Muffler and vehicle comprising same

Abstract

The present invention provides a muffler for a vehicle exhaust system of a fuel cell system capable of reducing high-frequency noise and reducing noise generated from a drain port, the muffler comprising: a housing having an inlet and an outlet; the perforated pipe is positioned in the shell and is provided with a plurality of through holes; the at least one baffle plate is configured between the shell and the perforated pipe so as to divide an internal space between the shell and the perforated pipe into a plurality of resonance chambers; and a cover mounted in the housing to support the perforated tube and to demarcate a most downstream resonance chamber.

Description

Technical Field

[0001] The present invention relates to a muffler for a vehicle. Background Art

[0002] A fuel cell vehicle using a fuel cell system is provided with an exhaust system that exhausts exhaust gas from the fuel cell. The exhaust system is configured to exhaust moisture, unreacted hydrogen, and unreacted air generated during a power generation reaction in a fuel cell stack.

[0003] In the exhaust system, high-frequency noise may be generated, such as the noise of high-speed airflow, so a muffler may be installed to reduce the noise. A sound absorbing material formed of glass wool, high-density polyethylene (HDPE), etc. is formed inside the muffler to reduce the noise.

[0004] In this type of silencer, the greater the amount of sound absorbing material, the greater the noise reduction effect, so a high-performance silencer requires a large space and a large amount of cost for a large amount of sound absorbing material. However, compared with the cost, the effect of reducing noise is negligible. Moreover, the position of the sound absorbing material is designed so that the discharge sound of water discharged to the drain port cannot be reduced. Summary of the invention

[0005] The present invention provides a muffler capable of reducing high frequency noise and exhaust noise generated from a water discharge port, and a vehicle including the muffler.

[0006] One embodiment of the present invention is a muffler capable of reducing high frequency noise and exhaust noise generated from a water discharge port and a vehicle including the same.

[0007] According to one embodiment of the present invention, the silencer may include: a shell having an inlet and an outlet; a perforated pipe having a plurality of through holes located in the shell; at least one baffle, wherein the at least one baffle is arranged between the shell and the perforated pipe to divide the internal space between the shell and the perforated pipe into a plurality of resonance chambers; and a cover installed in the shell to support the perforated pipe and divide the most downstream resonance chamber.

[0008] The housing may include: a first housing having an outer tube and an inner tube; and a second housing combined with the first housing, the inlet being formed at the outer tube, and the outlet being formed at the second housing.

[0009] A plurality of spacers may be provided between the outer tube and the inner tube to support the inner tube relative to the outer tube, maintain a gap between the outer tube and the inner tube, and communicate a partition space between the outer tube and the inner tube with an internal space of the housing.

[0010] The perforated tube may be spaced apart from the inner tube radially inwardly and accommodated in the first housing. A through hole may be formed in the cover. One end of the perforated tube may be connected to the inlet. The other end of the perforated tube may be connected to the through hole.

[0011] The baffle may include a first baffle, which may be located at an upstream end of the inner tube to separate a first resonance chamber formed as a space between the outer tube and the perforated tube and a second resonance chamber formed as a space between the inner tube and the perforated tube.

[0012] The first resonance chamber may include the partition space, and a frequency of noise reduced by the first resonance chamber may be lower than a frequency of noise reduced by the second resonance chamber.

[0013] The baffle may further include a second baffle located downstream of the first baffle, and the second baffle may partition an inner space between the inner tube and the perforated tube into the second resonance chamber and an auxiliary resonance chamber.

[0014] The second baffle may include at least one drainage hole, the drainage hole is formed through the housing in an axial direction, and the drainage hole may be located at a lower portion of the second baffle.

[0015] The cover may further include an extension pipe formed to protrude upstream from the inner pipe and the perforated pipe, and one end portion of the extension pipe may contact the baffle.

[0016] The extension tube may include a partition wall formed between the inner tube and the perforated tube, the partition wall extending in a direction intersecting the axis of the perforated tube, and using the partition wall, the extension tube can be divided into a first extension portion located upstream of the partition wall and a second extension portion located downstream of the partition wall.

[0017] A space between the extension pipe and the perforated pipe may be divided into a first auxiliary resonance chamber divided by the first extension portion and the partition wall and a second auxiliary resonance chamber divided by the second extension portion and the partition wall.

[0018] The volumes of the first auxiliary resonance chamber and the second auxiliary resonance chamber may be adjusted by respectively adjusting the axial lengths of the first extension portion and the second extension portion and the distances of the first extension portion and the second extension portion from the perforated tube.

[0019] Each of the cover, the partition wall, and the second extension portion may include at least one drainage hole, and the drainage hole may be provided at lower portions of the cover, the partition wall, and the second extension portion.

[0020] The plurality of through holes may be arranged in an upper region from about half of the height to a top surface in an up-down direction of the perforated pipe.

[0021] A perforation rate, which is a ratio of the area of ​​the plurality of through holes to the surface area of ​​the perforated tube, may be set within a range of 10% to 20%.

[0022] The muffler may further include an etched filter located in the housing downstream of the perforated tube and the cover to separate liquid from the fluid.

