The most common implementation is a set of several aerodynamically-shaped vanes in the turbine housing near the turbine inlet. As these vanes move, the area between the tips of them changes, thereby leading to a variable aspect ratio. Usually, the vanes are controlled by a membrane actuator identical to that of a wastegate, although electric servo actuated vanes are becoming more common.
The first production car to use these turbos was the limited-production 1989 Shelby CSX-VNT, equipped with a 2.2L Chrysler K engine . The Shelby CSX-VNT utilised a turbo from Garrett, called the VNT-25 because it used the same compressor and shaft as the more common Garrett T-25. This type of turbine is called a Variable Nozzle Turbine (VNT). Turbocharger manufacturer Aerocharger uses the term 'Variable Area Turbine Nozzle' (VATN) to describe this type of turbine nozzle. Other common terms include Variable Turbine Geometry (VTG), Variable Geometry Turbo (VGT) and Variable Vane Turbine (VVT).
The Peugeot 405 T16, launched in 1992, used a Garrett VAT25 variable geometry turbo charger on its 2.0 16v turbocharged engine.
The 2007 Porsche 911 Turbo has a twin turbocharged 3.6-litre flat six, and the turbos used are BorgWarner's Variable Turbine Geometry (VTGs). VGTs have been used on advanced turbo diesel engines for a few years and on the Shelby CSX-VNT.(only 500 Shelby CSX-VNTs were ever produced, and 1046 Peugeot 405 T16s.)
"Variable Geometry Turbocharger and Flow Rate Adjustment Method for the Same" in Patent Application Approval Process
Jul 11, 2013; By a News Reporter-Staff News Editor at Politics & Government Week -- A patent application by the inventors UESUGI, Tsuyoshi...