CN212643886U - Silencer for automobile fuel evaporation pipe - Google Patents

Abstract

The utility model provides a muffler for car fuel evaporating pipe, it including: an upper housing and a lower housing. The outer side of the upper shell is connected with a first connecting module with two through ends, the inner side of the upper shell is connected with a first inner tube with two through ends, and one end of the first inner tube is communicated with one end of the first connecting module. The outer of the lower shell is connected with a second connecting module with two through ends, the inner of the lower shell is connected with a second inner tube with two through ends, one end of the second inner tube is communicated with one end of the second connecting module, and the upper shell and the lower shell are connected with each other to form an expansion cavity. The problem that the sound silencing effect of the silencer on certain frequencies is zero can be solved by arranging the first inner pipe and the second inner pipe in the expansion cavity of the silencer.

Description

Silencer for automobile fuel evaporation pipe

Technical Field

The utility model relates to a muffler for car fuel evaporating pipe.

Background

In order to reduce the emission of automobiles, China stipulates that a fuel evaporative emission control system (EVAP) must be installed on newly-shipped automobiles in 1995. In the system, the carbon tank electromagnetic valve controls gas in the carbon tank to enter the air inlet manifold to enter the engine to participate in combustion, so that the effects of energy conservation and emission reduction are achieved. The change of the national six is that the capacity of the carbon tank is increased, the inner diameter of a desorption pipeline is increased, the electromagnetic valve of the carbon tank generates larger pressure pulsation when the accelerator is opened, and the problem of unobvious noise is highlighted.

How to reduce low-frequency noise in a fuel oil evaporative emission system and how to realize the miniaturization of a silencer is a problem to be solved by a fuel oil evaporative emission control system.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is to provide a muffler for car fuel evaporation pipe in order to overcome the obvious defect of noise among the prior art fuel evaporation emission control system.

The utility model discloses an above-mentioned technical problem is solved through following technical scheme:

a silencer for an automobile fuel evaporation pipe is characterized by comprising:

the device comprises an upper shell, a first connecting module and a second connecting module, wherein the first connecting module is connected with the outer part of the upper shell, the two ends of the first connecting module are communicated with each other;

the lower shell is externally connected with a second connecting module with two through ends, a second inner tube with two through ends is connected into the lower shell, one end of the second inner tube is communicated with one end of the second connecting module, and the upper shell and the lower shell are connected with each other and form an expansion cavity.

Preferably, the length of the first inner tube is equal to one-half of the length of the expansion cavity.

Preferably, the length of the second inner tube is equal to one quarter of the length of the expansion cavity.

Preferably, sound-absorbing sponges are arranged on the inner walls of the upper shell and the lower shell.

Preferably, the inner wall of the upper shell is provided with an inner step, the outer wall of the lower shell is provided with an outer step, and the outer step is matched with the inner step.

Preferably, the upper housing is made of opaque material, and the lower housing is made of transparent material.

Preferably, the first connection module is a quick adapter.

Preferably, the second connecting module is a cold insertion tube with a laminated pagoda-shaped outer peripheral surface.

Preferably, the outer circumferential surface of the second connection module is sleeved with a sealing ring.

On the basis of the common knowledge in the field, the above preferred conditions can be combined at will to obtain the preferred embodiments of the present invention.

The utility model discloses an actively advance the effect and lie in: the problem that the sound silencing effect of the silencer on certain frequencies is zero can be solved by arranging the first inner pipe and the second inner pipe in the expansion cavity of the silencer.

Drawings

Fig. 1 is a graph showing the transmission loss curve of the middle expansion chamber type muffler of the present invention, wherein the expansion ratio is different in each sample.

Fig. 2 is a graph showing the transmission loss curve of the middle expansion chamber type muffler of the present invention, wherein the length of the expansion chamber is different in each sample.

Fig. 3 is a graph comparing the transmission loss curves of the medium-expansion chamber of the present invention with and without the cannula.

Fig. 4 is a schematic perspective view of a muffler for an automobile fuel evaporation pipe according to a preferred embodiment of the present invention.

Fig. 5 is a schematic view showing the internal cross-sectional structure of a muffler for an automobile fuel evaporator according to a preferred embodiment of the present invention.

