Powertrain architectures of electrified vehicles: Review, classification and comparison

Increasingly stringent regulations and customers׳ demand for high fuel economy led to rapid developments of distinct alternative powertrain solutions, especially electrified vehicles. Fusion of electric machines into powertrain greatly diversifies powertrain architectures and enriches means to save energy. In this review work, conventional classification of hybrid electric vehicle (Series, Parallel and Power-split HEVs) is expanded to all electrified vehicles (xEV) by including Pure Electric Vehicle (PEV) as the fourth primary type of electrified powertrain architecture; In addition, electrification level of powertrain is analyzed and incorporated into new classification method as the second index; different variants of PEV, Series, Parallel and Power-split HEVs are presented with corresponding patents or products; more complex electrified powertrains are also illustrated by decomposing them into two or more of the four fundamental types and sub-types. This review work is based on comprehensive and up-to-date summary of current development in this field.