A 3-D simulation model including the inlet and the cylinder was built to study the backfire mechanism of PFI hydrogen internal combustion engines. A method controlling the backfire was put forward through optimizing the hydrogen injection angle. The low concentrated mixture gas was flow into the cylinder first after the intake valve opening, which can then lower the temperature of the exhaust gas and hot point inside the chamber. Based on the simulation model, the hydrogen injection angle influenced on the concentration and temperature of the mixture gas with the engine at different working speeds and conditions was investigated. The optimized hydrogen injection angle causing no backfire in all working conditions were found. It was proved by the experiment that the hydrogen internal combustion engine with the optimized hydrogen injection angle worked normally without backfire when the equivalent fuel air ratio of mixture gas reaching or even exceeding the stoichiometric fuel-air ratio within the speed range.%建立了包含进气道和气缸的氢内燃机三维仿真模型,研究了进气道燃料喷射氢内燃机不同转速和负荷条件下的回火机理.提出了通过优化喷氢相位,使低浓度混合气在进气门打开时首先进入气缸,降低缸内废气和热点温度,从而抑制回火的方法.仿真分析了不同转速和负荷条件下喷氢相位对进气门处混合气浓度和温度的影响,得到了最优的喷氢相位.经试验验证,优化的喷氢相位使氢内燃机能够在全工况内达到或超过混合气化学当量燃空比无回火工作.
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