JPH10252443A - Exhaust muffler with control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the appearance of an exhaust muffler with control valve and ensure high output performance by using a doughnutlike space between a small diameter tail tube and a large diameter tail tube as an exhaust gas passage and providing a control valve which is opened and closed by a cylinder type actuator in opening part at a tip of the small diameter tail tube. SOLUTION: A doughnutlike space 15 formed between a small diameter tail tube 5 which is connected to a rear end plate 3 of a muffler main body 1 and has many small holes 5a and a large diameter tail tube 6 provided at an outer peripheral position of the small diameter tail tube 5 in a coaxial condition is used as an exhaust gas passage. A control valve 10 which is opened and closed by a cylinder type actuator 9 which changes a degree of opening of the valve in a stepless manner due to the size of a piston stroke which corresponds to a level of exhaust pressure introduced from a pressure conducting pipe 8 is arranged at an opening position of a tip of the small diameter tail tube 5. According to this muffler, it is possible to obtain high output performance which is equal to that of a sport muffler and the noise reduction performance which is equal to that of a control type muffler due to a dual tail simultaneously.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of an exhaust muffler with a control valve applied to an engine exhaust system of an automobile.

[0002]

2. Description of the Related Art Conventionally, as an exhaust muffler with a control valve, for example, the one described in Japanese Patent Application Laid-Open No. Sho 60-60709 is known.

In this publication, a control tail pipe 4 and a tail pipe 7 are connected to a rear end plate of a muffler main body. The control tail pipe 4 is provided with a control valve that opens in a high engine speed range, and is provided in a low speed range. It describes an exhaust muffler with a control valve that achieves quietness at high speeds and improved output in the middle and high speed regions.

[0004]

However, the conventional exhaust muffler with a control valve described above requires two independent tail pipes 4 and 7 as tail pipes connected to the rear end plate of the muffler body. Therefore, as seen in a sports muffler, there is a problem that even if an attempt is made to increase the diameter of the tail pipe, the two pipes 4 and 7 interfere with each other, making it difficult to increase the diameter of the tail pipe.

On the other hand, as a sports muffler with a large tail tube diameter, for example, Japanese Utility Model Registration No. 30
Japanese Patent No. 20318 and Utility Model Registration No. 301358 are known.

However, unlike the exhaust muffler with a control valve, these sports mufflers can exhibit only a single exhaust function mainly aimed at improving the engine output, so that muffled noise in a low frequency range is generated. It becomes bigger and gives discomfort to drivers and occupants.

An object of the present invention is to provide a control valve having a large diameter tail tube which has the same silencing performance as a control type muffler using a dual tail, and has the same high output performance as a sports muffler. The present invention provides an exhaust muffler equipped with the same.

[0008]

[Means for Solving the Problems]

(Solution 1) An exhaust muffler with a control valve according to a first solution of the above-mentioned problem (Claim 1) is connected to a rear end plate of a muffler main body and has a small-diameter tail tube having a large number of small holes,
A large-diameter tail tube installed coaxially at the outer peripheral position of the small-diameter tail tube and having a donut-shaped space formed between the small-diameter tail tube as an exhaust gas passage, and a tip opening of the small-diameter tail tube A control valve that is arranged at a position and is controlled to be opened and closed by a cylinder-type actuator that changes the valve opening in a stepless manner according to the size of a piston stroke according to the exhaust pressure level introduced from the pressure conduit. Features.

(Solution 2) In the exhaust muffler with a control valve according to claim 1, only the small-diameter tail tube is connected to a rear end plate of the muffler body. The large-diameter tail tube has a single-tube structure fixed to the base end of the small-diameter tail tube, and a tail plate is provided at the open end of the large-diameter tail tube and the open end of the small-diameter tail tube. It is characterized by many small holes.

(Solution 3) In the exhaust muffler with a control valve according to claim 1, only the small-diameter tail tube is connected to a rear end plate of the muffler main body. The large diameter tail tube has a single tube structure fixed to the base end of the small diameter tail tube.

(Solution 4) In the exhaust muffler with a control valve according to the invention, the small-diameter tail tube and the large-diameter tail tube are both rear ends of the muffler body. A dual tube structure connected to a plate, a tail plate is provided at an open end of the large-diameter tail tube and an open end of the small-diameter tail tube, and a large number of small holes are formed in the tail plate. .

