A spectroscopy study of gasoline partially premixed compression ignition spark assisted combustion
A spectroscopy study of gasoline partially premixed compression ignition spark assisted combustion
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DOI：
10.1016/j.apenergy.2012.11.030
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发表时间：
2013-04
期刊：
影响因子：
11.2
通讯作者：
J. Pastor;J. M. García-Oliver;Antonio García;C. Micó;R. Durrett
中科院分区：
文献类型：
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作者：
J. Pastor;J. M. García-Oliver;Antonio García;C. Micó;R. Durrett
目前，许多研究工作都集中在研究和开发新的燃烧模式上，主要是基于使用局部稀薄的空气-燃料混合物。这种特性与废气再循环相结合，提供了低燃烧温度，减少了污染物的形成，提高了效率。然而，这些燃烧概念在燃烧相位控制方面存在一些必须克服的缺陷。这样，使用火花塞已被证明是一个很好的解决方案，以改善相控结合精益低温燃烧。它的性能在参考文献中有很好的报道，但是涉及燃烧过程的现象并没有完全描述。本工作的目的是通过紫外可见光谱法的应用，对火花辅助压缩点火模式进行详细的描述，以提高对燃烧过程的认识。利用宽带辐射成像和发射光谱法在光学发动机上进行了试验。发动机硬件是典型的压缩点火乘用车应用。由于汽油的反应性低，所以用作燃料。结合宽频带亮度图像、压力热释放率和紫外可见光谱，可以识别燃烧反应的不同阶段。火花放电后，第一个火焰核出现并开始生长为预混火焰锋，其特点是低而恒定的放热率，同时存在显著的OH自由基辐射。热量的释放增加了燃烧室内的温度和压力，这导致其余未燃烧的混合物自燃。第二阶段的特点是放出热量的速度更明显，反应通过燃烧室的传播速度更快。实测的紫外可见光谱与其他阶段相比也有一定的差异。不同燃烧自由基光谱的相对强度也与不同的燃烧相有关。
Nowadays many research efforts are focused on the study and development of new combustion modes, mainly based on the use of locally lean air–fuel mixtures. This characteristic, combined with exhaust gas recirculation, provides low combustion temperatures that reduces pollutant formation and increases efficiency. However these combustion concepts have some drawbacks, related to combustion phasing control, which must be overcome. In this way, the use of a spark plug has shown to be a good solution to improve phasing control in combination with lean low temperature combustion. Its performance is well reported on bibliography, however phenomena involving the combustion process are not completely described. The aim of the present work is to develop a detailed description of the spark assisted compression ignition mode by means of application of UV–Visible spectrometry, in order to improve insight on the combustion process. Tests have been performed in an optical engine by means of broadband radiation imaging and emission spectrometry. The engine hardware is typical of a compression ignition passenger car application. Gasoline was used as the fuel due to its low reactivity. Combining broadband luminosity images with pressure-derived heat-release rate and UV–Visible spectra, it was possible to identify different stages of the combustion reaction. After the spark discharge, a first flame kernel appears and starts growing as a premixed flame front, characterized by a low and constant heat-release rate in combination with the presence of remarkable OH radical radiation. Heat release increases temperature and pressure inside the combustion chamber, which causes the auto-ignition of the rest of the unburned mixture. This second stage is characterized by a more pronounced rate of heat release and a faster propagation of the reactions through the combustion chamber. Moreover, the measured UV–Visible spectra show some differences in comparison with the other stages. The relative intensities in of spectra from different combustion radicals have also been related to the different combustion phases.