电控液压可变气门机构性能及应用

Performances of Electro-Hydraulic Valve Train and Application

自主开发了一套电控液压驱动可变气门机构,并将该机构成功地应用于汽油可控自燃（CAI）试验系统.通过试验考察了不同驱动工作压力下和不同工作介质温度下电控液压驱动可变气门机构系统的可靠性与稳定性.研究发现,工作介质温度与压力对气门机构的开启、关闭性能存在影响,当工作在311~313 K气门的开启延时均值与标准差较小、而工作压力在7～9 MPa时最大气门升程波动较小.通过气门特性研究发现,电液气门的开启、关闭迅速,随着工作压力降低,气门开启速度与加速度减小,整个工作过程较为柔和.在气门试验的基础上,通过控制进、排气门定时变化,实现了燃烧室EGR策略、排气道EGR策略的CAI燃烧.

A new electro-hydraulic variable valve train（EHVVT）was developed and applied to gasoline CAI engine testing system.The effects of different working medium pressures and temperatures on the reliability and stability of EHVVT were investigated.Results indicate that pressure and temperature of working medium plays a key role in the characteristics of EHVVT opening and closing performance.When working medium temperature is between 311 K and 313 K,the mean and standard deviation of valve opening delay are small.The maximum valve lift fluctuation is small when working pressure is between 7 and 9 MPa.By studying the valve characteristic,EHVVT has fast response to the opening and closing.Based on EHVVT experiment,CAI combustion with combustion chamber EGR strategy and exhaust port EGR strategy is achieved through adjusting intake and exhaust valve timings.