JP2001090523A - Muffler for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a muffler for a vehicle capable of attaining a noise eliminating effect for an exhaust noise ranging over a wide frequency domain while reducing cost. SOLUTION: This muffler has a characteristic feature that a metal carrier 31 having a large number of exhaust passages and a large number of small bores communicated to the passages is attached in an exhaust flow passage of a vehicular exhaust system. In the muffler, the metal carrier 31 is constituted by layering thin corrugated plates having a large number of small bores and thin plane plates having a large number of small bores overlappedly and alternately to be wound multi-layeredly, or alternatively, the metal carrier 31 is constituted by winding the thin corrugated plate having the large number of small bores to be multi-layered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a muffler mounted on a vehicle exhaust system.

[0002]

2. Description of the Related Art In order to reduce exhaust noise during vehicle running,
2. Description of the Related Art Conventionally, a muffler is mounted on a vehicle exhaust system, and exhaust noise is silenced by an expansion damping action in an expansion chamber of the muffler and a resonance damping action in a resonance chamber. However, since the conventional muffler has a small rectifying effect of exhaust pulsation, it has a small effect of reducing radiation noise and airflow noise.
As disclosed in JP-A-53710, a sound absorbing chamber filled with glass wool in a cylindrical body is mounted in a muffler, and exhaust noise of high-frequency components is silenced in the sound absorbing chamber. By reducing the noise and increasing the capacity of the resonator, the exhaust noise of low and medium frequency components was reduced.

[0003]

However, in the above-mentioned sound absorbing chamber, glass wool is scattered due to pulsation of exhaust gas from the engine and thermal deterioration of the glass wool, causing secondary pollution or deteriorating the noise reduction performance. The fear was pointed out. Further, it has been pointed out that mounting the sound absorbing chamber as described above or increasing the muffler rigidity increases the cost, and further, increasing the capacity of the resonator increases the size of the entire muffler.

[0004] The present invention has been devised in view of the above circumstances, and has as its object to provide a noise reduction device for a vehicle which can reduce noise and achieve an exhaust noise reduction effect over a wide frequency range while reducing costs. I do.

[0005]

According to a first aspect of the present invention, there is provided a vehicle muffler including a plurality of exhaust gas passages and a plurality of small holes connected to the exhaust gas passages in a vehicle exhaust system. Characterized in that a metal carrier having:

The invention according to claim 2 is based on claim 1
In the vehicle noise reduction device described above, the metal carrier is formed by alternately stacking a thin corrugated sheet having a large number of small holes and a thin flat plate having a large number of small holes, and winding these in multiple layers. According to a third aspect of the present invention, in the vehicle silencer according to the first aspect, the metal carrier is formed by winding a thin corrugated sheet having a large number of small holes in multiple layers. .

According to a fourth aspect of the present invention, in the muffler for a vehicle according to any one of the first to third aspects, the metal carrier is a muffler pipe of a muffler mounted on a vehicle exhaust system. The invention according to claim 5 is characterized in that the metal carrier is provided in the vehicle exhaust system in the vehicle silencer according to any one of claims 1 to 3. It is mounted in the front tube.

(Action) According to the silencer according to each claim, a sound wave is transmitted to a large number of exhaust gas passages through a large number of small holes of the metal carrier, and the sound wave oscillating at that time and the thin shape of the metal carrier. Due to friction with a corrugated sheet, a thin flat plate, or the like, or friction with the wall surface of a small hole that passes through, sound wave energy of a high-frequency component is converted into heat energy, thereby achieving noise reduction.

Further, when the exhaust pulsation generated from the engine passes through the metal carrier, the pressure level of the exhaust pulsation is reduced by the rectifying action of the metal carrier, so that the radiation noise from the vehicle exhaust system is suppressed. In the present specification, the thin flat plate includes a thin plate having a waveform sufficiently smaller than that of the thin corrugated plate.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a vehicle silencer according to a first embodiment of claims 1, 2 and 4,
In the drawing, reference numeral 1 denotes a main muffler attached to a vehicle exhaust system.
The interior of the cylindrical shell 7 closed by the above is partitioned by two baffle plates 9 and 11, and three silences of the first chamber 13, the second chamber 15 and the third chamber 17 are arranged from the end plate 3 side on the exhaust gas upstream side. A chamber is defined.

An inlet pipe 19 is inserted into the end plate 3 so as to penetrate the baffle plate 9, and the insertion side end (extended portion) 19 a of the end pipe 3 is in the second chamber 15.
It is open to. Further, an outlet pipe 21 is inserted into the downstream end plate 5 through the baffle plates 9 and 11, and the outlet pipe 21 is
Has an insertion-side end (flow contracting portion) 21 a opened in the first chamber 13, and a plurality of small holes 23 formed in the peripheral wall located in the second chamber 15.

