JP2952805B2 - Silencer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a muffler having an expansion chamber, an exhaust gas inlet pipe for flowing exhaust gas into the expansion chamber, and an exhaust gas outlet pipe for discharging exhaust gas from the expansion chamber.

[0002]

2. Description of the Related Art Conventionally, a muffler which is provided at an intermediate portion of an exhaust pipe extending from an engine and has a single expansion chamber is provided with an exhaust inflow pipe having an outlet end opened in the expansion chamber. An exhaust outlet pipe having an inlet end opened in the expansion chamber is provided, and the outlet end of the exhaust inlet pipe and the inlet end of the exhaust outlet pipe are arranged so as to face each other on the same axis. Further, as another conventional one, an exhaust pipe penetrating an expansion chamber and having a number of punching holes opened to the expansion chamber is used.

[0003]

In any of the above conventional silencers, since the flow of exhaust gas in the expansion chamber is linear, the exhaust gas does not diffuse sufficiently into the expansion chamber when the exhaust gas flow rate increases. There was a problem that the effect was reduced.

The present invention has been made in view of such circumstances, and it is possible to obtain a sufficient noise reduction effect even if the exhaust flow velocity increases, and to minimize the increase in exhaust resistance. The aim is to provide a possible silencer.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention comprises an expansion chamber, an exhaust inlet pipe for flowing exhaust gas into the expansion chamber, and an exhaust outlet pipe for discharging exhaust gas from the expansion chamber. In the muffler, the outlet end of the exhaust inflow pipe and the inlet end of the exhaust outflow pipe are opened in opposite directions in the expansion chamber, and the inlet end of the exhaust outflow pipe has a forward end.
A tapered diameter expanding portion is formed, and one of the diameter expanding portions is formed.
The recessed portion and the outer periphery of the exhaust inflow pipe are brought into surface contact with each other and are coupled.

[0006]

According to the above construction, the exhaust gas flowing into the expansion chamber from the outlet end of the exhaust inflow pipe rotates in a loop along the inner wall surface of the expansion chamber and reaches the inlet end of the exhaust outflow pipe. It is discharged from the expansion chamber via the outflow pipe. Even if the exhaust gas flow rate increases, the exhaust gas circulates smoothly in the expansion chamber without short-circuiting, so that the noise reduction effect is ensured and the increase in exhaust resistance is minimized. Further, since the exhaust inlet pipe and the exhaust outlet pipe are connected to each other, the rigidity of the silencer is improved without special reinforcement. Also open in the expansion chamber
Exhaust outlet pipe inlet end tapered forward
Because the diameter is enlarged, the exhaust gas in the expansion chamber is
The exhaust resistance at the exhaust outlet pipe
It is possible to decrease and increase the output of the engine. Also exhaust
Concave part with concave part of tapered enlarged part of outflow pipe and exhaust
The outer periphery of the inflow pipe can be connected by surface contact.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 7 show a first embodiment of the present invention. FIG. 1 is an overall plan view of a vehicle, FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 1, and FIG. FIG. 4 is a sectional view taken along line 3-3 in FIG.
FIG. 5 is an enlarged sectional view taken along line 5-4 of FIG.
6 is a sectional view taken along line 6-6 of FIG. 5, and FIG. 7 is an enlarged sectional view taken along line 7-7 of FIG.

As shown in FIG. 1, an exhaust device 3 is connected via a flexible joint 2 to a rear end of an exhaust manifold 1 of an engine E mounted on a front portion of a front wheel drive vehicle V. The exhaust device 3 is disposed in the front-rear direction along the lower surface of the vehicle body, and includes a first exhaust pipe 4 connected to the flexible joint 2, an exhaust gas purification catalyst 5 connected to the first exhaust pipe 4, and an exhaust gas. The second connected to the purification catalyst 5
An exhaust pipe 6, a third exhaust pipe 7, a sub-muffler 8 connected to the third exhaust pipe 7, and a fourth exhaust pipe 10 connected to the sub-muffler 8 and arranged below the fuel tank 9. , Fourth exhaust pipe 1
The main silencer 11 is connected to the main muffler 11, the tail pipe 12 is connected to the main muffler 11, and the diffuser 13 is connected to the tail pipe 12.

Next, the structure of the sub silencer 8 will be described with reference to FIGS.

Inside the sub-muffler 8, a front end plate 22 and a rear end plate 23 are welded to front and rear openings of a muffler body 21 having an elliptical cross section, respectively, and a partition plate is provided inside the muffler body 21. By welding 24, a first expansion resonance chamber 25 having a relatively small volume and a second expansion resonance chamber 26 having a relatively large volume are formed.

