Abstract: A valve timing control system for an internal combustion engine is provided which is capable of ensuring reliable holding of a valve by an actuator, and attaining energy saving by efficient operation of the actuator. The valve timing control system controls valve-closing timing of a valve opened by a cam provided on a camshaft, by temporarily holding the valve. A response delay of the actuator is predicted as a response delay prediction value. Output timing is set in which a drive signal for driving the actuator is output, according to the predicted response delay prediction value. Holding timing is controlled in which the valve is held by the actuator, by outputting the drive signal to the actuator, based on the set output timing.

Abstract: A controller for an electromagnetic actuator comprises a pair of spring acting in opposite directions, and an armature coupled to a mechanical element. The armature is connected to the springs and held in a neutral position given by the springs when the actuator is not activated. The actuator includes a pair of electromagnets for driving the armature between two end positions. The controller includes voltage application means for applying voltage to an electromagnet providing one end position for a first predetermined period so as to attract the armature to the end position. The controller also includes a peak current detector for detecting the peak of current flowing through the electromagnet in the first predetermined period. In accordance with the peak value, a decision means decides the application period of voltage that is to be applied to the electromagnet after the first application period has elapsed.

Abstract: A controller for an electromagnetic actuator comprises a pair of springs acting on opposite directions, and an armature connected to the springs. The armature is held in a neutral position given by the springs when the armature is not activated. The actuator also comprises a pair of electromagnets for driving the armature between two end positions. In response to a release of the armature held in one of the end positions, the controller applies brake to the armature according to a load condition of the armature. In high-load conditions, the valve can surely be opened without additional electric power. In low-load conditions, the armature is prevented from colliding with a yoke of the electromagnet. The application of brake includes over-excitation operation, flywheel operation and suspension of power supply. In the over-excitation operation, voltage is applied to the electromagnet corresponding to one of the end positions from which the armature is released for a first period.

Abstract: An electromagnetic valve controller estimates a dead time based on predetermined parameters. A dead time for the current cycle is determined based on the estimated dead time. The controller measures a dead time in the previous cycle. The controller determines a deviation between the dead time measured in the previous cycle and the dead time estimated in the previous cycle. The deviation is added to the dead time estimated in the current cycle to determine the dead time for the current cycle. The controller further determines a target de-energization timing indicating when to execute a valve timing command, based on predetermined parameters. The dead time determined for the current cycle is offset or subtracted from the target de-energization timing to determine an actual de-energization timing. An electromagnet of the valve is de-energized in accordance with the actual de-energization timing.

Abstract: In an alternate energization process for alternately energizing a valve closing electromagnet and a valve opening electromagnet periodically, one of the valve opening electromagnet and the valve closing electromagnet is de-energized and thereafter the other electromagnet is de-energized at a time delayed by a predetermined time Toff. The alternate energization process is finished when the displaced position of a valve head which is detected by a displacement sensor has reached a predetermined position Vinit while the valve opening electromagnet is being energized. Thereafter, the valve opening electromagnet is continuously energized to seat the valve head in a closed position (initial position) from the time when the displaced position of the valve head has reached a predetermined position Vstart.

Abstract: An electromagnetic valve unit in an internal combustion engine is controlled by determining a difference between the output of a displacement sensor when a valve head is in an open position and the output of the displacement sensor when the valve head is in a closed position in each period of an opening and closing action of the valve head. The difference corresponds to a full displacement of the valve head between the open position and the closed position.

Abstract: An electromagnetic actuator is equipped with two springs which act in opposite directions, and an armature that is connected to the springs and is supported in an unactivated state in a neutral position provided by the two springs. The armature is coupled to a mechanical element such as a valve of an engine. The actuator includes a pair of electromagnets that drive the armature between a first terminal position and a second terminal position, and a power supply device that controls the voltage supplied to the electromagnet attracting the armature to a constant voltage when the armature is driven from one of the terminal positions to the other terminal position. The voltage supplied to the electromagnets is maintained at a constant value and the larger current flows in the larger is the gap between the armature and the yoke and smaller is the counter electromotive force.

Abstract: An electromagnetic valve unit in an internal combustion engine is controlled by determining a difference between the output of a displacement sensor when a valve head is in an open position and the output of the displacement sensor when the valve head is in a closed position in each period of an opening and closing action of the valve head. The difference corresponds to a full displacement of the valve head between the open position and the closed position.

Abstract: A control system for an internal combustion engine is configured to suitably control the operation of electromagnetically driven intake valves and/or exhaust valves upon start-up of the engine for reducing the output current of a battery and suppressing a reduction in output voltage at minimum, thereby accurately operating the electromagnetically driven valves. The control system is operated such that when an ignition switch is turned on, the operation of a starter is prohibited and initial attraction for intake valves and exhaust valves is sequentially performed in such a manner that the attracting operations for the valves are not overlapped to each other; and after the initial attraction for all the valves is completed, the operation of the starter is permitted and the start-up of the engine is performed.

Abstract: A control apparatus for an electromagnetic actuator for driving a mechanical element by using an electromagnetic coil. The control apparatus includes a circulation circuit for circulating current to be supplied to the electromagnetic coil, a capacitor provided in the circulation circuit and to be charged by the current flowing through the circulation circuit, and a unit for, when the current supplied to the electromagnetic coil is stopped, forming a discharge path for discharging the capacitor and flowing current to an opposite direction through the electromagnetic coil. The current supplied to the electromagnetic coil is charged in the capacitor, then when the current having been supplied to the electromagnetic coil is stopped, the electric charge thus accumulated in the capacitor is discharged thereby to flow current to the opposite direction through the electromagnetic coil.

Abstract: A valve operating system in an internal combustion engine, that can be readily assembled and installed on the engine, including a casing coupled to an upper surface of a cylinder head, an armature, a pair of electromagnets for exerting electromagnetic forces on the armature in directions of opening and closing of an engine valve, and a pair of resilient means for biasing the engine valve in the opening and closing directions, respectively, and for retaining the armature at a predetermined neutral position by cooperation with each other during deenergization of both the electromagnets. The resilient means for closing the engine valve is mounted between a retainer fixed to the valve stem and a fixed position on the cylinder head, and the electromagnets are fixed within the casing which is constructed so that an upper portion of the stem can be inserted into the casing.