| The soot formation in diesel engine's burning not only badly pollutes the environment, but also brings harm to human's health. Researching the soot formation and oxidation has become one of important and hot question about the emission controlling of the diesel engines. The computer numerical simulation costs less time and capital and can realize the visualization of analyses.In this paper, the Moss model for soot formation programmed by C language were integrated into the commercial CFD-code Fluent to construct a multidimensional and unsteady mode and to simulate the process of soot formation and oxidation in diesel engine's burning process.The simulation of the paper is divided into two parts. In the first part, it simulates and analyses the process of soot formation and oxidation. The paper displayed the trend of gas average temperature, pressure, number density and volume fraction of soot, and soot particles average diameter evolution with crank angle in cylinder. The calculated soot mass is lower than the tested, but it consists with tested results in the trend of formation and oxidation of soot. The analyzed to the soot formation contours and evolution trend provide guidance to the next simulation.In the second part, the simulation of the effect of injection timing, engine speed, intake temperature and load on number density and volume fraction of soot is performed. And it analyses the mechanism of the formation of soot using the contours of the temperature in cylinder and the oxygen's concentration. The result show that, under the same condition:the diesel engine has a best injection timing which makes the emission of soot least. The number density of soot is increased by the engine speed. But there is a best speed that makes the volume fraction of soot least. The number density and volume fraction of soot are increased by the intake temperature. The formation mass of soot is increased by the loading, but the oxidation mass of soot is lower under low loading.
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