CN101655057B - Muffler of double-section expansion chamber of automobile - Google Patents

Abstract

The invention relates to a muffler of a double-section expansion chamber for developing induction noise of an automobile, which can provide a wider anechoic frequency range. The invention adopts the technical scheme that the muffler of the double-section expansion chamber of the automobile is provided with an expansion chamber and is characterized in that the expansion chamber comprises a left expansion chamber and a right expansion chamber; an inlet and an outlet of each expansion chamber are both provided with inserting pipes, wherein the inlet of the left expansion chamber and the outlet of the right expansion chamber share one inserting pipe.

Description

Muffler of double-section expansion chamber of automobile

Technical field

The present invention relates to a kind of automotive air intake noise exploitation muffler of double-section expansion chamber.

Background technique

What generally use in the automotive air intake system is reactive muffler.When the principle of reactive muffler was sound wave process silencing apparatus, acoustic impedance changed, and a part of acoustic energy is reflected back toward sound source, made to transmit the acoustic energy minimizing.Reactive muffler is to be combined by the pipe of abrupt interface and chamber, and the cell of each band pipe all has the natural frequency of oneself.When the sound wave that includes various frequency contents enters first short tube, only near the sound wave of some frequency first mesh natural frequency could arrive second short tube mouth by mesh, the sound wave of other frequency then can not can only come back reflective by mesh in cell.

As shown in Figure 1, the expansion chamber silencing apparatus is the most general a kind of in the reactive muffler, and its acoustic attenuation performance depends primarily on divergence ratio m (expansion chamber sectional area S ₂With air-flow path sectional area S ₁Ratio) and the length l of expansion chamber.

The transmission loss of single-unit expansion chamber silencing apparatus is calculated and is generally obtained by formula (1).

$\mathrm{TL}=10\lg [1+\frac{1}{4}{(m-\frac{1}{m})}^2{\sin }^2\mathrm{kl}]\mathrm{dB}---\left(1\right)$

In the formula: TL--transmission loss, dB;

The m--divergence ratio, $m=\frac{S_2}{S_1};$

The k--wave number, $k=\frac{2\mathrm{\π}}{\mathrm{\λ}}=\frac{2\mathrm{\πf}}{c}=\frac{\mathrm{\ω}}{c},$ The suitable different frequency value of different value of K;

The length of l--expansion chamber silencing apparatus.

From formula (1) as can be seen transmission loss TL be the periodic function of kl, work as sin ²Transmission loss maximum during kl=1, at this moment, $\mathrm{kl}=\frac{\mathrm{\π}}{2}$ $l=\frac{\mathrm{\λ}}{4}$ Promptly when l equals 1/4 wavelength or its odd-multiple, the transmission loss maximum.

This up-to-date style (1) can be rewritten as:

$\mathrm{TL}=10\lg [1+\frac{1}{4}{(m-\frac{1}{m})}^2]\mathrm{dB}---\left(2\right)$

Can be analyzed by top formula and to draw: design expansion chamber silencing apparatus must the choose reasonable divergence ratio and the length of expansion chamber.

The major defect of single-unit expansion chamber silencing apparatus is to exist manyly by frequencies, and promptly when l=1/2 wavelength or its integral multiple, transmission loss is zero, in order to eliminate the frequency of passing through that these do not eliminate the noise, as shown in Figure 2, generally adopts the way of interpolation pipe.At the tubule that appropriate length is inserted in the import and the outlet of expansion chamber respectively, just can correspondingly eliminate some and pass through frequency.Is l if enter pipe in the length of anechoic room _a, the length of output tube in silencing apparatus is l _b, the transmission loss formula of this silencing apparatus is:

$\mathrm{TL}=10\lg [1+\frac{1}{4}{(m-\frac{1}{m})}^2{\left(\frac{\sin \mathrm{kl}}{\cos k{l}_a\cos k{l}_b}\right)}^2]\mathrm{dB}---\left(3\right)$

