Power where it’s needed: engineering a more efficient solution for off-highway vehicle hydraulics

For off-highway vehicles, such as excavators, wheel loaders and forklift trucks, moving around the work site is only part of the challenge. Much of their energy is consumed in lifting, carrying or digging, for which the technology can often be comparatively old-fashioned and inefficient.

In 2018, the Advanced Propulsion Centre (APC) awarded a £10.9 million grant to the DDISPLACE project, which set out to address these challenges with a fundamental rethink on hydraulic system design. It was led by Edinburgh-based technology developer Artemis Intelligent Power, working in collaboration with Danish-American multinational Danfoss Power Solutions and hydraulic system specialist Robbie Fluid Engineering.

In place of a mechanically governed axial pump, the DDISPLACE concept uses a radial configuration, with the pistons actuated by computer-controlled valves. The consortium believed this could improve the efficiency of the system by up to 50 per cent, dramatically reducing emissions and energy consumption.

Furthermore, it could play a key role in enabling electrification of heavy commercial vehicles. Danfoss has also developed an electric powertrain as part of a second APC-backed project, and the company estimates that the two technologies combined could reduce the lifetime CO2 emissions of the global excavator fleet by 80 Megatonnes (Mt) by 2030. That’s roughly the same as the entire annual CO2 emissions of Denmark and Scotland combined.

The technology behind the DDISPLACE project was originally developed by Artemis Intelligent Power. Shortly after the beginning of the project, Danfoss began its acquisition of the Edinburgh company, which is now a wholly owned subsidiary.

The project focused on productionising the technology, as Alasdair Robertson, Director of Product Portfolio and Marketing for Digital Displacement at Danfoss Power Solutions, explains: “At the beginning of the project, we were producing very small numbers of Digital Displacement pumps as technology demonstrators. These were hand built by individual technicians who would see the pump the whole way through the production process. That methodology works well for prototypes, but it’s simply not feasible for mass production. The level of detail and the supply chain quality required to make that step up has been quite eye opening from a technology developer’s point of view.”

The APC funding for the DDISPLACE project alongside the acquisition by Danfoss, provided the team with resources to upscale the production and provide a proven route for taking this technology to market.

“Much of the hydraulics industry relies on iterative development, with a lot of expertise surrounding traditional methods and a huge supplier base devoted to that technology,” comments Robertson.

“But with Digital Displacement we had to create that from scratch. It’s a step change in the technology, and the APC funding has allowed us to work through the risks associated with taking that leap.”