Further, a resonator pipe 25 for communicating the second chamber 15 and the third chamber 17 is inserted into the baffle plate 11 coaxially with the inlet pipe 19, and the first chamber 13 is connected to the baffle plate 9. One communication pipe 27 that connects the first chamber 13 and the second chamber 15 is inserted, and the first chamber 13 and the second chamber 15 function as an expansion chamber by such a configuration, and the third chamber 17 resonates. It functions as a room.

The silencer 29 according to the present embodiment
Is characterized in that a metal carrier 31 having a large number of exhaust gas passages and a large number of small holes connected thereto is mounted in the insertion side end 21a of the outlet pipe 21. FIG.
As shown in FIG. 4 to FIG.
3 and a thin flat plate 39 having a large number of small holes 37 are alternately stacked and formed into a thick cylindrical shape by winding these in multiple layers. And the thin flat plate 39 function as an exhaust gas passage, and a large number of small holes 33, 3 are provided between the cells 41.
7 are connected to each other.

The thin corrugated plate 35 and the thin flat plate 39
Is SUS304, SUS410, or SUS430
Using a stainless steel foil, the thickness of which is several tens of micrometers,
Although the diameters of the small holes 33 and 37 are set in the range of φ0.5 to φ6, the small holes 33 and 37 depend on which of the low and medium frequency component exhaust noise and the high frequency component exhaust noise is preferentially silenced. The pitches and diameters of the small holes 33 and 37 are preferably small in order to reduce the high frequency component exhaust noise, and the small holes 33 and 37 are mainly used for the rectification of exhaust pulsation.
The larger the diameter of 37 is, the better.

Since the present embodiment is configured as described above, the exhaust noise introduced into the main muffler 1 through the inlet pipe 19 is reduced to the first chamber 1 which functions as an expansion chamber.
3, the sound is attenuated by the extended damping action in the second chamber 15 and the resonance damping action in the third chamber 19 functioning as the resonance chamber, and the thin-walled wave is formed through the many small holes 33, 37 of the metal carrier 31. The sound wave is propagated to a number of cells (exhaust gas passages) 41 between the plate 35 and the thin plate 39, and the sound wave oscillated at that time is caused by friction between the thin corrugated plate 35 and the thin plate 39, or the small wave passing therethrough. Due to friction with the wall surfaces of the holes 33 and 37, sound wave energy of a high-frequency component is converted into heat energy, thereby achieving noise reduction.

As described above, it is said that the smaller the diameter and pitch of the small holes 33 and 37, the better the noise reduction performance of high frequency components. Further, when the exhaust pulsation generated from the engine passes through the metal carrier 31, the metal carrier 31 functions as a resistor, the pressure level of the exhaust pulsation is reduced by the rectifying action, and the radiated sound from the main muffler 1 is reduced. Will be suppressed.

It is preferable that the diameters of the small holes 33 and 37 are large in order to prevent back pressure. As described above, depending on which of the exhaust noise of the low and medium frequency components and the exhaust noise of the high frequency component is to be reduced. , The diameter and pitch of the small holes 33 and 37 are determined. FIG. 5 is a comparison of the detected value of the discharge sound in the low frequency region between the conventional example in which the metal carrier 31 is not mounted and the present embodiment. The pressure level of the exhaust pulsation is reduced by the rectifying action of the metal carrier 31. It is clear from the experimental data that the exhaust noise of low frequency components is suppressed.

As described above, according to the present embodiment, the metal carrier 31 is connected to the insertion end 21a of the outlet pipe 21.
By rectifying the exhaust pulsation, which is the exhaust noise of low frequency components, by mounting the exhaust pulsation of the low frequency component, the pressure level is reduced and the radiation noise from the main muffler 1 is reduced. It is not necessary to increase the muffler stiffness as a measure against radiation noise, and as a result, the size and simplification of the main muffler 1 can be achieved, and the cost can be reduced.

Further, as described above, according to the present embodiment, by mounting the metal carrier 31 in the exhaust gas flow path, the exhaust noise of high frequency components can be attenuated at the same time. This is advantageous in terms of cost because it can be eliminated or shortened, and if the sound absorbing chamber is not required, there is an advantage that the quality is improved by eliminating the scattering of glass wool and the deterioration of the noise reduction performance as in the related art.

