Abstract
Hybrid electric vehicle (HEV) traction systems are the most promising technologies being characterized by high performance, high fuel efficiency, low emissions and long operating range. Significant improvements can be achieved equipping transmissions with variable transmission ratio such as power-split transmission and a compound power-split electric continuously variable transmission (eCVT). These systems have been introduced to improve vehicle global efficiency since they can maximize the efficiency in different operating conditions. Optimal design and control of these systems leads improvements in vehicles performance and mathematical models, which support the preliminary design phase, can play a key role in this field. In this work, the internal power circulations of “four-port-mechanical-power split device are determined through a dynamic analysis.” Finally, the efficiency of the compound transmission is analytically evaluated, assuming that the overall losses are linked to the eCVT variator.
Highlights
The adoption of electrified systems is one of the biggest challenge of the automotive industry and this has led to many research activities dealing with their development and criticalities, [1,2,3]
Hybrid electric vehicles (HEV) are often equipped with multiple power sources so transmissions with multiple inputs are often employed as the power split transmissions (PS-CVT) [6]
This section deals with the necessary conditions to understand at priori which power flows will occur in the power-split device
Summary
The adoption of electrified systems is one of the biggest challenge of the automotive industry and this has led to many research activities dealing with their development and criticalities, [1,2,3]. Hybrid electric vehicles (HEV) work in several operating modes: fully electric; charge sustaining; stationary condition; braking regeneration [5] Considering these scenarios, a power-split transmission and a compound power-split electric continuously variable transmission (eCVT) have been introduced to improve the global efficiency of the system. Beside the input power split eCVT, there are more complex solutions with several transmission modes considering, in the system layout, at least two epicyclical gear trains and one or more locking system [12,13,14] These solutions can be classified as compound type power split and examples are Machines 2019, 7, 19; doi:10.3390/machines7010019 www.mdpi.com/journal/machines. A proper modelling and simulation tool is very important in the early design and analysis stage This is even more critical for the power-split HEVs due to the numerous available configurations/components and various control strategies [15,16,17]. An analytical expression of the efficiency of the compound transmission is shown, considering that the only dissipative device of the compound is the eCVT variator
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
