汽油机进气道参数化优化设计

Parametric Optimization Design for Gasoline Engine Intake Port

针对汽油机进气道性能对缸内空气流动影响较大、传统经验优化主观性强且效率较低的问题,提出了一种基于气道局部变形及旋转的参数化优化方法。采用控制点对进气道局部变形及整体旋转进行控制从而实现进气道变形的参数化,并采用粒子图像测速对该模型进行了验证。对各控制变量及优化目标进行实验设计及贡献度分析,识别出对流量系数及滚流比贡献度较大的控制变量。以提高流量系数及滚流比为目标,采用第二代非劣排序遗传算法对识别的控制变量进行多目标优化,根据寻优结果得到性能最优的进气道几何模型。结果表明:优化后的进气道在滚流比基本不变的情况下,流量系数由0.490变为0.526,提升了7.35%,优化效果较好。所提方法能够一次性得到接近理论帕累托前沿的最优解集,并根据需求选择最优的进气道几何模型,实用性较强且效率较高。

Aiming at the problem that the traditional experiential optimization for gasoline engine intake port is of strong subjectivity and low efficiency,a parametric optimization method for the intake port based on local deformation and rotation is proposed.According to the local deformation and rotation of the intake port controlled by control points,a parametric local deformation model of the intake port is established and validated by particle image velocimetry experiment.Then the design of experiments and contribution analysis are adopted to identify the control points making large contribution to the flow coefficient and tumble ratio.These control points are optimized to increase the flow coefficient and tumble ratio with the second generation non-dominated sorting genetic algorithm.The results show that from 0.490 to 0.526,the flow coefficient of the intake port remarkably rises by 7.35%with constant tumble ratio.The optimum solution sets close to theoretical Pareto front and the optimum intake port model can be obtained by this method with strong practicability and high efficiency.