Performance and efficiency prediction of a hydrogen-oxygen engine for efficient hydrogen reconversion using a quasi-dimensional combustion model

This study investigates a 2-stroke hydrogen-oxygen-steam combustion process optimized for stationary hydrogen reconversion, i.e. converting stored hydrogen from electrolysis back into electricity. A quasi-dimensional combustion model incorporating gas dynamics, thermodynamics, wall heat transfer and a fractal-based combustion scheme was developed to simulate the full in-cylinder cycle. The model was validated against experimental data from a 4-stroke hydrogen engine to confirm its predictive capability. Parametric studies show that optimized valve timing, injection, and dilution yield 54 kW per 1.3 L cylinder and 54.6% indicated efficiency − 44% higher efficiency and 105% greater power density than a comparable 4-stroke engine.