In the above embodiment, the metal carrier 31 is mounted in the outlet pipe 21. However, the metal carrier 31 is mounted in a muffler pipe such as the inlet pipe 19 or the communication pipe 27 instead of the outlet pipe 21. Also, according to these embodiments, the intended purpose can be achieved similarly to the above embodiment.
FIG. 6 shows a muffler for a vehicle according to a second embodiment of the present invention. In FIG. 6, reference numeral 43 denotes a prima muffler mounted on a vehicle exhaust system. Is a single baffle plate 5 inside a cylindrical shell 49 whose both ends are closed by end plates 45 and 47.
The first chamber 53 and the second chamber 55 are divided into two sections by a partition 1.

A perforated pipe 59 having a plurality of small holes 57 formed in the peripheral wall is inserted through both end plates 45 and 47 and the baffle plate 51 and inserted on the central axis of the shell 49. In this embodiment, the metal carrier 31 is mounted in a perforated pipe 59 serving as an exhaust gas passage. As shown in the figure, the small hole 57 is not formed in the peripheral wall of the perforated pipe 59 at the mounting portion of the metal carrier 31, and the first chamber 53 and the second chamber 55 each function independently as a resonance chamber. It is supposed to.

Since the noise reduction device 61 according to the present embodiment is configured as described above, the exhaust noise introduced into the prim muffler 43 through the perforated pipe 59 is transmitted to the first chamber 53 and the second chamber 53 which function as a resonance chamber. Exhaust noise of low and medium frequency components is silenced by the resonance damping action in the chamber 55, and the thin corrugated sheet 35 is formed through the small holes 33 and 37 of the metal carrier 31.
A sound wave is propagated to a cell (exhaust gas passage) 41 between the thin plate 39 and the small holes 33, 3 passing therethrough due to friction between the sound wave oscillating and the thin wave plate 35 and the thin plate 39.
Due to the friction with the wall surface of 7, the sound wave energy of the high frequency component is converted into heat energy, and the sound is silenced.

When the exhaust pulsation generated from the engine passes through the metal carrier 31, the pressure level of the exhaust pulsation is reduced by the rectifying action of the metal carrier 31. Thus, according to the present embodiment, the perforated pipe 5
Exhaust pulsation is rectified by the metal carrier 31 mounted in the gas turbine 9 and its pressure level is reduced. Therefore, as in the first embodiment, measures to radiate noise from the exhaust system can be eliminated or simplified, and costs can be reduced. Become.

Further, by mounting the metal carrier 31 in the exhaust gas flow path as described above, the exhaust noise of high frequency components can be silenced at the same time. Therefore, according to the present embodiment, the conventional sound absorbing chamber is unnecessary. Alternatively, it can be shortened, which is advantageous in terms of cost. If a sound absorbing chamber is not required, there is an advantage that the quality is improved by avoiding the scattering of glass wool and the deterioration of the noise reduction performance as in the related art.

FIG. 7 shows a vehicle silencer according to one of the first, third and fifth embodiments. In the drawing, reference numeral 63 denotes a front tube of a vehicle exhaust system. 65 is characterized in that a metal carrier 67 having a large number of exhaust gas passages and a large number of small holes connected thereto is mounted in the exhaust gas flow path of the front tube 63;
A catalytic converter (not shown) is mounted on the metal carrier 67 on the exhaust gas upstream side.

As shown in FIG. 8, the metal carrier 67 is formed in a thick cylindrical shape in which a thin corrugated plate 71 having a large number of small holes 69 is wound in multiple layers. A large number of cells 73 formed by the corrugated plate 71 function as exhaust gas passages, and the cells 73 are connected to each other by a large number of small holes 69. The thin corrugated sheet 71 is made of SUS304, SUS41, like the thin corrugated sheet 35 described above.
The thickness of the stainless steel foil is set to several tens μm and the diameter of the small hole 71 is set to a range of φ0.5 to φ6. ,
The diameter and pitch of the small holes 71 are determined depending on which one of the exhaust noise of the medium frequency component and the exhaust noise of the high frequency component is given priority.

Since the present embodiment is configured as described above, sound waves emitted from the engine are transmitted to the cells (exhaust gas passages) 73 between the thin corrugated plates 71 through the many small holes 69 of the metal carrier 67. The sound wave energy of the high-frequency component is converted into heat energy by the friction between the propagated and vibrating sound wave and the thin corrugated plate 71 or the wall surface of the small hole 69 passing therethrough, thereby silencing the sound. It will be.

