LAUSR

ABSTRACT The authors studied hydrocarbon compositions of diesel fuel with a cetane improver and its relationship with the cetane number. The paper presents the results of these studies. The influence of synergistic and antagonistic effects in determining the cetane number of diesel fuels resulting from the interaction of various hydrocarbons (paraffins, naphthenes, aromatics) with the cetane improver is shown. These effects can be attributed to forces of intermolecular interaction of hydrocarbons with the additive, which influence the thermodynamic probability and the rate of formation of various hydrocarbon radicals during the combustion of the diesel fuel in engine conditions (t = 2000°C, p = 50 atm.). Energies of interaction of hydrocarbons with the cetane improver were estimated on the basis of quantum chemical calculations. Using the results of quantum chemical modeling, the authors developed a mathematical model to predict an increase in the cetane number of diesel fuels depending on the concentration of the additive for different fuel compositions, while taking into account intermolecular interactions of mixture components.