Modeling and influence factors analysis of refueling emissions for plug-in hybrid electric vehicles

Abstract Vehicle fuel evaporative emissions are an important source of volatile organic compounds (VOCs), causing serious pollution to the environment. Plug-in hybrid electric vehicles (PHEVs) often use high-pressure fuel tank to seal the fuel vapor generated by running loss (RL), hot soak loss (HSL) and diurnal breathing loss (DBL) in the fuel tank, resulting in increased refueling emissions. With the widespread use of PHEVs, the issue of refueling emissions cannot be ignored. In this study, according to the working characteristics of PHEV, the refueling process is divided into depressurization phase and refueling phase, and a mathematical model is established for the fuel vapor emission process. The mathematical model is solved and calculated by using MATLAB, and compared with the experimental results. The error between experimental and calculated results of refueling emissions is only 2.45%, indicating that the established mathematical model can accurately predict the refueling emissions of PHEVs. The refueling emission experiment activities is carried out, and the influencing factors of PHEV refueling emission are discussed, including initial pressure, ambient temperature and refueling temperature. The effect of the temperature difference between ambient temperature and refueling temperature on refueling emissions is discussed for the first time, and it is found that refueling temperature has a more significant impact on refueling emissions compared with ambient temperature. When refueling temperature increases to 303 K and 313 K compared to 293 K, refueling emission mass increases by 31.97% and 69.88% respectively.