Patent 7225794 was granted and assigned to Mitsubishi Fuso Truck and Bus Corporation on June, 2007 by the United States Patent and Trademark Office.
Immediately before fuel pressure is increased by a pressure-increase mechanism, a pressure-increase control valve of each cylinder is opened in timing that does not overlap the timing of opening of an injection control valve, and the period of time for which the pressure-increase control valves is opened is gradually increased. As a result, it is possible to prevent the quantity of fuel consumed by the pressure-increase mechanism from rapidly increasing when the increase of fuel pressure is started.