可变二级增压柴油机变海拔工作特性数值模拟
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摘要
以两级增压共轨重型柴油机为研究机型,采用GT-Power构建了其一维热力学仿真模型,对比可变二级增压(RTST)柴油机随高压级可变截面涡轮增压器(VGT)在不同叶片开度(20%~100%,)及不同海拔(0~4,km)下的工作特性.结果表明:不同转速工况下,空燃比和泵气损失随VGT叶片开度和海拔高度增加而降低.不同海拔下,随VGT叶片开度增大,低速时转矩与有效热效率先升高、后降低,高速时显著增大.随叶片开度和海拔增加,NO_x排放降低,soot排放大幅升高.海拔为4,km时,叶片开度从20%,增至100%,,低、高速工况的转矩和有效热效率均分别增加7.5%,和39.2%,,NO_x排放分别降低38%,和24%,;海拔为2,km时,不同转速工况下柴油机匹配RTST均能实现较高的EGR率(超过60%,).VGT叶片开度减小,EGR率快速增大,转矩及有效热效率降低,有效燃油消耗率(BSFC)逐渐增加,NO_x排放快速降低,soot排放先升高后降低.在EGR率约为35%,时,RTST柴油机综合性能达到最佳.
Based on the calibrated one-dimensional thermodynamic simulation model constructed by GT-power,the comparative study on performance of a common-rail heavy-duty diesel engine equipped with regulated two stage turbocharging(RTST)systems was conducted at different altitudes(0—4,km).Results show that,at different speed conditions,the air-fuel ratio and pumping loss of the engine decrease with the increase of the VGT blade opening and the altitude.At different altitudes,the torque and the break thermal efficiency increase with the increase of VGT opening under low speed,and increase significantly under high speed.With the increase of blade opening and altitude,NO_x decreases and soot increases rapidly.At altitude of 4,km,both the torque and the brake thermal efficiency under low and high speed working conditions increase by 7.5%, and 39.2%, respectively,and the specific emission of NO_x decreases by 38%, and 24%, respectively when the VGT blade opening increases from 20%, to 100%,.At different speed conditions,the diesel engine equipped with RTST can achieve a higher EGR rate(more than 60%,)at altitude of 2,km.With the decrease of the blade opening,the EGR rate increases rapidly and the torque and the brake thermal efficiency decrease.While the BSFC increases,the specific NO_x emission decreases rapidly,and the specific soot emission increases first and then decreases.When EGR rate is within 35%,,the comprehensive performance of the RTST diesel engine reaches the best point.
Based on the calibrated one-dimensional thermodynamic simulation model constructed by GT-power,the comparative study on performance of a common-rail heavy-duty diesel engine equipped with regulated two stage turbocharging(RTST)systems was conducted at different altitudes(0—4,km).Results show that,at different speed conditions,the air-fuel ratio and pumping loss of the engine decrease with the increase of the VGT blade opening and the altitude.At different altitudes,the torque and the break thermal efficiency increase with the increase of VGT opening under low speed,and increase significantly under high speed.With the increase of blade opening and altitude,NO_x decreases and soot increases rapidly.At altitude of 4,km,both the torque and the brake thermal efficiency under low and high speed working conditions increase by 7.5%, and 39.2%, respectively,and the specific emission of NO_x decreases by 38%, and 24%, respectively when the VGT blade opening increases from 20%, to 100%,.At different speed conditions,the diesel engine equipped with RTST can achieve a higher EGR rate(more than 60%,)at altitude of 2,km.With the decrease of the blade opening,the EGR rate increases rapidly and the torque and the brake thermal efficiency decrease.While the BSFC increases,the specific NO_x emission decreases rapidly,and the specific soot emission increases first and then decreases.When EGR rate is within 35%,,the comprehensive performance of the RTST diesel engine reaches the best point.
引文
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[13]陈贵升,马帅营,毛斌,等.基于EGR技术的低排放重型柴油机燃烧系统开发[J].内燃机学报,2013,31(4):309-317.
[14]陈贵升,狄磊,苏娜,等.基于不同增压系统共轨柴油机变海拔工作特性模拟[J].内燃机学报,2016,34(6):504-512.
[15]刘瑞林.柴油机高原环境适应性研究[M].北京:北京理工大学出版社,2013:173-176.
[16]Yousefzadeh A,Jahanian O.Using detailed chemical kinetics 3D-CFD model to investigate combustion phase of a CNG-HCCI engine according to control strategy requirements[J].Energy Conversion and Management,2017,133:524-534.
[2]Stürzebecher C,Re?J,Bohn C,et al.A diesel engine model including exhaust flap,intake throttle,LP-EGR and VGT.Part II:Identification and validation[J].IFAC-Papers On Line,2015,48(15):60-65.
[3]Leek V,Ekberg K,Eriksson L.Development and usage of a continuously differentiable heavy duty diesel engine model equipped with VGT and EGR[C]//SAE Paper.Detroit,Michigan,USA,2017,2017-01-0611.
[4]Breitbach H,Metz D,Weiske S,et al.Application and design of the electrically driven compressor from Borg Warner[J].MTZ Worldwide,2015,76(10):16-21.
[5]Gandhi N G,Aghav Y,Gokhale N,et al.Scientific approach of calculating deration factor for a turbocharged after cooled diesel engine[C]//SAE Paper.Maharashtra,India,2015,2015-26-0039.
[6]Penhalbel L T B,Moreira F B,Araújo J P D.Altitude and winter tests for best vehicle operations[C]//SAE Brasil 2007 Congress and Exhibit.Sao Paulo,Brazil,2007,2007-01-2522.
[7]Liu R,Zhang Z,Dong S,et al.High-altitude matching characteristic of regulated two-stage turbocharger with diesel engine[J].Journal of Engineering for Gas Turbines and Power,2017,139(9):094501.
[8]董素荣,刘瑞林,周广猛,等.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[J].内燃机学报,2017,35(3):231-237.
[9]赵长禄,李长江,韩恺,等.不同海拔下柴油机可调二级增压系统的经济性调节方法[J].农业机械学报,2016,47(2):369-376.
[10]Meng X.Research of turbo-supercharging system based on power recovery of diesel engine at plateau[C]//SAE Paper.Rosemont,IL,USA,2016,2016-01-8087.
[11]Yang M,Gu Y,Deng K,et al.Analysis on altitude adaptability of turbocharging systems for a heavy-duty diesel engine[J].Applied Thermal Engineering,2018,128:1196-1207.
[12]Yang M,Gu Y,Deng K,et al.Influence of altitude on two-stage turbocharging system in a heavy-duty diesel engine based on analysis of available flow energy[J].Applied Thermal Engineering,2018,129:12-21.
[13]陈贵升,马帅营,毛斌,等.基于EGR技术的低排放重型柴油机燃烧系统开发[J].内燃机学报,2013,31(4):309-317.
[14]陈贵升,狄磊,苏娜,等.基于不同增压系统共轨柴油机变海拔工作特性模拟[J].内燃机学报,2016,34(6):504-512.
[15]刘瑞林.柴油机高原环境适应性研究[M].北京:北京理工大学出版社,2013:173-176.
[16]Yousefzadeh A,Jahanian O.Using detailed chemical kinetics 3D-CFD model to investigate combustion phase of a CNG-HCCI engine according to control strategy requirements[J].Energy Conversion and Management,2017,133:524-534.