Numerical investigation and optimization of a novel guide tube hydrogen injection for a heavy-duty hydrogen engine using Taguchi method

Hydrogen internal combustion engines offer a promising pathway to low-carbon propulsion. For cost-effective port-fuel-injection hydrogen engines, intake hydrogen must be properly managed to improve in-cylinder mixing and minimize residual hydrogen to avoid backfire. This work evaluates a novel guide tube injector concept on a 5.1-L heavy-duty hydrogen engine. Three-dimensional simulations are performed to quantify the effects of guide tube geometry and injection timing on hydrogen transport, mixture formation, and residual hydrogen. The Taguchi design and TOPSIS are applied to assess factor influence and robustness. Results show that the guide tube significantly lowers residual hydrogen. The end of injection(EOI) should be no later than 90°CA before intake valve closing. Using the TOPSIS method, the effects of injection parameters on the optimization objectives are systematically evaluated, and the optimal combination is identified as a 20 mm guide tube length, a 10° guide tube angle, and an EOI of −277°CA.