JP2004251249A - Silencer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silencer capable of increasing silencing capacity of high frequency component irrespective of limited pipe off set of the silencer. <P>SOLUTION: A plurality of bulkheads 17 are provided inside a main muffler main body 11 to constitute an expansion chamber 18 and a resonance chamber 10. Inlet pipes 12, 13 connecting the expansion chamber 18 with the resonance chamber 19, an inner pipe 14, and an outlet pipe 15 are provided. Many pipe holes 16 communicating the inside with the outside of the pipes are provided in a part of each pipe. A glass wool chamber 2 filled with glass wool 21 inside it is provided. The glass wool chamber 2 is attached to the outlet pipe 15 so as to cover the outer periphery of the pipes in a part where the pipe holes 16 are provided with the glass wool 21. Positions of the pipes are made eccentric for the glass wool 21 in the glass wool chamber 2 to provide difference in thickness of the glass wool 21. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention belongs to the technical field of a muffler for muffling exhaust noise of high frequency components by covering a hole of a pipe connecting a muffler inside a muffler with glass wool.
[0002]
[Prior art]
In a conventional silencer, glass wool is attached to the outer circumference of a muffler pipe such as an inlet pipe or an outlet pipe as a noise reduction measure against exhaust noise of high frequency components (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-9-133014 (pages 2-4, FIG. 1)
[0004]
[Problems to be solved by the invention]
However, in recent years, the capacity of the main muffler has been increased with the improvement in engine power performance and noise reduction performance. Also, in order to secure the capacity of the silencer (muffler) and the ground clearance, the silencer is often flattened, and the amount of offset between the pipes inside the silencer and the pipes is restricted, so it is very difficult to secure the capacity. It's getting harder. When there is a restriction on such a pipe offset, it has been impossible to secure a sufficient thickness of glass wool by using a perfect circular chamber.
[0005]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a muffler that increases the muffling volume of a high-frequency component even with a limited muffler pipe offset.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, in the invention according to claim 1, a plurality of partitions are provided inside the muffler main body to configure a plurality of muffling chambers, a plurality of pipes connecting the muffler chambers are provided, and a pipe A glass wool chamber filled with glass wool is provided inside and a glass wool chamber filled with glass wool is provided. The position of the pipe is eccentric with respect to the glass wool, and the thickness of the glass wool is made different.
[0007]
In the invention according to claim 2, the glass wool chamber is an outlet pipe that discharges exhaust gas from the silencer chamber to the downstream of the silencer main body,
The outlet pipe is decentered vertically with respect to the glass wool in the glass wool chamber.
[0008]
Function and Effect of the Invention
According to the first aspect of the present invention, by giving a difference in the thickness of the glass wool, even if the silencer has a cross-sectional shape with no allowance such as a flat shape, the position of the pipe is eccentric with respect to the glass wool in the glass wool chamber. In addition, the glass wool chamber can be provided with a sufficient thickness to suppress the high frequency component. Therefore, compared to the conventional case in which the diameter of the glass wool chamber is reduced according to the cross-sectional shape having no allowance, the sound volume can be increased.
[0009]
According to the second aspect of the present invention, the high-frequency component of the glass wool is silenced with respect to the exhaust gas immediately before being discharged to the outside of the sound-muffling chamber, and the exhaust gas is exhausted in a state where the high-frequency component in the sound-muffling chamber has a sound-muffling effect thereafter. By making the outlet pipe position eccentric with respect to the glass wool in the glass wool chamber up and down, the glass wool chamber has a thickness that suppresses the high-frequency component even when it is made flat and shorter. Can be.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments for realizing the muffler of the present invention will be described based on embodiments corresponding to the first and second aspects of the present invention.
[0011]
(Example)
[0012]
First, the configuration will be described.
