Based on the research work on the use of various alcohols as an alternative motor fuel for various internal combustion engines, a number of conclusions were drawn on the stages of formation of the main combustion products. This article presents a part of theoretical studies when using methyl alcohol in the form of a fuel emulsion as an alternative motor fuel. One of the most dangerous toxic components of liquid fuel combustion products is soot. Therefore, it is necessary to find ways to reduce its content. To do this, you need to know the methods and stages of soot formation, which affect the final concentration by weight. The most important task can be called the determination of the prevailing mechanisms of the appearance of soot in the combustion of liquid fuels in the cylinders of engines. A variable zonal model of soot formation in a 4 H 11.0 / 12.5 high-speed diesel engine is presented when working on an alternative emulsified alcohol fuel - methanol-fuel emulsion. The stages of the formation of carbon particles during the oxidation of fuel inside the cylinder are considered.