摘要
对于轻型柴油机而言,采用可变喷嘴涡轮增压(VNT)技术和排气再循环(EGR)是较为理想的机内净化技术措施。国六轻型车排放法规的实施,使得高原地区轻型车的污染物排放问题受到更多的关注。为此,采用高原环境模拟装置,试验研究了在海拔分别为0、1000和1960 m时,基于VNT驱动高压EGR对一台轻型车用高速直喷柴油机燃烧和排放的影响。结果表明:采用VNT驱动EGR时,不同海拔下,在相同的VNT喷嘴环开度范围内,EGR率的变化范围几乎相同。不同海拔下,随着EGR率的升高,最高平均温度降低;最大转矩工况的最高缸内压力降低,燃烧始点推后,燃烧持续期延长;而额定功率工况的最高缸内压力升高,燃烧始点提前,燃烧持续期缩短。EGR仍然能够有效降低不同海拔下的NO_(x)排放,且随着海拔的升高,NO_(x)比排放降幅增大;不同海拔下,基于VNT驱动EGR时,随着EGR率的升高,最大转矩工况的CO比排放和烟度均升高,而额定功率工况的CO比排放和烟度均随之降低,并且高原地区,EGR对CO比排放和烟度的影响更为显著。
Variable nozzle turbocharging(VNT)technology and exhaust gas recirculation(EGR)are ideal technical measures to reduce in-cylinder emission for light-duty diesel engine.The implementation of China VI lightduty vehicle emission regulations has drawn more attention to the pollutant emission of light-duty vehicles in plateau areas.Therefore,the effect of EGR driven by VNT on combustion and emission performance of a light-duty highspeed direct injection diesel engine is experimentally studied at altitudes of 0,1000,and 1960 m by using a plateau environment simulation device.The results show that when EGR is driven by VNT,the variation range of EGR rate is almost the same within the same VNT nozzle opening range at different altitudes.As EGR rate increases,maximum mean temperature decreases at different altitudes.At the maximum torque condition,the peak cylinder pressure decreases,and the start of combustion is delayed,and combustion duration is prolonged,however,at the rated power condition,the peak cylinder pressure increases,the start of combustion is advanced,and combustion duration is shortened.EGR can still effectively reduce NO_(x)emissions at different altitudes,and the decreasing amplitude of brake specific NO_(x)emission increases as altitude increases.When driving EGR based on VNT at different altitudes,with the increase of EGR rate,brake specific CO emission and smoke both increase at the maximum torque condition,while brake specific CO emission and smoke both decrease accordingly at the rated power condition.Furthermore,EGR has a more significant effect on brake specific CO emission and smoke in plateau areas.
作者
王俊
申立中
毕玉华
雷基林
Wang Jun;Shen Lizhong;Bi Yuhua;Lei Jilin(School of Mechanical and Transportation,Southwest Forestry University,Kunming 650224;Kunming University of Science and Technology,Yunnan Province Key Laboratory of Internal Combustion Engines,Kunming 650500)
出处
《汽车工程》
EI
CSCD
北大核心
2022年第7期1088-1097,共10页
Automotive Engineering
基金
云南省教育厅科学研究基金项目(2018JS337)资助。
关键词
柴油机
海拔
可变喷嘴涡轮增压器
排气再循环
燃烧
排放
diesel engine
high altitude
variable nozzle turbocharger
exhaust gas recirculation
combustion
emission
作者简介
通信作者:王俊,副教授,博士,E-mail:zjwj1121@163.com。