(Solution 5) In the exhaust muffler with a control valve according to the invention, the small-diameter tail tube and the large-diameter tail tube are both rear ends of the muffler main body. It has a dual tube structure connected to a plate.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) Embodiment 1 is an exhaust muffler with a control valve according to the first and second aspects of the present invention.

First, the configuration will be described.

FIG. 1 is an overall perspective view showing an exhaust muffler with a control valve according to a first embodiment, FIG. 2 is a view of the exhaust muffler with a control valve according to the first embodiment viewed from the rear, and FIG. 3 is a first embodiment.
FIG. 4 is a sectional view showing a tail tube portion of the exhaust muffler with a control valve of FIG.

1 to 3, reference numeral 1 denotes a muffler body, 2
Is a front end plate, 3 is a rear end plate, 4 is a muffler inlet tube, 5 is a small diameter tail tube, 6 is a large diameter tail tube, 7 is a tail plate, 8 is a pressure conduit, 9 is a cylinder type actuator, 10 is a control valve. It is.

The muffler main body 1 is cylindrical and has a front end plate 2 and a rear end plate 3 at front and rear end positions. Inside the muffler body 1, a resonance chamber and an expansion chamber (not shown) are defined. A mount rod 11 for supporting the muffler body 1 on the vehicle body is welded to the front end plate 2 and the rear end plate 3.

The end of the muffler inlet pipe 4 provided with a flange 4 a is connected to an exhaust tube from an engine to guide exhaust gas into the muffler body 1.

The small diameter tail tube 5 is connected to the rear end plate 3 of the muffler main body 1 and has a number of small holes 5a.

The large-diameter tail tube 6 is fixed to the base end of the small-diameter tail tube 5 via a support plate 12, and is coaxial with the small-diameter tail tube 5 at its outer peripheral position in a double tube structure. The donut-shaped space 15 that is provided and formed between the small-diameter tail tube 5 and the large-diameter tail tube 6 is used as an exhaust gas passage.

That is, only the small-diameter tail tube 5 is connected to the rear end plate 3 of the muffler main body 1, and the large-diameter tail tube 6 has a single tube structure fixed to the base end of the small-diameter tail tube 5.

The tail plate 7 is provided between the oblique opening end of the large diameter tail tube 6 and the opening end of the small diameter tail tube 5, and the tail plate 7 has a large number of small holes 7a. ing. The tail plate 7 serves as a support and fixing member for the large-diameter tail tube 6 like the support plate 12.

The control valve 10 is disposed at the opening of the distal end of the small-diameter tail tube 5 and continuously changes the valve opening according to the size of the piston stroke corresponding to the exhaust pressure level introduced from the pressure conduit 8. Opening / closing control is performed by a cylinder type actuator 9.

The pressure conduit 8 has a muffler inlet pipe 4 at one end.
The exhaust pressure of the muffler inlet pipe 4 is guided to the cylinder type actuator 9. The exhaust pressure may be led from the inside of the muffler main body 1 by the pressure conduit 8.

The cylinder type actuator 9 is fixed to a bracket 13 fixed to the large diameter tail tube 6. The actuator rod and the valve shaft are connected to a link mechanism 14 for converting a stroke operation of the actuator rod into a rotation operation of the valve shaft. Are connected by

Next, the operation will be described.

[Valve opening / closing action] The cylinder type actuator 9 employed in the present invention uses exhaust pressure as its driving source. Therefore, when the exhaust gas flows from the engine during traveling, the exhaust gas is guided to the cylinder chamber of the cylinder type actuator 9 via the pressure conduit 8, and the piston strokes in the cylinder chamber according to this pressure level. The valve opening of the control valve 10 connected to the rod of the mold actuator 9 is continuously changed according to the magnitude of the piston stroke.

Therefore, an experiment was conducted to confirm how the valve opening actually changes. As a result, the control valve 10 was fully closed until the engine speed reached 1500 rpm, and the engine speed was reduced. 1500-45
Up to 00 rpm, the opening of the control valve 10 increases as the engine speed increases, and the engine speed becomes 4500
When the rotation speed exceeds rpm, the control valve 10 has a characteristic of being kept fully open.

