本研究主要乃探討在台灣地區之汽油引擎使用九五無鉛3%酒精汽油，瞭解其尾氣排放法規污染物及多環芳香烴化合物之排放特性，建置汽車群族其法規污染物及多環芳香烴化合物之排放係數資料庫，並且比較冷熱啟動測試、市區行駛型態(FTP-75)及高速公路行駛型態(HWFET)方式之汽車尾氣排放特性之差異。
研究結果顯示在市區行駛型態測試條件下對基礎無鉛汽油、市售無鉛汽油與E3酒精汽油於汽車引擎排放廢氣中全程之總PAHs濃度而言，95-LFBG(1260μg/Nm3)平均分別為95-E3、95-LFG之1.32、1.60倍。就單位油耗量之總平均排放係數以95-LFBG(239mg/L-fuel) ﹥95-E3(206mg/L-fuel) ﹥95-LFG(167mg/L-fuel) 。
對於符合不同環保標準之車輛於FTP-75測試條件下，其全程排放廢氣中之總PAHs濃度而言，符合二期環保標準之二期車輛平均為1120μg/Nm3 (95-LFG)、1450μg/Nm3(95-E3)，而符合三期標準之車輛平均為646μg/Nm3 (95-LFG)，680μg/Nm3(95-E3)，且比較使用95-E3之汽油引擎分別為95-LFG之1.30、1.05倍。顯示對於使用3%酒精汽油三期車輛較二期車輛適合。
含氧添加劑乙醇對汽油引擎排放PAHs特徵之影響，引擎總PAHs濃度及排放係數對於添加3%乙醇之酒精汽油是呈現增量之效果，但對於部分三期車輛具有減量之效果。 This study is to assess the generation or depletion on air pollutants including CO, HCs and polycyclic aromatic hydrocarbons (PAHs) emission from gasoline-powered engines fueled commercial 95-leadfree gasoline (95-LFG), 95-leadfree base gasoline (95-LFBG) and 95-LFBG blended with 3% alcohol (95-E3), respectively. More Than 12 test vehicles were operated and simulated by USEPA Federal Test Procedure (FTP-75) modes with standard cold-start, hot-soak, and highway fuel economy test driving schedule. EPA has decided to modify the gasoline specification; therefore, 3% alcohol will be added in gasoline to reduce the air pollutants as previous assessment in Taiwan. However, adding ethanol in gasoline was the tide for the sake of environmental reason. The pollutant emitted from gasoline-powered engines in Taiwan is a serious issue.
More than different 10 automobiles were tested and gaseous and particle-bound PAH samples were collected after traditional pollutant sampler. A gas chromatograph/mass spectrometer (GC/MS) was employed to analyze 21 individual PAHs emitted from the exhaust of engines. The total PAHs and their BaPeq emission characteristics was also estimated and calculated by BaP toxic equivalent factor (TEF).
In this study, emitted by 95-LFBG powered engine had highest total PAHs concentration for 1260 g/Nm3. The other gasoline-powered engines had 7640 g/Nm3 (95-E3), 786 g/Nm3 (95-LFG) under FTP-75 operation condition. For the PAH emission factor in fuel consumption unit, the sequence was 95-LFBG (239 mg/L-fuel), 95-E3 (206 mg/L-fuel) and 95-LFG (167 mg/L-fuel). Under the different EPA phase regulation on the emission of automobile, the total PAH emitted from Phase II vehicles were 1120 g/Nm3 (95-LFG) and 1450 g/Nm3 (95-E3). In the same time, the total PAH emitted from Phase III vehicles were 646 g/Nm3 (95-LFG) and 680 g/Nm3 (95-E3).
From the results of this study, gasoline with 3% ethanol may reduce CO and HCs due to its oxygen content, however, there is no significant effect on the depletion of PAH emission. Furthermore, adding more alcohol in gasoline should be assessed under this operation condition.
