Silencer for engine and exhaust pipe for engine

Abstract

Provided is a muffler (30) for an engine, the muffler (30) comprising: a first chamber (31); and a closed tube (50) that communicates with the first chamber (31) via the open end (51) and communicates with the second chamber (60) via the first opening (Z1) in the side surface (53). Furthermore, provided is an exhaust pipe (20) for an engine, the exhaust pipe (20) comprising: a main pipe; and a closed tube (50) that communicates with the main tube via an open end (71) and communicates with the fourth chamber (81) via a third opening (Z3) in the side surface (73).

Description

Technical Field

[0001] This invention relates to a muffler for an engine and an exhaust pipe for an engine. Background Technology

[0002] A silencer is known to have a gas passage pipe connected to a bent branch passage, the front end of which is blocked and has a length determined by the resonant frequency (Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Publication No. 62-126215 Summary of the Invention

[0004] In the aforementioned prior art, since the length of the branch path is determined based on the resonant frequency, there is a problem that the length of the branch path becomes longer and the noise reduction device becomes larger, especially when silencing low-frequency sounds.

[0005] The problem to be solved by the present invention is to provide an engine muffler and an engine exhaust pipe that can suppress the large-scale muffler device.

[0006] The present invention solves the above-mentioned problem by using a closed tube that communicates with the first cavity via an open end and with the second cavity via an opening on the side.

[0007] The effects of the invention

[0008] According to the present invention, it is possible to suppress the large-scale development of silencers. Attached Figure Description

[0009] Figure 1 This is a top view showing an example of a noise reduction device according to an embodiment of the present invention.

[0010] Figure 2 yes Figure 1 Left side view of the silencer device.

[0011] Figure 3 It means Figure 1 The sectional view of the closed tube and the second cavity is along... Figure 1 A cross-sectional view along line AA.

[0012] Figure 4 It is Figure 3 An enlarged cross-sectional view of the area around the first opening shown.

[0013] Figure 5 It means Figure 1 The sectional view of the closed tube and the second cavity is along... Figure 3 A cross-sectional view of the BB line.

[0014] Figure 6 This is a cross-sectional view showing another example of the second cavity according to an embodiment of the present invention.

[0015] Figure 7 This is a top view showing the main parts of other examples of a muffler according to embodiments of the present invention.

[0016] Figure 8 It means Figure 7 A cross-sectional view of the main parts of the closed tube and the third cavity, along... Figure 7 A sectional view of the main part of the CC line.

[0017] Figure 9 This is a top view showing other examples of a noise reduction device according to an embodiment of the present invention.

[0018] Figure 10 It means Figure 9 Rear view of the main parts of the closed tube and cavity.

[0019] Figure 11 It means Figure 9 A top view of the main parts of the closed tube and cavity.

[0020] Figure 12 It means Figure 9 The sectional view of the closed tube and cavity is along... Figure 9 A cross-sectional view of the DD line.

[0021] Figure 13 It means Figure 1 The diagram showing the function of the cavity (Figure 1).

[0022] Figure 14 It means Figure 1 The diagram showing the function of the cavity (Figure 2).

[0023] Figure 15 It means Figure 9 The diagram showing the function of the cavity (Figure 1).

[0024] Figure 16 It means Figure 9 The diagram showing the function of the cavity (Figure 2). Detailed Implementation

[0025] 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.

[0026] [Structure of the silencer]

[0027] Figure 1 This is a top view showing an example of a noise reduction device according to an embodiment of the present invention. Figure 2 yes Figure 1 The image shows a left-side view of the muffler. The muffler is a device that reduces the exhaust noise of an internal combustion engine, i.e., engine 10, which produces output by burning a combustible mixture. It includes an exhaust pipe 20, a muffler 30, and a tailpipe 40. Furthermore, engine 10 can also be a hybrid engine that combines an internal combustion engine and an electric motor.

