Hybrid powertrain design using optimal control strategies

The urgent need of CO₂ emissions saving leads automakers to develop more efficient powertrains. The present work compares different electric hybridizations to identify key guidelines to design efficient systems. The optimal energetic performances of different powertrain architectures (series, parallel and combined) are calculated by using optimal control strategies and dynamic programming. The aim is to point out the limiting factors of a given architecture and to define how electric power components should evolve to achieve a better global efficiency of the system. The battery capacity influence on CO₂ saving is discussed. The distribution of electric loads is presented for different INRETS driving cycles. The influence of the electric machine efficiency on regenerative braking and internal combustion engine working points optimization is analysed. This work leads to technical specifications to choose an optimal architecture and to size the electrical components.