Based on the optical engine,the ignition characteristics,combustion process and soot emission characteristics of diesel under different 2-Methylfuran(MF) atmospheres were investigated by high-speed photography and in-...Based on the optical engine,the ignition characteristics,combustion process and soot emission characteristics of diesel under different 2-Methylfuran(MF) atmospheres were investigated by high-speed photography and in-cylinder combustion analysis technology.The results show that at the same main injection timing,the ignition time of reactivity controlled compression ignition(RCCI) combustion mode is earlier than pure diesel combustion,and the ignition point is concentrated near the nozzle.Diesel acts as a spark plug to ignite the mixture,but the flame develops slowly in the early stages and the pressure in the cylinder rises slowly.Compared with pure diesel,RCCI combustion model has smaller peak values of in-cylinder pressure and heat release rate,shorter ignition delay period,earlier combustion phase and shorter combustion duration.At main spray time at 6℃A BTDC and 12℃A BTDC,with the increase of MF premixing ratio from 0 to 0.75,the peak cylinder pressure decreased by 19.6% and 26% respectively.In addition,with the increase of the MF heat value ratio,the area of KL factor> 1.5 in the combustion chamber decreased and the space integral natural luminescence(SINL) peak value decreased by 48.37%,and the soot formation rate and yield decreased significantly.However,when the MF heat value ratio was too large(75% of the total calorific value),the ignition delay period increased,and misfire occurred at the main injection timing of 0℃A BTDC.The RCCI mode of MF/diesel dual fuel has better stability,and better control effect can be obtained at different main inj ection timing.展开更多
在总循环能量和发动机转速不变的条件下,运用一台六缸重型增压柴油机研究了不同喷油定时和氧含量对正丙醇/柴油活性控制压燃(Reactivity controlled compression ignition,RCCI)的燃烧与排放特性的影响.结果表明,随着喷油定时(Start of ...在总循环能量和发动机转速不变的条件下,运用一台六缸重型增压柴油机研究了不同喷油定时和氧含量对正丙醇/柴油活性控制压燃(Reactivity controlled compression ignition,RCCI)的燃烧与排放特性的影响.结果表明,随着喷油定时(Start of injection,SOI)的提前,第一燃烧阶段的放热率峰值和缸内温度不断增加,初始着火相位(CA10)和燃烧重心(CA50)同步提前,燃烧持续期基本不变,滞燃期增加.CO和HC的排放随SOI提前逐渐减小,而NO_(x)的排放随SOI提前逐渐增加;颗粒物排放的平均粒径(Particle average diameter,PAD)和颗粒物质量浓度(Particle mass concentration,PMC)及颗粒物数量浓度(Particle number concentration,PNC)会随SOI的提前呈现出逐渐降低的趋势.而氧含量(Oxygen ratios,RO)的增加会使缸内压力和缸内温度整体略微下降,滞燃期整体小幅度增加.CO和HC的排放会随着RO的增加而增加,但RO基本不影响NO_(x)的排放.另外,RO的增加会使得PAD增加,PNC降低,对PMC的影响规律不明显.展开更多
The present paper addresses the optimal heat release （HR） law in a single cylinder engine operated under reactivity controlled compression ignition （RCCl） combustion mode to minimise the indicated specific fuel co...The present paper addresses the optimal heat release （HR） law in a single cylinder engine operated under reactivity controlled compression ignition （RCCl） combustion mode to minimise the indicated specific fuel consumption （ISFC） subject to different constraints including pressure related limits （maximum cylinder pressure and maximum cylinder pressure gradient）. With this aim, a 0-dimensional （OD） engine combustion model has been identified with experimental data. Then, the optimal control problem of minimising the ISFC of the engine at different operating conditions of the engine operating map has been stated and analytically solved. To evaluate the method viability a data-driven model is developed to obtain the control actions （gasoline fraction） leading to the calculated optimal HR, more precisely to the optimal ratio between premixed and diffusive combustion. The experimental results obtained with such controls and the differences with the optimal HR are finally explained and discussed.展开更多
基金the financial support of the Key Scientific Research Projects of Colleges and Universities in Henan Province (No.21B470002)。
文摘Based on the optical engine,the ignition characteristics,combustion process and soot emission characteristics of diesel under different 2-Methylfuran(MF) atmospheres were investigated by high-speed photography and in-cylinder combustion analysis technology.The results show that at the same main injection timing,the ignition time of reactivity controlled compression ignition(RCCI) combustion mode is earlier than pure diesel combustion,and the ignition point is concentrated near the nozzle.Diesel acts as a spark plug to ignite the mixture,but the flame develops slowly in the early stages and the pressure in the cylinder rises slowly.Compared with pure diesel,RCCI combustion model has smaller peak values of in-cylinder pressure and heat release rate,shorter ignition delay period,earlier combustion phase and shorter combustion duration.At main spray time at 6℃A BTDC and 12℃A BTDC,with the increase of MF premixing ratio from 0 to 0.75,the peak cylinder pressure decreased by 19.6% and 26% respectively.In addition,with the increase of the MF heat value ratio,the area of KL factor> 1.5 in the combustion chamber decreased and the space integral natural luminescence(SINL) peak value decreased by 48.37%,and the soot formation rate and yield decreased significantly.However,when the MF heat value ratio was too large(75% of the total calorific value),the ignition delay period increased,and misfire occurred at the main injection timing of 0℃A BTDC.The RCCI mode of MF/diesel dual fuel has better stability,and better control effect can be obtained at different main inj ection timing.
文摘在总循环能量和发动机转速不变的条件下,运用一台六缸重型增压柴油机研究了不同喷油定时和氧含量对正丙醇/柴油活性控制压燃(Reactivity controlled compression ignition,RCCI)的燃烧与排放特性的影响.结果表明,随着喷油定时(Start of injection,SOI)的提前,第一燃烧阶段的放热率峰值和缸内温度不断增加,初始着火相位(CA10)和燃烧重心(CA50)同步提前,燃烧持续期基本不变,滞燃期增加.CO和HC的排放随SOI提前逐渐减小,而NO_(x)的排放随SOI提前逐渐增加;颗粒物排放的平均粒径(Particle average diameter,PAD)和颗粒物质量浓度(Particle mass concentration,PMC)及颗粒物数量浓度(Particle number concentration,PNC)会随SOI的提前呈现出逐渐降低的趋势.而氧含量(Oxygen ratios,RO)的增加会使缸内压力和缸内温度整体略微下降,滞燃期整体小幅度增加.CO和HC的排放会随着RO的增加而增加,但RO基本不影响NO_(x)的排放.另外,RO的增加会使得PAD增加,PNC降低,对PMC的影响规律不明显.
文摘The present paper addresses the optimal heat release （HR） law in a single cylinder engine operated under reactivity controlled compression ignition （RCCl） combustion mode to minimise the indicated specific fuel consumption （ISFC） subject to different constraints including pressure related limits （maximum cylinder pressure and maximum cylinder pressure gradient）. With this aim, a 0-dimensional （OD） engine combustion model has been identified with experimental data. Then, the optimal control problem of minimising the ISFC of the engine at different operating conditions of the engine operating map has been stated and analytically solved. To evaluate the method viability a data-driven model is developed to obtain the control actions （gasoline fraction） leading to the calculated optimal HR, more precisely to the optimal ratio between premixed and diffusive combustion. The experimental results obtained with such controls and the differences with the optimal HR are finally explained and discussed.
