在Ricardo单缸4冲程发动机上利用GDI喷油器改装的缸内取样系统及2,4-二硝基苯肼(DNPH)衍生化法和高效液相色谱技术,研究了热废气状态下高辛烷值燃料甲醇和汽油均质压缩燃烧低温氧化过程中醛类物质的体积分数变化历程.结果表明,甲醇及汽油热废气中均含有一定量的甲醛、乙醛及微量的丙醛、丁醛和异戊醛.在压缩过程中,甲醛和乙醛体积分数均呈现先下降后增加的趋势,即在反应过程中先被消耗促进缸内燃料低温氧化反应的进行,随后在大量燃料被氧化过程中再次生成.由于甲醛反应机理历程的不同,相同负荷工况下甲醇热废气中的甲醛含量明显高于汽油燃料,是甲醇燃烧时刻早于汽油的原因之一.%With DNPH derivative method, high performance liquid chromatography (HPLC)technology and in-cylinder gas sampling system modified from a gasoline direct injection injector in a Ricardo Hydra 4-stroke single cylinder gasoline engine, the in-cylinder gas sampling experiments were conducted to study the aldehydes concentration histories during the low-temperature oxidation process of high-octane fuels (methanol and gasoline). Experimental results show that a certain of formaldehyde and acetalde- hyde, and a small amount of propionaldehyde, butyraldehyde and isovaleraldehyde are existed in the in- cylinder hot residual gas when fueled with methanol and gasoline. During the compression process, formaldehyde and acetaldehyde show a decreasing and then increasing trend, and this indicates that these substances are consumed through low-temperature reactions to promote the oxidation of fuel and then pro- duced during the main oxidation process of fuel. Under the same operation condition, formaldehyde con- centration in the residual gas of methanol is higher than that of gasoline because of different reaction mechanism. This may be one of the reasons that the ignition timing is earlier in compression combustion of methanol than gasoline.
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