An exhaust inflow pipe 27 penetrates the front end plate 22 and the partition plate 24 back and forth, and the front end of the exhaust inflow pipe 27 is welded to the front end plate 22 and the rear end of the third exhaust pipe 7. At the same time, the rear end of the exhaust inflow pipe 27 is welded to the partition plate 24. The first expansion resonance chamber 25 is provided in the exhaust inflow pipe 27.
Are formed in a plurality of punching holes 27 ₁ .

Exhaust outlet pipe 28 fitted to rear end plate 23
Is welded to the rear end plate 23 and the front end of the fourth exhaust pipe 10. A rear end of the exhaust inflow pipe 27 extending into the second expansion resonance chamber 26 and a front end of the exhaust outflow pipe 28 are welded to a front end and a rear end of the S-shaped connecting pipe 29, respectively. Connecting pipe 29 is divided into the upper half body 29 ₁ and the lower half 29 ₂ a plane including its axis, Ryohantai 29 _1, 29
₂ is welded together at its flange. A large number of punching holes 28 ₁ communicating with the second expansion resonance chamber 26 are formed in the exhaust outlet pipe 28.

Next, the main silencer 11 will be described with reference to FIGS.
The structure of will be described.

Inside the main silencer 11, a front end plate 31 and a rear end plate 32 are welded to front and rear openings of a silencer body 30 having an elliptical cross section, respectively, to thereby form a single expansion chamber 33.
Is formed.

Exhaust inflow pipe 34 fitted to front end plate 31
Is welded to the front end plate 31 and the rear end of the fourth exhaust pipe 10. Exhaust outlet pipe 35 fitted to rear end plate 32
Is welded to the rear end plate 32 and the front end of the tail pipe 12. The outlet end 3 of the exhaust inflow pipe 34 that extends to the middle part in the front-rear direction of the expansion chamber 33 and opens rearward.
4 _1, the distance from the inlet end 35 ₁ of the exhaust outlet pipe 35 which opens toward the front extends up to the front end close to the expansion chamber 33 A
And the exhaust inflow pipe 34
And the exhaust pipe 35 are integrally welded.

[0017] That is, the inlet end 35 ₁ near the exhaust outlet pipe 35, the enlarged diameter portion 3 whose diameter increases in a tapered shape toward the front
5 ₂ is formed, the enlarged diameter portion 35 ₂ of the recess 35 ₃ where the recessed arcuately part exhaust inlet pipe (see FIG. 5) 34
Outlet end 34 ₁ near the fits. Therefore, the outer periphery and the outer periphery of the exhaust outlet pipe 35 of the distance A ₁ of the exhaust inlet pipe 34 in the range is welded in line contact, the outer periphery and the recesses of the exhaust outlet pipe 35 of the exhaust inlet pipe 34 in a range of the distance A ₂ 35 ₃ is welded in surface contact.

The diffuser 13 welded to the rear end of the tail pipe 12 has a double structure having an inner wall 38 and an outer wall 39, and a glass wool 41 between the inner wall 38 and the outer wall 39 is filled with glass wool 41. The inner wall 38 of the diffuser 13 expands in a tapered shape toward the rear, and a number of punching holes 38 ₁ communicating with the glass wool storage chamber 40 between the inner wall 38 and the outer wall 39 are formed.

Thus, the first and second expansion resonance chambers 25, 26
The sub-muffler 8 (volume 6 liters), which has a small volume, mainly attenuates medium and high frequency exhaust noise, and the main silencer 11 (volume 13 liters), which has a large volume, has low volume.
Attenuation of the medium frequency exhaust noise is performed. Like this,
The attenuation of high frequency exhaust noise is shared by the auxiliary silencer 8
By sharing the attenuation of the medium frequency exhaust noise to the main silencer 11, the complexity of the internal structure of the silencer required when a single silencer attenuates the exhaust noise of all frequency bands is eliminated. This can contribute to cost reduction. Especially,
Main silencer 11 for sharing low and medium frequency exhaust noise attenuation
Can have a single-chamber structure having a single expansion chamber 33, so that the effect of attenuating low-frequency exhaust noise can be improved and the number of parts can be reduced.

In the main silencer 11, the outlet end 34 ₁ of the exhaust inflow pipe 34 opening rearward and the inlet end 35 ₁ of the exhaust outflow pipe 35 opening forward are mutually connected. Due to the superposition, even if the exhaust gas flow rate increases, the exhaust gas does not short-circuit from the exhaust inflow pipe 34 to the exhaust outflow pipe 35, and the expansion chamber 33 as shown by an arrow in FIG.
Rotates along the inner wall of the. As a result, even if the exhaust flow velocity increases, not only a sufficient silencing effect can be obtained, but also the expansion chamber 33
By smoothly circulating exhaust gas inside the engine, it is possible to minimize an increase in exhaust resistance and avoid a decrease in the output of the engine E. Moreover, since the exhaust inflow pipe 34 and the exhaust outflow pipe 35 are integrated by welding inside the expansion chamber 33, the rigidity against the bending moment applied from the fourth exhaust pipe 10 and the tail pipe 12 is increased by the welded portion. Can be increased.

