A hydraulic hybrid excavator based on multi-chamber cylinders and secondary control – design and experimental validation

Keywords: multi-chamber cylinder, digital hydraulics, Secondary control


In this paper, a special type of multi-chamber cylinders along with secondary controlled hydraulic motors are key components in the design of a highly efficient hydraulic series hybrid system. The system is developed for and tested on a large excavator (30-ton class). The evaluated system supports potential and kinetic energy recovery and storage using hydraulic accumulators. Through proper sizing of components and sophisticated valve control, an energy-efficient flexible and robust hybrid system is achieved. The study describes how the demonstrator is tested in real truck loading cycles. A detailed energy analysis is also presented to explain the energy flow inside the hybrid system.


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Author Biographies

Kim Heybroek, Volvo Construction Equipment, Eskilstuna, Sweden

Kim Heybroek was born in Västervik, Sweden, in 1981. He received his MSc degree in Mechanical Engineering from Linköping University (LiU), Sweden in 2006. In 2008, he joined Volvo Construction Equipment in Eskilstuna where he is currently working. In 2017, he received his PhD degree at the Department of Fluid Power and Mechatronic Systems at LiU..

Mika Sahlman, Norrhydro OY, Tampere, Finland

Mika Sahlman was born in Pyhäselkä, Finland, in 1987. He received his MSc Degree in Mechanical Engineering from Tampere University of Technology (TUT), Finland in 2012. Later that year, he joined Norrhydro’s R&D team in Tampere where he is currently working as a Systems Engineer.


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How to Cite
Heybroek, K., & Sahlman, M. (2018). A hydraulic hybrid excavator based on multi-chamber cylinders and secondary control – design and experimental validation. International Journal of Fluid Power, 19(2), 91-105. https://doi.org/10.1080/14399776.2018.1447065
Original Article