摘要
在总循环能量与乙醇能量替代比不变的条件下,研究了不同柴油喷油定时(start of injection, SOI)下乙醇/柴油活性控制压燃(reactivity controlled compression ignition, RCCI)六缸增压柴油机低负荷的燃烧与排放特性。结果表明,随着SOI的提前,RCCI冷焰反应相位提前,高温放热的瞬时放热率峰值先增大后减小,滞燃期逐渐增大,缸内燃烧温度逐渐增加,燃烧重心先提前后推迟。传统燃烧模式(conventional combustion mode, CCM)与RCCI的燃烧特性差异随着SOI的提前而增大。与CCM相比,RCCI的NOx排放的减少量随着SOI的提前而增加,HC与CO排放的增加量随着SOI的提前而减少。随着SOI的提前,粗态(>273.8～1 000nm)颗粒物质量分数从84.09%减小到32.87%。聚集态(>13.3～273.8 nm)颗粒物质量分数从15.88%增加到66.36%。与CCM相比,RCCI的颗粒物排放的数量浓度较少,尤其是核态颗粒物;但RCCI颗粒物排放质量浓度较高。
Reactivity controlled compression ignition(RCCI)has great potential for improving thermal efficiency and reducing pollutant emissions.RCCI can also control the combustion phase and suppress the maximum pressure rise rate.The RCCI is characterized by the in-cylinder reactivity stratification,which is formed by directly injecting the high reactivity fuel into the low-active homogeneous gas mixture in the cylinder.Based on a heavy-duty six-cylinder turbocharged diesel engine,in this paper,the influence of different start of injection(SOI)timings of diesel fuel on the low-load combustion and emission characteristics of ethanol/diesel RCCI was studied and compared with the conventional combustion mode(CCM).During the experimental study,the rotation speed of engine was 1500 r/min,the total cycle energy was 1 281 J,the ethanol energy premixed ratio was 40%,the SOI timing was-6,-15,-24,-40°CA ATDC,respectively,and brake mean effective pressure(BMEP)was 0.098,0.106,0.109,0.093 MPa,respectively.The results showed that,in terms of combustion characteristics,with the advance of SOI timing,the heat release rate of the cold flame stage of RCCI was advanced,the heat release rate increased,and the duration increased.During the stage of high temperature heat release,with the advance of SOI timing,the instantaneous heat release rate of RCCI increased first and then decreased,the in-cylinder average temperature peak gradually increased,and the combustion duration gradually increased,the combustion center of gravity(CA50)was advanced first and then postponed,and the maximum cumulative heat release gradually increased.Compared with the CCM,RCCI had a longer ignition delay,slower combustion speed,longer combustion duration,and lower combustion temperature.With the advance of SOI,the difference of combustion characteristics between CCM and RCCI gradually increased.In terms of emission characteristics,as SOI advances,the NOx emission at RCCI first increased and then decreased,HC gradually decreased,and CO first decreased at a small rat
作者
韩伟强
李博仑
董超
潘锁柱
李鑫
Han Weiqiang;Li Bolun;Dong Chao;Pan Suozhu;Li Xin(Key Laboratory of Fluid and Power Machinery,Ministry of Education,Xihua University,Chengdu 610039,China;Key Laboratory of Automotive Measurement,Control and Safety,Xihua University,Chengdu 610039,China;National Automobile Quality Supervision and Test Center,Xiangyang 441004,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2018年第20期59-66,共8页
Transactions of the Chinese Society of Agricultural Engineering
基金
四川省教育厅项目(14ZB0128)
西华大学校重点基金(z1520313)
西华大学研究生创新基金(ycjj2017087
ycjj2017085)
关键词
柴油机
燃烧
排放控制
喷油定时
活性控制压燃
乙醇
颗粒物
diesel engines
combustion
emission control
start of injection timing
reactivity controlled compression ignition
ethanol
particulate matter
