没有合适的资源?快使用搜索试试~ 我知道了~
资源推荐
资源详情
资源评论
I
摘要
随着我们国家更加富强,生活更加富裕,人们对汽车的要求也逐渐提高,
除了基本的代步,还要求汽车能够更加舒适、安静,且具有良好的声品质。所
以,汽车噪声的控制,特别是汽车排气噪声的控制,成为了汽车厂商们关注的
重点和焦点。汽车排气噪声的控制离不开汽车消声器的研究工作,文章的研究
就是围绕某汽车排气系统加速过程中噪声偏高和声品质较差的问题进行的。
在对排气噪声控制基础理论进行研究的基础上,文章给出了消声器优化中
涉及到的九种消声单元的传递矩阵。针对排气系统中存在的特殊结构凹孔板,
自行推导出了其传递矩阵公式。结合 MATLAB 的 GUI 模块,开发了汽车消声器
性能仿真系统。汽车消声器性能仿真系统不仅能够计算消声器的传递损失和压
力损失,也能播放测试噪声的音频,并计算其噪声值。同时,系统也能够完成
数据的输入、输出和相关数据的对比。
然后,文章通过汽车消声器性能仿真系统对优化工作中涉及到的六种消声
结构进行了声学特性的分析,并总结了各结构参数对消声性能变化的影响规律。
最后,文章借助汽车消声器性能仿真系统进行某汽车消声器的优化。根据
六种消声结构声学特性的分析结果,提出几种优化方案,通过系统计算其传递
损失并对比,择优确定最终的优化方案。经过尾管噪声数值和主观评价的仿真
验证及试验验证,确定优化方案符合要求,成功将排气系统的整体噪声水平降
低了 1.7dB(A)以上,并将 1200rpm 和 2000rpm 的噪声峰值降到了可接受的范围
内。经过本次优化工作,该汽车排气系统噪声在数值和声品质两个方面都得到
了较大改善。
文章在消声器的优化过程中,综合运用了噪声的客观评价和主观评价。分
析原排气系统性能时,通过噪声测试曲线和噪声测试音频,进行噪声的客观评
价和主观评价;优化方案尾管噪声仿真时,利用 GT-Power 生成噪声曲线和音频
进行噪声的客观评价和主观评价;试验验证时,针对试验车尾管噪声的数值和
音频,进行了噪声的客观评价和主观评价。进行消声器优化时,噪声客观评价
和主观评价综合运用,更加直观、实用,效果也更加突出。
关键词:MATLAB,消声器,优化,客观评价,主观评价
II
Abstract
At this stage, our country is more and more prosperous, and people are richer
and richer. As a result, people want to ask for more from vehicles. In addition to a
basic means of transportation, we need it to be more comfortable and quieter, and
have a good sound quality. Therefore, vehicle noise control, especially exhaust noise
control has become an emphasis and focus of vehicle manufacturers. Exhaust noise
control is inseparable from muffler research, and this paper’s research is made for that
a car’s noise is too high and the sound quality is poor in the process of acceleration.
After studying the basic theory of exhaust noise control, the paper analyses the
acoustic transfer matrixes of nine basic silencer units. For the plate with some
concave holes, its transfer matrix is calculated. A muffler performance simulation
system with GUI of MATLAB is built, and it not only can calculate the transmission
loss and pressure loss of a muffler, but also can play noise audio and calculate the
value of it. At the same time, the input and output of data can be completed by the
system, as well as the data comparison.
Then, by the vehicle muffler performance simulation system, the paper studies
the acoustic characteristics of six anechoic structures, which are used during the work
of muffler optimization, and summarizes the effects of various parameters to the
performance of the structures.
Finally, the paper optimizes a vehicle muffler by the system. According to the
acoustic characteristics of the common anechoic structure, several optimization
schemes are proposed, and the best one is selected by the comparison of transmission
losses, which are calculated by the system. After the simulation and experimental
validation of tailpipe noise’s numerical analysis and subjective evaluation, it
determines the optimization scheme is compliance with the requirements. The scheme
succeeds in reducing the overall noise level of exhaust system by at least 1.7 dB(A),
and the noise peaks at 1200rpm and 2000rpm down into an acceptable range. After
optimization, the vehicle exhaust noise is improved in both numerical value and
sound quality.
Objective evaluation and subjective evaluation work throughout the entire
III
process, when the paper performs the optimization of the muffler. As it analyzes the
performance of the original exhaust system, the paper performs objective evaluation
and subjective evaluation by analyzing the noise curve and audio gained from the test;
as it simulates the tailpipe noise, the paper makes objective evaluation and subjective
evaluation to the curve and audio of the noise, which is produced by GT-Power; as it
performs the experimental validation, objective evaluation and subjective evaluation
of the test noise are taken. In the process of muffler optimization, the integrated use
of objective evaluation and subjective evaluation has an intuitive, practical and
prominent effect.