[0023] The housing may further include a drain port disposed downstream of the perforated tube and the cover, the drain port being configured to communicate with the outside.

[0024] The sound absorbing material may be located at least partially in the most downstream resonant chamber.

[0025] According to one embodiment of the present invention, a vehicle may include: an exhaust system; and a muffler disposed in the exhaust system and having a plurality of resonance chambers partitioned by a perforated pipe and at least one baffle in a housing.

[0026] The exhaust system may be connected to a humidifier of the fuel cell system.

[0027] As described above, according to one embodiment of the present invention, not only can high-frequency noise be significantly reduced in a limited space without a separate sound absorbing material, but also the absorption of moisture by the sound absorbing material can be prevented, which can effectively maintain stable noise reduction performance.

[0028] Furthermore, according to one embodiment of the present invention, since a separate sound absorbing material can be omitted, the cost can be reduced, thereby improving the competitiveness of the product.

[0029] Furthermore, according to one embodiment of the present invention, the gas-liquid separation space may be located downstream of the noise reduction space, thereby achieving an effect of reducing the discharge sound of water discharged through the drain pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above content and other features and advantages of the present invention can be more clearly understood through the following detailed description in conjunction with the accompanying drawings, wherein:

[0031] Figure 1 is a perspective perspective view showing a muffler according to one embodiment of the present invention;

[0032] Figure 2 yes Figure 1 Exploded stereogram of

[0033] Figure 3 yes Figure 1sectional view of;

[0034] Figure 4 is an exploded perspective view of a portion of a muffler according to an embodiment of the present invention;

[0035] Figure 5 yes Figure 3 an exploded perspective view of part B;

[0036] Figure 6 is a schematic diagram showing the flow of fluid in a muffler according to one embodiment of the present invention;

[0037] Figure 7 is a cross-sectional view showing a muffler according to one embodiment of the present invention; and

[0038] Figure 8 : is a graph showing evaluation of noise reduction performance obtained by manufacturing samples of a silencer according to one embodiment of the present invention and comparing with the prior art. DETAILED DESCRIPTION

[0039] In order to increase the output of the fuel cell stack and dilute the concentration of unreacted hydrogen, the fuel cell vehicle can blow air from an air compressor located upstream of the humidifier, and connect the exhaust system to the humidifier, using an air pressure control valve to adjust the internal pressure of the fuel cell stack. Therefore, when a high-speed and high-flow fluid flows through the pipeline, high-frequency noise may be generated in the exhaust system. Thus, a muffler for reducing noise can be installed in the exhaust system of the fuel cell vehicle, and in particular, a structure for reducing high-frequency noise can be used inside the muffler.

[0040] In addition, the drain pipe can be connected to the muffler to discharge air and water, so the diameter of the drain pipe can be designed to be small to prevent corrosion or contamination. Therefore, the noise generated when the fluid is discharged at high speed through the drain pipe may be loud, and this noise may flow into the interior of the fuel cell vehicle while driving.

[0041] An embodiment of the present invention includes a muffler capable of reducing not only high-frequency noise but also sound of drainage generated from a drainage port by omitting a sound absorbing material and applying a plurality of resonance chambers.

[0042] When adding reference numerals to components in each drawing, the same reference numerals are given to the same components as much as possible even if they are shown in different drawings.

[0043] In this specification, a vehicle may refer to various means of transport for moving a transported object (such as a person, an animal, or a cargo) from a starting point to a destination, for example. A vehicle is not necessarily limited to a vehicle that travels on a road or track.

[0044] However, in this specification, for the sake of convenience, the present invention is described by taking as an example a fuel cell vehicle using a fuel cell system, but the embodiments of the present invention are not necessarily limited to this, and the embodiments of the present invention can also be applied to any other vehicle equipped with an exhaust system, for example.

[0045] In addition, terms such as "first", "second", etc. may be used to describe various components. However, these terms do not necessarily limit the order, size, position, importance, etc. of the components, and are only used to distinguish one component from another.

[0046] In addition, for example, terms such as “upper,” “lower,” “top and bottom,” and the like may be used based on the direction of a vehicle or a body of the vehicle, for example.

[0047] Figure 1 is a perspective view showing a muffler according to a first embodiment of the present invention. Figure 2 yes Figure 1 Exploded three-dimensional diagram. Figure 3 yes Figure 1 Cross-sectional view of . Figure 4 According to the first embodiment of the present invention Figure 1 An exploded perspective cross-sectional view of a portion of a muffler.

[0048] The muffler according to the first embodiment of the present invention may include a housing 10 , a perforated pipe 30 , at least one baffle 40 , and a cover 50 .

[0049] The housing 10 may extend long in the axial direction, and may be formed as a cylindrical member having an inner space S1. The housing may have a cross-sectional shape, for example, a circular, elliptical, or polygonal shape.

[0050] An inlet 11 into which a fluid flows may be located at one side of the housing 10, and an outlet 12 communicating with the outside may be located at the other side of the housing 10. The inlet and the outlet may communicate with an internal space S1 in the housing 10.

