Pic. 2.59. VAD system solenoid valve: 1 - power on; 2 – power off; 3 - channel A (to the atmosphere); 4 - channel B (to the actuator); 5 - channel C (to intake manifold); 6 - spiral; 7 - plunger; 8 - spring
The solenoid valve switches the intake manifold vacuum path between the intake manifold and the actuator. When power is on, the valve plunger retracts and opens a passage between air passages A and B, which allows atmospheric air to enter the damper actuator. When power is off, the plunger returns forward and opens a passage between air passages B and C, which allows vacuum from the intake manifold to the damper actuator. Solenoid valve consists of solenoid, spring, plunger and filter (pic. 2.59).