration detector

An air-fuel ratio sensing element comprises a pump cell having at least one pair of pump electrodes thereon, a sensor cell having at least one pair of sensor electrodes thereon, and a gas chamber having two surfaces defined by the pump cell and the sensor cell. Two to five gas holes, each having approximately the same diameter and communicating with the gas chamber, are provided for introducing sensed gas into the gas chamber. The gas holes form their projection images on the surface of the sensor cell which has a sensor electrode thereon and faces the gas chamber. The sensor electrode is shaped such that it is dividable into a plurality of similar subsections defined by virtual lines connecting the geometric centroid of the sensor electrode and the center of the projection image of each gas hole.

Air-fuel ratio sensing element

An air-fuel ratio sensor unit including a plate shaped pumping cell 11 with a pin hole 110, a sensing cell 12 including a reference gas chamber 160, a first and a second heating plates 13 and 14 which are arranged to contact with the top and bottom surfaces, respectively, of the pumping cell 11, and a spacer 15 arranged between the first heater 13 and the sensing cell 12. The spacer 15, and the first and the second heater plates 13 and 14 form a passageway for a gas to be detected.

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Nagoya, Japan

Tomio Sugiyama