[0051] In addition, on the other side of the housing 10, such as downstream of the perforated pipe 30 and the cover 50, a drain port 13 communicating with the outside can be provided to drain water from the housing. The drain port can be located at the bottom of the housing, adjacent to the outlet 12. The drain pipe 14 (see Figure 6 ) can be connected to the drain port 13 so that the water in the shell can be discharged to the outside of the shell through the drain port and the drain pipe by utilizing gravity and pressure difference.

[0052] For example, the housing 10 may be located for discharging fluid from a fuel cell stack of a vehicle to an external exhaust system. A plurality of mounting brackets 15 may be provided on an outer surface of the housing so that the housing may be stably fixed and mounted on a vehicle frame (not shown) via the mounting brackets.

[0053] For ease of manufacturing and assembly, the housing 10 may include a first housing 21 having an outer tube 17 and an inner tube 18 , and a second housing 22 coupled to the first housing.

[0054] The outer tube 17 of the first housing 21 may form a portion of the outer surface of the housing 10. The inner tube 18 may be spaced apart from the outer tube 17 at a radially inner side and form a portion of the inner surface of the housing 10.

[0055] The axial length of the inner tube 18 may be shorter than that of the outer tube 17 , and the cross-sectional area of ​​the inner tube 18 may be smaller than that of the outer tube 17 , so that the inner tube 18 may be accommodated in the outer tube 17 .

[0056] A plurality of spacers 19 may be located between the outer tube 17 and the inner tube 18 to support the inner tube relative to the outer tube and maintain a gap therebetween. The partition space S2 between the outer tube 17 and the inner tube 18 may communicate with the inner space S1 of the housing 10 to form a part of the inner space.

[0057] Each spacer 19 may be formed of, for example, a substantially plate-shaped member, and both ends of the spacer extending in the axial direction of the housing 10 may be connected and fixed to the inner surface of the outer tube 17 and the outer surface of the inner tube 18, respectively. A plurality of spacers may be distributed at a predetermined interval in the circumferential direction of the inner tube and / or the outer tube. In addition, a plurality of spacers may be formed at both ends of the inner tube in the axial direction.

[0058] The outer tube 17 and the inner tube 18 forming the first housing 21 may be coaxially arranged with each other. The inlet 11 may be formed at one side of the first housing 21, i.e., the outer tube 17. In addition, a first flange 23 extending radially outward may be formed at the opposite side of the inlet in the first housing 21, i.e., at the other end of the first housing.

[0059] The second housing 22 may be coupled to the other end of the first housing 21 to form the rest of the housing 10. The outlet 12 may be formed at one side of the second housing 22, and a second flange 24 extending radially outward may be formed at the opposite side of the outlet in the second housing 22, i.e., at the other end of the second housing.

[0060] The inlet 11 of the first shell 21 and the outlet 12 of the second shell 22 may be coaxially positioned relative to each other, but one embodiment of the present invention is not necessarily limited thereto. In addition, the drain port 13 may be formed on one side of the second shell 22. As described above, the drain port 13 may be located at the bottom of the second shell 22 forming the shell 10 in addition to being adjacent to the outlet 12.

[0061] Because moisture or water in the fluid flowing into the inlet 11 can flow to the lower part of the shell 10 by gravity and can be collected at the bottom, and because the pressure inside the shell of the muffler can be higher than the atmospheric pressure, the water can be discharged to the outside of the shell through the drain port 13 due to the pressure difference and gravity.

[0062] The first flange 23 and the second flange 24 may be fixed to each other by press-fitting, bolting, welding, etc., whereby the first shell 21 and the second shell 22 may be combined with each other to form the shell 10 .

[0063] When the silencer according to the first embodiment of the present invention is installed in the exhaust system of a fuel cell vehicle, moisture, unreacted hydrogen, unreacted air, other foreign matter, etc. generated during the power generation reaction in the fuel cell stack can flow into the first shell 21 of the shell 10 through the inlet 11 in the form of fluid.

[0064] Then, the fluid with reduced noise may flow outward from the second housing 22 of the housing 10 through the outlet 12. In addition, water separated from the fluid may be discharged to the outside of the housing through the drain port 13 and the drain pipe 14.

[0065] The perforated tube 30 may be inserted into the housing 10 and positioned to be spaced apart from the inner surface of the housing. The axial length of the perforated tube 30 may be shorter than the axial length of the housing 10, and the cross-sectional area of ​​the perforated tube 30 may be much smaller than the cross-sectional area of ​​the housing 10, so that the perforated tube may be accommodated in the housing. The perforated tube 30 may have a cross-sectional shape such as a circle, an ellipse, a polygon, etc.

[0066] Specifically, when the housing 10 includes the first housing 21 and the second housing 22, the perforated pipe 30 may have an axial length equal to or slightly shorter than the axial length of the outer pipe 17 of the first housing 21, and may have a cross-sectional area smaller than the cross-sectional area of ​​the inner pipe 18. As a result, the perforated pipe 30 may be inserted and accommodated in the first housing 21, and spaced apart from the inner pipe 18 on the radially inner side.

[0067] The perforated tube 30 may be coaxially arranged with the first shell 21, ie, the outer tube 17 and the inner tube 18. One end of the perforated tube 30 may be directly connected to the inlet 11 of the first shell 21 so that the inside of the perforated tube 30 and the inlet 11 may communicate with each other.

