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Approaches to the control of compression ignition through chemical-mechanistic investigation of low temperature oxidation process of hydrocarbons

通过碳氢化合物低温氧化过程的化学机械研究控制压缩点火的方法

基本信息

批准号：
15360106
负责人：
TEZAKI Atsumu
金额：
$ 7.74万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

1)A laser-spectroscopic system for elementary reaction level analysis of low temperature oxidation has been developed and applied to methoxymethyl + O2 reaction, which is the initial step of dimethyl ether oxidation. The system consists of near-IR multi-pass absorption optics for detection of HO2 and OH, UV absorption optics for detection of alkyl radical and alkyl peroxy radicals, and laser pulse photolysis to initiate the subject reaction. Time-resolved profiles of HO2, OH and methoxymethyl-peroxy radical were measured and compared to those calculated with kinetic models. Thermal decomposition of methoxymethyl radical was separately measured as the rate was a cause of uncertainty in the models. It was proposed in this study that methoxymethyl + O2 undergoes not only recombination to O2 adducts but also direct formation of OH + formaldehydes. The secondary reaction of OH + formaldehyde was confirmed to be the main route to HO2 formation, but another route through direct formation of H … More CO was also suggested.2)Chemical-mechanistic analyses of two-step autoignition process have been conducted in a single-cylinder piston engine. As the behaviors of transient species during the steps are crucial for the analysis, detection techniques for such species were developed and applied. (1)The time-resolved sampling technique through an electrically actuated valve was improved by adopting a direct mass-spectroscopic detection in a differentially pumped vacuum system. With a noble correction eliminating the contribution of initially sampled wall-boundary components, effective resolution of less than 1 ms was attained. It was confirmed that the transient species such as HCHO and H2O2 are formed in the first cool ignition stage and disappear in the final hot ignition. The amounts relative to the partial fuel consumption were also consistent with the recent model of dimethyl-ether oxidation. (2)The transient species of cool ignition were also measure in the exhaust within hot ignition suppressed conditions. Although the range of experimental conditions such as equivalence ratio is limited in this method, observable species is expanded and the accuracy are better by using mass spectrometer and FT-IR. The detection of formic acid and methyl formate in the cool ignition of dimethyl ether demonstrate the relative correctness of the 2000 version of Curran et al. detailed oxidation model compared to the 1998 version. Less

1)开发了低温氧化元素反应级分析激光光谱系统，并将其应用于二甲醚氧化的第一步甲氧基甲基+O2反应。该系统由用于检测 HO2 和 OH 的近红外多通道吸收光学器件、用于检测烷基自由基和烷基过氧自由基的紫外吸收光学器件以及用于引发目标反应的激光脉冲光解组成。测量了 HO2、OH 和甲氧基甲基过氧自由基的时间分辨曲线，并与动力学模型计算的曲线进行比较。甲氧基甲基自由基的热分解是单独测量的，因为该速率是模型中不确定性的一个原因。本研究提出，甲氧基甲基+O2不仅会重组为O2加合物，还会直接形成OH+甲醛。 OH+甲醛的二次反应被证实是形成HO2的主要途径，但也提出了另一种直接形成H…更多CO的途径。2)在单缸活塞发动机中进行了两步自燃过程的化学机械分析。由于瞬态物种在步骤中的行为对于分析至关重要，因此开发并应用了此类物种的检测技术。 (1)通过在差动泵真空系统中采用直接质谱检测，改进了通过电动阀的时间分辨采样技术。通过出色的校正消除了最初采样的壁边界分量的影响，获得了小于 1 ms 的有效分辨率。经证实，HCHO和H2O2等瞬态物质在第一个冷点火阶段形成，并在最后的热点火阶段消失。相对于部分燃料消耗的量也与最近的二甲醚氧化模型一致。 (2)在热点火抑制条件下还测量了排气中的冷点火瞬态组分。该方法虽然当量比等实验条件的范围受到限制，但通过质谱仪和傅立叶变换红外光谱仪的使用，扩大了可观测物种，且精度较高。在二甲醚冷点火中检测到甲酸和甲酸甲酯证明了 Curran 等人 2000 年版本的相对正确性。与 1998 年版本相比的详细氧化模型。较少的