摘要
采用激光阴影的方法,在喷雾定容弹试验台上研究了不同边界条件对压电晶体外开式汽油喷油器的喷雾形态的影响,压电晶体外开式汽油喷油器的应用主要是针对喷雾引导分层燃烧,试验边界条件依据分层燃烧的实际缸内条件设定。研究结果表明压电晶体喷油器喷雾形态呈现明显的油线结构,随着喷雾的发展,清晰的油线边界逐渐模糊。喷油压力和环境背压的增加都会使贯穿距曲线中喷雾破碎雾化的拐点提前,有利于燃油的雾化。高环境背压使喷雾形态中产生明显的涡流回旋区,将破碎的小粒径燃油输送到喷雾的上方,使火花塞附近形成易于点燃的混合气。环境温度的升高会导致涡流回旋区在0.4 ms时发生坍塌,不利于分层燃烧的实现,因此利用压电晶体喷油器实现喷雾引导分层燃烧时,晚喷的喷油脉宽不宜过长。燃料温度的升高对于前期喷雾形态影响不大,0.6ms之后,高温燃料的喷雾发生明显坍塌,贯穿距和喷雾锥角明显减少。
The spray characteristics of gasoline piezo outward-opening injector was studied at different boundary conditions in spray constant volume chamber by shadow method. The boundary condition was set according to actual in-cylinder condition with stratified combustion. The results show that the spray consists of many fuel strings and the string becomes blur as the spray develops with time. The increase of injection pressure and back pressure advances the spray breakup turning point on penetration distance curve. The spray structure would produce swirl region which would transfer fuel with small diameter to upper part to form rich mixture around spark plug, but the increase of back temperature can disappear the swirl region from 0.4ms which is harmful to stratified combustion. As a result, when the piezo injector is used to realize spray-guided stratified combustion, the pulse width of late injection should be shorter. Fuel temperature has little influence on spray pattern at earlier stage and the high temperature fuel would occur more obvious collapse after 0.6ms which results in the decrease of spray penetration distance and spray angle.
出处
《小型内燃机与车辆技术》
2015年第5期31-37,共7页
Small Internal Combustion Engine and Vehicle Technique
关键词
压电晶体外开式喷油器
汽油
喷雾贯穿距
喷雾锥角
阴影法
Piezo outward-opening injector, Gasoline, Spray penetration distance, Spray angle, Shadowmethod