[0068] The perforated tube 30 may at least partially have a plurality of through holes 31, which may be radially perforated. The plurality of through holes 31 may be arranged in the upper region from approximately half of the height to the top surface in the up-down direction of the perforated tube 30. As a result, the water flowing into the perforated tube may not be discharged through the plurality of through holes, but may pass through the perforated tube 30, and then the water may flow through the bottom of the second shell 22 and be discharged to the outside of the shell 10 through the drain port 13.

[0069] Therefore, when the fluid introduced into the inlet 11 flows through the perforated tube 30, sound waves can be emitted into the space between the first shell 21 of the shell 10 and the perforated tube 30 through the plurality of through holes 31. Since the sound waves can be emitted radially from the perforated tube 30 to the first shell 21, the fluid can flow smoothly and the noise can be further reduced.

[0070] At least one baffle 40 may be interposed between the housing 10 and the perforated tube 30 to partition the plurality of resonance chambers R. For example, the baffle 40 may be formed of an annular plate and located between the housing 10 and the perforated tube 30 , extending in a direction (eg, radial direction) intersecting the axis of the perforated tube 30 .

[0071] Optionally, at least one baffle 40 may be integrally formed with the perforated tube 30. The baffle 40 may be formed in the circumferential direction to protrude from the outer surface of the perforated tube 30 and extend radially outward, and in a state where the perforated tube is inserted into the shell 10, the end of the baffle may contact the inner surface of the shell 10 to separate the plurality of resonance chambers R.

[0072] Specifically, the first baffle 41 may separate the space between the housing 10 and the perforated pipe 30 into two spaces, ie, a first resonance chamber R1 and a second resonance chamber R2 .

[0073] For example, when the shell 10 includes a first shell 21 and a second shell 22, the first baffle 41 can be configured to be adjacent to the upstream end of the inner tube 18 of the first shell 21 to separate a first resonance chamber R1 formed as a space between the outer tube 17 and the perforated tube 30 and a second resonance chamber R2 formed as a space between the inner tube 18 and the perforated tube 30.

[0074] Since the partition space S2 between the outer tube 17 and the inner tube 18 may communicate with the inner space S1 of the housing 10 , the partition space may be included in the first resonance chamber R1 .

[0075] Alternatively, in order to position the first baffle 41 , a step portion 18 a protruding radially inward may be formed at the upstream end portion of the inner tube 18 .

[0076] In addition, the second baffle 42 may be located downstream of the first baffle 41. The second baffle 42 may partition the space between the inner tube 18 and the perforated tube 30 into two spaces, ie, a second resonance chamber R2 and an auxiliary resonance chamber SR.

[0077] Alternatively, in order to position the second baffle 42 , a step 18 b may be formed on the inner surface of the inner tube 18 so that the upstream surface protrudes radially inward and the downstream surface is recessed radially outward.

[0078] In addition, the second baffle plate 42 may further include at least one drain hole 43 perforated in the axial direction of the housing 10. The drain hole 43 may be formed at the lower portion of the second baffle plate 42 to be adjacent to the portion where the second baffle plate and the step portion 18b contact. The drain hole 43 may form a water passage through which water rising at the lower portion of the second resonance chamber R2 may be discharged to the outside of the housing through the drain port 13 provided in the second housing 22 of the housing 10.

[0079] The number or shape of the baffles 40 is not necessarily limited to the above examples, and may be increased, decreased, or changed according to different designs and variations.

[0080] The cover 50 may be mounted to the housing 10 to support the other end of the perforated pipe 30 and partition the most downstream resonance chamber among the plurality of resonance chambers R. The cover may be formed of a plate having an annular shape and a predetermined or selected thickness. The cover may have a plurality of ribs 51 formed on a surface of one side to ensure rigidity.

[0081] The outer edge of the cover 50 may be formed to be press-fitted and fixed to the inner surface of the housing 10. However, the coupling method between the cover and the housing is not necessarily limited to press-fitting, and they may be coupled to each other by, for example, bolting, welding, etc.

[0082] A through hole 52 having the same shape and size as the opening of the perforated tube 30 may be formed at the center of the cover 50. The other end of the perforated tube may be directly connected to the through hole of the cover so that the inside of the perforated tube and the through hole may communicate with each other. For example, a step portion 52a or a step groove may be formed on at least one of the other end of the perforated tube 30 and one end of the through hole 52 to form a fit with each other.

[0083] The fluid flowing from the inlet 11 through the perforated tube 30 may smoothly flow through the cover 50 without hindrance or interference, and may be discharged to the outside of the housing through the outlet 12 provided in the second housing 22 of the housing 10 .

[0084] In the cover 50 , a portion of the cover 50 between the through hole 52 and the outer edge 54 may partition the most downstream resonance chamber among the plurality of resonance chambers R, such as the auxiliary resonance chamber SR, and close the separation space S2 between the outer tube 17 and the inner tube 18 .

[0085] Figure 5 yes Figure 3 An enlarged view of part B.

