基于SCR技术路线的国Ⅳ柴油机开发

Development of Stage IV Emission Legislation Heavy-Duty Diesel Engine Based on SCR system

在一台国Ⅲ电控重型柴油机上进行了基于自主电控共轨燃油系统、自主选择性催化还原(SCR)技术的国Ⅳ柴油机开发,系统研究了燃油系统、进排气系统、SCR系统等对柴油机性能和排放的影响,研究结果表明:通过优化增压系统参数,采用高轨压和小孔径喷嘴,在爆压限值条件下调整喷油定时,柴油机比油耗和烟度较原机大幅改善,SCR喷射系统在当量比接近1时,NOx转换效率达到80%以上。循环测试结果表明:通过对燃烧系统和喷油控制参数的综合优化,并采用自主SCR系统,柴油机气体排放(NOx,HC和CO)和颗粒(PT)排放可以达到国IV排放标准要求,加权比油耗较原机大幅改善。

The stage IV emission legislation heavy-duty（HD） diesel engine was developed, which was based on the independent common rail fuel injection system and the independent SCR system. In the diesel engine, the influence on performance and emission by fuel supply system, intake and exhaust system and SCR system was researched. The results showed that after the parameters of turbo- charge system were optimized, and high common rail pressure and small diameter of nozzle were used, and fuel injection timing was adjusted based on cylinder pressure limitation, BSFC and soot emission was greatly improved. The NOx conversion efficiency exceeded over 80% when the SCR equivalence ratio was close to 1. The ESC test results showed that the stage IV emission legislation of the gas emissions （ NOx, HC and CO ） and particles （PT） emissions in the diesel engine can be achieved, and BSFC was greatly improved when the parameters of combustion system and fuel injection system were optimized and the independent SCR system was used.