Zhu, B., Zhang, N., Walker, P., Zhan, W. et al., "Two Motor Two Speed Power-Train System Research of Pure Electric Vehicle," SAE Technical Paper 2013-01-1480, 2013, doi:10.4271/2013-01-1480.
Method to improve the efficiency and the design of more efficient pure electric vehicle (PEV) system is a research hotspot for the automobile industry worldwide. Traditionally, PEV powertrains are dominated almost exclusively by single reducer structures in both concept and commercially available PEVs. This paper presents a novel two motor two speed pure electric power-train structure to study alternate methods for improving the operating efficiency of a typical PEV. This idea is derived from conventional power splitting transmissions to achieve motor efficiency optimization and ultimately lead to running range improvement. Through parameter matching and simulation, results demonstrated that the proposed two motor two speed PEV can realize better vehicle performance than single reducer PEV system; furthermore it can behave even better than a similar single motor two speed system.