公开(公告)号：US20220317083A1

公开(公告)日：2022-10-06

申请号：US17699896

申请日：2022-03-21

Applicant: NGK Insulators, Ltd.

Inventor： Yusuke WATANABE ,  Shotaro NIIZUMA ,  Hayami AOTA ,  Toshihiro HIRAKAWA

IPC: G01N27/407 ,  G01N27/406

Abstract: Provided is a gas sensor intended to achieve improved measurement accuracy. A gas sensor according to one aspect of the present invention includes: a gas sensor element including a gas introduction opening and a gas exhaust unit; and a protective member including a plurality of porous layers and configured to cover the gas sensor element. The plurality of porous layers include a first porous layer arranged on the innermost side and a second porous layer arranged on an outer side of the first porous layer. The first porous layer has a higher porosity than the second porous layer. The gas introduction opening and the gas exhaust unit are covered by the first porous layer. The protective member includes, between the gas introduction opening and the gas exhaust unit, a restricting portion configured to restrict the flow of gas.

公开(公告)号：US20220316985A1

公开(公告)日：2022-10-06

申请号：US17699836

申请日：2022-03-21

Applicant: NGK Insulators, Ltd.

Inventor： Yusuke WATANABE ,  Shotaro NIIZUMA ,  Hayami AOTA ,  Toshihiro HIRAKAWA ,  Kirari TAKAHASHI

IPC: G01M15/10 ,  F01N13/00

Abstract: The probability of a heater portion of a sensor element being exposed to water is lowered. The sensor element includes a built-in heater that extends in a longitudinal direction and a surrounding housing extending in the longitudinal direction. The heater includes a heat generation portion and a lead portion. The heat generation portion has a front end and a rear end, and is positioned on the same side as a front end portion side of the sensor element. The housing includes an enlarged diameter portion having a diameter of an inner wall that increases in a direction toward the front end of the sensor. The enlarged diameter portion includes a front end portion and a rear end portion. The rear end of the heat generation portion is located closer to the front end of the sensor than the rear end portion of the enlarged diameter portion is.

公开(公告)号：US20220308011A1

公开(公告)日：2022-09-29

申请号：US17702018

申请日：2022-03-23

Applicant: NGK INSULATORS, LTD.

Inventor： Yusuke WATANABE ,  Takayuki SEKIYA ,  Shotaro NIIZUMA ,  Hayami AOTA ,  Toshihiro HIRAKAWA

IPC: G01N27/41 ,  G01N33/00

Abstract: A sensor element includes a base part including a plurality of oxygen-ion-conductive solid electrolyte layers stacked; a measurement-object gas flow part for introduction and flow of a measurement-object gas through a gas inlet; an inner oxygen pump electrode disposed on an inner surface of the measurement-object gas flow part; and a measurement electrode disposed on the inner surface of the measurement-object gas flow part. The inner oxygen pump electrode includes: a region (A) including an electrode end close to the gas inlet, and a region (B) including an electrode end far from the gas inlet. A content rate of an activity reducing metal in a metal material in the region (A) is higher than that in the region (B). A ratio of the length of the region (A) of the inner oxygen pump electrode to the length of the inner oxygen pump electrode is 15% to 90%.

公开(公告)号：US20220113278A1

公开(公告)日：2022-04-14

申请号：US17497016

申请日：2021-10-08

Applicant: NGK INSULATORS, LTD.

Inventor： Yusuke WATANABE ,  Shotaro NIIZUMA ,  Hayami AOTA ,  Toshihiro HIRAKAWA

IPC: G01N27/407 ,  G01N33/00 ,  G01N27/409 ,  G01N27/41 ,  G01N27/30

Abstract: A gas sensor includes a pump electrode disposed in a measured gas flow path, an oxygen detection electrode disposed in the measured gas flow path and containing platinum and zirconia, and a reference electrode disposed in a reference gas chamber where a reference gas exists, and containing platinum and zirconia. A first position of a front end of the pump electrode is located closer to a rear end side than a second position of a front end of the oxygen detection electrode is. When the content of zirconia in the oxygen detection electrode is X [%], and a ratio of a distance between the first and second positions to a longitudinal dimension of the pump electrode is Y [%], Y≥141.96e−0.031X is satisfied. The content of zirconia is not lower than that of platinum in the reference electrode.

公开(公告)号：US20210389271A1

公开(公告)日：2021-12-16

申请号：US17460780

申请日：2021-08-30

Applicant: NGK INSULATORS, LTD.

