| 摘要 |
<P>PROBLEM TO BE SOLVED: To perform abnormality diagnosis for low-pressure fuel system during operation of high pressure pump in a fuel supply system having a low-pressure pump and the high pressure pump. <P>SOLUTION: A diagnosis device calculates a fuel pressure F/B (Feed Back) correction value for matching the fuel pressure of the high-pressure system detected by a fuel pressure sensor 32 with a target fuel pressure and performs F/B control of high-pressure side fuel pressure for correcting a discharge amount of the high-pressure pump 14 (energizing period of a fuel pressure control valve 23) by using the fuel pressure F/B correction value. During performance of the high-pressure side fuel pressure F/B control, the diagnosis device performs low-pressure pump discharge amount forcibly changing control so as to forcibly change (e.g. to increase) the discharge amount of the low-pressure pump 12. Based on a control state of the high-pressure side fuel pressure F/B control (e.g. the fuel pressure F/B correction value) when the low-pressure pump discharge amount forcibly changing control is performed, the diagnosis device determines the presence or absence of abnormality of the low-pressure fuel system (e.g. low-pressure pump 12, fuel piping 13, a pressure regulator 15, the control system of the low-pressure pump 12, and the like). <P>COPYRIGHT: (C)2012,JPO&INPIT |
