Silencing device for engine

Abstract

In the present invention, a plurality of holes (61-68) are provided in a pipe (50) disposed in a chamber communicating with an engine (10), and openings (51, 52) at the ends of the pipe (50) are closed to form a space (A4) communicating with the chamber via the plurality of holes (61-68).

Description

Technical Field

[0001] This invention relates to a muffler for engines. Background Technology

[0002] A silencer is known to include: a main body enclosed by an end plate and divided into multiple chambers by a partition plate; and a hollow tube penetrating and inserted into the end plate and the partition plate, having a through hole formed on the side, and both ends of the hollow tube being sealed (Patent Document 1). The hollow tube functions as a resonator.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 62-176416 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] In the aforementioned prior art, in order to increase the noise reduction effect of the hollow tube as a resonator, it is necessary to enlarge the through hole. However, when the through hole is enlarged, there is a problem that the frequency of the exhaust sound that is eliminated becomes higher, while the lower frequency exhaust sound cannot be eliminated.

[0008] The problem to be solved by the present invention is to provide an engine muffler that can suppress the sound pressure level of low-frequency exhaust noise.

[0009] Solution for solving the problem

[0010] The present invention provides a plurality of holes in a tube disposed in a chamber communicating with an engine, and closes the opening at the end of the tube, thereby forming a space communicating with the chamber through the plurality of holes, thereby solving the above-mentioned problem.

[0011] The effects of the invention

[0012] According to the present invention, the sound pressure level of low-frequency exhaust noise can be suppressed. Attached Figure Description

[0013] Figure 1A This is a top view showing an example of a noise reduction device according to an embodiment of the present invention.

[0014] Figure 1B yes Figure 1A Left view of the silencer device.

[0015] Figure 2A It means Figure 1A The internal cross-sectional view of the muffler is along... Figure 1B A cross-sectional view along line AA.

[0016] Figure 2B yes Figure 2A Left view of the divider.

[0017] Figure 2C yes Figure 2A A three-dimensional view of the main parts of the silencer pipe.

[0018] Figure 3 This is a cross-sectional view showing another example of a muffler according to an embodiment of the present invention.

[0019] Figure 4A This is a cross-sectional view showing another example of a muffler according to an embodiment of the present invention.

[0020] Figure 4B yes Figure 4A A three-dimensional view of the main parts of the silencer pipe.

[0021] Figure 5 This is a cross-sectional view showing another example of a muffler according to an embodiment of the present invention.

[0022] Figure 6 This is a cross-sectional view showing another example of a muffler according to an embodiment of the present invention.

[0023] Figure 7A This is a cross-sectional view showing another example of a muffler according to an embodiment of the present invention.

[0024] Figure 7B This is a cross-sectional view showing another example of a muffler according to an embodiment of the present invention.

[0025] Figure 8A This is a cross-sectional view showing another example of a muffler according to an embodiment of the present invention.

[0026] Figure 8B This is a cross-sectional view showing another example of a muffler according to an embodiment of the present invention.

[0027] Figure 8C This is a cross-sectional view showing another example of a muffler according to an embodiment of the present invention.

[0028] Figure 8D This is a cross-sectional view showing another example of a muffler according to an embodiment of the present invention. Detailed Implementation

[0029] Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. Furthermore, for ease of explanation, the front side of the vehicle's engine is defined as the frontal side. Additionally, in the figures, "front" refers to the front of the vehicle, "rear" to the rear of the vehicle, "right" to the right side of the vehicle, "left" to the left side of the vehicle, "top" to the top of the vehicle, and "bottom" to the bottom of the vehicle.

[0030] [Structure of the silencer]

[0031] Figure 1A This is a top view illustrating an example of a noise reduction device according to an embodiment of the present invention. Figure 1B yes Figure 1A The left view of the muffler shown. The muffler is a device for reducing the exhaust noise of the engine 10, and includes an exhaust pipe 20, a muffler 30, and a tailpipe 40. The engine 10 can be an internal combustion engine that produces output by burning a combustible mixture, or it can be a hybrid engine that combines an internal combustion engine and an electric motor.

[0032] The exhaust pipe 20 is a pipe that guides the exhaust gas (hereinafter also referred to as "exhaust gas") and the sound waves (hereinafter also referred to as "sound waves") of the exhaust sound of the engine 10 to the muffler 30, and is installed on the back side of the vehicle floor. For example, the exhaust pipe 20 is made by welding together multiple round pipes made of corrosion-resistant stainless steel (such as SUS409), and is mounted on the vehicle using a bracket fixed to the floor via rubber. The base end of the exhaust pipe 20 is installed in the exhaust manifold (not shown) of the engine 10, and exhaust gas and sound waves are introduced from the engine 10 to the base end of the exhaust pipe 20. On the other hand, the end of the exhaust pipe 20 is installed in the muffler 30 and communicates with the chamber of the muffler 30.

