【作者】 赵付舟；

【导师】 常思勤；

【作者基本信息】 南京理工大学 ， 车辆工程， 2010， 博士

【摘要】 增压系统是车用发动机中实现节能和环保目的的重要部件。针对车用发动机与涡轮增压器存在的稳态工况和瞬态工况匹配问题,涌现出越来越多的增压技术,包括旁通放气、涡轮流通面积调节、相继增压和混合涡轮增压等。混合涡轮增压技术是近年来备受发达国家青睐的一种能较好解决传统增压方案固有缺陷的新型技术,其原理是在涡轮增压器转轴上集成一个既能电动又能发电的高速电机,具有重要的研究价值。按照轻型车用增压柴油发动机的匹配要求,对增压发动机废气能量的定性分析可以得到增压系统废气能量分析模型。在废气能量分析模型基础上提出了混合涡轮增压系统控制模型。在这种控制模型中电机通过制动发电或电动驱动来及时调节增压系统的废气能量,从而改善增压发动机的特性。确定控制模型后就需要对混合增压系统的总体布置方案进行探讨,为建模分析与设计打下基础。模拟计算是发动机设计的有效工具,因此需要建立涡轮增压发动机数值模型。根据发动机边界条件和各个部件的热力学模型建立了废气旁通增压发动机计算模型,并通过试验检验数值模型的有效性。通过修改普通增压柴油机模型中的增压系统部分可以得到混合涡轮增压柴油机计算模型,并用于发动机稳态工况的仿真分析。利用模型计算得到了混合涡轮增压系统的能量调整策略,并对增压系统参数优化和排气提前角调整进行了研究。混合涡轮增压系统能量流的分析对合理分配增压系统能量份额和改善增压系统的性能具有重要意义。采用GRNN神经网络映射表明这种方法适合稳态工况下混合增压系统的映射预测控制。瞬态工况是增压发动机的一个重要研究领域,因此本文通过建立混合涡轮增压系统的瞬态模型仿真分析了增压系统关键参数调整对瞬态工况的影响,并采用模糊PID控制技术对混合涡轮增压系统模型进行控制效果仿真。仿真结果证实了本文进行的参数调整以及模糊PID控制都有利于混合增压系统瞬态特性的改善。在仿真计算确定主要结构参数后就可以对混合涡轮增压系统的零部件结构进行设计。把系统分为转子、轴承、密封、冷却水腔以及电机等几个部分,对各个部分分别进行详细设计,并最终设计出虚拟样机。对具体结构参数已经确定的混合涡轮增压系统,可以利用有限元分析方法对转子的临界转速振动情况进行计算。振动计算结果可以检验结构设计的合理性,并为试验台试验和装配发动机提供有用的数据。为了了解样机的性能,采用气动试验台作为试验装置对新研制的混合涡轮增压系统进行了各项试验,包括轴系振动试验、等压气机流量试验、机械效率试验、加速试验、热负荷试验以及烟度排放特性试验。试验初步证实了新设计的增压系统是可行的,为以后的工程推广提供了实践基础。更多还原

【Abstract】 Turbocharging system is a necessary accessory of vehicle engine for energy-saving and environmental protection.To solve the matching problem of steady and transient operating conditions between the turbochargers and the engines, many turbocharging technologies are emerging. These techniques include waste-gated turbocharging, variable geometry turbocharging, sequential turbocharging and hybrid turbocharging, etc. In recent years, hybrid turbocharging is a favored new technology in several developed countries, which can effectively solve the inherent shortcomings of traditional turbocharging. The hybrid turbocharging system consists of a turbocharger with a high speed electronic motor integrated into the turbocharger shaft, and an energy storage device. The project of hybrid turbocharging system has very important technical and economic research value.According to matching requirements of light vehicle diesel engine, the analysis model of exhaust gas energy is obtained through qualitative analysis of exhaust gas energy in turbocharged diesel engine. The control model of hybrid turbocharging system in steady engine condition is achieved on the basis of the analysis model. In this control model high speed motor can adjust the exhaust gas energy to improve the performance of engine by motor driving or braking. Then the overall layout of the system is examined, which can lay the foundation for simulation and design.Simulation is an effective means of engine design, therefore the numerical model of turbocharged engine is necessary to establish. The model of wastegated turbocharged diesel engine is set up by the boundary conditions and the thermodynamic models of various engine components, then experiments validate the rationality of numerical model.The numerical model of hybrid turbocharged diesel engine is obtained by modifying the turbocharging system of wastegated turbocharged diesel engine. Then the numerical model is used to simulate the steady condition of engine. The adjusting strategy for exhaust gas energy of hybrid turbocharged diesel engine can be obtained through simulation. The further research is carried out on parameter optimization of the turbocharging system and adjustment of the advanced exhaust angle. Analysis of energy flow is of great significance to properly distribute the energy share and improve the performance of the turbocharging system. Mapping with the GRNN neural network manifests that this method is appropriate to mapping control of hybrid turbocharging system in the steady condition of engine.Transient condition is an important area of research on turbocharged engine, so this dissertation establishes the transient model of hybrid turbocharging system, and analyzes the transient performance for hybrid turbocharging system about various parameters by simulation, then simulates the transient performance with fuzzy PID control. The simulation results confirm that the measures about the adjustment of parameters and fuzzy PID control can improve the transient characteristics of hybrid turbocharging system.The next research process is to design the component structure of hybrid turbocharging system when the main structural parameters have been determined by simulation. The system design is divided into the part of rotor, bearings, seals, cooling jacket and electrical motor, etc., and ultimately a virtual prototype has been designed. The calculation of the rotor vibration in critical speed can be performed by finite element analysis when the detailed parameters of the structure are determined. The calculation results of critical vibration can confirm that the structural design is reasonable, and will provide useful data for later test and engine matching.In order to obtain the performance of prototype, the newly developed hybrid turbocharging system is experimented in a pneumatic test bed. These experiments include the shaft vibration test, the compressor equal flow rate test, mechanical efficiency test, acceleration test, thermal load test and smoke emission test. Preliminary experiments confirm that the new design of the hybrid turbocharging system is feasible, and the experiments provide a practical basis for the future promotion of the project.更多还原