EGR系统冷凝水析出问题仿真计算研究

Study on Influencing Factors of Condensate Precipitation in EGR System

随着节能减排要求的提高,各整车厂都在布局储备新技术,废气再循环技术(EGR)是降低有害污染物排放的有效措施。基于一款2.0 L的增压直喷汽油发动机,运用GT-SUITE计算仿真软件,分别从EGR率、相对湿度、EGR冷却器的冷却能力3个方面,研究了EGR系统中冷凝水析出影响因素。研究结果表明:EGR的最大使用比率受制于EGR冷却器的冷却能力;EGR率越高,进气温度越低,越容易析出冷凝水;相对湿度越大,越容易析出冷凝水;中冷器集成式进气总管,可以减小冷凝水对发动机总体性能产生的不利影响;增加冷却翅片数量,可以提高EGR冷却器冷却能力,减少冷凝水析出。

With the improvement of energy saving and emission reduction requirements,all vehicle manufacturers are laying out new technologies. EGR Technology is an effective measure to reduce the emission of harmful pollutants. Based on a 2. 0 L turbocharged direct injection gasoline engine,the influence factors of condensate precipitation in EGR system were studied from three aspects of EGR rate,relative humidity and EGR cooler capacity by using GT-SUITE simulation software. The results show that the maximum utilization ratio of EGR is limited by the capacity of EGR cooler;The higher the EGR rate is,the lower the intake air temperature is,and the easier the condensate is separated out;The higher the relative humidity is,the easier it is to precipitate condensate;The integrated intake manifold of intercooler can reduce the adverse effect of condensate on the overall performance of engine;Increasing the number of cooling fins can improve the cooling capacity of EGR cooler and reduce the precipitation of condensate.