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摘要发动机是汽车的心脏，研究发动机的动力学仿真有重大意义。就目前而言，试验研究仍是进行发动机动态性能和稳态性能研究的主要手段，但试验研究需要耗费大量的人力、财力。计算机仿真结果可以为后期的试验研究提供理论依据，大大减少发动机研发时间。 本文通过对某型四冲程汽油发动机的动力学过程进行数学建模，并通过MATLAB编程，建立了该型汽油发动机的动力学仿真模型，用于研究曲轴扭矩波动，并进行深入的参数化仿真研究。 （1） 通过深入了解发动机的工程热力学以及曲柄连杆机构的工作原理，简化机构并对发动机的内部压力变化进行理想化处理，建立了理想 Otto 循环数学模型、曲柄连杆机构的运动学数学模型和曲柄连杆机构的动力学数学模型。 （2） 基于建立的数学仿真模型，我们通过 MATLAB 进行编程，通过不断调试运行程序，建立了该汽油发动机的动力学仿真模型，并得到了缸内压力波动仿真结果、单缸发动机的曲轴扭矩仿真结果和四缸发动机扭矩波动的拟合结果。 （3） 通过已完成的仿真模型，我们进行深入的参数化研究。分别研究气缸内峰值压力的变化、活塞质量的变化、曲轴转速的波动对发动机扭矩波动的影响。最后还分析了飞轮对发动机扭矩波动的影响。 研究结果表明：气缸峰值压力、活塞质量的增大，结果会使得发动机最大扭矩波动的增大。然而转速的增大过程则有所不同，当发动机处于低转速和高转速时，最大扭矩波动相对较中转速波动来的大，同时飞轮起到了很好的稳定发动机扭矩输出的作用。 27368
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毕业论文关键词：发动机 Otto 循环 曲柄连杆机构 动力学 运动学 仿真
Title Engine dynamics modeling and simulation based on MATLAB Abstract The engine is the heart of the car, which is of great significance to study on Dynamic Simulation of engine. At present, the main means of experimental research is still as the engine dynamic performance and steady performance of the experimental research, but need to spend a lot of manpower and financial resources. Through the computer simulation can provide theoretical basis for experimental study of engine development, shorten the development cycle. We use the mechanical process of four stroke gasoline engine mathematical model and by the MATLAB programming and establish a dynamic simulation model of this type of engine, and further parametric simulation research. (1) By the principle of in-depth understanding of engine of engineering thermodynamics and the crank connecting rod mechanism and the engine internal pressure changes were idealized processing and establish mathematical model of the ideal Otto cycle mathematical model, crank connecting rod mechanism kinematics mathematical model and a crank link mechanism dynamics. (2) we based on the establishment of a mathematical simulation model and edit programing in MATLAB and by the way of continuous debugging program and cylinder pressure fluctuation simulation results and a single cylinder diesel engine crankshaft torque simulation results and four cylinder engine torque fluctuation of the fitting results are obtained (3) Through the engine simulation model, we studied the parameters deeply. We were used to study the variation of in cylinder peak pressure, changes in the quality of the piston, the crankshaft speed fluctuation of engine torque fluctuation. Finally, the influence of engine flywheel torque analysis. Research results show that the increase of the peak pressure and piston mass increases, the result will change the value of engine maximum torque . However increase in speed of the process is different, when the engine at low speed and high speed, the maximum torque fluctuations relatively fluctuation. Finally, due to the energy storage function of the engine under the condition of certain stable output torque. Keywords : Engine Otto cycle Crank and connecting rod mechanism Simulation Dynamics Kinematics