| 摘要 |
PROBLEM TO BE SOLVED: To improve the reliability in abnormality diagnosis of a high pressure fuel supply system of a cylinder injection type engine. SOLUTION: Whether a condition in which a discharge amount command value of a high pressure pump exceeds a predetermined judgement value A during engine operation continues for more than a predetermined judgement time B or not is monitored to judge that an abnormality occurs in the high pressure fuel supply system if the condition in which the discharge amount command value exceeds the judgement value A continues for more than the judgement time B. Consequently, even if such abnormality that the discharge amount command value of the high pressure pump does not exceed the maximum value in a normal scope occurs, the abnormality can be detected, and, even if an output of a fuel pressure sensor becomes an abnormal value instantaneously due to noise, it is possible to avoid to judge it as an abnormality of the high pressure fuel supply system erroneously. In this case, it is preferable that the judgement time B is set to a longer time than a response delay time (time until actual fuel pressure rises up to the vicinity of target fuel pressure) of fuel pressure control at normal time when the target fuel pressure rises.
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