KR101091952B1 - Muffler for Engine Waste Gas with Exterior Air Suction Means - Google Patents

Abstract

The present invention relates to a silencer for engine exhaust gas, and more particularly, by providing a suction means capable of sucking cold outside air, the noise caused by the flow of exhaust gas can be reduced, and the temperature of the exhaust gas is further lowered. A silencer for engine exhaust gas that can be made.

The present invention provides a silencer (1) for an engine exhaust gas comprising a silencer body (100) having a larger diameter than a suction pipe (200), a discharge pipe (400) and a suction pipe (200), the silencer (1). The engine provides a silencer for the engine exhaust gas, characterized in that it comprises a suction means 300 for sucking the outside air into the silencer body (100).

As another aspect of the present invention, the present invention is an engine exhaust gas silencer (1) comprising a silencer body 100 having a larger diameter than the suction pipe 200, the discharge pipe 400 and the suction pipe 200. In the method for reducing the noise, the method for reducing the noise is characterized in that it comprises a procedure for forming a suction means 300 in the silencer body 100 to suck the outside air into the silencer body 100 A noise reduction method of an engine silencer for exhaust gas is provided.

Marine, Silencer, Momentum, Loss, Noise, Reduction

Description

Muffler for Engine Waste Gas with Exterior Air Suction Means

The present invention relates to a silencer for engine exhaust gas, and more particularly, by providing a suction means capable of sucking cold outside air, the noise caused by the flow of exhaust gas can be reduced, and the temperature of the exhaust gas is further lowered. A silencer for engine exhaust gas that can be made.

Recently, as the operating conditions for industrial machinery are increased, the generation of noise from an engine including a high frequency component is rapidly increasing. These high-frequency noises are audible to the ear as a sharp and high sound due to the acoustic characteristics, which not only degrades the work efficiency of workers but may also cause hearing loss when left for a long time.

In particular, high-temperature, high-pressure exhaust gases emitted from engines, such as medium and large marine engines, when they are released into the atmosphere as a result of rapid expansion causes explosion sounds. At this time, the exhaust gas is very high temperature (300-500 degrees) and the speed is almost close to the speed of sound, so if it is released into the atmosphere without passing through the silencer, strong impact noise is generated. In order to prevent this, an expansion silencer that reflects combustion noise of an engine using a cross-sectional change of a pipe or a sound absorber that absorbs acoustic energy by placing a sound absorbing material inside the silencer is used.

There may be a number of silencers for engine exhaust gases, but it is necessary to minimize noise with minimal back pressure to ensure the engine's operating performance. Types of engine exhaust gas silencers that are frequently used include reflection silencers, interference silencers, interference and reflection complex silencers, absorption silencers, absorption and reflection compound silencers, and resonance silencers.

Reflective silencer is a structure in which several spaces are arranged in series, and each space partition is provided with a pipe, and the pulsating exhaust gas is cut off from the path, thereby reducing noise. In a reflected silencer, the noise attenuation is effected by the impact reflection of the cross section of the partition and pipe. An interfering silencer is a collection of exhaust pipes that are branched into several pieces and then gathered together to convert the shock noise of the exhaust gases into weak sound waves. Interference-reflective compound silencers are connected to several different sound pipes and partitioned spaces. In addition to attenuating the noise, the reflex action also attenuates sound vibrations that are additionally unpleasant.

Absorption silencers have the advantage of low flow resistance and are used in exhaust systems where the flow resistance must be small. Exhaust gas, which is shockingly introduced into the silencer, enters the compartment filled with sound absorbing material through a hole drilled in the sound pipe by vibration. Exhaust gas exhausts the silencer in a state where the vibration energy is exhausted by the friction with the sound absorbing material and there is no impact. Absorption-reflection compound silencers improve the noise attenuation effect of absorption silencers in the specific vibration region by the reflection principle.

