| 摘要: | 本研究使用不同比例異辛烷與車用汽油進行引擎排放多環芳香烴特徵之研究，其中燃料油品包括九二及九五無鉛基礎油(95-LFBG及98-LFBG)(不含MTBE)、添加10％體積比異辛烷之92-LFBG (92A)、20％(92B)、30％(92C)、40％(92D)、50％(92E)、添加10％異辛烷之95-LFBG (95A)、20％(95B)及30％(95C)，分別在三種不同操作條件下，針對每種燃料油之引擎排放廢氣中21種PAHs進行三次採樣及分析，分析儀器為GC/MS。
研究結果顯示，92E引擎排放總PAHs濃度為六種九二油品中最低者(6452 μg/Nm3)，分別為、92-LFBG (11127 μg/Nm3) 、92A (10520 μg/Nm3) 、92B (9349 μg/Nm3) 、92 C(8387 μg/Nm3)及92D(6712 μg/Nm3)引擎之0.579、0.613、0.690、0.838、及0.961倍，而九五汽油引擎排放廢氣濃度則以95 C(10828 μg/Nm3)最低，分別為95-LFBG (12840 μg/Nm3)、95A (12126 μg/Nm3)及95B (11688 μg/Nm3)之0.843、0.892及0.926倍。
比較九二及九五之單位耗油量之總PAHs排放係數，六種九五無鉛基礎汽油由高而低排序為92-LFBG > 92A> 92B> 92C> 92D> 92E。而在四種九五無鉛汽油引擎單位耗油量總PAHs排放係數：95-LFBG>95A >95B >95C，而在不同操作條件下所有的油品引擎單位行駛距離之排放係數皆以30km/hr之狀態最高，以50km/hr之操作條件下最低。
異辛烷添加劑對汽油引擎排放PAHs特徵之影響，引擎總PAHs排放係數隨異辛烷之添加量之增加而降低，亦使單位耗油量之PAHs排放係數之BaPeq隨之降低。
The fuels with different fraction of Isooctane were used to investigated the emission of PAHs (Polycyclic Aromatic Hydrocarbons) from the gasoline engine. These fuels included 92-Leadfree Base Gasoline (92-LFBG), 95-Leadfree Base Gasoline (95-LFBG), 92-Leadfree Gasoline containing 10% Isooctane (92A), 92-Leadfree Gasoline containing 20% Isooctane (92B), 92-Leadfree Gasoline containing 30% Isooctane (92C), 92-Leadfree Gasoline containing 40% Isooctane (92D), 92-Leadfree Gasoline containing 50% Isooctane (92E), 95-Leadfree Gasoline containing 10% Isooctane (95A), 95-Leadfree Gasoline containing 20% Isooctane (95B) and 95-Leadfree Base Gasoline containing 30% Isooctane (95C). The engine was simulated for the idling condition and the cruising speed at 30 and 50km/hr.The samples with twenty one individual PAHs emitted from the engine powered by each fuel was taken by three times on each conditions. The samples were analyzed by a gas chromatography/mass spectrometer (GC/MS).
The results of this study were summarized as follows. For the emission of total-PAH concentration, among six 92-leadfree fuels, the highest one is that of 92A engine (6452 μg/Nm3), which is 0.579and and 0.613 and 0.690 and 0.838 and 0.961 times of magnitude lower than that emitted from 92-LFBG and 92A and 92B and 92C and 92D and92E powered engines, respectively. Among the 95-leadfree fuel, the highest total-PAH concentration of engine emission was 95C, which is 0.843 and 0.892 and 0.926 times of magnitude higher than that emitted from 95-LFBG and 95A and 95Bengine, respectively.
The emission factor per liter fuel consumption of 95-LFBG,The sequence of total-PAH emission factor per kilometer of traveling for 92- and 95-leadfree fuel engines were 92-LFBG>92A >92B >92C >92D >92E and 95-LFBG > 95A > 95B>92C, respectively.Under 3 different operation conditions, the 30km/hr condition was found to have highest total-PAH emission factor and the 50 km/hr condition showed with the lowest one.
The effect of Isooctane on the PAH emission showed that a higher amount of Isooctane adding in gasoline will result in a lower total-PAH emission factor of the gasoline engine.Though the BaPeq of LM-PAHs is relatively low, the risk of LM-PAHs should not be ignored due to their high concentration in the engine exhaust. |
