Variable geometry turbocharger (VGT)

Fitted to the new 9-litre engine of the 8030 series and the 4.5-litre and 6.8-litre PowerTech Plus engines of the 6030 and 7030 tractors, a variable geometry turbocharger helps to improve torque and engine responsiveness/acceleration.

How it works:

Controlled by the ECU (Engine Control Unit) the VGT regulates the charge-air pressure by adjusting the vanes of the turbine according to the engine loading and operator throttle inputs.

Closing the vanes down improves the efficiency of the turbocharger and this is used especially at low rpm when power level is needed to increase fast. This makes the boost pressure rise faster than a conventional turbo.

At high power levels when there is a lot of exhaust gas you need to limit the boost pressure (sometimes done with a wastegate turbo).

When the vanes open, the efficiency of the turbo is reduced to limit maximum boost pressure.

So the variable geometry turbo gives faster boost pressure rise which provides better low-end torque response when the throttle is opened.

Advantages:

• Higher torque at low rpm – for fast acceleration
  
• Quick response to load – for pulling through tough spots easily
  
• Improved fuel economy – cuts operating costs
  
• Increased peak torque – to maintain set speeds