KR20030008064A - Low noise tuning muffler - Google Patents

Abstract

PURPOSE: A low noise tuning muffler is provided to reduce noise by guiding the flow of noise into a predetermined passage in the muffler. CONSTITUTION: A casing(32) is fixed on the end of an exhaust pipe(24), and has an exhaust port(44) for exhausting exhaust gas. A porous pipe(34) installed at the inside of the casing has a plurality of hole, and connects the exhaust pipe to exhaust port. The casing is filled with a sound absorbing material(18) covering the porous pipe. An exhaust gas guide pipe(36) for flowing exhaust gas and noise is fixed on the exhaust port, and is extended into the inside of the porous pipe.

Description

Low noise tuning muffler

The present invention relates to a tuning muffler, and more particularly, to a low noise tuning muffler configured to generate only a noise of a normal bulkhead type muffler by inducing a flow of noise generated from an engine to a predetermined path in a muffler.

Mufflers are devices designed to reduce noise from internal combustion engines, usually in the form of a cylindrical cylinder. There are various ways of canceling the noise of the muffler according to the principle, and can be roughly classified into inflatable, resonance, absorption, and partition walls. Among the four methods, the bulkhead type is mainly used.

In addition, as known in the art, increasing the noise effect of the muffler increases the resistance to the flow of the exhaust gas, that is, the back pressure, thereby lowering the output of the engine. Conversely, lowering the noise effect lowers the resistance to the flow of exhaust gas, which increases the engine's output, but instead increases the noise. Race cars, for example, are equipped with a muffler with very low back pressure, which increases the engine's output, but is very loud.

Recently, various tuning products have become popular among car enthusiasts. Among them, the tuning muffler is popular with young people because it enhances the engine's output and externally emits a larger exhaust sound than ordinary bulkhead mufflers.

1 is a cross-sectional view showing a conventional tuning muffler.

As shown, the conventional tuning muffler 10 is fixed to the end of the exhaust pipe 24 connected to the engine, the end is provided with a casing 12 having a diffuser 20, the inside of the casing 12 It comprises a perforated pipe (14) connecting the exhaust pipe (24) and the diffuser (20) and providing an exhaust passage (22), and a sound absorbing material (18) filled in the casing (12) and surrounding the perforated pipe (14). do.

The perforated pipe 14 is a pipe in which a plurality of holes 16 are formed on the circumferential surface, and among the noise generated by the engine, in particular, high frequency is moved to the sound absorbing material 18 through the hole 16 to be absorbed or attenuated by the sound absorbing material. Be sure to On the other hand, the perforated pipe 14 can be seen that the internal exhaust passage 22 is completely open in order to prevent the back pressure (시) is generated when the exhaust gas discharged from the engine.

However, since the conventional tuning muffler 10 configured as described above has no obstacle that prevents the exhaust gas from being exhausted in the exhaust passage 22, the exhaust gas is discharged as it is along the direction of arrow a, and the output of the engine is good. In addition to the exhaust gas, the noise of the engine is emitted without any obstacle, so the noise is too large, there is a problem that various damages caused by the noise occurs.

The present invention has been made to solve the above problems, by installing an exhaust gas induction pipe inside the exhaust gas induction pipe to guide the flow of exhaust gas and noise generated from the engine to a predetermined path, active noise control (active The purpose of the present invention is to provide a low noise tuning muffler that is configured to generate noise equivalent to that of a general bulkhead muffler and to output a level of a general high noise high output tuning muffler.

1 is a cross-sectional view showing a conventional tuning muffler.

Figure 2 is a cross-sectional view showing a low noise tuning muffler according to an embodiment of the present invention.

Figure 3 is a perspective view showing a porous pipe applied to a low noise tuning muffler according to an embodiment of the present invention.

Figure 4 is a perspective view showing the exhaust gas induction pipe applied to the low noise tuning muffler according to an embodiment of the present invention.

5 is a view partially illustrating the flow of exhaust gas and noise in the low noise tuning muffler according to an embodiment of the present invention.

6 is a view showing the noise reduction effect by the active noise control (active noise control).

