Modelling and H∞ control of diesel engine boost pressure using a linear parameter varying technique

Abstract

In this paper, a model-based boost pressure control of a turbocharged common-rail directed injected diesel engine is proposed. An advanced linear parameter varying (LPV) technique is adopted for model development and an H∞ control scheme is synthesized for control purposes. The LPV technique has an advantage in deriving a linear model from a complex non-linear system and guarantees higher linear model precision. The boost pressure model of the diesel engine is obtained as a simple second-order linear system and the parameters of the model are estimated by the LPV identification method. With the help of the LPV modelling method, the behaviour of boost pressure of the diesel engine is precisely characterized using a second-order linear model. Based on the simplified LPV boost pressure model, a robust H∞ controller is synthesized. The state-space representation is derived to follow the control design framework of an H∞ scheme, and weighting functions for improving control performance are added into the closed-loop control system. The experimental results show that the LPV model-based diesel engine boost pressure control allows better tracking performance than the production engine management system (EMS), which requires difficult calibration work.