| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method of diagnosing a NOx sensor with high reliability. <P>SOLUTION: The method of diagnosing a NOx sensor is for a NOx sensor (15) placed behind a NOx storage catalyst (13) which stores NOx in lean stages (M1, M2) of an internal combustion engine (10) and is regenerated in regeneration stages (R1, R2) of the engine (10). The method comprises observing at least two signal values (NO1 to NO5) in NOx sensor signals (NO) at different times (T1 to T6), determining at least one of differences (D1 to D5) among the signal values (NO1 to NO5), comparing the differences (D1 to D5) with thresholds (SW1 to SW5), and outputting an error signal (FS) when the differences (D1 to D5) falls below the thresholds (SW1 to SW5). <P>COPYRIGHT: (C)2005,JPO&NCIPI |
