Ngk Spark Plug Company, Limited

Honda Motor Co., Ltd.

Tomohiro Wakazono

Seiji Oya

Koji Shiotani

Mineji Nasu

Tomonori Kondo

Masaki Nakagawa

Hiroshi Kubota

Kazuo Yanada

Koichi Awano

Seiji Ohya

Kenji Kato

Hitoshi Furuta

Hisashi Sasaki

Takashi Nakao

Kentaro Kamada

Takashi Konno

The gas sensor includes a gas sensor element, a casing, and an insulating inner member contained inside the casing. The gas sensor element includes a detection element and a heater. The detection element includes one or more cells each having a solid electrolyte body and a pair of electrodes. Each of the opposite side surfaces of the detection element includes a region including a smallest current cell and extending forward of the smallest current cell in the direction of an axial line. The region and the forward-facing surface of the detection element are covered with a glass coating having a glass transition point of higher than 700&#xb0; C. but not higher than 800&#xb0; C. and a porosity of 3.0% or less. The detection element is controlled to have a temperature equal to or lower than the glass transition point of the glass coating.

Gas sensor

In a gas sensor element of a gas sensor, reference oxygen chamber () assumes the shape of a rectangular parallelepiped. A reference electrode () is disposed on a surface of a third solid electrolyte body () which is exposed to the reference oxygen chamber (). A second outer electrode () is disposed opposite the reference electrode, on a surface of a second solid electrolyte body () which is exposed to the reference oxygen chamber. Further, a porous, insulative protection layer () is formed so as to cover the entire surface of the second outer electrode. A gap () is present between the reference electrode and the insulative protection layer. The thickness of the gap is greater than that of the insulative protection layer.

A gas sensor includes a gas sensor element. The gas sensor element includes a first detection chamber; a first oxygen pumping cell including a first solid electrolyte body and a pair of first electrodes; a second detection chamber; a second oxygen pumping cell including a second solid electrolyte body and a pair of second electrodes; and an oxygen-concentration sensing cell including a third solid electrolyte body and a pair of third electrodes. A sensing electrode of the third electrodes is disposed downstream beyond a first inner electrode of the first electrodes relative to a gas flow direction. A cross-sectional area of a space of the first detection chamber which faces the first inner electrode falls within a range from 0.03 mmto 0.22 mm. A center of the sensing electrode is located downstream beyond a downstream end of the first inner electrode to cause a distance between the center of the sensing electrode and the downstream end of the first inner electrode to be greater than or equal to ten times magnitude of a height of the space.

A gas sensor including a gas sensor element having a first measurement chamber (); a first pumping cell (); a second measurement chamber () into which a gas to be measured having a controlled oxygen partial pressure is introduced; and a second pumping cell () having a second inner pump electrode () and a second counterpart electrode () pump electrode configured to detect a specific gas component. The second inner pump electrode is made of a material that contains, as a principal ingredient, two kinds of Pt particles having different particle sizes and whose particle size ratio measured by a sedimentation particle-size distribution ranges from 1.75 to 14.2. A mixing ratio between large Pt particles and small Pt particles has a mass ratio of 10/90 to 50/50. A 10 kHz-1 Hz resistance value across the second pumping cell at 600&#xb0; C. is 150&#x3a9; or less.

Gas sensor and method for manufacturing the same

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 gas sensor () has a gas sensor element () including a first measurement chamber (); a first pumping cell () having a first interior pump electrode () and its counterpart electrode (); a second measurement chamber (); a second pumping cell () that has a second interior pump electrode (); and a beater (). The heater () has a lead section (); a first resistance portion () having a higher resistance than the lead portion (); and a main heating portion () having a second resistance portion () having a higher resistance than the first resistance portion () disposed at a leading end side in a longitudinal direction relative to a leading end of the first resistance portion (). The second interior pump electrode () is located within the first resistance portion () in the longitudinal direction.

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 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).

Growing community of inventors

Konan, Japan

Tomohiro Wakazono