JP3337556B2 - Silencer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust muffler for an automobile.

[0002]

2. Description of the Related Art As shown in FIG. 2, the basic types of exhaust silencers for automobiles are (a) extended type, (b), (b ') extended resonant type, (c) resonant type, and (d) absorption type. , (E) interference type,
(F) It can be classified into a resistance type or the like.

The expansion type is a hollow cylindrical silencer as shown in FIG. 2 (a). Exhaust gas entering from the left side of the figure suddenly expands in the hollow cylinder and the pressure is reduced, and at the same time both walls are reduced. Sound waves are reflected from and interfere with each other to reduce sound.

In the extended resonance type, as shown in FIG. 2 (b), a pipe penetrates through a hollow cylinder and a part of the pipe is cut off. Accordingly, the exhaust gas expands on the way through the pipe, rushes toward the walls on both sides, and interferes with the reflected waves to reduce the sound. The same effect can be obtained by providing a large number of holes in the middle of the pipe as shown in FIG. 2 (b ') instead of cutting off the middle of the penetrating pipe.

In the resonance type, a resonator having a certain volume is attached beside the exhaust pipe as shown in FIG. 2C, and absorbs sound having the same frequency as the natural frequency of the resonator. Things.

In the absorption type, as shown in FIG. 2D, a large number of holes are provided in an exhaust pipe penetrating the inside of the cylinder, and a sound absorbing material such as glass wool is wound therearound. It gushes and absorbs sound while repeating reflection and interference while passing through glass wool.

In the interference type, as shown in FIG. 2 (e), a bypass is provided in the exhaust pipe. The length of the two pipes is set to be different, and the phase of the sound is half at the point where they merge. The sound is reduced by interfering with each other by shifting by the wavelength.

As shown in FIG. 2 (f), the resistance type is such that a part of an exhaust pipe is made thin, and resistance is added when exhaust gas passes to suppress propagation of sound vibration.

As the performance of automobiles improves, the number of revolutions of the engine often increases to 5,000 rpm or more. Therefore, there is a need for a silencer that has low exhaust resistance and can withstand high temperatures.
Further, with the change of the catalyst from the measure of environmental pollution of exhaust gas, a material having high rust-proof property is used.

A typical silencer in practical use is shown in FIG.
As shown in (1), the cylinder is partitioned into three empty chambers to form an expansion chamber and a resonance chamber, respectively, and these chambers are connected by a cervix.
The exhaust gas enters from the left side of the figure and expands to reduce the pressure, but the sound is attenuated due to resonance with the resonance chamber. It is compressed and expanded again and released into the atmosphere. This method combines the above-mentioned extended resonance type, interference type, resistance type, and the like. However, since the exhaust gas travels while colliding with the partition wall and colliding with the reflected wave, when the engine speed is increased, the flow of the exhaust gas becomes worse and the back pressure is increased.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a silencer which makes the flow of exhaust air one-way, and performs expansion, compression, interference and the like in the middle of the flow to effectively muffle the sound. It is.

[0012]

According to the present invention, at least two chambers are provided by dividing a cylindrical chamber by a spiral partition, and exhaust pipes having different ignition orders are provided to the two chambers. Is connected, the pressure on one side of the chamber is set to a negative pressure, thereby increasing the exhaust speed. Further, preferably, a large number of holes are provided in the partition wall to diffuse exhaust pressure, and furthermore, a partition wall having an opposite twist direction is provided in a part to reduce vortices of the exhaust flow and absorb noise.

[0013]

Embodiment 1 FIG. 1 is a perspective view showing an embodiment of a muffler according to the present invention. In the figure, the cylindrical portion is shown in perspective. A cylinder 2 constituting the silencer 1 and two exhaust inlet pipes 4 at one end thereof.
1, 4-2 are connected, and the internal space of the cylinder 2 is divided by the partition plate 3, and the exhaust gas is led to the inlet of the cylinder while being separated into two systems. Further, the two exhaust inlet pipes are, for example, in the case of a four-cylinder engine.
Then, the exhaust manifold is connected to the and exhaust pipes, and the exhaust pipes are combined into two exhaust pipes and joined to the exhaust inlet pipes 4-1 and 4-2, respectively.

FIG. 2 shows a state in which the spiral partition wall 5 makes one rotation while advancing clockwise in contact with the inner surface of the cylinder 2. This is a shape obtained by twisting a so-called rectangular plate by one turn. Also, a number of holes 6 are provided at the edge of the spiral partition to receive the diffusion of exhaust gas. A spiral partition 7 is provided behind the spiral partition 5 for a half turn while traveling counterclockwise. The other end of the cylinder 2 is connected to an exhaust outlet pipe 8.

