Patent ID: 9726104
Date: 2017-08-08
CPC Classifications: F02D,F04B,Y10T

Claim:
1. A control method of a magnetic solenoid valve for a high pressure fuel pump which comprises: a plunger rod biased by a spring; and an electromagnetic solenoid device which generates an electromagnetic force in a direction opposite to a biasing force of the spring corresponding to an electric current which flows in a solenoid, and is configured to control an operation of an inlet valve, wherein the inlet valve is provided adjacent to the plunger rod and is located on a pressurizing chamber side from an opening portion of a valve housing, and wherein the plunger rod is moved to a first position or a second position, thus respectively causing the plunger rod to be engaged with the inlet valve or causing an engagement between the plunger rod and the inlet valve to be released, the method comprising steps of: applying a first current to the solenoid, the first current generating a first electromagnetic force which is stronger than the biasing force of the spring and moves the plunger rod from the first position to the second position; subsequent to applying the first current, applying a limited current to the solenoid, the limited current having a value of zero or close to zero, and the plunger rod being kept around the second position during at least part of a compression stroke of the high pressure fuel pump; and subsequent to applying the limited current, applying a second current to the solenoid in a suction stroke of the high pressure fuel pump in which the inlet valve moves in an opening direction, the second current generating a second electromagnetic force which reduces energy of the plunger rod moving to the first position in the suction stroke, wherein a maximum value of the first current is larger than a maximum value of the second current, and wherein the second current decelerates the movement of the plunger rod after the inlet valve starts to move towards the pressurizing chamber side by a differential pressure during the suction stroke of the high pressure fuel pump and (i) before the inlet valve separated from the plunger rod strikes a stopper or (ii) before the plunger rod strikes the inlet valve.