The great influence on ecological-economic parameters of diesel engines is rendered with characteristics of used kinds of fuel, is especial their chemical compound. Traditional oil diesel fuel are a multicomponent mix in which as components enter the following groups of hydrocarbons:

• the saturated acyclic paraffins (alkans) С_n Н _2n+2 and acyclic naftens (cyclans) С _n Н _2n ;
• non-saturated (which contain double bonds) acyclic - olefins (alkens)С _n Н _2n and acyclic С _n Н _2n-2;
• aromatic hydrocarbons С _n Н _2n-6 [1];

       In conclusion necessary to say following: necessary clearly to present that, one deal distillation mixtures methyl ester (biofuel) under atmospheric pressure and maximum temperature of its boiling (~700К) when leaving beside 80% condensate MERO, and, quite other deal its evaporation and the following processes destruction molecules and their oxidations in condition of the camera of combustion of the diesel. In nominal state of working diesel 6ЧН12/14 pressures and the temperature in camera of combustion at the beginning initially and at the end injection fuel accordingly forms 6,9 MPA and 13,1 MPA; 940К and 1458К. However, knowledge of the chemical composition and quantitative correlation component in faction under investigation biofuels allows to value the intensity and fullness of its evaporation, create the identical mathematical model of the processes before-ignition preparation fuel before spontaneous combustion and its combustions.