When the exhaust pulsation generated from the engine passes through the metal carrier 67, the pressure level of the exhaust pulsation is reduced by the rectifying action of the metal carrier 67. Therefore, also in the present embodiment, since the exhaust pulsation is reduced by mounting the metal carrier 67 in the exhaust gas flow path of the front tube 63, it is not necessary or simple to take measures against the radiation noise from the exhaust system, and the cost can be reduced. In addition, by mounting the metal carrier 67 in the exhaust gas flow path, the exhaust noise of high frequency components can be silenced at the same time, so that the conventional sound absorbing chamber can be eliminated or shortened, and the cost can be reduced. Advantageously, if the sound absorbing chamber becomes unnecessary, there is an advantage that the quality is improved without scattering of the glass wool and deterioration of the sound deadening performance as in the related art.

In the embodiment shown in FIG. 1, a thin corrugated plate 35 having a large number of small holes 33 and a thin flat plate 39 having a large number of small holes 37 are alternately stacked as shown in FIG. The metal carrier 31 is formed by winding multiple times, and in the embodiment shown in FIG. 7, a thin corrugated plate 71 having a large number of small holes 69 is wound multiple times as shown in FIG. Although it was formed, a large number of small holes may be provided in two types of thin corrugated sheets called so-called "large waves" and "small waves", and these may be wound multiple times to form a metal carrier, Furthermore, the metal carrier is not limited to the wound type as described above,
It may be a laminate of thin corrugated sheets or thin flat plates, or a thin corrugated sheet which is folded in a spell.

In each of the above embodiments, the thin corrugated sheet 3
5,71 and a large number of small holes 33,3 on the entire surface of the thin plate 39.
7 and 69 are provided, but it is not always necessary to provide the metal carrier 67 of FIG. 8 in the outlet pipe 21 in place of the metal carrier 31 of FIG.
The metal carrier 31 of FIG. 2 may be mounted in the front tube 63 instead of the metal carrier 67 of FIG.

[0031]

As described above, according to the vehicle silencer of the present invention, by mounting the metal carrier in the exhaust gas passage of the vehicle exhaust system, the exhaust pulsation is rectified and the vehicle exhaust system is rectified. This reduces the need to increase the capacity of the resonator of the main muffler and increase the muffler rigidity as a countermeasure against radiation noise, which reduces the size and simplification of the main muffler. As a result, costs can be reduced.

Further, according to the muffler according to each claim,
By mounting the metal carrier in the exhaust gas flow path, exhaust noise of high frequency components can be attenuated at the same time, so the conventional sound absorbing chamber can be eliminated or shortened, which is advantageous in cost, and the sound absorbing chamber is unnecessary. Then
There is an advantage that the quality is improved by eliminating the scattering of glass wool and the deterioration of the noise reduction performance as in the related art.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a muffler according to a first embodiment of claims 1, 2 and 4.

FIG. 2 is an overall perspective view of a metal carrier used in the muffler of FIG.

FIG. 3 is a perspective view of a thin corrugated sheet for molding the metal carrier of FIG. 2;

FIG. 4 is a perspective view of a thin plate for forming the metal carrier of FIG. 2;

5 is experimental data comparing the detected values of the ejection noise in the low frequency region between the embodiment shown in FIG. 1 and the conventional example.

FIG. 6 is a sectional view of a muffler according to a second embodiment of the present invention.

FIG. 7 is a cross-sectional view of the muffler according to the first, third, and fifth embodiments.

FIG. 8 is an overall perspective view of a metal carrier used in the noise reduction device of FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main muffler 3, 5, 45, 47 End plate 7, 49 Shell 9, 11, 51 Baffle plate 19 Inlet pipe 21 Outlet pipe 23, 33, 37, 57, 69 Small hole 29, 61, 65 Silencer 31, 67 Metal carrier 35, 71 Thin corrugated plate 39 Thin flat plate 43 Prima muffler 59 Perforated pipe 63 Front tube

Claims (5)

[Claims] An exhaust gas passage of a vehicle exhaust system includes a plurality of exhaust gas passages and a plurality of small holes (33, 37, 6) connected thereto.
A vehicle silencer comprising a metal carrier (31, 67) having 9). 2. The metal carrier (31) has a number of small holes (3).
2. A thin corrugated plate (35) having 3) and a thin flat plate (39) having a large number of small holes (37) are alternately overlapped and wound in a multiplex manner. Vehicle silencer. 3. The metal carrier (67) has a number of small holes (6).
2. The vehicle silencer according to claim 1, wherein the thin corrugated sheet (71) having (9) is wound in multiple layers. 4. A muffler pipe of a muffler (1, 43) mounted on a vehicle exhaust system, wherein the metal carrier (31, 67) is mounted in a muffler pipe.
The vehicle noise reduction device according to any one of claims 1 to 4. 5. The vehicle according to claim 1, wherein the metal carrier (31, 67) is mounted in a front tube (63) of a vehicle exhaust system. Silencer.