Principles Of Variable Vane Operation: Notes

WARNING: This page is about a different car, the 2018 Jaguar XE and 2017 Jaguar XE. However, it is still accessible from the selected car via links, so may be relevant.

The variable vanes in the Variable Geometry Turbine (VGT) are used to increase or decrease the exhaust gas power transfer to the turbine wheel. Adjusting the pitch angle of the vanes greatly assists the boost pressure increase in the VGT at low engine speeds. The operation of the variable vanes is controlled by the Powertrain Control Module (PCM).

As engine speed, and therefore the exhaust gas mass flow increase, the PCM increases the vane opening. This avoids the overspeed of the turbines and provide a smooth high speed operation.

The VGT actuator also provides the PCM with a feedback signal to determine the pitch angle of the vanes. This makes sure that the power transfer from the turbine wheel to the compressor wheel is within the VGT speed and boost pressure requirements.