电液驱动可变气门机构性能试验及应用

基于电液驱动可变气门机构,设计了负气门重叠配气策略,并研究了其对汽油压缩着火(GCI)燃烧性能的影响。通过研究电磁阀输入信号对气门正时的影响,发现气门正时随电磁阀输入信号线性变化,在此基础上设计了负气门重叠控制策略。进一步地,在发动机着火状态下,验证气门升程曲线的可重复性,结果表明排气门升程波动比进气门略大,其最大波动幅值为0.2 mm,最大标准差为0.056 mm,重复性较好,满足使用要求。同时,随着气门开启持续期的减小,气门升程出现小幅降低。在上述基础上,研究了进、排气门正时对GCI燃烧性能的影响,其中排气门关闭时刻对内部EGR率的改变影响较大,对GCI燃烧性能的影响占主导作用。

Performance Test and Application of Electro-Hydraulic Variable Valve Train

Based on electro-hydraulic variable valve train,the negative valve overlap(NVO)strategy was designed and the effect of NVO strategy on gasoline compression ignition(GCI)was studied.By studying the influence of solenoid valve input signal on valve timing,the valve timing was found to change linearly with the solenoid valve input signal and the negative valve overlap strategy was designed.In addition,the repeatability of valve lift curve was verified under the engine ignition condition. The results showed that the fluctuation of exhaust valve lift was slightly larger than that of the intake valve.The maximum fluctuation amplitude of exhaust valve lift was 0.2 mm,its maximum standard deviation was 0.056 mm,and so the repeatability was good enough to meet the requirements.Further,the valve lift slightly decreased with the decrease of valve opening dura-tion.In the end,the influences of intake and exhaust valve timing on the combustion performance of GCI were studied.It was found that the exhaust valve close timing had a great influence on internal EGR rate and a dominant effect on GCI combustion performance.