Variable Geometry Turbocharger - Primary Turbocharger
| ITEM | DESCRIPTION |
|---|---|
| 1 | Oil feed |
| 2 | Coolant inlet connection |
| 3 | Exhaust inlet Coolant connections |
| 4 | Charge air outlet |
| 5 | Clean air inlet |
| 6 | Oil drain |
| 7 | Variable Geometry Turbocharger (VGT) vane actuator |
| 8 | Variable Geometry Turbocharger (VGT) vane actuator rod |
| 9 | Coolant outlet connection |
The Variable Geometry Turbocharger (VGT) is attached to the left exhaust manifold and secured to three studs on a flange on the manifold with nuts. On production, no gasket is used to seal the joint surface between the turbocharger and the manifold. In-service vehicles will require a service gasket to be fitted if the joint surface is disturbed.
A second flange on the turbocharger has three integral studs and provides for the attachment of the Diesel Particulate Filter (DPF) inlet pipe. Three nuts secure the inlet pipe to the flange studs and a gasket seals the joint between the components.
The compressor end of the turbocharger has two hose connections. The central connection provides a clean air supply from the air filter to the compressor. The second connection on the outside of the housing provides for a pipe connection from the turbocharger to the charge air radiator.
The turbocharger comprises a turbine wheel and a machined compressor wheel, sharing a common shaft which is supported on ball bearings. The application of the machined compressor wheel and the ball bearing results improved durability, reduced Noise, Vibration and Harshness (NVH) and optimized fuel economy. The turbocharger receives an engine oil supply via a pipe from the cylinder block. The pipe supplies both turbochargers with an oil supply for lubrication purposes. An oil drain pipe from the turbocharger allows oil to drain from the turbocharger into the cylinder block. The turbocharger also has a connection for the engine cooling circuit to provide the appropriate cooling efficiency of the ball bearing.
An integral bracket houses the Variable Geometry Turbocharger (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 VGT vane actuator operates a boss is rotated, which in turn moves the lever and changes rotary motion into linear motion. The lever is connected 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).