Quantitative Three Dimensional Measurement of Fuel Vapor Concentration via Silicone Oil Particle Scattering Imaging Method

为了弄清内燃机中燃油蒸气分布与燃烧特性之间的关系，采用激光片散射技术和快速响应FID法分别测量了瞬态燃油喷雾和模拟分层装药燃烧的定容燃烧室中的燃油蒸气分布。将硅油颗粒散射成像（SSI）技术应用于蒸发瞬态喷雾中，实现了燃油蒸汽的二维序列可视化。该方法利用悬浮在燃油蒸气中的残余硅油颗粒作为散射示踪剂，利用高速图像转换相机以20000 fps的帧速对硅油颗粒在铜蒸气激光照射下的散射进行成像。结果表明，蒸发喷雾中富混合团簇的间歇周期性运动与自由瞬态气体射流中的涡旋运动相似。为了研究混合浓度的不均匀性对分层装药燃烧系统中燃烧的影响，使用一个精心控制的实验系统对这些影响进行了研究。设计了一种恒容腔体，通过在腔体内部使用去除隔板来模拟理想的分层装药。通过指示压力分析、纹影摄影、离子探针测量和使用快速响应FID技术的局部等效比测量来检查流动和燃烧特性，同时改变分区两侧的初始等效比的燃烧。结果表明，富侧当量比对分层装药混合物的燃烧特性有较大影响，燃烧速度比均质装药的燃烧速度快。

To make clear the relation between the distribution of fuel vapor and the combustion characteristics in I.C.engines, the fuel vapor distributions in a transient fuel spray and in a constant volume chamber which can simulate the stratified charge combustion are measured by a laser sheet scattering technique and by a fast response FID method respectively.The new imaging technique, which is called as silicone oil particles Scattering Imaging (SSI) method, is applied on an evaporating transient spray for visualizing the fuel vapor two dimensionally and sequentially. In this method, the residual silicone oil particles suspended in fuel vapor are used as the scattering tracers, and the scattering from the silicone oil particles which are illuminated by a sheet of light of copper vapor laser is imaged by a high speed image converter camera with a framing speed of 20,000fps. The results make clear that the intermittent and periodical motion of rich mixture cluster in an evaporating spray is similar to that of vortices in a free transient gas jet.To investigate the effects of inhomogeneity of mixture concentration on the combustion in stratified charge combustion system, these effects are examined using a carefully controlled experimental system. A constant volume chamber, which can simulate an idealized stratified charge by using a removal partition inside the chamber, is developed. Flow and combustion characteristics are examined by indicated pressure analysis, Schlieren photography, ion probe measurements and local equivalence ratios measurements using the fast response FID technique while varying the combustion of initial equivalence ratios on each side of the partition. As a result it is clarified that the combustion characteristics of stratified charge mixtures are strongly effected by rich side equivalence ratio and the combustion speed is enhanced compared to homogeneous charge case.