[0086] Optionally, the cover 50 may further include an extension pipe 55 formed to protrude upstream in a space between the first shell 21 of the shell 10 and the perforated tube 30, for example, in the auxiliary resonance chamber SR between the inner tube 18 and the perforated tube 30. The extension pipe 55 may be integrally formed with the cover 50.

[0087] The extension pipe 55 may be formed to surround a portion of the perforated pipe 30 such that when the perforated pipe is inserted into the housing 10 , one end of the extension pipe contacts the second baffle 42 , for example, to adjust the volume of the auxiliary resonance chamber SR.

[0088] Furthermore, the extension pipe 55 may include a partition wall 56 formed between the inner pipe 18 of the first housing 21 and the perforated pipe 30 , extending in a direction (eg, radial direction) intersecting the axis of the perforated pipe.

[0089] The partition wall 56 may be formed of an annular plate and formed integrally with the extension pipe 55. With the partition wall, the extension pipe 55 may be partitioned into a first extension portion 57 located upstream of the partition wall 56 and a second extension portion 58 located downstream of the partition wall 56.

[0090] In addition, the extension tube 55 can be divided into two extension parts by the partition wall 56, so that the auxiliary resonance chamber SR between the extension tube 55 and the perforated tube 30 can be divided into two auxiliary resonance chambers, namely, a first auxiliary resonance chamber SR1 divided by the first extension part 57 and the partition wall 56, and a second auxiliary resonance chamber SR2 divided by the second extension part 58 and the partition wall 56.

[0091] Alternatively, the axial lengths of the first extension portion 57 and the second extension portion 58 may be different from each other. In addition, the first extension portion 57 and the second extension portion 58 may be formed to have different radial distances from the perforated pipe 30, respectively. In other words, by adjusting the axial lengths of the first extension portion 57 and the second extension portion 58 and their radial distances from the perforated pipe 30, respectively, the volumes of the first auxiliary resonance chamber SR1 and the second auxiliary resonance chamber SR2 may be changed or adjusted.

[0092] like Figure 5 As shown, the drain hole 53 may be formed in the partition wall 56 and the second extension part 58 constituting the extension pipe 55. At least one drain hole 53 may be formed in the partition wall 56 and the second extension part 58 at the lower portion of the extension pipe 55.

[0093] Furthermore, the drainage holes 53 may be formed at the lower portion of the cover 50 at or near a portion in contact with the inner tube 18 of the first housing 21 , respectively, on the radially inner side and the radially outer side of the inner tube.

[0094] These drainage holes 53 can form a water passage so that water rising inside the second resonance chamber R2, the separation space S2 between the outer tube 17 and the inner tube 18, the auxiliary resonance chamber SR including the first auxiliary resonance chamber SR1 and the second auxiliary resonance chamber SR2, etc. can be discharged to the outside of the shell through the drainage port 13 provided in the second shell 22 of the shell 10.

[0095] The muffler according to the first embodiment of the present invention may further include an etching filter 60, which is located downstream of the perforated pipe 30 and the cover 50 in the housing 10 to separate the liquid from the fluid. Specifically, when the housing 10 includes a first housing 21 and a second housing 22, the etching filter 60 may be installed between the through hole 52 of the cover in the second housing 22 and the outlet 12.

[0096] The etching filter 60 may be formed roughly in a plate shape and may include a plurality of micropores (not shown) that allow gases such as unreacted hydrogen, unreacted air, etc. to pass through, but do not allow liquids such as moisture, water, etc. to pass through. The etching filter may be arranged obliquely in the housing 10, but the present invention is not necessarily limited thereto.

[0097] The micropores may be formed to have a size such that at least a portion of water in the fluid is separated from the fluid when the fluid passes through the micropores. For example, the diameter or width of the micropores may be in the range of about 100 to 500 μm.

[0098] In the muffler according to the first embodiment of the present invention constructed as described above, the space for reducing noise is provided at the upstream, the space for separating gas and liquid is provided at the downstream, and a cover 50 for dividing these spaces is applied. By providing the space for separating gas and liquid adjacent to the space for reducing noise, the muffler of the present invention can first remove noise from the fluid and then discharge the fluid, so that the muffler can have the advantage of reducing the discharge sound of water discharged through the drain port 13 and the drain pipe 14.

[0099] In addition, in the muffler according to the first embodiment of the present invention, the sound absorbing material can be omitted, and a plurality of resonance chambers R can be applied, and the muffler can tune each resonance chamber differently to reduce noise of a specific frequency in each resonance chamber. Therefore, the muffler of the present invention can not only significantly reduce high-frequency noise such as high-speed airflow sound, but also maintain stable noise reduction performance due to the absence of moisture absorption problem of the sound absorbing material.

[0100] Furthermore, since a separate sound absorbing material is not applied to the muffler according to the first embodiment of the present invention, an additional effect of reducing costs can be obtained, thereby improving the competitiveness of the product.

[0101] Figure 6 is a schematic diagram showing the flow of fluid in the muffler according to the first embodiment of the present invention.

