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<p>To acquire the chemical occurrence mechanism of pre-ignition in marine natural-gas/diesel &amp; hydrogen/diesel engines, the auto-ignition and chemical reaction kinetic properties of methane/n-hexadecane and hydrogen/n-hexadecane mixtures under wide blending ratios and thermodynamic conditions were illuminated via shock tube system and LLNL C16 reaction mechanism. The findings indicated that replacing methane or hydrogen with micro n-hexadecane dramatically promoted the generation of active free radicals (H, OH) at initial accumulation stage and rapid reaction stage, which shortened the IDT (Ignition Delay Time) under most conditions. The decrease extent of IDT reduced when the n-hexadecane concentration increases. However, in the high-temperature reaction system of hydrogen/n-hexadecane mixture, when excessive n-hexadecane blended, the acceleration amplitude of start-up reaction induced by the increase in n-hexadecane concentration was insufficient to compensate for the inhibition amplitude of rapid reaction induced by the decrease in hydrogen concentration. Thus raising n-hexadecane concentration first shortened the IDT, then prolonged it. Further, raising the <i>ϕ</i> accelerated and suppressed the reaction progress under low and high temperatures. The ranks of contribution rates of various factors on the IDT of methane/n-hexadecane mixture were n-hexadecane content (40.95%) &gt; temperature (20.71%) &gt; pressure (19.94%) &gt; <i>ϕ</i> (18.50%). For hydrogen/n-hexadecane mixture, the influence degrees of four factors were very close. Therefore, at heavy engine operating load, the rich-oil-vapor/lean-natural-gas and lean-oil-vapor/lean-hydrogen zones were the most threatening locations in marine natural-gas/diesel engine and hydrogen/diesel engine. The results revealed the chemical reaction kinetics characteristics of low carbon renewable fuel/long carbon chain n-alkanes mixtures, which were helpful for providing potential suppression methods for the pre-ignition induced by cylinder oil in marine dual-fuel engines.</p>

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Mechanism of pre-ignition triggered by the auto-ignition of cylinder oil in marine hydrogen/diesel and natural gas/diesel engines. An application of the Taguchi method

  • 期刊论文

  • 发表日期：

    2026年5月6日

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  • Duode Qian,
  • Zhen Gong,
  • Yejian Qian

摘要

To acquire the chemical occurrence mechanism of pre-ignition in marine natural-gas/diesel & hydrogen/diesel engines, the auto-ignition and chemical reaction kinetic properties of methane/n-hexadecane and hydrogen/n-hexadecane mixtures under wide blending ratios and thermodynamic conditions were illuminated via shock tube system and LLNL C16 reaction mechanism. The findings indicated that replacing methane or hydrogen with micro n-hexadecane dramatically promoted the generation of active free radicals (H, OH) at initial accumulation stage and rapid reaction stage, which shortened the IDT (Ignition Delay Time) under most conditions. The decrease extent of IDT reduced when the n-hexadecane concentration increases. However, in the high-temperature reaction system of hydrogen/n-hexadecane mixture, when excessive n-hexadecane blended, the acceleration amplitude of start-up reaction induced by the increase in n-hexadecane concentration was insufficient to compensate for the inhibition amplitude of rapid reaction induced by the decrease in hydrogen concentration. Thus raising n-hexadecane concentration first shortened the IDT, then prolonged it. Further, raising the ϕ accelerated and suppressed the reaction progress under low and high temperatures. The ranks of contribution rates of various factors on the IDT of methane/n-hexadecane mixture were n-hexadecane content (40.95%) > temperature (20.71%) > pressure (19.94%) > ϕ (18.50%). For hydrogen/n-hexadecane mixture, the influence degrees of four factors were very close. Therefore, at heavy engine operating load, the rich-oil-vapor/lean-natural-gas and lean-oil-vapor/lean-hydrogen zones were the most threatening locations in marine natural-gas/diesel engine and hydrogen/diesel engine. The results revealed the chemical reaction kinetics characteristics of low carbon renewable fuel/long carbon chain n-alkanes mixtures, which were helpful for providing potential suppression methods for the pre-ignition induced by cylinder oil in marine dual-fuel engines.