| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To easily detect a crack of pipes, in a device which guides exhaust pressure before and after a DPF for trapping PM to a differential pressure sensor through the pipes to detect differential pressure of the DPF, and determines an accumulation state of the PM in the DPF based on the differential pressure of the DPF. <P>SOLUTION: If no abnormality is found in pipes 3a, 3b for guiding pressure before and after the DPF 22 to the differential pressure sensor 45, pressure pulsation propagated in an exhaust passage 21 is canceled out so that amplitude of a detection value of the DPF differential pressure caused by the pressure pulsation is reduced, in the detection value of differential pressure of the differential pressure sensor 45. Any crack is found in the pipe 3a or pipe 3b, the pressure pulsation affects the DPF differential pressure to increase the amplitude of the detection value of the DPF differential pressure. By utilizing the fact, the amplitude of the detection value of the DPF differential pressure is compared with a reference value, and if the amplitude is larger than the reference value, an abnormality is determined. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
