| 摘要 |
In a variable valve timing system for an internal combustion engine, a soft-landing revertive control that an electromagnetic brake is de-energized and then an angular position of a camshaft relative to a crankshaft returns to an initial position is performed by a combination of a feedback control and a feedforward control. During the revertive control, the feedback control is executed in such a manner as to temporarily halt the angular phase of the camshaft at a predetermined position, which is phase-changed by a predetermined phase angle from the initial position. After the feedback control, the operating mode is switched to a feedforward control, so as to return the angular phase of the camshaft from the predetermined position to the initial position by changing a controlled quantity or a control-signal duty cycle value for the electromagnetic brake with a predetermined time rate of change.
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