Performance and emissions of passive pre-chamber injection ignition hydrogen engine under different hydrogen supply methods and load control strategies

Abstract

Hydrogen fuel is a zero-carbon energy source, and its clean combustion characteristics make it an ideal choice for achieving zero carbon emissions in the transportation sector. This study investigates a four-cylinder water-cooled hydrogen engine equipped with a passive pre-chamber (PPC). By integrating experimental and simulation methods, the research systematically examines the engine's combustion characteristics, power output, and emission performance across a wide range of excess air ratios (λ = 1.3–3.0). This work is conducted at 1600 rpm with a manifold absolute pressure of 70 kPa. An experimental comparison of combustion performance was conducted for hydrogen port injection (HPI) and hydrogen direct injection (HDI) fuel modes, providing a reference for the application of PPC in hydrogen engines. Results indicated that both the brake mean effective pressure (BMEP) and emissions decreased with increasing λ, while the brake thermal efficiency (BTE) reached its peak at λ = 1.4. A comparison of HPI and HDI performance under different manifold absolute pressure (MAP) conditions revealed that although the BTE of HDI was 0.79 % lower than that of HPI under full load (MAP = 100 kPa), HDI increased power output by 29.5 % and reduced NOx emissions by 41.4 %, demonstrating higher power, efficiency, and lower emissions. Therefore, HDI combined with the PPC scheme offers a promising approach for the practical application of hydrogen engines.