公开(公告)号：US20210270768A1

公开(公告)日：2021-09-02

申请号：US17170940

申请日：2021-02-09

Applicant: NGK INSULATORS, LTD.

Inventor： Taku OKAMOTO ,  Yuichiro KONDO ,  Osamu NAKASONE

IPC: G01N27/41 ,  G01N27/406

Abstract: A gas sensor includes a sensor element including an element body, a first electrode, a second electrode, and a heater; a voltage acquisition section that acquires a voltage between the first electrode and the second electrode; a heater power supply; an external common lead that serves as both at least part of an electric circuit used to acquire the voltage by providing electrical continuity between the first electrode and the voltage acquisition section and at least part of an electric circuit used to supply an electric power from the heater power supply to the heater and that is disposed outside the sensor element; and a correction section that derives a value of a voltage drop in the external common lead in accordance with a heater current and that corrects the voltage acquired by the voltage acquisition section in accordance with the derived value of the voltage drop.

公开(公告)号：US20200309727A1

公开(公告)日：2020-10-01

申请号：US16819813

申请日：2020-03-16

Applicant: NGK INSULATORS, LTD.

Inventor： Taku OKAMOTO ,  Osamu NAKASONE ,  Nobukazu IKOMA ,  Noriko HIRATA

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

Abstract: A gas sensor includes an element body including oxygen-ion-conductive solid electrolyte layers and having a measurement-object gas flow section inside the element body; a main pump cell configured to adjust the oxygen concentration in a first internal cavity; an auxiliary pump cell configured to adjust the oxygen concentration in a second internal cavity; a measurement electrode disposed on an inner peripheral surface of a third internal cavity; and a reference electrode. An inner pump electrode of the main pump cell does not contain a noble metal having a catalytic activity inhibition ability. An auxiliary pump electrode of the auxiliary pump cell contains the noble metal having the catalytic activity inhibition ability.

公开(公告)号：US20200080460A1

公开(公告)日：2020-03-12

申请号：US16555003

申请日：2019-08-29

Applicant: NGK INSULATORS, LTD.

Inventor： Taku OKAMOTO ,  Osamu NAKASONE ,  Kosuke MONNA

IPC: F01N11/00 ,  F02D41/14

Abstract: A catalyst deterioration diagnosis method is a method for a system. The system includes a gas sensor having ammonia interference property that measures an air-fuel ratio and nitrogen oxide concentration of an exhaust gas that has passed through a catalyst. Monitoring of temporary increase of nitrogen oxide concentration to be detected by the gas sensor is started, and thereby a temporarily increased amount of the nitrogen oxide concentration is acquired. The monitoring is started when a fuel injection device restarts fuel injection after a fuel cut in a case where an air-fuel ratio most recently obtained by the gas sensor is larger than a predetermined threshold air-fuel ratio. The predetermined threshold air-fuel ratio is larger than a stoichiometric air-fuel ratio. Whether or not the temporarily increased amount is larger than a threshold amount is determined.

公开(公告)号：US20190383766A1

公开(公告)日：2019-12-19

申请号：US16438524

申请日：2019-06-12

Applicant: NGK INSULATORS, LTD.

Inventor： Kunihiko NAKAGAKI ,  Taku OKAMOTO ,  Osamu NAKASONE ,  Nobukazu IKOMA

IPC: G01N27/406 ,  F01N11/00 ,  G01N27/409 ,  G01N27/41 ,  G01N27/416 ,  F01N3/20

Abstract: A first gas sensor includes a main pump cell that pumps oxygen inside a main oxygen concentration adjustment chamber, by applying a main pump voltage between a main interior side electrode and an exterior side electrode, and causing a main pump current to flow, a preliminary pump cell that pumps the oxygen inside a preliminary adjustment chamber by applying a preliminary pump voltage between an interior side preliminary electrode and the exterior side electrode, and causing a preliminary pump current to flow, and a constant control unit that controls the preliminary pump voltage of the preliminary pump cell in a manner so that the main pump current of the main pump cell becomes constant.

公开(公告)号：US20190277797A1

公开(公告)日：2019-09-12

申请号：US16297943

申请日：2019-03-11

Applicant: NGK INSULATORS, LTD.

Inventor： Taku OKAMOTO

IPC: G01N27/407 ,  G01N27/30 ,  G01N27/409

Abstract: A mixed-potential type gas sensor includes: a first sensing electrode containing a Pt—Au alloy and a second sensing electrode containing Pt, both sensing electrodes being provided on the surface of a sensor element made of an oxygen-ion conductive solid electrolyte; a reference electrode provided inside the sensor element to be made contact with air; a first protective layer group covering the first sensing electrode; a second protective layer group covering the second sensing electrode; and concentration identification element configured to identify the concentration of a sensing target gas component based on potential differences between both of the first sensing electrode and the second sensing electrode and the reference electrode. The response times of the first and second sensing electrodes are both equal to or shorter than 10 seconds, and the response time difference therebetween is 2 seconds or shorter.

公开(公告)号：US20190277795A1

公开(公告)日：2019-09-12

申请号：US16297958

申请日：2019-03-11

Applicant: NGK INSULATORS, LTD.