When the exhaust gas 9 indicated by dots flows into the exhaust inlet pipe 4-1, the exhaust gas 9 proceeds along one surface of the spiral partition plate 5. The chamber 10 and the chamber 11 partitioned by the spiral partition 5 have a form in which a portion where exhaust gas exists and a portion where no exhaust gas exists alternately exist. In this situation, the correlation between the chamber 10 and the chamber 11 is, of course, because the chamber 10 has a high temperature and a high pressure, the exhaust gas 9 diffuses through the hole 6 and a part of the exhaust gas 9 flows into the chamber 11. Most of the exhaust gas travels while rotating along the spiral partition wall 5.
The resistance is reduced by the inner wall and the spiral partition 5 to reduce the flow velocity. At this time, a point to be noted is that a component that goes round and round along the spiral partition 5 and a component that goes straight through the hole are generated. That is.

As the exhaust gas progresses and makes one rotation along the spiral partition 5, it reaches the counterclockwise spiral partition plate 7 provided at the rear. The ends 5-1 and 7-1 of the spiral partition are in contact with each other at an angle θ degrees. In the present embodiment, θ is 9
0 degrees. The exhaust gas flowing along the spiral partition 5 is supplied to the end 7.
At -1, it is divided into two parts and expands over the entire surface of the cylinder 2 to reduce the exhaust pressure and reduce the vortex of the exhaust flow.

In order to reduce the exhaust pressure and the sound pressure, expansion, compression, interference, and the like may be repeated. In order to perform the compression effectively, the problem is solved by partially shortening the spiral pitch of the spiral partition. ing. In this embodiment, the number of rotations of the spiral partition is set to 1 and the number of chambers formed by the spiral partition is set to 2. However, the present invention is not limited to this.

Next, a case where exhaust gas whose ignition sequence is delayed flows into the exhaust inlet pipe 4-2 will be described. Although the flow of the exhaust gas is a pulsating wave, the exhaust gas 9 that has flowed in first flows into the helical chamber of another system so as to follow the exhaust gas 9 that flowed in a little time difference. In this case, since a negative pressure portion is generated immediately after the exhaust gas 9 passes as a pulsating wave, a high-temperature high-pressure system and a negative-pressure system exist on one side with the spiral partition wall 5 as a boundary surface. Therefore, the exhaust pulsation wave flowing into the exhaust inlet pipe 4-2 is not hindered from proceeding, but rather is accelerated. Thereafter, the exhaust gas silencing effect is guided to the exhaust outlet pipe 8 following the same course as described above.
Therefore, the high pressure portion and the negative pressure portion of the exhaust gas interfere with each other, and the exhaust gas discharged from the exhaust outlet pipe is discharged into the atmosphere as a smooth airflow.

[0019]

According to the present invention, the internal space of the cylinder forming the silencer is divided by a spiral partition so that the exhaust is not reflected, and the resistance, expansion and interference of the exhaust during the continuous flow are reduced. , Which reduces the exhaust pressure and pulsation to rectify the pulsation, thereby reducing the sound pressure. A great silencing effect is obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a muffler according to the present invention.

FIGS. 2 (a), (b), (b '), (c), (d),
(E), (f) is schematic sectional drawing which shows the basic structure of a silencer.

FIG. 3 is a schematic cross-sectional view of a silencer provided for practical use.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 muffler 2 cylinder 3 partition plate 4-1, 4-2 exhaust inlet pipe 5 spiral partition 6 hole 7 spiral partition 8 exhaust outlet pipe 9 exhaust 10, 11 chamber

Claims (3)

(57) [Claims] 1. A large number of holes are provided in the internal space of a silencer cylinder.
At least two chambers are provided divided by a spiral partition having the same, and exhaust pipes having different ignition orders are connected to each of the chambers.
And the exhaust does not flow in from the chamber on one side
Muffler diffused through the hole into the chamber on the side of the muffler. 2. The device according to claim 2, wherein the helical pitch of the chamber is partly shortened.
The silencer according to claim 1, wherein the silencer is compressed . 3. A predetermined angle end of the helical thread of the partition plate that curved in the Re direction clockwise and counterclockwise direction of the partition plate
θ and attach it to the silencer cylinder and place it in the chamber on one side.
Exhaust flowing from the end of the partition plate in different directions of twist
It is characterized by dividing and expanding the exhaust over the entire surface inside the cylinder
Silencer according to any one of claims 1 or claim 2,.