柴油机螺旋气道数字化设计方法

通过系统分析柴油机螺旋气道几何结构以及气道敏感区域对气道流通性能的影响关系,确定了构建螺旋气道的关键结构参数。提出了一种以气缸盖结构为约束条件,涡流比为设计目标,再进行流量系数优化的螺旋气道数字化设计方法,建立了螺旋气道参数化数学模型,开发了一款柴油机螺旋气道数字化建模软件。针对一款自主开发的卧式两缸柴油机螺旋气道的设计要求,采用螺旋气道数字化建模软件建立了螺旋气道数字化三维模型,进行了模型光顺性分析和流通性能分析。分析结果表明,螺旋气道数字化设计方法具有一定的可行性和通用性,只需提供气缸盖结构、流通性能(涡流比和流量系数)的设计要求,通过该数字化设计方法和建模软件就能设计出满足要求的螺旋气道。

Digital Design Method of Helical Intake Port for Diesel Engine

The helical intake port geometry directly controls swirl ratio, volumetric efficiency and combustion characteristics as well as emissions reduction of diesel engine. A new digital design method of helical intake port was studied. In this method, cylinder head structure was considered as a constraint condition, and the swirl ratio was considered as the design target; then the flow coefficient was optimized. The effect of the geometry structure and port sensitive areas of diesel engine helical intake port on the intake port flow characteristics was analyzed, and several key structural parameters of helical intake port were defined. As a result, a parameterized mathematical model of helical intake port was established. Based on parameterized mathematical model of helical intake port and several key structural parameters of helical intake port, a digital modeling software about diesel engine helical intake port was developed. For the design requirements of helical intake port of self developed horizontal two cylinder diesel engine, a digital 3D model of helical intake port was established by using the helical intake port digital modeling software, and model smoothness and flow characteristics of this 3D model were analyzed. The results show that helical intake port digital design method has a certain feasibility and versatility. Just providing with the design requirements of the cylinder head structure and flow characteristics (swirl ratio and flow coefficient), a helical intake port that meets the requirements can be designed through using the digital design method and modeling software.