Energy recovery. A Volvo Construction Equipment team unveiled a ground-breaking new system architecture for excavators last year. Aimed at reducing energy losses in hydraulics, the new system architecture was being tested in the field. The machine’s work functions are connected to a hydraulic energy storage via a common pressure rail, comprised of two or more pressure lines. The energy storage (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, noted Volvo’s team. The system can recover energy and increase performance of the machine’s rotating loads, such as the swing function through the introduction of variable hydraulic machines. With more power available, cycle times can be reduced (for example, when loading a truck), which contributes to both efficiency increases and cost benefits for users.
Improved duty cycle. When Danfoss engineers analyzed the energy flow in excavators, they discovered that 70% of the useful energy made by the engine disappeared as waste heat. Danfoss has developed its Digital Displacement (DDP) technology to help address this by simply swapping out the conventional pump. Replacing a standard pump with a single- or multi-outlet 96cc Digital Displacement Pump can significantly increase the productivity of hydraulic machinery, enhance control and reduce energy consumption, they noted.
According to Danfoss, DDP technology can cut fuel consumption in excavators by 25-30%. The technology uses a radial design, which enables pistons in real time, using ultra-fast mechatronic valves controlled by a dedicated controller.
“It is digital hydraulics for the digital age,” said Niall Caldwell, director, Danfoss Digital Displacement. “It is going to be a very creative phase for the whole industry as we learn how to apply the technology to solve a myriad of problems that customers have.”
Reference: Rehana Begg, Power&Motion. powermotiontech.com