Automotive engine control and hybrid systems: Challenges and opportunities

The design of engine control systems has been traditionally car-ried out using a mix of heuristic techniques validated by simulation and prototyping using approximate average-value models. How-ever, the ever increasing demands on passengers ’ comfort, safety, emissions, and fuel consumption imposed by car manufacturers and regulations call for more robust techniques and the use of cycle-ac-curate models. We argue that these models must be hybrid because of the combination of time-domain and event-based behaviors. In this paper, we present a hybrid model of the engine in which both continuous and discrete time-domain as well as event-based phe-nomena are modeled in a separate but integrated manner. Based on this model, we formalize the specification of the overall engine con-trol by defining a number of hybrid control problems. To cope with the difficulties arising in the design of hybrid controllers, a design methodology is proposed. This methodology consists of a relaxatio