Fig. 2.59. VAD system electromagnetic valve: 1 – power on; 2 – power off; 3 – channel A (to the atmosphere); 4 – channel B (on the actuator); 5 – channel C (to the 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 the power is on, the valve plunger retracts and opens the passage between air ports A and B, which allows atmospheric air to reach the throttle actuator. When the power is off, the plunger returns forward and opens the passage between air ports B and C, which allows vacuum from the intake manifold to reach the throttle actuator. The solenoid valve consists of a solenoid, a spring, a plunger, and a filter (Fig. 2.59).