Investigations of split injection properties on the spray characteristics using a solenoid high-pressure injector
Investigations of split injection properties on the spray characteristics using a solenoid high-pressure injector
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DOI：
10.1177/1468087420985372
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发表时间：
2021-01
影响因子：
2.5
通讯作者：
Meghnaa Dhanji;Hua Zhao
中科院分区：
文献类型：
--
作者：
Meghnaa Dhanji;Hua Zhao
汽油直喷（GDI）发动机的持续挑战是在冷启动期间实现排气催化剂的快速活化，以减少氮氧化物（NOx）排放。在压缩冲程后期喷射，以形成分层混合物，使得燃料没有足够的时间被周围的充量夹带。这导致局部富燃料扩散燃烧和高水平颗粒物质的形成。采用分次注入策略可以帮助解决这些问题。本文研究了分段喷射策略对喷雾特性的影响。采用电磁阀驱动的高压喷油器研究了不同脉冲宽度（PW）组合、分流比和停留时间。研究了靶羽流的喷射量和液滴特性。实验在定容喷雾室中进行。采用相位多普勒粒子风速仪（PDA）测量液滴速度和尺寸。研究了0.3-0.8 ms范围内的短PW和大PW。结果表明，最高喷射量的燃料测量与最短的停留时间为2 ms，由于增加的喷射事件之间的相互作用，这导致更大的索特平均直径（SMD）测量。0.4 ms较短PW的SMD通常大于0.8 ms PW。在这种情况下，液滴受到电磁阀的紧密间隔的打开和关闭事件的影响。
An on-going challenge with Gasoline direct injection (GDI) engines is achieving rapid activation of the exhaust catalyst during cold starts, in order to reduce the Nitrogen Oxide (NOx) emissions. Injecting late in the compression stroke, in the efforts to form a stratified mixture, provides the fuel insufficient time to be entrained with the surrounding charge. This results in locally fuel rich diffusion combustion and the formation of high levels of particulate matter. Employing a split injection strategy can help tackle these issues. The current study examines the effects of a split injection strategy on the spray characteristics. Varying pulse width (PW) combinations, split ratios and dwell times are investigated using a Solenoid actuated high pressure injector. The injected quantity and the droplet characteristics of a target plume are investigated. The experiments were performed in a constant volume spray chamber. The droplet velocities and sizes were measured using Phase Doppler Particle Anemometry (PDA). Short and large PWs, in the range of 0.3–0.8 ms, were investigated. The results revealed that the highest injected quantity of fuel was measured with the shortest dwell time of 2 ms, owing to increased interactions between the injection events, which led to larger Sauter mean diameters (SMDs) measured. The SMDs for the shorter PW of 0.4 ms were generally larger than 0.8 ms PW. The droplets in this case were affected by the closely spaced opening and closing events of the Solenoid valve.