Control of the Start of Homogeneous Charge Compression Ignition Combustion by Radical Jet

为了考察正丁烷/空气混合气自燃的基本特征和脉冲喷雾点火均质压燃燃烧的基本特征，在小型快速压气机上进行了燃烧试验。得出了以下结论：(1)在均质压燃燃烧中，由于压缩过程中燃烧室内温度分布的不均匀，燃烧室内并不同时发生自燃，而是在燃烧室内大面积燃烧，随后是全尺寸燃烧。(2)从燃烧室内火花放电开始，射流在1毫秒内开始从点火器孔口喷出，射流图像强度一度变弱，然后在燃烧室内发生大范围燃烧。(3)脉冲喷雾点火燃烧的光发射特性与自燃燃烧相似，尤其是“蓝光”现象。因此，火焰并没有从射流中持续传播，但从PFJ点火器发出的射流在燃烧室中起到了触发燃料自燃的作用。

In order to examine fundamental features of autoignition of n-butane/air mixtures and HCCI combustion initiated by PFJ, combustion tests were carried out using the compact Rapid Compression Machine. These led to the following conclusions.(1)In HCCI combustion, autoignition did not occur everywhere in the combustion chamber at the same time due to the existence of non-unified temperature distribution in the chamber during compression, however, the combustion started across a wide area in the chamber, which was followed by the full-scale combustion.(2)The jet began to issue from the orifice of the PFJ igniter within one millisecond from the beginning of the spark discharge in the cavity, and the intensity of the jet image once became weak, and then the combustion occurred across a wide area in the combustion chamber, which was similar to the autoignition case.(3)The light emission characteristics of combustion initiated by PFJ were similar to those of autoignition case, especially the behavior of "Blue light". Thus the flame did not propagate continuously from the jet, but the jet issuing from the PFJ igniter behaved as a trigger for the autoignition of the fuel in the combustion chamber.