Cummins unveiled a 15L hydrogen engine at ACT Expo in Long Beach, California, May 9. Built on Cummins’ new fuel-agnostic platform announced earlier this year, it’s expected to go into full production in 2027. Cummins also plans to release a 6.7L hydrogen engine.

It was part of a display demonstrating Cummins’ Destination Zero strategy for key on-highway markets, which aims to reach net-zero emissions by 2050.

In addition to the new X15H, Cummins showed off its X15N natural-gas engine it announced last fall, the new B6.7 Propane engine, Cummins Clean Fuel Technologies Fuel Systems, its fuel-cell electric demonstrator truck, a terminal tractor featuring the PowerDrive 8000 battery-electric system, and a Cummins-powered Blue Bird battery- electric school bus.

Cummins Hydrogen Engines

The X15H is built on a new fuel-agnostic engine platform, where below the head gasket each fuel type’s engine has largely similar components, and above the head gasket, each has different components for different fuel types.

Cummins announced the testing of hydrogen internal combustion technology in July 2021. At ACT Expo, officials said the company has had impressive early results, already achieving production power and torque targets (over 810 ft-lbs torque and 290 hp from the medium-duty engine). Additional testing on more advanced prototypes will begin soon.

The engine will be a zero-carbon fueled solution for multiple markets. Cummins intends to produce hydrogen internal combustion engines in both the 15L and 6.7L displacements, believing that these engines enable the industry to reduce GHG emissions in this decade.

“Our customers are responding favorably to this practical technology,” said Jim Nebergall, general manager, hydrogen engines. “These engines look like engines, they sound like engines, and fit where engines normally fit.”

Cummins said key is pairing the engine with clean, zero-carbon hydrogen fuel.

“Reducing well-to-wheels carbon emissions requires innovation of both energy sources and power solutions,” said Srikanth Padmanabhan, president of Cummins’ engine business. “While use cases for battery-electric and fuel-cell-electric powertrains are promising, the pairing of green hydrogen in the proven technology of internal combustion engines provides an important complement to future zero-emissions solutions.”

Hydrogen internal combustion engines can use zero-carbon fuel at a lower initial price than a fuel-cell or battery-electric vehicle with little modification to today's vehicles, Cummins said.

Hydrogen Fuel Cell Trucks on the Way

However, that doesn’t mean Cummins is slowing down its hydrogen fuel-cell development. Cummins and Daimler Truck North America announced they are collaborating to upfit and validate Freightliner Cascadia trucks with a Cummins hydrogen fuel cell powertrain for use in North America.

A Cummins demonstrator truck at ACT Expo featured a fuel-cell and battery-electric power system. The truck was designed with vocational applications in mind, such as regional haul, urban delivery, port drayage, and terminal container handling.

The demonstrator truck uses a fuel cell electric powertrain that replaces a conventional internal combustion engine. The electric motor is powered by high-voltage batteries and fuel cell engines. As the vehicle is driven, the system operates the Cummins dual HD90 Fuel Cell Engines to dynamically manage the charge of the high-voltage batteries as required by the power load demands of vehicle operation. The energy storage includes seven hydrogen fuel tanks with a total of 32 kg of compressed hydrogen gas at 350 bar, and it is equipped with seven high-voltage batteries, each with 53.4 kWh of capacity providing a range of approximately 200 miles.

Don't Count Out Natural Gas

Nearer term, the natural-gas version of the 15L, the X15N, can help customers reach net-zero GHG emissions when paired with renewable natural gas and reduce NOx emissions, according to Cummins. This engine offers reduced package size and weight compared to diesel, and power and torque curves almost identical to diesel, according to the company.

"To date, Cummins has produced over 24,000 renewable natural gas engines, which provide immedaite carbon-negative benefits for the environment," said Tom Swenson, Cummins manager of global regulatory affairs, during a press conference. "Cummins has received overwhelmint interest in the 15-liter platform as a renewable fuels engine option."

The Cummins X15N will offer ratings up to 500 hp and 1,850 ft-lbs. of torque and will have a similar physical footprint as its existing 12L natural gas engine — but it weighs less than the existing 12L natural gas engine and about 500 pounds less than a comparable diesel engine. Cummins is actively working with major OEMs to integrate the engine. This engine is already performing well in global markets, Cummins said, and will arrive in production in the U.S. in 2024.

The range of a truck with a Cummins X15N natural gas engine will only be limited by the driver’s hours of service restrictions, as typical tank packages on natural gas trucks allow for at least 750 miles of driving between refueling, which can be accomplished in about 15 minutes.

Also at ACT Expo

B6.7 Propane:  This engine is the industry’s first purpose-built, medium-duty, turbocharged spark-ignited platform for propane fuels, according to Cummins. Built on the Cummins B-series platform, the B6.7 Propane is designed to deliver diesel-like durability and performance and a lower total cost of operation than currently available propane engines, the company said. The B6.7 Propane engine targets ultra-low NOx certification at launch, meeting both EPA and CARB emissions regulations for 2024 and 2027. Kenworth and Peterbilt already have announced the availability of the engine in medium-duty models.

Cummins Clean Fuel Technologies Fuel Systems: These natural gas fuel system configurations integrate with multiple body OEMs and include back of cab, front of body, side mount, roof mount and tailgate mount systems. Truck applications include refuse, over-the-road, construction, port, beverage delivery and more.

Terminal tractor featuring the PowerDrive 8000: This battery-electric system is designed to power terminal tractor applications in port, intermodal, and distribution markets. The components include a single direct drive traction motor, a system control module thermal management system and BP30E battery packs. The battery packs were also designed to meet the needs of terminal tractor duty cycles, including assisting operators to get through their 10- to 12-hour shifts. In the case a charge is needed, the vehicle is dc-fast charge compatible and can be at 85% state of charge in only 45 minutes.

Battery-electric school bus: More than 450 electric school buses are already on the road across the country, according to Cummins, which displayed a Cummins-powered Blue Bird electric school bus. Electric buses have a lower cost of maintenance than internal combustion engine buses, said the company, and provide zero tailpipe emissions when in use. A central charging location can be built out in a bus yard.