Variable Induction Control Valve: Description and Operation

Resonance flaps are activated by the DME control unit via a solenoid, which opens the resonance flaps with help of a diaphragm valve after reaching an engine speed of 5500 rpm. The solenoid is connected with a vacuum supply tank.

The solenoid and diaphragm valve (arrow) close when the engine speed drops below 5400 rpm. The resonance flaps are closed via two spiral springs connected with the resonance flap shafts. To avoid seizure of resonance flaps (e.g. due to deposits in the intake), the solenoid is activated briefly each time the ignition is turned on. This causes the resonance flaps to move once from final stop "CLOSED" to final stop "OPEN" and back to final stop "CLOSED".