不同品质燃油对公交车道路颗粒排放特征的影响

Effects of Different Fuels on Real-World Particle Number Emissions from a Bus

以国Ⅳ排放柴油公交车为样车,研究了3种燃油公交车的颗粒数量排放特性.3种燃油分别为纯柴油、B20燃油〔V(生物柴油)∶V(纯柴油)=2∶8〕和G20燃油〔V(天然气制油)∶V(纯柴油)=2∶8〕.结果表明:公交车燃用3种燃油的排气颗粒数量随粒径变化均呈双峰对数分布,其中核态颗粒数量峰值粒径均为10.8 nm;聚集态颗粒数量峰值粒径则因燃料差异而不同,其中纯柴油、B20燃油和G20燃油分别为80.6、69.8和60.4 nm.对于不同类型道路,在公交车燃用纯柴油时,其快速路下的排气颗粒数量(7.35×1015km-1)最低,分别比主干道和次干道低47.7%和55.1%.对于不同品质燃油而言,在全程测试线路内,燃用G20燃油的公交车排气颗粒总数量(6.92×1015km-1)最低,较纯柴油和B20燃油分别降低了42.5%和32.4%.其中,G20燃油排气中核态颗粒数量为1.81×1015km-1,较纯柴油和B20燃油分别降低了3.1%和15.4%,而聚集态颗粒数量则分别降低了49.7%和37.0%.表明公交车燃用天然气制油可有效降低颗粒排放.

Real-world particle number emissions from a China Ⅳ diesel bus fueled with three different fuels were studied.The fuels included neat diesel fuel,B20 fuel（ 20% biodiesel ＋ 80% diesel fuel by volume） and G20 fuel（ 20% gas to liquid ＋ 80% diesel fuel by volume）.The results showed that size distributions of particle number concentration of the bus fueled with the three fuels were bimodal.The peak value of the nucleation mode particle size was 10.8 nm in diameter,while the peak value of the accumulation mode particles varied between the fuel types： 80.6 nm（ neat diesel）,69.8 nm（ B20 fuel） and 60.4 nm（ G20 fuel）.Under different road conditions,the bus fueled with neat diesel had the lowest particle number concentration on a fast road,7.35 × 10^15 particles per kilometer,which was lower by 47.7% and 55.1%,respectively,than the results on a main road and secondary road.For different fuels,the bus fueled with G20 fuel had the lowest particle number concentration with 6.92 × 10^15 particles per kilometer on the entire road,which was lower by42.5% and 32.4% compared with the neat diesel and B20 fuel,respectively.Among the particles,for the nucleation mode particles,the number concentration was 1.81 × 10^15 particles per kilometer,lower by 3.1% and 15.4% than neat diesel and B20 fuel,while for the accumulation mode particle number,the concentration was lower by 49.7% and 37.0%,respectively.This indicates that the gas-toliquid fuel can effectively reduce the particle emissions from diesel buses.