Accumulator Sizing for the Hybrid Hydraulic Electric Architecture (HHEA) Using Dynamic Programming

Jackson Wills, Perry Y. Li

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

The Hybrid Hydraulic Electric Architecture (HHEA) is an approach to electrifying and improving that does not require very large electric machines. The majority power is provided hydraulically via a set of common pressure rails while small electric machines are used to modulate that power to meet exact demand. Each common pressure rail has an accumulator, which keeps the pressure of each rail near constant as long as the volume in the accumulator does not change much. A main pump adds or removes fluid from each accumulator as needed to reduce volume changes in the accumulators. It is the operation of this main pump which is investigated here. In previous analysis it was assumed that the size of the accumulators was large enough to account for any difference in fluid volume without significantly changing the pressure. In this paper, the required accumulator sizes are studied using a dynamic programming approach. At each time step the inlet and outlet of the main pump could be connected to any of the common pressure rails. These decisions for the main pump were optimized to minimize the required accumulator size. Case studies are conducted using drive cycles from a 22- ton excavator, a 20-ton wheel loader and a 5-ton excavator. The machines could be operated with total accumulator sizes of less than 20, 10, and 5 liters respectively. Required accumulator size was found to vary with pump flow rate, the frequency at which the pump/motor was able to change operating conditions, the tolerance level of pressure deviation and the accumulator's polytropic index.

Original languageEnglish (US)
Title of host publicationProceedings of BATH/ASME 2022 Symposium on Fluid Power and Motion Control, FPMC 2022
PublisherAmerican Society of Mechanical Engineers
ISBN (Electronic)9780791886335
DOIs
StatePublished - 2022
EventBATH/ASME 2022 Symposium on Fluid Power and Motion Control, FPMC 2022 - Bath, United Kingdom
Duration: Sep 14 2022Sep 16 2022

Publication series

NameProceedings of BATH/ASME 2022 Symposium on Fluid Power and Motion Control, FPMC 2022

Conference

ConferenceBATH/ASME 2022 Symposium on Fluid Power and Motion Control, FPMC 2022
Country/TerritoryUnited Kingdom
CityBath
Period9/14/229/16/22

Bibliographical note

Funding Information:
This material is based upon work supported by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) under the Vehicle Technologies Office Award Number DE-EE0008384.

Publisher Copyright:
© 2022 by ASME.

Keywords

  • Accumulators
  • Component sizing
  • Dynamic Programming
  • Mobile Machines
  • Pressure Rails

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