VGT叶片开度对二级增压柴油机高海拔燃烧特性与性能的影响  

Effects of VGT Blade Opening on Combustion and Performance on a Two-Stage Turbocharging Diesel Engine at High Altitude

作　　者：董素荣 刘瑞林 周广猛 刘卓学 熊春友[2] 刘鹏宇[2] 

机构地区：[1]军事交通学院军用车辆系,天津300161 [2]军事交通学院研究生管理大队,天津300161

出　　处：《内燃机学报》2017年第3期231-237,共7页Transactions of Csice

基　　金：国防预研资助项目(40407030103)

摘　　要：通过可调二级增压柴油机高海拔燃烧与性能模拟试验,研究了不同海拔条件下二级增压器与柴油机的匹配特性、柴油机燃烧特性和动力经济性能随可调二级增压系统调节参数(VGT叶片开度)的变化规律.结果表明:不同海拔下,可变截面的涡轮增压器(VGT)叶片开度对高压级增压器特性参数(涡前压力、压比和转速)影响较大,而对低压级增压器特性参数影响较小;随VGT叶片开度减小,柴油机进气流量增大,联合运行线向阻塞线方向移动,缸内最高燃烧压力和最高瞬时放热率增大,预混燃烧瞬时放热率峰值减小,滞燃期缩短,燃烧重心向上止点方向偏移;海拔为5.5,km、VGT叶片开度从80%降低到50%,有效功率提高了2.5%,有效热效率提高了2.4%.Through the high altitude simulation test of combustion and performance on an adjustable two-stage turbo- charging diesel engine, the effects of the variable geometry turbocharger （VGT） blade opening on the turbocharger matching performance, combustion characteristics, power output and fuel consumption were researched. The results show that at different altitudes, the VGT blade opening as a significant effect on turbo characteristic parameters （the pressure before turbine, the ratio of boost pressure, the turbocharger speed） for the high pressure turbocharging section, while it has a little impact on the characteristics for the low pressure turbocharging section. With the decrease of the VGT blade opening, the intake flow of the diesel engine increases, the combined operation points of the two- stage turbocharger and the diesel engine move to the flow blocking curve. Meanwhile, the maximum combustion pressure and the peak of heat release rate increase, but the peak of the heat release rate in the premixed combustion stage and the period of auto-ignition delay decrease. Also, the crank angle of 50% accumulated heat release moves to the top dead center（TDC）. Subsequently, the brake power and the brake thermal efficiency increase by 2.5% and 2.4% respectively when the VGT blade opening decreases from 80% to 50% at the altitude of 5.5 km.

关 键 词：柴油机 高海拔 可调二级增压系统 燃烧特性 性能 

分 类 号：TK421.2[动力工程及工程热物理—动力机械及工程]