Description of reference numerals:

upper case 100

First connection module 110

First inner tube 120

Inner step 130

Lower case 200

Second connection module 210

Second inner tube 220

Outer step 230

Expansion chamber 300

Sound-absorbing sponge 400

Seal ring 500

Detailed Description

The present invention will be more clearly and completely described below with reference to the accompanying drawings.

The pipe section with the suddenly changed cross section or the resonant cavity is connected to the pipeline, and the sound waves with certain frequencies are reflected and interfered on the interface with the suddenly changed acoustic impedance by changing the acoustic impedance, so that the aim of silencing the sound at the outer side of the silencer is fulfilled. The formula for calculating the sound attenuation of the expansion cavity type is as follows:

m-muffler expansion ratio; l-expansion lumen length, m; k-conversion coefficient.

The influence factors of the noise elimination effect of the expansion cavity type muffler can be known by the formula: the expansion ratio m; the length of the dilatation lumen l. The transmission loss curve of the expansion cavity type silencer is a circulation curve, m influences the wave crest of the curve, and l influences the circulation period of the curve. The simulation analysis is carried out on the silencers with different expansion ratios and different expansion cavity lengths based on COMSOL software, and a conclusion is drawn based on the analysis result.

The length l of the expansion cavities of the samples 1, 2 and 3 is 60mm, and the expansion ratios m are 4, 9 and 16 respectively;

the expansion ratios m of the samples 4, 5 and 6 are the same as 9, and the lengths l of the expansion cavities are 40mm, 60mm and 80mm respectively;

as can be seen from fig. 1, when the length of the expansion chamber is kept constant, the expansion ratio m increases, and the transmission loss TL increases. The shapes of the three curves are similar, and the passing frequency and the peak frequency are the same, so that the trend that the change of the expansion ratio m does not affect the curves is shown, and only the amplitude change corresponding to each frequency is affected.

As can be seen from fig. 2, when the expansion ratio m is kept constant, the expansion chamber length l increases, the shape of the transmission loss curve is almost unchanged, and the amount of noise cancellation at the peak frequency is uniform, but the noise cancellation period varies. When the length l is increased, the whole curve moves towards the low-frequency direction; when the length l is reduced, the entire curve moves in the high-frequency direction.

It follows that increasing the expansion ratio m of the expansion chamber increases the peak value of the transmission loss curve, and increasing the length l of the expansion chamber may shift the transmission loss curve as a whole in the low frequency direction. Increasing m and l is beneficial to improving the silencing effect of the silencer at a low frequency section, and the requirement of vehicle installation space is considered.

The diverging chamber 300 muffler presents a pass frequency,

namely when

When the passing frequency is

Where λ is the acoustic wavelength and c is the speed of sound.

To eliminate the pass frequency, there are two methods: firstly, silencers with different specifications are connected in series; secondly, inserting inner tubes into two ends of the expansion cavity respectively to eliminate the passing frequencies with n being odd number and even number respectively.

Fig. 4 and 5 show a silencer for a fuel evaporator pipe of a motor vehicle, comprising: an upper case 100 and a lower case 200. The first connection module 110 with two through ends is connected to the outside of the upper casing 100, the first inner tube 120 with two through ends is connected to the inside of the upper casing 100, and one end of the first inner tube 120 is connected to one end of the first connection module 110. The second connection module 210 having two through ends is connected to the outside of the lower case 200, the second inner tube 220 having two through ends is connected to the inside of the lower case 200, one end of the second inner tube 220 is connected to one end of the second connection module 210, and the upper case 100 and the lower case 200 are connected to each other to form the expansion chamber 300. The problem of the muffler having zero sound-deadening effect for certain frequencies can be solved by providing the first inner pipe 120 and the second inner pipe 220 in the expansion chamber 300 of the muffler.

In this embodiment, the length of the first inner tube 120 is equal to one-half of the length of the expansion chamber 300, and the length of the second inner tube 220 is equal to one-quarter of the length of the expansion chamber 300.

The insertion of the first inner tube 120 having the length 1/2 of the expansion chamber 300 and the second inner tube 220 having the length 1/4 of the expansion chamber 300 at both ends of the expansion chamber 300 can eliminate the passing frequencies where n is odd and even, respectively.

