Numerical and Experimental Investigations of Hydrogen Combustion for Heavy-Duty Applications

Reduction of the CO₂ greenhouse gas emissions is one major challenge the automotive industry as a part of the transportation sector is facing. Hydrogen is regarded as one of the key energy solutions for CO₂ reduction in the future transportation sector. First, a hydrogen-powered single-cylinder test rig for 2 liter heavy-duty engine will be introduced. Followed by a discussion of experimental results including variations of engine speed, torque, ignition strategy, air-fuel ratio, etc. In addition, the paper proposes a new phenomenological model for the prediction of hydrogen combustion. The model is based on the well-known two-zone Entrainment approach, supported by newly developed hydrogen-specific submodels for the calculation of the laminar flame speed and auto-ignition in the unburned mass zone. The developed physical-based combustion model is extensively validated based on the experimental single-cylinder results. Finally, the potentials and challenges as well as requirements on future hydrogen combustion systems are discussed based on full engine simulations and the experimental results. Further improvement potentials regarding combustion development and possible future exhaust after-treatment are be provided in the outlook.