Simulation and Analysis of In-Cylinder Soot Formation in a Gasoline Direct-Injection Engine Using a Detailed Reaction Mechanism 2014-01-1135

3-D Computational Fluid Dynamics (CFD) simulations have been performed using a detailed reaction mechanism to capture the combustion and emissions behavior of an IFP Energies nouvelles optical gasoline direct injection engine. Simulation results for in-cylinder soot volume fraction have been compared to experimental data provided by Pires da Cruz et al. [1] The engine was operated at low-load and tests were performed with parametric variations of the operating conditions including fuel injection timing, inlet temperature, and addition of fuel in the intake port. Full cycle simulations were performed including intake and exhaust ports, valve and piston motion. A Cartesian mesh was generated using automatic mesh generation in the FORTÉ CFD software. For the simulations, a 7-component surrogate blend was used to represent the chemical and physical properties of the European gasoline used in the engine tests. A validated detailed combustion mechanism containing 230 species and 1740 reactions was employed to model the chemistry of the fuel surrogate combustion and emissions. A new seven step soot model coupled with the detailed combustion mechanism was used for soot predictions. Simulations captured the combustion phasing for all tests. Comparison of the calculated in-cylinder soot volume fractions at various crank angles to those measured shows good agreement. Simulations reproduced the observed location of soot in the cylinder, as well as trends reasonably well.