柴油机燃用正庚烷及柴油时多环芳香烃与碳烟的演化规律

基于电控燃油喷射柴油机的全气缸取样系统,使用气相色谱-质谱联用仪及程序升温大体积进样方法,对柴油机燃用正庚烷和柴油过程中缸内多环芳香烃(Polycyclic aromatic hydrocarbons,PAHs)和碳烟的演化规律进行了试验研究.结果表明:在燃烧过程中,芘、苯并a]芘质量随曲轴转角呈单峰变化,萘、芴质量随曲轴转角呈"S"型变化趋势(先降低后升高再降低);碳烟的生成趋势与缸内温度呈较好的一致性,且碳烟与芘随曲轴转角具有相似的单峰状质量变化趋势,只是碳烟峰值出现的时刻稍有滞后.此外,正庚烷与柴油在柴油机中燃烧时生成的PAHs与碳烟具有相似的演化规律.

Histories of Polycyclic Aromatic Hydrocarbons and Soot During Combustion Process of Diesel Engine Fueled with N-Heptane and Diesel Fuel

Based on a novel total cylinder sampling system and gas chromatography-mass spectrometry(GC-MS)with programmed temperature vaporization and large volume injection(PTV),the histories of in-cylinder polycyclic aromatic hydrocarbons(PAHs)and soot during combustion process was investigated fueled with n-heptane and diesel fuel.Experimental results show that the mass of pyrene and benzo(a)pyrene give an unimodal variation trend versus the crank angle,while the mass of naphthalene and fluorene exhibits an S-shaped variation trend(decrease-increase-decrease)during combustion process.The trend of soot mass is in good agreement with cylinder temperature,and unimodal variation trend of soot mass.Similar to that of pyrene,soot attains its peak at a sligthly delayed crank angle compared to that of pyrene.Moreover,the histories of PAHs and soot for n-heptane is consistent with those of diesel fuel.