缸内直喷汽油机冷启动燃烧与排放光学试验研究  

Study on Combustion and Emission of Cold Start for Gasoline Direct Injection Engine Based on Optical Experiments

作　　者：刘国庆[1,2] 

机构地区：[1]天津大学内燃机燃烧学国家重点实验室,天津300072 [2]奇瑞汽车股份有限公司发动机工程研究院,芜湖241009

出　　处：《中国机械工程》2013年第23期3164-3169,3254,共7页China Mechanical Engineering

基　　金：内燃机燃烧学国家重点实验室开放课题基金资助项目(K2010-04)

摘　　要：结合光学单缸机和激光诱导荧光测量技术对直喷汽油机冷怠速工况缸内油气混合与燃烧过程进行了可视化试验研究。试验采用了屋脊形透明缸套和双侧激光,利用统计图像评估方法得到了缸内混合气浓度和燃烧火焰分布图像,通过缸压传感器和燃烧分析仪对燃烧稳定性进行了分析,采用废气分析仪和光学传感器分别对碳氢和碳烟排放进行了分析评估。研究表明:燃烧稳定时燃油与缸套碰壁是碳氢排放产生的主要原因,碳烟排放则主要由活塞顶部燃油碰壁造成;适当推迟第二次喷油时刻有利于点火时刻火花塞附近稳定浓混合气的形成,继而提高燃烧稳定性,同时减少碳氢排放,过迟喷射会导致碳烟明显增加,过早喷射会造成缸内失火,碳氢排放增加。Optical single cylinder engine and planar laser induced fluorescence technology were used to visualize in--cylinder air fuel mixing and combustion process of cold idle situation for gasoline direct injection engine. Transparent liner with pent--roof shape at the upper side and double sides split laser were used. Using statistical image evaluation method, images of the in--cylinder fuel con- centration and combustion flame were obtained. Combustion stability was evaluated by cylinder pres- sure sensor and combustion analyzer. Exhaust gas analyzer and optical sensor were used to analyze hydrocarbon and soot emission separately. The results show that, HC emission is caused mainly by fuel impingement on cylinder liner at stable combustion situation, while soot is formed mainly by combustion o{ fuel {ilm at the top side of piston. Suitable retarded injection time for the second injec- tion is helpful to form stable rich fuel--air mixture near sparkplug, and then improve combustion sta- bility and HC emission; too late fuel injection will increase soot emission dramatically, and too early injection will cause misfire, and increase HC emission.

关 键 词：缸内直喷 光学发动机 平面激光诱导荧光 冷启动 燃烧 排放 

分 类 号：TK411.2[动力工程及工程热物理—动力机械及工程]