Further, an opening is provided in the expansion chamber 33 of the main silencer 11.
End 35 of Exhaust Outflow Pipe 35 ₁Is facing forward
The exhaust inside the expansion chamber 33 is exhausted because
It can be guided smoothly to the air outflow pipe 35. Again
Tail pipe 1 extending rearward from expansion chamber 33 of sound device 11
2 rearward the inner wall 38 of the diffuser 13 provided at the rear end.
The diameter of the diffuser is
3 prevents the generation of eddy currents and smooth exhaust
Can be discharged. Thus, the exhaust outlet pipe 35 and
The exhaust resistance at the tail pipe 12 is reduced and the exhaust flow rate is reduced.
And the output of the engine E can be increased.

As described above, when the flow rate of exhaust gas increases, high-frequency airflow noise is likely to be generated in the diffuser 13. However, the airflow noise can be reduced by the glass wool 41 stored in the glass wool storage chamber 40 of the diffuser 13. Moreover, the tail pipe 12 that can be seen from outside
By providing the diffuser 13 at the rear end, it is possible to improve the aesthetic appearance.

According to the exhaust device 3 of the present embodiment,
The exhaust noise in the muffled sound range of the engine speed from 1500 rpm to 4500 rpm was greatly reduced, and the exhaust flow rate was increased by 3 liters per second, thereby achieving an output improvement equivalent to 1.5 horsepower.

Although the embodiments of the present invention have been described in detail, various design changes can be made in the present invention without departing from the gist thereof.

For example, in the embodiment, the main silencer 11 has one exhaust outlet pipe 35, but as shown in the second embodiment of FIG. 8, two exhaust outlet pipes 35 are provided. Is also possible. Further, the exhaust inflow pipe 34 and the exhaust outflow pipe 35 can be integrated by any means other than welding.

[0026]

As described above, according to the present invention, the outlet end of the exhaust inflow pipe and the inlet end of the exhaust outflow pipe are opened in the expansion chamber in opposite directions to each other. Since the outlet end and the inlet end of the exhaust outlet pipe are overlapped and connected to each other, the exhaust gas flowing into the expansion chamber from the outlet end of the exhaust inlet pipe is smoothly circulated without short-circuiting inside the expansion chamber. Then, it is possible to guide the exhaust gas to the inlet end of the exhaust outlet pipe, thereby improving the noise reduction effect and reducing the exhaust resistance. Further, since the exhaust inflow pipe and the exhaust outflow pipe are mutually connected, the rigidity of the muffler can be improved without special reinforcement. Also inflated
The inlet end of the exhaust outlet pipe that opens into the room faces forward.
The expansion inside the expansion chamber
Can be guided smoothly to the outlet pipe,
Reduced exhaust resistance and increased engine output
You. Also, depress a part of the tapered enlarged part of the exhaust outlet pipe.
The concave recess and the outer circumference of the exhaust
Can be.

[Brief description of the drawings]

FIG. 1 is an overall plan view of a vehicle.

FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is a sectional view taken along line 4-4 in FIG. 3;

FIG. 5 is an enlarged sectional view taken along line 5-5 of FIG. 1;

FIG. 6 is a sectional view taken along line 6-6 in FIG. 5;

FIG. 7 is an enlarged sectional view taken along line 7-7 of FIG. 1;

FIG. 8 is a view according to a second embodiment and corresponding to FIG. 6;

[Explanation of symbols]

33 Expansion chamber 34 Exhaust inflow pipe 34 ₁ Outlet end 35 Exhaust outflow pipe 35 ₁ Inlet end

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F01N 1/08

Claims (1)

(57) [Claims] An expansion chamber (33), an exhaust gas inflow pipe (34) for flowing exhaust gas into the expansion chamber (33), and an expansion chamber (33).
And an exhaust outlet pipe (35) for exhausting exhaust gas from the exhaust end (3) in the expansion chamber (33).
4 ₁ ) and the inlet end (35 ₁ ) of the exhaust outlet pipe (35) are opened in opposite directions to each other , and the exhaust outlet pipe (35) is opened .
At the entrance end (35 ₁ ), taper forward
An enlarged diameter portion (35 ₂ ) for increasing the diameter is formed, and the enlarged diameter portion (35 ₂ ) is formed.
₂ ) Part of the recess (35 ₃ ) and the exhaust inflow pipe (3)
4) A silencer characterized in that the outer periphery of the silencer is joined to the outer periphery by surface contact .