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Are hydrogen engines the answer?

March 16, 2023
Along with being used in fuel cells, hydrogen can also fuel internal combustion engines. And while not always being the most efficient, fleets may find they are the most proficient for now.

With all the recent changes to the industry, the questions transportation leaders are now asking have gone from “where do I begin?” and “where do I want to go?” to “how the heck am I going to get there?”

Obviously, there are many factors that go into answering that question, but if we’re focusing on efficiency (and that is NACFE’s job), we should start with the powertrain and fuel source.

And that brings us to innovative internal combustion engines (ICE) modified and built to operate on hydrogen fuel. At first glance, using an ICE—whether filled with gasoline or diesel—sounds like a pretty good option since we already have many engine manufacturers successfully building these in highly efficient facilities, and with a multitude of skilled engineers

They can generate NOx emissions, though not at the level of diesel. According to Cummins, "converting medium and heavy-duty trucks to clean hydrogen would eliminate about a quarter of all greenhouse gas emissions from the [U.S.] transportation sector."

Why not stay the course and modify for hydrogen? The transmission manufacturers were extremely successful in their evolution from the manual transmission to the automated transmission. But will the same success play out with hydrogen internal combustion engines (H2-ICE)?

I was reading an article in Hydrogen Insight by Rachel Parkes, "Why the world needs hydrogen combustion engines – even though they’re so inefficient," that stopped me in my tracks.

Inefficient? With all the complications associated with trucking, the last thing a manager wants to worry about is inefficiency. Her headline begs for more reading and through her interview with Jim Nebergall, head of Cummins’ H2-ICE program, it all begins to make sense.

One major reason is because it is still internal combustion the fleets would deal with, and not a brand new electric powertrain. Second, from a financial perspective, a battery electric truck with an extended range of 500 miles would cost 120% more than a diesel truck, while an H2-ICE version would only be 50% more.

Nebergall added that fuel cells run very hot, and therefore require more energy toward cooling. These cells will also lose efficiency over time.

With large initial investments for the battery electric vehicle (BEV) and hydrogen fuel cell vehicle facility infrastructure, technician acceptance and training, refueling logistics and a host of other issues, some managers are willing to accept the inefficiency versus outlaying funds for the initial purchase price of these new vehicles until a time when infrastructure has developed, and vehicle costs are at an acceptable point.

This all makes sense, but which H2-ICE platform do I use in my modified diesel engine: port fuel injection, direct injection, spark ignition, or compression ignition?

Comparing the newly released information on the Cummins 15L hydrogen engine with their successful X15N natural gas engine, we can see much similarity in construction using spark ignition, along with direction injection of fuel. This makes complete business sense with building upon a proven technology that is already in place.

The exciting part of the promotion of zero-emission vehicles is that it is a global effort. Take India for example. In an article in Express Mobility by Mulgund, Srihari, "Hydrogen ICE: A green engine to drive into the future," the author writes, “On January 4, the Union Cabinet approved the National Green Hydrogen Mission to promote the hydrogen ecosystem.” With this venture the Union Cabinet, is looking to not only reduce carbon emissions, but also to gain energy independence. From their standpoint it seems that utilizing H2-ICE is the quickest way to achieve their goals through minimum changes to the engines.

The trucking industry is very diversified in many ways, from vehicles, products being hauled, geographic areas, seasons and other things that make up the entire industry. But other factors must be considered.
And that leads to several new questions.

Is the loading dock inside or outside? Many locations ban hydrogen vehicles indoors because of the potential for an explosion. What about breakdowns in unknown locations where qualified service is required? Should I buy or lease with service and fuel? Will my shop be capable of safely working on these vehicles?

We are on the road of progress that doesn’t necessarily have a road map. But still, we will continue to haul goods because that’s what we do best.