Energy management of low-pressure systems utilizing pump-unloading valve and accumulator

Patrick M. Stump, Nathan Keller, Andrea Vacca

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


In the context of improving energy efficiency and fuel consumption of mobile hydraulic equipment, it is important to analyze all the sources of power loss occurring within the hydraulic systems. While plenty of analyses have been performed on the working implements and the main transmission systems, very little attention has been paid to low-pressure (LP) systems until recently. LP systems are required on closed-circuit hydraulic systems to replenish losses, provide cooling flow, and maintain a pilot pressure necessary to operate hydraulic control valves and variable displacement units. It is shown that these circuits, which are often thought to have minimal impact on power consumption, actually cause significant, continuous power loss. A new method of power savings in these circuits is investigated through management of charge pump flow by application of an accumulator-sense pump-unloading (ASPU) valve. This work further proposes the combination of a split LP architecture with an ASPU valve. Three systems are simulated using Simcenter Amesim® and MATLAB/Simulink®. Using realistic duty cycles and unit loss models on a circuit for mobile off-road hydraulic equipment, it is shown that a standard LP system can consume about 5 kW of power. Power savings of up to 65% over a standard LP system are demonstrated by the proposed architecture.

Original languageEnglish
Article number4423
Issue number23
StatePublished - 21 Nov 2019
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2019 by the authors


The authors graciously acknowledge Xiaofan Guo for his assistance in developing the analytical equations. The authors also thank Maha Fluid Power Research Center and Purdue University for graduate assistantship funding which made this research possible.

FundersFunder number
Maha Fluid Power Research Center
Purdue University


    • Accumulator
    • Charge pump
    • Energy efficiency
    • Fluid power
    • Hydraulics
    • Low pressure system
    • Power loss
    • Unloading valve


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