基于喷油器特征的缸内直喷汽油机混合气形成过程数值模拟

建立了多孔喷油器的一维仿真模型,对不同喷油压力下的喷油参数进行了计算,并详细分析了喷油器针阀开启和关闭时单孔喷雾锥角及喷孔出口有效流动面积的变化。以10 MPa喷油压力下的喷雾计算结果为边界,用FIRE软件模拟了定容喷雾并对其数值模型进行了标定,进而以一2.0 L涡轮增压缸内直喷汽油机为研究对象,分析了喷油时刻对缸内混合气形成的影响。结果显示,在5 000 r/min全负荷工况下,喷油时刻为400℃A时形成的混合气更能满足燃烧和发动机性能的要求。

Numerical Simulation of Mixture Formation Process for Gasoline Direct Injection Engine Based on the Injector Characteristics

With the ID simulation model of a multi-hole injector, the injection parameters at different pressure were calculated, the spray cone angle and efficient flow area at nozzle hole exit during needle opening and closing were also studied in detail. Based on the simulation results at 10 MPa, the spray formation was simulated by FIRE and validated in a constant volume bomb, furthermore, the influence of injection timing on mixture formation for a 2.0 L turboeharged gasoline director injection engine was analyzed. The resuh is, at full load and 5 000 r/min, the mixture would meet combustion and engine performance request preferably when injection is started at 400 ℃A.