A novel turbocharging matching method for hydrogen engines and experimental validation to achieve high power performance

Conventional turbocharger matching struggles with hydrogen engines due to the unique features, including high intake mass flow demand, low turbine-inlet temperature, and significant backpressure sensitivity. These challenges complicate the pursuit of high power density and low NOx emissions. This study introduces a novel two-sided matching method for hydrogen engines. On the compressor side, a target λ predicts intake mass flow and pressure ratio for preliminary selection. On the turbine side, regression analysis provides accurate temperature estimates with R² = 0.928, and functional relationships between engine output and turbine efficiency with the mass flow ratio through the turbine are captured. Experimental results define operational boundaries of the expansion ratio from combustion risks and the high pumping loss due to backpressure. Following validation of the proposed method and subsequent turbocharger optimization, a 2.0L direct-injected (DI) hydrogen engine achieves stable high-power output without abnormal combustion. Equipped with a turbocharger featuring a maximum turbine reduced mass flow of 0.0151 kg/s·K^0.5/kPa, the engine reaches a peak power of 140.1 kW @ 4800 rpm and a peak torque of 322.8 N·m @ 2500 rpm. This work provides an effective method for selecting turbochargers, supporting the development of high-power-density hydrogen engines.