催化型汽油机颗粒过滤捕集器催化剂设计与应用性能研究

基于某市售1.6L汽油缸内直喷(GDI)发动机轿车,进行底盘式汽油机颗粒过滤捕集器(GPF)/催化型汽油机颗粒过滤捕集器(CGPF)设计和性能研究,研究了不同涂覆量、涂覆工艺和贵金属含量设计对GPF/CGPF催化剂冷流背压、涂层形貌的影响,从而设计出低背压CGPF催化剂样品。通过对配备有国六标定系统的GDI汽油车进行系列全球统一轻型车测试循环(WLTC)工况排放试验,分别考察了加装底盘式GPF、CGPF及不同贵金属载量CGPF对尾气后处理排放的影响,并与采用原装紧密耦合式三效催化剂(TWC)时的排放性能进行对比分析。结果表明,加装GPF或CGPF配置,会对造成排气系统背压提升,但油耗变化不大;采用紧耦合式TWC+底盘式GPF/CGPF后处理集成净化系统,可有效解决单TWC布局下颗粒物数量(PN)超标问题;使用CGPF可在保证颗粒物捕集效果同时,较好发挥对气态污染物的处理作用,并使各个指标满足国六b排放要求;使用CGPF的催化剂后处理系统进行多次WLTC工况预处理运行,可有效提升其对颗粒物的捕集能力,使PN捕集效率从76.38%跃升至97.00%。

Study on Design and Application of a Catalyzed Gasoline Particulate Filter

The design and performance study of the underfloor GPF/CGPF catalyst were carried out based on a car with 1.6L GDI engine. The effects of different washcoat loading, coating process and precious metal content on the cold flow back-pressure, coating morphology of GPF/CGPF catalyst were studied, and then the lower back-pressure CGPF catalyst samples were prepared. Through a series of WLTC emission tests on the GDI engine vehicle with the China-6 calibration, the effects on the emission exhaust treatment with the underfloor GPF/ CGPF and different precious metal content were investigated, and then the emission performance of the original close coupled TWC were compared and analyzed. The results show that adding GPF or CGPF configuration will increase the back-pressure of the post-treatment system, but the oil consumption was not changed. The integrated purification system with close coupled TWC+ underfloor GPF/CGPF can effectively solve the problem of PN when using the single TWC layout. The use of CGPF can ensure the particulate matter captured and the gaseous pollutants cleared, meanwhile meets the China 6b emission requirements. The pre-treatment with several WLTC operating conditions can effectively improve the particulate matter capture capacity of CGPF catalyst system, and increase the PN filtration efficiency from 76.38% to 97%.