缝隙区催化燃烧影响HCCI发动机燃烧与排放特性的多维数值模拟

Multidimensional Numerical Simulation of the Effect of Catalytic Combustion in Crevice Zone on the Characteristics of Combustion and Emissions of HCCI Engine

将发动机多维CFD程序KIVA-3V与化学动力学程序CHEMKINⅢ及DETCHEM相耦合,模拟了缝隙区催化燃烧对HCCI发动机燃烧及排放特性的影响.发动机以甲烷为燃料,其表面和空间采用详细的化学反应动力学机理.利用此模型分析了活塞顶部及侧面催化剂铂涂层对HCCI发动机着火时刻、缸内温度场及HC、CO、NO浓度场的影响.结果表明,当仅活塞顶存在催化剂涂层时,HCCI发动机着火时刻提前,HC、CO排放降低;当活塞顶及缝隙区同时存在催化剂时,HC、CO的排放更低,但NOx排放略有升高.

By coupling the KIVA-3V engine CFD package with the CHEMKIN Ⅲ and DETCHEM chemical kinetics packages, the effects of increvice catalytic combustion on combustion process and emissions of homogeneous charge compression ignition（HCCI） engine were simulated. Methane was used as fuel, and detailed surface and gas reaction mechanisms were adopted. Effects of catalytic combustion on ignition timing, temperature field and concentration field of HC, CO and NO of a HCCI engine, whose piston top and side surfaces had been coated with catalyst （platinum）, were discussed. The results show that when catalyst is applied on the piston top surface, ignition timing is advanced and HC and CO emissions are decreased. Under the same conditions, when catalyst is applied on both of the piston top and side surfaces, HC and CO emissions get lower, while NO, emissions slightly increase.