米姗,王浒,李彩云,尧命发.直喷汽油对反应活性控制压燃负荷拓展影响的数值模拟研究[J].内燃机工程,2019,40(2):97-103.
直喷汽油对反应活性控制压燃负荷拓展影响的数值模拟研究
Numerical Simulation Study of the Effect of Gasoline Direct Injection on the Load Expansion of Reactivity Controlled Compression Ignition Combustion Mode
DOI：10.13949/j.cnki.nrjgc.2019.02.014
关键词:双燃料  反应活性控制压燃  喷油策略  分层燃烧  负荷拓展  排放
Key Words:dual fuel  reactivity controlld compression ignition(RCCI)  injection strategy  stratified combustion  load extension  emissions
基金项目:国家自然科学基金项目(51506145)
作者单位
米姗,王浒,李彩云,尧命发 天津大学 内燃机燃烧学国家重点实验室，天津 300072 
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摘要:基于三维计算流体力学软件CONVERGE，通过数值模拟的方法，基于不同的燃油总量、直喷汽油量、预混汽油油量和汽柴油喷射时刻等参数，展开了缸内直喷汽油对反应活性控制压燃（RCCI）燃烧模式高负荷拓展影响的研究。结果表明：进气压力及柴油喷射时刻会影响缸内浓度分层进而影响燃烧过程，而汽油喷射时刻影响不明显；在汽油采用进气道结合缸内直喷的混合喷射策略下，增加缸内直喷汽油量可以进一步增强缸内的混合气浓度分层，延长燃烧持续期，降低缸内的最高燃烧压力和压力升高率，实现更低的燃烧温度。仿真计算结果显示：若保证碳烟和NOx排放在限值内且油耗有所降低，可将平均有效指示压力（IMEP）拓展至1.6 MPa；将IMEP拓展到1.7 MPa后，增加汽油的预混比例并不能提高IMEP，但对排放略有改善，相应的压力升高率和燃烧压力提高。
Abstract:Based on the application of 3-dimensional computational fluid dynamics software CONVERGE, a numerical simulation study of the effect of gasoline direct injection on the high load expansion of reactivity controlled compression ignition(RCCI) combustion mode was carried out under different injection parameters, including total fuel flow, direct-injected gasoline flow, premixed gasoline flow and gasoline/diesel injection timing. Results show that the intake pressure and diesel injection timing affect the concentration stratification in the cylinder, and then affect the combustion process, while the effect of gasoline using port injection and in-cylinder direct injection, increasing the amount of direct injected gasoline in the cylinder can further enhance the concentration stratification of the in-cylinder mixture, and prolong the combustion duration to reduce the in-cylinder peak pressure and pressure rise rate, resulting in a lower combustion temperature. The simulation calculations also show that if the soot and NOx emissions are kept within the emission limits, the IMEP can be increased to 1.6 MPa, but when the IMEP reaches 1.7 MPa, increasing the gasoline premixed ratio does not increase the IMEP, but slightly improve the emissions while responding to increased pressure rise rate and peak pressure.
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