Research Papers

Adjustable Linkage Pump: Efficiency Modeling and Experimental Validation

[+] Author and Article Information
Shawn Wilhelm

Department of Mechanical Engineering,
University of Minnesota,
111 Church St. SE,
Minneapolis, MN 55455

James Van de Ven

Assistant Professor
Department of Mechanical Engineering,
University of Minnesota,
111 Church St. SE,
Minneapolis, MN 55455

1Corresponding author.

Contributed by the Mechanisms and Robotics Committee of ASME for publication in the JOURNAL OF MECHANISMS AND ROBOTICS. Manuscript received February 3, 2014; final manuscript received July 30, 2014; published online December 4, 2014. Assoc. Editor: Philippe Wenger.

J. Mechanisms Robotics 7(3), 031013 (Aug 01, 2015) (8 pages) Paper No: JMR-14-1027; doi: 10.1115/1.4028293 History: Received February 03, 2014; Revised July 30, 2014; Online December 04, 2014

Variable displacement pumps are a key component to a variety of mobile and industrial hydraulic systems, yet the efficiency of existing pump architectures is poor at low displacement. As a solution to this issue, a new pump architecture is proposed that eliminates the planar hydrodynamic joints of a conventional architecture with rolling-element pin joints in an adjustable linkage. This new architecture uses an adjustable six-bar linkage that reaches true zero displacement and has the same top-dead-center (TDC) position regardless of displacement. In this work, the linkage kinematics and dynamics are discussed, an energy loss model is developed and used to drive design decisions of a first generation prototype, and experimental results are presented to validate the model. It is shown that this linkage-based, variable, positive displacement architecture shows promise as a highly efficient alternative to existing pump architectures across a wide range of displacements.

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Fig. 3

Free body diagram of the moving components of the linkage showing forces and centers of mass

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Fig. 2

Vector loop diagram of linkage for position analysis

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Fig. 1

Schematic of the adjustable linkage

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Fig. 4

Coulomb friction diagram showing pin joints relative to various links

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Fig. 5

Prototype variable displacement linkage pump used for low power experimental validation

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Fig. 11

Contour plot of model efficiency at constant pumping frequency and varying pressures of present design

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Fig. 12

Efficiency curve versus displacement for a pump with rolling element bearings at 21 MPa and 30 Hz

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Fig. 6

(a) Hydraulic circuit diagram displaying the experimental setup. (b) Image of the experimental setup showing the prototype.

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Fig. 9

Contributions of various loss terms as a function of displacement at 2.4 MPa and 3 Hz of present design

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Fig. 10

Contour plot of model efficiency at constant pressure and varying system frequencies of present design

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Fig. 7

Work output experimental data plotted against model at various frequencies and pressures

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Fig. 8

Work input experimental data plotted against model at various frequencies and pressures



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