Denso Corporation

Toshihiko Harada

Satoshi Nakamura

Kensuke Takizawa

Hiroaki Yoto

Shinya Teranishi

Hironobu Shimokawa

Hiroki Ichikawa

Eriko Maeda

Kazuki Yagi

A deterioration determination apparatus is usable with an ammonia sensor that includes an ammonia element portion that includes, a solid electrolyte, an ammonia electrode, and a reference electrode. The deterioration determining apparatus compares a first evaluation value and a second evaluation value, and determines whether deterioration has occurred in the ammonia element portion of the ammonia sensor at an evaluation time or subsequent to the evaluation time. The first evaluation value is based on a first sensor current obtained when a DC voltage is applied between the ammonia electrode and the reference electrode of the ammonia element portion at an initial time that is during an initial use period of the ammonia sensor. The second evaluation value is based on a second sensor current obtained when the DC voltage is applied between the ammonia electrode and the reference electrode subsequent to the initial period of use of the ammonia sensor.

Deterioration determination apparatus for ammonia sensor

An abnormality determination apparatus for an ammonia sensor is usable in an exhaust purification system including a catalyst, a supply apparatus, an ammonia sensor, an NOsensor, and an oxygen sensor. During a continuation period within which ammonia supply to the catalyst continues after the supply apparatus stops supply of reductant, the abnormality determination apparatus calculates the ammonia concentration on a downstream side of the catalyst as a first concentration value, based on an output of the ammonia sensor and an output of the oxygen sensor. During the continuation period, the abnormality determination apparatus calculates the ammonia concentration on the downstream side of the catalyst as a second concentration value, based on an output of the NOsensor and the output of the oxygen sensor. The abnormality determination apparatus determines presence or absence of abnormality in the ammonia sensor based on the first concentration value and the second concentration value.

Abnormality determination apparatus for ammonia sensor

Disclosed is an ammonia sensor element having a measured gas chamber, a reference gas chamber and a solid electrolyte body arranged therebetween. The solid electrolyte body has a first main surface facing the measured gas chamber and a second main surface facing the reference gas chamber. A detection electrode is formed on the first main surface. A reference electrode is formed on the second main surface. The solid electrolyte body contains a first proton conducting solid electrolyte. The detection electrode contains a second proton conducting solid electrolyte. The second proton conducting solid electrolyte has an acid strength greater than that of the first proton conducting solid electrolyte.

Ammonia sensor element

A gas sensor element having good sensitivity and responsiveness at low temperature, and a gas sensor are provided. The gas sensor element includes a solid electrolyte member made of an oxygen ion conductive ZrO-based ceramic, and a reference gas-side electrode and a measuring gas-side electrode respectively provided on a surface and the other surface of the solid electrolyte member. The gas sensor includes the gas sensor element. The reference gas-side electrode and the measuring gas-side electrode are formed so as to face each other with the solid electrolyte member interposed therebetween, and are both made of a noble metal or a noble metal alloy. A mixed layer with an average thickness of 800 nm or less is formed between the solid electrolyte member and the reference gas-side electrode. The mixed layer contains a noble metal or a noble metal alloy and a ZrO-based ceramic mixed with each other.

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Nishio, Japan

Toshihiko Harada