Energy efficiency ratio (EER) of plug-in hybrid electric vehicles in scope of plug-in hybrid electric factor (Pihef)

Although plug-in hybrid electric vehicles (PHEVs) are becoming increasingly popular, many disputes arise about their performance, like efficiency, range and emissions. Recently, a compelling approach, called Plug-In Hybrid Electric Factor (Pihef) has been introduced for PHEVs classification. Relying upon Pihef, this paper brings an analysis of a PHEV energy efficiency ratio (EER) between combined PHEV mode and HEV mode. Hereinafter, a comparison of key performance of popular PHEVs is given according to different regulations applied in the European Union and the USA, including some specifications and results of internal combustion engine (ICE) vehicles.