Hydraulic Energy Recovery System Utilizing a Thermally Regenerative Hydraulic Accumulator Implemented to a Reach Truck

Henri Hänninen, Jyri Juhala, Jyrki Kajaste, Matti Pietola

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsProfessional


The implementation of an energy recovery system for retreiving otherways wasted energy is an effective method for reducing the overall energy consumption of a mobile machine. In a fork lift, there are two subsystems that can be effectively modified for recovering energy. These are the driveline and the lift/lower function of the mast. This study focuses on the latter by studying a recovery system whose main component is a hydraulic transformer consisting of a hydraulic motor, a variable displacement pump and an induction motor. Since the flow rate/pressure -ratio can be modified, the utilization of the hydraulic transformer enables downsizing of the accumulator volume. However, the decrease of the gas volume leads to an increase in the compression ratio of the accumulator, which in terms leads to higher gas temperatures after charging and consequently to higher thermal losses during holding phase. In order to reduce these losses, a thermally regenerative unit was implemented to the gas volume of an accumulator to reduce the temperature build up during charging. In this study, the effect of improving the thermal characteristics of the accumulator to the efficiency of the whole energy recovery system is investigated by means of measurements.
Original languageEnglish
Title of host publicationProceedings of the 10th International Conference on Fluid Power (IFK)
Subtitle of host publication8 - 10 March 2016, Dresden, Germany
PublisherTU Dresden
VolumeVolume 1
Publication statusPublished - 2016
MoE publication typeD3 Professional conference proceedings
EventInternational Fluid Power Conference - Dresden, Germany
Duration: 8 Mar 201610 Mar 2016
Conference number: 10

Publication series

NameInternational Fluid Power Conference


ConferenceInternational Fluid Power Conference


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