JP2002070524A - Catalyst muffler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst muffler capable of obtaining a muffling effect over the wide frequency range with an outlet muffling chamber. SOLUTION: This catalyst muffler 20 has a catalyst part 21 in the center and an inlet muffling chamber 24 and an outlet muffling chamber 25 installed in an inlet and an outlet through an inlet space part 22 and an outlet space part 23, and the inlet muffling chamber 24 is formed by installing an exhaust inflow pipe 31 having an exhaust port 30 installed between a first end wall 27 blocking one end of a cylindrical shell 26 and a first partition wall 29 having a passing port 28, and the outlet muffling chamber 23 is formed by installing a third partition wall 37 having a second end wall 33 blocking the other end of the cylindrical shell 32, a second partition wall 35 fixing a muffling pipe 34, and a passing port 36, and a long muffling pipe 38 and a short muffling pipe 39 are fixed to between the second partition wall 35 and the third partition wall 37, and an exhaust pipe 41 having outlet holes is installed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As a conventional catalyst muffler, for example, there is one as shown in FIG. In the catalyst muffler 6 shown in the figure, a catalyst section 1 is provided at the center, and an inlet muffler 4 and an outlet muffler 5 are provided via an inlet space 2 and an outlet space 3. Provides an exhaust inlet pipe 12 having an outlet 11 between a first end wall 8 closing one end of a cylindrical shell 7 and a first partition wall 10 having a passage 9, while the outlet silencer 5 is End wall 13 for closing the other end of the shell 7
And a second partition wall 15 for mounting the muffler tube 14, several muffler tubes 14 of the same length are attached to the second partition wall 15, and a discharge pipe 17 having an inlet hole 16 is provided.

[0003]

However, there are actually the following technical problems. That is, in the above-described conventional catalyst muffler, since the plurality of mufflers attached to the exit muffler chamber, in which the muffling effect is remarkable, have the same length, only muffling for noise of a specific frequency can be obtained, and a wide range is obtained. There is a problem that the silencing effect on the frequency is insufficient.

The length of a conventional muffler is at most 1 m or less. With such a size, even if an attempt is made to reduce muffler noise using interference, the phase difference is 1 m and the temperature is 50 m.
The frequency that can be silenced at about 0 ° C. is about 280 Hz, and does not reach the muffling range of the explosion primary component having a high noise contribution rate. In particular, in a catalyst muffler in which a catalyst is disposed in a muffler body, noise reduction using interference is further restricted as compared with a conventional muffler.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a catalyst muffler capable of obtaining a noise reduction effect over a wide frequency range, particularly in an explosive component frequency range, by an outlet noise reduction chamber. is there.

[0006]

In order to achieve the above object, a catalyst muffler according to a first aspect of the present invention is provided with a catalyst section in the center, and an inlet space section and an inlet space section at an inlet side and an outlet side of the catalyst section, respectively. In a catalyst muffler provided with an inlet silencer and an outlet silencer via an outlet space, the inlet silencer or the outlet silencer has a long silencer and a short silencer attached to a partition wall closing a cylindrical shell. It is characterized by becoming. The number of long silence tubes and short silence tubes may be singular or plural. According to the above configuration, the outlet-side silencing chamber is provided with a second end wall closing the other end of the cylindrical shell, a second dividing wall for attaching the silencing tube, and a third dividing wall having a passage opening, and the silencing tube is provided. Since the muffler tubes having different lengths are mounted between the second partition wall to be mounted and the third partition wall having the passage opening, noises of different frequencies can be reduced and a wide range of sound can be muffled.

In the catalyst muffler according to a second aspect of the present invention, a catalyst section is provided in the center, and an inlet silencer and an outlet silencer are provided on the inlet side and the outlet side of the catalyst section via an inlet space and an outlet space, respectively. In the catalyst muffler, the inlet silencer or the outlet silencer is characterized in that a long silencer is attached to a partition wall closing a cylindrical shell and a hole is formed. The number of holes may be singular or plural. ADVANTAGE OF THE INVENTION According to this invention, a structure is simple and the noise of a different frequency can be reduced, and a wide sound range can be silenced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first preferred embodiment of the present invention will be described in detail with reference to FIG. As shown in the drawing, the catalyst muffler 20 has a catalyst section 21 in the center, and has an inlet silencer via an inlet space section 22 and an outlet space section 23 on the inlet side and the outlet side of the catalyst section 21 respectively. A chamber 24 and an exit silencer 25 are provided.

The inlet silencer 24 has a first end wall 27 for closing one end of a cylindrical shell 26 and a first partition wall 29 for partitioning the inlet silencer 24 and the inlet space 22 and having a passage 28.
An exhaust inflow pipe 31 having a plurality of outlets 30 that open to the inlet silencer 24 around the first end wall 27 and is provided with the end face abutting against the first partition wall 29. Become.

