Ngk Spark Plug Company, Limited

Shun Sakuma

Masaki Mizutani

Masaki Onkawa

Toru Iwano

Tatsuhiko Muraoka

Shigehiro Ohtsuka

Ai Igarashi

Kouji Toida

Makoto Shimoide

Yuichi Yamada

Shigeki Mori

Shohei Yoshiyasu

Hirotaka Tsukamatsu

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 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 has a protection layer smaller in heat capacity than a conventional protection layer formed by a dipping process. A gas sensor includes the gas sensor element. The gas sensor element is manufactured by a method of manufacturing. The gas sensor element includes at least one space formed between a protection layer and an element body. The space is positioned over at least one of four vertexes of a forward end of the element body at a location at which the thickness of the protection layer is likely to become small. Therefore, it is possible to restrain breakage of the vertexes of the forward end of the element body which could otherwise result from thermal shock stemming from adhesion of water. The protection layer of the gas sensor element can be reduced in thickness and thus in heat capacity as compared with a conventional protection layer.

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

A gas sensor element in an air/fuel ratio sensor includes an element body and a protection layer having two layers (a first layer and a second layer). The gas sensor element has at least one separation portion in the form of a space between the first layer and the second layer. The gas sensor element can temporarily accumulate, in the at least one separation portion, water which adheres to the surface of the protection layer and penetrates into the protection layer. Thus, as compared with a protection layer which is identical in thickness to the protection layer, but does not have separation portions, water adhering to the protection layer is less likely to reach the element body. Therefore, there can be restrained breakage of an end of the element body which could otherwise result from thermal shock stemming from adhesion of water.

A gas sensor including a plate-shaped detecting element is disclosed, wherein the detecting element has a pair of principle surfaces and a pair of side surfaces adjacent to the pair of principle surfaces, in a radical direction thereof, wherein a first chamfered portion is provided between at least one first principal surface of the pair of principal surfaces and the rear end surface of the detecting element, and wherein the angle between a first axis ridgeline portion formed by the first principal surface and a first side surface that is one of the pair of side surfaces and extending in the direction of the axis, and a first width ridgeline formed by the first principal surface and the first chamfered portion and extending in a width direction is larger than 90&#xb0;.

Gas sensor

A gas sensor element comprises an elongated plate-like element including, at a forward end portion, a detecting section comprising a solid electrolyte body having an outer surface and a back surface, a detection electrode on the outer surface and a reference electrode on the back surface, and a porous layer covering the detection electrode. The coating layer includes a first protection layer entirely covering the detecting section, and a second protection layer circumferentially covering the first protection layer and extending at least from a forward end of the first protection layer to a position located rearward of the porous layer. The thickness of the first protection layer on the porous layer is larger than that of the first protection layer rearward of the porous layer. The thickness of the second protection layer rearward of the porous layer is larger than that of the second protection layer above the porous layer.

Gas sensor with porous protection layers

A gas sensor element having a chamfered portion. The chamfered portion has a leading end chamfered portion formed in a leading end portion of the gas sensor element, a rear end chamfered portion formed in a rear end portion of the gas sensor element, and an intermediate chamfered portion linking the leading end chamfered portion and rear end chamfered portion. The chamfer angle of the rear end chamfered portion is formed so as to be larger than the chamfer angle of the leading end chamfered portion.

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Kakamigahara, Japan

Shun Sakuma