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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.

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 diesel engine. Simulation results for in-cylinder soot volume fraction (SVF) have been compared to experimental data reported by Pires da Cruz et al., for the engine operating in low-temperature combustion (LTC) mode with high EGR, and for varied operating conditions. For the simulations, a 4-component surrogate blend containing n-hexadecane, heptamethylnonane, 1-methylnaphthalene, and decalin was used to represents the chemical and physical properties of the standard European diesel used in the engine tests. A validated detailed surrogate mechanism containing 392 species and 2579 reactions was employed to model the chemistry of fuel combustion and emissions.

While most published detailed reaction mechanisms for n-alkanes have been validated against shock-tube data that use pre-vaporized fuels, they have not been tested extensively using engine conditions. This is partly due to the complications of the effects of both spray and evaporation on ignition and on the gas-phase kinetics. In this study, CFD simulations of Ignition Quality Tests (IQT™) are used as a tool to validate the detailed reaction mechanisms, supplementing other validation tests that use more fundamental shock-tube data. The Ignition Quality Tester is a new ASTM standard for measuring the Cetane Number (CN) of fuels. Shock-tube data in the literature are limited for heavy n-alkanes of interest for engine fuels, which make CN data valuable for mechanism validation. The IQT employs a stationary combustion chamber that involves spray evaporation and mixing followed by combustion.