| 摘要 |
The electromagnetic actuator system includes a ferromagnetic circuit defining an axial space within which a ferromagnetic plate is moved. This is attached to the rod moving the valve between two extreme positions. In operation current is supplied to a coil, and the displacement of the plate and a function of elapsed time are measured. The current varies according to the position attained by the plate, ensuring that the valve reaches the end of its action at low speed. The electromagnetic actuator system for an internal combustion engine valve includes a ferromagnetic circuit defining an axial space within which a ferromagnetic plate is moved. This is attached to the rod moving the valve between two extreme positions. Springs are provided to return the valve to the mid position between the two extremes. A coil is used to apply a magnetic force to move the plate to either of the extreme positions. In operation current is supplied to the coil, and the displacement of the plate and a function of elapsed time are measured. When the displacement of the plate attains a first fraction of the full displacement, the coil is supplied with a current which is a function of time and displacement. When the displacement achieves a second fraction current is supplied according to a second time dependent function. The first fraction is between 1/2 and 1/4 , whilst the second fraction lies between the first fraction and the complete interval less 1-2 mm. |