That is, instead of switching from fully closed to fully opened at a certain engine speed, 1500 to 4500
In the engine speed range of rpm, the valve exhibits characteristic characteristics in which the opening changes smoothly while maintaining the intermediate opening.
The opening / closing hunting of the valve due to the variation of the exhaust pressure in the intermediate opening range does not cause a problem because the width of the pressure dead zone due to the internal friction of the cylinder type actuator 9 does not cause a slow talk.

[Effect when Valve is Fully Closed] The flow of exhaust gas when the valve is fully closed is, as shown by the arrow in FIG. 4, the small-diameter tail tube 5 → the small hole 5a → the donut-shaped space 15 → the small hole 7a.
→ Atmosphere.

Therefore, when compared with a normal muffler having only a small-diameter tail tube having no small hole, the exhaust gas is discharged to the atmosphere through a curved path, so that a substantially long tail tube is set. The same goes,
The improvement of the resonance characteristics of the system is advantageous for reducing the muffled sound in the low frequency region.

That is, when compared with the discharge sound characteristic of the normal muffler shown in FIG. 6, the muffled sound in the low frequency region is reduced as indicated by the solid line characteristic A.

When the valve is fully opened, the flow of the exhaust gas when the valve is fully opened is, as shown by the arrow in FIG. 5, most of the exhaust gas is changed from the small-diameter tail tube 5 to the atmosphere. As in the case of the fully closed state, the order is small-diameter tail tube 5 → small hole 5a → doughnut-shaped space 15 → small hole 7a → atmosphere.

Therefore, when comparing the normal muffler with only the small-diameter tail tube having no small hole and the exhaust resistance, in addition to being directly discharged to the atmosphere directly through the small-diameter tail tube 5, the small-diameter tail tube 5 Is released to the atmosphere through the small hole 5a, the exhaust resistance is further reduced, and the engine output is improved.

That is, as compared with the output characteristics of the normal muffler shown in FIG. 7, as shown by the solid line characteristic B, the output characteristics are close to those of a sports muffler having a large tail tube, and the engine output increases.

Further, when compared with a normal muffler having only a small diameter tail tube having no small hole, the exhaust gas is discharged to the atmosphere through the donut-shaped space 15 so that the diameter of the tail tube can be substantially increased. By reducing the linear velocity of the exhaust gas and suppressing the turbulence of the flow of the exhaust gas by the small hole 7a of the large-diameter tail tube 7, as shown by the solid line characteristic A in FIG. Airflow noise is reduced.

[At the time of intermediate valve opening] In the intermediate valve opening region, the noise reduction performance gradually decreases as the valve opening increases, and conversely, the engine output performance increases as the valve opening increases. The shift is performed in a process in which the engine speed changes from 1500 rpm to 4500 rpm, so that the noise reduction performance is emphasized on the low engine speed side, and the engine output performance is emphasized on the high engine speed side. By making a smooth transition in accordance with the change in the rotation, a relationship is obtained in which the noise reduction performance and the improvement of the engine output are well balanced without a sense of incongruity.

Therefore, during the acceleration operation by depressing the accelerator, the control valve 10 is steplessly changed from the valve closing state to the valve opening degree by gradually increasing the valve opening degree from the valve closing state. Sound is obtained.

Next, the effects will be described.

(1) A small-diameter tail tube 5 connected to the rear end plate 3 of the muffler main body 1 and having a number of small holes 5a formed therein, and a support plate 12 provided on the base end of the small-diameter tail tube 5 Fixed through the small-diameter tail tube 5
A large diameter tail tube 6 installed in a coaxial double tube structure at the outer peripheral position thereof, and a pressure conduit 8 disposed at the tip opening position of the small diameter tail tube 5.
And a control valve 10 that is opened and closed by a cylinder-type actuator 9 that continuously changes the valve opening according to the size of the piston stroke according to the exhaust pressure level introduced from the engine. By using the tube, it is possible to provide an exhaust muffler with a control valve that has a large diameter tail tube that has the same silencing performance as a control type muffler using a dual tail, and also has the same excellent appearance and high output performance as a sports muffler.

