Mercedes-Benz Special Trucks and Mörtlbauer Baumaschinen Vertriebs GmbH recently unveiled two innovative prototypes as part of the 'WaVe' development project in Germany. The project focused on researching hydrogen combustion engines for special-purpose vehicles, resulting in the successful demonstration of the Unimog test vehicle and crawler at the Mörtlbauer factory premises. Over a three-year period, the collaboration between Mercedes-Benz and Mörtlbauer, along with 16 other partners, led to the development of hydrogen combustion engines that showed promising results. The Unimog implement carrier and the dump truck crawler, both equipped with medium-duty engines converted for hydrogen propulsion, showcased their capabilities during driving and working operations. These prototypes have been extensively tested, with the Unimog undergoing various tests for over a year and the dump truck crawler proving effective since spring 2024. The event marked the successful conclusion of the project, highlighting the potential of hydrogen combustion for high-power work machines. The demonstrators, featuring customised pistons, hydrogen-compatible intake systems, and optimised ignition systems, produced water as a byproduct, emitting hot steam via the exhaust system. The Unimog and the crawler were designed to be easily refueled with gaseous hydrogen, offering comparable engine output to diesel engines. The 'WaVe' project, which began in 2021 and received funding from the German government, emphasized the development of a hydrogen-based drive system for working machines, with the aim of replacing conventional diesel engines. These advancements in hydrogen combustion engines not only reduce emissions but also enhance the efficiency of special-purpose vehicles. The success of this project signifies a step towards more sustainable industrial applications, with the potential for series production of hydrogen-powered vehicles. The collaboration between industry and science partners has paved the way for a future where hydrogen combustion engines play a significant role in driving environmental sustainability and innovation in the automotive sector.