A study on the effect of spark plug micro-hole hydrogen injection on the spray and combustion processes of a gasoline engine with intake port water injection

Yuan Zhuang, Zhihong Lin, Rui Zhai, Yuhan Huang, Binjian Nie and Yihan Li

Energy, 2025, vol. 315, issue C

Abstract: This study examined the impact of hydrogen direct injected through an aperture on edge of the spark plug (SHDI) on the spray and combustion processes of a gasoline engine operating with high water injection rates. The results demonstrated that SHDI effectively mitigated the negative effects of water injection, enhancing the combustion process. SHDI-generated jets significantly increased in-cylinder turbulence—by up to 40 m2/s2—and redirected large-scale vortex motion, enriching the fuel mixture around the spark plug. The equivalence ratio near the spark plug rose from 0.5 to 0.8, promoting the formation of a stable flame kernel up to 7° crank angle (CA) earlier, which accelerated overall combustion. Additionally, the heightened turbulence and increased in-cylinder temperatures induced by SHDI reduced water droplet size, promoting faster evaporation and minimizing the flame-extinguishing effects of residual water mist under high-load, high-water injection conditions. This also leaded to a more uniform air-fuel ratio distribution. Furthermore, hydrogen injection generates abundant H radicals, which enhance the formation of reactive species, accelerating low-temperature fuel decomposition and flame propagation. This counteracts the dilution effect of water injection, ensuring stable and efficient combustion even in challenging conditions. When the hydrogen injection ratio is 15 %, carbon emissions are reduced by 16 %.

Keywords: Hydrogen addition; Port water injection; Combustion; Gasoline engine (search for similar items in EconPapers)
Date: 2025
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Persistent link: https://EconPapers.repec.org/RePEc:eee:energy:v:315:y:2025:i:c:s0360544225000088

DOI: 10.1016/j.energy.2025.134366

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