Prediction of Uncontrolled Refueling Emissions from Gasoline Vehicles Based on Mathematical Models

The prediction of the uncontrolled refueling vapor generation of gasoline vehicles is the basis of the refueling emission control. It is of great significance to understand the mechanism of the gasoline vapor generation during the refueling process and to develop the refueling emission control devices. In this paper, the prediction of the refueling vapor generation of gasoline vehicles under uncontrolled conditions was conducted by using the empirical models, the steady state model and the time-varying diffusion model, respectively, and the prediction results were verified with the test results. The research results showed that the time-varying diffusion model had better adaptability and prediction accuracy than the empirical model. And the more influencing factors can be considered. But the verification and correction for this model were also needed by using experimental data. The empirical models had better prediction accuracy under specific conditions. However, due to the limitations of experimental conditions, the models lacked universality, which was an inherent defect of the empirical models. The steady-state model ignored the non-uniformity of fuel vapor concentration distribution in the fuel tank, resulting in a large error in the prediction results.