Study On Vehicle Fuel Evaporation Control Technologies Numerical Simulation On Flow Field Of Carbon Canister

With the development of auto industry and the improvement of People's living standard, the number of retained urban motor vehicles has risen sharply. The Environmental and Energy Problems arising therefore has been attached more and more importance. In recent years, with the sound and strict emission regulations, the vehicle's fuel evaporative emission control has become an important part of the vehicle emission control. The canister is the core component in vehicle fuel evaporative emission control system and plays a vital role in the performance of the whole system. The designer should consider the performance of the internal flow field as far as possible to flow more smoothly. Especially the pressure drop during adsorption and desorption process affect the performance of the carbon canister. Compared with traditional experimental method that consumes time and labor, numerical simulation could get the pressure speed, and streamline of the carbon canister's inter flow field, Analyze the performance of the internal flow field, avoid absorption region having excessive disturbance and vortex, Provide the basis for Performance Analysis and Design of the carbon canister, This will shorten the development period, enhance the work efficiency and reduce the cost.This paper is based on an engineering project and the flow field distribute law of an carbon canister is analyzed by modeling and calculating, Analysis of the distribution of flow field and compared with test results, analysis of the performance of the internal flow field of the carbon canister.Firstly, introduces the present development of numerical simulation technology, vehicle fuel evaporation mechanism of pollutants, the control method of vehicle evaporative emissions, vehicle fuel evaporative emission control systems theory, outlines computational fluid dynamics (CFD) of the basic theory. This paper introduces the basic theory of porous media model. According to Darcy's law and the Ergun equation using the hydraulic radius model, and combined with the basic equation of fluid dynamics, get the formula of viscous resistance and inertial resistance of the porous media in Fluent. Application Fluent computational fluid dynamics software to simulate a vehicle canister internal flow field, to obtain the pressure field, velocity field, and the streamline, Analysis of the distribution of flow field and compared with test results, and prove that porous medium can simulate the internal structure of toner region and verify the correctness of Fluent. The results show that, the PSID between adsorption orifice and atmospheric orifice of the two absorption processes were 0.3kPa and 0.8kPa; the PSID between desorption orifice and atmospheric orifice of the two Desorption conditions were 1.1kPa and 2.3kPa, and the pressure drop of adsorption orifice were 3mbar and 6mbar.The numerical simulation results of the four processes are accordant with the experimental data, and the results meet the demand of the pressure drop.After prove that porous medium can simulate the internal structure of toner region and verify the correctness of Fluent, application Fluent computational fluid dynamics software to simulate a a carbon canister's internal the flow field of a motorcycle, get it's pressure, speed, and streamline distribution, analyze the performance of flow field, and the results meet the demand of the pressure drop.