本研究主要目標為探討台灣地區行駛中車輛使用酒精汽油時之適用情況，針對不同比例(2%與5%)之酒精汽油及不同摻配(內含與外掺)方式之酒精汽油進行實車測試。七部測試車輛依其型式分為轎車與商旅車分別進行實驗，並以市區行駛型態(FTP-75)之條件進行動力計檢測。氣相與粒狀物相之PAHs與BaPeq樣品之採集以車輛尾氣直接採樣方式取得，樣品經索氏萃取、淨化與濃縮處理後，最後以氣相層析質譜儀(GC/MS)進行定性與定量分析。車輛排放廢氣中亦同時進行傳統性空氣污染物(THC、CO、NOX、NMHCS與CO2)之排放分析。
研究結果顯示，所有測試車輛使用市售九五無鉛汽油時，車輛引擎排放廢氣之總PAHs平均濃度以商旅車型(1840 μg/Nm3)高於轎式車型(1460 μg/Nm3)，其平均總BaPeq濃度則分別為168及154 μgBaPeq/Nm3。而使用不同酒精汽油後，車輛引擎排放廢氣總PAHs濃度可達到1.5 ~ 55%之削減效果，而總BaPeq削減效果可達到1.0 ~ 18%。研究中亦發現，測試車輛在使用市售九五無鉛汽油時，其引擎排放PAHs濃度較高者，使用酒精汽油後有明顯之削減效果最高可達81%；相同比例且不同摻混方式之酒精汽油PAHs減量效果則以外部添加方式優於內部掺混。車輛排放傳統性污染物與PAHs之相關性分析，以THC與CO之線性相關較為明顯。 This study is to assess the generation and depletion on air pollutants including THC, CO and polycyclic aromatic hydrocarbons (PAHs) emission from In-Used gasoline-powered engines fueled commercial 95-leadfree gasoline (95-LFG), 95-LFG external blended with 2% ethanol (EX-E2), 95-LFG external blended with 5% ethanol (EX-E5) and 95-LFG internal with 5% ethanol (IN-E5) , respectively. More Than 7 test vehicles were operated and simulated by USEPA Federal Test Procedure (FTP-75) modes with cold transient phase, stabilized and hot transient phase. EPA has decided to modify the gasoline specification; therefore, ethanol gasoline will be 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 7 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, automobiles use 95-LFG fuel emitted by recreation vehicle engine had high total PAHs concentration for 1840 mg/Nm3 and total BaPeq concentration for 168 μgBaPeq/Nm3；The saloon gasoline-powered engines had 1460 mg/Nm3 and total BaPeq concentration for 154 μgBaPeq/Nm3, under FTP-75 operation condition.Automobiles used ethanol gasolines, total PAHs concentration depletion attain 1.5 ~ 55% and total BaPeq concentration attain 1.0 ~ 18%.
From the results of this study, ethanol gasoline may reduce PAHs, BaPeq, THC and CO due to its oxygen content. More than 2 type ethanol gasoline were 95-LFG external blended with ethanol better than 95-LFG internal with ethanol.
Keyword: PAHs, FTP-75, ethanol gasoline, and gasoline-powered engine.
