Estimation model for evaporative emissions from gasoline vehicles based on thermodynamics

摘要

AbstractIn this study, we conducted seven-day diurnal breathing loss (DBL) tests on gasoline vehicles. We propose a model based on the theory of thermodynamics that can represent the experimental results of the current and previous studies. The experiments were performed using 14 physical parameters to determine the dependence of total emissions on temperature, fuel tank fill, and fuel vapor pressure. In most cases, total emissions after an apparent breakthrough were proportional to the difference between minimum and maximum environmental temperatures during the day, fuel tank empty space, and fuel vapor pressure. Volatile organic compounds (VOCs) were measured using a Gas Chromatography Mass Spectrometer and Flame Ionization Detector (GC-MS/FID) to determine the Ozone Formation Potential (OFP) of after-breakthrough gas emitted to the atmosphere. Using the experimental results, we constructed a thermodynamic model for estimating the amount of evaporative emissions after a fully saturated canister breakthrough occurred, and a comparison between the thermodynamic model and previous models was made. Finally, the total annual evaporative emissions and OFP in Japan were determined and compared by each model.Graphical AbstractDisplay OmittedHighlights•Government agencies require an after-canister breakthrough emission model.•Seven-day DBL tests were performed with Japanese vehicles under several conditions.•Composition analysis was performed to determine the emission compounds and OFP.•A new model for after-fully-saturated canister breakthrough is proposed.•The proposed model evaluates evaporative emissions precisely for Japanese vehicles.