GDI发动机中不同燃料射流特性的试验研究

doi:10.19562/j.chinasae.qcgc.2023.01.010

摘要/Abstract

摘要：

直喷汽油（ GDI）发动机中闪沸喷雾具有促进油气混合的优势，但其发生喷雾坍塌的现象会对燃烧与排放带来不利，并且研究发现喷雾坍塌与单射流行为密切相关。因此，为了减轻喷雾坍塌并充分利用GDI发动机中闪沸喷射的优势，了解闪沸射流行为极其重要。本文选择了由5孔喷油器改造而成的单孔喷油器，选用正己烷与异辛烷燃料，在定容燃烧弹中进行试验研究。所选燃油温度为30到130 ℃，环境背压为0.2到1 bar。通过分析射流宽度与过热度、成核速率、化学势以及环境背压等不同参数的关系，发现射流宽度与 $? μ · p a m b - 0.5$ 的相关性达到0.9以上，表明具有较好的相关性，且在近喷口附近射流宽度由相变化学势与环境背压所影响。

关键词: GDI喷雾, 闪急沸腾, 射流形貌, 化学势

Abstract:

Flash-boiling spray in gasoline direct injection （GDI） engines has the advantage of promoting mixing of oil and gas， but the phenomenon of spray collapse is detrimental to combustion and emission， and studies have found that spray collapse is closely related to single-jet behavior. Therefore， in order to mitigate spray collapse and take full advantage of flash boiling jets in GDI engines， it is extremely important to understand the behavior of flash boiling jet. In this paper， a single-hole fuel injector modified from a five-hole fuel injector is selected， and n-hexane and isooctane fuel are selected to conduct experimental research in a constant volume combustion bomb. The selected fuel temperature is 30 to 130 ℃ and the ambient pressure is 0.2 to 1 bar. By analyzing the relationship between the jet width and different parameters such as superheat degree， nucleation rate， chemical potential and environmental ambient pressure， it is found that the correlation between the jet width and $? ? μ · p a m b - 0.5$ is more than 0.9， which has a good correlation， indicating that the jet width near the nozzle is affected by the phase change potential and the environmental ambient pressure.

Key words: GDI spray, flash boiling, jet morphology, chemical potential

刘国栋,任桂周,赵子杰,张景宇,李雁飞. GDI发动机中不同燃料射流特性的试验研究[J]. 汽车工程, 2023, 45(1): 86-92.

Guodong Liu,Guizhou Ren,Zijie Zhao,Jingyu Zhang,Yanfei Li. An Experimental Study on Characteristics of Different Fuel Jets in GDI Engine[J]. Automotive Engineering, 2023, 45(1): 86-92.

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参数	数值
喷射燃料	正己烷、异辛烷
喷射压力/MPa	10
喷射脉宽/ms	2.0
环境温度/℃	室温
环境背压/bar	0.2、0.4、0.6、0.8、1
燃油温度/℃	30、50、70、90、110、130

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