Modeling of Hydrogen Combustion and NOx Formation for an Effective 3D-CFD Virtual Engine Development

Hydrogen-powered internal combustion engines are emerging as a promising pathway toward climate-neutral mobility, as they combine the potential for high efficiency with zero direct CO2 emissions. At the same time, the unique combustion characteristics of hydrogen introduce new challenges, including auto-ignition, flame development and NOx emissions, particularly under lean operating conditions. This book presents an advanced 3D-CFD framework for the virtual development of hydrogen combustion engines. By combining detailed chemical kinetics with computationally efficient look-up table methods, predictive models for self-ignition, turbulent flame propagation and thermal NOx formation during H2 combustion have been developed and validated. The proposed approach enables systematic virtual engine studies that go beyond the limits of experimental testing, while keeping the computational effort within a practical range. When applied to a single-cylinder hydrogen research engine, the framework provides detailed insights into the processes occurring within the cylinder and supports the optimization of combustion strategies, with the aim of improving efficiency and reducing emissions.