【作者】 陈述；

【导师】 侯献军；

【作者基本信息】 武汉理工大学 ， 动力机械及工程， 2014， 硕士

【摘要】 柴油机由于其高热效率和良好的燃油经济性得到了广泛应用，但其NOX排放量高，造成大气污染，危害人体健康。废气再循环技术（EGR）是目前公认的降低柴油机NOX排放污染物的有效手段之一。然而，EGR系统降低NOX的排放是以牺牲发动机的经济性和动力性为代价，为了兼顾发动机的经济和动力性能，无法单一追求高EGR率，而是应该优化EGR系统分布均匀性，同时通过柴油机喷油系统相关参数的优化来保证其经济和动力性能。本研究从柴油机机内净化技术着手，基于仿真技术和试验研究，进行了柴油机EGR系统的匹配与优化设计。首先，研究建立目标柴油机GT-power模型并进行燃烧模型校准，为EGR系统的匹配与优化提供入口边界条件。基于目标柴油机的NOX排放控制需求，为其设计EGR系统，基于三维流体分析软件Fluent进行EGR管路取气效率和进气歧管中的废气分布均匀性优化设计。其次，通过一维数值模拟软件GT-power按照十三工况法评估柴油机在匹配EGR系统后的动力性和经济性能。并通过台架试验获取柴油机在A100、B100、B75、C100四个排放高分担率工况的NOX排放、Soot排放和燃油消耗率数据。试验结果显示，通过调整各工况下的EGR率可以使柴油机NOX排放达到国Ⅳ标准，但是在进行EGR后，部分工况条件下的动力性和经济性有待提升。再次，实施柴油机喷油器硬件参数和喷油控制参数的优化措施来弥补EGR系统对柴油机动力性和经济性造成的损失。基于三维燃烧模拟软件KIVA分析DOE设计的不同目标参数的组合，得出各组合条件下的柴油机排放性能及经济性能。最后，通过分析仿真数据，获取四个目标工况点最优化的喷油器结构参数和喷油控制参数方案。给出使得目标柴油机NOX排放达到国Ⅳ标准的EGR方案和喷油器结构参数与控制参数，并通过GT-power模型验证了优化参数后的柴油机动力性能。计算结果显示，通过研究中一系列的设计与优化，柴油机可以在保证动力性与经济性的前提下满足NOX排放达到国Ⅳ标准。更多还原

【Abstract】 Due to high thermal efficiency and good fuel economy performance, the dieselengine has a wide application. But its emissions of NOXis high, resulting in airpollution and harm to human health.The EGR (Exhaust Gas Recirculation) techniqueis a kind of publicly recommended efficient method to control diesel engine NOXemission. But when the EGR deduct NOx,meanwhile it has a negative influence onengine power and fuel performance.Taking into consideration of both power and fuelperformance,cannot just raise EGR rate but to improve the distribution of EGR gasevenly,and optimize the related control parameters of the engine meanwhile. Thisresearch based on external purification measures and by means of simulation analysisand experimental method, completed EGR system matching and optimization design.Firstly, set up GT-power model of objective diesel engine and finishedcombustion model calibration, provided inlet boundary for CFD. Matched EGRsystem for the object diesel engine,based on Computational Fluid Dynamics(CFD)software analysed EGR system intake efficiency and distribution of exhaust gas inmanifold,thus gave a optimized proposal.Secondly, based on1-D simulation software GT-power calculated the power andfuel performance of the diesel engine according to ESC test cycle. Abttained theNOX、Soot and fuel consumption data under A100、B100、B75、C100workingcondition by bench test. The experiental data showed,by selecting a certain EGR ratefor each working condition,the diesel engine could reach the emission restrictionstandard.But under some working conditions,the power and fuel performance neededto improve.Thirdly,the research took some measures to make up the power and fuelperformance loss which coused by EGR system,such as optimization of fuel injectorhardware parameters and fuel control parameters.Based on3-D combustionsimulation software KIVA calculated different object parameter combination whichdesigned by DOE, obtained the emission and fuel-economy data.At last,by analyzing the simulation date to conclude a proposal of optimized fuel injector and control parameter combination which could enable the engine reachemission restriction. Put forward EGR solution and optimized parameter combinationof object diesel engine to reach the state four emission standard and meanwhileimprove its power and fuel-economy performance.更多还原