Effect of Fuel Injection Timing on Graphitic Crystallite Size of Soot Particles from Diesel Engine

Abstract

Effect of fuel injection timing on graphitic crystallite size of soot particles from small DI diesel engine was investigated experimentally. The soot particles were sampled from exhaust gas, and its nanostructure was investigated by laser Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM). The soot Raman spectra showed that the graphitic crystallite size of soot obtained at rapid or late fuel injection timing was larger than that of fuel injection timing around 4 ～ 6deg. BTDC. In addition, the size of graphitic crystallite in the soot particles increases with increasing the engine load. These trends were strongly correlated with variation of the graphitic crystallite size obtained from analysis of HRTEM images.