Control strategy optimization for an hybrid parallel powertrain

Performances of hybrid vehicles in terms of fuel consumption are strongly related to their control strategy. First studies of this problem deal with instantaneous optimization algorithms (G. Pagnelli, 1999; J. Seiler and D. Schroder, 1998; K. Yamaguchi et al., 1996), designed for real time application. Second studies are based on global optimization algorithms (S. Delprat et al., 1999; S. Rimaux et al., 1999). They outperform instantaneous optimization results, but require a lot of computing time and it seems hard to derive a real time strategy from them. The paper focuses on a control strategy issue applied to the described example of a hybrid parallel single shaft architecture. A global optimization algorithm based on optimal control theory is presented. The results obtained with the optimal theory outperform the ones obtained by local and/or global strategies. A very interesting point is that this method can be easily used for real time application.