Patent ID: 7398751

Claim:
A control device of an engine valve comprising: a rotational phase difference-adjusting means which varies a rotational phase difference of a camshaft relative to a crankshaft to adjust operating timing of an engine valve; a crank angle detector for detecting a rotational angle of the crankshaft; a cam angle detector for detecting a rotational angle of the camshaft; a phase difference-calculating means which calculates the rotational phase difference based upon a detection value of the crank angle detector and a detection value of the cam angle detector; a learning means which learns a holding learning value as an operational signal of the rotational phase difference-adjusting means for holding the rotational phase difference; a calculating means which calculates a feedback correction amount in accordance with a difference between an actual value and a target value of the rotational phase difference; a control means which feedback-controls the actual value to the target value by operating the rotational phase difference-adjusting means with the feedback correction amount by setting the holding learning value as a reference; and an alteration means which alters the holding learning value as the reference only by a specified value on condition that the operational signal for holding the rotational phase difference is assumed to change.