Westport Fuel Systems has developed a new fuel system that can burn hydrogen in heavy-duty internal combustion truck engines.

The new H2 HPDI fuel system is based on Westport’s HPDI fuel system technology, which allows heavy-duty trucks to run on biomethane (renewable natural gas) and natural gas with the same power, torque, efficiency, and performance as diesel engines, according to the company. Westport official said the company has achieved even better results by adapting the HPDI fuel system to run on hydrogen, all while meeting global emissions regulations.

HPDI fuel system technology uses compression ignition combustion, with the overwhelming majority of the energy derived from the combustion of, typically, a gaseous fuel, such as natural gas. Combustion is initiated via late-cycle direct injection of a small quantity of pilot fuel (diesel fuel, in the case of the H2 HPDI system), followed by direct injection of the primary gaseous fuel. Both fuels are injected via a proprietary dual concentric needle injector design. By using Diesel-Cycle thermodynamics, the HPDI fuel system retains the thermal efficiency, power, torque, and engine braking of the base diesel internal combustion engine, explained Scott Baker, vice president of engineering, in an online press conference on May 3.

“HPDI has long been established as matching diesel engine performance and efficiency,” Baker said. “And now we have demonstrated power, torque, and efficiency significantly exceeding that of the diesel base engine by migrating from natural gas HPDI to H2 HPDI. The advantage of HPDI combustion is that it retains the high compression ratio of the base diesel engine and does not suffer from engine knocking as the H2 is injected towards the end of the compression stroke just after pilot ignition and combustion begins."

Demonstrator Truck Showcases HPDI Hydrogen Technology

David Johnson, CEO of Westport Fuel Systems, said the H2 HPDI fuel system is installed in a fully functional demonstrator vehicle to show the ease with which a commercially available, production LNG HPDI system can operate on a zero-carbon fuel such as green hydrogen.

The H2 HPDI fuel system offers a cost-effective zero-carbon solution, he said, which delivers, tank to tailpipe, up to 98% CO2 reduction over diesel. This will allow manufacturers to leverage their investment in vehicle drivetrain design, supply chain and manufacturing by continuing to plan around low-carbon hydrogen internal combustion engines.

The H2 HPDI demonstrator truck will be on display at the 2022 ACT Expo in Long Beach, California, May 9-12.

“We believe H2 HPDI is compelling, with near-zero greenhouse gas emissions at a lower cost than fuel cell vehicles or battery electric vehicles, particularly for heavy-duty, long-haul trucking,” Johnson added. “We have developed the engine to utilize the capability of HPDI to deliver what is needed today in the marketplace, using hydrogen in place of natural gas, with development work happening at Westport Fuel Systems facilities, and through previously announced programs with AVL/TUPY, and Scania. And we expect new H2 HPDI programs with other partners to come soon.”

Johnson also noted that Westport has thousands of HPDI trucks on the road today, with the growth of HPDI sales in Europe averaging over 100% per year over the last three years.

“This is an incredible development,” Johnson continued. “The decarbonization of heavy-duty trucking has been especially challenging, because it has always been important to bring an affordable product to market that can be widely adopted at high scale, while delivering performance that is very similar to that of diesel-powered engines. And with H2 HDPI, we have a system that can deliver that performance in a cost-effective way to use gaseous fuels to reduce carbon emissions.”