Experimental investigation of the performance of a two-stage charging system with an E-compressor and a VGT on a direct injection hydrogen engine

To further optimize the performance of H₂ICE while maintaining ultra-low NOx emissions, a high-performance air charging system is crucial. This study investigates the effects of an E-compressor and the combined impact of the E-compressor and a VGT on a 2.0L direct-injection H₂ICE. Compared to a single VGT, the E-compressor increases torque by 12.73%–135.5 Nm and reduces NOx emissions from 537 ppm to zero at 1000 rpm. At 3000 rpm, the torque increases by 2.2%, and NOx emissions drop by 50.9%. The E-compressor boosts the λ from 2.0 to 4.5, BTE from 33.73% to 34.38%, BD from 12.32°CA to 27.25°CA, and VE from 0.72 to 0.95 at 1000 rpm. These results highlight the effectiveness of the E-compressor in improving H₂ICE intake and combustion performance, particularly under low-speed conditions. The two-stage charging system significantly reduces NOx emissions, achieving reductions of up to 95.9% at 1500 rpm and 84.7% at 2000 rpm, while maintaining a balance between torque, emissions, and efficiency. The findings demonstrate that the E-compressor and VGT combination extends the H₂ICE's operating range, enabling higher performance and cleaner combustion under various conditions. This study provides valuable insights for developing high-performance H₂ICEs with minimal environmental impact.