The objective of this study is to investigate the effect of CO₂ mole fraction by simulated‐exhaust gas recirculation (EGR) on the simultaneous reduction of exhaust emission in CI engine, and to find the optimal operating conditions.For the better expression of the actual EGR, the different CO₂ mole fractions from 0% to 20% were applied for the simulated‐EGR. The CO₂ mole fraction by simulated‐EGR was changed in the initial air in steps of 5% from 0% to 20% in the cylinder. The N₂ mole fraction in the initial air was also changed according to the CO₂ mole fraction, and the O₂ mole fraction was fixed by 16.2% due to the same overall equivalence ratio.When the CO₂ mole fraction by simulated‐EGR increased by 5%, the peak cylinder pressure was decreased by about −1.5% and the indicated specific nitrogen oxide value was also reduced from −4.9% to −48.8% because the ignition delay was longer by the higher specific heat of CO₂ than N₂, it induced to suppress the rise of cylinder temperature. In addition, when the start of energizing timing was advanced until BTDC 23 deg, the ISSoot value was decreased because the proportion of premixed combustion was increased.

中文翻译：

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在早期燃烧条件下，通过在压燃式发动机中使用模拟排气再循环（CO2 + N2）来优化同时还原NO和烟尘的方法

这项研究的目的是研究模拟排气再循环（EGR）产生的CO ₂摩尔分数对同时降低CI发动机排气排放的影响，并找到最佳运行条件。 EGR，从0％到20％的不同CO ₂摩尔分数应用于模拟EGR。模拟EGR中的CO ₂摩尔分数在初始空气中从气缸中的0％更改为5％到20％。所述N个₂在初始空气摩尔分数根据CO也改变₂摩尔分数，和O ₂的摩尔分数是由16.2％的固定由于相同的整体等价ratio.When的CO ₂模拟EGR的摩尔分数增加了5％，峰值气缸压力降低了约-1.5％，指示的氮氧化物比值也从-4.9％降低至-48.8％，这是因为点火延迟因较高的比值而更长CO _2的热量比N _2的热量大，因此可以抑制气缸温度的升高。此外，当提前开始供气正时直到BTDC 23度时，ISSoot值会降低，因为预混燃烧的比例增加了。