| 摘要: | 本研究是符合現行油品規範之九五無鉛汽油內摻3%乙醇之酒精汽油進行機車引擎排放多環芳香烴化合物（PAHs）排放特徵之研究，此外亦比對兩種市售九五無鉛汽油（C95-LFG）與（T95-LFG），均以四行程機車引擎動力計進行三種不同運轉條件之測試，同時以氣相層析質譜儀（GC/MS）進行分析廢氣中所含之多環芳香烴化合物之特性，就三種汽油之油品差異性對機車引擎，進行污染排放之比較。
研究結果顯示單汽缸四行程機車引擎分別使用三種九五無鉛汽油排放之各項比較如後：排放廢氣之總PAHs濃度平均值以C95-LFG（3320μg/Nm3） 為最高，其平均值分別為T95-LFG（2130 μg/Nm3）之1.56倍及C95E3（1940 μg/Nm3）之1.71倍；在單位耗油量之排放係數，C95-LFG（139000 μg/L-fuel）為最高其平均值分別為T95-LFG（83600 μg/L-fuel）之1.66倍，C95E3 （68600 μg/L-fuel）之2.03倍。比較單位行駛距離之排放係數C95-LFG(1470 μg/km) 為最高其平均值分別為T95-LFG(891μg/km) 之1.65倍及C95E3(817 μg/km)之1.80倍。
單汽缸四行程機車引擎排放廢氣之PAHs總BaPeq之濃度平均值方面，由高而低依序：C95-LFG （12.5 BaPeq μg/Nm3）為最高，C95E3與T95-LFG同為10.4μg BaPeq/Nm3；在單位耗油量PAHs之總BaPeq 排放係數平均值由高而低依序：C95-LFG（537 BaPeq μg/L-fuel）為最高、T95-LFG（400μg BaPeq/L-fuel）其次、C95E3（390 BaPeq μg/L-fuel）次之。在單位行駛距離PAHs之總BaPeq排放係數平均值由高而低依序：C95-LFG（5.17 BaPeq μg/km）為最高，而C95E3（4.63 BaPeq μg/km）次之，T95-LFG（3.95 BaPeq μg/km）為最低。
在單汽缸四行程機車引擎燃燒不同油品時，絕大部分之PAHs均在引擎內之燃燒過程中被分解，而添加酒精汽油對於PAHs排放量具有減量之趨勢，此外PAHs之總BaPeq 排放係數減量上並無規律性，且有部分增加排放量，但影響環境與人體健康之危害風險因子有增加趨勢值得國人重視，本研究可作為日後推廣替代能源政策及相關法令規章提供一項研究參考。
The emission characteristics of Polycyclic Aromatic Hydrocarbons（PAHs） exhaustion of motorcycle engine, while blending the lawful 95-leadfree base gasoline with alcohol in 3% ethanol, is the theme of the research. Besides, the comparison of two 95-leadfree gasolines on the market (C95-LFG, T95-LFG) will be tested under three different rotation conditions of four-stroke motorcycle; meanwhile, the characteristics of PAHs containing in the exhaustion, and the analyses of the difference of three different gasoline applying for engine will be proceeded with the GC/MS simultaneously to compare the pollutant exhaustion.
The study that respectively using three different 95-leadfree gasoline for single-cylinder, four-stroke engine shows the facts as followings: the C95-LFG got the highest PAHs concentration average(3320 µg/Nm3), which is 1.56 times of T95-LFG(2130 µg/Nm3), and 1.71 times of C95E3(1940 µg/Nm3); C95-LFG got highest LFC coefficient(139000 µg/L-fuel), which is 1.66 times of T95-LFG (83600 µg/L-fuel), and 2.03 times of C95E3(68600 µg/L-fuel); C95-LFG got the highest driving distance coefficient(1470 µg/km), which is 1.65 times of T95-LFG(891 µg/km), and 1.80 times of C95E3(817 µg/km).
In the aspect of concentration average of PAHs of BaPeq in the exhaustion of the single-cylinder, four-stroke engine, C95-LFG got the highest (12.5 BaPeq µg/Nm3), and T95-LFG and C95E3 got the same results (10.4 BaPeq µg/Nm3). For the PAH emission factor, C95-LFG(537 BaPeq µg/L-fuel) is the highest, T95-LFG(400 BaPeq µg/L-fuel) is the second one, and C95E3(390 BaPeq µg/L-fuel) got the lowest. In the aspect of driving distance coefficient, C95-LFG(5.17 BaPeq µg/L-fuel) got the highest, C95E3 (4.63 BaPeq µg/L-fuel) is the second one, and T95-LFG(3.95 BaPeq µg/L-fuel)got the lowest.
While the single-cylinder, four-stroke engine consumes different kind of fuels, most of PAHs are disassembled during the combustion process, and PAHs exhaustion amount has the tendency of reduction while adding alcoholic gasoline. In addition, it is irregular that the PAHs coefficient decreases, or sometime the exhaustion increases. The rising tendency of risk factors which may affect environment and human health deserves the regards of our country fellows. This research can be the reference for promoting substitute energy and enacting law concerned. |
