Ngk Spark Plug Company, Limited

Honda Motor Co., Ltd.

Mineji Nasu

Seiji Oya

Tomohiro Wakazono

Akio Takami

Toshitaka Matsuura

Koji Shiotani

Tomonori Kondo

Keizo Furusaki

Hiroshi Kubota

Koichi Awano

Kazuo Yanada

Noriaki Kondo

Ken Minoha

Akio Mizutani

Toshifumi Sekiya

Teppei Okawa

A gas sensor controllerstops an operation of pumping in or out oxygen that is being performed by a first pump cellin a state that the oxygen concentration (oxygen partial pressure) of a gas to be measured is equal to a status judgment reference value (20%). The gas sensor controllercalculates an oxygen pressure in a second measurement chamberon the basis of a second pump current Ip. If the oxygen pressure in the second measurement chamberis equal to a deterioration judgment reference value, the gas sensor controllerjudges that the second pump cellis in a normal state. If the oxygen pressure in the second measurement chamberis different from the deterioration judgment reference value, the gas sensor controllerjudges that the second pump cellis in a deteriorated state.

Sensor deterioration judging apparatus and sensor deterioration judging method

A sensor element having a plate-like shape and extending in a longitudinal direction and having a chamfered portion at an edge between a main surface and a rear-end surface or between a main surface and a side surface of the sensor element. The sensor element includes a solid electrolyte layer, an insulating layer disposed on the solid electrolyte layer and constituting at least part of the main surface, and an electrode pad disposed away from the chamfered portion for connection to an outside circuit. Furthermore, the solid electrolyte layer and the insulating layer are exposed at the chamfered portion. Also disclosed are a gas sensor including the sensor element and a method of manufacturing the sensor element.

Sensor element, gas sensor, and method of manufacturing the sensor element

A plural-cell gas sensor including at least an oxygen pump cell () comprising a solid electrolyte ceramic layer; an internal space () formed between the cells; and a heater substrate () arranged on the side of the oxygen pump cell; the heater substrate heating the oxygen pump cell that pumps oxygen out of the internal space.

Plural-cell gas sensor with heater

A sensor element including: a first solid electrolyte layer as defined herein; and a second solid electrolyte layer as defined herein, wherein the first solid electrolyte layer includes a first inner insulating layer, a first outer insulating layer, a first inner conductive layer and a first outer conductive layer as defined herein, the second solid electrolyte layer includes a second inner insulating layer, a second outer insulating layer, a second inner conductive layer and a second outer conductive layer as defined herein, and the first outer conductive layer and the second outer conductive layer are in contact with one another.

Sensor element, method of manufacturing a sensor element, and gas sensor

In a sensor diagnosis process, a controller for controlling an NOx gas sensor performs processing of changing the oxygen partial pressure in a second measurement chamber by changing the oxygen partial pressure in a first measurement chamber (S), processing of detecting a current flowing through a second pump cell before the change of the oxygen partial pressure (S), and processing of detecting a current flowing through the second pump cell after the change of the oxygen partial pressure (S). Furthermore, the controller performs processing of judging whether or not the ratio between the current values detected by the respective current detecting unit falls within an allowable range, judging that the second pump cellis in a normal state if the ratio between the current values falls within the allowable range, and judging that the second pump cellis in a deteriorated state if the ratio between the current values is out of the allowable range (Sand S).

The invention relates to a method of producing a gas sensor element having a porous film formed by a thick-film technique on a ceramic substrate surface so as to cover selected portions of electrode films precedingly formed on the substrate surface. The electrode material is a noble metal such as platinum. Both the electrode films and the gas sensitive porous thick-film are formed by known methods. To improve the contact between the gas sensitive porous thick-film and the electrode films both mechanically and electrically and stabilize the internal resistance of the sensor element by depositing a noble metal such as platinum at the interface between the porous thick-film and each electrode film, the porous thick-film is impregnated with a solution of a noble metal compound such as chloroplatinic acid and thereafter maintained in a reducing gas atmosphere having a controlled humidity in the range from 5 to 90% (relative humidity) at a temperature in the range from 10.degree. C. to 135.degree. C.

Method of producing thick-film gas sensor element having improved

A laminar gas-sensitive thick film consisting of ceramic semiconductor and metallic catalyzer is formed across a pair of electrodes carried by a ceramic substrate, and the nature of metallic catalyzer on an outer surface layer of the thick film is different from that of metallic catalyzer in that portion of the thick film which is in the proximity of the electrodes.

Thick-film gas-sensitive element

An apparatus for evaluating an oxygen sensor includes a device for mixing a fuel and an oxygen-containing gas in an appropriate ratio to prepare a fuel mixture. A burner is connected to the mixing device for burning the fuel mixture to produce a gaseous combustion product. A tubular member extends from the burner for supplying the combustion product. A nozzle is connected to the tubular member for introducing a fuel and an oxygen-containing gas into the tubular member so that the combustion product is of a desired excess air ratio (air-fuel ratio) and a mounting device for the sensor to be evaluated is disposed on the tubular member, downstream of the nozzle.

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Kounan, Japan

Mineji Nasu