[0102] When the muffler according to the first embodiment of the present invention is installed in the exhaust system of a fuel cell vehicle to reduce noise, the noise of the frequency of main concern may be high-frequency noise in the frequency band of about 1 to 3 kHz. In order to reduce such high-frequency noise, in the muffler according to the first embodiment of the present invention, by using the limited space within the first shell 21 of the shell 10 to change the number and position of the baffles 40 and the structure of the cover 50, the muffler can tune each resonance chamber R and / or the auxiliary resonance chamber SR to reduce noise of a specific frequency.

[0103] More specifically, for example, Figure 6 As shown, in the silencer according to the first embodiment of the present invention, in the first shell 21 of the shell 10, the first resonance chamber R1, the second resonance chamber R2, the first auxiliary resonance chamber SR1 and the second auxiliary resonance chamber SR2, i.e., a total of four resonance spaces can be divided and configured in sequence from upstream to downstream around the perforated pipe 30.

[0104] These resonance spaces can be substantially independently partitioned so that fluid cannot flow between the resonance spaces. Figure 6 As shown, the fluid can enter and leave the resonance space, ie, each resonance chamber R and / or each auxiliary resonance chamber SR, only through the perforated tube 30 communicating with all the resonance spaces.

[0105] The Helmholtz resonator modified to include the perforated pipe 30 may be applied to the resonance space. The Helmholtz resonator is used to absorb and resonate noise of a specific frequency and eliminate the noise by interference. The Helmholtz resonance frequency may be determined by Equation 1.

[0106] [Formula 1]

[0107]

[0108] Here, f may be the resonance frequency, c may be the sound velocity, S may be the area of ​​the through hole 31 , V may be the volume of the resonance chamber R or the auxiliary resonance chamber SR, and L may be the length of the through hole 31 , that is, the thickness of the perforated tube 30 .

[0109] According to Formula 1, for example, in order to reduce high-frequency noise using the resonance chamber R and / or the auxiliary resonance chamber SR applying a Helmholtz resonator, the volume V of the resonance chamber R or the auxiliary resonance chamber SR can be reduced, the length L of the through hole 31 can be shortened, and the area S of the through hole can be increased.

[0110] More specifically, the first resonance chamber R1 including the space between the outer tube 17 and the perforated tube 30 and the partition space S2 between the outer tube 17 and the inner tube 18 may reduce high frequency noise of, for example, about 1 kHz.

[0111] By increasing the separation space S2 to increase the volume V of the first resonance chamber R1, relatively low high-frequency noise, ie, high-frequency noise of 1 kHz, can be reduced.

[0112] The second resonance chamber R2 formed as a space between the inner tube 18 and the perforated tube 30 can reduce high-frequency noise of, for example, about 2 kHz.

[0113] Compared with the first resonance chamber R1, by increasing the number of through holes 31 of the corresponding perforated tube 30, or increasing the area of ​​the through holes, and reducing the volume V of the second resonance chamber R2, high-frequency noise higher than the resonance frequency of the first resonance chamber, that is, high-frequency noise of 2 kHz, can be reduced.

[0114] Next, the first auxiliary resonance chamber SR1 formed as a space between the first extension portion 57 of the extension pipe 55 provided in the cover 50 and the perforated pipe 30 may reduce high frequency noise of about 2.5 kHz.

[0115] By significantly increasing the number of through holes 31 of the corresponding perforated tube 30 or significantly increasing the area of ​​the through holes compared to the first resonance chamber R1 and the second resonance chamber R2, and relatively reducing the volume V of the first auxiliary resonance chamber SR1, high-frequency noise of 2.5 kHz, which is higher than the resonance frequency of the first resonance chamber and the second resonance chamber, can be reduced.

[0116] The second auxiliary resonance chamber SR2 formed as a space between the second extension portion 58 of the extension pipe 55 provided in the cover 50 and the perforated pipe 30 may reduce high frequency noise of about 3 kHz.

[0117] By significantly reducing the volume V of the second auxiliary resonance chamber SR2 compared to the first resonance chamber R1, the second resonance chamber R2 and the first auxiliary resonance chamber SR1, high-frequency noise higher than the resonance frequency of other resonance chambers or the first auxiliary resonance chamber, that is, 3 kHz high-frequency noise can be reduced.

[0118] In each resonance chamber R and / or auxiliary resonance chamber SR, for example, when a specific sound wave generated in the exhaust system of a fuel cell vehicle enters through the plurality of through holes 31 of the perforated pipe 30, the corresponding sound wave becomes a new vibration of the opposite phase of its waveform, and comes out of the resonance chamber and / or auxiliary resonance chamber. Therefore, phase cancellation may occur for a specific frequency, thereby enabling the noise in the exhaust system to be significantly eliminated or attenuated.

[0119] The through holes 31 of the perforated tube 30 can have different numbers and areas to tune the resonance frequencies corresponding to each resonance chamber R and / or each auxiliary resonance chamber SR, and the perforation ratio, which is the ratio of the area of ​​the through holes to the surface area of ​​the perforated tube, can be set in the range of about 10% to 20%.

