Idle speed control for GDI engines using robust multirate hybrid command governors

In this paper we present an idle speed controller for automotive GDI engines. The idle speed control problem is formalized as a robust constrained optimal control problem for a hybrid model of the GDI engine. The cost to be minimized is fuel consumption. A sub-optimal robust controller is obtained by using the Command Governor methodology for a discrete-time relaxation of the hybrid model, which describes the multirate nature of the engine input signals. Simulation results of the hybrid closed-loop system are presented.