| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission purifier for an internal combustion engine capable of preventing the erroneous determination of the deterioration of an exhaust purifier catalyst caused by an exhaust gas flow rate that causes the lowering of the correlation degree of an exhaust gas temperature sensed by an exhaust temperature sensor and the deterioration degree of the exhaust purifier catalyst. <P>SOLUTION: When a fuel adding process of adding fuel to exhaust gas is carried out by executing post-injection, an electronic control device 50 executes a deterioration determination process for determing the deterioration degree of the exhaust purifier catalyst based on the magnitude of deviation between a virtual catalyst floor temperature of a catalyst converter 41 calculated on the assumption that the exhaust purifier catalyst is deteriorated to a predetermined deterioration degree and the exhaust gas temperature sensed by a first exhaust temperature sensor 55. The electronic control device 50 estimates the exhaust gas flow rate in the vicinity of the first exhaust temperature sensor 55. When the estimated exhaust gas flow rate is lower than a lower limit flow rate value, the deterioration determination process is inhibited. <P>COPYRIGHT: (C)2009,JPO&INPIT |
