| 摘要 |
PROBLEM TO BE SOLVED: To provide an abnormality diagnostic device of a fuel pump, capable of detecting abnormality in an early stage. SOLUTION: Fuel pressure P is detected according to the output of a fuel pressure sensor, and the discharging amount of a fuel pump is lowered to lower the fuel pressure P to first predetermined fuel pressure P1. When the fuel pressure P is lowered to the first predetermined fuel pressure P1, the discharging amount of the fuel pump is raised again, thereby raising the fuel pressure P. Then, elapsed timeΔT2 until rising to second predetermined fuel pressure P2 is measured, and the abnormality determination of the fuel pump is carried out according to the elapsed timeΔT2 and an operation state of an internal combustion engine. Namely, predetermined time Tb decided about each operation state of the internal combustion engine is compared with the elapsed timeΔT2, thereby carrying out the abnormality determination. COPYRIGHT: (C)2009,JPO&INPIT
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