Investigation of spray characteristics from a low-pressure common rail injector for use in a homogeneous charge compression ignition engine
Investigation of spray characteristics from a low-pressure common rail injector for use in a homogeneous charge compression ignition engine
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DOI：
10.1088/0957-0233/15/3/003
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发表时间：
2004-01
影响因子：
2.4
通讯作者：
Kihyung Lee;R. Reitz
中科院分区：
文献类型：
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作者：
Kihyung Lee;R. Reitz
均质充量压缩点火（HCCI）燃烧提供极低水平的污染物排放，因此是未来IC发动机的有吸引力的替代方案。为了在发动机气缸内实现均匀的混合物分布，燃料喷雾的特性在HCCI发动机概念中起重要作用。众所周知，主要用在柴油发动机中的高压共轨喷射系统由于燃料直接冲击在燃烧室表面上的可能性而实现差的混合物形成。本文介绍了一种用于HCCI发动机的低压共轨喷油器的喷雾特性。光学诊断，包括激光衍射和相位多普勒方法，和高速摄像机摄影，被应用到测量喷雾液滴直径和调查喷雾发展过程。将激光衍射法的液滴尺寸测量结果与相位多普勒粒子分析仪（PDPA）的液滴尺寸测量结果进行了比较，以验证实验的准确性。此外，燃料性质对喷雾特性的影响进行了研究，使用正庚烷，斯托达德溶剂（汽油替代品）和柴油燃料，因为HCCI燃烧是敏感的燃料组成。结果表明，该喷嘴形成空心锥片状喷雾而不是液体射流，雾化效率高（产生小液滴）。液滴SMD范围为15至30 µm。喷雾破碎特性被发现取决于燃料的性质。正庚烷的裂解时间短，油滴SMD小于Stoddard溶剂和柴油。
Homogeneous charge compression ignition (HCCI) combustion provides extremely low levels of pollutant emissions, and thus is an attractive alternative for future IC engines. In order to achieve a uniform mixture distribution within the engine cylinder, the characteristics of the fuel spray play an important role in the HCCI engine concept. It is well known that high-pressure common rail injection systems, mainly used in diesel engines, achieve poor mixture formation because of the possibility of direct fuel impingement on the combustion chamber surfaces. This paper describes spray characteristics of a low-pressure common rail injector which is intended for use in an HCCI engine. Optical diagnostics including laser diffraction and phase Doppler methods, and high-speed camera photography, were applied to measure the spray drop diameter and to investigate the spray development process. The drop sizing results of the laser diffraction method were compared with those of a phase Doppler particle analyser (PDPA) to validate the accuracy of the experiments. In addition, the effect of fuel properties on the spray characteristics was investigated using n-heptane, Stoddard solvent (gasoline surrogate) and diesel fuel because HCCI combustion is sensitive to the fuel composition. The results show that the injector forms a hollow-cone sheet spray rather than a liquid jet, and the atomization efficiency is high (small droplets are produced). The droplet SMD ranged from 15 to 30 µm. The spray break-up characteristics were found to depend on the fuel properties. The break-up time for n-heptane is shorter and the drop SMD is smaller than that of Stoddard solvent and diesel fuel.