VGT- Variable Geometry Turbocharger [Video Lesson]

A VGT or VTA is a turbocharger, wherein movable vanes are replaced by conventional fixed vanes, which can change angles to control the exhaust flow on the turbine blades. 

This helps the engine control to balance the volume of air with the fuel along with the entire engine load range.

Working of VTA

The VGT or VTA consists of nozzle rings equipped with adjustable angle-changing vanes. Each vane is connected to control a ring using a lever, which reduces the thermal hysteresis and increases the positional accuracy.


The vane position or the angle is adjusted by the control ring connected to the electric positional motor via a reduction gear. The control system governs the action of the microprocessor-controlled positional motor.


The position or angle of the vanes is thus altered after comparing the feedback signals of – air pressure after the blower, and exhaust gas temperature before and after the turbocharger.

Variable Geometry Turbine


Advantages of VTA

  • Works on the entire load range of the engine
  • Eliminates the need for an auxiliary blower
  • Reduces the fuel consumption
  • Reduces exhaust smoke emission and hence air pollution
  • Reduces fouling of engine parts
  • Improves efficiency of the engine
  • Reduces soot and carbon deposits in combustion and exhaust space
  • Economical in operation
  • Lower’s CO2, Nox, and Sox emission

Watch the Video Lesson


Log in

Log in with Google

Log in with LinkedIn


Don’t have an account? Register Now