【摘要】 为提高内燃机热效率和降低污染物排放，研究了CO₂稀释条件下的甲烷微波辅助点火特性。基于定容燃烧弹台架，将微波馈入到对置式电极以促进点火，采用高速纹影法探索不同试验条件下火核早期发展规律。结果表明：微波辅助点火（MAI）模式下，CO₂稀释极限得到提高，16%CO₂稀释比仍能成功点火。在8%CO₂稀释比时，馈入微波能将甲烷可燃极限从火花点火（SI）模式下的0.7拓展到0.6。随微波功率的升高，火核等效半径增大，但增大程度逐步减小；在不同CO₂稀释比条件下，微波频率对火核的增强效果出现不同规律。本研究结果可为废气再循环（EGR）氛围下应用微波辅助点火技术提供理论支撑。更多还原

【Abstract】 This paper investigated the characteristics of microwave-assisted ignition of methane under CO₂ dilution conditions to improve the thermal efficiency of internal combustion engines and reduce the emission of pollutants. Explored that microwave was fed to the opposed electrodes to promote ignition, and the development law of early flame core under different test conditions by using high-speed schlieren method based on a constant volume combustible bomb platform. The results show that in Microwave Assisted Ignition（MAI） mode,the CO₂ dilution limit is improved, and the 16% CO₂ dilution ratio can still be successfully ignited. Under the condition of 8% CO₂ dilution ratio, feeding microwave energy expands the methane ignition limit from 0.7 in the Spark Ignition（SI） mode to 0.6. With the increase of microwave power, the equivalent radius of flame core increases, but the degree of increase gradually decreases, the enhancement effect of microwave frequency on the flame core under different CO₂ dilution ratios is different. These results can provide theoretical support for the application of microwave assisted ignition technology under Exhaust Gas Recirculation（EGR） atmosphere.更多还原