Hybridization and multi-objective optimization of plug-in hybrid electric vehicles

Plug-in hybrid electric vehicles (PHEV), which share the characteristics of both a conventional HEV and an all-electric vehicle, rely on large storage batteries. Therefore, the characteristics and hybridization of the PHEV battery with the engine and electric motor play an important role in the design and potential adoption of PHEVs. In this research work, a multi-objective optimization approach is applied to compare the operational performance of Toyota Prius PHEV20 (PHEV for 20 miles of all electric range) based on fuel economy, operating cost, and green house gas emissions for 4480 combinations (20 batteries, 14 motors, and 16 engines). Powertrain System Analysis Toolkit software package automated with the Pareto Set Pursuing multi-objective optimization method is used for this purpose on two different drive cycles. It was found that 1) battery, motor, and engine work collectively in defining an optimal hybridization scheme; and 2) the optimal hybridization scheme varies with drive cycles.