多缸汽油机全可变液压气门系统的开发与试验研究

Development and Experimental Research on Fully Hydraulic Variable Valve System for Multi-Cylinder Gasoline Engines

提出了一种适用于4缸汽油机的全可变液压气门系统,通过凸轮驱动和液压传动使进气门开启,通过开启控油阀使进气门回落,通过调节控油阀的泄油时刻改变进气门的最大升程和开启持续角。建立了气门运动规律测量试验台架,并对全可变液压气门系统的气门升程进行了试验测量。试验结果表明:该系统可实现最大气门升程在0到最大设计升程之间连续可变,进气门开启持续角在曲轴转角0°~284°之间连续可变。进一步研究表明:全可变液压气门系统按汽油机标定转速5 000r/min高速运行时,在不同气门升程下均未出现气门运动规律的"失真"现象,说明该系统能够满足汽油机高速运行的需求。试验还发现多缸机液压气门机构存在相互干涉问题,通过改进设计控油阀结构,消除了由此导致的气门异常开启现象。

A fully variable hydraulic valve system （FVHVS） for four-cylinder gasoline engines was introduced. In the system, an intake valve was opened by hydraulic oil which was driven by its cam, and seated by the opening of its rotatory control valve, and both its maximum lift and opening duration were governed by the opening timing of its rotatory control valve. All intake valve lifts of the system were measured in a motored valve train test bench. The experimental results show that the maximum valve lift of an intake valve can be continuously varied from 0 to 9. 2 mm and the opening duration from 0° to 284° in crank angle. Furthermore, any distortion is not observed in all valve lift curves at the rated engine speed of 5 000 r/min, which means that the FVHVS can meet the demand of high-speed gasoline engines. Moreover, an abnormal opening of intake valve due to mutual interference in a multi-cylinder FVHVS was observed and eliminated by improving the design of rotatory control valves.