(2) Only the small-diameter tail tube 5 is connected to the rear end plate 3 of the muffler main body 1, and the large-diameter tail tube 6 has a single tube structure fixed to the base end of the small-diameter tail tube 5. A tail plate 7 is provided at the open end of the tail tube 6 and the open end of the small-diameter tail tube 5, and a large number of small holes 7a are formed in the tail plate 7. The tail plate 7 can improve the appearance of the tail rear end portion while being easily diverted and applied.

(Embodiment 2) Embodiment 2 is an exhaust muffler with a control valve according to the first and third aspects.

In terms of structure, as shown in FIGS. 8 and 9,
The only difference is that the tail plate 7 is omitted in the configuration of the first embodiment. That is, this is an example in which only the small-diameter tail tube 5 is connected to the rear end plate 3 of the muffler main body 1, and the large-diameter tail tube 6 has a single-tube structure fixed to the base end of the small-diameter tail tube 5.

Next, the operation will be described.

FIG. 8 is a diagram for explaining the operation when the valve is fully closed.
FIG. 9 is a diagram for explaining the operation when the valve is fully opened.
7 is slightly inferior in noise reduction performance because the tail plate 7 is omitted, but the engine output performance is higher than the solid line characteristic B in FIG. 7 because the exhaust resistance is reduced by omitting the tail plate 7. .

Effectively, the following effect is added to the effect of (1) of the first embodiment.

(3) Only the small-diameter tail tube 5 is connected to the rear end plate 3 of the muffler main body 1 and the large-diameter tail tube 6 has a single tube structure fixed to the base end of the small-diameter tail tube 5. The muffler main body having a single tail tube can be easily applied to the muffler body as it is, and by omitting the tail plate 7, an engine output characteristic close to that of a sports muffler can be obtained in a high frequency region where the engine speed is high.

(Embodiment 3) Embodiment 3 is an exhaust muffler with a control valve according to the first and fourth aspects of the present invention.

As shown in FIGS. 10 and 11, the small-diameter tail tube 5 and the large-diameter tail tube 6 are structured as shown in FIGS.
Have a dual tube structure connected to the rear end plate 3 of the muffler main body 1, and a tail plate 7 is provided at an open end of the large-diameter tail tube 6 and an open end of the small-diameter tail tube 5. Many small holes 7a were opened. That is, in the first embodiment, the small-diameter tail tube 5 is used.
A single tube structure in which exhaust gas is emitted only from the muffler body 1 is a single tube structure in which exhaust gas is emitted from the muffler body 1 to a donut-shaped space 15 formed by installing the large-diameter tail tube 6. In that

Next, the operation will be described.

FIG. 10 is a diagram for explaining the operation when the valve is fully closed, and FIG. 11 is a diagram for explaining the operation when the valve is fully opened. In comparison with the first embodiment, when the valve is fully closed, one of the control valves is provided. 6 shows the same control performance as the conventional muffler having a dual tail tube, and when compared with a sports muffler having a large diameter tail tube, as shown by the solid line characteristic C in FIG. Sound reduction is achieved. However, when the output characteristic is compared with that of a sports muffler having a large diameter tail tube, the output is reduced as shown by the characteristic D in FIG.

When the valve is fully opened, the inside of the large-diameter tail tube 6 substantially serves as an exhaust gas passage.
As shown in the characteristic D, the engine output characteristic is almost the same as that of a sports muffler having a large-diameter tail tube, and the airflow noise in a high-frequency region is reduced as in the first embodiment.

Effectively, the following effect is added to the effect of (1) of the first embodiment.

(4) The small-diameter tail tube 5 and the large-diameter tail tube 6 have a dual tube structure in which both are connected to the rear end plate 3 of the muffler body 1.
A tail plate 7 is provided at the open end of the small diameter tail tube 5 and a large number of small holes 7a are formed in the tail plate 7, so that the muffler has the same noise reduction performance as a conventional muffler having a dual tail tube. The engine output performance substantially equal to that of the conventional sports muffler can be achieved, and the tail plate 7 can improve the appearance of the tail rear end.

Fourth Embodiment A fourth embodiment is an exhaust muffler with a control valve according to the first and fifth aspects.

As shown in FIGS. 12 and 13, the structure of the third embodiment differs from that of the third embodiment only in that the tail plate 7 is omitted. That is, the small-diameter tail tube 5
This is an example of a dual tube structure in which both the large diameter tail tube 6 and the large diameter tail tube 6 are connected to the rear end plate 3 of the muffler body 1.

