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Bypass control valve, V6

Bypass control valve, V6


Accelerator depressed

When the turbocharger is working, pressure builds up in the turbocharger pressure pipe, throttle body and intake manifold. As long as the throttle butterfly is open, there is pressure on both sides of the bypass control valve diaphragm which is held closed partly by the force of the integral spring and partly by the pressure in the intake manifold.

When the accelerator is released


When the throttle butterfly closes, a vacuum is quickly created in the intake manifold due to combustion while the pressure before the throttle butterfly remains the same.

To prevent the pressure in the inlet manifold increasing too quickly, which will cause jerking, the excess pressure before the throttle butterfly valve must be released when the butterfly reopens.

Because of the vacuum in the intake manifold, a vacuum is also created on the spring side in the bypass control valve. The vacuum causes the valve to open and the pressure from the pressure pipe and throttle body escapes into the intake hose.