Physics-Based Simulation for Sustainable Fuels Part 1: Simulation-Driven Hydrogen Engine Power Cylinder Unit Optimization and Experimental Confirmation

The demand for sustainable mobility and transportation is accelerating the adoption of alternative fuels, particularly hydrogen, in internal combustion engines. However, these engines present specific risks, such as explosive crankcase gas accumulation from blow-by and irregular combustion resulting from oil transport into the combustion chamber. Addressing these challenges requires advanced simulation tools to optimize power-cylinder-unit performance, specifically piston ring and gas dynamics. This study demonstrates simulation capabilities validated through detailed comparisons of measured and simulated inter-ring pressures across light vehicle, heavy-duty, large-bore, and motorsport applications, spanning a broad range of engine sizes covering displacements from 2 to 96 liters. Inter-ring pressure obtained via inhouse telemetry measurements within the power cylinder unit provided crank-angle resolved data throughout the ring pack, serving to validate 2D and 3D ring and gas dynamics simulation models. The simulation approach incorporates detailed modeling of piston, ring, liner, and lubricant characteristics under actual operating conditions, achieving agreement with measurement data within 2% deviation within the operation map. The validated models accurately predict hydrogen migration to the crankcase and gas-flow-driven oil ingress into the combustion chamber, enabling optimized PCU designs with a 30% reduction in blow-by and elimination of reverse-flow-driven oil transport. Comparative analysis shows that 2D simulations can achieve accuracy equivalent to 3D models with significantly reduced computational effort. This validation confirms MAHLE as a leading development and technology partner for internal combustion engine development for sustainable mobility and transportation.