Method of controlling an electric valve drive device and a control system therefor

A control system for an electric valve drive device for moving a poppet valve having a valve stem in an internal combustion engine, said device having a moving coil mounted to the valve stem and a magnet fixed to a stationary member so that magnetic flux may be generated in a direction perpendicular to winding of the moving coil, said control system comprising:

• a plurality of sensors for detecting working conditions of an engine;
• means for discriminating the working conditions of the engine based on an output signal from said sensors;
• a valve timing lift pattern memory which has optimum valve timing and lift corresponding to the working conditions of the engine to generate an optimum valve position signal;
• a valve position detector for detecting actual valve position with respect to a stationary member to generate an actual valve position signal;
• a corrector for correcting the actual valve position signal to represent closed position any time when the valve is closed;
• and
• a comparator for comparing the actual valve position signal with the optimum valve position signal to apply an electric current to said moving coil to move the valve up and down so that difference may not occur between said two signals.