二冲程点燃式重油发动机爆震识别系统研究

发布时间：2018-04-15 02:29

本文选题：二冲程煤油发动机 + 爆震识别系统　；参考：《南京航空航天大学》2016年硕士论文

【摘要】：火花点燃式活塞发动机,特别是二冲程发动机,因机械结构简单、效率高、重量轻、升功率大等优点,在军事特种车辆和航空的中、小型无人直升机等领域有比较广泛的应用。与汽油相比,煤油蒸发较困难、闪点高,具有较好的使用安全性,易于运输;但其在燃烧时火焰传播的速度较低、抗爆性较差,而爆震是火花点燃式发动机上的一种非正常燃烧现象,严重时会影响其动力输出、增大燃油消耗,甚至发生发动机重要零部件损坏的现象。因此本文设计了二冲程煤油发动机爆震识别系统,并搭建了某型二冲程煤油发动机实验台架进行了实验研究。本文对机体振动信号的采集与分析方法进行了详细的叙述,并对发动机实验台架上采集到的发动机机体振动信号进行了分析处理,准确地提取出了信号的爆震中心频率等信息,设计了二冲程煤油发动机爆震识别系统,搭建了半物理仿真实验台对其功能进行了验证,并在试验台架上进行了实验研究,研究结果表明其功能和工作稳定性可以达到预期要求。主要工作如下:(1)研究了发动机爆震信号的采集与分析方法,通过对比三种主流的爆震信号检测及处理方法,本文以机体振动信号处理方法作为本文的研究方法,分析快速傅立叶变换算法与内禀模态特征能量法的优、缺点及其可行性,本文选取内禀模态特征能量法作为爆震信号特征提取的方法;(2)本文先对爆震识别系统的硬件进行了选型,并完成了硬件系统的设计;根据机体振动信号处理的过程及爆震状态、爆震强度的识别逻辑,进行了爆震识别系统的软件设计,并完成了编译、调试工作;自定义上位机与下位机的通讯协议,完成了上位机系统的设计,实现了实时反馈发动机的状态信息、爆震状态和爆震强度,并达到美观实用的效果。(3)搭建了半物理仿真实验台,对设计好的爆震识别系统进行了功能性验证,采用真实实验台架上采集到的机体振动信号作为输入信号,通过改变输入信号的频率和幅值的方式来验证爆震识别系统的功能。(4)搭建了二冲程煤油发动机实验台架,进行爆震识别系统的实验研究,测试其功能是否正常。实验研究结果表明二冲程煤油发动机爆震识别系统能够准确判断发动机的爆震状态并及时反馈爆震强度。
[Abstract]:Spark ignited piston engine, especially two-stroke engine, has been widely used in military special vehicle and aeronautical field because of its simple structure, high efficiency, light weight and large power.Compared with gasoline, kerosene is difficult to vaporize, has high flash point, has better safety in use and is easy to transport, but its flame propagation speed is lower and its anti-explosion property is poor during combustion.Detonation is an abnormal combustion phenomenon in spark ignited engine, which will affect its power output seriously, increase fuel consumption, and even cause damage to important parts of the engine.In this paper, a detonation identification system for a two stroke kerosene engine is designed, and an experimental bench for a two stroke kerosene engine is built.In this paper, the method of collecting and analyzing the vibration signal of the engine block is described in detail, and the vibration signal of the engine block collected on the engine experimental bench is analyzed and processed, and the frequency of the detonation center of the signal is extracted accurately.A detonation recognition system for two-stroke kerosene engine is designed. The function of the system is verified by a semi-physical simulation test bench, and the experimental research is carried out on the test bench.The results show that its function and working stability can meet the expected requirements.The main work is as follows: (1) the acquisition and analysis methods of engine detonation signals are studied. By comparing the three main methods of detection and processing of detonation signals, the vibration signal processing method of the airframe is used as the research method in this paper.The advantages, disadvantages and feasibility of fast Fourier transform algorithm and intrinsic mode characteristic energy method are analyzed.In this paper, the intrinsic mode characteristic energy method is selected as the feature extraction method of detonation signal.) in this paper, the hardware of the detonation recognition system is selected first, and the design of the hardware system is completed, according to the process of vibration signal processing and the state of detonation,The software design of the detonation recognition system is carried out, and the compiling and debugging work is completed, the communication protocol between the upper computer and the lower computer is defined, and the design of the upper computer system is completed.The real-time feedback of engine state information, detonation state and detonation intensity is realized, and the beautiful and practical effect is achieved. The semi-physical simulation experiment bench is built, and the functional verification of the designed detonation recognition system is carried out.A two-stroke kerosene engine test bench is built by changing the frequency and amplitude of the input signal to verify the function of the detonation recognition system by using the vibration signal collected on the real experimental bench as the input signal.The experimental study of knock recognition system was carried out, and the function of the system was tested.The experimental results show that the detonation recognition system of two-stroke kerosene engine can accurately judge the detonation state of the engine and feedback the detonation intensity in time.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK461

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