Inventor： Ryo ONISHI ,  Yusuke WATANABE ,  Takashi HINO ,  Yasuhide KOJIMA

IPC: G01N27/407

Abstract: A sensor element includes a porous leading-end protective layer disposed around an outer periphery of an element base in a predetermined range from an end portion on a side where a sensing part is disposed, wherein the protective layer includes: a first layer disposed on two main surfaces of the element base; a second layer disposed to cover the end portion and four side surfaces of the element base including the two main surfaces on which the first layer is disposed; and a third layer disposed to cover the second layer, and having a lower porosity than the second layer, the first layer has a porosity of 40% or more, and L1≥L2 and L1≥L3 where L1, L2, and L3 are extension lengths of the first layer, the second layer, and the third layer, respectively, from an end surface of the element base in a longitudinal direction of the element base.

公开(公告)号：US20210389270A1

公开(公告)日：2021-12-16

申请号：US17460770

申请日：2021-08-30

Applicant: NGK INSULATORS, LTD.

Inventor： Ryo ONISHI ,  Yusuke WATANABE ,  Yasuhide KOJIMA ,  Takashi HINO

IPC: G01N27/407

Abstract: A sensor element includes a porous leading-end protective layer disposed around an outer periphery of an element base in a predetermined range from an end portion on a side where a sensing part is disposed, the protective layer includes: a first layer disposed on two main surfaces of the element base; a second layer disposed to cover the end portion and four side surfaces of the element base including the two main surfaces on which the first layer is disposed; and a layer disposed to cover the second layer, the second layer has a porosity of 30% to 70% and a thickness of 6 to 30 times a thickness of the first layer, and the third layer has a porosity of 10% to 40% and a thickness of 2 to 15 times the thickness of the first layer.

公开(公告)号：US20210302364A1

公开(公告)日：2021-09-30

申请号：US17205633

申请日：2021-03-18

Applicant: NGK INSULATORS, LTD.

Inventor： Yusuke WATANABE ,  Shotaro NIIZUMA

IPC: G01N27/41 ,  G01N33/00

Abstract: A sensor element includes a first pump cell including a first pump electrode and a first reference electrode, a first pump circuit including the first pump cell and a first reference electrode lead, a second pump cell including a second pump electrode and a second reference electrode and a second pump circuit including the second pump cell and a second pump electrode. A resistance value R2 of the second pump circuit is higher than a resistance value R1 of the first pump circuit, and a porosity P2 of the second reference electrode lead is higher than a porosity P1 of the first reference electrode lead.

公开(公告)号：US20210302362A1

公开(公告)日：2021-09-30

申请号：US17189295

申请日：2021-03-02

Applicant: NGK INSULATORS, LTD.

Inventor： Yusuke WATANABE ,  Kengo TERASAWA ,  Shiho IWAI

IPC: G01N27/41 ,  G01N27/407

Abstract: In a sensor element for a limiting-current type gas sensor measuring concentration of NOx in a measurement gas, an inner pump electrode located to face a first internal space communicating with a gas inlet through which the measurement gas is introduced from an external space under predetermined diffusion resistance is made of a cermet of a Pt—Au alloy and zirconia, and the inner pump electrode is located, from among surfaces defining the first internal space, at least on a surface farthest from a heater part in a thickness direction of the element, and is not located on a surface closest to the heater part in the thickness direction.

公开(公告)号：US20210302358A1

公开(公告)日：2021-09-30

申请号：US17205209

申请日：2021-03-18

Applicant: NGK INSULATORS, LTD.

Inventor： Takayuki SEKIYA ,  Yusuke WATANABE

IPC: G01N27/407 ,  G01N27/409 ,  G01N27/419 ,  G01N27/41

Abstract: A sensor element includes an element body having a measurement-object gas flow section provided therein, a first measurement pump cell that includes a first measurement electrode and that pumps out oxygen produced in a first measurement chamber from the specific gas, the first measurement electrode in the measurement-object gas flow section; and a second measurement pump cell that includes a second measurement electrode and that pumps out oxygen produced in a second measurement chamber from a specific gas, the second measurement electrode in the measurement-object gas flow section. The element body is configured such that a second diffusion resistance R2, which is a diffusion resistance of a route of a measurement-object gas from an outside to the second measurement electrode, is higher than a first diffusion resistance R1, which is a diffusion resistance of a route of the measurement-object gas from the outside to the first measurement electrode.

公开(公告)号：US20210096117A1

公开(公告)日：2021-04-01

申请号：US17030506

申请日：2020-09-24

Applicant: NGK INSULATORS, LTD.

Inventor： Yusuke WATANABE ,  Shotaro NIIZUMA ,  Hayami AOTA ,  Toshihiro HIRAKAWA

IPC: G01N33/00

Abstract: A gas sensor includes a sensor element; a plurality of contact members holding a rear end portion of the sensor element and being electrically connected to the sensor element; a plurality of lead wires that are fixed at a position rearward of the sensor element and to which the contact members are electrically connected; and metal elastic members fixing the contact members and the lead wires with the contact members and lead wires being spaced apart from each other, and electrically connecting the contact members and the lead wires.