UNBURNED ALCOHOL, LEGISLATED EMISSIONS AND OZONE FORMING POTENTIAL FROM A CAR FUELED WITH A22 GASOLINE, A85 GASOLINE OR PURE ETHANOL (HER)

摘要

Some countries such as the USA and Brazil have started to control non-methane organic gas (NMOG) emissions, including both the NMHCs and oxygenates, which comprise the alcohols and carbonyls that are contained in the exhaust. With the rapid increase in the number of Flex Fuel vehicles on the market over the last few years, ethanol consumption has also increased. As a consequence, substantial amounts of unburned alcohol are expected to be present in vehicle gas emissions. The objective of this work was to measure the unburned alcohol, legislated emissions and ozone precursor emissions from a passenger car fueled with either different gasoline blends or pure hydrated ethanol (HER). The car was tested in a chassis dynamometer according to the Brazilian standard NBR6601, which test cycle is similar to the FTP 75. The car was fueled with gasoline containing 22% ethanol (A22), 85% ethanol (A85), or pure hydrated ethanol (HER). Legislated emissions, such as HC, CO, NO_x, CO_2, and CH_4 were measured using a Horiba 7000 series bench. Evaporative emissions, however, were outside the scope of this paper. Aldehydes were measured by high performance liquid chromatography (HPLC) according to the Brazilian standard NBR12026. Unburned alcohol was measured using two different techniques: FTIR analysis and gas chromatography. In addition, ozone precursor formation was measured using an ozone analyzer (model 49i) from Thermo Scientific. The main conclusion was that unburned alcohol emissions increase in direct proportion to the ethanol in the fuel. Thus, if alcohol-fueled vehicles are widely used, the effect of unburned alcohol on air quality cannot be ignored. The same trend was observed for HC, CH_4, NMHC, CO and aldehyde emissions. CO_2 emissions decreased with ethanol content. Ozone generation increased with exposure to radiation from sunlight.