Patent 7163162 was granted and assigned to Hitachi on January, 2007 by the United States Patent and Trademark Office.
A fuel-injection valve includes a fuel-injection hole, a valve element and a valve seat for opening and closing the fuel-injection hole, a force-applying member for applying force to the valve element in a direction of motion of the valve element, and a drive unit for applying force to the valve element in the direction opposite to that of the force applied by the force-applying member; wherein a secondary oscillation system, which interacts with a primary oscillation system including the valve element and the force-applying member, is added to the primary oscillation system, and the phase angle of force applied to the primary oscillation system by the secondary oscillation system is also staggered from that of force applied to the primary oscillation system, which is other than the force applied to the primary oscillation system by the secondary oscillation system, whereby the bouncing of the valve element during opening and closing of the valve is reduced, which in turn makes it possible to achieve very accurate fuel-injection control.