Inventor： Taku OKAMOTO

IPC: G01N27/407

Abstract: A mixed-potential gas sensor includes: a first sensing electrode containing a Pt—Au alloy and a second sensing electrode containing Pt, the first and second sensing electrodes being provided on a surface of a sensor element made of an oxygen-ion conductive solid electrolyte on one leading end part side; a reference electrode provided inside the sensor element to be made contact with air; a protective cover that surrounds the one leading end part of the sensor element and into which measurement gas flows; and concentration identification element configured to identify a concentration of a sensing target gas component based on potential differences between both of the first sensing electrode and the second sensing electrode and the reference electrode. The first and second sensing electrodes are disposed so that the measurement gas flowing into the protective cover reaches the first sensing electrode earlier than the second sensing electrode.

公开(公告)号：US20190025244A1

公开(公告)日：2019-01-24

申请号：US16035750

申请日：2018-07-16

Applicant: NGK INSULATORS, LTD.

Inventor： Taku OKAMOTO ,  Yuki NAKAYAMA ,  Soichiro YOSHIDA

IPC: G01N27/407 ,  G01N27/417 ,  G01N27/30 ,  G01N27/406

CPC classification number: G01N27/4071 ,  G01N27/301 ,  G01N27/4067 ,  G01N27/4076 ,  G01N27/4077 ,  G01N27/4175

Abstract: A gas sensor includes a sensor element made of an oxygen-ion conductive solid electrolyte and is configured to determine a concentration of a measurement target gas component based on a sensitivity characteristic as a predetermined functional relation held between a sensor output and the concentration of the gas component. The sensor output is a potential difference generated between a sensing electrode of the sensor element heated to a predetermined sensor drive temperature and a reference electrode. At the reference electrode, Au is concentrated at a predetermined maldistribution degree on the surface of a noble metal particle. In the present invention, the sensitivity characteristic is calibrated so as to suit the maldistribution degree at the reference electrode, based on the value of a predetermined alternative maldistribution degree index acquired in a non-destructive manner by performing predetermined measurement while the sensor element is heated to the predetermined temperature.

公开(公告)号：US20170276052A1

公开(公告)日：2017-09-28

申请号：US15454083

申请日：2017-03-09

Applicant: NGK INSULATORS, LTD.

Inventor： Kosuke MONNA ,  Taku OKAMOTO ,  Takayuki SAKURAI ,  Noriko HIRATA

IPC: F01N11/00 ,  G01N33/00

CPC classification number: F01N11/007 ,  B01D53/944 ,  B01D53/9495 ,  F01N3/0814 ,  F01N3/0835 ,  F01N3/0857 ,  F01N3/103 ,  F01N11/00 ,  F01N11/002 ,  F01N2550/02 ,  F01N2550/03 ,  F01N2560/023 ,  F01N2560/06 ,  F01N2900/1402 ,  F01N2900/1404 ,  G01N33/0036 ,  Y02T10/47

Abstract: Provided is a method for accurately diagnosing a degree of degradation of an oxidation catalyst. A target gas detecting element configured to output an electromotive force corresponding to a concentration of a target gas is provided downstream of a catalyst in an exhaust path of an internal combustion engine. A maximum change amount of an electromotive force after the introduction of a gas atmosphere for diagnosis into the catalyst is set as a diagnosis index value. The gas atmosphere has been intentionally created in the engine and includes a target gas having a concentration higher than the concentration of a target gas in a steady operation state of the engine. The index value is then compared with a threshold corresponding to the temperature of the catalyst to diagnosis whether degradation exceeding an acceptable degree has occurred in the catalyst.

公开(公告)号：US20170138894A1

公开(公告)日：2017-05-18

申请号：US15290063

申请日：2016-10-11

Applicant: NGK INSULATORS, LTD.

Inventor： Taku OKAMOTO ,  Noriko HIRATA ,  Yuki NAKAYAMA ,  Osamu NAKASONE

IPC: G01N27/407

Abstract: A mixed-potential gas sensor for measuring a concentration of a predetermined gas component of a measurement gas includes sensing electrodes mainly made of an oxygen-ion conductive solid electrolyte and located on a surface of a sensor element, and at least one reference electrode including a cermet including Pt and an oxygen-ion conductive solid electrolyte. The sensing electrodes each include a cermet including a noble metal and an oxygen-ion conductive solid electrolyte. The noble metal includes Pt and Au. A Au abundance ratio, which is an area ratio of a portion covered with the Au to a portion at which the Pt is exposed in a surface of noble metal particles forming each of the sensing electrodes, differs among the sensing electrodes. The gas sensor determines a concentration of the predetermined gas component based on a potential difference between each of the sensing electrodes and the at least one reference electrode.

公开(公告)号：US20170138893A1

公开(公告)日：2017-05-18

申请号：US15347086

申请日：2016-11-09

Applicant: NGK INSULATORS, LTD.

Inventor： Yuki NAKAYAMA ,  Noriko HIRATA ,  Taku OKAMOTO ,  Osamu NAKASONE

IPC: G01N27/407 ,  G01N27/30

Abstract: A gas sensor with excellent detection sensitivity is provided. A sensing electrode, which is provided in a mixed-potential gas sensor for measuring a concentration of a predetermined gas component of a measurement gas to sense the predetermined gas component, is formed of a cermet of a noble metal and an oxygen-ion conductive solid electrolyte. The noble metal includes Pt and Au. A range of at least 1.5 nm from a surface of a noble metal particle included in the sensing electrode is a Au enriched region having a Au concentration of 10% or more.