[0028] 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) from the engine 10 to the muffler 30, and is arranged on the underside of the vehicle's floor. For example, the exhaust pipe 20 is manufactured by welding together multiple round pipes made of corrosion-resistant stainless steel (such as SUS409), and is mounted to the vehicle via a bracket fixed to the floor with rubber. The base of the exhaust pipe 20 is mounted to the exhaust manifold of the engine 10, and exhaust gas and sound waves are introduced from the engine 10. On the other hand, the end of the exhaust pipe 20 is mounted to the muffler 30 and communicates with the cavity of the muffler 30.

[0029] 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 cavity. As an example, the muffler 30 is a cylindrical hollow molded article made of corrosion-resistant stainless steel, with a cross-sectional shape that is circular, elliptical, rectangular, etc. The desired shape of the muffler 30 is, for example, manufactured by stamping and welding a stainless steel sheet. The muffler 30 is suspended from the underside of the vehicle floor, for example, via brackets provided at both ends in the long and / or short directions. The brackets are fixed to the underside of the floor by rubber.

[0030] The tailpipe 40 is a pipe that discharges exhaust gases 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. Furthermore, when the muffler 30 is connected to subsequent mufflers, the tailpipe 40 discharges exhaust gases and sound waves to the outside of the frame of the muffler 30.

[0031] The muffler 30 is an engine muffler. To suppress the increase in the size of the muffler and improve its vehicle-mountability, it has a closed pipe 50 and a second chamber 60. The closed pipe 50 is a pipe (e.g., a round pipe) with an open end and a closed end. It cancels out sound waves with a desired frequency by reflecting the waves reflected at the closed end. The closed pipe 50 is made of the same material as the exhaust pipe 20 and is installed to the muffler 30 using joining methods such as welding. On the other hand, the second chamber 60 is a space separated by a frame, which is made of, for example, corrosion-resistant stainless steel.

[0032] use Figure 3 The closed tube 50 and the second cavity 60 are explained. Figure 3 It is along Figure 1 A cross-sectional view along line AA. (e.g.) Figure 3 As shown, the muffler 30 has a first chamber 31. The shape of the first chamber 31 is not particularly limited, as long as it can reduce the sound pressure level of the exhaust sound to the range specified by regulations. On the other hand, the closed pipe 50 has an open end 51, a closed end 52, and a side 53. The closed pipe 50 communicates with the first chamber 31 via the open end 51 and with the second chamber 60 via a first opening Z1 on the side 53. Furthermore, in the accompanying drawings, the open end is shown by a dashed line, and the closed end is shown by a solid line.

[0033] The shape of the second cavity 60 is designed to not suppress the introduction of sound waves into the second cavity 60. Specifically, the cross-sectional area of ​​at least one surface within the second cavity 60 (particularly, further outward than the first opening Z1) of the first section S1 obtained by cutting the second cavity 60 with a plane perpendicular to the first normal L1 passing through the center Y1 of the first opening Z1 of the tube axis X1 of the closed tube 50 is greater than the area of ​​the first opening Z1. The tube axis X1 of the closed tube 50 refers to the central axis of the closed tube 50. The normal to the tube axis X1 refers to the line orthogonal to the tube axis X1. Figure 3 The middle line is a straight line extending vertically along the attached diagram. "Outer than the first opening Z1" refers to the side of the tube axis X1 that is farther from the closed tube 50 relative to the first opening Z1. Figure 3 The middle cavity is located higher than the first opening Z1. Furthermore, the second cavity 60 is a closed space except for the first opening Z1, and does not have any openings other than the first opening Z1.

