Korea's Hyundai and Kia, in collaboration with Volvo, are at the forefront of developing hydrogen combustion engines for vehicles, with a focus on delivering high performance and reducing emissions. Kia and Hyundai are dedicated to meeting the strict Euro 6d emissions standards while achieving a fuel efficiency of 50% in their new hydrogen engine. Their innovative system involves alkaline water electrolysis to produce carbon-free hydrogen, potentially revolutionizing green energy in transportation. Not limited to passenger vehicles, their future plans include implementing hydrogen systems in vans and trucks by 2027. Volvo, on the other hand, is concentrating on hydrogen-powered trucks to complement their renewable fuel and electric models. Their goal is to match diesel systems' performance with a 1,000km range and 300 kW power output from fuel cells, crucial for heavy haulage. Volvo's hydrogen systems feature HPDI technology to enhance energy efficiency and reduce consumption. The article also delves into the technology of hydrogen combustion engines, highlighting their established nature and current advancements for further improvements. These engines offer similar range and refueling times to traditional engines but emit significantly less carbon dioxide, aligning well with zero-emission objectives. Despite the positive aspects, challenges remain, including emissions from hydrogen combustion. Companies like Volvo are actively seeking solutions by using renewable materials to ensure emission levels comply with EU regulations. The article concludes by addressing FAQs about hydrogen combustion, discussing comparisons with traditional engines, top players in the market, the role of biodiesel, technological challenges, and environmental benefits. It emphasizes the significant positive impact of hydrogen combustion systems on reducing carbon emissions, which is a crucial step forward for the transportation industry as it moves towards more sustainable practices.