Characterization of the fluid deaeration device for a hydraulic hybrid vehicle system

Jason Zachary Moore, Rodolfo J. Somoza, Albert J. Shih, Zoran S. Filipi, Andrew J. Moskalik, Neil M. Johnson

Research output: Contribution to conferencePaperpeer-review

2 Scopus citations


The attractiveness of the hydraulic hybrid concept stems from the high power density and efficiency of the pump/motors and the accumulator. This is particularly advantageous in applications to heavy vehicles, as high mass translates into high rates of energy flows through the system. Using dry case hydraulic pumps further improves the energy conversion in the system, as they have 1-4% better efficiency than traditional wet-case pumps. However, evacuation of fluid from the case introduces air bubbles and it becomes imperative to address the deaeration problems. This research develops a bubble elimination efficiency testing apparatus (BEETA) to establish quantitative results characterizing bubble removal from hydraulic fluid in a cyclone deaeration device. The BEETA system mixes the oil and air according to predetermined ratio, passes the mixture through a cyclone deaeration device, and then measures the concentration of air in the exiting fluid. Test results indicate the ability of the cyclone deaeration device to remove large bubbles with near 100% efficiency, while elimination of small (less than 1 mm diameter) bubbles proved to be a challenge. The explanation is provided through application of Stokes Law that shows a strong relationship between bubble size and bubble rise velocity. The theoretical analysis provides clear guidance regarding pathways towards improving the effectiveness of removing small bubbles.

Original languageEnglish (US)
StatePublished - Dec 1 2008
Event2008 World Congress - Detroit, MI, United States
Duration: Apr 14 2008Apr 17 2008


Other2008 World Congress
Country/TerritoryUnited States
CityDetroit, MI

All Science Journal Classification (ASJC) codes

  • Automotive Engineering
  • Safety, Risk, Reliability and Quality
  • Pollution
  • Industrial and Manufacturing Engineering


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