Ethanol in gasoline fuel blends: Effect on fuel consumption and engine out emissions of SI engines in cold operating conditions

Ethanol is considered a clean and renewable alternative fuel for SI engines when used in blends with gasoline in different fractions to increase oxygen content, thus decreasing exhaust emissions of incomplete combustion products and dependency on fossil fuels. However, the scientific literature on fuel consumption and exhaust emissions of last generation SI engines during cold operating conditions and using ethanol/gasoline blends is far from comprehensive. In this experimental investigation, ethanol obtained from grape pomace was used in fuels prepared by blending it in increasing ratios (10, 20 and 30 vol.%) with oxygen-free gasoline. These ethanol/gasoline blended fuels were used to assess emissions and energy consumption of a motorcycle equipped with a large displacement four–stroke SI engine. Fuel consumption and exhaust emissions were measured during the cold transient over the execution of chassis– dynamometer tests, and calculated as a function of oxygen content of all ethanol/gasoline test fuels. Significant reductions in cold emission factors compared to the commercial gasoline were associated with well–defined percentages of ethanol content in gasoline fuel blends.