Patent ID: 7387289
Filing Date: 2008-06-17
Classification: F02D,G05D

Abstract:
1. A method for driving a solenoid proportional control valve for a common rail system, said valve being arranged for flow rate control of fuel supplied from a feed pump to high-pressure plungers for feeding a high-pressure fuel to a common rail, said flow rate control being performed by regulating a driving current applied to a coil of a drive solenoid of said solenoid proportional control valve, whereby the flow rate control is performed in accordance with a desired rail pressure of the common rail, wherein said method comprises: detecting whether or not an operating condition liable to cause hysteresis in operation of said solenoid proportional control valve exists; intermittently conducting a temporary increase in electric energy imparted to the coil to instantaneously boost a driving force of the drive solenoid when it is determined that an operating condition liable to cause hysteresis in the operation of said solenoid proportional control valve exists, wherein said temporary increase in electric energy produces an energy level that is greater than a normal operating energy level of said solenoid proportional control valve; and temporarily discontinuing control for said temporary increase in electric energy imparted to the coil when a difference between the desired rail pressure of the common rail and an actual rail pressure of the common rail is less than a prescribed value, said difference being less than said prescribed value indicating that said solenoid proportional valve is operating smoothly, wherein detecting whether or not an operating condition liable to cause hysteresis in operation of said solenoid proportional control valve exists further comprises considering whether: