Piston Machine——gunaiyou

Combining an electric motor with one of the company’s digital positive displacement pumps in an excavator is the most efficient way to convert battery power into hydraulic work, according to new Danfoss research.

The Danish specialist in hydropower and electrification said the combination could reduce the amount of energy needed to operate during a typical working day, resulting in a battery size reduction of nearly 25%.aConstruction Europe spoke with Leif Brune, Head of Digital Movements at Danfoss Power Solutions, to discuss the implications of these findings.

Excavators account for 50% of all CO2 emissions from construction equipment, with excavators alone emitting 200 megatons per year. About 90% of emissions come from vehicles weighing 10 tons or more. Meanwhile, the efficiency of modern excavators is only 30 percent. About 70% of an engine’s energy is lost as heat in the hydraulic system.

At Danfoss, we believe that making excavators more efficient is the first step towards reducing the carbon footprint of the construction industry. The efficiency of the hydraulic system and the benefits of digital displacement control allow excavators to do the same workload with a smaller engine and less fuel, or do more work with the same size engine.

Readers can read the full research report. Thus, we developed a simulation model of a 16-ton crawler excavator and calculated the energy requirement for a typical eight-hour shift. It compares a basic electric motor equipped with a conventional swashplate pump to an electric excavator equipped with Dextreme Swap.

The results show that, depending on system complexity and duty cycle, a reduction in power consumption of up to 24.8% can be achieved. The advanced system requires a 314 kWh battery for eight hours of operation compared to the base 418 kWh battery.

How does this technology achieve this level of energy savings and how does it differ from conventional hydraulic pumps?

The digitally controlled displacement pump is the core component of our recently launched Danfoss Dextreme system solution.

Specifically designed for medium to large excavators, the Dextreme system can significantly increase the efficiency of an excavator system regardless of the power source, reducing energy consumption while maximizing productivity.

With Dextreme systems, our priority is to help our customers drastically reduce emissions, reduce energy consumption, increase productivity and reduce total cost of ownership.

The digitally controlled piston pump was the first and remains the only digitally controlled pump for off-highway hydraulic applications. It is controlled by a digital controller that activates each piston individually, providing fast and accurate control response to system requirements.

This provides unsurpassed efficiency at full and partial load. In addition, it can also be used as a multi-output pump, each output is independently controlled by a digital controller.

While I can’t speak to our discussions with specific OEMs, I can tell you that we are testing the technology with strategic customers in the UK and US. In addition, we are conducting a 12 month field trial of three 20 ton excavators with a major quarry operator in the UK.

Each machine is equipped with a Dextreme Swap system as well as data logging equipment that allows direct comparison with a standard excavator of the same model.

The first feedback we received was very positive. The company’s operators report that machines equipped with the Dextreme system are more responsive and productive.

In our study, we combined a digital piston pump with a Danfoss Editron motor and an inverter, resulting in a 25% energy saving. This is one way to be more efficient, but it is important to emphasize that our Dextreme system is suitable for any type of excavator: conventional, hybrid or electric.

With our approach to Dextreme system solutions, we can increase productivity while saving energy from 15% to 50%.

The simplest system configuration is what we call Dextreme Swap, which is available now and simply involves replacing the excavator’s hydraulic pump. With this system, we were able to reduce fuel consumption and CO2 emissions by 15% by reducing main pump losses.

Dextreme Flex is the next step after Swap, reducing fuel consumption and emissions by 30%. The system has a flexible flow outlet, which greatly reduces system losses.

Ultimately, we predict that our Dextreme Max system will cut fuel consumption and emissions by 50%. This level of savings can be achieved by recovering energy and controlling the hydraulic load directly from the pump, which reduces throttling losses in the main control valve.

All over the world, we are seeing regulations requiring low or zero emission vehicles in densely populated areas.

The Danfoss Dextreme system perfectly matches these trends. Today, it delivers scalable efficiency gains regardless of the machine’s power source. For diesel excavators, this is a direct path to electrification.

In the long term, the total cost of ownership of a Dextreme-equipped excavator will be lower than that of a standard diesel engine. In addition, we estimate that the Dextreme system can increase productivity by as much as 25%.

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