The resonant silencer mainly consists of a diverged resonator. Especially when the noise level is high, it can reduce the flow resistance of the exhaust gas without any problem.

1, the expansion type silencer 1 is briefly shown as a conventional silencer for engine exhaust gas. The expansion silencer is designed to reduce transmitted sound waves by partially reflecting toward the inlet 20 as the acoustic impedance rapidly increases as the exhaust gas 50 enters the expansion body 10. The exhaust gas 50 having the reduced acoustic energy exits toward the outlet 40. If necessary, a resonator 30 including a plurality of noise suction holes 31 is installed at the inlet 20 side or the outlet 40 side. Noise may be further reduced.

However, the silencer 1 for the engine exhaust gas has limitations in order to sufficiently reduce the high-temperature, high-pressure exhaust gas 50 impact sound of a large engine despite various advantages. Because the exhaust gas 50 speed of the engine is faster than about 40 ~ 50m / s and the pressure is discharged as high as 3 ~ 5bar, exhaust gas 50 discharged from the inlet pipe 20 to the muffler 1 is This is because acoustic energy is not sufficiently attenuated and exits the silencer 1 by forming a jet core 51. In addition, since the temperature of the exhaust gas 50 is not sufficiently lowered, the welder 1 of the silencer 1 may be melted by the exhaust gas 50 having a high temperature (300 to 500 degrees).

The present invention is to solve the above problems, it is possible to reliably reduce the noise of the flowr even in the exhaust gas of a large engine with a high speed, and additionally reliable engine exhaust gas silencer that can sufficiently lower the temperature It is to provide.

In order to achieve the above object, the present invention provides a silencer (1) for an engine exhaust gas including a silencer body (100) having a diameter larger than that of the suction pipe (200), the discharge pipe (400), and the suction pipe (200). In the silencer (1) provides a silencer for the engine exhaust gas, characterized in that it comprises a suction means 300 that can suck the outside air into the silencer body (100).

In addition, the suction means 300 is provided in the silencer body 100 to provide a silencer for engine exhaust gas, characterized in that one or more suction holes 310 are included.

Here, the suction hole 310 is preferably formed on the side wall of the suction pipe 200 of the silencer body 100.

In addition, the suction means 300 includes a bypass tube 320 for bypassing a part of the exhaust gas 520 passing through the suction pipe 200; And an actuator 305 formed around the suction hole 310 to selectively introduce external air from the suction hole 310 and the exhaust gas 520 from the bypass pipe 320 into the silencer body 100. ) Is preferably further included.

Here, the length of the bypass tube 320 may be determined in relation to the flow noise wavelength of the exhaust gas 520.

In addition, the bypass tube 320 may be spiral.

On the other hand, the length (L2) of the bypass pipe 320 is the flow noise of the exhaust gas 520 to the length (L1) of the suction pipe 200 to the silencer body 100 from the diverging portion of the bypass pipe 320 It is preferable to determine by adding half of the wavelength?.

In addition, the suction means 300 further includes a small silencer 600, so that the noise of the silencer body 100 is prevented from leaking to the outside through the suction means 300. to provide.

Here, the small silencer 600 is preferably an absorption type silencer including a sound absorbing material.

As another aspect of the present invention, the present invention is an engine exhaust gas silencer (1) comprising a silencer body 100 having a larger diameter than the suction pipe 200, the discharge pipe 400 and the suction pipe 200. In the method for reducing the noise, the method for reducing the noise is characterized in that it comprises a procedure for forming a suction means 300 in the silencer body 100 to suck the outside air into the silencer body 100 A noise reduction method of an engine silencer for exhaust gas is provided.

Engine exhaust gas silencer provided with an external air suction means provided in the present invention is applied to large engines can surely reduce the noise caused by the flow, and also has the effect of reducing the temperature of the exhaust gas without a special device . In particular, there is an advantage that the flow noise can be sufficiently reduced by bypassing a part of the exhaust gas, if necessary, by the selection mechanism of the suction means to suck the exhaust gas into the silencer body.

Specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. Figure 3 is a perspective view of the engine exhaust gas silencer with a suction hole of the present invention, Figure 4 is a side cross-sectional view of the silencer for engine exhaust gas of the present invention, Figure 5 is an engine exhaust gas with a suction hole of the present invention This graph shows the noise reduction performance of the silencer. 6 is a perspective view of an exhaust gas silencer showing a second embodiment of the present invention, FIG. 7 is a perspective view of an exhaust gas silencer showing a third embodiment of the present invention, and FIG. 8 is a fourth embodiment of the present invention. The perspective view of the silencer for exhaust gas shown is shown. Matters that are not required to understand the technical spirit of the invention as parts that are not different from the prior art are excluded from the description, but the technical spirit and protection scope of the present invention are not limited thereto.

First, the first embodiment of the silencer for engine exhaust gas provided with the external air suction means of the present invention will be described in detail with reference to FIGS. 3 and 4.

Engine exhaust gas silencer (1) of the present invention comprises a suction pipe (200); A silencer body 100 which is connected to the suction pipe 200 with a diameter larger than that of the suction pipe 200; In the silencer 1 for a conventional engine exhaust gas comprising a discharge pipe 400 subsequent to this, the suction hole for sucking the outside air to a portion of the silencer body 100 on the side to which the suction pipe 200 is bonded. 310 is formed so that relatively cool air outside the silencer 1 is introduced into the silencer body 100.

3 and 4 illustrate a silencer in which a plurality of suction holes 310 are formed as the suction means 300 on the side of the silencer body 100. Although the drawing shows that eight suction holes 310 are formed, the present invention is not limited thereto, and the suction holes 310 may be added or deleted within the limit that noise from the silencer body 100 is not excessively leaked. In addition, although the drawing shows that the suction hole 310 is formed on the side wall of the muffler body 100, it enters the flow noise region 500 formed by the jet core 510 of the exhaust gas 520 to be described later. The suction hole 310 may be formed along the circumference of the silencer body 100 within the range (the area indicated by L in FIG. 4) as long as it does not go. The size of the suction hole 310 can be smoothly introduced in the outside air is excessively large may be appropriately determined in such a way that the noise inside the silencer body 100 does not leak.

With reference to Figure 4 will be described in more detail the operation and effect of the silencer (1) for the engine exhaust gas having an external air suction means of the present invention.

Exhaust gas 520 discharged from the large engine enters the silencer body 100 along the suction pipe 200 of the silencer 1 directly connected to the engine. At this time, the exhaust gas 520 is at least 300 to 500 degrees high temperature, the speed is 40 to 50 m / s or even close to the speed of sound. The high velocity exhaust gas 520 exits the intake pipe 200 in jet form and is considerably larger in diameter than the intake pipe 200 (usually the silencer body 100 has a diameter of at least 1 m) to the silencer body 100. As it is discharged, the jet core 510 is formed, and around the jet core 510, a boundary with air in the silencer body 100 is formed to form a flow noise region 500 classified as turbulent. It is no exaggeration to say that noise due to flow is generated in the flow noise region 500 shown substantially. As the flow noise region 500 spreads wider at a larger angle, the noise due to flow becomes larger.

In the first embodiment of the present invention, the suction hole 310 is formed on the inlet side of the silencer body 100 as the suction means 300 which can suck the outside air, and thus the outside of the temperature lower than the exhaust gas 520. Air enters through the suction hole 310. Basically, a low pressure region is generated by the jet core 510 inside the silencer body 100, and thus a jet induced flow may be generated.

The external cold air 340 introduced through the suction hole 310 serves to lose momentum of the exhaust gas 520 of the jet core 510. That is, since energy is required to attract the outside air 340, the momentum of the exhaust gas 520 is lost, thereby decreasing the flow energy. This in turn serves to reduce the angle of occurrence of the flow noise area 500 has the effect of reducing the noise resulting from the flow.

