摘要
讨论了用激光诱导荧光法测量发动机缸内混合气浓度分布时的主要技术问题以及示踪剂特性,对比并改进了定量标定中分步求解标定系数的方法,改进后的标定计算方法没有忽略沿程吸收衰减的步骤。建立了基于光学发动机的缸内平面激光诱导荧光法测试平台,定量研究了直喷汽油机在不同喷射策略下的混合气分布。测试结果表明:对于稀燃策略,在进气冲程的早喷形成难以点燃的低浓度均匀场,同样油量在压缩冲程单次喷射会在缸内形成燃空当量比2以上的过浓区域,而两阶段喷射形成的混合气不仅较为均匀,且在火花塞附近形成了燃空当量比1.2左右的浓区,有利于稳定点火和燃烧。对火花塞附近区域的统计结果表明:火花塞附近处于最适合点火燃空比范围的混合气变动量总体小于10%。
The laser-induced fluorescence （LIF） technique for measurement of in-cylinder mixture distribution and the characteristics of tracer were discussed and an improved calibration method was developed. No assumption in absorption attenuation was needed in this method. A planar laser-induced fluorescence （PLIF） test bench was built for measurement of air-fuel mixture distribution at ignition moment in different injection strategies. Measured results of equivalence ratio in the zone near the spark plug at ignition moment were imaged. The result shows that for the lean burn mode, the early injection in intake stroke leads to a low concentration homogenous mixture which is hard to be ignited. While the later injection in compression stroke forms an over-rich zone of equivalence ratio above 2. The two-stage injection brings about a relative homogenous mixture with a rich zone of equivalence ratio around 1.2 near the spark plug which is suitable for a steady lean burn. Mixture in the rich zone near the spark plug shows its variation is below 10 %.
出处
《内燃机工程》
EI
CAS
CSCD
北大核心
2010年第4期1-5,10,共6页
Chinese Internal Combustion Engine Engineering
关键词
内燃机
直喷汽油机
激光诱导荧光
缸内混合气分布
IC engine
gasoline direct injection（GDI）
laser-induced fluorescence（LIF）
in-cylinder mixture distribution
