Relative Importance of 22 Parameters to Evaporative Emissions — A Sensitivity Analysis of EVAP 2.0

A sensitivity analysis of EVAP 2.0, a vehicle evaporative emissions model, was performed to verify the operation of the model and to determine the relative importance of 22 parameters to the hot-soak and diurnal emissions of light-duty gasoline-powered vehicles. The response of the predicted emissions was determined for user input parameters and for internal functions within the model. In addition, three parameters which are not in the model were evaluated for their potential contribution to accurate emissions predictions.