Computer Simulation of a Flex-Fuel Engine Running on Different Gasoline-Hydrous Ethanol Blends

Nowadays computer simulation is an important tool to support new internal combustion engine projects, but still further studies are necessary for its use in fuel development. In order to study the influence of fuel properties on engine combustion and emission performance, a computer model was designed based on a Flex-Fuel engine geometric data. Model was validated with experimental tests done on an engine dynamometer. A simulation software was used to simulate the experimental conditions, by using Wiebe two zone combustion and Woschni heat transfer models. In-cylinder maximum pressure, IMEP and emission data were calculated for different gasoline-hydrous ethanol blends at 3875 rpm, 60 Nm and 105 Nm. Total hydrocarbons concentration was simulated comparing the experimental data of hydrocarbons added with unburned ethanol emission measured with a FTIR analyzer. The computer model presented good agreement with experimental data for maximum in-cylinder pressure, intake air, fuel_consumption and IMEP. Regarding emissions, the simulations could not match experimental data without specific adjustment for each fuel, showing the need for further modeling development.