[0034] The center Y1 of the first opening Z1 is set as the center of the projected image after projecting the first opening Z1 onto the projection plane, and the area of ​​the first opening is set as the area of ​​the projected image. Figure 4 The method for calculating the center Y1 and the area of ​​the first opening is explained. Figure 4 It is Figure 3 An enlarged cross-sectional view of the area surrounding the first opening Z1, shown below, the first opening Z1 being composed of... Figure 4 The end faces E1 and E2 shown are determined. For example... Figure 4 As shown, the center Y1 of the first opening Z1 is set as the center of the projection onto a projection plane P that is orthogonal to at least one of the end faces E1 and E2, and the area of ​​the first opening is set as the area of ​​the projection onto the projection plane P. Furthermore, Figure 4 The projection plane P shown is parallel to the vehicle's left-right (and front-back) directions; therefore, Figure 3 The area of ​​the first opening Z1 shown is the same as the area when the first opening Z1 is viewed from above.

[0035] Figure 5 It is along Figure 3 The sectional view along line BB is a top view of the first section S1 and the first opening Z1. As described above, since the area of ​​the first opening Z1 viewed from above is the same as the area of ​​the first opening, therefore, in Figure 5 The lightly shaded area marked in the middle corresponds to the area T1 of the first opening Z1. Figure 5 The dark shaded area marked in the middle corresponds to the cross-sectional area of ​​the first section S1. Therefore, as... Figure 5 As shown, the cross-sectional area of ​​the first section S1 is greater than the area T1 of the first opening Z1.

[0036] The shape of the second cavity 60 is not particularly limited, as long as the cross-sectional area of ​​the first section S1 of at least one face is greater than the area T1 of the first opening. For example, to facilitate the propagation of sound waves into the second cavity 60, it can also be as follows: Figure 3 As shown in the second cavity 60, the cross-sectional area of ​​the entire first section S1 is made larger than the area T1 of the first opening. Alternatively, for the same purpose, the cross-sectional area of ​​the first section S1 can be made to increase as it moves away from the first opening Z1, within a range from the first opening Z1 to a position that is a predetermined distance away from the first opening Z1 along the first normal L1.

[0037] Figure 6 Is with Figure 3 Similarly along Figure 1 A cross-sectional view of line AA, but Figure 3 The second cavity 60 of the cuboid shown is replaced with Figure 6 The second cavity 60a of the sphere shown. In Figure 6 In the second cavity 60a shown, the cross-sectional area of ​​the first section S1a increases as it moves away from the first opening Z1 within a range R from the first opening Z1 to a position along the first normal L1 that is a predetermined distance away from the first opening Z1. The predetermined distance can be set to an appropriate value within a range where the second cavity 60a can be mounted in a vehicle.

[0038] The sound wave introduced from the exhaust pipe 20 into the first chamber 31 (specifically, the pressure variation of the sound wave) is propagated from the open end 51 into the interior of the closed pipe 50, reflected at the closed end 52, and output from the open end 51. The waveform of the sound wave changes during its propagation from the closed pipe 50 and the second chamber 60 (specifically, the phase of the waveform is delayed). In the case where the reflected wave output from the open end 51 has a waveform with the opposite phase to the sound wave, the reflected wave cancels out the sound wave in the first chamber 31.

[0039] The effect of delaying the phase of the sound wave increases with the length of the closed tube 50 and with the ease with which the sound wave (specifically, the pressure variation of the sound wave) propagates to the second cavity 60. That is, the effect of delaying the phase of the waveform increases with the area of ​​the first opening T1, and with a fixed first opening area T1, increases with the number of first openings Z1, increases with the volume of the second cavity 60, and increases with the cross-sectional area of ​​the first section S1. Therefore, the specific length of the closed tube 50, the area of ​​the first opening T1, the number of first openings Z1, the volume of the second cavity 60, and the cross-sectional area of ​​the first section S1 are determined based on the frequency (desired frequency) of the sound wave to be canceled.

