A Novel Architecture of Multimode Hybrid Powertrains for Fuel Efficiency and Sizing Optimization

Abstract

Hybrid powertrains have widely been developed as eco-friendly system and commercialized in the passenger vehicle market with clear benefits over conventional powertrains. Accordingly, there have been various research topics on architectures of hybrid power systems to further improve the system performance ability and sizing optimization for the packaging and production cost reduction. In this study, a novel multimode power split hybrid architecture has been suggested, which is based on multiple driving modes such as input- and output-power split and parallel hybrid modes in order to achieve fuel efficiency improvement and sizing optimization. The performance ability and sizing aspects of the invented system have been analyzed in comparison with Toyota Hybrid System (THS), which is a kind of typical power split hybrid architecture. The fuel efficiency of the suggested system has been compared by a backward-facing simulation with Dynamic Programming (DP) for representative driving test cycles from Environmental Protection Agency (EPA). In terms of the component sizing, the maximum torque and speed variation trends of motors have been analyzed according to the velocity variation. In the simulation and analysis results, the invented system shows opportunities to improve fuel efficiency with multiple driving modes and to reduce component sizing of power electronics which is related to the production cost reduction as well as the vehicle packaging space minimization.

Keywords

• Hybrid power systems
• dynamic programming
• fuel efficiency
• power split hybrid transmission