Hydrogen on ICE, That’s Nice!

Hydrogen use in Tier-3 NextFuel™ engine highlights Wabtec as a leader in alternative fuels

‘First fire’ on hydrogen

Remember this date: May 15, 2024.

On that Wednesday afternoon, in a test facility at Southwest Research Institute’s (SwRI) main campus in San Antonio, Texas, Wabtec research engineers achieved ‘first fire’ (i.e., combustion) in a dual-fuel, hydrogen-diesel engine.

They introduced hydrogen into a full-scale, 4,500 horsepower Wabtec Evolution Series Tier 3 engine, which is a staple of railroad locomotive fleets around the world (several thousand locomotives with Evolution Series engines are in service today), and it worked … within the parameters expected.

Just to be clear: A hydrogen internal combustion engine (H₂ ICE) is still years off. But attaining ‘first fire’ is an important early step on that journey and getting to this point highlights Wabtec’s innovative spirit – and practical business approach – as it is a leader in an already fuel-efficient rail industry towards a net-zero future.

A ‘diverse’ approach: Dual-fuel engines

Hydrogen as a (non-fossil) fuel source has captured the imagination of freight rail, and of business at large, because it burns carbon-free. While the element itself is widely abundant in the universe, large supplies of “green,” cost-competitive hydrogen and the required infrastructure to distribute it are not. It is also the lightest element and extremely flammable, posing unique design challenges for locomotive engine designers.

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Yet for all of hydrogen’s many unique characteristics, Wabtec thinks the answer to turning it into a productive, zero-carbon emissions fuel for existing freight locomotive fleets lies in its commonalities with other power sources. Put another way, H₂ is a gas, and Wabtec knows how to burn gas in a high-performance internal combustion engine. Better yet, Wabtec knows how to burn natural gas in a dual-fuel engine that can seamlessly switch back to diesel as needed, something it is already doing in a commercial environment with its NextFuel™ locomotive for Florida East Coast Railway.

This distinction is important, because, once again, Wabtec is innovating efficiently, showing the industry it doesn’t have to re-invent the wheel to accommodate an emerging alternative fuel source. Instead, Wabtec is looking to make that alternative fuel, in this case hydrogen, work effectively within an existing engine platform purpose-built for (fuel) flexibility, enabling customers to benefit from new fuels as they become viable.

“The temptation to treat hydrogen, and the development of a hydrogen internal combustion engine, as a challenge requiring a radically new approach is powerful, but one we have successfully resisted through good planning and even better execution,” says Jim Gamble, Vice President, Engine and Power Solutions, Wabtec. “With our dual-fuel, NextFuel™ engines, Wabtec has modified our popular existing diesel engines to a) accommodate alternative fuels and b) switch seamlessly – and automatically – back to diesel as needed.”

This approach to innovation ensures rail-customer needs are built into emission-reducing technologies, especially their concerns about alternative fuel infrastructure and availability. For example, Wabtec successes of using alternative fuels in existing engines with its  NextFuel kits, be they LNG, biodiesel, or renewable diesel, enable carriers to switch between fuel types as the situation on the ground demands. That means that when an alternative fuel isn’t available in a given territory, or the infrastructure to deliver it isn’t ready at any given time, diesel can, and will, still get the job done – automatically, and all while using one, high-performing engine.

This is particularly important in the evolution of hydrogen-burning engines, where the buildout of a hydrogen-fuel infrastructure is in just as early a stage as the development of the H₂ ICE itself.

“We’ve learned from experience that it isn’t a good idea to innovate too far in front of what our rail customers can practically use,” adds Gamble. “By making advances in the use of hydrogen as a fuel in our working NextFuel platform, we’re ensuring the progress we do make happens within a delivery model the industry has already embraced and can easily accommodate.”

Bringing hydrogen closer to the customer

Wabtec has been making waves in the field of hydrogen-powered trains ever since announcing large-scale research deals with the Department of Energy’s Oak Ridge and Argonne National Laboratories. This work has focused on testing a variety of alternative fuels, including hydrogen, on a Wabtec single-cylinder dual-fuel locomotive engine installation at the Oak Ridge Lab.

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In parallel to establishing this important test bed, Wabtec senior leadership challenged its Engine and Power Solutions team to bring hydrogen research “closer to the customer” and their daily experience, making it less theoretical and something they could touch and feel.

The result was a new partnership with SwRI and a hydrogen regimen conducted on a NextFuel Evolution Series Tier 3 engine similar to the one in use at Florida East Coast Railway, with modifications for hydrogen fuel use. This dual-fuel engine was a “natural” for initial hydrogen testing, because it, too, burned a gas, i.e., natural gas, along with diesel.

Yet, commonalities aside, hydrogen is not natural gas. For starters, hydrogen is a lot lighter. In fact, as the lightest element on the periodic table, it wants to rise three stories per second. Just how that would impact the design of the engine’s fuel-delivery system would need to be seen. Additionally, hydrogen’s ignition energy is very low – much lower than natural gas – and it’s flammability range is extremely wide.

Combustion matters

That said, Wabtec has begun this testing from a position of strength. It had already modified its Evolution Series Tier 3 engine to burn natural gas, making changes to both its engine and locomotive hardware.

Wabtec’s goal is to piggyback on, and in some cases leapfrog over, these advances, making the tweaks and bigger changes necessary to corral, then optimize, hydrogen as a sustainable fuel source. For example, is the current piping and engine architecture sufficient to feed hydrogen, which is 6x lighter than natural gas, from the tender to the combustion chamber? Would it be better to inject hydrogen directly into the combustion chamber (direct injection) vs. into the intake manifold (port injection)?

These and hundreds of other questions and variables are, and will continue to be, the subject of extensive testing on both the single cylinder installation at Oak Ridge National Laboratory and the Tier 3 NextFuel engine at SwRI.

“One heck of a head start”

“We’re at an exciting inflection point in our thinking about hydrogen where we can move from the theoretical to actually testing our assumptions on real, high-performance engines our customers know well and rely on,” concludes Gamble. “By listening to our customers and focusing on ways to deliver emissions-saving technologies rapidly, incrementally, and in as seamless a way as possible, Wabtec has enabled the freight rail industry to make a significant impact on its carbon-reduction goals today.”