Three-stage autoignition of gasoline in an HCCI engine: An experimental and chemical kinetic modeling investigation
Three-stage autoignition of gasoline in an HCCI engine: An experimental and chemical kinetic modeling investigation
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DOI：
10.1016/j.combustflame.2008.04.022
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发表时间：
2008-12
影响因子：
4.4
通讯作者：
H. Machrafi;S. Cavadias
中科院分区：
文献类型：
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作者：
H. Machrafi;S. Cavadias
本文研究了汽油在HCCI发动机中的应用，分析了汽油在HCCI发动机中的自燃现象，并对汽油在HCCI发动机中的自燃机理进行了分析。已经使用的压缩比是13.5，保持入口温度在70 °C，当量比从0.3变化到0.54，并且EGR（由N2表示）比从0变化到37体积%。为了比较，使用PRF95和含有11体积%正庚烷、59体积%异辛烷和30体积%甲苯的替代物。一个先前验证的动力学替代机制被用来分析实验，并产生可能的解释动力学现象。从这项工作中，似乎很可能使用高辛烷值的汽油自燃的目的，即使在贫入口条件。此外，汽油及其替代物与PRF95不同，显示出三阶段自燃。由于PRF95不含甲苯，因此动力学机制表明，甲苯产生的苄基自由基导致这种所谓的“受阻预燃”，从而延迟汽油及其替代物的最终点火。支持这一解释的动力学机制的结果在本文中示出。
The alternative HCCI combustion mode presents a possible means for decreasing the pollution with respect to conventional gasoline or diesel engines, while maintaining the efficiency of a diesel engine or even increasing it. This paper investigates the possibility of using gasoline in an HCCI engine and analyzes the autoignition of gasoline in such an engine. The compression ratio that has been used is 13.5, keeping the inlet temperature at 70 °C, varying the equivalence ratio from 0.3 to 0.54, and the EGR (represented by N2) ratio from 0 to 37 vol%. For comparison, a PRF95 and a surrogate containing 11 vol% n-heptane, 59 vol% iso-octane, and 30 vol% toluene are used. A previously validated kinetic surrogate mechanism is used to analyze the experiments and to yield possible explanations to kinetic phenomena. From this work, it seems quite possible to use the high octane-rated gasoline for autoignition purposes, even under lean inlet conditions. Furthermore, it appeared that gasoline and its surrogate, unlike PRF95, show a three-stage autoignition. Since the PRF95 does not contain toluene, it is suggested by the kinetic mechanism that the benzyl radical, issued from toluene, causes this so-defined “obstructed preignition” and delaying thereby the final ignition for gasoline and its surrogate. The results of the kinetic mechanism supporting this explanation are shown in this paper.