<Explanation of symbols for the main parts of the drawings>

10: tuning muffler 12, 32: casing

14, 34: hole pipe 16, 40: hole

18: sound absorbing material 20, 38: diffuser (diffuser)

22: exhaust passage 24: exhaust pipe

30: low noise tuning muffler 36: exhaust gas induction pipe

42: expansion part 44: exhaust vent

In order to achieve the above object, the present invention is fixed to the end of the vehicle exhaust pipe to provide an inner space and the casing is formed with an exhaust port through which exhaust gas escapes on one side; A perforated pipe installed in the casing to connect the exhaust pipe and the exhaust port, and having a plurality of holes formed in the circumferential surface thereof; A sound absorbing material filled in the casing and surrounding the perforated pipe; A pipe through which exhaust gas flows inside, and its outer circumferential surface is tightly fixed to the exhaust port, and one end thereof extends a predetermined length to the inside of the perforated pipe. And an exhaust gas induction pipe allowing noise to flow.

In addition, the end of one end of the exhaust gas induction pipe is extended in the radial direction to form an expansion portion, the other end is characterized in that it extends to the outside of the casing through the exhaust port to form an extended diffuser.

In addition, the inner diameter of the exhaust gas induction pipe is 70% to 80% of the inner diameter of the perforated pipe, the insertion depth of the exhaust gas induction pipe to the perforated pipe is characterized in that 1/4 to 1/2 of the length of the perforated pipe.

In addition, the diameter of the hole facing the outer peripheral surface of the exhaust gas induction pipe in the hole of the perforated pipe is characterized in that 1.5 to 2.5 times larger than the diameter of the hole formed in the other portion.

In addition, the expansion portion is bent in the shape of a trumpet to guide the exhaust gas flowing through the perforated pipe to the inside of the exhaust gas induction pipe and the outside surface flows between the gap between the exhaust gas induction pipe and the perforated pipe. It is characterized by guiding the exhaust gas to the sound absorbing material and the exhaust passage.

Hereinafter, one embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

Basically, the low-noise tuning muffler of the present invention induces sound waves (hereinafter, referred to as noise) of the explosive sound passing through the muffler to a predetermined path so as not to interfere with the discharge of the douche, so that the sound waves collide with each other. It is based on the principle of attenuating noise by the same known active noise cotrolling principle.

2 is a cross-sectional view showing a low noise tuning muffler according to an embodiment of the present invention.

Referring to the drawings, the low noise tuning muffler 30 according to the present embodiment is fixedly connected to the exhaust pipe 24 of the vehicle, provides an inner space, and has a casing having an exhaust port 44 on the opposite side of the exhaust pipe 24 ( 32 and a perforated pipe 34 fixed to the inside of the casing 32 to connect the exhaust pipe 24 and the exhaust port 44 to provide the exhaust passage 22, and to the inner circumferential surface of the exhaust port 44. It is fixed and is configured to include an exhaust gas induction pipe 36, one end of which is inserted into the perforated pipe (34).

In addition, the casing 32 is filled with a sound absorbing material 18 surrounding the perforated pipe 34. The sound absorbing material 18 absorbs high frequency, especially among sound waves of noise generated from an engine, and may be, for example, steel wool.

The perforated pipe 34 is a pipe having a constant diameter in which a plurality of holes (16 and 40 in Fig. 3) are formed through the circumferential surface as shown in Fig. 3. The perforated pipe 34 allows the sound wave of the noise to pass through the holes 16 and 40 like the conventional perforated pipe (14 in FIG. 1) to move toward the sound absorbing material 18 side.

On the other hand, the holes 16 and 40 formed in the perforated pipe 34 have different diameters. That is, in the perforated pipe 34, the hole 40 in the portion facing the outer circumferential surface of the exhaust gas induction pipe 36 is formed larger than the diameter of the hole 16 in the other portion. This is intended to more easily move the noise introduced to the sound absorbing material 18 side between the gap between the perforated pipe 34 and the exhaust gas induction pipe 36, as will be described later.

The exhaust gas induction pipe 36 is a pipe whose both ends are expanded as shown in FIG. This is a passage for discharging the noise and exhaust gas which has been moved into the casing 32 through the exhaust pipe 24 to the outside of the casing 32.

In addition, the outer circumferential surface of the exhaust gas induction pipe 36 guides some of the exhaust gas and noise flowing between the exhaust gas induction pipe 36 and the perforated pipe 34 to move in the direction of arrow k, for example. It will cause extinction interference by causing it to collide with the exhaust gases and noise.

That is, the sound waves of the noises are mutually extinguished by colliding the noises directed toward the arrow k direction and the noises directed to the arrow b direction through the exhaust passage 22 so that the noise is reduced.

This is a known active noise control principle of reducing the size of sound waves that noise has as it impinges the noise on the noise as shown in FIG.

