| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission purifying apparatus for an internal combustion engine capable of detecting with high accuracy a degree of deterioration of a fuel addition valve, in a configuration in which an exhaust pipe includes a NOx catalyst that performs occlusion and reduction of NOx, and a fuel addition valve that adds fuel to an upstream of the NOx catalyst. <P>SOLUTION: When there is a request for detecting the degree of deterioration of the fuel addition valve equipped on an exhaust pipe, during a lean combustion period, (S10:YES), two or more times of fuel additions are continuously performed in a range of not becoming rich from the fuel addition valve (S20). When a waveform of A/F measured values of exhaust, or a waveform of estimated values of amounts of fuel additions estimated therefrom becomes stable (converged) (S30:YES), a degree of deterioration of the fuel addition valve is calculated (S50), and addition parameters are corrected depending on the degree of deterioration (S70), or a warning is issued to a driver (S80). <P>COPYRIGHT: (C)2011,JPO&INPIT |
