Cummins New Hydrogen Combustion Engine Platform Takes On Diesels

Cummins New Hydrogen Combustion Engine Platform Takes On Diesels

Cummins New Hydrogen Combustion Engine Platform Takes On Diesels



Cummins Engine

With the onslaught of electrification and battery-electric vehicles (BEVs) in the works, many have predicted the end of internal combustion engines. But some manufacturers are taking a different approach to reduce the greenhouse gas effect by using hydrogen as an internal combustion engine fuel.

Cummins announced two new hydrogen variants based on a new fully fuel-agnostic platform. Above the head gasket is where components change, depending on the fuel type. Below the head gasket will be a short-block common across the variants.

In Japan, for example, a consortium of OEMs including Mazda, Yamaha, Toyota, and Kawasaki has banded together to develop hydrogen solutions for ICE. Meanwhile, some companies, including Cummins, have jumped into the hydrogen mix in North America. Cummins recently announced that it is testing two hydrogen-powered variants for medium- and heavy-duty markets. 

Cummins believes that the transportation industry should develop multiple solutions to meet the demands of on- and off-highway uses due to the wide variation in applications and operating environments. BEVs are thought to be impractical for many of these heavy-duty applications. This is where hydrogen may be the more practical choice for OEMs in the future. 

The transportation industry is adding the most carbon emissions to the atmosphere. Cummins believes it can scale up hydrogen combustion engines by decade’s end.

Zero Carbon

Last July, Cummins announced that it was dipping a toe in the water and testing hydrogen internal combustion (ICE) technology. Since then, the company has achieved power and torque targets (over 810 lb-ft torque and 290 horsepower from the medium-duty engine with aims of 500 horsepower and more than 1,000 lb-ft of torque for newer prototypes). Remember that Cummins has a significant global manufacturing footprint, so the company can quickly scale production once the bugs are worked out. 


The engine platform will be a “zero-carbon fueled solution for multiple markets,” according to Cummins. It intends to produce hydrogen internal combustion engines in both 15.0-liter and 6.7-liter displacements, believing that these engines are the market’s sweet spot and will allow it to take action and reduce greenhouse gas emissions in this decade.

Hydrogen-combustion engines can be implemented with a lower initial cost than a hydrogen fuel cell or BEV, with only minor modifications to today’s vehicles. OEMs entering the hydrogen-combustion market may also benefit from the early adoption and scale of hydrogen-powered vehicles, as features such as extended vehicle range, fast fueling, powertrain commonality, and user familiarity attract customers. 

“Heavy-duty trucking is critical to the global economy and is one of the hard-to-abate sectors of the economy.” — Daryl Wilson, Executive Director of the Hydrogen Council. 


“We are encouraged by progress at Cummins in the development of hydrogen-fueled internal combustion engines and look forward to continued advancements that can help us reach cost-effective decarbonization of economies worldwide,” says Hydrogen Council’s Executive Director Daryl Wilson

Cummins is betting on hydrogen combustion in the short term because medium- and heavy-duty applications are much more likely to switch to this fuel when it is available. In the coming decade, buses and long-haul trucks running on hydrogen will become a common sight, according to Cummins. If hydrogen can grow in this market and be a fuel of choice for heavy-duty customers, Cummins believes it will be complementary to battery-electric buses and trucks that are economically and operationally viable for certain applications. 

Other applications such as construction equipment, agricultural machinery, and even ships may join the hydrogen engine mission soon. These are most likely applications that are hard to electrify due to their usage demands, and already have variants powered by various gaseous fuels.  


The black valve cover and “X15N” marking indicate this X15 engine is configured for natural gas operation.

RAM Tough?

A hydrogen internal combustion engine will both physically fit in today’s trucks and work with current transmissions. They will also integrate seamlessly into the industry’s existing service networks and practices. For fans of RAM trucks, the 6.7L Cummins hydrogen engine would fit neatly into one of their heavy-duty pickup models. And it appears that Stellantis is bullish on hydrogen, too, as it has alluded to running this fuel as soon as 2024. 


Cummins plans to use its new fuel-agnostic engine platform to help develop hydrogen combustion engines moving forward. The 6.7-liter and 15-liter will have optimized cylinder heads with flexible overhead cam systems that can be swapped, depending on the fuel used (i.e., natural gas, diesel, or hydrogen). The hydrogen-specific heads will offer improved cooling and reduced friction to achieve a more efficient and higher power density from the platform. The changes between fuels will, in theory, only change above the head gasket.

According to Srikanth Padmanabhan, president of Engine Business for Cummins, there were too many limitations and other compromises associated with converting a diesel or natural gas engine over to hydrogen, so a new platform was necessary. 

“[We] have designed an advanced optimized combustion chamber for fuel mixing, charge motion, and turbulence generation that we believe is critical for fast hydrogen combustion to maximize power density and efficiency,” Padmanabhan explains. “It’s also important to note that this combustion system will synergize with our next-generation high power density, high-efficiency natural gas engines.”

CNG Experience

With decades of experience with natural gas-powered engines, Padmanabhan adds that Cummins is primed for the challenge of hydrogen ICE as the industry shifts to zero-carbon.  

Cummins is currently testing prototype hydrogen engines with the goal of 500 horsepower and 1,000 lb-ft of torque for the heavy-duty segment.

“Launching the hydrogen engine also benefits other paths to reach a zero-carbon future, such as hydrogen fuel cells,” he says. “By creating a viable use case and demand for hydrogen in the near term, we can accelerate hydrogen infrastructure build-out and increase scale production of vehicle storage tanks. Both advances are necessary for the widespread adoption of fuel-cell powertrains.”

Jim Nebergall, General Manager, Hydrogen Engines at Cummins, says their customers have positively responded to this new initiative because the hydrogen ICE platform is based on familiar componentry. “These engines look like engines, sound like engines, and fit where engines normally fit.”

In May, the company debuted its 15-liter hydrogen engine at ACT Expo in Long Beach, California. It will be built on its fuel-agnostic platform, where the engines use similar components below the head gasket. Above the head gasket, each has different features for the different fuel types. The 15-liter version is expected to be in full production in 2027. The 6.7-Liter engine could be in production as early as 2023-’24.

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