利用激光拉曼光谱对采集的柴油机四种工况下原机与低温等离子体(NTP)处理后的微粒(PM)样品进行定性。 依据五带模型对PM样品的拉曼光谱进行分峰拟合, 考察了D1 FWHM和D3相对强度R3的变化规律。 研究发现, 原机PM石墨结构有序性随柴油机负荷的增加而增强, 化学异相性减弱; NTP作用后, PM中石墨结构有序性及化学异相性较为稳定, 受发动机工况影响较弱, 同时样品中碳团簇含量增加。 利用化学动力学实验进一步研究PM碳结构演变和化学活性变化之间的关系, 有望使拉曼光谱技术成为柴油机PM快速定性的重要手段, 为PM的高效脱除提供依据。

Original and nonthermal plasma treated particulate matters(PM) samples of a diesel were obtained and characterized by Raman spectroscopy. A five-bands model was adopted for Raman spectrum curve fitting. As parameters involving most information about carbon structure, variation of FWHM of D1 band and D3 relative intensity were analyzed. It was found that original PM presented higher graphical structural order and lower chemical heterogeneity with the increase in the diesel load. After the treatment of NTP, the graphical structural order and chemical heterogeneity of PM kept at a relative stable level, affected very slightly by diesel load. Meanwhile, the amount of molecular carbon in PM increased. Further study for relation between structural evolution and chemical reactivity of PM with chemical kinetics would make Raman spectroscopy of great promise to become an important method for PM characterization, which could provide basis for more effective removal.