Description of a Motor Vehicle Evaporative Emissions Model-EVAP 2.0

A computer model that predicts fleet diurnal and hot-soak evaporative emissions is discussed. The model calculates hourly and daily emissions for a fleet of light-duty gasoline-powered vehicles with real-world driving patterns. The effects of fuel volatility, ambient temperature, fuel weathering, fuel tank level, refueling characteristics, driving pattern, fleet characteristics, calendar year, and fuel tank heating and cooling are quantified. Each relationship is based on data collected in government and industry studies.