Für die Anwendung für mittlere und schwere Nutzfahrzeuge stellen Erdgasmotoren eine wirtschaftlich interessante Antriebsstranglösung als Alternative zum Dieselmotor dar. Die Kombination aus langfristig niedrigem Erdgaspreis sowie staatlichen und lokalen Subventionen für treibhausgasreduzierende Antriebslösungen stellen für Flottenbetreiber oft überzeugende Argumente dar, um den Umstieg von Diesel- auf Erdgasantrieb zu forcieren. Darüber hinaus führt der stetig wachsende Straßentransportsektor trotz immer effizienterer Antriebstechnologien zu steigenden CO2-Emissionen.

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.

High-speed engines are set to be the main power source for decentralized power generation, commercial and high-performance marine, Oil&Gas service, Rail as well as for construction equipment (C&I). Considering the projection, that next generation highspeed engines will be operated much more in integrated systems and hybridized applications, the thermal efficiency of the combustion engine will still be in the main focus of new engine developments.

Natural gas vehicles are a mature technology already available today for solving the environmental problems caused by the automobile. The advantage is based on the features of the main fuel content methane. While keeping a minimum fuel quality standard, it is doesn’t matter to the vehicle technology whether the Methane is several million years old or just a few days. There is complete compatibility between fossil and renewable sources for this most simple of all hydrocarbons. Its highest possible ratio between hydrogen and carbon and the resulting features considering production/availability (fossil & renewable), the justifiable effort in the fuel system and the engine and environmental features make methane an ideal vehicle fuel.

Several alternative combustion processes are being studied as options for reducing the emissions of nitrogen oxide (NOx) and soot of direct injection (DI) diesel engines. Such processes are characterised by adequate combustion control that helps to avoid areas of high local flame temperatures, which lead to NOx formation, and fuel rich combustion areas which promote soot formation. In most cases, this will be achieved by a complete or partial charge homogenisation prior to combustion. Four processes of alternative combustion control have been applied to a single-cylinder research engine and compared to conventional diesel combustion. By means of adequate measurement techniques and engine cycle simulation, the combustion processes were subjected to an exact thermodynamic analysis in terms of mixture formation, combustion and wall heat transfer and assessed for their potential relating to emissions, efficiency and load limits.