4气门直喷柴油机进气道组合和位置对进气涡流的影响

在稳流气道试验台上，对4气门直喷柴油机采用螺旋进气道和切向进气道的不同组合和不同相互位置时，气道的流动特性进行了试验研究。为了上邻气道的进气气流在缸内干涉的程度及其对缸内涡流运动的影响，提出了流量系数损失率和角动量矩损失率的概念。研究结果表明：柴油机采用切向气道在后的气道组合时，涡流比的变化受后面螺旋气道方位的影响较小，相邻气道的进气气流干涉较小。

Effects of Combination and Orientation of Intake Ports on Swirl in Four-Valve DI Diesel Engines

Flow coefficients and swirl ratios for different combinations and orientations of directed and helical intake ports were tested on a steady flow test rig.Two concepts respectively called loss rate of flow coefficient and loss rate of angular momentum were presented to analyze the interference of intake flow through two inlet ports.Experimental results show that greater interference of intake flow will be occurred when the directed intake port is upstream positioned,and the swirl ratio will be seriously affected by orientations of the directed port.When the helical intake port is upstream,interference of intake flow and effects of orientation of the helical port on swirl ratio will be less.