System for hydraulic
energy recovery
INTRODUCTION
Most construction machines have hydraulic systems for
lifting and lowering loads. When lowering the load a
large flow goes directly to the tank and a big power loss
appears in form of heat. It is interesting to investigate if it
is possible to recover this power loss to increase the
system efficency. Most vehicles can be equiped with a
hybrid system where a separate power source is used
together with the combustion engine. There are different
types of hybrid systems, namely one where it is used in
series with the driveline and one where it is used
parallell to the driveline. In this project a parallell system
is analysed.
CONCLUSION
To be able to recover the loss of power one needs to
have a place to store the energy. This is achieved
with an accumulator working together with a
hydraulic transformer. The transformer is used to
charge and discharge the accumulator. Thanks to the
transformer, high pressure and low flow can be
transformed to low pressure and high flow and vice
versa. This is used in the functions Stop and Go,
Power boost and Torque leveling.
Team members
Andreas Johansson - Team leader
Andreas Klintemyr - Documentation
Robin Bergström - Quality and hardware
Daniel Kvaldén - Test manager
Michael Eklund - Simulation
Martin Eriksson - Control system
All team members study the fifth year in mechanical
engineering.
Supervisors
Kim Heybroek - VOLVO CE
Karl Pettersson - PhD student
Hydraulic Transformer Group
Division of Fluid and Mechatronic Systems
Project course TMPM01
Linköping University, Autumn 2010