Southwest Research Institute said it had completed a spark-ignited hydrogen internal combustion engine for medium-duty commercial vehicles.
“In addition to decades developing medium- and heavy-duty engines, SwRI has some of the most extensive experience in the world developing and testing H₂-ICEs for internal research, clients and industry demonstrations. The engine was designed, constructed and rigorously tested at SwRI to ensure efficiency and performance,” — Qilong Lu, a program manager in SwRI’s Powertrain Systems Engineering Department and one of the project leads.
The institute worked with a commercial client and selected Tier 1 suppliers for two years. Development moved from a single-cylinder unit to a multi-cylinder engine that can be installed in a medium-duty truck chassis.
“We began at the single-cylinder level, focusing on optimizing combustion and injection strategies. From there, our team ramped up efforts to develop the full multi-cylinder engine, addressing key challenges such as pre-ignition, combustion stability and overall systems integration,” — Qilong Lu.
Modified intake-port geometry is tailored to hydrogen’s faster combustion speed. A larger intake valve improves cylinder filling, dedicated injectors enhance combustion, and a turbocharger provides diesel-like torque.
The engine is based on a pent-roof combustion-chamber design previously used for gasoline but optimized for hydrogen. SwRI designed and calibrated its engine-control system.
“The project brought together many areas and experts at the Institute to complete. SwRI’s hydrogen combustion engine program is working every day to advance this technology and showcase its potential as a near-zero carbon emissions industry solution,” — Chris Bitsis, assistant director of SwRI’s Powertrain Systems Engineering Department.
SwRI says the engine delivers diesel-like characteristics and performance while producing near-zero tailpipe CO₂ emissions. The institute is continuing research into hydrogen energy and decarbonization technologies.