This shows, it is 1/2l and two tubules of 1/4l that length is inserted in the import of expansion chamber and outlet port respectively, can make the sound wave of propagating forward run into the phase places that the different interfaces of pipe and reflected sound wave differ 180 degree, makes both amplitudes equal, phase place is opposite, interferes mutually.When inserting the 1/2l inner connecting tube, the odd-multiple that can eliminate 1/2 wavelength is by frequency, and when inserting the 1/4l inner connecting tube, the even-multiple that can eliminate 1/2 wavelength passes through frequency.If both are comprehensive, just can obtain not acoustic attenuation performance in theory by frequency.

Summary of the invention

The object of the invention is to provide a kind of automotive air intake noise exploitation to use muffler of double-section expansion chamber, and wideer frequency of noise elimination scope can be provided.

Realize the object of the invention technological scheme:

A kind of automotive air intake noise exploitation muffler of double-section expansion chamber, has expansion chamber, it is characterized in that: expansion chamber by about two the joint expansion chamber constitute, the import and the outlet of every joint expansion chamber are equipped with insertion tube, wherein left expansion chamber import and right expansion chamber export shared same insertion tube.

l ₁=2l ₂, l wherein ₁Be the length of left expansion chamber, l ₂Length for right expansion chamber.

l ₃=1/2l ₁, l ₄=1/2l ₂, l ₂=l ₃=2 l ₄=2 l ₅=4 l ₆, l wherein ₃For left expansion chamber import insertion tube is positioned at the length of expansion chamber, l ₄For left expansion chamber exports the length that insertion tube is positioned at expansion chamber, l ₅For right expansion chamber import insertion tube is positioned at the length of expansion chamber, l ₆Be positioned at the length of expansion chamber for right expansion chamber outlet insertion tube.

Double-section expansion chamber integral body is rectangular shape, and the cross section is a square.

Each insertion tube caliber of corresponding expansion chamber import, outlet is identical.

l ₁Be 400mm.

Each insertion tube caliber of corresponding expansion chamber import, outlet is 65mm.

The length of side of expansion chamber square sectional is 400mm.

The beneficial effect that the present invention has:

The present invention adopts muffler of double-section expansion chamber, and by the effective configuration to each parameter, provides wideer frequency of noise elimination scope.

Definition according to transmission loss can transform the stack that the transmission loss that obtains this muffler of double-section expansion chamber is exactly the transmission loss of two single-unit expansion chamber silencing apparatuss, i.e. the transmission loss of muffler of double-section expansion chamber is:

$\mathrm{TL}=10\lg [1+\frac{1}{4}{(m-\frac{1}{m})}^2{\left(\frac{\sin k{l}_1}{\cos {\mathrm{kl}}_3\cos {\mathrm{kl}}_4}\right)}^2+10\lg [1+\frac{1}{4}{(m-\frac{1}{m})}^2{\left(\frac{\sin {\mathrm{kl}}_2}{\cos {\mathrm{kl}}_5\cos {\mathrm{kl}}_6}\right)}^2]$

$=10\lg [1+\frac{1}{4}{(m-\frac{1}{m})}^2{\left(\frac{\sin 8k{l}_6}{\cos {4l}_6\cos {2\mathrm{kl}}_6}\right)}^2+10\lg [1+\frac{1}{4}{(m-\frac{1}{m})}^2{\left(\frac{\sin {4\mathrm{kl}}_6}{\cos {2\mathrm{kl}}_6\cos {\mathrm{kl}}_6}\right)}^2]--\left(4\right)$

This shows that the transmission loss of muffler of double-section expansion chamber is big, and the frequency of noise elimination scope is widened greatly.Simultaneously, double-section expansion chamber integral body of the present invention is rectangular shape, and the cross section is a square, more helps the layout of silencing apparatus.

