| 摘要 |
PROBLEM TO BE SOLVED: To accurately determine a fault of a filter which collects PMs even if a rising time of an output of a PM sensor is changed by an idle stop function.SOLUTION: A filter 4 which collects PMs in an exhaust gas is arranged in an exhaust passage 3 of an engine 2, and a PM sensor 6 for detecting an amount of PMs is arranged at a downstream side rather than the filter 4. The PM sensor 6 comprises a sensor element in which a pair of electrodes are arranged on an insulated base board, the electrode are made conductive when the PMs equal to or larger than a prescribed amount are adhered at the sensor element, and an output rises. An ECU 7 estimates a rising time of the PM sensor 6 in the case that a fault DPF is used as a DPF 4. The ECU 7 measures an engine stop time by an idle stop function, and corrects the estimated rising time so that the time is delayed as the stop time becomes long. Then, the ECU determines a fault and normality of the DPF 4 on the basis of determination whether or not an actual rising time of the PM sensor 6 precedes or succeeds the corrected estimated rising time. |