FIG. 1 is a plan view showing the muffler of the embodiment. FIG. 2 is a front view of the muffler of the embodiment. FIG. 3 is a schematic diagram of an exhaust system using the muffler of the embodiment. FIG. 4 is a graph showing the sound deadening effect of the sound deadener of the embodiment. The main reference numerals in FIGS. 1 to 3 are as follows. 1 is a main muffler (muffler), 11 is a main muffler main body (muffler main body), 12 and 13 are inlet pipes (pipe), 14 is an inner pipe (pipe), 15 Is an outlet pipe (pipe), 16 is a pipe hole, 17 is a partition, 18 is an expansion room (muffler room), 19 is a resonance room (muffler room), 2 is a glass wool chamber, 21 is a glass wool, 3 is an engine, 4 is an exhaust Manifold, 5 is a catalytic converter, 6 is a sub-muffler, A is a sound pressure graph curve of a glass wool chamber sized to be accommodated in the main muffler body without eccentricity, B is a sound pressure graph curve of an eccentric glass wool chamber It is.
[0013]
The main muffler 1 of the embodiment is provided downstream of the catalytic converter 5 and the sub-muffler 6 in the exhaust system from the engine 3 as shown in FIG.
This main muffler 1 forms three expansion chambers 18 and one resonance chamber 19 by providing three partition walls 17 inside the main muffler main body 11 as shown in FIGS. Inlet pipes 12 and 13 to be taken in, an inner pipe 14 for communicating between the expansion chamber 18 and the resonance chamber 19, and an outlet pipe 15 for sending exhaust gas from the inside to the downstream are provided. Each pipe is provided with a pipe hole 16 in a predetermined range.
[0014]
The glass wool chamber 2 is provided in the portion of the outlet pipe 15 having the pipe hole 16 located in the resonance chamber 19. Since the inside of the glass wool chamber 2 is filled with the glass wool 21, the outer circumference of the outlet pipe 15 having the pipe hole 16 is covered with the glass wool 21.
In the present embodiment, as shown in FIG. 2, the outlet pipe 15 is eccentric so as to be lowered downward with respect to the glass wool chamber 2 so that the thickness of the glass wool 21 is different between the upper and lower sides.
[0015]
Next, the operation will be described.
[0016]
[Operation to ensure mute volume]
In the present embodiment, the eccentric arrangement allows the glass wool 21 to have a thickness even in the main muffler 1 having a flat cross section as shown in FIG. Conventionally, such a muffler shape has been dealt with by reducing the thickness of the glass wool 21.
The following is a result of a test on a muffler having a flat cross-sectional shape as in the example, in which the outlet pipe 15 is eccentric with respect to the glass wool chamber 2, and the difference in the noise reduction effect between the case where the glass wool 21 is made thinner. Is shown.
[0017]
Evaluation test product: equivalent to this example (glass wool chamber diameter: 110 mm, outlet pipe diameter: 75 mm, pipe offset amount: 27 mm)
[0018]
: Conventional product (glass wool chamber diameter: 96 mm, outlet pipe diameter: 75 mm)
Test conditions: The position where the sound pressure level when the engine speed is changed by the engine bench (or the state of the vehicle) with the exhaust system attached to the engine alone is 50 cm away from the tail end specified by JIS in a direction of 45 °. Measured from
FIG. 4 shows the test results of the tests performed in this manner. A is a sound pressure graph curve of a glass wool chamber sized to be accommodated in the main muffler body without eccentricity, and B is a sound pressure graph curve of an eccentric glass wool chamber. In the range of 3000 rpm or more, the sound pressure level of the exhaust sound is reduced by about 1.5 dB due to the silencing effect of the high frequency component of the glass wool 21.
Therefore, the silencing volume is secured more effectively than before.
[0019]
[Improvement of design flexibility]
By thus eccentrically positioning the outlet pipe 15 with respect to the glass wool chamber 2 to ensure a sound-absorbing volume, a muffler having a cross section that has no margin not only in the vertical direction but also in the left and right directions can be provided. This improves the degree of freedom in designing a muffler that requires a high height. In addition, the degree of freedom in the internal design of the muffler itself is improved.
