可变喷嘴涡轮增压器(VNT)对高原地区车用柴油机性能与排放的影响研究  

Influences of Variable Nozzle Turbocharger (VNT) on Performance and Emission of Vehicle Diesel Engine operating at High Altitude

作　　者：杨永忠[1,2] 申立中[1] 毕玉华[1] 雷基林[1] 王俊[1] 

机构地区：[1]昆明理工大学云南省内燃机重点实验室,昆明650500 [2]昆明云内动力股份有限公司,昆明650000

出　　处：《装备环境工程》2017年第10期12-18,共7页Equipment Environmental Engineering

基　　金：国家自然科学基金项目(51466003;51666005)

摘　　要：目的系统研究可变喷嘴涡轮增压器(VNT)对运行在高原地区的车用柴油机动力性、经济性以及排放性能的影响关系,为高原地区电控柴油机与VNT的匹配控制以及降低其污染物排放提供一定的理论指导。方法在海拔高度约为1960 m的高原地区,选取柴油机的典型运行工况,即低速1400 r/min全负荷、2200 r/min全负荷(最大转矩工况)以及4000 r/min全负荷(额定功率工况),通过试验研究VNT对柴油机性能与排放的影响。结果在低速工况,随着VNT喷嘴环开度的增大,动力性降低,经济性恶化;在最大转矩与额定功率工况,均存在一个最佳的VNT喷嘴环开度使得转矩最大,同时油耗最低。随着VNT喷嘴环开度的增大,进气流量、空燃比、中冷前压力、中冷前温度以及涡前压力均降低,而涡前温度升高。在三个典型运行工况下,随着VNT喷嘴环开度的增大,氮氧化物(NO_x)比排放逐渐降低,而烟度、一氧化碳(CO)以及碳氢(HC)比排放逐渐升高,VNT对HC排放的影响较小。结论在高原地区,通过减小VNT喷嘴环开度可以降低涡前温度,进而降低柴油机的热负荷,提高其可靠性,合理调节VNT喷嘴环开度可以获得较为满意的NO_x比排放与烟度排放。mObjective To have systematic study on the influences of variable nozzle turbocharger （VNT） on the power, economy and emission performance of a vehicle diesel engine running in plateau area and to provide some theoretical guidance for the matching control of the electronic control diesel engine with VNT as well as reducing the pollutant emission of the diesel engine operating at high altitude. Methods The effect of VNT on diesel engine performance and emissions was researched by experiment at an altitude of about 1960m and at the typical operating conditions, such as low engine speed 1400 r/min full load, 2200r/m in full load （peak torque condition） and 4000 r/min full load （rated power condition）. Results At low engine speed condition, with the increase of VNT nozzle opening, the power declined and the economy deteriorated. There was an optimal VNT nozzle opening which made the torque reach the peak value and the brake specific fuel consumption have the lowest value at peak torque condition and rated power condition respectively. With the increase of VNT nozzle opening, intake air mass flow rate, air-to-fuel ratio, compressor outlet gas pressure, compressor outlet gas temperature and turbine inlet gas pressure decreased; while the turbine inlet gas temperature in-creased. Brake specific nitrogen oxides （NOx） emission decreased gradually and smoke, brake specific carbon monoxide （CO） emission and brake specific hydrocarbon （HC） emission increased gradually along with the increase of VNT nozzle opening at these three typical operating conditions. In addition, VNT had little effect on HC emission. Conclusion In plateau regions, the turbine inlet gas temperature can be reduced by closing the VNT nozzle opening so as to decrease the thermal load of diesel engine and improve its reliability. Satisfactory brake specific NOx emission and smoke emission can be obtained by means of adjusting VNT nozzle opening reasonably.

关 键 词：柴油机 高原 可变喷嘴涡轮增压器 比排放 

分 类 号：TJ07[兵器科学与技术—兵器发射理论与技术] TG147[一般工业技术—材料科学与工程]