【作者】 方清华；

【导师】 陈鹰； 陶国良；

【作者基本信息】 浙江大学 ， 机械电子工程， 2009， 博士

【摘要】 由于石油资源的日益短缺以及内燃机汽车造成的环境污染问题日益严重,世界各国汽车生产厂商和相关科研机构在致力于提高汽车内燃机性能以满足越来越严格的环保标准要求的同时,也把更多的目光投向新一代不使用石油等矿物质燃料、超低排放、清洁节能型汽车发动机的研发。本文设计了一种新型压缩空气/燃油混合动力发动机,其结构与现有的压缩空气/燃油混合动力发动机显著不同,这种新型混合动力发动机能够在同一台发动机上实现两种工作模式的运行:压缩空气动力模式和内燃机模式。压缩空气动力模式是将压缩空气的压力能转化为曲轴旋转的机械能,没有污染排放。内燃机模式的工作原理与普通四冲程内燃机相同,因此不可避免的也会产生有害排放物。尽管这种混合动力发动机不是零污染排放,但有害排放大大降低,属于低排放发动机。论文主要研究内容如下:第一章:根据压缩空气动力发动机的研究现状及存在的问题,引出了压缩空气/燃油混合动力发动机这一新型混合动力发动机的概念。在综述了压缩空气/燃油混合动力发动机的国内外研究现状和存在的问题之后,提出了本论文所要进行的主要研究工作。第二章:对压缩空气/燃油混合动力发动机进行了概念设计,设计了串联式和并联式两种结构形式的压缩空气/燃油混合动力发动机,并分别阐述了各自的工作原理和特点。根据热力学理想循环,对串联和并联式四冲程压缩空气/燃油混合动力发动机的可行性进行了分析研究,分析表明其两种工作模式的动力性能指标与非增压四冲程内燃机相近,能够满足小型汽车发动机的动力性要求。第三章:运用热力学第一定律和第二定律分别建立了四冲程压缩空气/燃油混合动力发动机两种工作模式的工作过程数学模型和工作过程可用能分析模型。根据建立的数值分析数学模型,设计了仿真计算方法,并确定应用定步长四阶龙格-库塔法求解数学模型的数值解。第四章:运用仿真计算方法对四冲程压缩空气/燃油混合动力发动机压缩空气动力模式的工作特性和工作过程可用能分布状况进行了研究。工作特性主要研究了速度特性以及配气相位、压缩空气进气压力、气缸容积、程径比等参数对工作特性的影响。工作过程可用能分布主要研究了气源压力、压缩空气进气压力以及进气温度等对系统能效的影响。第五章:运用仿真计算方法对四冲程压缩空气/燃油混合动力发动机内燃机模式的工作特性和工作过程可用能分布状况进行了研究,并对混合动力发动机两种工作模式的切换转速范围进行了分析。工作特性主要研究了速度特性和负荷特性。工作过程可用能分布主要研究了负荷和转速对系统能效的影响。第六章:设计了两种结构形式的并联式压缩空气/燃油混合动力发动机系统,搭建了混合动力发动机试验台架。根据二冲程气动发动机和四冲程内燃机的台架试验对四冲程压缩空气/燃油混合动力发动机两种工作模式的仿真结果进行了试验评估。制造了并联式二冲程压缩空气/燃油混合动力发动机并完成了台架试验,根据试验结果分析了两种工作模式的切换转速范围,验证了串/并联式压缩空气/燃油混合动力发动机结构原理的可行性。第七章:对全文进行总结并对后续研究工作进行了展望。更多还原

【Abstract】 Due to the increasing shortage of oil resources and increasingly serious environmental pollution problems caused by the internal combustion engine vehicles, automobile manufacturers and related research institutions not only strive to improve the performance of internal combustion engine to meet the increasingly stringent environmental protection standards, but also pay more attention to research and development of the new generation of alternative-fuel, ultra-low emission, fuel-saving automotive engines.In this paper, a new hybrid compressed-air and fuel engine concept is proposed, which can work by compressed-air powered engine mode and internal-combustion engine mode. The compressed-air powered engine mode is to change the pressure of compressed air into mechanical energy, and there are no pollutant emissions. The operating principle of internal-combustion engine mode is similar to the four-stroke internal combustion engine, so it will inevitably produce harmful emissions. Although the hybrid engine is not zero pollution emissions, fuel consumption and harmful emissions greatly reduce, belongs to low-emission and fuel-saving engine.The main research content of this paper is as follows:ChapterⅠ: After the introduction of the research situation and existing problems of the compressed air powered engine, a new hybrid compressed-air and fuel engine concept is put forward. Then give an overview of the domestic and foreign research situation and existing problems of hybrid compressed-air and fuel engine. Finally, the main research objects of this dissertation are proposed.ChapterⅡ: The series structure and the parallel structure of hybrid compressed-air and fuel engine are designed, and their operating principles and characteristic are respectively elaborated. According to the ideal thermodynamic cycle, the feasibilities of the series and parallel structure of hybrid four-stroke compressed-air and fuel engine are analyzed. The feasibility analysis shows that the performance indicators of the two working modes of hybrid four-stroke compressed-air and fuel engine are similar to those of non-supercharged four-stroke internal combustion engine, and can meet the small automobile engine’s needs. ChapterⅢ: By the first law of thermodynamics and the second law of thermodynamics, the working process mathematical model and the exergy analysis mathematical model of the two working modes of hybrid four-stroke compressed-air and fuel engine are respectively established. According to the established mathematical model, simulation and calculation method is designed and the fourth-order Runge-Kutta method is selected to solve the mathematical models.ChapterⅣ: The working characteristics and the exergy distribution of four-stroke compressed-air powered engine mode are researched using simulation computational method. Mainly study the speed characteristic and the influence of several key parameters such as valve timing, inlet air pressure of compressed air, cylinder volume, and stroke-bore ratio on the working characteristics. The influence of several key parameters such as pneumatic- source pressure, inlet-air pressure of compressed-air, and inlet-air temperature of compressed-air on the energy efficiency of the system is also analyzed.ChapterⅤ: The working characteristics and the exergy distribution of internal-combustion engine mode are researched using simulation computational method, and the speed scope to switch the two operating mode of the hybrid four-stroke compressed-air and fuel engine is also analyzed. Research of the working characteristics mainly includes the speed characteristics and load characteristics. Research of the exergy distribution mainly involves influence of speed and load on the energy efficiency of the system.ChapterⅥ: Two kinds of parallel hybrid compressed-air and fuel prototype engine are designed, and the test bench is also set up. According to the test results of two-stroke compressed-air powered engine and four-stroke internal-combustion engine, the simulation results of the two working mode of four-stroke hybrid compressed-air and fuel prototype engine are assessed. The bench test of parallel two-stroke hybrid compressed-air and fuel prototype engine is finished, and the switching rotation speed of the two working mode is analyzed.ChapterⅦ: The research work is summarized and perspectives on the future are presented.更多还原