On the other hand, the outlet silencing chamber 25 is provided with a cylindrical shell 3.
A second end wall 33 that closes the other end of the second end wall, a second partition wall 35 that divides the outlet space 23 and the outlet muffler chamber 25, and through which a plurality of mufflers 34 penetrates, and a second end wall 33; A third partition wall 37 provided between the second partition walls 35 and made of a perforated plate. For example, four silencers 34 are provided concentrically at equal angular intervals, and all ends thereof are provided at the outlet space 2.
3, the other end of which has a long sound deadening tube 38 (e.g., one located at the bottom in FIG. 1) abutted against the second end wall 33, and a short sound deadening tube 39 (e.g., located at the top in FIG. 1). Is closed on the third partition wall 37. A passage port 36 is formed at an appropriate position on the third partition wall 37.

The long sound deadening tube 38 has a length approximately twice that of the short sound deadening tube 39 (the length of the short sound deadening tube 39 is １ ／ of that of the long sound deadening tube 38).
長), the long sound deadening tube 38 has a plurality of openings communicating with the space between the second end wall 33 and the third partitioning wall 37, and the short sound deadening tube 39 has the second sound deadening tube 39. And a plurality of openings communicating with a space between the third partition walls 35 and 37. A discharge pipe 41 is provided so as to penetrate the third partition wall 37 and the second end wall 33 so that the end face abuts on the second partition wall 35, and the discharge pipe 41 is formed of the second and third partition walls 35 and 37.
Has a plurality of openings communicating with the space between the two.

In the above configuration, the exhaust gas accompanied by noise discharged from the engine is discharged from the exhaust inlet pipe 31 to the outlet 3.
When the vehicle enters the inlet muffling chamber 24 through 0, the muffling is performed by a muffling effect such as resonance or expansion, and the sound enters the entrance space 22 through the passage 28 of the first partition wall 29. The flow of the exhaust gas that has become substantially uniform in the inlet space 22 is purified by the catalyst of the catalyst unit 21, passes through the outlet space 23, passes through the long muffler tube 38 or the short muffler tube 39 of the outlet muffler 25, By changing the propagation distance of the sound wave when releasing the air from the discharge pipe 41 having the outlet hole 40 into the atmosphere, the vibration phase can be shifted and the sound can be silenced. In particular, the noise can be reduced even at a low frequency. it can.

3 and 4 show the results of experiments on the engine.
FIG. 3 shows the relationship between frequency and noise level, and FIG. 4 shows the relationship between engine speed and noise level. As is clear from FIG. 3, it is shown that the noise level of the product of the present invention is lower than that of the conventional product in the low frequency range around the frequency of 70 Hz to 200 Hz. It is shown that the product of the present invention has a better noise level than the conventional product.

Next, a second preferred embodiment of the present invention will be described in detail with reference to FIG. However, portions substantially the same as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In the present embodiment, a plurality of (preferably many) holes 42 and 43 having different sizes are formed in the second partition wall 35 instead of attaching the short muffler tube 39 to the second partition wall 35. , 43 to the exit muffling chamber 25, the wide range of sound can be muffled by utilizing the difference in muffling effect due to the difference in the way of expansion.

In each of the above embodiments, the long sound deadening tube 38
It is preferable that the number of openings formed in the short muffler tube 39 is large, and the total area of the openings formed in the long muffler tube 38 is the same as the total area of the openings formed in the short muffler tube 39. It is desirable.

[0016]

As described above, according to the present invention,
Since the inlet silencer or the outlet silencer consists of a long silencer and a short silencer attached to a partition that closes off the cylindrical shell,
By changing the propagation distance of the sound wave, the vibration phase can be shifted to muffle the sound. According to another aspect of the present invention, since the long silencer is attached to the partition wall that closes the cylindrical shell and the hole is formed, the above-described effects can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a catalyst muffler according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a catalyst muffler according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a graph of an experimental result using the catalyst muffler of the first embodiment.

FIG. 4 is a diagram showing a graph of an experimental result using the catalyst muffler of the first embodiment.

FIG. 5 is a cross-sectional view of a conventional catalyst muffler.

[Explanation of symbols]

 21 Catalyst section 24 Inlet silencer chamber 25 Outlet silencer chamber 32 Shell 33 Second end wall 35 Second partition wall 36 Passage port 37 Third partition wall 38 Long muffler tube 39 Short muffler tube 40 Exit hole 41 Discharge tube

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G004 AA01 BA06 CA06 DA09 3G091 AA02 AB01 BA00 GA06 HA05 HB01

Claims (2)

[Claims] 1. A catalyst muffler having a catalyst section in the center and an inlet silencer and an outlet silencer provided at an inlet side and an outlet side of the catalyst section via an inlet space and an outlet space, respectively. A catalyst muffler characterized in that the chamber or the outlet silencer comprises a long silencer and a short silencer attached to a partition wall closing a cylindrical shell. 2. A catalyst muffler in which a catalyst section is provided in the center and an inlet silencer and an outlet silencer are provided at an inlet side and an outlet side of the catalyst section via an inlet space and an outlet space, respectively. A catalyst muffler characterized in that the chamber or the outlet silencer has a long silencer tube attached to a partition wall closing a cylindrical shell and a hole is formed.