CN211819570U

CN211819570U - Composite muffler with adjustable expansion ratio

Info

Publication number: CN211819570U
Application number: CN202020528973.3U
Authority: CN
Inventors: 李想; 张袁元; 李昕鸣; 单榴; 吉睦程
Original assignee: Nanjing Institute of Technology
Current assignee: Nanjing Institute of Technology
Priority date: 2020-04-13
Filing date: 2020-04-13
Publication date: 2020-10-30
Anticipated expiration: 2030-04-13

Abstract

The utility model relates to a composite muffler with adjustable expansion ratio, which has the characteristics of small size and simple structure, and concretely comprises a shell, a tail gas inlet pipe, a tail pipe, a clapboard and a perforated pipe, wherein the clapboard is arranged in the shell of the muffler in parallel, the clapboard divides the interior of the shell of the muffler into a first chamber, a second chamber, a third chamber, a fourth chamber and a fifth chamber along the direction from the tail gas inlet pipe to the tail pipe, the perforated pipe is divided into a first perforated pipe, a second perforated pipe and a third perforated pipe, the first perforated pipe extends from the first chamber to the third chamber, the second perforated pipe and the third perforated pipe are symmetrically distributed along the axial direction and extend from the third chamber to the fifth chamber, a butterfly valve capable of controlling the exhaust flow is arranged at the outlet end of the tail gas inlet pipe, the utility model adopts an impedance composite muffling structure, the performance of the muffler is further improved by controlling the rotation angle of the butterfly valve, and optimizing the NVH performance of the automobile.

Description

Composite muffler with adjustable expansion ratio

Technical Field

The utility model relates to the technical field of auto-parts, concretely relates to combined type silencer of adjustable expansion ratio.

Background

In recent years, with the improvement of living standard of people, the requirement on the comfort of cars is higher and higher, the NVH performance of automobiles is more and more important, and the automobile silencer gradually becomes a research hotspot. At present, the widely used mufflers are mainly resistive or reactive mufflers with simple structures, and the air flow flows through the resistive cavity and the reactive cavity of the muffler, contacts with the resistive material and passes through the resonance muffling effect of air so as to achieve the purpose of muffling. However, nowadays, with the increasingly complex road conditions, the traditional muffler with a single structure is difficult to meet the muffling requirements under different working conditions, and the muffling amount of different frequency bands is greatly different, so that the muffling effect under different working conditions is not ideal, and the driving feeling of people is affected.

The exhaust muffler has the function of reducing exhaust noise by gradually reducing exhaust pressure and exhaust pulsation, so that noise pollution to the environment is reduced. For passenger cars, a good muffler should not only have good acoustic and aerodynamic properties (i.e., large amount of sound damping, low back pressure of exhaust), but also be small, lightweight, simple in construction, robust, and the like.

Transmission loss is one of important evaluation indexes of the silencer, and m = D ^2 ⁄ D ^2 for a round pipeline, and D and D are the diameter of the expansion cavity and the diameter of the exhaust pipe respectively. For an irregular exhaust runner, m = S2 ⁄ S1, the transmission loss depends on the ratio of the cross-sectional areas. The transmission loss of the silencer is not only the loss of sound energy, but also the loss of pressure, the transmission loss is related to the size of the silencing quantity, most silencers achieve the silencing purpose through the arrangement of the ratio of the cross sections, however, the design only can be used for silencing treatment when the tail gas flow is large under medium and high load conditions, and low-frequency noise generated during exhaust cannot be effectively reduced when the tail gas flow of an engine is small under low speed or idling conditions. Therefore, the development of the muffler capable of adapting to different working conditions of the engine and adjusting the expansion ratio has great significance for the NVH performance of the automobile.

SUMMERY OF THE UTILITY MODEL

Technical problem to be solved

The utility model aims at providing a be applicable to the silencer of small-size adjustable expansion ratio who takes advantage of car to the not enough of current silencer existence, adopt to install in the butterfly valve adjustment mechanism of tail gas intake pipe exit end, the inside impedance combined type noise elimination unit of casing, expand two kinds of noise elimination methods of noise elimination and resonance noise elimination, further promote the noise elimination performance and the aerodynamic performance of silencer.