[0033] The muffler 30 is a device for reducing the temperature of exhaust gas introduced from the exhaust pipe 20 and reducing the sound pressure level of the exhaust noise, and has at least one chamber. As an example, the muffler 30 is a cylindrical hollow molded article made of corrosion-resistant stainless steel, with a cross-sectional shape such as circular, elliptical, or rectangular. The desired shape of the muffler 30 is manufactured, for example, by stamping and welding a stainless steel sheet. The muffler 30 is suspended from the back side of the vehicle floor, for example, via brackets located at both ends in the long and / or short directions. The brackets are fixed to the back side of the floor by rubber.

[0034] The tailpipe 40 is a pipe that discharges exhaust gas and sound waves to the outside of the muffler 30 (e.g., into the atmosphere). The tailpipe 40 is made of the same material as the exhaust pipe 20 and is installed to the muffler 30 using joining methods such as welding. The shape of the tailpipe 40 is not particularly limited. When the muffler 30 is connected to different subsequent mufflers, the tailpipe 40 discharges the exhaust gas and sound waves introduced into the different mufflers to the outside of the muffler 30 housing.

[0035] Implementation Method 1

[0036] use Figures 2A-2C The structure of the muffler 30 according to the first embodiment of the present invention will be described. Figure 2A It means Figure 1A The sectional view of the interior of the muffler 30 shown is along... Figure 1B A sectional view along line AA (a sectional view perpendicular to the vertical direction). For example... Figure 2AAs shown, the muffler 30 includes: a housing 31 that houses the devices constituting the muffler 30; and partition plates 32 and 33 that divide the interior of the housing 31. The shape of the housing 31 is not particularly limited, for example, it is a roughly rectangular parallelepiped.

[0037] The interior (chamber) of the housing 31 is divided into three sections by partition plates 32 and 33. Specifically, the muffler 30 has a first section A1 divided by partition plate 32, a second section A2 divided by partition plates 32 and 33, and a third section A3 divided by partition plate 33. The first section A1, defined by the housing 31 and partition plates 32, is connected to the engine 10 via the exhaust pipe 20. The second section A2, defined by the housing 31 and partition plates 32 and 33, is connected to the first section A1 via a hole 32a in partition plate 32 and to the third section A3 via a hole 33a in partition plate 33. The third section A3, defined by the housing 31 and partition plates 33, is connected to the exterior of the muffler 30 via the tailpipe 40.

[0038] Figure 2B yes Figure 2A Left view of the partition plate 32. The shape of the hole 32a in the partition plate 32 is not particularly limited, for example, it is... Figure 2B The shape is circular as shown. Furthermore, the size (opening area) of the hole 32a can be appropriately set within a range that allows for proper movement of exhaust gas and proper propagation of sound waves. The hole 32b is a hole through which the tailpipe 40 passes, and has a shape corresponding to the outer side surface of the tailpipe 40. The partition plate 33 also has the same structure as the partition plate 32. In addition, Figure 2A The partitions 32 and 33 shown may have the same structure or different structure.

[0039] exist Figure 2A In the muffler 30 shown, exhaust gas is introduced from the exhaust pipe 20 into the first section A1 (arrow B1), moves from the first section A1 to the second section A2 via the hole 32a, and moves from the second section A2 to the third section A3 via the hole 33a (arrow B2). Then, the exhaust gas that has moved to the third section A3 is introduced into the tailpipe 40 and discharged to the outside of the muffler 30 (arrow B3). Similarly, sound waves introduced from the exhaust pipe 20 into the first section A1 propagate to the first section A1, the second section A2, and the third section A3, and are discharged to the outside of the muffler 30 via the tailpipe 40. The sound pressure level of the sound waves decreases as they pass through the holes 32a and 33a due to expansion effects, etc.

[0040] Figure 2AThe muffler 30 shown is equipped with a pipe 50 (hereinafter also referred to as a "muffler pipe") in the first section A1, which communicates with the engine 10, to suppress the sound pressure level of sound waves (especially to suppress the sound pressure level of low-frequency exhaust sounds such as roaring sounds). The opening at the end of the muffler pipe 50 is sealed by a sealing member. The sealing member is not particularly limited to any member that seals the opening of the muffler pipe 50; examples include end plates, covers, etc. Figure 2A In the silencer tube 50 shown, one end opening 51 is closed by end plate 53, and the other end opening 52 is closed by end plate 54. The sealing member, in order to properly reflect sound waves inside the silencer tube 50, has at least the same rigidity as the silencer tube 50. For example, if the sealing member is an end plate or cover made of the same material as the silencer tube 50, the thickness of the end plate or cover is set to 1.5 to 3 times the thickness of the silencer tube 50.

[0041] In addition, multiple holes are provided in the silencer tube 50. Figure 2C This indicates that it is set in Figure 2A A perspective view of the main part of the hole in the silencer tube 50, omitting the illustrations of end plates 53 and 54. (See attached image.) Figure 2C As shown, eight holes 61-68 are provided on the side of the silencer tube 50, such as... Figure 2A As shown, the silencer tube 50 has a space A4 communicating with the first partition A1 via a plurality of holes 61-68. The number of holes can be set to two or more appropriate values ​​within the range where sound waves can appropriately propagate into the interior of the silencer tube 50, depending on the shape of the holes. The shape of the holes can be set to an appropriate shape within the range where sound waves can appropriately propagate into the interior of the silencer tube 50, for example, a circle. As an example, the size of the holes is set to 5% to 50% of the inner diameter of the silencer tube 50.

