一种高频高能点火系统放电特性及其对早期火焰发展影响的研究  

Discharge Characteristics of a High-Frequency High-Energy Ignition System and the Effect on Earlier Flame Propagation

作　　者：叶昌[1] 祝华 李雪松[1] 郑明 许敏[1] YE Chang;ZHU Hua;LI Xuesong;ZHENG Ming;XU Min(School of Mechanical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Department of Mechanical,Automotive and Materials Engineering,University of Windsor,ON N9B 3P4,Canada)

机构地区：[1]上海交通大学汽车电子国家工程实验室,上海200240 [2]温莎大学发动机清洁燃烧实验室,温莎加拿大N9B3P4

出　　处：《车用发动机》2020年第1期10-19,共10页Vehicle Engine

摘　　要：设计了一种高放电频率、高点火能量的火花放电点火系统,利用准纳秒级伏安特性测试和定容室燃烧试验,系统地研究了该高频高能点火系统的放电特性,以及放电频率、单次放电延时等参数对可燃混合气的初始火核形成和早期火焰发展的影响。结果表明:对比普通的高频点火,该点火系统放电电流更大,相同的放电频率和放电时长下火花塞释放的点火能量更大。增加放电频率,点火能量随之增加,当频率为5kHz时,点火能量约为60mJ,当频率上升到15kHz时,点火能量上升到150mJ,表明点火能量随着放电频率的变化具有良好的相关性。增加单次放电延时也可以获得更高的点火能量,在0μs放电延时情况下,点火能量约为60mJ,放电延时逐步增加到40μs时,点火能量增加到150mJ。记录放电期间火弧变化的图像,可以观察到高频高能点火明显亮于普通高频点火,说明该点火方式具有更大的放电体积和能量。提高放电频率、增加单次放电延时,高频高能点火的火弧持续时间更长,更容易呈现出火弧连续放电的特性。定容室燃烧试验对比结果表明高频高能点火可以形成更大的火核体积和更加稳定的初始火焰,且增加放电频率和延长单次放电延时,可以进一步加速燃烧过程。An innovative high-frequency high-energy spark discharge ignition system was designed.Then the system discharge characteristics and the influences of discharge frequency and single-discharge delay on initial flame kernel formation and earlier flame propagation were studied by using quasi-nanosecond volt-ampere testing and constant volume combustion experiment.The results showed that the high-frequency high-energy ignition system had the higher discharge current and larger ignition energy than traditional high-frequency ignition system in the same discharge duration and discharge frequency.The ignition energy was 60 mJ when the frequency was 5 kHz and 150 mJ when it rose to 15 kHz.The ignition energy increased with the increase of discharge frequency,which meant that ignition energy had a strong correlation with discharge frequency.In addition,increasing the single-discharge delay could also achieve larger ignition energy.The ignition energy was around 60 mJ when the discharge delay was 0μs and 150 mJ when it increased to 40μs.It was observed that the high-frequency high-energy ignition was brighter than traditional high-frequency ignition according the recorded images of fire arc variation,which meant that the referred ignition had larger ignition volume and stronger energy density.Increasing discharge frequency and single-discharge delay prolonged the ignition fire arc duration,which made it easier to show the continuous discharge characteristics.The combustion experiment in a constant volume combustion chamber finally showed that the high-frequency high-energy ignition could form a larger flame kernel volume and a more stable initial flame and the increase of discharge frequency and single-discharge delay could further improve combustion process.

关 键 词：稀薄燃烧 火花放电点火 高频点火 高能点火 

分 类 号：TK413.9[动力工程及工程热物理—动力机械及工程]