焰前放热对GCI发动机燃烧性能的影响  

Effect of Pre-Ignition Heat Release on Combustion Performance of GCI Engines

作　　者：李宪宇 潘家营[1] 刘峰[1] 卫海桥[1] 刘昌文[1] 舒歌群[1] Li Xianyu;Pan Jiaying;Liu Feng;Wei Haiqiao;Liu Changwen;Shu Gequn(State Key Laboratory of Engines,Tianjin University,Tianjin 300350,China)

机构地区：[1]天津大学内燃机燃烧学国家重点实验室,天津300350

出　　处：《内燃机学报》2021年第6期481-487,共7页Transactions of Csice

基　　金：国家重点研发计划资助项目(2017YFE0102800);国家自然科学基金资助项目(51706152).

摘　　要：汽油压燃(GCI)发动机燃用低辛烷值(RON=60~80)燃料时具有更佳的燃烧和排放性能.低辛烷值燃料具有低温反应特性,存在明显的焰前放热现象,对发动机着火及燃烧过程产生重要作用.基于一台高压缩比单缸机,选用研究法辛烷值为75的甲苯标准参考燃料(TPRF),研究了不同喷油时刻、进气温度、进气压力和辛烷值敏感度下的焰前放热特性及其对GCI发动机燃烧性能的影响.结果表明:当喷油时刻提前至上止点前90°CA以上时存在明显的焰前放热现象;提高进气压力或降低进气温度会促进低温化学反应,焰前放热增强,在负温度系数区域,提高进气温度会使滞燃期延长,主燃烧相位滞后;降低燃料辛烷值敏感度会提高混合气低温反应活性,促进焰前放热重心及主燃烧相位提前.Gasoline compression ignition(GCI)engines have better combustion and emission performance when fueled with low-octane number(RON=60-80)fuels.However,low-octane number fuels with low-temperature reactions are manifested by the obvious pre-ignition heat release,which affects the ignition and combustion proc-esses of GCI engines.In this work,a single-cylinder engine with high compression ratio and toluene primary refer-ence fuels(TPRF)(RON=75)was employed,and the influence of injection timing,intake temperature,intake pressure and octane sensitivity on the pre-ignition heat release and thereby combustion performance of GCI engines were investigated.The results show that the pre-ignition release behavior occurs when the injection time is advanced to the crank angle of earlier than 90°CA.Elevating intake pressures and decreasing intake temperatures both can enhance low-temperature reactions and improve the magnitude of pre-ignition heat release.In the negative tempera-ture coefficient region,increasing the intake temperatures can prolong the ignition delay period and slow the com-bustion phase.The decrease of octane sensitivity improves the low-temperature reactivity of fuels,which facilitates the advancement of pre-ignition heat release center and main combustion phase.

关 键 词：汽油压燃发动机 焰前放热 辛烷值敏感度 进气条件 燃烧相位 

分 类 号：TK437[动力工程及工程热物理—动力机械及工程]