[0042] When the silencer tube 50 has multiple holes, the spacing between the holes can be set to a predetermined interval or less, so that the multiple holes form a group and function as a single hole. The predetermined interval can be set to an appropriate value within the range where multiple holes form a group, for example, 1 to 2 times the diameter of the hole. For example, Figure 2C The holes 61 to 68 shown are arranged at intervals less than the specified intervals, and eight holes function as one hole.

[0043] also, Figure 2A The silencer tube 50 shown is a round tube, but it can also be an elliptical tube or a square tube. Figure 2C The muffler 50 shown is straight, but it can also be bent. Furthermore, the shape of the cross-section perpendicular to the axial direction in the muffler 50 can vary depending on its position along the axial direction.

[0044] Next, the function of the muffler 30 in the first embodiment of the present invention will be explained. Figure 2AThe muffler 50 shown, while suppressing the sound pressure level of the exhaust sound introduced into the first section A1, generates a reflected wave by reflecting the sound waves (hereinafter referred to as "first sound waves") introduced into the muffler 50 from multiple holes 61-68 using end plates 53 and 54, causing the generated reflected wave to interfere with the first sound wave. Figure 2A In the silencer tube 50 shown, the reflected wave C1, which travels to the left from the positions of the plurality of holes 61-68 and is reflected by the end plate 53, and the reflected wave C2, which travels to the right from the positions of the plurality of holes 61-68 and is reflected by the end plate 54, interfere with the first sound wave. Furthermore, if at least one of the reflected waves C1 and C2 has a waveform with an opposite phase to the first sound wave, the first sound wave is canceled out.

[0045] Furthermore, the sound wave reflected by end plate 53 propagates to end plate 54 and is reflected again, forming a sound wave reciprocating between end plates 53 and 54. Similarly, the sound wave reflected by end plate 54 propagates to end plate 53 and is reflected again, forming a sound wave reciprocating between end plates 53 and 54. Moreover, the two sound waves reciprocating between end plates 53 and 54 interfere with each other, forming a standing wave C3 with the positions of end plates 53 and 54 as antinodes when it has a frequency corresponding to the distance between end plates 53 and 54 along the axial direction of the silencer tube 50. When this standing wave C3 has a waveform with an opposite phase to the first sound wave, the first sound wave is canceled out.

[0046] so, Figure 2A The silencer 50 shown cancels three exhaust sounds with frequencies corresponding to reflected waves C1, C2, and standing wave C3, respectively. The waveforms of reflected waves C1 and C2 depend on the distances from the multiple holes 61-68 to the end plates 53 and 54, while the waveform of standing wave C3 depends on the distance between the end plates 53 and 54. Therefore, the silencer is... Figure 2A The frequency of the sound wave canceled by the silencing tube 50 shown depends on the distance from the plurality of holes 61 to 68 to the end plate 53 and the distance from the plurality of holes 61 to 68 to the end plate 54.

[0047] Implementation Method 2

[0048] use Figure 3 The structure of the muffler 30 according to the second embodiment of the present invention will be described. Figure 3 This is a cross-sectional view showing the interior of the muffler 30 according to the second embodiment of the present invention. Figure 3 The silencer 30 shown, except for the positions of holes 61-68 in the silencer tube 50, is similar to... Figure 2A The silencer 30 shown is the same. Figure 3In the muffler 50 shown, a plurality of holes 61 to 68 are provided at a position closer to the end than the central portion X in the axial direction of the muffler 50. Thus, the plurality of holes provided in the muffler 50 can also be provided at a position closer to the end than the central portion X in the axial direction of the muffler 50.

[0049] Next, the function of the muffler 30 according to the second embodiment of the present invention will be explained. Figure 3 In the silencer tube 50 shown, a reflected wave C4 is formed, which travels to the left from the positions of the multiple holes 61-68 and is reflected by the end plate 53; a reflected wave C5 is formed, which travels to the right from the positions of the multiple holes 61-68 and is reflected by the end plate 54; and a standing wave C3 is formed with the positions of the end plates 53 and 54 as antinodes. That is to say, Figure 3 The muffler 50 shown cancels out three exhaust sounds with frequencies corresponding to reflected waves C4, C5, and standing wave C3, respectively. By positioning the multiple holes provided in the muffler 50 closer to the end than the central portion X in the axial direction of the muffler 50, the frequency of the exhaust sounds canceled out by reflected waves C4 and C5 can be changed.

[0050] Third Implementation Method

[0051] use Figures 4A-4B The structure of the muffler 30 according to the third embodiment of the present invention will be described. Figure 4A This is a cross-sectional view showing the interior of the muffler 30 according to the third embodiment of the present invention. Figure 4B This indicates that it is set in Figure 4A A three-dimensional view of the holes in the silencer tube 50. Furthermore, in Figure 4B The illustrations of end plates 53 and 54 are omitted.

