The new generation of Digital Displacement pumps

Wednesday, September 4, 2019

The future is digital

A new generation of Digital Displacement® pumps being developed in the UK promises a radical reduction in fuel consumption. Furthermore, a pathway to the electric off-highway machines of the future.

The off-road vehicles of tomorrow may consume less than half the energy used today. This is thanks to a technology being commercialized in the UK.

Last year a consortium led by Danish multi-national Danfoss and Edinburgh firm Artemis Intelligent Power secured £11 million from the Advanced Propulsion Center UK. This was to develop a new generation of ‘Digital Displacement®’ hydraulic pumps and motors to be used in off-road vehicles.

Less than 12 months later, Danfoss has acquired a majority stake in Artemis. Now it is forging ahead with plans to build a center of excellence and manufacturing facility in Edinburgh.

Danfoss is backing a British technology which has been 20 years in development. Now it is ready to transform the entire off-road market.

“There’s an urgent need to improve system efficiency for off-highway vehicles,” explains Dr Niall Caldwell, Managing Director at Artemis Intelligent Power.

“Hydraulics lie at the heart of most heavy machines, yet they rely on analogue pumps where – incredibly – more than half of the work done by the engine is wasted as heat in the hydraulic system.

“In contrast, Digital Displacement pumps can be embedded at the heart of any new machine to enable wholly new digitally-enabled architectures. This is offering improved control and a radical reduction in energy consumption.

“Where we are today is the result of many years of collaboration with Danfoss. The funding from the APC was the catalyst which unlocked their commitment to bring this product to market,” Caldwell says.

What is Digital Displacement®?

Hydraulic pumps lie at the heart of virtually every off-road vehicle in the world.  

They provide a controllable and compact way of transforming engine shaft power into the high force, linear motions required for common functions such as lifting and digging.  

Conventional hydraulic pumps are controlled by changing the stroke of the piston with an analogue ‘swash plate’ mechanism, first patented in 1893.

This mechanism has changed little since then and has a number of disadvantages – it is not easily controlled and there are many system energy losses, for example through idling, leakage and friction.

In fact, over half of the energy produced by an engine is wasted through losses in the hydraulic pump and system.  

Digital Displacement® technology is a fundamental innovation. It utilizes a radial piston machine which enables and disables cylinders in real time, using ultra-fast mechatronic valves controlled by an embedded computer.

These intelligent, digital controls mean a digitally-enabled machine is highly controllable and extremely efficient – individual cylinders are only called into action as and when required. The net result is:

  • dramatically lower energy losses;
  • dramatically faster response (typically ten times faster);
  • complete elimination of high-frequency noise

By embedding a digitally controlled pump at the heart of off-highway machines, completely new architectures can be achieved.  

OEM interest

Already Danfoss is in advanced discussions with several OEMS. Now they have commissioned the first state-of-the-art production line for the manufacture of Digital Displacement pumps.

“Digital Displacement is an incredible innovation which we believe will revolutionize the off-highway market,” says Eric Bretey, Director of Digital Displacement at Danfoss Scotland.

“Our initial focus is on the excavator market. Even when integrated as a simple ‘straight swap’ we can radically reduce energy loss in the pump and valve system and improve engine utilization,” Bretey says. 

In field trials, Danfoss compared a conventional diesel-powered excavator with an identical excavator equipped with a straight-swap Digital Displacement pump.

In a trial looking at the trenching function results included:

  • 15% improvement in trenching distance in an hour
  • 12% less fuel consumed per meter of trench
  • 17% better productivity than the current market leader

“The net result is reduced emissions and operating costs with short payback period,” Bretey says.

“However, if we look ahead to a new generation of fully integrated machines, the opportunities to rethink machine architectures means we will see even greater improvements in efficiency, cost and control.” 

Commenting on the project, Ian Constance, Chief Executive of the APC, said: 

"The challenge of lowering emissions is shared by the entire automotive industry and includes all areas of the sector. This project highlights the broad range of vehicle types that benefit from developments in low carbon innovation. We expect that this approach will help to create and safeguard jobs across the UK automotive sector. Furthermore, strengthen the UK's supply chain."

Electric enabler

Digital Displacement also has a key role as the off-road sector seeks to find cost-effective routes to electrification.

The tough duty cycles, harsh environment and high energy requirements of off-road machines mean that electrification can be a major challenge.

By embedding Digital Displacement pumps at the heart of new machines, OEMs can make electric excavators with improved productivity. Additionally, longer duty cycles or lower energy consumption.

“If we think about Digital Displacement technology applied to something like an electric excavator, we would expect to see significant improvements in run time for a given battery capacity or a reduction in the size of battery pack needed to perform a given duty cycle,” Bretey says.

“This would translate into a significant saving on the battery, and a large reduction in annual running cost.  

“Overall, we think Digital Displacement in a win-win for the off-highway sector. It’s a British-built invention which offers a radical reduction in emissions and lower cost in the short term. Furthermore, it maps out a pathway to full electrification enabled by higher system efficiency in the years ahead. 

“We think this is a very positive vision of the future,” Bretey concludes.

Digital Displacement® Technology

Digital Displacement® Technology

Digital Displacement® will deliver a new generation of digital hydraulic pumps and motors to deliver productivity and efficiency in customer machines that no competitor can match.