Patent ID: 7950365

Claim:
A control apparatus for an internal combustion engine, comprising: an oil pressure regulating valve having a solenoid; a variable cam phase mechanism for changing a cam phase with respect to a crank shaft by operating the oil pressure regulating valve; and a control unit for controlling the oil pressure regulating valve, the control unit comprising: actual cam phase detecting means for detecting the cam phase by inputting a crank angle from a crank angle sensor and by inputting a cam angle from a cam angle sensor; target cam phase setting means for setting a target cam phase with respect to the crank shaft according to a drive condition; output duty calculating means for calculating an output duty which is output to a coil of the solenoid; feedback control means for calculating a control value which is output to the output duty calculating means so that the cam phase is made coincident with the target cam phase to control the cam phase with PID feedback control; coil temperature detecting means for predicting a temperature of the coil by inputting a temperature of cooling water from a cooling water temperature sensor; circuit resistance calculating means for calculating a resistance of an electric circuit which operates the oil pressure regulating valve, by multiplying the predicted temperature of the coil by a temperature gradient so as to correct a resistance of the coil; and integral term initial value calculating means for calculating a holding output duty corresponding to the output duty in a case where the cam phase is held by employing the calculated resistance of the electric circuit, the feedback control means setting the holding output duty as an integral term in a case where the integral term is initialized.