[0052] Figure 4A The silencer 30 shown, except for the silencer pipe 50, is similar to... Figure 2A The silencer 30 shown is the same. Figure 4A The silencer pipe 50 shown extends across section 1 A1 and section 2 A2. Additionally, as... Figure 4B As shown, a first group of holes consisting of holes 61 to 68 is provided near the opening 51 of the muffler 50, and a second group of holes consisting of holes 71 to 78 is provided at the opening 51 located axially away from the end (that is, near the opening 52 of the muffler 50). Alternatively, the first group of holes 61 to 68 may be located at a first position on the muffler 50, and the second group of holes 71 to 78 may be located at a second position axially away from the first position on the muffler 50. For example, the first and second positions may be separated by a predetermined interval axially on the muffler 50, and this predetermined interval can be set to an appropriate distance corresponding to the frequency of the exhaust sound eliminated by the muffler 50.

[0053] Next, the function of the muffler 30 according to the third embodiment of the present invention will be explained. Figure 4A In the silencer tube 50 shown, for a sound wave (first sound wave) introduced into the silencer tube 50 from the plurality of holes 61 to 68, a reflected wave C6 is formed, which propagates to the left from the positions of the plurality of holes 61 to 68 and is reflected by the end plate 53, and a reflected wave C7 is formed, which propagates to the right from the positions of the plurality of holes 61 to 68 and is reflected by the end plate 54. When the first sound wave has a waveform with an opposite phase to the reflected wave C6, the first sound wave is canceled by the reflected wave C6. When a sound wave (hereinafter also referred to as "second sound wave") introduced into the silencer tube 50 from the plurality of holes 71 to 78 has a waveform with an opposite phase to the reflected wave C7, the second sound wave is canceled by the reflected wave C7. Furthermore, since the reflected waves C6 and C7 propagate inside the silencer tube 50, when the first sound wave has a waveform with an opposite phase to the reflected wave C7, the first sound wave is canceled by the reflected wave C7, and when the second sound wave has a waveform with an opposite phase to the reflected wave C6, the second sound wave is canceled by the reflected wave C6.

[0054] Similarly, in Figure 4A In the silencer tube 50 shown, for the second sound wave, a reflected wave C8 is formed that travels to the left from the positions of the plurality of holes 71-78 and is reflected by the end plate 53, and a reflected wave C9 is formed that travels to the right from the positions of the plurality of holes 71-78 and is reflected by the end plate 54. If the first sound wave has a waveform with an opposite phase to the reflected wave C8 or C9, the first sound wave is canceled by the reflected wave C8 or C9; if the second sound wave has a waveform with an opposite phase to the reflected wave C8 or C9, the second sound wave is canceled by the reflected wave C8 or C9. Furthermore, with... Figure 2A Similarly, when a standing wave C10 is formed with antinodes at the positions of end plates 53 and 54, if the first sound wave has a waveform with an opposite phase to the standing wave C10, the first sound wave is canceled by the standing wave C10; if the second sound wave has a waveform with an opposite phase to the standing wave C10, the second sound wave is canceled by the standing wave C10. Thus, by providing holes at multiple positions axially away from the muffler 50, the frequency of the exhaust sound canceled by the muffler 50 can be increased.

[0055] Implementation Method 4

[0056] use Figure 5 The structure of the muffler 30 according to the fourth embodiment of the present invention will be described. Figure 5 This is a cross-sectional view showing the interior of the muffler 30 according to the fourth embodiment of the present invention. Figure 5 The silencer 30 shown, except for the positions of holes 71-78 in the silencer tube 50, is similar to... Figure 4A The silencer 30 shown is the same. Figure 5The silencer pipe 50 shown extends across the first partition A1 and the second partition adjacent to the first partition A1. The silencer pipe 50 is provided with a first group of holes 61-68 communicating with the first partition A1 and a second group of holes 71-78 communicating with the second partition A2. Thus, when the chamber of the housing 31 is divided into multiple partitions by partition plates 32 and 33, and the silencer pipe 50 extends across the first partition A1 and the second partition A2 adjacent to the first partition A1, it is also possible to provide a first group of holes communicating with the first partition A1 and a second group of holes communicating with the second partition A2.

[0057] Next, the function of the muffler 30 according to the fourth embodiment of the present invention will be explained. Figure 5 In the silencer tube 50 shown, besides Figure 4A In addition to the reflected waves C6-C9 and the standing wave C10 shown, the exhaust sound is also canceled by the first sound wave C11 and the second sound wave C12. Specifically, since holes 61-68 are located in the first section A1 and holes 71-78 are located in the second section A2, the second sound wave has a different frequency from the first sound wave due to the pressure loss when the sound wave propagates in the hole 32a. In this case, if the second sound wave C12 has a waveform with an opposite phase to the first sound wave C11, the second sound wave C12 is canceled by the first sound wave C11; if the first sound wave C11 has a waveform with an opposite phase to the second sound wave C12, the first sound wave C11 is canceled by the second sound wave C12.

