4气门汽油机缸内涡流的稳态测量研究

Studies on Steady Measurements of In-Cylinder Swirl in a 4-Valve Gasoline Engine

在稳流气道试验台上研究了 376四气门汽油机一进气门开、另一进气门全闭条件下的涡流特性。用热线热膜风速仪测量了不同气门升程、不同截面的缸内涡流场的分布情况。结果发现 :小升程时 ,缸内形成了大小不等、方向相反的 2个涡流 ,其作用相互抵消 ,缸内形成涡流的能力较小 ;大升程时 ,缸内形成了单一方向的涡流 ,缸内形成涡流的能力较大。同时发现缸内大尺度涡流旋转的中心并不完全与气缸轴线重合 ,在气缸上半部与轴线偏离较大 ,在下半部则较小 ,涡流轴线与气缸轴心线沿气缸自上而下趋于同心。

The characteristics of intake flow of a 4-valve gasoline engine head were studied on steady flow rig with one valve open and the other close.The distribution of in-cylinder swirl field at different planes was measured with hot wire anemometer (HWA) at different valve lifts.It was found that two vortexes with different values of swirl ratio were formed in the cylinder at low valve lifts.Due to the vortexes counteracting each other,the ability to generate swirl at low valve lifts was little.As single-direction swirl was formed in the cylinder at high valve lifts,so the ability to generate swirl was great.The swirl center did not coincide with the axis of cylinder exactly and deviated from the axis of cylinder larger at the upper semi-cylinder than at the lower one.It indicated that the core of swirl tended to be concentric from top to bottom of the cylinder.