Control-Oriented Modeling Methodology for Turbocharged Engine Control Design and System Calibration

The purpose of this study is to develop control-oriented modeling methodology and apply to an actual control design in turbocharged spark ignition engines. A grey-box modeling approach was adapted to accelerate the system calibration time, while providing accurate system dynamics. An engine simulator based on first principles models was utilized to investigate the statistical model derivation process. A recursive least squares method with forgetting factor was employed to estimate model parameters related to turbocharger and vehicle/drivetrain behaviors, which seemed to be major factors causing delay of turbocharger system. The concept was demonstrated through its application to the actual control design, and the reliability of the proposed method was theoretically investigated. According to the model evaluation results, approximated behavior models are in good agreement with time series data yielded by the engine simulator under various transient operations. Using these behavior models, turbocharged engine torque-demand control method based on a throttle and wastegate valve was investigated. Desired torque profile in the period of turbocharged engine acceleration can be realized using the throttle and wastegate valve cooperation control.