Fuels With a High Enthalpy of Evaporation in Si Engine

The increasing use of fuels derived from oil, deepens concern about the fact that non-fossil fuels have to be considered as the fuels of the future. Among the alternatives, hydrogen produced from the abundant sources of water, seems to be one of the best, but it suffers drawbacks with regard to combustion, storage and transportation. The other alternatives are ammonia, produced from unlimited sources of air and water [1], methanol from coal and ethanol from agricultural sources. For operation of the internal combustion engine, lower air-fuel mixture temperature or higher air-fuel mixture pressure are often preferred, because they provide a higher volumetric efficiency and consequently a higher power output. The air-fuel mixture temperature is greatly affected by evaporation enthalpy of the liquid fuel introduced into the inlet manifold of a spark-ignition engine. Due to the very low air-fuel mixture temperature for a fuel such as ammonia, the fuel's change of state may be observed in the inlet manifold. This has a significant role in the operation of the engine. These factors are examined in this paper using related theoretical and experimental results.