ABNORMALITY DIAGNOSTIC DEVICE FOR OIL JET CONTROL VALVE OF INTERNAL COMBUSTION ENGINE

An object of the present invention is to provide an abnormality diagnostic device for an oil jet control valve of an internal combustion engine which is capable of improving accuracy of abnormality diagnosis for an oil jet. The abnormality diagnostic device includes: an oil jet 12 that injects oil toward a piston of an engine 2; an oil jet gallery 9 that sends oil to the oil jet 12; an oil jet valve 13 that controls flow of oil to the oil jet 12; an oil temperature and pressure sensor 31 provided upstream of the oil jet valve 13 that detects oil pressure of the oil jet gallery 9; and a control unit 14 that, in case where the engine 2 is in a fuel-cut operation state and a predetermined condition is satisfied, performs abnormality diagnosis control for determining an abnormality in the oil jet valve 13. In the abnormality diagnosis control, the control unit 14 determines that there is the abnormality in the oil jet valve 13 when a difference between oil pressure of the oil jet gallery 9 acquired by the oil temperature and pressure sensor 31 at the time when the oil jet valve 13 is opened and oil pressure of the oil jet gallery 9 acquired by the oil temperature and pressure sensor 31 at the time when the oil jet valve 13 is closed after a predetermined period of time elapses is smaller than a predetermined difference.