进/排气边界对高原柴油机缸内制动的数值模拟  

Numerical Simulation of the Effect of Intake and Exhaust Boundary on the In-Cylinder Braking of a Plateau Diesel Engine

作　　者：刘海军[1,2] 侯献军 Liu Haijun;Hou Xianjun(Hubei Key Laboratory of Advanced Technology for Automotive Components,Wuhan University of Technology,Wuhan 430070,China;School of Mechanical and Traffic Engineering,Ordos Institute of Technology,Ordos 017010,China)

机构地区：[1]武汉理工大学现代汽车零部件技术湖北省重点实验室,湖北武汉430070 [2]鄂尔多斯应用技术学院机械与交通系,内蒙古鄂尔多斯017010

出　　处：《内燃机学报》2021年第5期409-416,共8页Transactions of Csice

基　　金：国家重点研发计划资助项目(2018YFB0106401);鄂尔多斯应用技术学院重点资助项目(KYZD2020004)。

摘　　要：基于单级增压柴油机构建一维热力学仿真模型,模拟了柴油机排气边界参数及不同增压系统的变海拔(0、2和4 km)缸内工作特性及制动功率.结果表明:在压缩上止点前,随着排气门开启持续期的增加,总平均指示压力、平均有效压力及制动功率先升高后略微降低;随着排气门开启时刻的推迟,总平均指示压力、泵气损失压力及平均有效压力先升高后略微降低;在压缩上止点存在最优的开启持续期及开启时刻,使得柴油机制动功率最大.相对单级增压系统,在海拔为0、2和4 km标定转速下,两级增压系统最大总平均指示压力分别提升65%、74%和55%,最大平均有效压力分别提升64%、68%和45%.相对原机(无缸内制动),单级及两级增压系统在海拔为0 km标定转速下,其制动功率分别增加112%、249%;在海拔为4 km时单级及两级增压系统制动功率分别增加164%、238%.A 1D thermodynamics model was built based on a single-stage turbocharged diesel engine.Exhaust boundary parameters,in-cylinder working characteristics and the braking power of the diesel engine were simulated and studied under different altitude of 0,2 and 4 km with different supercharging systems.The results show that,before the compression top dead center,with the increasing of exhaust valve opening duration,IMEP360(gross indicated mean effective pressure),brake mean effective pressure(BMEP)and the in-cylinder braking power firstly increase and then decrease slightly.With the delaying of exhaust valve opening time before the compression top dead center,the IMEP360,pumping mean effective pressure(PMEP)and BMEP firstly increase and then decrease slightly.Hence,there is an optimal exhaust valve opening time and duration to obtain the maximum braking power.In addition,compared to the single-stage turbocharging system,the two-stage turbocharging sys-tem at the rated engine speed increases the maximum IMEP by 65%,74%,55%and the maximum BMEP by 64%,68%,45%at the altitudes of 0,2 and 4 km,respectively.Compared to the original engine with no incylinder braking,the single-stage turbocharger and the two-stage turbocharger increase the braking power at the rated engine speed by 112%and 249%at the altitude of 0 km,respectively.While at 4 km altitude,the braking power of the single-stage and two-stage turbochargers increases by 164%and 238%respectively.

关 键 词：高原柴油机 缸内制动 不同增压系统 制动功率 

分 类 号：TK422[动力工程及工程热物理—动力机械及工程]