Abstract
Since the oil crisis in the 70s and continuing with awareness of the need to find alternatives to traditional fuels in the early 90's so interested in selling gas companies and manufacturers of industrial engines, internal combustion, sought to find solutions for using natural gas as replacement of traditional fuels. Thus came into being different associations such as ASUE in Germany in 1977 Arbeitsgemeinschaft für Sparsame one Umweltfreundlichen Energieverbrauch.
Keywords: methane number, wobbe index, diesel engine, gaseous fuels