Valve timing and valve lift control mechanism for engines

A new type engine valve control system has been presented, in which both the valve lift and valve timing are controlled directly by electric motors. A mechanism of the valve timing control system is made of planetary gears. The outer gear is the timing pulley which has a timing belt driven by the crankshaft of an engine. Two planetary gears are inside of the pulley. The gears engage with the inner gear of the pulley. The center of the disc, which has centers of the planetary gear, is connected to the camshaft. Then, the crank rotation is transmitted to the camshaft, and rotations of sun gear are added to the rotations of camshaft. This means that when rotation angle of the sun gear is controlled, the phase between the inlet valve and the exhaust valve can be controlled. The lift control system is made of linear slider and ball screw. The cam shape of this system is three-dimensional. The height of the cam varies along the axis of the shaft. When the ball screw rotates, the camshaft slides in the axial direction, so that the lift of the cam varies. The control method is presented for the mechanism, in which valve phase and the lift are controlled continuously. Experimental tests have been carried out for the system.