Integrated Electro-Mechanical Transmission Systems in Hybrid Electric Vehicles

Hybrid electric vehicles are emerging as a practical solution for meeting increasingly more stringent governmental standards for fuel economy and emissions. In order to improve performance, increase efficiency, and reduce costs, there is a trend toward more integrated electro-mechanical transmission systems for advanced hybrid powertrains. This paper primarily focuses on the state-of-the-art electro-mechanical integration of hybrid transmission systems and presents a comprehensive review of various integrated powertrains including the power-split, two-mode hybrid transmission systems, and the electric variable transmission. Fundamental principles and mechanisms of operation for these integrated electro-mechanical transmission systems are presented as well.