摘要本文主要是结合发动机工作时的热力学原理知识对发动机转矩的波动情况进行仿真 研究分析。首先介绍了最基本的热力学过程，结合发动机的工作原理分析了理想情况的 奥托循环，然后主要借助相关经验公式对发动机工作过程的不同阶段进行热力学分析， 建立了相关数学模型。之后对发动机工作时的主要运动件曲柄连杆机构进行运动学和动 力学分析，并结合发动机理想奥托循环将气缸内燃烧室压力作为主要驱动力从而建立曲 柄连杆机构的动力学模型，得到了发动机转矩的表达式。根据前面得到的相关数学表达 式，我们利用 MATLAB 进行仿真程序的编写及调试。通过运行程序我们得到了缸内压力 的变化情况和单个气缸转矩波动及四缸发动机总转矩波动的图像。在前面的基础上，我 们进一步研究改变进气压力，压缩比和活塞质量时对发动机转矩的波动的影响。在研究 改变进气压力和压缩比的环节中我们需要借助 P-V 示功图来确定缸内的峰值压力，所以 我们根据发动机工作时相关热力学微分方程编写 P-V 图的程序，联合之前发动机转矩波 动的程序，对仿真出的结果进行分析，寻找规律。69539

本次课题的目的主要是让我们结合所学的专业知识借助计算机仿真技术对发动机的 工作过程进行模拟仿真，研究发动机转矩波动的变化规律，体会计算机仿真技术研究发 动机过程的便利性，我们所得到的结果对于改善发动机的性能和对新型发动机的开发设 计具有一定的参考意义。

毕业论文关键词 发动机 曲柄连杆机构 仿真 热力学

毕 业 设 计 说 明 书 外 文 摘 要

Title Based on the thermodynamic model of engine torque ripple simulation research

Abstract

This paper is combined with the engine working knowledge of thermodynamics principle of engine torque fluctuations for simulation analysis. Firstly introduces the basic thermodynamic process, combining with the working principle of engine ideal otto cycle is analyzed, and then mainly with the help of related empirical formula of engine working process of the different phases of the thermodynamics analysis and related mathematical model is established. Then the main moving parts of engine work crank connecting rod mechanism kinematics and dynamics analysis, and combining the ideal otto cycle engine will chamber pressure in the cylinder as the main driving force to a dynamic model of connecting rod, engine torque expressions are obtained. According to the front of the relevant mathematical expressions, we use MATLAB simulation of writing and debugging. By running the program, we get the change of the pressure in cylinder and single cylinder four cylinder engine torque ripple and the total torque ripple of the image.In front of the basis, we further study the change of inlet pressure, compression ratio and quality of piston impact on motor torque fluctuation. On the study of the change of inlet pressure and compression ratio in we need to have the aid of P - V indicator diagram to determine the peak pressure inside the cylinder, so when we work according to engine related thermodynamic differential equation write P - V figure applications, joint program before the engine torque ripple, carries on the analysis, the results of the simulation of look for patterns. The purpose of this topic is primarily let us combine learning professional knowledge with the help of computer simulation technology, the working process of  engine  simulation,  studies  the  changing  rule  of  the  engine torque