Nonlinear Modeling of the VNT Pneumatic Actuator with Aero-dynamic Force

This paper describes a physical model of an industrial pneumatic actuator used to control variable nozzle turbocharger (VNT). Friction force, that causes hysteresis, is identified using Dahl friction model. Model is tested and compared with experimental results, provided by Honeywell Turbo Technologies (HTT), at different engine conditions. Aerodynamic force acting on the turbocharger is modeled and identified as a function of pressure ratio across turbine and vane angle of the VNT. Comparison between simulation results and experimental results shows the effectiveness of the proposed model.