[0020]
Next, effects will be described.
[0021]
In the muffler according to the embodiment, the following effects can be obtained.
[0022]
(1) A plurality of partitions 17 are provided inside the main muffler main body 11 to form an expansion chamber 18 and a resonance chamber 19, and inlet pipes 12 and 13, an inner pipe 14, and an outlet pipe 15 connecting the expansion chamber 18 and the resonance chamber 19. Is provided, a number of pipe holes 16 are provided in a part of each pipe to communicate the inside and outside of the pipe, a glass wool chamber 2 filled with glass wool 21 is provided therein, and the outer periphery of the pipe where the pipe hole 16 is provided is covered with the glass wool 21. As described above, in the silencer in which the glass wool chamber 2 is attached to the outlet pipe 15, the pipe position is eccentric with respect to the glass wool 21 of the glass wool chamber 2, and the thickness of the glass wool 21 is made different, so that the cross-sectional shape has no margin. Compared to the conventional case where the diameter of the glass wool chamber 2 was reduced, Can be increased, even cross-sectional shape can not afford it to a muffler having a sufficient silencing effect.
In addition, such eccentricity makes it difficult to influence the pipe layout even when the muffler shape is increased in flatness or is irregular, and helps maintain an effective pipe layout. It can also be used to secure the freedom of layout. In addition, clearance can be easily secured.
[0023]
(2) The glass wool chamber 2 is an outlet pipe 15 for discharging exhaust gas from the inside of the muffler main body to the downstream of the outside of the main muffler main body 11, and the position of the outlet pipe 15 is decentered vertically with respect to the glass wool 21 of the glass wool chamber 2. Therefore, even when the glass wool chamber 2 has a flat shape in which the upper and lower portions are shortened, the glass wool chamber 2 can have a thickness for silencing high-frequency components, and the minimum ground clearance required when the glass wool chamber 2 is incorporated in a vehicle can be easily secured.
[0024]
The silencer of the present invention has been described based on the embodiments. However, the specific configuration is not limited to these embodiments, and may deviate from the gist of the invention according to each claim in the claims. Unless otherwise noted, changes and additions to the design are permitted.
For example, in the embodiment, the main muffler is configured by the inlet pipe, the inner pipe, the outlet pipe, the three expansion chambers, and the one resonance chamber. However, another configuration may be adopted.
[Brief description of the drawings]
FIG. 1 is a plan view showing a muffler according to an embodiment.
FIG. 2 is a front view of the muffler of the embodiment.
FIG. 3 is a schematic diagram of an exhaust system using the muffler of the embodiment.
FIG. 4 is a graph showing a sound deadening effect of the sound deadener of the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Main muffler 11 Main muffler main body 12 Inlet pipe 13 Inlet pipe 14 Inner pipe 15 Outlet pipe 16 Pipe hole 17 Partition wall 18 Expansion room 19 Resonance room 2 Glass wool chamber 21 Glass wool 3 Engine 4 Exhaust manifold 5 Catalytic converter 6 Sub muffler

Claims (2)

A plurality of partitions are provided inside the muffler body to form a plurality of muffling chambers, a plurality of pipes connecting the muffler chambers are provided, and a number of pipe holes are provided in a part of the pipes to communicate the inside and outside of the pipes, and glass wool is provided inside. A muffler in which the glass wool chamber is attached to the pipe so as to cover the outer periphery of the pipe provided with the pipe hole with glass wool.
A silencer characterized in that the position of the pipe is eccentric with respect to the glass wool in the glass wool chamber, and the thickness of the glass wool is varied. The muffler according to claim 1,
The glass wool chamber is an outlet pipe that discharges exhaust gas from the silencer to the outside of the silencer body downstream,
A silencer characterized in that an outlet pipe is vertically eccentric with respect to glass wool in a glass wool chamber.

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