Patent ID: 6920029

Claim:
A control method for an electromagnetic actuator for the control of a valve of an engine from an abutment condition, in which abutment condition an actuator body actuating the valve and disposed to move between two electromagnets is maintained in abutment against a first excited electromagnet and against the action of at least one elastic body; in order to bring the actuator body into abutment against a second electromagnet, the first electromagnet is de-excited and the second electromagnet is subsequently excited, the method comprising the steps of measuring during the stage of de-excitation of the first electromagnet a mean value of the disturbance force acting on the valve; calculating the excitation parameters of the second electromagnet as a function of the mean value of the disturbance force acting during the stage of de-excitation of the first electromagnet; and on the basis of the mean value of the disturbance force acting on the valve during the de-excitation stage of the first electromagnet, estimating the value of the disturbance force (F d ) up to the excitation of the second electromagnet: wherein the excitation parameters of the second electromagnet are calculated in order to provide the actuator body with the mechanical energy that it lacks in order to reach the position of abutment against the second electromagnet with a substantially zero speed of impact; the actuator body is provided with the energy dissipated during the displacement between the position of abutment against the first electromagnet and the position of abutment against the second electromagnet; and wherein the excitation parameters of the second electromagnet are calculated by assuming that the work performed by the second electromagnet offsets the work (L d ) performed by the disturbance force (F d ) according to the following equation: α · L ⁢ ⁢ d = ∫ X O ⁢ ⁢ N X cos ⁢ ⁢ t ⁢ F m ⁢ ( x , φ 2 ⁢ ( x ) ) + ∫ X cos ⁢ ⁢ t X 2 ⁢ F m ⁢ ( x , ϕ 2 ) in which: L d is the work performed by the disturbance force (F d ); F m is the force generated by the second electromagnet; α is a control parameter; x is the position of the actuator body; Φ 2 is the magnetic flux of the second electromagnet; φ 2 is the constant value of magnetic flux with which the second electromagnet normally operates; X on is the position of the actuator body, at which the second electromagnet is activated; X 2 is the final position of the actuator body, at which the actuator body is in abutment against the second electromagnet; X cost is the position of the actuator body, at which the second electromagnet reaches and maintains the magnetic flux value (φ 2 ).