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公开(公告)号：US10428717B2
公开(公告)日：2019-10-01
申请号：US15640683
申请日：2017-07-03
申请人： NGK INSULATORS, LTD.
发明人： Kosuke Monna , Taku Okamoto , Noriko Hirata
摘要： Provided is a method for diagnosing whether an oxidation catalyst has degraded, based on an output value from one diagnostic sensor with higher accuracy. When a ratio of nitrogen monoxide that is oxidized by a catalyst and discharged downstream of the catalyst as nitrogen dioxide, with respect to nitrogen monoxide contained in an exhaust gas supplied upstream of the catalyst in an exhaust path is defined as a NO conversion rate, a diagnostic sensor configured to output an electromotive force corresponding to the NO conversion rate as a diagnostic output is provided downstream of the catalyst in the exhaust path, and whether the catalyst has degraded beyond an acceptable limit is diagnosed by comparing the diagnostic output with a threshold value predetermined depending on a temperature of the catalyst.
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公开(公告)号：US10895189B2
公开(公告)日：2021-01-19
申请号：US16555003
申请日：2019-08-29
申请人： NGK INSULATORS, LTD.
发明人： Taku Okamoto , Osamu Nakasone , Kosuke Monna
摘要： 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.
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公开(公告)号：US10914696B2
公开(公告)日：2021-02-09
申请号：US16688101
申请日：2019-11-19
申请人： NGK INSULATORS, LTD.
发明人： Taku Okamoto , Yuki Nakayama , Kosuke Monna , Osamu Nakasone
IPC分类号： G01N27/02 , G01N27/407 , G01N27/417
摘要： Provided is a method of suitably judging necessity of a recovering process carried out on a mixed-potential gas sensor based on an extent of reversible deterioration occurring in a sensing electrode. The method includes the steps of: (a) performing impedance measurement between a sensing electrode exposed to a measurement gas and a reference electrode exposed to a reference atmosphere, which are provided in the gas sensor; and (b) judging necessity of a recovering process based on electrode reaction resistance or a diagnosis parameter correlating with the electrode reaction resistance wherein the electrode reaction resistance and the diagnosis parameter are obtained based on a result of the impedance measurement. The two steps are intermittently or periodically repeated during use of the gas sensor, and it is judged that a recovering process is necessary when the judge parameter satisfies a predetermined threshold condition in the step (b).
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公开(公告)号：US10125656B2
公开(公告)日：2018-11-13
申请号：US15453037
申请日：2017-03-08
申请人： NGK INSULATORS, LTD.
发明人： Kosuke Monna , Taku Okamoto , Takayuki Sakurai , Noriko Hirata
摘要： 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 sum of change amounts of an electromotive force in a time-variable profile thereof 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 during 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.
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公开(公告)号：US10545072B2
公开(公告)日：2020-01-28
申请号：US15869507
申请日：2018-01-12
申请人： NGK INSULATORS, LTD.
发明人： Kosuke Monna , Taku Okamoto
摘要： A method of diagnosing a degree of degradation of a catalyst located along an exhaust path of an internal combustion engine, and oxidizing or adsorbing a target gas included in an exhaust gas and including at least one of HC and CO is disclosed. The method includes: a) determining whether an oxygen concentration of the exhaust gas is in a range of 15% to 20% or whether the oxygen concentration is 10% or more and varies in a range of ±2% or less of a predetermined value in a predetermined period of time; and b) diagnosing whether the catalyst is degraded when criteria in the step a) are satisfied. The step b) is performed by comparing a diagnostic indicator value calculated using an output value from a target gas detection component provided at a location downstream from the catalyst and a threshold corresponding to temperature of the catalyst.
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公开(公告)号：US10527569B2
公开(公告)日：2020-01-07
申请号：US15367334
申请日：2016-12-02
申请人： NGK INSULATORS, LTD.