Next, the operation will be described.

FIG. 12 is a diagram for explaining the operation when the valve is fully closed, and FIG. 13 is a diagram for explaining the operation when the valve is fully opened. In comparison with the third embodiment, the noise is reduced because the tail plate 7 is omitted. Although the performance is slightly inferior, the engine output performance is higher than the solid line characteristic D in FIG. 7 because the exhaust resistance is reduced by omitting the tail plate 7.

Effectively, the following effect is added to the effect of (1) of the first embodiment.

(5) Since the small-diameter tail tube 5 and the large-diameter tail tube 6 have a dual tube structure in which both are connected to the rear end plate 3 of the muffler main body 1, the muffler has the same noise reduction performance as a conventional muffler having a dual tail tube. Engine output performance equivalent to that of a conventional sports muffler can be achieved.

(Other Embodiments) In the embodiment, a butterfly valve is used as a control valve. However, a shutter valve or the like may be used as long as the valve opening can be changed steplessly. .

In the first embodiment, the example in which the exhaust pressure introducing end of the pressure conduit is used as the muffler inlet pipe has been described. However, the exhaust pressure introducing end of the pressure conduit is disposed in the muffler main body, upstream of the catalytic converter, or the like. It may be an example.

[0063]

According to the first aspect of the present invention, a small-diameter tail tube connected to the rear end plate of the muffler body and having a large number of small holes is coaxially disposed at an outer peripheral position of the small-diameter tail tube. And a large-diameter tail tube having a donut-shaped space formed between the small-diameter tail tube and the small-diameter tail tube is disposed at the front end opening of the small-diameter tail tube, and the exhaust gas is introduced from the pressure conduit. A control valve that is opened and closed by a cylinder-type actuator that changes the valve opening continuously according to the size of the piston stroke according to the atmospheric pressure level. Exhaust system with a control valve that achieves a large diameter tail tube that has the same high performance as the sports muffler while maintaining the performance It is possible to provide a La.

In addition, fine tuning (muffling performance, output performance) according to the user's needs is possible due to the degree of freedom in setting the installation form and dimensions of the small-diameter tail tube and the large-diameter tail tube constituting the double tube. An exhaust muffler with a control valve can be provided.

In the invention according to claim 2, claim 1
In the exhaust muffler with control valve described, only the small-diameter tail tube is connected to the rear end plate of the muffler body, and the large-diameter tail tube has a single-tube structure fixed to the base end of the small-diameter tail tube. A tail plate is provided at the opening end of the small-diameter tail tube and at the opening end of the small-diameter tail tube, and since a large number of small holes are formed in the tail plate, in addition to the above effects, the muffler body having the existing single tail tube is diverted as it is. And the tail plate can improve the appearance of the rear end of the tail.

According to the third aspect of the present invention, there is provided the first aspect.
In the exhaust muffler with a control valve described above, only the small diameter tail tube is connected to the rear end plate of the muffler body, and the large diameter tail tube has a single tube structure fixed to the base end of the small diameter tail tube. In addition to the effects of the invention described in 1, the existing muffler main body having a single tail tube can be easily applied without change, and the engine is close to a sports muffler in a high frequency region where the engine speed is high by omitting the tail plate. Output characteristics can be obtained.

In the invention according to claim 4, claim 1 is
In the exhaust muffler with a control valve described in the above, the small-diameter tail tube and the large-diameter tail tube have a dual tube structure in which both are connected to the rear end plate of the muffler body, and the open end of the large-diameter tail tube and the open end of the small-diameter tail tube. The tail plate is provided with a plurality of small holes, so that in addition to the effect of the invention described in claim 1, the noise reduction performance is equivalent to that of a conventional muffler having a dual tail tube, and a conventional sports muffler is provided. The engine output performance can be substantially the same as that of, and the appearance of the rear end of the tail can be improved by the tail plate.

In the invention according to claim 5, claim 1 is
In the exhaust muffler with a control valve described above, the small diameter tail tube and the large diameter tail tube both have a dual tube structure connected to the rear end plate of the muffler main body. It is possible to achieve both noise reduction performance equivalent to a muffler having a tail tube and engine output performance equivalent to a conventional sports muffler.

