Variable Geometry Turbocharger Vane Actuator
The Variable Geometry Turbocharger (VGT) is attached to the exhaust manifold and secured to three studs on a flange on the manifold with nuts.
An integral bracket houses the VGT vane actuator. The VGT vane actuator is connected to an eccentric lever which moves the turbine housing to adjust the position of the vanes. When the actuator operates, a boss is rotated, which in turn moves the lever and changes rotary motion into linear motion. The lever is connected to a rod attached to the outside of the turbine housing and the linear motion is converted back to rotary motion of the housing.
Operation of the VGT vane actuator is controlled by the Powertrain Control Module (PCM). The VGT vane actuator also provides the PCM with a feedback signal to determine the pitch angle of the vanes.
The variable vanes in the turbocharger improve the exhaust gas power transfer to the turbine wheel which in turn drives the compressor wheel. This greatly assists the increase in charge air pressure at low engine speeds.
For additional information, Refer to: Turbocharger in the appropriate Fuel Charging and Controls service information.