| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect abnormality of an internal combustion engine by using NOx sensors while simplifying a configuration to suppress cost increase. <P>SOLUTION: An abnormality diagnostic device of the internal combustion engine is provided with: the NOx sensor 41 provided on the downstream side of a selective reduction catalyst 25 and detecting NOx in an exhaust gas; a water-based urea solution addition control unit 33 for controlling addition of a water-based urea solution added from water-based urea solution addition devices 27, 28; and a unit 35 for determining the abnormality of the internal combustion engine for determining the abnormality of the internal combustion engine 10 on the basis of NOx values detected with the NOx sensor 41. The water-based urea solution addition control unit 33 controls the water-based urea solution addition devices 27, 28 so as to stop addition of the water-based urea solution if a diagnostic start condition is achieved. The unit 35 for determining the abnormality of the internal combustion engine determines that the internal combustion engine 10 is abnormal when a first NOx value is larger than a second NOx value corresponding to an operation condition of the internal combustion engine 10 after the addition of the water-based urea solution is stopped by the water-based urea solution addition control unit 33. <P>COPYRIGHT: (C)2012,JPO&INPIT |
