| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a NOx cleaning device provided with a supply device for an exhaust gas reducing agent in the upstream side of a reducing catalyst provided in the exhaust path of an internal combustion engine, for detecting a failure of sensors of NOx, NH<SB POS="POST">3</SB>, temperature or the like provided in the exhaust path, and maintaining performance of the NOx cleaning device by supplying a proper amount of reducing agent even when a failure of the sensor is detected. <P>SOLUTION: The control device of the NOx cleaning device is provided with: a NOx sensor 21 arranged in the downstream side of a NOx catalyst 11; a first NOx cleaning performance calculation means 33 for calculating the NOx cleaning performance using the NOx catalyst 11 on the basis of a signal from the NOx sensor 21; a second NOx cleaning performance calculation means 37 for calculating the NOx cleaning performance using the NOx catalyst 11 on the basis of the NOx emissions from the internal combustion engine; and a determining means 39 for determining the failure of the NOx sensor 21 by comparing calculation result of the first NOx cleaning performance and that of the second NOx cleaning performance with each other. When the failure is determined, the amount of the reducing agent to be supplied is calculated on the basis of the cleaning performance calculated by the second NOx cleaning performance calculation means 37. <P>COPYRIGHT: (C)2012,JPO&INPIT |
