摘要自从 19 世纪第一台内燃机问世之后，内燃机的发展日新月异。人们利用其实现了前 所未有的技术革新。飞机，汽车，潜艇等等形状各异功能不同的工具成为现实。而自由 活塞发动机作为内燃机的一部分，研究其放热率对于燃油燃烧性能的改善意义重大。而 这也符合可持续发展的理念，因此本文对于自由活塞发动机燃烧过程分析的浅显研究也 有其意义。

本文在传统内燃机基础上对自由活塞发动机进行工作过程和燃烧过程分析之后，利 用示功图来计算其燃烧放热率。首先对由示功图所得数据进行光顺处理，消除曲线的随 机震荡。再利用能量守恒方程，质量守恒方程及理想气体状态方程三个基本方程建立燃 烧放热率的数学计算模型。再通过 MATLAB 编写其程序，运用程序计算得到燃烧放热率。 最后应用韦伯函数对其结果进行拟合，得到了燃烧持续时间和燃烧品质系数这两个描述 发动机重要的参数。69540

毕业论文关键词 自由活塞发动机 示功图 燃烧放热率 韦伯函数

毕 业 设 计 说 明 书 外 文 摘 要

Title The Analysis of Free-piston Engine’s Combustion Process Based on Indicator Diagram.

Abstract

Since the 19th century, with the first internal combustion engine apperaed, the internal combustion engine quickly developed. People use it to achieve an unprecedented technological innovation. Planes, cars, submarines and so shapes the function of different tools to become a reality. The free-piston engine as part of an internal combustion engine, the heat release rate study for improving fuel combustion performance is significant. This is also consistent with the concept of sustainable development, this paper analyzes the research process for shallow free-piston engine combustion has its significance.

In this paper, based on the indicator diagram of free piston engine combustion process analysis, first for the data from the indicator diagram for smoothing processing, eliminate random oscillation curve. Recycled energy conservation equation, mass conservation equation and three basic equation of ideal gas state equation to establish the mathematical calculation model of combustion heat release rate. Through MATLAB program, using the program to calculate the combustion heat release rate. Finally use wiebe function to fit the result to get the two described the engine combustion quality coefficient of important parameters, combustion duration and the form factor.

Keywords Free Piston Engine Indicator Diagram Heat Release Rate Wiebe Function

本科毕业设计说明书 第 I 页

目 次

1 引言 1

1.1 本课题的研究目的与意义 1

1.2 国内外的研究和发展现状 1

1.3 本文技术路线与主要内容 3

2 自由活塞发动机工作过程分析及数学模型建立 5

2.1 自由活塞发动机概述 5

2.2 建模的基本假设 6

2.3 缸内工作过程分析及热力学建模 7

2.4 计算中的具体问题