Nonlinear airpath control of modern diesel powertrains: a fuzzy systems approach

In this article, an adaptive dynamic feedback linearisation (DFL) control design for the air-path system of diesel engines with uncertain parameters and external driver commands is proposed. First, the linearising control law is derived for the nominal diesel plant. It achieves tracking of suitable references (corresponding to low emissions and fuel consumption) for both the air–fuel ratio and the fraction of the recirculated exhaust gas. The engine model used for control design is formulated as a Takagi–Sugeno fuzzy model, and a fuzzy estimation algorithm is used to identify the plant parameters. Then, the identified parameters are used to adapt the controller online. The simulated diesel engine is a medium duty Caterpillar 3126B with six cylinders, equipped with a variable geometry turbocharger and an exhaust gas recirculation valve. The proposed controller design is based on the reduced third-order mean value model and implemented as a closed-form DFL control law on the full-order model. The resulting controllers, with and without adaptation, are assessed through simulations with a software-in-the-loop architecture using dSpace simulator. The adaptive controller, in particular, exhibits good control performance, ensuring global stability and tracking of output references with zero steady state offset.