凸轮驱动式液压可变气门机构设计及运动特性  

Design and Motion Characteristics of Cam-driven Hydraulic Variable Valve Mechanism

作　　者：解方喜[1,2] 钟兵[1,2] 杨国志 赵平 洪伟 苏岩[1,2] Xie Fangxi;Zhong Bing;Yang Guozhi;Zhao Ping;Hong Wei;Su Yan(Jilin University,State Key Laboratory of Automobile Simulation and Control,Changchun 130025;College of Automotive Engineering,Jilin University,Changchun 130025;FAW Foundry Co.,Ltd.,Changchun 130062)

机构地区：[1]吉林大学,汽车仿真与控制国家重点实验室,长春130025 [2]吉林大学汽车工程学院,长春130025 [3]一汽铸造有限公司,长春130062

出　　处：《汽车工程》2020年第3期307-314,共8页Automotive Engineering

基　　金：国家自然科学基金(51876079);吉林省科技发展计划项目(20180201008GX,20170101137JC);吉林省教育厅“十三五”科学研究项目(JJKH20180141KJ)资助。

摘　　要：降低汽油机部分负荷泵气损失需要灵活的可变气门机构,凸轮驱动式液压可变气门具有较好的应用前景,但依然面临压力波动和气门落座速度难以控制等问题。本文中通过调节节流阀开度使0~4 800 r·min^-1的气门升程在0~8.2 mm范围内连续可变,仿真探究了活塞直径对压力波动和节流孔径对气门落座速度的影响,并据此确定了活塞直径和节流孔径,试验研究了液压油温度对气门运动特性和气门落座速度的影响规律。研究发现:适当增大活塞直径能降低系统工作压力并减小压缩波峰值,有利于降低压力波动,最终选取挺柱和气门活塞直径分别为17和14.5 mm,小于1.6 mm的节流孔径可使4 000 r·min^-1时的气门落座速度小于0.5 m·s^-1。转速不变,气门最大升程随节流阀开度的增大而逐渐降低;相同节流阀开度,转速越高气门最大升程越大,节流阀开度越大,不同转速时的最大升程差异也更大。节流阀全关,液压油温度对升程的影响很小;相同节流阀开度,随液压油温度升高,气门腔压力和气门最大升程逐渐降低。气门落座速度对液压油温度不敏感,不同温度的气门落座速度方差仅为4.9%。Reducing the pumping loss of gasoline engine at part load needs flexible variable valve mechanism. Cam-driven hydraulic variable valve has good engineering application prospects, but it also faces the problems of pressure fluctuation and difficult control of valve seating velocity(VSV). In this paper, the valve lift of 0~4 800 r·min^-1 is continuously changed in the range of 0~8.2 mm by adjusting the throttle valve opening(TVO). The influence of piston diameter on pressure fluctuation and throttle aperture on valve seating velocity is simulated, with the piston diameter and throttle aperture confirmed, and the effect of hydraulic oil temperature on valve motion characteristics and VSV are studied experimentally. The results show that an appropriate increase of piston diameter can reduce the system working pressure and the compression wave peak, which helps reduce pressure fluctuation, and finally the chosen diameter of tappet and valve piston is 17 and 14.5 mm respectively. The throttle aperture of less than 1.6 mm can make valve seating velocity of 4 000 r·min^-1 less than 0.5 m·s^-1. The maximum valve lift decreases gradually with the increase of throttle valve opening under the same speed;with the same TVO, the higher the motored speed, the larger the valve maximum lift and the greater the TVO, the larger the difference of maximum lift at different speeds. Hydraulic oil temperature has little effect on the lift with the throttle valve closed;under the same TVO, the valve chamber pressure and maximum valve lift decrease gradually with the increase of hydraulic oil temperature. The valve seating velocity is insensitive to hydraulic oil temperature, with a variance of only 4.9% at different temperatures.

关 键 词：液压可变气门机构 气门运动特性 压力波动 气门落座速度 液压油温度 

分 类 号：U464.171[机械工程—车辆工程]