Functional decomposition in a vehicle control system

The introduction of electronic controls in vehicles has lead to ever increasing improvements in automotive performance in the areas of drivability, fuel economy, emissions, and safety. As new technologies emerge and are introduced on vehicles, the need for more sophisticated control solutions to coordinated the new technologies increases. The level of complexity on today´s vehicles is at a point where vehicle system level hierarchical controls are required to manage the interaction of the various complex subsystems. A method for determining the allocation of the control functions within the hierarchy is presented and demonstrated for an integrated starter-generator hybrid electric vehicle. An effort is also made to maintain generic definitions of the functional interfaces within the hierarchy in order to facility reusability of the architecture with future vehicle technologies.