PURPOSE: To ensure a seal force only through pulse-form energization in a closed state by a method wherein after OFF-energization through which a coil is caused to perform operation to close a pilot solenoid valve is carried out, OFF-energization is effected again after closing of a main value subsequently to closing of the pilot solenoid valve.
CONSTITUTION: In a latching type pilot solenoid valve 12, even under a closed state, a force generated by the magnetic flux of a permanent magnet 22 is exerted on a plunger valve body 14 in an opening direction, namely, in a direction in which the plunger body 14 is pulled off from a valve seat 15. A press force applied on the valve seat 15 of the plunger valve body 14 is weakened by an amount equivalent to the force exerted on the plunger valve body. When, under the closed state, OFF-energization is applied on a coil 28 again, a force in a direction in which the plunger valve body 14 is pulled away from the valve seat 15 by means of the permanent magnet 22 is erased and a new press force is exerted on the plunger valve body 14. This constitution causes the plunger body 14 to reliably seat the valve seat 15 and ensurance of a reliable seal force for the valve seat 15.
ANDO TOMOAKI
MASUOKA KENTARO
KATAOKA SHUICHI
YAMADA ETSUSHI
MIYATA MASANORI
NIPPON DENSO CO