The external cool air introduced through the suction hole 310 meets the exhaust gas 520 to lower the temperature of the exhaust gas 520. Exhaust gas 520 of a large engine usually has a problem of melting the welded portion of the muffler 1 and thus impairing durability because the temperature is about 300 to 500 degrees, but by employing suction means for sucking the outside air of the present invention. Since the temperature can be reduced, the side effect of improving the durability of the silencer 1 can also be obtained.

Figure 5 is a graph showing the noise reduction performance of the silencer for engine exhaust gas of the present invention. As can be seen in the figure, when the flow energy is calcined by the momentum loss of the exhaust gas 520, it can be seen that the noise reduction performance is greatly improved in the 500 to 1500 Hz band.

Next, a second embodiment of the silencer for engine exhaust gas of the present invention will be described in detail with reference to FIG. 6.

Unlike the first embodiment, the second embodiment of the present invention, as the suction means 300, in addition to the suction hole 310, the exhaust pipe 520 and the actuator (200) bypassing the suction pipe 200. 305) is further included. The actuator 305 is paired with the suction hole 310 and the bypass tube 320 to constitute one suction means 300. Although only one suction means 300 is shown in the drawing, it is natural that it may be further included as needed.

The bypass pipe 320 is a pipe connecting the suction pipe 200 and the actuator 305 to bypass the part of the exhaust gas 520 passing through the suction pipe 200 to reach the actuator 305. The actuator 305 serves to select the outside air 340 coming from the suction hole 310 and the exhaust gas 520 coming through the bypass pipe 320 and inject it into the silencer body 100. The actuator 305 may be automatically controlled electronically and may be manually operated as necessary. That is, only the cool outside air 340 that enters through the suction hole 310 without the exhaust gas 520 by the operation of the actuator 305 may enter the silencer body 100 as a whole. Only the exhaust gas 520 may be separately entered along the bypass pipe 320 into the silencer body 100 without the air 340. If necessary, the outside air 340 and the exhaust gas 520 coming along the bypass pipe 320 may be mixed at an appropriate ratio and introduced into the body 100 according to a selection by those skilled in the art.

Through the second embodiment of the present invention, noise due to flow that may leak to the outside along the suction hole 310 is prevented. That is, when the suction hole 310 is formed in the silencer body 100, the noise inside the body 100 may escape to the outside, and thus the function of the silencer 1 may be degraded. Alternatively, the suction hole 310 may be replaced with the exhaust gas 520. By introducing into (100), the same disadvantages can be compensated for while achieving a flow energy reduction effect. In addition, if the bypass pipe 320 is placed separately from the suction pipe 200, the same exhaust gas 520 is introduced into the body 100 while undergoing different flow paths between the suction pipe 200 and the bypass pipe 320. The effect of being further reduced is obtained. That is, since the bypass pipe 320 is formed longer than the suction pipe 200 to serve as an expandable silencer, sound waves are canceled with each other to further reduce noise.

Next, a third embodiment of the silencer for engine exhaust gas of the present invention will be described with reference to FIG.

The third embodiment of the present invention is the same as the second embodiment except that the bypass tube 320 is elongated in a spiral shape as shown in FIG. 7. The spiral length of the bypass tube 320 is determined in relation to the wavelength of the exhaust gas 520. For example, the wavelength of the exhaust gas 520 is estimated to be λ, the length of the suction pipe 200 from the point where the bypass pipe 320 branches to the silencer body 100 is L1, and the bypass pipe 320 In the case of the length L2, if the length of L2 is determined so that (L2-L1) is λ / 2, the expansion silencer is configured by the bypass pipe 320 to obtain the effect of minimizing the flow noise of the exhaust gas 520. . Although one bypass tube 320 and suction means 300 are illustrated in FIG. 7, a plurality of bypass tubes 320 and suction means 300 may be provided in various forms as necessary.