(II) technical scheme

In order to achieve the above object, the utility model provides a following technical scheme: the utility model provides an adjustable expansion ratio's combined type silencer, includes silencer casing, tail gas intake pipe, tail pipe, baffle, perforated pipe and butterfly valve, the tail gas intake pipe with the tail pipe is installed in the both ends of silencer casing along the silencer axial, the butterfly valve install in tail gas intake pipe exit end, the butterfly valve passes through the valve plate and fixes, the valve plate set up in silencer casing intake end lateral wall is fixed and respectively with tail gas intake pipe and adjustment mechanism are connected.

The partition plates comprise a first partition plate, a second partition plate, a third partition plate and a fourth partition plate, and are arranged in the silencer shell in parallel, the partition plates divide the interior of the silencer shell into five chambers, and the chambers are respectively a first chamber, a second chamber, a third chamber, a fourth chamber and a fifth chamber along the direction from the tail gas inlet pipe to the tail pipe;

the perforated pipes comprise a first perforated pipe, a second perforated pipe and a third perforated pipe, the first perforated pipe is axially arranged at the centers of the first partition plate and the second partition plate, two ends of the first perforated pipe are respectively positioned in the first cavity and the third cavity, the second perforated pipe and the third perforated pipe penetrate through the third partition plate in the axial direction and are symmetrically distributed with the fourth partition plate, and two ends of the second perforated pipe and the third perforated pipe are respectively positioned in the third cavity and the fifth cavity;

further, adjustment mechanism comprises butterfly valve disk seat, control module and adjustment handle, butterfly valve disk seat lower extreme and tail gas intake pipe welded connection, adjustment handle with the butterfly valve disk seat is connected, control module with the butterfly valve disk seat is connected.

Preferably, the section diameter of the tail gas inlet pipe is 1.3-1.5 times the length of the section diameter of the first perforated pipe.

Preferably, a baffle is vertically arranged in the center of the inner wall of the first perforated pipe, the baffle is connected with the inner wall of the first perforated pipe in a welding manner, perforations are uniformly arranged on the pipe wall of the first perforated pipe in the second chamber, the baffle divides a perforated area in the second chamber into two parts, the diameter of a through hole in the second chamber is 3-5mm, the perforation rate is 10% -15%, the through hole can play a role in resonance noise elimination and expansion noise elimination, the expansion ratio can be continuously changed in the first chamber and the second chamber by changing the diameter and the perforation rate within a given range, exhaust noise is effectively reduced, the propagation speed of sound waves is increased when the temperature is increased, the frequency of the sound waves is increased when the wavelength is constant, so that the transmission loss of the cross-flow perforated pipe moves to high frequency, and sound absorbing materials are attached to the inner wall sides of the first chamber and the second chamber, can play better noise cancelling effect to the gas that flows, the gas that is located second chamber perforated pipe has the part to be blockked by the baffle and pass the through-hole again for gas is inside and outside mutual reflection, interference in the perforated pipe, further improves noise cancelling effect.

Preferably, the second perforated pipe and the third perforated pipe are provided with perforated areas, the pipe walls of the second perforated pipe and the third perforated pipe in the fourth chamber are provided with perforations, and the perforation rate is less than 5%.

Preferably, the second perforated tube and the third perforated tube are both single-sided perforated, the second perforated tube is perforated only in the upper half and the third perforated tube is perforated only in the lower half.

Preferably, the first perforated tube is between 1/4-1/3 of the first chamber's axial length and the first perforated tube is between 1/5-1/4 of the third chamber's axial length.

Preferably, the second perforated tube and the third perforated tube are arranged along the axis in a parallel and symmetrical manner, wherein the length of the third chamber is 1/6-1/5 of the length of the third chamber, and the length of the fifth chamber is 1/10-1/8 of the axial length of the fifth chamber.

Preferably, the second perforated tube and the third perforated tube are of the same diameter and length, and the second perforated tube and the third perforated tube are of smaller diameter than the first perforated tube.

(III) compared with the prior art, has the following beneficial effects

Compared with the prior art, the utility model relates to a combined type silencer of adjustable expansion ratio, through installing butterfly valve adjustment mechanism at tail gas intake pipe end, through the angle of control butterfly valve rotation, can reach the purpose of adjusting the exhaust flow area and then changing the expansion ratio, and then can satisfy the adjustment of expansion ratio under the different speeds of a motor vehicle; when the vehicle is at low speed or idling, the butterfly valve is adjusted to reduce the flow area of the exhaust and air inlet end, the expansion ratio is enlarged to increase the acoustic transmission loss, and the noise elimination capability of the silencer on low frequency is improved; under the working conditions of medium and high speed, the exhaust volume is large, the speed is high, so that large friction noise can be caused, the design that the diameter of the tail gas inlet pipe is 1.3-1.5 times that of the first perforated pipe can adapt to the exhaust flow at each rotating speed to the maximum extent, the flow area of the exhaust inlet end is increased by adjusting the butterfly valve, the exhaust noise is reduced, and the exhaust pressure is reduced; in addition, through the impedance combined type noise elimination unit of multicavity room, combine the structural arrangement of unilateral perforated pipe, when guaranteeing the good noise elimination performance of silencer itself, its aerodynamic performance has also obtained the promotion, and the structure is simple relatively, small for this silencer has fine practicality.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is an axial sectional view of the present invention.

