Estimation of refueling emissions based on theoretical model and effects of E10 fuel on refueling and evaporative emissions from gasoline cars

Highlights: • Refueling emissions were measured using six cars and seven fuels. • Refueling emissions can be reproduced by a simple theoretical model. • The effects of E10 fuel on DBL emissions were measured. • Breakthrough of the canister in the DBL test appeared earlier with E10 than with E0. • The canister can store more E10 fuel than normal gasoline. The effects of Reid vapor pressure (RVP) on refueling emissions and the effects of ethanol 10% (E10) fuel on refueling and evaporative emissions were observed using six cars and seven fuels. The results indicated that refueling emissions can be reproduced by a simple theoretical model in which fuel vapor in the empty space in the tank is pushed out by the refueling process. In this model, the vapor pressures of fuels can be estimated by the Clausius–Clapeyron equation as a function of temperature. We also evaluated E10 fuel in terms of refueling and evaporative emissions, excluding the effect of contamination of ethanol in the canister. E10 fuel had no effect on the refueling emissions in cases without onboard refueling vapor recovery. E10 showed increased permeation emissions in evaporative emissions because of the high permeability of ethanol. And with E10 fuel, breakthrough emissions appeared earlier but broke through slower than normal fuel. Finally, canisters could store more fuel vapor with E10 fuel.