Sample 5: the expansion ratio is 9, the length of the expansion cavity 300 is 60mm, and no inner intubation is arranged;

sample 7: the expansion ratio is 9, the length of the expansion cavity 300 is 60mm, and the inner cannula is not 30mm or 15 mm.

The results of the simulation analysis are shown in FIG. 3. As can be seen from fig. 3, when the expansion chamber 300 is inserted into the inner joint, not only the passing frequency is eliminated, but also the noise reduction effect of the muffler is enhanced in the frequency region after the 400Hz frequency. And the scheme II increases the noise elimination effect of the product under the condition of not changing the appearance of the product.

In this embodiment, the sound-absorbing sponge 400 is disposed on the inner walls of the upper casing 100 and the lower casing 200. The noise in the muffler can be effectively reduced by using the sound-absorbing sponge 400.

The inner wall of the upper casing 100 is provided with an inner step 130, the outer wall of the lower casing 200 is provided with an outer step 230, and the outer step 230 is matched with the inner step 130. The outer step 230 and the inner step 130 are matched to facilitate the accurate connection of the upper case 100 and the lower case 200.

The upper housing 100 is made of opaque material, and the lower housing 200 is made of transparent material. The light-transmitting material and the light-tight material are combined to facilitate laser welding, so that the upper shell 100 and the lower shell 200 are welded reliably and have good sealing performance. The upper case 100 may be made of light-proof Polyamide (PA), Polyoxymethylene (POM), polyphenylene sulfide (PPS), Polyethylene (PE), or the like. The material of the lower case 200 may be light-transmitting Polyamide (PA), Polyoxymethylene (POM), polyphenylene sulfide (PPS), Polyethylene (PE), or the like.

The first connection module 110 is a fast adapter. The second connection module 210 is a cold insertion tube having a stacked pagoda-shaped outer peripheral surface. Utilize quick adapter and cold intubate can be convenient for the muffler and be connected with car fuel evaporating pipe.

The outer circumferential surface of the second connection block 210 is fitted with a packing 500. The sealing ring 500 is used to further improve the sealing between the cold insertion tube and the fuel evaporation tube of the automobile.

Although specific embodiments of the present invention have been described above, it will be understood by those skilled in the art that this is by way of example only and that the scope of the invention is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the spirit and the principles of the present invention, and these changes and modifications are all within the scope of the present invention.

Claims (9)

1. A silencer for an automobile fuel evaporation pipe is characterized by comprising:

the device comprises an upper shell, a first connecting module and a second connecting module, wherein the first connecting module is connected with the outer part of the upper shell, the two ends of the first connecting module are communicated with each other;

the lower shell is externally connected with a second connecting module with two through ends, a second inner tube with two through ends is connected into the lower shell, one end of the second inner tube is communicated with one end of the second connecting module, and the upper shell and the lower shell are connected with each other and form an expansion cavity.

2. The muffler for an automotive fuel evaporator tube of claim 1, wherein the length of the first inner tube is equal to one-half of the length of the expansion chamber.

3. The muffler for an automotive fuel evaporator tube of claim 2, wherein the length of the second inner tube is equal to one-quarter of the length of the expansion chamber.

4. The muffler for a fuel evaporator tube of an automobile as set forth in claim 1, wherein sound-absorbing sponges are provided on inner walls of the upper case and the lower case.

5. The muffler for a fuel evaporation pipe of an automobile as claimed in claim 1, wherein an inner step is formed on an inner wall of the upper casing, and an outer step is formed on an outer wall of the lower casing, the outer step being matched with the inner step.

6. The muffler for an automotive fuel evaporator as set forth in claim 5, wherein said upper casing is made of a light-impermeable material and said lower casing is made of a light-permeable material.

7. The muffler for a vehicle fuel evaporator pipe of claim 1, wherein the first connection module is a quick-change adapter.

8. The muffler for an automobile fuel evaporator according to claim 1, wherein the second connection module is a cold insertion pipe having a laminated pagoda-shaped outer circumferential surface.

9. The muffler for a fuel evaporator of an automobile as set forth in claim 8, wherein a packing is fitted over an outer circumferential surface of the second connection block.

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