The exhaust gas induction pipe 36 is fixed to the inner circumferential surface of the exhaust port 44 in close contact with the outer circumferential surface so that exhaust gas and noise do not leak out therebetween. In addition, one end of the end inserted into the perforated pipe 34 is extended to the outside like a trumpet to form an expansion part 42, and the other end is extended in a straight line to form a known diffuser 38.

The expansion pipe 42 is a place where the exhaust gas introduced to the sound absorbing material side is returned along the arrow b direction of FIG. 2, and exhausts the exhaust gas flowing into the interspace 46 from the internal exhaust passage 22 and returns. It is a part formed so that gas flow is not disturbed.

On the other hand, the diameter (d1) of the exhaust gas induction pipe 36 is to be 70% to 80% of the diameter (d2) of the perforated pipe 34, the exhaust gas induction pipe 36 of the perforated pipe 34 The insertion depth p may be 1/4 to 1/2 of the length of the perforated pipe 34.

In addition, the gap formed between the distal end of the expansion pipe 42 and the inner circumferential surface of the perforated pipe 34 is an outlet through which the exhaust gas and the noise entering the sound absorbing material pass through the space between the exhaust gas induction pipe 36 and the perforated pipe 34. , Gap clearance (g of FIG. 5) depends on the size of the muffler and the displacement of the engine.

Usually, the clearance gap is about 5% to 7% of the diameter of the perforated pipe 34. For example, when the diameter of the perforated pipe 34 is 100 mm, the clearance gap is 5 mm to 7 mm.

As the clearance gap g is wider, the damping effect of the noise is higher, but the back pressure applied to the exhaust gas is slightly higher. On the contrary, the narrower the gap, the more the engine output increases, but the noise increases.

3 is a perspective view illustrating a porous pipe applied to a low noise tuning muffler according to an embodiment of the present invention.

As shown, the perforated pipe 34 is a hollow cylinder, and a plurality of holes 16 and 40 are formed through the circumferential surface thereof. Further, in the holes 16 and 40, the diameter of the other hole 40 is relatively larger than that of the one hole 16. The relatively large hole 40 of the holes 16 and 40 is formed to be 1.5 to 2.5 times larger than the diameter of the small hole 16.

4 is a cutaway perspective view illustrating an exhaust gas induction pipe applied to a low noise tuning muffler according to an embodiment of the present invention.

As shown in the drawing, the expansion pipe 42 formed at one end of the exhaust gas induction pipe 36 is curved in a streamline shape and extends outward. Accordingly, the inner surface of the expansion pipe 42 naturally introduces noise and exhaust gas into the exhaust gas induction pipe 36 and at the same time the space 46 between the exhaust gas induction pipe 36 and the perforated pipe 34. Can be prevented from entering, and can be led to the sound absorbing material 18 and the exhaust passage 22 on the outer surface.

The diffuser 38, like the known diffuser, diffuses the exhaust gas and noise to lower the noise.

FIG. 5 is a view partially illustrating the flow of exhaust gas and noise in the low noise tuning muffler according to an embodiment of the present invention.

The same reference numerals as the above reference numerals denote the same members having the same function.

Referring to the drawings, the exhaust gas and noise emitted from the engine flows through the exhaust passage 22 of the perforated pipe 34, and part of the exhaust gas is introduced to the outside of the casing 32 through the exhaust gas induction pipe 36. It flows to the sound absorbing material 18 side through the holes 16 and 40 of the perforated pipe 34.

The exhaust gas and noise flowing toward the sound absorbing material 18 move to the interspace 46 and are turbulent in the interior of the interspace 46, and some move back to the sound absorbing material 18 through the hole 40, or the It also flows back in the opposite direction from the interspace and collides with the exhaust gas and noise which are continuously discharged as shown in FIG. 2.

As a result, the noise passes through the sound absorbing material 18 to be extinguished, or is canceled by the extinction interference caused by the collision.

FIG. 6 is a view schematically showing a noise reduction effect by active noise control. Basically, the sound waves of the noise emitted from the engine have various waveforms ranging from low frequency to high frequency, but only one waveform is shown in this drawing for conceptual explanation.

As shown, it can be seen that the acoustic noise s1 of the exhaust noise and the induced noise s2 returned by being induced in the reverse direction by the exhaust gas induction pipe 36 cause mutual extinction interference. The sound waves of the noise finally discharged to the outside by the extinction interference, such as the sound wave s3 of the attenuated noise, the amplitude is small, the noise is reduced.

