Wastegate: Description and Operation

Air Bypass Valve:

PURPOSE
Bypasses air from the intake air duct before the turbocharger to relieve high pressure and reduce vibration noise during deceleration.

LOCATION
In the outlet pipe of the turbocharger near the turbine assembly.

OPERATION
When the throttle plates close suddenly during high speed and heavy load, air vibration occurs between throttle plates and turbocharger because of pressurization caused by compressor wheel rotation. To reduce this noise, air duct pressure is released before the turbocharger when intake plenum vacuum is 9.8 in Hg (250 mmHg) or more.