[0058] Fifth Implementation Method

[0059] use Figure 6 The structure of the muffler 30 according to the fifth embodiment of the present invention will be described. Figure 6 This is a cross-sectional view showing the interior of the muffler 30 according to the fifth embodiment of the present invention. Figure 6 The silencer 30 shown has holes 53a and 54a on the end plates 53 and 54 of the silencer tube 50, in addition to being similar to... Figure 2A The silencer 30 shown is the same. Thus, even when the openings 51 and 52 of the silencer tube 50 are closed by sealing members, at least one of the sealing members can be provided with a hole that communicates the space A4 formed by the silencer tube 50 with the chamber. The size (opening area) of the holes 53a and 54a can be set to an appropriate value within a range capable of suppressing resonance phenomena inside the silencer tube 50 caused by reflections from the end plates 53 and 54. The number and shape of the holes 53a and 54a are determined according to the set opening area.

[0060] Next, the operation of the muffler 30 according to the fifth embodiment of the present invention will be explained. Figure 6 In the silencer tube 50 shown, with Figure 2ASimilarly, the silencer tube 50 shown causes the reflected wave C1, which travels to the left from the positions of the plurality of holes 61-68 and is reflected by the end plate 53, the reflected wave C2, which travels to the right from the positions of the plurality of holes 61-68 and is reflected by the end plate 54, and the standing wave C3, which is antinode at the positions of the end plates 53 and 54, to interfere with the first sound wave. When at least one of the reflected waves C1, C2, and the standing wave C3 has a waveform with an opposite phase to the first sound wave, the first sound wave is canceled out. Furthermore, in Figure 6 In the silencing tube 50 shown, sound waves Y1 and Y2 propagate from the holes 53a and 54a of the end plates 53 and 54 to the first partition A1, thereby reducing the amplitude of the first sound wave reflected by the end plates 53 and 54 and suppressing the resonance phenomenon inside the silencing tube 50 caused by the reflected waves C1 and C2.

[0061] Implementation Method 6

[0062] use Figures 7A-7B The structure of the muffler 30 according to the sixth embodiment of the present invention will be described. Figure 7A This is a cross-sectional view showing an example of the interior of the muffler 30 according to the sixth embodiment of the present invention. Figure 7A The silencer 30 shown is different from the silencer tube 50 except that the projected area E1 of the opening 52 on the plane Z perpendicular to the axial direction of the silencer tube 50 is larger than the cross-sectional area E2 of the silencer tube 50 at the locations where the holes 61-68 are provided. Figure 2A The muffler 30 shown is the same. Additionally, Figure 7B This is a cross-sectional view showing another example of the interior of the muffler 30 according to the sixth embodiment of the present invention. Figure 7B The silencer 30 shown is different from the silencer 50 except that the projected area E3 of the opening 51 on the plane Za perpendicular to the axial direction of the silencer tube 50 is larger than the cross-sectional area E2 of the silencer tube 50 at the locations where the holes 61-68 are provided. Figure 7A The muffler 30 shown is the same. In this way, the projected area of ​​at least one opening of the muffler 50 on a plane perpendicular to the axial direction of the muffler 50 can be larger than the axially perpendicular cross-sectional area of ​​the muffler 50 at the location where the hole is provided.

[0063] Next, the operation of the muffler 30 according to the sixth embodiment of the present invention will be explained. Figure 7A and 7B In the silencer tube 50 shown, with Figure 2A Similarly, the silencer 50 shown causes the reflected wave C1 (reflected by end plate 53), the reflected wave C2 (reflected by end plate 54), and the standing wave C3 formed between end plates 53 and 54 to interfere with the first sound wave. If at least one of the reflected waves C1, C2, and the standing wave C3 has a waveform with an opposite phase to the first sound wave, the first sound wave is canceled out. However, in Figure 7AIn the silencer tube 50 shown, because the projected area E1 of the end plate 54 on plane Z is greater than that of the end plate 54, the silencer tube 50 is more efficient. Figure 2A The end plate 54 shown is large, therefore the sound pressure level of the sound waves reflected at end plate 54 is greater, and the effect of counteracting exhaust noise is greater. Similarly, in Figure 7B In the silencer tube 50 shown, because the projected area E1 of the end plate 54 on plane Z is greater than that of the end plate 54, the silencer tube 50 is more efficient. Figure 2A The end plate 54 shown is larger, and the projected area E3 of the end plate 53 on the surface Za is larger than that of the end plate 53. Figure 2A The end plate 53 shown is large, so the sound pressure level of the sound waves reflected at end plates 53 and 54 is increased, and the effect of canceling out the exhaust sound is greater.

[0064] Implementation Method 7

[0065] use Figures 8A-8D The structure of the muffler 30 according to the seventh embodiment of the present invention will be described. Figure 8A This is a cross-sectional view showing an example of the interior of the muffler 30 according to the seventh embodiment of the present invention. Figure 8A The silencer 30 shown is similar to others, except that the silencer tube 50 is a double-layered tube consisting of an inner tube 80 and an outer tube 90 disposed outside the inner tube 80. Figure 2A The silencer 30 shown is the same. Thus, the silencer pipe 50 can also have a first side member and a second side member disposed inside or outside the first side member. The first and second side members are elongated members with openings at both ends, such as pipes including round pipes, elliptical pipes, square pipes, etc. Figure 8A In the muffler 30 shown, the inner tube 80 of the round tube corresponds to the first side component, and the outer tube 90 of the round tube corresponds to the second side component. Figure 8A The outer tube 90 shown is longer than the inner tube 80. Furthermore, the first and second side members can be straight or curved, and the shape of the cross-section perpendicular to the axial direction can vary depending on the axial position. Additionally, Figure 8A The inner tube 80 shown is supported by a bracket (not shown).

