Ngk Spark Plug Company, Limited

Ai Igarashi

Satoshi Okazaki

Kouji Toida

Masaki Mizutani

Shun Sakuma

Akinori Kojima

Hitoshi Furuta

Hiroyuki Hayashi

Nobuo Furuta

Kaoru Hisada

Tomohisa Terui

Akihiro Hara

Noboru Furuta

A method for manufacturing a sensor element that includes: a pair of electrodes; a ceramic layer having a hollow space that is to be an air introduction hole; and a first layer and a second layer stacked at both surfaces of the ceramic layer, One of the electrodes is in communication with the hollow space, The method includes: preparing an unsintered ceramic sheet, and a burn-out material sheet having a thickness different from that of the unsintered ceramic sheet, the burn-out material sheet having, in a plane orthogonal to the direction of an axial line O, a cross-sectional area substantially identical to a cross-sectional area of the pre-sintering hollow space; placing the burn-out material sheet in the pre-sintering hollow space; pressing the sheets so as to have an identical thickness; and burning out the burn-out material sheet.

Method for manufacturing sensor element

A plate-shaped sensor element () including at least a first layer (), a second layer (), and a third layer () being stacked in a stacking direction. The first layer and the third layer are mainly formed of ceramic. The second layer is disposed between the first layer and the third layer in the stacking direction. The second layer has an air introduction hole () opened at an end surface. In a cross-section perpendicular to a direction of an axis O, a length Lof a shortest line segment Pconnecting an upper end surface () of the sensor element and the centroid Gof the sensor element and a length Lof a shortest line segment Pconnecting the upper end surface of the sensor element and the centroid Gof the air introduction hole, satisfy a relationship of |L&#x2212;L|/L&#x2264;0.05.

Sensor element and gas sensor including the sensor

A method for producing a gas sensor element (), the gas sensor element including a diffusive porous layer () disposed in a measurement chamber () and exposed to the outside and a ceramic insulating layer () forming sidewalls of the measurement chamber. The method includes transferring green diffusive porous layer pieces () cut in advance so as to have prescribed dimensions onto a first ceramic green sheet (); applying an insulating paste which later becomes the ceramic insulating layer to the first ceramic green sheet; laminating the first ceramic green sheet onto a second ceramic green sheet () to form a ceramic laminate (); cutting the ceramic laminate along prescribed cutting lines C to obtain a plurality of gas sensor element pieces; and firing the gas sensor element pieces.

Method for producing gas sensor element

A gas sensor element comprises a solid electrolyte layer; a detection electrode provided on one surface of the solid electrolyte layer; a reference electrode provided on another surface of the solid electrolyte layer; a first layer provided on a side where the other surface of the solid electrolyte layer is present, and having a reference gas flow path; and a heater layer provided on a side opposite to a side where the solid electrolyte layer is provided. In the gas sensor element, an introduction flow path is formed as a flow path for guiding the reference gas from outer surfaces of the gas sensor element to the reference gas flow path. The introduction flow path has an opening provided at an outer surface that is perpendicular to a stacking direction of the gas sensor element and is provided on a side opposite to the heater layer.

Gas sensor element and gas sensor

A gas sensor element including a composite ceramic layer including a plate-shaped insulating portion containing an insulating ceramic and having a through hole formed therein and a plate-shaped electrolyte portion containing a solid electrolyte ceramic and disposed in the through hole; and a first conductor layer extending continuously from a first insulating surface on one side of the insulating portion to a first electrolyte surface of the electrolyte portion facing the same direction as the one side of the insulating portion. The first insulating surface is flush with the first electrolyte surface. The electrolyte portion has, on its first electrolyte surface side, an extension portion extending outward from the through hole so as to overlap the first insulating surface. Further, the thickness of the extension portion decreases toward the outer circumference of the extension portion. Also disclosed is a method of manufacturing the gas sensor element.

Gas sensor element, gas sensor, and method of manufacturing gas sensor element

A gas sensor element that includes a composite ceramic layer including a plate-shaped insulating portion which contains an insulating ceramic and has a through-hole, and an electrolyte portion which contains a solid electrolyte ceramic, and a portion disposed in the through-hole where the electrolyte portion is thicker than the insulating portion. A first conductor layer is formed over a first insulating surface of the insulating portion and a first electrolyte surface of the electrolyte portion. The electrolyte portion has an extending portion which is overlaid on the first insulating surface and extends toward the outside of the through-hole. The thickness of the extending portion is decreased toward an outer periphery of the extending portion, and the outer periphery of the extending portion is continuously connected to the first insulating surface. A first extending surface of the extending portion continuously connects the first insulating surface and the first electrolyte surface.

Gas sensor element, gas sensor, and method for manufacturing gas sensor element

A gas sensor element () includes a first composite ceramic layer () having a plate-shaped first surrounding portion () formed of an insulating ceramic and including a through hole inner-perimetric-surface () which defines a through hole (), and a plate-shaped first electrolyte portion () formed of a solid electrolyte ceramic, disposed in the through hole (), and including an electrolyte outer-perimetric-surface () in contact with the through hole inner-perimetric-surface (). The electrolyte outer-perimetric-surface () of the first electrolyte portion () is sloped toward an exterior of the first electrolyte portion () as it approaches one side DT. The through hole inner-perimetric-surface () and the electrolyte outer-perimetric-surfaceare in close contact with each other along their entire perimeters.

A heater control method and apparatus for a gas sensor which can quickly activate a detection element while reducing load due to heating even when a higher power supply voltage is applied. A heater element is connected to a power supply whose voltage is higher than 16 V, and power is supplied under PWM control such that a temperature rise of the heater element follows a temperature rise curve obtained when a voltage of 12 V is applied to the heater element. Even though a higher voltage is applied, the temperature rise per unit time during the ON time of the PWM control is decreased. This is because the ON time per cycle is shortened by increasing the PWM frequency to 30 Hz or higher. Thus, the temperature rise per cycle is kept low, whereby the temperature rise per 0.1 second is rendered less than 25&#xb0; C.

Heater control method and heater control apparatus for gas sensor

A gas sensor including a plate-shaped laminate disposed in a housing and fixed thereto via an element passage member and formed by laminating a gas sensor element and a heating element. The gas sensor element includes a plate-shaped solid electrolyte member, and a pair of detection electrodes formed on front and back surfaces thereof and constituting, in cooperation with the solid electrolyte member, a detection section for detecting the concentration of a specific gas. Insulating substrates mainly composed of alumina are provided on opposite sides of the laminate in the laminating direction. Coating layers mainly composed of a first material higher in toughness than alumina are formed on at least portions of outer surfaces of the insulating substrates in the laminating direction, the portions facing the element passage member. The coating layers are not formed on surfaces of the laminate parallel to the laminating direction.

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Konan, Japan

Ai Igarashi