Next, a fourth embodiment of the silencer for engine exhaust gas of the present invention will be described in detail with reference to FIG. 8.

The fourth embodiment of the present invention is characterized in that the small silencer 600 is added to the suction means 300. In the case where the silencer body 100 includes the suction hole 310, when the size of the suction hole 310 is excessive, leakage of flow noise may occur from the inside of the body 100, so that the silencer 600 may be prevented. ) Is connected to the suction hole (310). Here, the small silencer 600 may prevent the noise 630 from escaping, but may use an absorbing silencer such that the flow resistance does not occur in the external air 340 introduced from the outside. Absorption-type small silencer 600 is provided with a perforated tube 620 in a hole inside the case and includes a sound absorbing material 610 between the case and the perforated tube 620, so it will be described in detail in the art. Is omitted.

According to the fourth embodiment of the present invention, even when some noise is leaked to the suction hole 310 for introducing outside air, the small noise silencer 600 is attached to prevent leakage of the air without disturbing the inflow of outside air. The sensory evaluation of noise is improved.

Engine exhaust gas silencer provided with an external air suction means according to the present invention can be said that the industrial applicability is sufficient because it is mounted on a large engine can significantly improve the noise without hindering the performance of the engine.

1 is a perspective view of a conventional silencer for engine exhaust gas

Figure 2 is a side cross-sectional view of a conventional silencer for engine exhaust gas

Figure 3 is a perspective view of the silencer for engine exhaust gas provided with a suction hole of the present invention

Figure 4 is a side sectional view of the silencer for the engine exhaust gas of the present invention.

5 is a graph showing the noise reduction performance of the silencer for engine exhaust gas provided with the suction hole of the present invention.

6 is a perspective view of a silencer for exhaust gas showing the second embodiment of the present invention.

7 is a perspective view of a silencer for exhaust gas showing the third embodiment of the present invention.

8 is a perspective view of a silencer for exhaust gas showing the fourth embodiment of the present invention.

DESCRIPTION OF REFERENCE NUMERALS

100: silencer body 200: suction pipe

300: suction means 305: actuator

310: suction hole 320: bypass tube

330: shielding member 400: discharge piping

510: jet core 600: small silencer

610: sound absorbing material

Claims (10)

In the engine exhaust gas silencer (1) comprising a suction pipe 200, a discharge pipe 400 and a silencer body 100 having a larger diameter than the suction pipe 200, the silencer (1) is the outside air It comprises a suction means 300 that can suck the silencer body 100, The suction means 300 is formed in the silencer body 100, the at least one suction hole 310, bypass pipe 320 for bypassing a part of the exhaust gas 520 passing through the suction pipe 200, And an actuator 305 formed around the suction hole 310 to selectively introduce external air from the suction hole 310 and the exhaust gas 520 from the bypass pipe 320 into the silencer body 100. More, The length of the bypass tube 320 is determined in relation to the flow noise wavelength of the exhaust gas 520, and the length L2 of the bypass tube 320 is from the portion where the bypass tube 320 diverges from the silencer body 100. Silencer for engine exhaust gas, characterized in that determined by adding half of the flow noise wavelength (λ) of the exhaust gas 520 to the length (L1) of the suction pipe 200 to delete The silencer for engine exhaust gas according to claim 1, wherein the suction hole 310 is formed on the side wall of the suction pipe 200 of the silencer body 100. delete delete The silencer for engine exhaust gas according to claim 1, wherein the bypass tube 320 is spiral. delete According to any one of claims 1, 3, 6, The suction means 300 further comprises a small silencer 600, the noise of the silencer body 100 through the suction means 300 Silencer for engine exhaust gas, characterized by prevention of leakage 9. The silencer for engine exhaust gas according to claim 8, wherein the small silencer 600 is an absorption type silencer including a sound absorbing material. delete

Images