Alternative fuels in medium-speed diesel engines. Volume II. Synthetic fuels, alcohol emulsions, off-specification fuels and methanol

This report describes the second year of research activity of an ongoing research, development and demonstration effort to investigate the use of alternative fuels in medium-speed diesel engines. The first year of the project (Phase I) is the subject of an earlier report available through NTIS. Tests were performed in laboratory medium-speed diesel engines to define the ability of these engines to operate on alternative fuels, the fuel property limits that the engines can tolerate, and the problems associated with alternative fuels use. Low cetane number and high viscosity petroleum fuels were tested to define the tolerance limits of these properties. Attempts were made to improve low cetane number fuel performance through minor engine modifications and adjustments. Also tested were alcohol-in-diesel fuel emulsions, synthetic fuels, and low proof ethanol. Both methanol and ethanol were consumed in stabilized and unstabilized emulsion forms. The synthetic fuels included a PARAHO shale oil marine diesel fuel, and solvent refined coal (SRC II) liquid fuel. The engines were capable of operating on all of these fuels, demonstrating their versatility. In the case of poor ignition quality fuels, dual-fueling provided a suitable ignition source. Performance and combustion characteristics were frequently equal to normal diesel fuel levels.