发明人： Taku Okamoto , Yuki Nakayama , Kosuke Monna , Osamu Nakasone
IPC分类号： G01N27/02 , G01N27/407
摘要： Provided is a method of suitably judging necessity of a recovering process carried out on a mixed-potential gas sensor based on an extent of reversible deterioration occurring in a sensing electrode. The method includes the steps of: (a) performing impedance measurement between a sensing electrode exposed to a measurement gas and a reference electrode exposed to a reference atmosphere, which are provided in the gas sensor; and (b) judging necessity of a recovering process based on electrode reaction resistance or a diagnosis parameter correlating with the electrode reaction resistance wherein the electrode reaction resistance and the diagnosis parameter are obtained based on a result of the impedance measurement. The two steps are intermittently or periodically repeated during use of the gas sensor, and it is judged that a recovering process is necessary when the judge parameter satisfies a predetermined threshold condition in the step (b).
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公开(公告)号：US10480385B2
公开(公告)日：2019-11-19
申请号：US15673766
申请日：2017-08-10
申请人： NGK INSULATORS, LTD.
发明人： Taku Okamoto , Yoshinobu Nakada , Kosuke Monna
IPC分类号： F01N13/00 , B01D53/94 , G01N27/406 , G01N27/407 , B01D53/30 , G01N27/419 , F01N3/20 , F01N3/10 , F01N3/021
摘要： A apparatus 70 for measuring combustible-gas concentration includes an electromotive force acquisition section 75 configured to acquire information about an electromotive force of a mixed potential cell 55 while a detection electrode 51 is exposed to a target gas, an oxygen concentration acquisition section 76 configured to acquire information about oxygen concentration pO2 in the target gas, and a control section 72. The control section 72 derives combustible-gas concentration pTHC in the target gas from the acquired information about the electromotive force EMF, the acquired information about the oxygen concentration pO2, and the relationship represented by formula (1): EMF=α loga(pTHC)−β logb(pO2)+B (1) where α, β, and B each represent a constant, and a and b each represent any base (provided that a≠1, a>0, b≠1, and b>0).
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公开(公告)号：US10125657B2
公开(公告)日：2018-11-13
申请号：US15454083
申请日：2017-03-09
申请人： NGK INSULATORS, LTD.
发明人： Kosuke Monna , Taku Okamoto , Takayuki Sakurai , Noriko Hirata
摘要： 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.
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公开(公告)号：US11274592B2
公开(公告)日：2022-03-15
申请号：US16594240
申请日：2019-10-07
申请人： NGK INSULATORS, LTD.
发明人： Osamu Nakasone , Kosuke Monna
摘要： A catalyst deterioration diagnosis device includes: a unit configured to obtain a temperature of a catalyst; a unit configured to obtain a sensor output from a gas sensor disposed between the catalyst and an exhaust port; and a unit configured to determine the catalyst to be faulty when the temperature of the catalyst obtained when the sensor output becomes a preset evaluative output is equal to or higher than an evaluative catalyst temperature.
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公开(公告)号：US10429338B2
公开(公告)日：2019-10-01
申请号：US15686239
申请日：2017-08-25
申请人： NGK INSULATORS, LTD.
发明人： Taku Okamoto , Noriko Hirata , Yuki Nakayama , Kosuke Monna
IPC分类号： G01N27/407 , G01N27/403 , G01N27/406
摘要： A gas sensor in which an electrode is prevented from being poisoned is provided. A mixed-potential type gas sensor includes a sensor element composed a solid electrolyte. The sensor element includes: a measurement gas introduction space having an open end at a distal end and extending in a longitudinal direction; a sensing electrode provided on an inner side of the measurement gas introduction space; and a heater configured to heat the sensor element. The concentration of the gas component is determined based on a potential difference between the sensing electrode and a reference electrode, while the heater heats the sensor element so that a place having a temperature higher than the temperature of the sensing electrode and the melting point of a poisoning substance exists between the open end and the sensing electrode and the temperature decreases toward the sensing electrode.
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