[0066] When the silencer 50 has a first side member and a second side member, at least two of the following openings are closed: one opening of the first side member, another opening of the first side member, one opening of the second side member, and another opening of the second side member, so that the first side member and the second side member form a space communicating with the chamber via a plurality of holes. Which opening of the first side member and the second side member is closed depends on the configuration of the first side member and the second side member. As an example, in Figure 8AIn the silencer pipe 50 shown, end plates 83 and 84 are used to close the openings 81 and 82 of the inner pipe 80, and end plates 93 and 94 are used to close the openings 91 and 92 of the outer pipe 90, thus closing all four openings. Figure 8A As shown, four holes 85-88 are provided on the side of the inner tube 80, and two holes 95 and 96 are provided on the side of the outer tube 90. Therefore, the silencer tube 50 uses the inner tube 80, the outer tube 90, and the end plates 83, 84, 93, and 94 to form a space A4 that communicates with the first partition A1 through multiple holes 85-88, 95, and 96. Additionally, as another example, in... Figure 8A In the silencing tube 50 shown, the openings 81 and 82 of the inner tube 80 may not be closed; instead, the openings 91 and 92 of the outer tube 90 may be closed only by the end plates 93 and 94. In this case, the outer tube 90 and the end plates 93 and 94 form a space A4 that communicates with the first partition A1 via multiple holes 95 and 96.

[0067] Figure 8B This is a cross-sectional view showing another example of the interior of the muffler 30 according to the seventh embodiment of the present invention. Figure 8B The silencer 30 shown is similar to others, except that the silencer tube 50 is a double-layered tube consisting of an inner tube 80 and an outer tube 90. Figure 2A The silencer 30 shown is the same. Figure 8B The outer tube 90 shown is shorter than the inner tube 80, therefore, in Figure 8B In the configuration shown, the openings 91 and 92 of the outer tube 90 are annular in shape. Figure 8B In the silencer tube 50 shown, the openings 81 and 82 of the inner tube 80 are not closed, while the openings 91 and 92 of the outer tube 90 are closed by annular end plates 93 and 94. Additionally, four holes 85-88 are provided on the side of the inner tube 80. Therefore, Figure 8B The silencer tube 50 shown forms a space A4 that communicates with the first partition A1 via openings 81, 82 and a plurality of holes 85-88.

[0068] Figure 8C This is a cross-sectional view showing another example of the interior of the muffler 30 according to the seventh embodiment of the present invention. Figure 8C The silencer 30 shown is similar to others, except that the silencer tube 50 is a double-layered tube consisting of an inner tube 80 and an outer tube 90. Figure 2A The silencer 30 shown is the same. Figure 8C The outer tube 90 shown is shorter than the inner tube 80, therefore, in Figure 8C In the configuration shown, the opening 91 of the outer tube 90 is annular in shape. Figure 8CIn the silencer tube 50 shown, the opening 82 of the inner tube 80 is closed by the end plate 84, and the openings 91 and 92 of the outer tube 90 are closed by the end plates 93 and 94. Additionally, four holes 85-88 are provided on the side of the inner tube 80. Therefore, Figure 8C The silencer tube 50 shown forms a space A4 that communicates with the first partition A1 via an opening 81 and a plurality of holes 85-88.

[0069] Figure 8D This is a cross-sectional view showing another example of the interior of the muffler 30 according to the seventh embodiment of the present invention. Figure 8D The silencer 30 shown, except for the positions of the holes 85-88 in the inner tube 80, the closed state of the openings 81 and 82, and the position of the inner tube 80 relative to the outer tube 90, is similar to... Figure 8C The silencer 30 shown is the same. Figure 8D In the silencer tube 50 shown, the opening 81 of the inner tube 80 is closed by the end plate 83, and the openings 91 and 92 of the outer tube 90 are closed by the end plates 93 and 94. Furthermore, four holes 85 to 88 are provided on the side of the inner tube 80 at positions where the outer tube 90 does not exist in the radial direction of the inner tube 80. Therefore, Figure 8D The silencer tube 50 shown forms a space A4 that communicates with the first partition A1 via an opening 82 and a plurality of holes 85-88.

