Patent ID: 7014167

Claim:
A control apparatus of an electromagnetic valve having a valve body functioning as an intake valve or an exhaust valve of an internal combustion engine and an electromagnet affecting an electromagnetic force to an armature provided on the valve body for displacing the valve body between a first position and a second position, the control apparatus comprising: a controller which determines a force affecting the valve body when displacing the valve body from the first position to the second position and a state quantity of the valve body varying in accordance with the force affecting the valve body, determines a target value of the force affecting the valve body or determines a target value of the state quantity of the valve body varying in accordance with the force affecting the valve body, and controls the electromagnetic force of the electromagnet for attracting the armature toward the first position based on a deviation between the determined force and the target value of the force, or controls the electromagnetic force of the electromagnet for attracting the armature toward the first position based on a deviation between the determined state quantity and the target value of the state quantity, so that the deviation is minimized, when the valve body is displaced form the first position to the second position, wherein the valve body is opened and closed by an elastic force of a spring in addition to the electromagnetic force and the controller determines the state quantity of the valve body varying in accordance with a sum of the forces affecting the valve body when displacing the valve body from the first position to the second position based on the elastic force of the spring as the target value, the controller performs a feedback-control of the electromagnetic force based on the deviation, and the controller determines a feedback gain when performing the feedback-control of the electromagnetic force based on a distance of an air gap between the armature and the electromagnet, wherein the target value of the state quantity of the valve body is a state quantity at a time when the valve body is freely vibrated based on an elastic force of the spring affecting the valve body.