Fig. 2 is a schematic diagram of the internal structure of the present invention.

Fig. 3 is a three-dimensional schematic diagram of the appearance of the present invention.

In the drawings, the components represented by the respective reference numerals are listed below:

the silencer comprises a silencer shell 1, a tail gas inlet pipe 2, a tail gas pipe 3, a partition plate 4, a first partition plate 4-1, a second partition plate 4-2, a third partition plate 4-3, a fourth partition plate 4-4, a first perforated pipe 5, a second perforated pipe 6-1, a third perforated pipe 6-2, a butterfly valve 7, a baffle plate 8, a valve plate 9, an adjusting mechanism 10, a butterfly valve seat 10-1, a control module 10-2 and an adjusting handle 10-3.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

As shown in fig. 1, a composite muffler with adjustable expansion ratio comprises a muffler shell 1, a tail gas inlet pipe 2, a tail pipe 3, a partition plate 4, a perforated pipe and a butterfly valve 7, wherein the tail gas inlet pipe 2 and the tail pipe 3 are axially mounted at two ends of the muffler shell 1, the butterfly valve 7 is mounted at an outlet end of the tail gas inlet pipe 2, the butterfly valve 7 is fixed through a valve plate 9, and the valve plate 9 is fixed on the side wall of the inlet end of the muffler shell 1 and is respectively connected with the tail gas inlet pipe 2 and an adjusting mechanism 10.

The partition plates 4 comprise a first partition plate 4-1, a second partition plate 4-2, a third partition plate 4-3 and a fourth partition plate 4-4 which are arranged in the silencer shell 1 in parallel, the partition plates 4 divide the interior of the silencer shell 1 into five chambers, and the chambers are respectively a first chamber, a second chamber, a third chamber, a fourth chamber and a fifth chamber along the direction from the tail gas inlet pipe 2 to the tail gas exhaust pipe 3; the first chamber plays a role in expansion, and the first chamber and the butterfly valve adjusting mechanism 10 can effectively control the flow area of the exhaust airflow, change the expansion ratio and play a role in buffering high-speed airflow.

The perforated pipes comprise a first perforated pipe 5, a second perforated pipe 6-1 and a third perforated pipe 6-2, the first perforated pipe 5 is axially arranged at the centers of a first partition plate 4-1 and a second partition plate 4-2, two ends of the first perforated pipe 5 are respectively positioned in a first cavity and a third cavity, the second perforated pipe 6-1 and the third perforated pipe 6-2 axially penetrate through the third partition plate 4-3 and are symmetrically distributed with a fourth partition plate 4-4, and two ends of the second perforated pipe and the third perforated pipe are respectively positioned in the third cavity and a fifth cavity; the adjusting mechanism 10 is composed of a butterfly valve seat 10-1, a control module 10-2 and an adjusting handle 10-3, the lower end of the butterfly valve seat 10-1 is connected with a tail gas inlet pipe 2 in a welding mode, the adjusting handle 10-3 is connected with the butterfly valve seat 10-1, and the control module 10-2 is connected with the butterfly valve seat 10-1. The exhaust airflow flows in from the exhaust gas inlet pipe 2, expands in the first chamber after passing through the butterfly valve adjusting mechanism 10, the sound absorption material filled in the inner wall of the first chamber absorbs high-frequency noise to a certain degree, then the airflow flows in the first perforated pipe 5, the partition plate 4 is designed to ensure that high-speed airflow flows out in a divergent manner from the perforated area and flows into the perforated area on the other side and then enters the third chamber for catalytic reaction, the catalyzed exhaust gas passes through the second perforated pipe 6-1 and the third perforated pipe 6-2, the single-side perforated structure of the second perforated pipe 6-1 and the third perforated pipe 6-2 and the inner wall of the shell respectively form two Helmholtz resonant cavities, the noise in a specific frequency range is further weakened, finally the exhaust gas is contracted through the fifth chamber and then is discharged from the exhaust tail pipe 3, and the impedance composite structure of the multi-chamber can reduce most of sound energy, meanwhile, the straight-through structure and the single-side perforated structure obviously improve the aerodynamic performance of the silencer.