Key words: MATLAB, muffler, optimization, objective evaluation, subjective
evaluation
IV
目录
第 1 章 绪论 ................................................................................................... 1
1.1 课题研究背景及意义 .............................................................................. 1
1.2 国内外研究现状 ...................................................................................... 2
1.3 本文主要研究内容 .................................................................................. 6
第 2 章 排气噪声控制基础 ....................................................................... 8
2.1 管道声学 .................................................................................................. 8
2.1.1 管道中声的反射 ............................................................................... 8
2.1.2 管道声阻抗 ..................................................................................... 10
2.2 传递矩阵法 ............................................................................................ 10
2.2.1 四端子网络 .................................................................................... 11
2.2.2 传递损失和压力损失的计算方法 ................................................ 11
2.3 汽车排气噪声 ........................................................................................ 13
2.3.1 汽车排气噪声的主要成分 ............................................................ 13
2.3.2 汽车排气噪声的影响因素 ............................................................ 14
2.4 排气消声器 .............................................................................................. 15
2.4.1 排气消声器的分类 ........................................................................ 15
2.4.2 排气消声器的性能评价方法 ........................................................ 17
2.5 本章小结 ................................................................................................ 19
第 3 章 汽车消声器性能仿真系统开发与应用 ................................ 20
3.1 基本消声单元的传递矩阵 .................................................................... 20
3.2 凹孔板传递矩阵的推导 ........................................................................ 24
3.3 声音文件处理基础 ................................................................................ 27
3.3.1 声音信号的分帧 ............................................................................ 27
3.3.2 短时傅里叶变换 ............................................................................ 29
3.4 汽车消声器性能仿真系统开发 ............................................................ 30
3.4.1 传递损失和压力损失计算 ............................................................ 31
3.4.2 噪声音频处理 ................................................................................ 34
3.4.3 系统优点 ........................................................................................ 34
3.5 案例计算验证 ........................................................................................ 35
V
3.5.1 传递损失计算验证 ........................................................................ 35
3.5.2 噪声音频处理功能验证 ................................................................ 37
3.6 本章小结 ................................................................................................ 38
第 4 章 六种消声结构的声学特性分析 .............................................. 39
4.1 扩张腔结构的消声特性 ........................................................................ 39
4.2 有内插管扩张腔结构的消声特性 ........................................................ 40
4.3 穿孔管共振结构的消声特性 ................................................................ 41
4.3.1 共振管容积对穿孔管共振结构消声特性的影响 ........................ 41
4.3.2 穿孔率对穿孔管共振结构消声特性的影响 ................................ 42
4.3.3 小孔直径对穿孔管共振结构消声特性的影响 ............................ 43
4.4 穿孔板结构的消声特性 ........................................................................ 44
4.4.1 穿孔率对穿孔板结构消声特性的影响 ........................................ 44
4.4.2 小孔直径对穿孔板结构消声特性的影响 .................................... 45
4.5 穿孔扩张管结构的消声特性 ................................................................ 45
4.5.1 穿孔率对穿孔扩张管结构消声特性的影响 ................................ 46
4.5.2 小孔直径对穿孔扩张管结构消声特性的影响 ............................ 47
4.6 凹孔板结构的消声特性 ........................................................................ 47
4.6.1 凹孔数量对凹孔板结构消声特性的影响 .................................... 48
4.6.2 凹孔面积对凹孔板结构消声特性的影响 .................................... 48
4.7 本章小结 ................................................................................................ 49
第 5 章 某汽车消声器优化设计研究 ................................................... 50
5.1 某汽车原消声器性能分析 .................................................................... 50
5.1.1 原消声器噪声测试分析 ................................................................ 50
5.1.2 原消声器的结构分析 .................................................................... 53
5.1.3 原消声器性能仿真分析 ................................................................ 54
5.2 排气消声器优化设计 ............................................................................ 55
5.2.1 副消声器优化 ................................................................................ 55
5.2.2 主消声器优化 ................................................................................ 58
5.3 优化方案的仿真验证 ............................................................................ 61
5.4 试验验证 ................................................................................................ 64
5.5 本章小结 ................................................................................................ 66
剩余80页未读,继续阅读
资源评论
2201_75761617
- 粉丝: 20
- 资源: 7339
上传资源 快速赚钱
- 我的内容管理 展开
- 我的资源 快来上传第一个资源
- 我的收益 登录查看自己的收益
- 我的积分 登录查看自己的积分
- 我的C币 登录后查看C币余额
- 我的收藏
- 我的下载
- 下载帮助
安全验证
文档复制为VIP权益,开通VIP直接复制
信息提交成功