催化燃烧对均质压燃发动机排放影响的数值模拟

Simulation of Influences of Catalytic Combustion on the Emissions of HCCI Engine

通过耦合DETCHEM软件包及CHEMKIN软件包中的SENKIN模块,对活塞顶涂有催化剂的均质压燃(HCCI)发动机的燃烧过程进行了数值计算,建立了多区模型.利用此模型分析了催化燃烧对HCCI发动机缸内温度、热释放速率以及未燃碳氢化合物(UHC)、氮氧化合物(NOx)、一氧化碳(CO)排放的影响,结果表明催化燃烧能降低UHC、CO的排放,但NOx的排放会有所升高.对不同催化剂及混合催化剂对HCCI发动机缸内温度、热释放速率以及UHC、NOx、CO排放的影响进行了探索,结果表明,和金属铂相比,以铑作催化剂时UHC的排放降低,但NOx、CO排放会有所升高;采用500/0Pt-500/0Rh的混合催化剂时,UHC、NOx的排放介于1000/0Pt与1000/0Rh之间,但CO的排放却比采用1000/0Pt与1000/0Rh时都要低.

By coupling the DETCHEM package and the SENKIN code of CHEMKIN chemical kinetics package, the combustion process of homogeneous charge compression ignition （HCCI） engine whose piston face had been coated with catalyst was simulated, and a multi-zone model was built. The influences of catalytic combustion on combustion temperature, heat release and UHC, NOx, CO emissions of the HCCI engine were analyzed by the multi-zone model. The results show that catalytic combustion can decrease UHC, CO emissions, but NO, emissions would rise. The influences of different catalysts and blended catalysts on combustion temperature, heat release and UHC, NOx, CO emissions of the HCCI engine were also explored. The results show that with Rh as catalyst, UHC emissions could be decreased, but NOx, CO emissions would rise Compared to Pt catalyzation. When using 50%Pt-50%Rh, UHC, NOx emissions would be between those under 100%Pt and 100%Rh, but CO emission would be lower than that under both 100%Pt and 100%Rh.