平面阀流动特性分析

Investigation of Flow Characteristics Over Plane Control Valve in Common Rail Injector

控制阀是高压共轨系统中最重要的执行零件,其流动特性对喷油器性能影响很大,以某平面型控制阀为研究对象,使用计算流体力学(CFD)方法研究了平面阀的流动特性,并分析了喷油器回油背压对喷油稳定性的影响规律,计算结果表明:在衔铁小升程时,平面阀底面及阀座顶部平面更容易受到高速燃油的冲刷,随着衔铁升程的增加,平面阀处空穴强度及范围逐渐增加,衔铁升程小于最大升程0.72倍时,进油量孔和平面阀处起主要的节流作用,衔铁升程大于最大升程0.72倍后,进油量孔和出油量孔将起主要的节流作用,空穴导致的平面阀发生随机性的旋转,是导致喷油稳定性变差的原因,增加回油背压可使空穴减小,从而使喷油稳定性提高。

Control valve is the most important component in the common rail system,its flow characteristics strongly affect the performance of the injector. In this paper,a plane control valve is studied through CFD and the relationship between injection stability and pressure of oil return line is analyzed. The results show: when the armature lift is small,the bottom of the plane valve and the top of seat seem to be scoured easily,and with the increasing of the armature lift,the range and intensity of cavitations are increased gradually. What's more,when the armature lift is less than 0. 72 of the maximun lift,inlet orifice and plane valve play a major role for throttling. The armature lift is greater than 0. 72 of the maximun lift,inlet orifice and outlet orifice will play a major role for throttling. Besides that,the plane valve rotate stochastically result from the cavitations,which is harmful to the injection stability,and increasing the back pressure will decrease the cavitations,which is the key factor to increase stability.