【摘要】 一种全可变液压气门机构(FHVVS)可实现气门最大升程、开启持续角和配气相位的连续可变.通过分析实测气门升程,发现FHVVS机构的进气门开启过程可分为凸轮驱动段、液压控制段和落座节流段.在液压控制段中气门开启不受凸轮型线的控制,使进气门的运行速度和加速度明显提高.与传统配气凸轮机构相比,在气门开启持续角相同时,FHVVS系统的气门开启角面值明显提高,且转速越低角面值提高幅度越大.试验表明:点燃式发动机采用FHVVS控制负荷,大幅度缩短了进气门开启时间,并在较短的进气门开启持续期内,提供了较大的气门开启角面值,使小负荷工况的泵气损失得到大幅度降低,尤其在小负荷、低转速时的改善幅度更为明显.更多还原

【Abstract】 By analyzing the valve lift curve measured on a fully hydraulic variable valve system(FHVVS),it is found that the intake valve opening process can be divided into cam drive section,hydraulic control section and seating section.In the hydraulic control section,the valve is not controlled by the cam profile,so the speed and acceleration of the intake valve are significantly improved.And the angular area value of the FHVVS under the same valve opening duration is obviously larger than that of the original valve mechanism.The experimental research shows that,when the FHVVS is adopted on a spark ignition(SI) engine to control the load,the intake valve opening time is greatly reduced and a larger angular area value is provided during the short intake valve opening duration.The pumping loss under low load conditions is greatly reduced,especially at low engine speeds.更多还原