Cummins and its technology partners have completed a significant milestone by developing hydrogen internal combustion engine technology for commercial vehicles, primarily targeting medium-duty trucks and buses. Led by Cummins, Project Brunel brought together Johnson Matthey, PHINIA, and Zircotec to deliver a 6.7-litre hydrogen internal combustion engine that offers improved performance and durability. The project, which received match-funding from the UK Government through the Advanced Propulsion Centre UK, aimed to reduce carbon emissions and enhance air quality impact in heavier-duty applications. The hydrogen engine concept, based on Cummins' proven spark-ignited engine platform, incorporated innovative technologies from PHINIA, Johnson Matthey, and Zircotec. This collaborative effort resulted in more than a 99% reduction in tailpipe carbon emissions and ultra-low NOx compared to current diesel engine standards. The project showcased the potential of hydrogen internal combustion engine technology in meeting efficiency, performance, and emissions reduction requirements for decarbonizing commercial vehicles. The partners emphasized the scalability of the 6.7-litre engine design to heavy-duty applications and highlighted Cummins' ongoing development of a 15-litre hydrogen internal combustion engine for heavy-duty vehicles. Additionally, Cummins' investment in a new Powertrain Test Facility at its Darlington Campus underlines the company's commitment to advancing sustainable powertrain solutions. The project participants expressed optimism about the market success of hydrogen internal combustion engines and the potential for the UK to become a leader in H2-ICE manufacturing and export.