Patent ID: 7472884

Claim:
A control unit for an electromagnetically driven valve including: a drive valve that includes a valve stem and that reciprocates between a first position and a second position in a direction in which the valve stem extends; an oscillation member which is connected to the valve stem; an elastic member which applies elastic force to the oscillation member such that the drive valve is held at a predetermined position between the first position and the second position; and a magnetic force generating device for applying electromagnetic force to the oscillation member based on electric power supplied to the magnetic force generating device, wherein the magnetic force generating device applies electromagnetic force for moving the drive valve toward the first position and electromagnetic force for moving the drive valve toward the second position, which is equal to the electromagnetic force for moving the drive valve toward the first position, to the oscillation member, if the electric power is applied to the magnetic force generating device when the drive valve is at a center position between the first position and the second position, and the predetermined position is deviated from the center position toward the first position or the second position, the electromagnetically driven valve operating by using both the electromagnetic force and the elastic force, the control unit comprising: an electric power supplying device for supplying electric power to the magnetic force generating device; a detecting device for detecting a movement amount of the drive valve; and a control device for controlling a supply of electric power to the magnetic force generating device according to one of an oscillation cycle based on the elastic force and the movement amount of the drive valve, wherein the magnetic force generating device is an electromagnet formed of a piece of coil and the control device controls an electric power supply period and an electric power supply stopped period according to the oscillation cycle based on the elastic force, and performs control such that an amount of electric power supplied to the magnetic force generating device becomes equal to a predetermined amount of electric power, when the movement amount becomes equal to a predetermined movement amount.