An adjusting mechanism 10 of a butterfly valve 7 is arranged at the outlet end of a tail gas inlet pipe 2, the front and the back are respectively connected with the tail gas inlet pipe 2 and a silencer shell 1, a valve plate 9 is arranged on the outer wall of the outlet end of the tail gas inlet pipe 2 and is connected by screws and bolts to play a role in fixing, the stability of the butterfly valve 7 during working is improved, a butterfly valve seat 10-1 is connected with the valve plate 9 and is fixed close to the side wall of the air inlet end of the shell to reduce air flow fluctuation and vibration noise caused by engine working, an adjusting handle 10-3 is connected with the butterfly valve seat 10-1 and controls the rotation angle of the butterfly valve 7 through an adjusting valve shaft, wherein a control module 10-2 is a butterfly valve controller, the capacity of the butterfly valve 7 for adjusting the exhaust through-flow area can be fully exerted by the design that the diameter of the tail gas inlet pipe 2, the exhaust flow is not large, the flow area of the air inlet end can be reduced by adjusting the butterfly valve 7, so that a larger expansion ratio is obtained, the acoustic transmission loss is increased, and the noise elimination effect of the silencer on low-frequency noise is improved; when the vehicle is at medium and high speed, the exhaust flow is large and the speed is high, at the moment, the butterfly valve 7 is adjusted to increase the exhaust flow area, exhaust noise is reduced, exhaust back pressure is reduced, the muffler can obtain the best balance between the noise elimination performance and the aerodynamic performance by adjusting the butterfly valve 7, and the comfort and the dynamic performance of the vehicle are improved in a larger engine rotating speed range.

The first perforated pipe 5 is arranged between 1/4-1/3 of the first chamber in length, 1/5-1/4 of the third chamber in length, the baffle 8 is arranged in the center of the inner wall of the first perforated pipe, the baffle 8 is connected with the inner wall of the first perforated pipe 5 in a welding mode, the first perforated pipe 5 is provided with a perforated area, the perforated area is located in the second chamber, the diameter of each through hole is 3-5mm, and the perforation rate is 10% -15%, so that the resonance silencing effect and the expansion silencing effect can be achieved. The expansion ratio can be continuously changed in the first cavity and the second cavity by changing the diameter of the through hole and the size of the perforation rate within a given range, the range of the noise elimination frequency is enlarged, the inner walls of the first cavity and the second cavity are filled with noise elimination materials, the middle and high frequency noise can be effectively eliminated, the partition plate 4 can enable airflow to flow out from the through hole in a divergent shape, part of the air is blocked by the partition plate 4 and then passes through the through hole again, the air is reflected and interfered inside and outside the perforated pipe, the noise elimination effect is further improved, then the airflow flows into the third cavity from the other side through the through hole and passes through the catalytic carrier, residual harmful nitrogen oxides in tail gas react with the catalytic carrier and are reduced into harmless gas, and the purified gas enters the second perforated pipe 6-1 and the third perforated pipe 6-2 through shunting.

The length of the second perforated pipe 6-1 and the third perforated pipe 6-2 in the third chamber is 1/6-1/5 of the length of the third chamber, the length of the fifth chamber is 1/10-1/8 of the length of the fifth chamber, the second perforated pipe 6-1 and the third perforated pipe 6-2 adopt a single-side perforated structure, the fourth chamber is divided into two independent Helmholtz resonance chambers, the influence of a complex flow field caused by flowing and sweeping is reduced, meanwhile, the pressure loss caused by the close distance of perforated areas of the perforated pipes is reduced, the aerodynamic performance of the silencer is improved, the perforated areas are located in the fourth chamber, the diameter of a through hole is preferably 1-2mm, the perforation rate is less than 5%, and finally, after the air flows through the fifth chamber shrink and the flow rate is reduced, the air is discharged from an exhaust tail pipe.

The installation positions of the second perforated pipe 6-1 and the third perforated pipe 6-2 can be arranged according to the specific requirements on the performance of the silencer, and the positions can be adjusted to change the volumes of two independent Helmholtz resonant cavities, so that the silencing peak value moves to the specified frequency, and the silencing efficiency of the silencer is improved.

