| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an abnormality determination device of a NOx sensor used for an exhaust emission control system, more accurately determining normality or abnormality of the NOx sensor. <P>SOLUTION: This abnormality determination device of the NOx sensor 52, 53 used for the exhaust emission control system for an internal combustion engine and outputting different output values according to NOx concentration, includes: a NOx concentration increase/decrease changing means changing to temporarily increase and decrease the NOx concentration in exhaust gas reaching the NOx sensor during an abnormality determination mode in a predetermined operating condition of the internal combustion engine; an elapsed time measuring means measuring elapsed time from the output condition of the predetermined first output value of the NOx sensor to the output of the predetermined second output value by the NOx sensor when the NOx concentration is changed to be increase/decreased by the NOx concentration increase/decrease changing means; and a determination means determining the normality or abnormality of the NOx sensor based on the elapsed time measured by the elapsed time measuring means and reference elapsed time. <P>COPYRIGHT: (C)2009,JPO&INPIT |
