Hydrogen Two-Stroke Engine with Opposed Pistons: Balance Analysis as a Function of the Phase Angle Between the Two Crankshafts in the Case of a Six-Cylinder Configuration

The automotive sector is a major contributor to CO2 emissions, and hydrogen-fueled internal combustion engines offer a promising zero-carbon alternative. However, lean hydrogen combustion requires high air throughput and presents unique engineering challenges. This study investigated the dynamic balancing of a six-cylinder opposed-piston two-stroke hydrogen engine, analyzing different crankshaft configurations (60° and 120° crank throws), rotation directions (co-rotating versus counter-rotating), and phase angles. Results showed trade-offs between natural balancing, torque regularity, and gas scavenging efficiency. The optimal configuration depends on offset presence and crank phasing angle. The study provides a methodology and design guidelines for hydrogen and other alternative-fueled engines.