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The literature on hydrogen fueled internal combustion engines is surprisingly extensive and papers have been published continuously from the 1930's up to the present day. Ghent University has been working on hydrogen engines for more than a decade. A summary of the most important findings, resulting from a literature study and the experimental work at Ghent University, is given in the present paper, to clarify some contradictory claims and ultimately to provide a comprehensive overview of the design features in which a dedicated hydrogen engine differs from traditionally fueled engines. Topics that are discussed include abnormal combustion (backfire, pre-ignition and knock), mixture formation techniques (carbureted, port injected, direct injection) and load control strategies (power output versus NOx trade-off).

Hydrogen is seen as one of the important energy vectors of the next century. Hydrogen as a renewable energy source, provides the potential for a sustainable development particularly in the transportation sector. Hydrogen-driven vehicles reduce both local as well as global emissions. The laboratory of transport technology (University of Gent) converted a General Motors Corporation/Crusader V-8 engine for hydrogen use. Once the engine is optimized, it will be built in a low-floor midsize hydrogen city bus for public demonstration. For a complete control of the combustion process and to increase the resistance to backfire (explosion of the air-fuel mixture in the inlet manifold), a sequential timed multipoint injection of hydrogen and an electronic management system is chosen. The results as a function of the engine parameters (ignition timing, injection timing and duration, injection pressure) are given.

Methanol fueled spark ignition (SI) engines have the potential for very high efficiency using an advanced heat recovery system for fuel reforming. In order to allow simulation of such an engine system, several sub-models are needed. This paper reports the development of two laminar burning velocity correlations, corresponding to two reforming concepts, one in which the reformer uses water from an extra tank to produce hydrogen rich gas (syngas) and another that employs the water vapor in the exhaust gas recirculation (EGR) stream to produce reformed-EGR (R-EGR). This work uses a one-dimensional (1D) flame simulation tool with a comprehensive chemical kinetic mechanism to predict the laminar burning velocities of methanol/syngas blends and correlate it. The syngas is a mixture of H2/CO/CO2 with a CO selectivity of 6.5% to simulate the methanol steam reforming products over a Cu-Mn/Al catalyst.

Hydrogen-fueled internal combustion engines equipped with port fuel injection offer a cheap alternative to fuel cells and can be run in bi-fuel operation side-stepping the chicken and egg problem of availability of hydrogen fueling station versus hydrogen vehicle. Hydrogen engines with external mixture formation have a significantly lower power output than gasoline engines. The main causes are the lower volumetric energy density of the externally formed hydrogen-air mixture and the occurrence of abnormal combustion phenomena (mainly backfire). Two engine test benches were used to investigate different means of compensating for this power loss, while keeping oxides of nitrogen (NOx) emissions limited. A single cylinder research engine was used to study the effects of supercharging, combined with exhaust gas recirculation (EGR). Supercharging the engine results in an increase in power output.

Using liquid alcohols, such as methanol and ethanol, in spark-ignition engines is a promising approach to decarbonize transport and secure domestic energy supply. Methanol and ethanol are compatible with the existing fuelling and distribution infrastructure and are easily stored in a vehicle. They can be used in internal combustion engines with only minor adjustments and have the potential to increase the efficiency and decrease noxious emissions compared to gasoline engines. In addition, methanol can be synthesized from a wide variety of sources, including renewably produced hydrogen in combination with atmospheric CO₂. Presently, during the production of ethanol or methanol a dehydration step is always applied. This step accounts for a significant part of the entire production process' energy consumption and thus, from an economical point of view, methanol and ethanol could become more interesting alternative fuels if the costs related with dehydration could be reduced.