Hydrogen Large Bore Engine Technology – More than a Bridging Technology

With regards to reducing greenhouse gas emissions, CO₂-neutral fuels such as hydrogen, ammonia, methanol and synthetic liquified natural gas (sLNG) play a decisive role, especially for shipping and various off-road applications. In addition to the possibility of energy conversion of hydrogen into fuel cells, hydrogen combustion engines offer a number of practical advantages, such as the use of existing technology modules as the basis for robust solutions for propulsion systems at a considerable cost advantage. The present paper starts with the motivation, describing that hydrogen is part of the goals and not only a bridging fuel. In the second part, the challenges in engine operation with hydrogen on the engine design and charging are briefly described. On the third section, measurement results of test series with hydrogen combustion and H₂ natural gas mixtures on medium-speed large engines are compared and evaluated with engine results carried out with pure natural gas operation. The achieved mean indicated pressures at two different compression ratios are discussed. With lowered compression ratio, detailed results such as emissions, load increase at constant hydrogen content and hydrogen variation at constant load are described. The limits of combustion phenomena’s are described in two examples. Finally, an outlook on further development activities with regard to CO₂-neutral fuel alternatives is given.