发动机废气再循环冷却器结构的改进研究

发动机废气再循环(EGR)技术能有效降低NOx有害排放，而EGR冷却器的采用将明显增强这一效果．优化冷却器的结构设计是提高冷却器效率的有效手段．通过对结构尺寸和散热面积基本相同的光管冷却器和翅片管冷却器的冷却效率进行对比试验研究，指出了原翅片管冷却器的不合理结构参数设计，并运用流体力学原理，分析了冷却器内部废气流动的状态，就翅片管冷却器进气口的长度、进气口截面形状、翅片的间隔距离等方面提出了结构的改进设计方案，试验结果表明，改进后的翅片管冷却器的冷却效率明显提高．

Investigation of exhaust gas recirculation coolers of DI diesel engine

Exhaust gas recirculation (EGR) technique can reduce NO_x emissions of DI diesel engines substantially. The potential reductions are especially significant in the case of cooled EGR and the efficiency of the EGR coolers is one of the most significant factors. Two EGR coolers were tested in order to determine their relative efficiencies. Based on test data, the improper construction designs are pointed out. By using the theory of fluid mechanics, the coolant flow characteristics are analyzed. The improved design of the flex-fin cooler is proposed by optimizing the length of intake port, the section profile of intake port and the distance between flex-fins. Based on analysis of test results, the modified design is proved to be of high efficiency.