Honda Motor Co., Ltd.

Ngk Spark Plug Company, Limited

Koichi Awano

Seiji Oya

Koji Shiotani

Tomonori Kondo

Tomohiro Wakazono

Mineji Nasu

Hiroshi Kubota

Kazuo Yanada

Atsushi Izumiura

Daisuke Sato

A gas sensor controllerstops an operation of pumping in or out oxygen that is being performed by a first pump cellin a state that the oxygen concentration (oxygen partial pressure) of a gas to be measured is equal to a status judgment reference value (20%). The gas sensor controllercalculates an oxygen pressure in a second measurement chamberon the basis of a second pump current Ip. If the oxygen pressure in the second measurement chamberis equal to a deterioration judgment reference value, the gas sensor controllerjudges that the second pump cellis in a normal state. If the oxygen pressure in the second measurement chamberis different from the deterioration judgment reference value, the gas sensor controllerjudges that the second pump cellis in a deteriorated state.

Sensor deterioration judging apparatus and sensor deterioration judging method

In a sensor diagnosis process, a controller for controlling an NOx gas sensor performs processing of changing the oxygen partial pressure in a second measurement chamber by changing the oxygen partial pressure in a first measurement chamber (S), processing of detecting a current flowing through a second pump cell before the change of the oxygen partial pressure (S), and processing of detecting a current flowing through the second pump cell after the change of the oxygen partial pressure (S). Furthermore, the controller performs processing of judging whether or not the ratio between the current values detected by the respective current detecting unit falls within an allowable range, judging that the second pump cellis in a normal state if the ratio between the current values falls within the allowable range, and judging that the second pump cellis in a deteriorated state if the ratio between the current values is out of the allowable range (Sand S).

A device for determining abnormality of a fuel supply system, which is capable of determining abnormality of the fuel supply system including a fuel pressure sensor more accurately. A device for determining abnormality of a fuel supply system that has a fuel pressure sensor for detecting pressure of fuel in an accumulator as detected fuel pressure calculates a predetermined normal-time fuel pressure indicative of pressure fuel in the accumulator which is to be detected when the system is normal, according to a fuel flow rate relationship parameter indicative of a relationship between an inflow fuel amount parameter indicative of an amount of fuel flowing into the accumulator and an outflow fuel amount parameter indicative of an amount of fuel flowing out of the accumulator, and determines abnormality of the fuel supply system based on a result of comparison between the detected fuel pressure and the calculated normal-time fuel pressure.

Abnormality-determining device and method for fuel supply system, and engine control unit

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Wako, Japan

Koichi Awano