Understanding overall efficiency of hydrostatic pumps and motors

Authors

  • Gustavo Koury Costa Department of Mechanics, Federal Institute of Science and Technology of the State of Pernambuco, Recife, Brazil
  • Nariman Sepehri Department of Mechanical Engineering, University of Manitoba, Winnipeg, MB, Canada

DOI:

https://doi.org/10.1080/14399776.2018.1476306

Keywords:

overall efficiency, hydraulic motors, Hydraulic pumps

Abstract

Pump and motor efficiency is a complex subject, to such an extent that most of the available models describing efficiency today rely on experimental data. In spite of that, mathematical models relating efficiency to pressure and angular speed have been proposed throughout the years. In all these models, volumetric and mechanical efficiencies are separately built from flow and torque losses relations. The overall efficiency model is then obtained by multiplying the volumetric and the mechanical efficiency equations. In this paper, we show that the overall efficiency equations must be developed from an energy balance and show that the simple multiplication of mechanical and volumetric efficiencies can potentially lead to inaccurate results. We then obtain a generalised equation relating the overall efficiency to pressure and angular speed for both pumps and motors and show how the resulting model can be fitted to actual experimental data.

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Author Biographies

Gustavo Koury Costa, Department of Mechanics, Federal Institute of Science and Technology of the State of Pernambuco, Recife, Brazil

Gustavo Koury Costa works at the Federal Institute of Education, Science and Technology in Recife-PE, Brazil. He received his MSc and DSc degrees from the Federal University of Pernambuco, Brazil. He did his Post- Doctorate in the University of Manitoba, Canada, having become adjunct professor for the Faculty of Mechanical Engineering.

Nariman Sepehri, Department of Mechanical Engineering, University of Manitoba, Winnipeg, MB, Canada

Nariman Sepehri is a professor with the Department of Mechanical Engineering, at the University of Manitoba, Canada. He received MSc and PhD degrees from the University of British Columbia, Canada. His research and development activities are primarily centred in all fluid power-related aspects of systems, manipulation, diagnosis, and control.

References

Akers, A., Gassman, M., and Smith, R., 2006. Hydraulic

power system analysis. USA: CRC Press.

Blackburn, J.F., Reethof, G., and Shearer, J.L., 1960. Fluid

power control. USA: Technology press of M.I.T. and

John Wiley & Sons.

Costa, G.K. and Sepehri, N., 2015. Hydrostatic transmissions

and actuators – operation, modelling and applications.

UK: John Wiley & Sons.

Doddannavar, A. and Barnard, A., 2005. Practical hydraulic

systems: operation and troubleshooting for engineers and

technicians. Elsevier, US.

Dorey, R.E., 1988. Modelling of losses in pumps and

motors. First Bath International fluid power workshop,

September. UK: University of Bath, 71–97.

Esposito, A., 1980. Fluid power with applications. 4th ed.

USA: Prentice Hall.

Fitzgibbon, A.W., Pilu, M., and Fisher, R.B., 1996. Direct

least squares fitting of ellipses. IEEE transactions on

pattern analysis and machine intelligence, 21 (5), 476–

doi:10.1109/34.765658

Halir, R. and Flusser, J., 1998. Numerically stable direct

least squares fitting of ellipses. Proceedings of the 6th

International conference in Central Europe on computer

graphics and visualization, Pizen, Czech Republic:

WSCG, pp 125–132.

Hall, S.J. and Steward, B.L., 2014. Comparison of steady

state flow loss models for axial piston pumps. In:

International Fluid Power Exposition (IFPE), Paper 4.1,

Las Vegas, US.

Ivantysyn, J. and Ivantysynova, M., 2000. Hydrostatic

pumps and motors, principals, designs, performance,

modeling, analysis, control and testing. New Delhi:

Academia Books International.

Jeong, H., 2007. A novel performance model given by the

physical dimensions of hydraulic axial piston motors:

model derivation. Journal of Mechanical Science and

Technology, 21 (1), 83–97. doi:10.1007/BF03161714

Jung, D.S., Kim, H.E., Jeong, H.S., Kang, B.S, Lee, Y.B., Kim, J.

K., Kang, E.S., 2005. Experimental study on the performance

estimation efficiency model of a hydraulic axial

piston motors. Proceedings of the 6th JFPS International

symposium on fluid power, TSUKUBB, 284–290. 2A3–1,

Japan Fluid Power System Society - JFPS.

Kluger, M.A., Fussner, D.R., and Roethler, B., 1996. A

performance comparison of various automatic transmission

pumping systems. SAE International congress &

exposition, Detroit, US, 33–40. doi:10.1016/S0940-2993

(96)80089-3

KohmäScher, T., et al., 2007. Improved loss modeling of

hydrostatic units: requirement for precise simulation of

mobile working machine drivelines. In: ASME 2007

International mechanical engineering congress and exposition

volume 4: design, analysis, control and diagnosis of

fluid power systems, ASME, Seattle, WA.

Manring, N.D., 2005a. Hydraulic control systems. US: John

Wiley & Sons.

Manring, N.D., 2005b. Measuring pump efficiency: uncertainty

considerations. Journal Energy Resources

Technological, 127 (4), 280–284. doi:10.1115/1.1926311

Manring, N.D., 2016. Mapping the efficiency for a hydrostatic

transmission. Journal of Dynamic Systems,

Measurement, and Control, 138, 0310041–0310048.

doi:10.1115/1.4032289

McCandlish, D. and Dorey, R.E., 1984. The mathematical

modeling of hydrostatic pumps and motors. Proceedings

of the Institution of Mechanical Engineers, 198B (10),

–174. doi:10.1243/PIME_PROC_1984_198_062_02

Merritt, H.E., 1967. Hydraulic control systems. US: John

Wiley & Sons.

Sauer-Danfoss, 2010. Series 40 axial piston pumps technical

information. US. October. 520L0635 Rev EJ - Sauer-

Danfoss, US.

Stringer, J., 1976. Hydraulic system analysis: an introduction.

US: John Wiley & Sons.

Szpak, Z.L., Chojnacki, W., and Van Den Hengel, A., 2012.

Guaranteed ellipse fitting with the Sampson distance.

Proceedings of the 12th European conference on computer

vision, Part V, 7–13 October. Florence, Italy.

Tessmann, R.K., 1979. A leakage path model for a hydraulic

pump. The B.F.P.R Journal, 12 (1), 5–9.

Watton, J., 2009. Fundamentals of fluid power control.

Cambridge University Press, UK.

Wilson, W.E., 1946. Rotary-pump theory. ASME

Transactions, 68, 371–384.

Wilson, W.E., 1949. Performance criteria for positive-displacement

pumps and fluid motors. ASME Transactions,

(2), 115–120.

Zarotti, G.L. and Nervegna, N., 1981. Pump efficiencies

approximation and modelling. 6th International fluid

power symposium, Paper C4, Cambridge, UK. 145–164.

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Published

2018-08-01

How to Cite

Costa, G. K., & Sepehri, N. (2018). Understanding overall efficiency of hydrostatic pumps and motors. International Journal of Fluid Power, 19(2), 106–116. https://doi.org/10.1080/14399776.2018.1476306

Issue

2018: Vol 19 Iss 2

Section

Original Article

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