进气可变滚流系统应用于缸内直喷汽油机的数值模拟

摘要

建立了缸内直喷(GDI)汽油机三维数值模型,在分析原机工作过程的基础上引入了可变进气滚流系统(VITS).首先采用稳态CFD方法对两种方案进行了分析,进气可变滚流系统工作时气门最大升程的流量系数降低56％,滚流比提高221％.然后对该发动机进气、压缩和油气混合过程进行了瞬态CFD分析,结果显示,可变进气滚流系统工作时,在缸内能形成更规则的大尺度漩涡,与原机相比燃油蒸发速度更快,混合气均匀性更好,适用于GDI发动机均质燃烧模式.%The three-dimensional model of gasoline direct injection (GDI) engine was established. A variable intake tumble system (VITS) was introduced based on analyzing the working process of original engine. With the steady CFD method, two intake systems were compared. By the VITS, the flow coefficient of maximum valve lift decreased by 56% and the tumble ratio increased by 221 %. Then the intake, compression and mixing process were analyzed with the dynamic CFD method. The results show that the VITS can generate the more regular large-scale eddy. Its evaporation and mixing process are better than original intake system. The VITS is suitable for GDI homogeneous running mode.