为了探讨甲醇对汽油均质压燃( HCCI)燃烧和排放机理的影响,利用CHEMKIN软件从理论上研究了甲醇对汽油HCCI燃烧反应动力学机理的影响.结果表明:甲醇抑制了汽油(甲苯参比燃料)各组分的二次加氧过程,异辛烷基和正庚烷基继续脱氢,再氧化分解产生甲醛；甲苯基则直接氧化分解产生甲醛.随着甲醇体积分数增大,放热开始时刻提前,高温反应阶段的放热率峰值呈先增大后减小趋势.因此,可以通过调整反应中燃料的比例来控制着火时刻和放热峰值.CO和HC摩尔分数随甲醇比例增大逐步减小.随着燃空当量比升高,主燃烧峰值升高,主燃烧持续期延长,OH基生成速率和摩尔分数峰值增大,但放热开始时刻和OH开始生成时刻几乎不变.所以改变当量比可以改变燃烧反应中自由基摩尔分数和反应持续时间,但不能控制着火时刻.CO和HC摩尔分数峰值随当量比增大逐步增大,当量比过小时,大量CO和HC未被氧化.%The influence of methanol on the gasoline fuel HCCI ( homogeneous charge compression ignition) combustion and emission mechanism was investigated by CHEMKIN software. The results show that methanol inhibits the second oxygenation process for the components of gasoline. Isooctyl-alkyl and heptanes-alkyl keep on dehydrogenation, which are then oxidized to become formaldehyde. Tolyl is directly oxidized to be formaldehyde. As the proportion of methanol molar fraction increases, the start time of heat release is advanced, and the peak of heat release rate is increased firstly and then decreased in the high temperature phase. Thus, the ignition time and the peak of heat release can be controlled by adjusting the fuel ratio. CO and HC molar fraction decrease gradually with the increasing of methanol concentration. With the increasing of fuel air equivalence ratio, the main combustion peak increases, the main combustion duration extends, and the production rate and the peak of molar fraction for OH increase. But the start time of heat release and the generated time of OH are almost the same. So the free radical molar fraction in combustion reaction and the duration time can be changed by changing the equivalence ratio. But the ignition time cannot be controlled. The molar fraction peaks of CO and HC increase gradually with the increasing of equivalence ratio. If the equivalence ratio is too small, CO and HC cannot be consumed completely.
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