What is a VNT?
A Garrett® VNT turbocharger works by adjusting the gas throat section at the inlet of the turbine wheel in order to optimize turbine power with the required flow velocity.
At low engine speed and small gas flow, the turbocharger reduces the throat section, increasing turbine power and boost pressure. At full engine speed and high gas flow, the VNT turbocharger increases the throat section, avoiding turbocharger overspeed and maintaining the booster pressure required by the engine.
The throat section modulation can be controlled directly by the compressor pressure through the use of a pressure actuator, or by the engine management system using a vacuum actuator. To modify the throat section, VNT Multivane models use a mobile multivane system composed of a number of vanes which rotate relative to the turbine wheel axis.
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