[0120] Furthermore, in order to prevent the water accumulated in the perforated pipe 30 from flowing into the resonance chamber R or the auxiliary resonance chamber SR, as described above, the plurality of through holes 31 may be provided in the upper region of the perforated pipe from about half of the height to the top surface in the up-down direction. As a result, the water flowing into the perforated pipe is unlikely or not to be discharged through the plurality of through holes, but is able to pass through the perforated pipe, then flow through the bottom of the second housing 22, and may be discharged to the outside of the housing 10 through the drain port 13.

[0121] In addition to having a design that blocks water from entering the resonance chamber, water flowing into each resonance chamber R or each auxiliary resonance chamber SR can be discharged from each resonance chamber and each auxiliary resonance chamber through the drainage holes 43 and 53 formed in the baffle 40, the partition wall 56, the second extension portion 58, the cover 50, etc. Figure 6 As shown, the water can be discharged to the outside through the drain port 13 and the drain pipe 14 provided in the second housing 22 of the housing 10 together with the moisture separated from the gas in the etching filter 60 .

[0122] The number, shape and size of the resonance space including the first resonance chamber R1, the second resonance chamber R2, the first auxiliary resonance chamber SR1 and the second auxiliary resonance chamber SR2 are not necessarily limited to the above examples, and it should be noted that these may be added, subtracted or changed as needed.

[0123] Figure 7 is a sectional view showing a muffler according to a second embodiment of the present invention.

[0124] The muffler according to the second embodiment may include a housing 10 , a perforated pipe 30 , at least one baffle 40 , and a cover 50 .

[0125] Figure 7 The second embodiment shown is different only in that a sound absorbing material 70 is incorporated, and the remaining components may be the same as the first embodiment. Thus, when describing the silencer according to the second embodiment, the same components as those of the silencer according to the first embodiment described above will be given the same reference numerals, and a detailed description of their structure and function will be omitted.

[0126] In the muffler according to the second embodiment of the present invention, the corresponding resonance chamber may become the sound absorption chamber A by at least partially placing the sound absorbing material 70 in the most downstream resonance chamber among the plurality of resonance chambers R, for example, the auxiliary resonance chamber SR.

[0127] The sound absorption chamber A may be divided into a space between the most downstream baffle plate of at least one baffle plate 40 or a plurality of baffle plates and the cover 50 and between the inner tube 18 of the first shell 21 and the perforated tube 30. In this case, the cover 50 may be integrally formed with the perforated tube 30.

[0128] In the sound absorbing chamber A, the sound absorbing material 70 may be arranged in the upper region from about half the height to the top surface of the inner tube 18 of the first shell 21 in the up-down direction. As a result, water flowing into the sound absorbing chamber of the perforated tube 30 or the inner tube 18 can be prevented from being absorbed by the sound absorbing material or cannot be absorbed by the sound absorbing material, and the noise reduction performance can be maintained at a stable level.

[0129] As the sound absorbing material 70 , for example, a porous sound absorbing material formed of a material such as high-density polyethylene (HDPE) may be used, but the embodiments of the present invention are not necessarily limited thereto. For example, a sound absorbing material formed of glass wool or the like may be used.

[0130] At the same time, the number of through holes 31 of the perforated pipe 30 corresponding to the sound absorbing chamber A can be greatly increased, and the area of ​​the through holes can be greatly reduced, compared with the first resonance chamber R1 and the second resonance chamber R2. Similar to the first embodiment, a plurality of through holes 31 can be arranged in the upper region of the perforated pipe 30 from about half of the height to the top surface in the up-down direction.

[0131] Thus, when a fluid containing moisture, unreacted hydrogen, unreacted air, etc. flows through the perforated pipe 30, sound waves can be radiated toward the sound absorbing material 70 through the plurality of through holes 31, and the sound waves entering the sound absorbing material can be converted into heat energy through friction between gas particles and the inner surface of the pores of the sound absorbing material, thereby reducing noise.

[0132] Through such sound absorption, the silencer according to the second embodiment of the present invention can improve the noise reduction performance for high frequencies of about 2 kHz or higher.

[0133] Figure 8 : is a graph showing the evaluation of the noise reduction performance by manufacturing samples of the silencers according to the first and second embodiments of the present invention compared with the related art.

[0134] The applicant used a 3D printer to manufacture silencers according to the first and second embodiments of the present invention, and measured the transmission loss to evaluate the noise reduction performance together with a silencer according to the prior art having only a built-in porous sound absorbing material but no resonance chamber.

[0135] The transmission loss of a silencer can be defined as the ratio of the sound output incident on the silencer to the sound output transmitted through the silencer.

[0136] Check Figure 8 From the evaluation results shown, it can be seen that, in the silencers according to the first and second embodiments of the present invention, the transmission loss is improved by 10 dB or more in the frequency band of 2 kHz or less, compared with the prior art.

[0137] Therefore, by applying a resonance chamber including a perforated tube and optimizing the thickness of the perforated tube 30, the number and area of ​​the through holes 31, and / or the volume V of the resonance chamber R and / or the auxiliary resonance chamber SR, a muffler according to an embodiment of the present invention can significantly reduce noise in a specific frequency band.

