Abnormality diagnosis device for a sensor
AssigneeToyota Jidosha Kabushiki Kaisha
InventorsArifumi Matsumoto, Tomoyuki Kogo, Taiga Hagimoto, Kenji Furui, Akifumi Uozumi
Life of this patent
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Abstract
An incorrect or wrong diagnosis in abnormality diagnosis of a sensor is suppressed. Provided at the downstream side of an NOx selective reduction catalyst is a sensor which detects NOx and ammonia in an exhaust gas flowing out of the NOx selective reduction catalyst, and in which the NOx and the ammonia react with each other. An amount of decrease in an output of the sensor due to a reaction of the NOx and the ammonia in the sensor is calculated based on the NOx and the ammonia flowing out of the NOx catalyst, and an abnormality diagnosis of the sensor is carried out based on this amount of decrease in the output of the sensor.
Claims17
An abnormality diagnosis device for a sensor in an exhaust gas purification apparatus of an internal combustion engine, which is provided with:
- an NOx selective reduction catalyst that is arranged in an exhaust passage of the internal combustion engine and uses ammonia as a reducing agent;
- an injection valve configured to supply ammonia or a precursor of ammonia into an exhaust gas flowing into said NOx selective reduction catalyst, at a location upstream of said NOx selective reduction catalyst;
- and
- a sensor that is arranged at the downstream side of said NOx selective reduction catalyst, and configured to detect NOx and ammonia in an exhaust gas flowing out of said NOx selective reduction catalyst, with the NOx and the ammonia reacting with each other therein;
- comprising:
- a controller comprising at least one processor configured to
- estimate a concentration of NOx in the exhaust gas flowing out of said NOx selective reduction catalyst;
- estimate a concentration of ammonia in the exhaust gas flowing out of said NOx selective reduction catalyst;
- calculate an amount of decrease in an output of said sensor due to a reaction of NOx and ammonia in said sensor, based on the NOx concentration estimated by said controller and the ammonia concentration estimated by said controller;
- carry out a diagnosis of said sensor based on an output value of said sensor;
- and
- control the diagnosis in said controller based on the amount of decrease in the output of said sensor calculated by said controller.
Dependencies are inferred from the claim text.