Sliding mode control for Turbocharged Diesel Engine

For modern Diesel engines, accurate fuel-air ratio AFR and Exhaust Gas Recirculation (EGR) rates control is important for manufacturers to face a more restrictive legislation levels. To fulfill the requirements, hardware devices such (EGR) and Variable Geometry Turbochargers (VGT) valves have been introduced, and sophisticated control algorithms were designed. The main objective of the air path controller is to regulate in the intake manifold the AFR ratio and the EGR fraction rates to their desired values. Earlier EGR PID controllers needed a fastidious and time consuming calibration step for each engine operating point. Nonlinear control algorithms has quickly appeared as a promising way to provide an efficient air path controllers, since they don´t need a calibration step. The main drawback of such controllers is coming from the fact that they are based upon a diesel engine model which handles parameters uncertainties and signal measurements errors, that affects the control performance. In this paper we propose a novel control scheme for controlling the diesel engine air path. Control design is carried out under the sliding mode framework. The proposed controller has been tested on the Jankovic Tubocharged Diesel Engine (TDE) model. To demonstrate the robustness of the proposed controller, simulation results showing the tracking of the compressor flow W_c and the exhaust manifold pressure p₂ variables are presented.