【作者】 王伟涛；

【导师】 李国岫；

【作者基本信息】 北京交通大学 ， 动力机械及工程， 2008， 硕士

【摘要】 柴油机进气系统的结构和流动性能的优劣将直接影响柴油机的动力性、经济性和排放特性。而且,提高柴油机功率的关键之一是在换气过程中提高充量系数并降低进气系统的流动阻力。设计和匹配最佳的柴油机进气系统,就能在柴油机一定的转速范围内增加进气量,提高功率,改善扭矩特性,降低油耗率和烟度。因此,研究并改进气系统的性能及结构无论是在理论上还是在实践中都很有必要。本论文首先应用发动机一维模拟软件GT-POWER建立了增压柴油机进气系统工作过程计算模型,仿真计算结果与实验结果吻合良好。并在此基础上进行了该柴油机标定工况的工作过程仿真计算,对其标定工况下的主要性能指标进行了预测分析。之后对进气管路进行了优化。进气管参数主要包括进气总管管长和管径、稳压腔容积和进气歧管的管长、管径。通过分析不同进气管参数对管内压力波动、充气效率的影响,总结出规律,并找出主要影响因素。并应用GT-POWER自带的优化工具建立了以标定工况下柴油机容积效率最优为目标的增压柴油机性能优化的仿真模型,计算结果表明:经过参数优化后,该柴油机进气能力得到加强,进气均匀性有所提高。最后,通过对增压器、中冷器与增压柴油机的匹配研究,确定排气系统采用脉冲增压系统。在该系统的基础上,建立了该柴油机与增压系统的联合运行线,并进行了柴油机外特性分析,仿真结果显示柴油机与增压器匹配较好;以降低中冷器阻力为优化目标,确定了中冷器主要结构参数,这为以后的中冷器设计提供了的帮助。更多还原

【Abstract】 Intake system of diesel engine on structure and flow characteristics directly influence power, fuel economy and emission performance of diesel engine. One key to raising power of diesel engine is improving volumetric efficiency and lower resistance to the flow of intake system in air exchange process. And, design and matching the best diesel engine intake system, we can increase the intake flow rate, improve power, improve torque characteristics and lower fuel consumption rate and soot in a certain speed. So, in theory and in practice, it is necessary to research and improve on both performance and structure of intake system.The thesis based on software GT-POWER is applied for establishing the calculation model of turbocharged diesel engine intake system. The calculation can be accord with the experiment result accurately. On the basis of model, the simulation of rated condition is conducted, and main performance is predicted. After, the intake pipe has been optimized. The parameters of intake pipe include the length of main pipe and its diameter, length and diameter of manifold and volume of steady-pressure box. From the analysis of intake parameter’s effect on pressure fluctuation and volumetric efficiency, we made a conclusion and found the main affected facts. After confirming constraint and parameters, an optimization model aim to obtain maximum volumetric efficiency in rated condition is set up. The computation results indicate that the intake uniformity is satisfying.The end, it is determined that the exhaust system uses the pulse turbocharged system via matching supercharger, intercooler and turbocharged diesel engine. Based on the system, the combination operating curve variable geometry turbocharger and diesel engine is established, and external characteristics of diesel engine are analyzed. Simulation results showed that diesel engine supercharger match better. The major structural parameters of intercooler are determined aim to reduce the resistance of intercooler. This provides help for design of intercooler.更多还原