Advancing Hydraulics Research for Off-Highway Vehicles

By Eric Lanke
NFPA CEO

A recent NFPA Board meeting was held in Washington, DC, which gave me the opportunity to participate in several meetings at the U.S. Department of Energy (DOE), each focused on engaging that agency in the support of fluid power research.

One particularly noteworthy meeting was with the Vehicles Technology Office (VTO) of the DOE, which has been largely focused on energy savings in on-highway vehicles. We brought representatives from several organizations—NFPA, CCEFP, the Association of Equipment Manufacturers—and from several member companies in all three of those organizations—to try and make the case that energy savings in off-highway vehicles were just as, if not more, important, and that when looking for energy savings in that market, advances in the hydraulics systems on so many of those vehicles provide a unique opportunity. What is often not fully recognized by the VTO is that the off-road vehicle sector is fundamentally different than the on-road vehicle sector because most of the energy produced by off-road vehicles goes through hydraulic (fluid power) systems (e.g. excavators, mining equipment, farm equipment, etc.) and the off-road vehicles are one input (ICE) and multiple output (drivetrain and working functions) systems with different hardware architectures and duty cycles.

And we’re talking about significant amounts of energy—more than 400 trillion BTUs, according to some of the DOE’s own data. Couple that with NFPA’s own DOE-funded study, which showed that average fluid power system efficiency was in the neighborhood of 22 percent, and you begin to see the size of the opportunity we’re talking about.

Researchers from the CCEFP presented several potential areas of future study at our meeting, including:

1. Improvements in the efficiency of the fluid power systems (e.g. eliminating the losses that occur from valve throttling). This can be achieved through more efficient fluid power components (e.g. modular fluid power systems) and optimized system architecture (e.g. displacement based control rather than pressure based control).
2. Tighter integration of engine and fluid power distribution systems through optimized control systems and new system architectures such as hydraulic free piston engines and hybridization. Much like electric hybridization, hydraulic hybridization allows the engine to operate at its peak engine efficiency and the changes to loads is handled by storing/releasing energy in the fluid power system.
3. Vehicle level optimization through connected and automated vehicles. This could improve work site efficiency and the vehicle efficiency by reducing the losses by sub-optimal operations from inexperienced operators.
4. Increased engine efficiency. This refers to increasing the brake thermal efficiency of a combustion engine.  This opportunity overlaps significantly with the on-road vehicle sector and as such should not be a major focus of an off-road vehicle program.
5. To support the above technologies, systematic modeling and analysis tools are required. The on-road sector has mature modeling tools while the off-road sector doesn’t. This is limiting the development of new technologies for the off-road sector.

Our hope to engage the VTO in a roadmapping study—to convene a technology workshop of sorts, analyzing all the areas of opportunity, and mapping out the ones that are likely to bear the most fruit, so that future research dollars can be directed in the most effective manner. Keeping our industry members—and those of the CCEFP and AEM—engaged in this effort will be essential to its eventual success. If you’re interested in learning more, or participating in future discussions on this topic, please feel free to contact me.