In the description herein, references to the description of "one embodiment," "an example," "a specific example," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. The preferred embodiments are not exhaustive and do not limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best understand the invention for and utilize the invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. The utility model provides an adjustable expansion ratio's combined type silencer which characterized in that: the silencer comprises a silencer shell (1), a tail gas inlet pipe (2), a tail pipe (3), a partition plate (4), a perforated pipe and a butterfly valve (7), wherein the tail gas inlet pipe (2) and the tail pipe (3) are axially mounted at two ends of the silencer shell (1) along a silencer, the butterfly valve (7) is mounted at the outlet end of the tail gas inlet pipe (2), the butterfly valve (7) is fixed through a valve plate (9), and the valve plate (9) is arranged on the side wall of the inlet end of the silencer shell (1) and is fixed with the tail gas inlet pipe (2) and an adjusting mechanism (10) respectively; the partition plates (4) comprise a first partition plate (4-1), a second partition plate (4-2), a third partition plate (4-3) and a fourth partition plate (4-4) which are arranged in parallel inside the silencer shell (1), the partition plates (4) divide the inside of the silencer shell (1) into five chambers, and the chambers are respectively a first chamber, a second chamber, a third chamber, a fourth chamber and a fifth chamber along the direction from the tail gas inlet pipe (2) to the tail pipe (3);

the perforated pipe comprises a first perforated pipe (5), a second perforated pipe (6-1) and a third perforated pipe (6-2), wherein the first perforated pipe (5) is axially arranged at the center of the first partition plate (4-1) and the second partition plate (4-2), two ends of the first perforated pipe (5) are respectively arranged in the first cavity and the third cavity, the second perforated pipe (6-1) and the third perforated pipe (6-2) axially penetrate through the third partition plate (4-3) and the fourth partition plate (4-4) and are symmetrically distributed, and two ends of the second perforated pipe and the third perforated pipe are respectively arranged in the third cavity and the fifth cavity.

2. The compound muffler with adjustable expansion ratio of claim 1, wherein: the adjusting mechanism (10) is composed of a butterfly valve seat (10-1), a control module (10-2) and an adjusting handle (10-3), the lower end of the butterfly valve seat (10-1) is connected with a tail gas inlet pipe (2) in a welding mode, the adjusting handle (10-3) is connected with the butterfly valve seat (10-1), and the control module (10-2) is connected with the butterfly valve seat (10-1).

3. The compound muffler with adjustable expansion ratio of claim 1, wherein: the section diameter of the tail gas inlet pipe (2) is 1.3-1.5 times the length of the section diameter of the first perforated pipe (5).

4. The compound muffler with adjustable expansion ratio of claim 1, wherein: the inner wall center of the first perforated pipe (5) is vertically provided with a baffle (8), the baffle (8) is connected with the inner wall of the first perforated pipe (5) in a welding manner, perforations are uniformly arranged on the pipe wall of the first perforated pipe (5) in the second chamber, and the perforation rate is 10% -15%.

5. The compound muffler with adjustable expansion ratio of claim 1, wherein: the second perforated pipe (6-1) and the third perforated pipe (6-2) are provided with perforated areas, the pipe walls of the second perforated pipe (6-1) and the third perforated pipe (6-2) in the fourth chamber are provided with perforations, and the perforation rate is less than 5%.

6. The compound muffler with adjustable expansion ratio of claim 5, wherein: the second perforated tube (6-1) and the third perforated tube (6-2) are both single-sided perforated, the second perforated tube (6-1) is perforated only in the upper half, and the third perforated tube (6-2) is perforated only in the lower half.

7. The compound muffler with adjustable expansion ratio of claim 3, wherein: the first perforated tube (5) is between 1/4-1/3 of the first chamber's axial length and the first perforated tube (5) is between 1/5-1/4 of the third chamber's axial length.

8. The compound muffler with adjustable expansion ratio of claim 4, wherein: the second perforated pipe (6-1) and the third perforated pipe (6-2) are distributed along the axis in a parallel and symmetrical mode, wherein the length of the third chamber is 1/6-1/5 of the length of the third chamber, and the length of the fifth chamber is 1/10-1/8 of the axial length of the fifth chamber.

9. The compound muffler with adjustable expansion ratio of claim 4, wherein: the second perforated tube (6-1) and the third perforated tube (6-2) have the same diameter and length, and the second perforated tube (6-1) and the third perforated tube (6-2) have a smaller diameter than the first perforated tube (5).