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Research article2016Peer reviewed

Evaluation of a New Energy Recycling Hydraulic Lift Cylinder for Forwarders

Manner, Jussi; Lindroos, Ola; Arvidsson, Hans; Nordfjell, Tomas


In mechanized forestry, much of the work is conducted by use of cranes, and recovering potential energy is a possible method to reduce energy consumption when using cranes for lift work. The objective of this study was to evaluate the capacity of a new "Energy-efficient hydraulic lift cylinder" (EHLC), which has a secondary cylinder built into its piston rod, to store potential energy from lowering the boom in the form of pressurized hydraulic oil in an accumulator and using the stored energy in the next boom lift. The EHLC was mounted on a forwarder, and manipulated to enable its use also as a standard cylinder. We then compared the EHLC and a standard cylinder in terms of function and energy consumption during repetitive boom lifts and lowerings. With the tested settings the EHLC saved up to approximately 9.4% of the energy consumed during the first part of boom lifts and up to 3.2% of the total lift energy. With possible further adjustments, such as optimization of the accumulator size, enlargement of the assisting cylinder diameter, and enhancement of the accumulator pressurization, but most importantly reduction in internal leakage, the current EHLC could have commercial potential.


weight-balancing; fluid dynamics; fluid mechanics; timber loader; mobile hydraulic lift devices; Boyle's law; counterweight

Published in

Croatian Journal Of Forest Engineering
2016, Volume: 37, number: 2, pages: 219-231