High Pressure Optical Chamber for Fuel Injection and Spray Study

在清洁燃烧模式，如柴油低温燃烧（LTC）中，深入了解燃油喷雾变得非常重要。在柴油LTC中，为了实现低燃烧温度，从而同时实现超低烟尘和氮氧化物（NOx）排放，必须形成稀薄、稀释和均匀的气缸装药。在混合物的非均质区域，高温燃烧盛行并导致烟尘和NOx排放。更重要的是使生物燃料在柴油发动机中清洁燃烧，保持高效率。燃油喷射的发展主要取决于对空气-燃料混合均匀性的影响。在PI的研究中，开发了复杂的喷射压力和定时控制，以有效地改善燃油/空气混合。例如，使用现代共轨喷射系统，柴油在上游压力水平喷射到700~2200bar。提高喷射压力是为了提高燃油的雾化和蒸发，改善燃油喷射质量。此外，为了实现均匀的压缩点火，通常采用多次提前喷射策略。因此，如果在特定的时间或曲柄角已知喷射燃料的分布和特性，对于喷射控制和策略开发将是非常关键和具有成本效益的，特别是在生物燃料和多燃料研究中。使用激光和高速成像技术进行详细的定量评估和质量分析是一种特权。所要求的设备是一个EFS InjetVision室系统，可以模拟柴油发动机在喷射事件中的缸内压力。该系统可以无缝集成到我们现有的EFS注入测试台。在该光学室中进行喷雾试验时，可以用高速摄像机从不同视角清晰地记录喷射燃料的喷雾，从而可以定量分析喷淋的二维和三维几何形状。注射过程可以通过时间分辨图像表现出来。光学分析将阐明燃料的分布、雾化及其与空气的混合。

In-depth understanding of fuel sprays becomes very important in clean combustion modes, such as diesel low temperature combustion (LTC). In diesel LTC, it is essential to form a lean, diluted and homogeneous cylinder charge in order to achieve low combustion temperatures and thus simultaneously ultra-low soot and nitrogen oxides (NOx) emissions. In the heterogeneous regions of the mixture, high temperature combustion prevails and leads to soot and NOx emissions. It is more important to enable biofuel clean combustions in diesel engines maintaining high efficiency. The fuel spray development is critically attributed to the impacts on the air-fuel mixture homogeneity. Sophisticated injection pressure and timing controls have been developed in PI's research to improve the fuel/air mixing effectively. For instance, with modern common rail injection systems, diesel fuel is injected at upstream pressure levels to 700~2200bar. Such elevated injection pressure is sought to enhance the fuel atomization and evaporation and to improve the fuel spray quality. Additionally, multiple-shot early injection strategies are generally applied to achieve homogeneous compression ignition. Thus, it will be very critical and cost effective for injection control and strategy development if the distribution and characteristics of the injected fuel are known at specific time or crank angle, particularly for biofuel and multi-fuel studies. It is a privilege to perform detailed quantitative evaluation and quality analyses using laser and high speed imaging technologies with a visually accessible chamber. The requested equipment is an EFS InjetVision Chamber system that can simulate the in-cylinder pressure of diesel engines with injection events. The system can be seamlessly integrated into our existing EFS injection testing bench. When spray tests are carried out in such an optical chamber, the injected fuel sprays can be clearly recorded with high speed camera from different viewing angles, making it feasible to quantitatively analyze the spray geometries in 2D and 3D. The injection process can be manifested by the time-resolved images. The optical analyses will cast light on the fuel distribution, atomization, and its mixing with air.