[0070] Next, the operation of the muffler 30 according to the seventh embodiment of the present invention will be explained. Figure 8A In the silencer tube 50 shown, a reflected wave D1 is formed after being introduced into the silencer tube 50 from holes 95 and 96 and reflected by the left end plate 93; a reflected wave D2 is formed after being introduced into the silencer tube 50 from holes 95 and 96 and reflected by the right end plate 94; and a standing wave D3 is formed with the end plates 93 and 94 at antinodes. When the sound waves introduced from holes 95 and 96 have a waveform with an opposite phase to at least one of the reflected waves D1, D2, and the standing wave D3, the sound waves introduced from holes 95 and 96 are canceled out. Furthermore, the sound waves introduced into the silencer tube 50 from holes 95 and 96 propagate into the interior of the inner tube 80 via holes 85 to 88, forming a reflected wave D4 reflected by the left end plate 83 and a reflected wave D5 reflected by the right end plate 84. The reflected waves D4 and D5 reach holes 85 to 88 and are introduced between the inner tube 80 and the outer tube 90, reaching holes 95 and 96. Furthermore, when the sound waves arriving at holes 95 and 96 have waveforms with opposite phases to the sound waves introduced from holes 95 and 96, the sound waves introduced from holes 95 and 96 are canceled out. In this way, by making the muffler 50 a double-layered tube, it is possible to reduce the frequency of the exhaust sound canceled out by the muffler 50 while suppressing the lengthening of the muffler 50.

[0071] exist Figure 8BIn the silencer tube 50 shown, a reflected wave D1 is formed after being introduced into the silencer tube 50 from holes 85-88 and reflected by the left end plate 93; a reflected wave D2 is formed after being introduced into the silencer tube 50 from holes 85-88 and reflected by the right end plate 94; and a standing wave D3 is formed with the end plates 93 and 94 at antinodes. When the sound waves introduced from holes 85-88 have a waveform with an opposite phase to at least one of the reflected waves D1, D2, and the standing wave D3, the sound waves introduced from holes 85-88 are canceled out. Furthermore, when sound waves introduced from at least one of openings 81 and 82 are introduced through holes 85-88 between the inner tube 80 and the outer tube 90, reflected at end plates 93 and 94 to reach holes 85-88, and introduced into the inner tube 80 to reach openings 81 and 82, when they have a waveform with an opposite phase to the sound waves introduced from openings 81 and 82, the sound waves introduced from openings 81 and 82 are canceled out. In this way, by setting the muffler 50 as a double-layered tube, even a short tube can extend the path of the reflected wave, thereby reducing the frequency of the exhaust sound canceled by the muffler 50 while suppressing the lengthening of the muffler 50.

[0072] exist Figure 8C In the silencer tube 50 shown, a reflected wave D1 is formed after being introduced into the silencer tube 50 from holes 85-88 and reflected by the left end plate 93; a reflected wave D2 is formed after being introduced into the silencer tube 50 from holes 85-88 and reflected by the right end plate 94; and a standing wave D3 is formed with the end plates 93 and 94 at antinodes. When the sound waves introduced from holes 85-88 have a waveform with an opposite phase to at least one of the reflected waves D1, D2, and the standing wave D3, the sound waves introduced from holes 85-88 are canceled out. Furthermore, in Figure 8C In the silencer tube 50 shown, a reflected wave D6 is also formed, which is introduced into the inner tube 80 from the opening 81 and reflected by the end plate 84 on the right side. When the sound waves introduced from the holes 85 to 88 have a waveform with the opposite phase to the reflected wave D6, the sound waves introduced from the holes 85 to 88 are canceled out.

[0073] exist Figure 8D In the silencer tube 50 shown, a reflected wave D7 is formed after being introduced into the silencer tube 50 from holes 85-88 and reflected by the left end plate 83; a reflected wave D8 is formed after being introduced into the silencer tube 50 from holes 85-88 and reflected by the right end plate 94; and a standing wave D9 is formed with the end plates 83 and 94 at antinodes. When the sound waves introduced from holes 85-88 have a waveform with an opposite phase to at least one of the reflected waves D7, D8, and the standing wave D9, the sound waves introduced from holes 85-88 are canceled out. Furthermore, in Figure 8DIn the silencer tube 50 shown, sound waves reflected by end plate 94 are reflected by end plate 93 to form reflected wave D10. When the sound waves introduced through holes 85-88 have a waveform with an opposite phase to the reflected wave D10, the sound waves introduced through holes 85-88 are canceled out. Furthermore, sound waves introduced through any of holes 85-88 reach opening 82 and are introduced into the outer tube 90, reach end plate 93 of the outer tube 90 and are reflected, then reach opening 82 again and are introduced into the inner tube 80, reaching holes 85-88. And when the sound waves reaching holes 85-88 have a waveform with an opposite phase to the sound waves introduced through holes 85-88, the sound waves introduced through holes 85-88 are canceled out. Thus, in Figures 8B-8D The silencer tube 50 shown also has... Figure 8A Similarly, by making the muffler 50 a double-layered tube, even a short tube can extend the path of the reflected wave, thereby reducing the frequency of the exhaust sound canceled by the muffler 50 while suppressing the lengthening of the muffler 50.

[0074] Up to this point, various embodiments of the muffler 30 have been described. The first to seventh embodiments described above can also be combined with other embodiments. For example, the first embodiment can also be combined with at least one of the second to seventh embodiments. The same applies to the second to seventh embodiments.

