【摘要】 高压共轨喷油器的针阀运动规律直接决定了喷油规律和雾化效果,决定针阀运动规律的因素对改进喷油器结构以及提升雾化效果有着重要意义。自行搭建了高压共轨喷油器仿真模型;该计算模型对喷油器的控制油路中进出油节流孔和球阀区域处,有空化和无空化两个阶段的流量系数进行了优化;结合喷油器的理论分析与试验验证,研究了喷油器针阀的运动规律。结果表明:针阀开启过程分为2个阶段,第1阶段开启缓慢,第2阶段开启迅速,针阀关闭过程只有1个阶段;导致针阀开启过程出现2个阶段是由于喷油器控制室内泄油过程的节流位置由球阀开启处转到了回油节流孔;针阀关闭过程为1个阶段是由于球阀与阀座形成的间隙对控制室内回油过程起主要节流作用;轨压主要对针阀开启第2阶段有影响,而对针阀开启第1阶段与关闭阶段影响很小;随着轨压的升高,针阀开启第2阶段开启速度加快,当轨压达到一定值时,针阀开启第2阶段不再变化。更多还原

【Abstract】 The movement of needle valve in the common rail injector determines the injection and atomization effect directly. The movement rule of needle valve in the common rail injector is important to improve the structure of injector and the atomization effect. A high-pressure common rail injector simulation system was built,and a calculation model was established for optimizing the flow coefficients in two stages of cavitation and non-cavitation at the oil inlet and outlet holes of high pressure common rail injector and in the ball valve area. The movement characteristics of needle valve in the common rail injector are studied through theoretical analysis and experiments. The results show that the opening process of needle valve can be divided into two stages: slow opening stage and fast opening stage. Two opening stages of needle valve are due to the transfer of the throttled position. However,the needle valve is mainly influenced by the throttled position,so the closure of the needle valve is a single-stage. Rail pressure has an effect on the second fast opening stage,but not on the slow opening stage or the closing process. The o-pening process speeds up with the rise of the rail pressure. When the rail pressure reaches to a certain value,the fast opening stage of needle valve remains unchanged.更多还原