电液连续可变气门液力挺柱部分设计原则分析

Analysis on the Design Principle of the Hydraulic Prop Part of the Electro-Hydraulic Continuous Variable Valve

液力挺柱部分设计不合理,会出现振荡次数过多、到达稳定状态时间过长、升程超调量过大等问题。为优化液力挺柱部分,通过构建液力挺柱部分的简化数学模型,利用Matlab软件,定性分析了其设计原则。得到的主要设计原则如下:1.液压活塞与气门的总质量(m)、气门弹簧刚度(k)、液力挺柱部分的阻尼(c)三个参数之间应满足0<c/(2√km)<1;2.m越小越好;3.在满足气门能够快速回位的前提下,k越小越好;4.c的取值则应同时考虑缩短调整时间(t_(■))并避免气门与发动机活塞相撞,最终得到c能够取值的最大与最小值。

If the hydraulic prop is not designed properly,the valve may oscillate too many times,take too long to reach the stable state,and suffer from an excessive overshoot in lift.In order to optimize the hydraulic prop section,a simplified mathematical model of hydraulic prop section is constructed and Matlab software is used to qualitatively analyze its design principles.The main design principles are as follows:1.The total mass of the hydraulic piston and the valve(m),the stiffness of the valve spring(k),and the damping of the hydraulic prop portion(c)should meet the relationship of 0<c/(2√km)<1.2.The smaller the m,the better;3.On the premise that the valve can return to position quickly,the smaller the k is,the better;4.The value of c should be taken into account to shorten the adjustment time(t_(■))and avoid the collision between the valve and the engine piston,so as to finally get the maximum and minimum value of c.