[0138] As described above, according to one embodiment of the present invention, not only can high-frequency noise be significantly reduced in a limited space without a separate sound absorbing material, but also the noise reduction performance can be kept stable because there is no problem with moisture absorption of the sound absorbing material.

[0139] Furthermore, according to one embodiment of the present invention, since a separate sound absorbing material is not applied, the cost can be reduced, thereby improving the competitiveness of the product.

[0140] Furthermore, according to one embodiment of the present invention, by disposing the gas-liquid separation space downstream of the noise reduction space, it is possible to obtain an effect of reducing the discharge sound of water discharged through the drain pipe.

[0141] The above description merely illustrates the technical concept of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and variations without departing from the scope of the present invention.

[0142] Therefore, the exemplary embodiments disclosed in this specification and the accompanying drawings are not intended to limit but to illustrate the technical concepts of the present invention, and the scope of the technical ideas of the present invention is not limited by these exemplary embodiments. All technical ideas within the scope equivalent to the protection scope of the present invention can be interpreted as being included within the scope of the present invention.

Claims

1. A muffler, comprising: a housing having an inlet and an outlet; a perforated tube having a plurality of through holes disposed in the housing; at least one baffle, the at least one baffle being disposed between the shell and the perforated tube to divide an internal space between the shell and the perforated tube into a plurality of resonance chambers; as well as A cover is installed in the housing to support the perforated tube and to define a most downstream resonance chamber.

2. The muffler according to claim 1, wherein: The housing comprises: a first housing having an outer tube and an inner tube; and A second shell is combined with the first shell, the inlet is formed in the outer tube, and the outlet is formed in the second shell.

3. The muffler according to claim 2, wherein: It also includes a plurality of spacers located between the outer tube and the inner tube to support the inner tube relative to the outer tube and maintain a gap between the outer tube and the inner tube, and is configured to connect the partition space between the outer tube and the inner tube with the internal space of the shell.

4. The muffler according to claim 3, wherein: Also included is a through hole formed in the cover, the perforated tube is spaced apart from the inner tube at the radial inner side and accommodated in the first shell, the first end of the perforated tube is connected to the inlet, and the second end of the perforated tube is connected to the through hole.

5. The muffler according to claim 4, wherein: The at least one baffle includes a first baffle located at an upstream end of the inner tube to separate a first resonance chamber formed as a first resonance space between the outer tube and the perforated tube and a second resonance chamber formed as a second resonance space between the inner tube and the perforated tube.

6. The muffler according to claim 5, wherein: The first resonance chamber is configured to reduce a frequency of noise lower than a frequency of noise reduced by the second resonance chamber.

7. The muffler according to claim 5, wherein: The at least one baffle further includes a second baffle located downstream of the first baffle, the second baffle being configured to partition an inner space between the inner tube and the perforated tube into the second resonance chamber and an auxiliary resonance chamber.

8. The muffler according to claim 7, wherein: The second baffle plate includes at least one drainage hole formed through the shell along an axial direction, and the at least one drainage hole is located at a lower portion of the second baffle plate.

9. The muffler according to claim 4, wherein: The cover further includes an extension pipe formed to protrude upstream between the inner pipe and the perforated pipe, an end of the extension pipe contacting the at least one baffle.

10. The muffler according to claim 9, wherein: The extension tube includes a partition wall formed between the inner tube and the perforated tube, the partition wall extending in a direction intersecting the axis of the perforated tube, and the partition wall is configured to divide the extension tube into a first extension portion located upstream of the partition wall and a second extension portion located downstream of the partition wall.

11. The muffler according to claim 10, wherein: An internal space defined between the extension pipe and the perforated pipe is divided into a first auxiliary resonance chamber divided by the first extension portion and the partition wall and a second auxiliary resonance chamber divided by the second extension portion and the partition wall.

12. The muffler according to claim 11, wherein: Axial lengths of the first and second extending portions and distances of the first and second extending portions from the perforated tube define volumes of the first and second auxiliary resonance chambers, respectively.

13. The muffler according to claim 10, wherein: Each of the cover, the partition wall, and the second extension portion includes at least one drainage hole at a respective lower portion.

14. The muffler according to claim 1, wherein: The plurality of through holes are arranged in an upper region from about half of the height to the top surface in the up-down direction of the perforated pipe.

15. The muffler according to claim 14, wherein: A perforation ratio, which is a ratio of the area of ​​the plurality of through holes to the surface area of ​​the perforated tube, is in a range of 10% to 20%.

16. The muffler according to claim 1, wherein: Also included is an etched filter located in the housing downstream of the perforated tube and the cover, the etched filter being configured to separate liquid from fluid.

17. The muffler according to claim 16, wherein: Also included is a drain port formed in the housing downstream of the perforated tube and the cover, the drain port being configured to allow the interior space to communicate with the exterior of the housing.

18. The muffler of claim 1, wherein: Also included is a sound absorbing material located at least partially within the downstream-most resonant chamber.

19. A vehicle comprising: Exhaust system; and A muffler is provided in the exhaust system and has a plurality of resonance chambers in a housing divided by a perforated pipe and at least one baffle.

20. The vehicle of claim 19, wherein: The exhaust system is connected to a humidifier of the fuel cell system.

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