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The use of green hydrogen as a fuel for internal combustion engines is a cleaner alternative to conventional fuels for the automotive industry. Hydrogen combustion produces only water vapor and nitrogen oxides, which can be avoided with ultra-lean operation, thus, eliminating carbon emissions, from a tank-to-wheel perspective. In this context, the aim of this study is to investigate the influence of hydrogen injection timing and duration on the homogeneity of the hydrogen-air mixtures. Computational fluid dynamic (CFD) simulations were performed to analyze the distribution of air-fuel ratios along the engine's combustion chamber. The simulation software was CONVERGE 3.0, which offers the advantage of automatic mesh generation, reducing the modeling efforts to adjusting the operating conditions of the studied case. Before comparing the injection parameters, a mesh independence test was conducted along with model validation using experimental data.

In order to further explore the potential of hydrogen as an alternative fuel, this study aims to validate a computational fluid dynamics model for hydrogen combustion in a port fuel injection spark ignition engine. The engine operates at 1800 rpm with a compression ratio of 10:1, under two lean combustion conditions: excess air ratios of 2.5 and 1.7, at full and part load, respectively. The simulations were performed using the CONVERGE 3.1 software and the C3MechV3.3 reaction mechanism. The predictions were then compared with experimental data to assess the accuracy and validity of the model, enabling the comparison of different lean operating conditions to evaluate important combustion characteristics, such as flame development, apparent heat release and NOx formation. The tested model successfully validated the two experimental conditions, accurately adjusting the in-cylinder pressure profiles for both cases of lean hydrogen mixture combustion.