Patent ID: 7950623

Claim:
A valve opening and closing control apparatus comprising: a fluid control valve device that includes: a housing that forms a fluid passage communicated with a combustion chamber of an internal combustion engine; and a valve that is received in the fluid passage in an openable and closable manner; an actuator that includes: an electric motor that generates a drive force to drive the valve in a valve opening direction or a valve closing direction; and a plurality of gears that transmit the drive force of the electric motor to the valve; a first valve urging means for urging the valve in the valve closing direction; a second valve urging means for urging the valve in the valve opening direction; a valve position sensing means for sensing a current position of the valve; and a control unit that variably controls an electric power supplied to the electric motor in such a manner that a valve position, which is sensed with the valve position sensing means, coincides with a control target value of the valve, wherein: the control unit variably controls the electric power supplied to the electric motor in such a manner that the valve repeats an opening and closing movement within a predetermined valve opening degree range between a first intermediate position and a second intermediate position through a neutral position; the neutral position is located at or adjacent to a full close position, at which the valve is fully closed to close the fluid passage; an urging force of the first valve urging means is balanced with an urging force of the second valve urging means at the neutral position; the first intermediate position is displaced from the neutral position in the valve opening direction; the second intermediate position is displaced from the neutral position in the valve closing direction; when the control unit variably controls the electric power supplied to the electric motor to repeat the valve opening and closing movement of the valve, the control unit initially sets one of the neutral position and a position adjacent to the neutral position as the control target value until the valve position, which is sensed with the valve position sensing means, is located immediately before the one of the neutral position and the position adjacent to the neutral position; and the control unit thereafter changes the control target value to the first intermediate position or the second intermediate position when the control unit determines that the valve position, which is sensed with the valve position sensing means, reaches the one of the neutral position and the position adjacent to the neutral position.