光学诊断在柴油机缸内碳烟测试中的应用

介绍了用于柴油机缸内碳烟测试的4种光学方法的原理和特点,包括消光法、散射法、双色法和激光诱导炽光法。消光法和散射法试验装置简单,数据精确,结合运用可以获得空间一点的碳烟体积分数和粒子尺寸。双色法在获取温度场的同时可以得到碳烟浓度的二维分布,是目前应用较为成熟的测试手段。但这3种方法得到的是碳烟在光程方向的平均结果。激光诱导炽光法采用激光片光对碳烟粒子进行加热,可以获得片光薄层内的碳烟浓度分布。通过比较可以看出,由于激光诱导炽光法可以获得瞬态二维碳烟分布,具有良好的时间、空间分辨率,十分适合缸内碳烟测试。

Optical Diagnostics for Soot Measurement in the Cylinder of Diesel Engine

In the paper,the principles and characteristics of four optical diagnostics for soot measurement in the cylinder of diesel engine are introduced,including light extinction method,light scattering method,two-color method and laser induced incandescence(LII).The test equipments are easy to operate for light extinction test and light scattering test with precise data.The soot volume concentration and particle size of a point can be acquired by the simultaneous extinction and scattering mea-surements.The temperature field and soot distribution can be gotten at the same time by two-color method,which is the most popular technology for soot diagnostics.However the soot concentration acquired by the three methods is average concentration in the direction of optical path.The principle of laser induced incandescence is that soot particle is heated by laser sheet and then the concentration of soot in the laser sheet can be acquired.By comparing the four methods,it is found that because of getting instantaneous two-dimensional soot distribution with well temporal spatial resolution,LII is suited for in-cylinder soot measurement.