| 摘要 |
A valve actuating device for an internal combustion engine is operated with partial valve lift. The valve is spring biased toward a neutral central position but held in full open or closed positions by permanent magnets having associated coils. Normal activation of the valve between full open and closed positions is by activation of a coil to fully cancel the field of the associated magnet with a spring moving the valve to the other position. Partial lift operation comprises providing, with the valve in its closed position, a valve opening current to the valve opening coil to reduce the closing magnetic field but stopping the current before the valve reaches its full open position and providing a valve closing current to one of the coils to cause the return of the valve to its closed position. Two modes of partial lift operation are described: a first in which valve movement is continuous with valve opening duration substantially proportional to valve lift and a second in which the valve is moved to a stable half lift position, left in this position for an arbitrary duration, and pulled back into the closed position.
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