The use of ethanol (ethyl alcohol) as a fuel for spark ignited (Sl) internal combustion engines has been evaluated and considered satisfactory since the early1 900s. Today due to the increasing cost of petroleum and the current world oil uncertainty, which may greatly affect the future availability of petroleum, some alternative fuels for internal combustion engines are needed. Ethanol is one of the fuels that has shown promise as a petroleum substitute. Today the country of Brazil has chosen a path of less dependence on petroleum by developing an ethanol fuel technology. In the spring of 1980, cars designed to run exclusively on ethanol were offered for sale to the Brazilian public. Brazil has also encouraged its citizens to use ethanol by making it available to the consumer at half the cost of gasoline.

This paper reviews the use of ethanol as an unmixed fuel for internal combustion engines. Anhydrous ethanol (no water present) is required when fuel mixtures are made with gasoline or diesel fuel. Presence of greater than 1.5% water in ethanol will cause separation of the ethanol from the petroleum fuel. On-farm production of ethanol will yield ethanol fuel with at least 5% water present or up to 50% water present. Thus, on-farm ethanol fuel product ion would necessitate adapting internal combustion engines for use of unmixed ethanol fuel.

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