Estimation Model for Evaporative Emissions from the Nirco System of OVC-HEV

OVC-HEVs typically use the NIRCO systems to achieve their unique evaporative emission control strategies. This paper constructs the following OVC-HEV evaporative emissions calculation model: Based on the Clausis-Clapeyron equation and the ideal-gas equation, the pressure changes inside the sealed fuel tank and the evaporative emissions of fuel tank vapors are described; Then describe the adsorption and desorption equations of the carbon canisters through the results of the bench tests, and obtain its relationship with the initial working capacity and effective volume of the carbon canisters. Finally, based on the above sections, a NIRCO system evaporation emission calculation model for OVC-HEV is obtained, as well as a quantitative analysis of various influencing factors. Based on statistical data such as local climate temperature and driver usage, this model can be used to estimate the evaporative emissions of OVC-HEV fleets.