The novel Common Pressure Rail Hybrid system applied to excavators is the innovation that led to the award.
The new technology results in radical improvements in energy-efficiency and resulted in it receiving the Volvo Technology Award for 2021. The Volvo CE team from Sweden and South Korea has worked closely with Finnish company Norrhydro in the research project, leveraging an idea initially born out of academic collaborations. Today, the innovation has matured into a real-world solution with ongoing customer trials in the field and it is expected to accelerate the introduction of e-mobility across Volvo CE’s larger excavator platform. The company anticipates the new technology to be available in the excavator market in a near future.
This innovation enables Volvo CE to offer its customers a unique electro-hydraulic solution, pushing fuel efficiency to new levels. The innovation enables new ways to reduce energy losses in hydraulics. In the new system architecture, all the machine's work functions are connected to a hydraulic energy storage via a common pressure rail, comprised by two or more pressure lines. The energy storage, which consists of hydraulic accumulators, enables energy-efficient recovery of kinetic energy and peak power supply. For cylinder-driven functions, so-called “smart actuators” are used to achieve energy-efficient conversion from hydraulic power to a variable force and speed. The system also allows energy recovery and performance increase of the machine's rotating loads, such as the swing function through the introduction of variable hydraulic machines. Thanks to greatly reduced energy losses and the power contribution from hydraulic accumulators, a smaller power source can be used and the need for cooling is reduced. With a higher available power, cycle times can be shortened, for example when loading a truck, which contributes to both efficiency increases and cost benefits for the customer. Source