| 摘要 |
PROBLEM TO BE SOLVED: To diagnose abnormal condition of a high pressure fuel system for an internal combustion engine in an early stage and with high accuracy, and further specify the abnormal portion of the high pressure fuel system. SOLUTION: This diagnostic device for the cylinder injection type internal combustion engine includes: an injection correction amount calculation means 302 calculating the injection correction amount so that a detected air-fuel ratio is set to a target air-fuel ratio; a fuel injection valve control means 202 controlling a fuel injection valve by the amount of fuel injected corrected based on the injection correction amount; a discharge correction amount calculation means 305 calculating the discharge correction amount so that detected fuel pressure is set to target fuel pressure; a fuel pump control means 203 controlling a fuel pump by a discharge rate corrected based on the discharge correction amount; a fuel pressure value shift means 204 shifting a detected fuel pressure value until the injection correction amount is converged to a constant amount within a predetermined range when the injection correction amount gets out of the predetermined range; and an abnormal condition determination means 306 determining whether or not one of the fuel pump, the fuel injection valve and a fuel pressure sensor is abnormal based on the discharge correction amount before starting and after finishing shifting of the fuel pressure value and the injection correction amount before starting shifting of the fuel pressure value. COPYRIGHT: (C)2011,JPO&INPIT
|
