用PLIF测量GDI发动机滚流平面的混合气浓度  

Mixture Distribution Measurement in the Tumble Plane of a GDI Engine via PLIF Method

作　　者：梁帅[1] 张周 丁海春 马骁[1] 李雁飞[1] 徐宏明[1,2] Liang Shuai;Zhang Zhou;Ding Haichun;Ma Xiao;Li Yanfei;Xu Hongming(State Key Laboratory of Automotive Safety and Energy,Tsinghua University,Beijing 100084,China;School of Mechanical Engineering,University of Birmingham,Birmingham B15 2TT,United Kingdom)

机构地区：[1]清华大学汽车安全与节能国家重点实验室,北京100084 [2]伯明翰大学机械工程系

出　　处：《内燃机学报》2018年第6期481-490,共10页Transactions of Csice

基　　金：国家自然科学基金资助项目(51506111);国家重点研发计划资助项目(2016YFC0202700)

摘　　要：通过一台全透明石英气缸套的汽油缸内直喷光学发动机,利用平面激光诱导荧光法(PLIF)定量测量了发动机滚流平面内的混合气浓度分布.在不同节气门开度及不同喷射策略下研究了缸内混合气分布随曲轴转角的变化,讨论了气流运动强弱、喷射时刻及喷射量对发动机混合气的影响;针对可视区域的平均及局部燃空当量比提出了评价不均匀度,并开展了循环变动分析.结果表明:节气门开度不为0时,单次早喷策略均可在上止点附近形成不均匀度评价指标小于0.14的混合气,且不均匀度随进气流动增强而下降;推迟喷射时,油气混合速度明显加快,单次晚喷及双喷工况在上止点附近均可形成不均匀度评价指标小于0.15的混合气;单次早喷、非怠速工况的平均燃空当量比在上止点附近的循环变动小于0.06,而大部分单次晚喷及双喷工况均大于0.13;局部燃空当量比循环变动较大的区域通常为混合气云团运动方向的前沿,较弱的进气流动及推迟喷射会提高整个有效区域内的循环变动.Quantitative measurement of air-fuel mixture distribution by planar laser induced fluorescence(PLIF)was carried out in an optical gasoline direct injection(GDI)engine with a full-transparent cylinder liner.The mixture distribution under different throttles and injection strategies was examined and the impact of flow intensity,injection timing and mass was discussed.Analysis on inhomogeneity and cycle-to-cycle variations of the averaged and local equivalence ratios was conducted.Results show that under the condition of non-zero throttle with early injections,inhomogeneity under 0.14 can be achieved near TDC,and inhomogeneity decreases as the flow intensity rises.Larger mixing velocity can be observed with retarded injections,and mixture inhomogeneity near TDC is under 0.15 for most retarded injection strategies studied.The cycle-to-cycle variation of the average equivalence ratio is below 0.06 under non-zero throttle and early injection conditions,while it becomes larger than 0.13 under the late injection and double injection strategies.Normally the frontier of the moving mixture cloud has the highest local cycle-to-cycle variation.The weak flow intensity will increase the cycle-to-cycle variation in the whole visible region.

关 键 词：汽油缸内直喷 平面激光诱导荧光法 全透明气缸套 缸内混合气 循环变动 

分 类 号：TK411.2[动力工程及工程热物理—动力机械及工程]