Comparison of several strategies for HEV energy management system including engine and catalyst temperatures

In this paper, we investigate the benefits of considering advanced modeling of engine and after-treatment system (3-way catalyst) in the design of Energy Management System (EMS) for a parallel Hybrid-Electric light-duty Vehicle (HEV) (passenger car with gasoline engine). The evaluation is based on a comparative study of optimal control problems formulated using three distinct levels of model complexity. Starting with a single state dynamics (battery state-of-charge), successively, we consider the engine temperature and the 3-way catalyst temperature, yielding increased complexity. As is shown, the increased complexity brings only little improvement in fuel economy and emissions reduction. We provide quantitative results to assess this observation.