在一台共轨柴油机上,测量燃用氧化改质处理前后的生物柴油的排放污染物.通过气相-质谱联用仪,测量并分析改质前后油品组分变化.分析含氧燃料的热力NOx形成理论,提出了燃料化学结构决定柴油机排放污染物生成的观点.研究结果表明,生物柴油经氧化改质后,部分脂肪酸甲酯碳链中的双键被破坏,增加了环氧基或双羟基,含氧量和饱和度增加.改质处理抑制了生物柴油自身的氧化,避免了酸败和黏度增加.改质后生物柴油NOx和碳烟排放同时降低,改变了传统柴油机NOx和碳烟排放存在的互为消长关系.
The effects of bio-diesel on exhaust emission characteristics of DI diesel engine with high pressure common rail system were studied. Fuels used in the experiment were prepared by an additional oxidation upgrading and their fuel proper- ties were measured by GC/GS system. The Zeldovich NOx formation mechanism for biology oxygenated fuel was analyzed and a viewpoint was proposed that fuel structure was the most fundamental way to alter emission performance. The results showed that a number of double bonds of fatty acids were destroyed and replaced by epoxy group or double hydroxyl group. Larger weight proportion of oxygen and saturated carbon bonds were realized for bio-diesel improved by peroxidation up- grading. Anti-oxidation upgrading prevented oxidation of bio-diesel and kept it from getting rancid and viscose. After oxidation upgrading, NOx and smoke emission decreased and their "trade-off" tradition relationship was changed.