On the other hand, the degree of attenuation of the noise through the extinction interference can be adjusted by varying the diameter or insertion depth of the exhaust gas induction pipe 36 with respect to the perforated pipe (34). This means that the minimum noise can be obtained by experimentally adjusting the diameter or the insertion depth in various ways.

In the following table, the inner diameter of the perforated pipe 34 is 73 mm, the inner diameter of the exhaust gas induction pipe 36 is 56 mm, and the gap between the tip of the expansion pipe 42 and the inner circumferential surface of the perforated pipe 34 is 4 mm. 16,40) diameters are 2.5mm and 5mm, respectively, to produce a muffler, which is the actual test result.The low-noise tuning muffler manufactured as described above is measured and mounted on Tiburon of Hyundai Motor, but Tiburon is installed at the factory. It is the result of measuring the noise value of the state which attached the general partition type muffler, and the noise value of the state which removed the said partition wall type muffler and installed the low noise tuning muffler of this invention in place.

RPM Factory-mounted bulkhead muffler (dB) Low noise tuning muffler of this invention (dB) Idling 65 67 2000 71 72 3000 75 75 4000 85 81 6000 95 98

As shown in the above experimental values, when the low noise tuning muffler of the present invention is mounted, the noise is almost similar to that of the general partition type muffler, and the noise of the low noise tuning muffler of the present invention is smaller at 4000 RPM. Able to know.

In addition, in the case of the conventional general tuning muffler, in consideration of the fact that the noise of about 100dB is usually about 3000RPM to 4000RPM as in the known fact, the low noise tuning muffler of the present invention has the same power as the normal tuning muffler, and the noise is the same as that of the general bulkhead muffler. You can see that it provides the same performance.

As mentioned above, although this invention was demonstrated in detail through the specific Example, this invention is not limited to the said Example, A various deformation | transformation is possible for a person with ordinary knowledge within the scope of the technical idea of this invention.

The low-noise tuning muffler of the present invention made as described above is provided with an exhaust gas induction pipe therein so that the exhaust gas induction pipe induces a flow of exhaust gas and noise generated from an engine to a predetermined path and continues to be discharged. By canceling the noise through noise and interference, it generates only the same level of noise as that of a general bulkhead muffler, and also outputs the level of a general high noise high power tuning muffler.

Claims (5)

A casing 32 fixed to an end of the vehicle exhaust pipe 24 and providing an internal space, and having an exhaust port 44 through which exhaust gas is discharged; A perforated pipe (34) installed in the casing (32) to connect the exhaust pipe (24) and the exhaust port (44) and having a plurality of holes (16, 40) formed therethrough on a circumferential surface thereof; A sound absorbing material 18 filled in the casing 32 and surrounding the perforated pipe 34; Exhaust gas flows inside the outer peripheral surface is tightly fixed to the exhaust port 44, one end is extended a predetermined length to the inside of the perforated pipe 34, the outer peripheral surface is spaced apart from the inner peripheral surface of the perforated pipe 34 This comprises an exhaust gas induction pipe (36) for allowing exhaust gas and noise to flow even in the gap. The method of claim 1, An end of one end of the exhaust gas induction pipe 36 is extended in a radial direction to form an expansion pipe 42, and the other end extends outside the casing 32 through an exhaust port 44 and expands the diffuser 38. Low noise tuning muffler, characterized in that. The method of claim 1, The inner diameter of the exhaust gas induction pipe 36 is 70% to 80% of the inner diameter of the perforated pipe 34, and the insertion depth of the exhaust gas induction pipe 36 with respect to the perforated pipe 34 is the length of the perforated pipe 34. Low noise tuning muffler, characterized in that 1/4 to 1/2. The method of claim 3, wherein Among the holes 16 and 40 of the perforated pipe 34, the diameter of the hole 40 facing the outer circumferential surface of the exhaust gas induction pipe 36 is 1.5 to 2.5 times larger than the diameter of the hole 16 formed in another portion. Low noise tuning muffler characterized by. The method of claim 2, The expansion pipe 42 is curved in a trumpet shape to guide the exhaust gas flowing through the perforated pipe 34 to the inside of the exhaust gas induction pipe 36 and to the outside surface of the exhaust gas induction pipe ( A low noise tuning muffler, characterized by guiding the exhaust gas flowing between the gap between the 36 and the perforated pipe 34 toward the sound absorbing material 18 and the exhaust passage 22.