Browse Publications Technical Papers 2007-01-4005

Effects of Ethanol or ETBE Blending in Gasoline on Evaporative Emissions for Japanese In-Use Passenger Vehicles 2007-01-4005

Biomass derived ethanol is thought to be a promising gasoline blend stock to reduce carbon dioxide (CO2) emissions from vehicles, and its practical use is under discussion. In Japan, the maximum permissible limit of ethanol content in gasoline is 3 vol%, which almost corresponds to 1.3 mass% of oxygen content, which is defined by gasoline quality standards at present. In addition to ethanol, the use of Ethyl tert-Butyl Ether (ETBE), which is synthesized from biomass ethanol and isobutene, is under discussion as a kind of biomass fuels in Japan.
This study examines and discusses the effects of ethanol- and ETBE-blended gasolines on evaporative emissions, especially on refueling loss and diurnal breathing loss (DBL) emissions, from in-use passenger cars in Japan. This study shows that refueling loss emissions don't increase with ethanol- or ETBE-blended gasoline as long as Reid Vapor Pressure (RVP) is adjusted. However, DBL emissions significantly increased with 3vol% ethanol-blended gasoline (E3 gasoline), compared to base gasoline (non-oxygenated gasoline) or ETBE blended gasoline, even though RVP of each fuel was adjusted to within similar levels. The effects of ethanol-blended gasoline on evaporative emissions were studied from the view point of vapor composition. As a result, the increased DBL emissions with ethanol-blended gasoline were presumed to be caused by permeation through vehicle fuel systems.


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