Computational modeling, validation, and utilization for predicting the performance, combustion and emission characteristics of hydrogen IC engines

Hydrogen-fueled internal combustion engines are considered to be more efficient and cleaner alternatives to their fossil-fueled counterparts. Reasonably fast and accurate predictive computational tools are essential for practical design, control and optimization of hydrogen engines. To serve for this broader purpose, a computational model, which has been widely used for gasoline and diesel engines, is investigated for its capability to simulate hydrogen engines. Specifically, fuel-specific sub-models are first incorporated by properly accounting for hydrogen’s distinct properties such as flame speed and burn rate. The accuracy of the model is then assessed by validating it in comparison to independent experimental data. Finally, it is utilized to quantify the environmental impact of exhaust gas recirculation. With these improvements, the present predictive model is shown to capture the measured engine performance and emission data well under different operating conditions. In particular, the variations of peak in-cylinder pressure, heat release rate, brake power, brake thermal efficiency, exhaust temperature, and NOx emissions are predicted close to the measured values. With the addition of a proportional-integral-derivative controller to the engine model, exhaust gas recirculation level is varied, resulting in nearly an order of magnitude reduction in NOx emissions during the present simulations.