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arXiv · 1810.10701

Raman Spectroscopy of Diesel and Gasoline Engine-Out Soot Using Different Laser Power

Haiwen Ge·Zhipeng Ye·Rui He
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Abstract

We studied engine-out soot samples collected from a heavy-duty direct-injection diesel engine and a port-fuel injection gasoline spark-ignition engine. The two types of soot samples were characterized using Raman spectroscopy with different laser power. A Matlab program using least-square-method with trust-region-reflective algorithm was developed for curve fitting. We used a DOE (design of experiments) method to avoid local convergence. This method was used for two-band fitting and three-band fitting. The fitting results were used to determine the intensity ratio of D and G Raman bands. We find that high laser power may cause oxidation of soot samples, which gives higher D/G intensity ratio. Diesel soot has consistently higher amorphous/graphitic carbon ratio and thus higher oxidation reactivity, in comparison to gasoline soot, which is revealed by the higher D/G intensity ratio in Raman spectra measured under the same laser power.

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Haiwen Ge, Zhipeng Ye, Rui He. 2018-10-25. Raman Spectroscopy of Diesel and Gasoline Engine-Out Soot Using Different Laser Power. https://arxiv.org/abs/1810.10701

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