The thermodynamic system “fuel tank of a vehicle” energy model. Processes of unsteady heat transfer at constant fuel mass

Abstract

Introduction . Along with the toxic substances formed during the combustion of fuel in the engine, a certain amount of hydrocarbons is emitted by a vehicle into the atmosphere in the form of fuel vapors evaporated from the fuel tank and fuel system components. The energy balance in the fuel tank determines the overall level and change in fuel temperature. The higher their values, the more vapors are formed in the fuel tank, which increases the load on the fuel vapor recovery system. The purpose of the study was to develop an energy model of a vehicle fuel tank describing the non-stationary heat transfer processes for steadily operating modes; formulate criteria for the fuel tank energy efficiency depending on the formation of fuel vapors. Methodology and research methods . The analysis of heat fluxes supplied to and removed from the fuel tank has been carried out. As a result of solving the energy balance equation the thermal properties parameters of the fuel tank were obtained. Scientific novelty and results . The change in the temperature of the fuel in the tank has been substantiated in accordance to the time determined by the exponential law. Complex parameters were proposed, the main of which were: equilibrium temperature head, time constant, maximum of temperature speed and heat flux supplied to the fuel, as well as the value of the temperature head flux developed during one hour of idling - hourly fuel consumption. Practical significance . The results of six variants of “UMP” family sedan cars testing, differing in characteristic parameters of fuel tanks and fuel modules, have been presented. It is shown that the implementation of gasoline pumps frequency control can reduce fuel heating by 30%.