Steady-State Characteristics Study of a Power Split Hydraulic Transmission

Feng Wang, Haoxiang Zhang, Bing Xu, Kim A. Stelson

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


The steady-state characteristics of a power split hydraulic transmission were carefully studied in this article. The hydraulic transmission is an alternative power split device for power split hydraulic hybrid drivetrain. It was built from a balanced vane pump, where an output shaft is added and coupled to its floating ring. The internal friction torques due to the relative motion between floating ring and vanes help to drive the output shaft. This improves the mechanical transfer efficiency from input to output shaft, making it more competitive than conventional hydrostatic transmission. The steady-state characteristics of the hydraulic transmission were investigated through both theoretical analysis and experimental studies. Mathematical models of the input and output shaft torques, and the outlet flow rate of the hydraulic transmission were developed. Studies show that the input and output shaft torques are not only dependent on outlet pressure, but also dependent on differential shaft speed. The outlet flow rate is proportional to the differential shaft speed. Finally, a hydro-mechanical transmission based on power split hydraulic transmission was introduced. The characteristics and system application of the hydro-mechanical transmission were given.

Original languageEnglish (US)
Article number9113430
Pages (from-to)78-89
Number of pages12
JournalIEEE/ASME Transactions on Mechatronics
Issue number1
StatePublished - Jun 10 2020

Bibliographical note

Funding Information:
Manuscript received January 16, 2020; revised April 10, 2020; accepted June 5, 2020. Date of publication June 10, 2020; date of current version February 16, 2021. This work was supported in part by the Natural Science Foundation of China under Grant 51875509 and Grant 91748210, in part by the NSFC-Shanxi Joint Fund under Grant U1910212, and in part by the NSFC-Zhejiang Joint Fund under Grant U1509204. Recommended by Technical Editor J. Yoon and Senior Editor X. Chen. (Corresponding author: Feng Wang.) Feng Wang, Haoxiang Zhang, and Bing Xu are with the State Key Laboratory of Fluid Power and Mechatronic Systems, School of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China (e-mail:;;

Publisher Copyright:
© 1996-2012 IEEE.


  • Balanced vane pump
  • hydro-mechanical transmission
  • power split hydraulic hybrid
  • power split hydraulic transmission


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