[Brief description of the drawings]

FIG. 1 is an overall perspective view showing an exhaust muffler with a control valve according to a first embodiment.

FIG. 2 is a rear view of the exhaust muffler with a control valve according to the first embodiment.

FIG. 3 is a sectional view showing a dual tail tube portion of the exhaust muffler with a control valve according to the first embodiment.

FIG. 4 is an operation explanatory view showing a flow of exhaust gas when the control valve of the exhaust muffler with the control valve according to the first embodiment is fully closed.

FIG. 5 is an operation explanatory diagram showing a flow of exhaust gas when the control valve of the exhaust muffler with a control valve according to the first embodiment is fully opened.

FIG. 6 is a characteristic diagram of a comparison between discharge noises of a conventional normal muffler and a sports muffler and an exhaust muffler with a control valve of the present invention.

FIG. 7 is an engine output comparison characteristic diagram of a conventional normal muffler and a sports muffler and an exhaust muffler with a control valve of the present invention.

FIG. 8 is an operation explanatory diagram showing a flow of exhaust gas when the control valve of the exhaust muffler with a control valve according to the second embodiment is fully closed.

FIG. 9 is an operation explanatory diagram showing a flow of exhaust gas when the control valve of the exhaust muffler with a control valve according to the second embodiment is fully opened.

FIG. 10 is an operation explanatory view showing the flow of exhaust gas when the control valve of the exhaust muffler with a control valve according to the third embodiment is fully closed.

FIG. 11 is an operation explanatory view showing the flow of exhaust gas when the control valve of the exhaust muffler with a control valve according to the third embodiment is fully opened.

FIG. 12 is an operation explanatory diagram showing a flow of exhaust gas when the control valve of the exhaust muffler with a control valve according to the fourth embodiment is fully closed.

FIG. 13 is an operation explanatory diagram showing a flow of exhaust gas when the control valve of the exhaust muffler with a control valve according to the fourth embodiment is fully opened.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Muffler main body 2 Front end plate 3 Rear end plate 4 Muffler inlet pipe 5 Small diameter tail tube 6 Large diameter tail tube 7 Tail plate 8 Pressure conduit 9 Cylinder type actuator 10 Control valve

Claims (5)

[Claims] 1. A small-diameter tail tube (5) connected to a rear end plate (3) of a muffler body (1) and having a plurality of small holes (5a) formed therein; A large-diameter tail tube (6) installed coaxially at an outer peripheral position and having a donut-shaped space (15) formed between the small-diameter tail tube (5) and the small-diameter tail tube (5); Opening / closing control by a cylinder type actuator (9) which is arranged at the tip opening position of 5) and continuously changes the valve opening according to the size of the piston stroke according to the exhaust pressure level introduced from the pressure conduit (8). An exhaust muffler with a control valve comprising: a control valve (10); 2. The exhaust muffler with a control valve according to claim 1, wherein only the small-diameter tail tube (5) is connected to a rear end plate (3) of the muffler body (1) and a large-diameter tail tube (6). Has a single-tube structure fixed to the base end of the small-diameter tail tube (5), and has a tail plate (7) at the open end of the large-diameter tail tube (6) and the open end of the small-diameter tail tube (5).
The tail plate (7) has a number of small holes (7).
An exhaust muffler with a control valve, wherein a) is opened. 3. The exhaust muffler with a control valve according to claim 1, wherein only the small-diameter tail tube (5) is connected to a rear end plate (3) of the muffler body (1) and a large-diameter tail tube (6). An exhaust muffler with a control valve characterized by having a single tube structure fixed to the base end of a small diameter tail tube (5). 4. The exhaust muffler with a control valve according to claim 1, wherein the small-diameter tail tube (5) and the large-diameter tail tube (6) are both connected to a rear end plate (3) of the muffler body (1). Tail plate (7) at the open end of the large diameter tail tube (6) and the open end of the small diameter tail tube (5)
The tail plate (7) has a number of small holes (7).
An exhaust muffler with a control valve, wherein a) is opened. 5. The exhaust muffler with a control valve according to claim 1, wherein both the small-diameter tail tube (5) and the large-diameter tail tube (6) are connected to a rear end plate (3) of the muffler body (1). Exhaust muffler with control valve characterized by dual tube structure.