Model-free control applied to a direct injection system: Experimental validation

This work presents the design and application of the Model-free controller with algebraic estimator and ultra local model on the common-rail high-pressure in a Direct Injection Fuel System of an internal combustion engine. In this application, the PID controller is traditionally used, but it needs different settings as modifications in the operating point occur. These changes encompass motor rotation, injection time, or torque demand. On the other hand, this paper considers only a single set of control parameters that provides good performance considering a broad range of operating points. A commercial electronic control unit (FlexECU) offering the possibility of new software development was used to implement the control algorithm and manage all engine functions. The tuning process of the controller is presented and discussed. Tests were carried out, and the results were graphically demonstrated, evidencing the easy applicability, robustness, and ability of the considered Mode-free scheme to control nonlinear systems, even facing important dynamic variations.