预混比和喷油定时对异丁醇/柴油RCCI燃烧与排放特性的影响  

Effect of premixing ratio and start of injection on RCCI combustion and emission characteristics fueled with iso-butanol/diesel

作　　者：韩伟强 卢耀[1,2] 黄泽远 刘兴文 张鹏 潘锁柱[1,2] Han Weiqiang;Lu Yao;Huang Zeyuan;Liu Xingwen;Zhang Peng;Pan Suozhu(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;Key Laboratory of Shaanxi Province for Development and Application of New Transportation Energy,Chang’an University,Xi’an710061,China)

机构地区：[1]流体及动力机械教育部重点实验室(西华大学),成都610039 [2]汽车测控与安全四川省重点实验室(西华大学),成都610039 [3]交通新能源开发、应用与汽车节能陕西省重点实验室(长安大学),西安710061

出　　处：《农业工程学报》2019年第9期88-96,共9页Transactions of the Chinese Society of Agricultural Engineering

基　　金：四川省科技厅青年科技创新研究团队(2017TD0026);汽车测控与安全四川省重点实验室(西华大学)开放课题(szjj2018-131);交通新能源开发、应用与汽车节能陕西省重点实验室(长安大学)开放基金资助(300102229510);西华大学研究生创新基金(ycjj2018096)

摘　　要：通过在一台六缸增压柴油机上进行了异丁醇/柴油双燃料活性控制压燃(reactivity controlled compression ignition,RCCI)的试验,探究了异丁醇作为低活性燃料在不同的预混比(premixing ratio,Rp)和喷油定时(start of injection,SOI)下对发动机燃烧和排放特性的影响。结果表明,随着SOI的提前,点火延迟(ignition delay, ID)延长,放热率峰值(maximumheat release rate,HRRm)先增大后减小;在排放方面,THC和CO的排放水平降低,NOx呈现先升高后降低的趋势,而在 Rp=30%~50%时,颗粒物(particle matter,PM)的排放呈现先降低后升高的变化,当 Rp=60%时则只表现出了降低的趋势。此外,随着异丁醇Rp的增加,ID和燃烧持续期(combustion duration,CD)都增长,HRRm降低;在排放方面,THC和CO排放升高,NOx排放降低,而PM排放在 Rp=30%下具有最高的水平,Rp=40%和 Rp=50%时则都显示出较低的水平,而在 Rp=60%下整体有所升高。此外,粒径分布显示 3~30 nm 的核态颗粒物(nuclear particle matter,PMN)排放数量最高,但质量占比非常小。而在PM排放质量分布中,主导的PM是粒径为 30~500 nm 的积聚态颗粒物(accumulatedparticle matter,PMA)。Reactivity control compression ignition (RCCI) has been shown to be effective in reducing nitrogen oxides (NOx) and particle matter (PM). A significant feature of RCCI is the ability to control the combustion process by creating reactivity stratification in the cylinder, which could reduce emissions. Since iso-butanol has a higher octane number, it can enhance the gradient of reactivity stratification, which will facilitate the control of combustion. The effect of iso-butanol on engine combustion and emission characteristics was investigated on a six-cylinder turbocharged diesel engine under RCCI combustion mode. In this study, iso-butanol (low reactivity fuel) was provided through the port injection (PI), and the diesel (high reactivity fuel) was injected directly into the cylinder. In the test, the combustion and emission characteristics of RCCI fueled with iso-butanol and diesel were investigated with different fuel supply strategies by changing the premixing ratio (Rp) of iso-butanol and the start of injection (SOI) of diesel under low engine load. Four different premix ratios were selected, including 30%, 40%, 50% and 60%, and five different SOIs were designed, including -8°,-12°,-18°,-24° and -30°crank angle after top dead center (°CA ATDC). In this study, the engine was operated at a constant speed of 1 500 r/min, maintaining the brake mean effective pressure (BMEP) and the total cycle energy at 0.3 MPa and 1 280 J, respectively. The results showed that, with the advancement of SOI, the ignition delay (ID) was prolonged and the maximum heat release rate (HRRm) was increased first and then decreased. In terms of emission characteristics, with the advancement of SOI, the emission level of THC and CO decreased, and NOx emission increased first and then decreased. As SOI was further advanced to -30 °CA ATDC, it can be seen that the emission of CO increased when Rp was 30% or 40%. While the emission of PM at Rp from 30% to 50% showed a trend of decreasing first and then increasing, when Rp was 60%, it on

关 键 词：柴油机 燃烧 排放控制 异丁醇 RCCI 喷油定时 预混比 颗粒物 

分 类 号：TK427[动力工程及工程热物理—动力机械及工程]