Appointment of Optimum Fuel Injection Characteristics for a Direct Injection Spark Ignition Engine Using Numerical Simulation

Replacement of port fuel injection strategy with direct fuel injection to the combustion chamber is one of the effective methods for fuel consumption and emission reduction. With this strategy the engine would have diesel engines low fuel consumption. Also it would have gasoline engines power. Determination of optimum fuel injection angle in a direct fuel injection stratified charge engine is the object of this research. In this view Iranian nation engine first simulated numerically as port fuel injection using KIVA-3V code. Inlet port injection strategy was replaced with direct injection one hereinafter simulation results was calibrated using experimental data. Then optimum fuel injection was determined for direct injection stratified charge engine. Simulation results show that flow velocity vectors are biger because of fuel direct injection to the cylinder. Ninthy degree is the best fuel injection angle for determined engine condition. In this way air fuel is mixed better. With this fuel injection angle in cylinder pressure and cycle work increased in comparison to other fuel injection angles. Also, unburned hydrocarbons, carbon monoxide and nitrogen oxide emissions reduced in comparison to other fuel injection angles.