摘要
对发动机喷油系统参数对二甲醚(DME)喷雾燃烧过程的影响进行了实验研究,包括喷孔直径和喷油提前角对喷雾燃烧过程的影响.研究结果表明,喷孔直径对DME着火滞燃期和燃烧持续期几乎没有影响.喷孔直径增大,喷雾核心贯穿距增大,燃烧火焰在壁面附近持续时间延长;对于小孔径喷油嘴,燃烧火焰在喷嘴附近持续时间较长,在燃烧中后期可以看到明显的火焰亮光,表明小孔径喷油嘴易产生泄漏,而且随着孔径减小,亮度加强,泄漏越严重;示功图分析结果表明,喷孔直径增大,缸内工质平均温度升高,平均有效压力增大,大孔径喷油嘴有利于提高发动机热效率,但会导致NOx排放升高.在实验条件相当的情况下,喷油提前角对二甲醚着火滞燃期和燃烧持续期几乎没有影响.
The influence of injection parameters including the nozzle diameter and injection timing on the spray and combustion process of dimethyl ether (DME) was investigated. By the contrast of photographs of different nozzle diameters, there were almost no differences in ignition delay and combustion duration. With increasing in the nozzle diameter, the wall combustion portion increases. For nozzle with smaller orifice, a weak light near the nozzle can be seen at the middle and end of combustion. It indicates that some leakages have happened at that time. The results also show that bigger orifice has higher IMEP and higher mean cylinder temperature, which can result in higher NOx emissions. Therefore, bigger nozzle orifice diameter has an active effect on engine thermal efficiency. In our experimental condition, the injection timing almost has no influence in the ignition delay and combustion duration. However, with delaying the injection timing, the temperature in cylinder will increase in this experimental engine.
出处
《燃烧科学与技术》
EI
CAS
CSCD
2003年第4期339-343,共5页
Journal of Combustion Science and Technology
基金
国家自然科学基金资助项目(59976028).
