4气门汽油机缸内空气运动的试验研究

Experimental Study of Air Flow in Cylinder of a 4-Valve Spark Ignition Engine

使用激光多普勒测速仪(LDA)在发动机倒拖工况下测量了一台4气门Fox350汽油机缸内的空气运动.试验结果显示,在靠近缸盖底平面附近,单气门独立工作与双气门同时工作有不同的流场形态.缸内的空气运动增加了涡流分量,总体表现为滚流和涡流合成的斜轴涡流.

The incylinder air bulk flow is a mainly tumble motion for fourvalve gasoline engine. However, this tumble affection and valid engine power output can be decreased when the engine is operated at light load and low speed because of the slow intake flow and unfavourable evaporation and atmosphere. Closing one of the two valves during the engine is operated at light load and lower speed is also an effective method to deal with the variation of engine speed operation. In this paper,air flow in the cylinder was measured by laser doppler anemometry(LDA) on a motored 4valve Fox350 spark ignition engine.The experimental results show that the incylinder air bulk motion produces an oblique swirl near the bottom of cylinder head in a 4valve Fox350 spark ignition engine when one of the two valves of the dualinlet configuration is closed. The incylinder air bulk motion is the combined motion of tumble and swirl.