[0075] [Embodiments of the Invention]

[0076] According to this embodiment, an engine muffler is provided, comprising a chamber communicating with an engine 10 and a pipe 50 disposed in the chamber. The pipe 50 is provided with a plurality of holes, and the opening at one end of the pipe 50 is closed. The pipe 50 forms a space A4 communicating with the chamber through the plurality of holes. This enables the suppression of the sound pressure level of low-frequency exhaust noise.

[0077] In the engine muffler of this embodiment, a plurality of holes are provided at a position closer to the end than the central portion X in the axial direction of the pipe 50. This allows for a change in the frequency of the exhaust sound that is canceled out by reflected waves.

[0078] In the engine muffler of this embodiment, a first group of the plurality of holes is provided at a first position of the pipe 50, and a second group of the plurality of holes is provided at a second position away from the first position in the axial direction of the pipe 50. This increases the frequency of the exhaust noise canceled by the muffler pipe 50.

[0079] In the engine muffler of this embodiment, the chamber is divided into multiple partitions, and the pipe 50 extends across a first partition A1 and a second partition A2 adjacent to the first partition A1. The pipe 50 is provided with a first group of multiple holes communicating with the first partition A1 and a second group of multiple holes communicating with the second partition A2. This allows for a further increase in the frequency of the exhaust noise canceled by the muffler pipe 50.

[0080] In the engine muffler of this embodiment, the opening of the pipe 50 is closed by a sealing member, and at least one of the sealing members is provided with a hole that communicates the space A4 with the chamber. This suppresses resonance inside the muffler pipe 50 caused by reflected waves C1 and C2.

[0081] In the engine muffler of this embodiment, the projected areas E1 and E3 of at least one of the openings on planes Z and Za perpendicular to the axial direction of the pipe 50 are larger than the cross-sectional area E2 of the pipe 50 perpendicular to the axial direction at the location where the hole is provided. This increases the effectiveness in suppressing exhaust noise.

[0082] In the engine muffler of this embodiment, the pipe 50 includes a first side member and a second side member disposed inside or outside the first side member. At least two of the openings of the first side member, the other opening of the first side member, the first opening of the second side member, and the other opening of the second side member are closed, so that the first side member and the second side member form a space A4 communicating with the chamber via a plurality of holes. This allows for the suppression of increasing the size of the muffler pipe 50 while increasing the frequency of the exhaust noise canceled by the muffler pipe 50.

[0083] Explanation of reference numerals in the attached figures

[0084] 10. Engine; 20. Exhaust pipe; 30. Muffler; 31. Housing; 32, 33. Partition plate; 32a, 32b, 33a. Hole; 40. Tailpipe; 50. Pipe (muffler pipe); 51, 52. Opening; 53, 54. End plate; 53a, 54a. Hole; 61, 62, 63, 64, 65, 66, 67, 68, 71, 72, 73, 74, 75, 76, 77, 78. Hole; 80. Inner pipe; 81, 82. Opening; 83, 84. End plate; 85, 86, 87, 88. Hole; 90. Outer side. Pipe; 91, 92, Opening; 93, 94, End plate; 95, 96, Hole; A1, Section 1; A2, Section 2; A3, Section 3; A4, Space; B1, B2, B3, Arrow; C1, C2, C4, C5, C6, C7, Reflected wave; C3, C10, Standing wave; C8, C9, Sound wave; C11, First sound wave; C12, Second sound wave; D1, D2, D4, D5, D6, D7, D8, D10, Reflected wave; D3, D9, Standing wave; X, Central part; Y1, Y2, Sound wave; Z, Za, Surface.

Claims

1. A silencer for an engine, wherein, The engine's muffler features: The chamber, which is connected to the engine; and The tube, which is disposed in the chamber, The tube is provided with multiple holes, the openings at the ends of the tube are closed, and the tube forms a space that communicates with the chamber through the multiple holes.

2. The engine muffler according to claim 1, wherein, The plurality of holes are located closer to the end than the central portion of the tube in the axial direction.

3. The engine muffler according to claim 1 or 2, wherein, A first group of the plurality of holes is disposed at a first position of the tube, and a second group of the plurality of holes is disposed at a second position away from the first position in the axial direction of the tube.

4. The engine muffler according to any one of claims 1 to 3, wherein, The chamber is divided into multiple zones. The pipe extends across the first partition and the second partition adjacent to the first partition. The pipe is provided with a first group of holes communicating with the first partition and a second group of holes communicating with the second partition.

5. The engine muffler according to any one of claims 1 to 4, wherein, The opening of the pipe is closed by a sealing member. At least one of the plurality of said enclosing members is provided with the hole that communicates the space with the chamber.

6. The engine muffler according to any one of claims 1 to 5, wherein, The projected area of ​​at least one of the openings on a plane perpendicular to the axial direction of the tube is larger than the cross-sectional area of ​​the tube perpendicular to the axial direction at the location where the hole is provided.

7. The engine muffler according to any one of claims 1 to 6, wherein, The tube includes a first side member and a second side member disposed on the inner or outer side of the first side member. At least two of the openings of the first side member, the other opening of the first side member, the first opening of the second side member, and the other opening of the second side member are closed to form a space in which the first side member and the second side member communicate with the chamber via the plurality of holes.

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