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Introduction (statement of the problem and relevance). While gasoline-powered vehicles generate a significant amount of hydrocarbons in the form of the fuel system emitted vapors, the main element of the system being the fuel tank, modern requirements for evaporative emission limits are significantly tightened. At the same time, the vaporization process parameters and the fuel vapor amount are determined by the dynamics of fuel heating in the tank under various modes of vehicle operation.The purpose of the research was to develop a “vehicle fuel tank” energy model, seeking to create an open thermodynamic system which can exchange matter and energy with the environment depending on the variable amount of fuel in the tank.Methodology and research methods. The analysis of heat flush connected to the fuel tank and taken away from it was being carried out. As a result of solving equations for open and closed thermodynamic systems, the parameters characterizing the thermal properties of the fuel tank were obtained.Scientific novelty and results. Additional complex parameters have been proposed, the main of which are: heat transfer of the tank; tank heat capacity; supplied heat flux; the rate of heat capacity change; tank emptying time; fuel heating acceleration factor; the maximum rate of change in temperature difference. To assess the heat and power properties of the fuel tank, an additional parameter of the sphere surface area ratio to the surface area of the same volume tank has been proposed, which allowed estimating the fuel tank heat transfer to the environment.Practical significance. Equations have been obtained that allow estimating the level of fuel temperature depending on the thermal properties and shape of the fuel tank in the absence and presence of fuel pump control.

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Introduction (statement of the problem and parameters relevance). The composition of the mixture of air and gasoline vapors differs in air and vapors ratio when purging the absorber at different time of the car operation. Therefore, the air-fuel mixture entering the engine for afterburning can create uncertainties in lambda control.The purpose of the research was to determine the main features of lambda regulation in an unstable fuel-air mixture.Methodology and research methods. An analysis of the mixed air and fuel vapor flows entering the engine during absorber purge was made. The composition and quantity effect of this mixture on the excess air coefficient was determined. The main parameters of air and gasoline vapor mixture in the fuel tank vapor space were established.Scientific novelty and results. An equation obtained testifies that the excess air coefficients in the flows of the fuel-air mixture relate to the mixture flow rate during absorber purge. The requirements for the composition of the fuel-air mixture leaving the absorber have been formulated. In order not to exceed these values the threshold values of short-term fuel supply were corrected and the relative mass flow value rate of gasoline vapors from the tank in relation to the air flow rate purge was determined.Practical significance. The factors limiting the flow sections of the absorber gas-air paths and the optimal ratios of the flow sections were determined on the example of a two-chamber absorber to exclude excessive enrichment of the fuel-air mixture entering the engine during purge.

Hydrocarbon emissions from fuel evaporation contribute significantly to the total emissions of harmful substances from vehicles with forced spark ignition. To meet the legally established standards for limiting hydrocarbon emissions from evaporation, all current vehicles use fuel vapor control systems. The design of the system can vary and depends on the sales market of a particular vehicle. This article describes the development of this system for the market of the Russian Federation, as well as optimization for promising sales markets with more stringent environmental requirements.