• 关键词：缸内直喷汽油机  多环芳烃  点火时刻  废气再循环  毒性当量

• 基金项目：国家科技支撑计划项目（No.2014BAG10B01）

• 滕升平
• 天津大学内燃机燃烧学国家重点实验室, 天津 300072

• 裴毅强
• 天津大学内燃机燃烧学国家重点实验室, 天津 300072

• 安彦召
• 天津大学内燃机燃烧学国家重点实验室, 天津 300072

• 王振平
• 重庆长安汽车股份有限公司动力研究院, 重庆 401120

• 聂相虹
• 重庆长安汽车股份有限公司动力研究院, 重庆 401120

• 季思思
• 重庆长安汽车股份有限公司动力研究院, 重庆 401120

• 摘要：在一台缸内直喷（GDI）汽油机上，分别用玻璃纤维滤膜和“聚氨基甲酸乙酯泡沫（PUF）+XAD-2”对尾气中的颗粒相和气相多环芳烃（PAHs）进行了采集，并用色谱-质谱联用仪（GC-MS）对PAHs进行了定性定量分析，研究了点火时刻和废气再循环（EGR）对PAHs排放的影响.结果表明：在缸内直喷汽油机尾气中，气相PAHs浓度远高于颗粒相PAHs浓度，在气相PAHs中主要是2环和3环等小环PAHs，而在颗粒相PAHs中则主要是4环及以上的大环PAHs.随着点火时刻的提前，尾气中PAHs总浓度呈现先减小后增加再减小的变化趋势，气相和颗粒相PAHs浓度也呈现相似的变化趋势.随着EGR率的增大，气相PAHs所占比例先减小后增大，颗粒相PAHs所占比例则先增大后减小，总PAHs的排放在整体上呈现逐渐减小的变化趋势.加入EGR后，GDI汽油机尾气的毒性显著增大.

• Abstract：The particulate-phase and vapour-phase polycyclic aromatic hydrocarbons (PAHs) were collected by a fiberglass filter and a "polyurethane foam (PUF)+XAD-2" respectively on an airflow guided gasoline direct injection (GDI) engine. The collected PAHs were analyzed by Gas Chromatography-Mass Spectrometer (GC-MS) quantitatively and the effects of spark timing and EGR rate on the PAHs emission were investigated in this study. The results showed that the concentration of vapour-phase PAHs, which was composed mainly by 2 and 3 rings PAHs, was much higher than that of particulate-phase PAHs composed by larger PAHs (4~6 rings). Concentration of total PAHs in exhaust first decreased slightly, and then increased and decreased finally with the advance of spark timing, and the concentrations of particulate-phase and vapour-phase PAHs also had the similar trends. With the increase of EGR rate, the percentage of vapour-phase PAHs first decreased and then increased, whereas the percentage of particulate-phase PAHs had opposite tendency. And the total emission of PAHs showed a decreasing trend in the overall. The exhaust toxicity of GDI engine increased significantly after addition of EGR.

• Key words：gasoline direction injection engine  polycyclic aromatic hydrocarbons  spark timing  exhaust gas recirculation  toxic equivalent

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