Description of drawings

Fig. 1 is existing single-unit expansion chamber acoustic wave filter structure schematic representation;

Fig. 2 is existing band inner connecting tube single-unit expansion chamber acoustic wave filter structure schematic representation;

Fig. 3 is a structural representation of the present invention;

Fig. 4 is transmission loss of the present invention and frequency relation figure.

Embodiment

As shown in Figure 3, expansion chamber by about two the joint expansion chamber 1,2 constitute, the import and the outlet of every joint expansion chamber are equipped with insertion tube, wherein left expansion chamber import and right expansion chamber export shared same insertion tube 3.Double-section expansion chamber integral body is rectangular shape, and the cross section is a square.The positive central opening in expansion chamber cross section, each insertion tube caliber of corresponding expansion chamber import, outlet is identical.

l ₁=2l ₂, l wherein ₁Be the length of left expansion chamber 1, l ₂Length for right expansion chamber 2.

l ₃=1/2l ₁, l ₄=1/2l ₂, l ₂=l ₃=2 l ₄=2 l ₅=4 l ₆, l wherein ₃For left expansion chamber import insertion tube is positioned at the length of expansion chamber, l ₄For left expansion chamber exports the length that insertion tube is positioned at expansion chamber, l ₅For right expansion chamber import insertion tube is positioned at the length of expansion chamber, l ₆Be positioned at the length of expansion chamber for right expansion chamber outlet insertion tube.

Each parameter of muffler design is as follows:

l ₁＝2l ₂＝400mm，l ₃＝200mm，l ₄＝l ₅＝l00mm，l ₆＝50mm。

The length of side of expansion chamber square sectional is 400mm, and the sectional area of expansion chamber is designed to: S ₂=400 * 400mm ²

The diameter of turnover pipe is designed to: d=65mm;

So air-flow path sectional area: $S_1=\frac{\mathrm{\π}}{4}{d}^2=\frac{3.14\×{65}^2}{4}{\mathrm{mm}}^2$

The divergence ratio of expansion chamber: $m=\frac{S_2}{S_1}=\frac{400\×400\×4}{3.14\×65\×65}=48.24$

Parameter of the present invention is updated in the aforementioned formula (4),, then can calculates the transmission loss of this silencing apparatus under different frequency if get airspeed c=340m/s.As shown in Figure 4, the present invention has bigger transmission loss in all frequencies, can well be used for the exploitation of gas handling system noise.

Claims (6)

1. an induction noise exploitation is used muffler of double-section expansion chamber of automobile, has expansion chamber, it is characterized in that: expansion chamber by about two joint expansion chamber constitute, the import and the outlet of every joint expansion chamber are equipped with insertion tube, outlet of wherein left expansion chamber and the shared same insertion tube of right expansion chamber import;

l ₁=2l ₂, l wherein ₁Be the length of left expansion chamber, l ₂Length for right expansion chamber;

l ₃=1/2l ₁, l ₄=1/2l ₂, l ₂=l ₃=2l ₄=2l ₅=4l ₆, l wherein ₃For left expansion chamber import insertion tube is positioned at the length of left expansion chamber, l ₄For left expansion chamber exports the length that insertion tube is positioned at left expansion chamber, l ₅For right expansion chamber import insertion tube is positioned at the length of right expansion chamber, l ₆Be positioned at the length of right expansion chamber for right expansion chamber outlet insertion tube.

2. muffler of double-section expansion chamber of automobile according to claim 1 is characterized in that: double-section expansion chamber integral body is rectangular shape, and the cross section is a square.

3. muffler of double-section expansion chamber of automobile according to claim 2 is characterized in that: each insertion tube caliber of corresponding expansion chamber import, outlet is identical.

4. muffler of double-section expansion chamber of automobile according to claim 3 is characterized in that: l ₁Be 400mm.

5. muffler of double-section expansion chamber of automobile according to claim 4 is characterized in that: each insertion tube caliber of corresponding expansion chamber import, outlet is 65mm.

6. muffler of double-section expansion chamber of automobile according to claim 5 is characterized in that: the length of side of expansion chamber square sectional is 400mm.

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