| 摘要 |
PROBLEM TO BE SOLVED: To diagnose the anomaly of fuel system in high accuracy which executes variable control for fuel discharging rate of a fuel pump and feedback control for fuel discharging pressure simultaneously in accordance with required fuel injecting rate of a fuel injection valve. SOLUTION: After starting fuel pressure feedback control, the diagnosis process comprises the steps of executing a primary diagnosis based on the fuel injecting rate and the fuel discharging rate (S1, S2), transferring a secondary diagnosis based on fuel pressure when a primary diagnostic result is judged at NG or the fuel discharging rate is judged to reach minimum value or maximum value (S3 to S6), and making a secondary diagnostic result be judged at NG (S9) when a state in which a deviation between target fuel pressure and actual fuel pressure is a specific value ofΔP or more lasts during a specific time of T or more (S7, S8). COPYRIGHT: (C)2004,JPO
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