[0040] exist Figure 1 In the silencer device shown, the closed tube 50 protrudes to the outside of the silencer 30, but it can also be as follows: Figure 7 As shown, the closed tube 50 is placed inside the silencer 30a. Figure 7 This is a top view of the main part of an example of a muffler 30a having an internal closed tube 50. The muffler 30a has a frame 32 that houses the equipment constituting the muffler 30a, and partitions 33, 34, 35, and 36 that divide the interior of the frame 32. The frame 32 is generally cuboid in shape. Figure 7 The top surface of frame 32 is not shown. Furthermore, a roughly cuboid shape is an example of the shape of frame 32; the shape of frame 32 is not particularly limited.

[0041] exist Figure 7 The silencer 30a shown is divided into multiple chambers by partitions 33, 34, 35, and 36. The silencer 30a has a first chamber 31a separated by partition 33, a second chamber 60b separated by partitions 33 and 34, a first chamber 31b separated by partitions 34 and 35, a third chamber 61 separated by partitions 35 and 36, and a first chamber 31c separated by partition 36. In the silencer 30a, the first chambers 31a, 31b, 31c, the second chamber 60b, and the third chamber 61 are formed by a frame 32 and partitions 33, 34, 35, and 36.

[0042] The first chamber 31b is connected to the end of the exhaust pipe 20, where exhaust gas and sound waves are introduced. The muffler 30a has connecting pipes 37 and 38 that directly connect the different chambers to each other. The first chambers 31b and 31c, adjacent to the third chamber 61, are connected by the connecting pipe 37 located within the third chamber 61. Furthermore, the first chambers 31a and 31c are connected by the connecting pipe 38 passing through the third chamber 61, the first chamber 31b, and the second chamber 60b. The muffler 30a also has a tailpipe 40 that discharges exhaust gas to the outside. The tailpipe 40 has an inner end 41 located within the first chamber 31a and connected to the open end 51 of the closed pipe 50, and an outer end 42 located outside the muffler 30a.

[0043] Exhaust gas introduced from exhaust pipe 20 into chamber 31b (arrow F1) is introduced from chamber 31b into chamber 31c via connecting pipe 37 (arrow F2). The exhaust gas introduced into chamber 31c moves within chamber 31c (arrow F3) and is introduced from chamber 31c into chamber 31a via connecting pipe 38 (arrow F4). The exhaust gas introduced into chamber 31a moves within chamber 31a (arrow F5). Then, the exhaust gas is introduced from inner end 41 into tailpipe 40 and discharged into the atmosphere from outer end 42 via tailpipe 40 (arrow F6).

[0044] As indicated by arrows F1 to F6, exhaust gas is not introduced into chambers 60b and 61. Therefore, a temperature difference is generated between chambers 31a, 31b, and 31c where exhaust gas is introduced and chambers 60b and 61 where exhaust gas is not introduced. This temperature difference suppresses the concentration of thermal stress on a portion of the frame 32. Therefore, in the muffler 30a, the position of chamber 61 can be set such that the center of the frame 32 relative to the tube axis of the closed tube 50 is located opposite to chamber 60b. For example, if position Q is defined as the center of the frame 32 along the tube axis X1 of the closed tube 50, then chambers 60b and 61 are positioned opposite each other relative to position Q.

[0045] The closed tube 50 has an open end 51, a closed end 52, and a side 53. It communicates with the first cavity 31a via the open end 51 and with the second cavity 60b via the first opening Z1 of the side 53. Additionally, in the silencer 30a, it also connects with… Figure 3 Similarly, in the silencing device shown, the cross-sectional area of ​​at least one surface further outward than the first opening Z1 in the first cross-section obtained by cutting the second cavity 60b with a plane perpendicular to the first normal passing through the center of the first opening Z1 in the normal of the tube axis X1 of the closed tube 50 is larger than the area of ​​the first opening Z1. Furthermore, the position of the opening end 51 of the closed tube 50 is set closer to the inner end 41 than the end of the tube other than the closed tube 50 that communicates with the inner end 41 of the tail tube 40. For example, [the following text is incomplete and requires further context to translate accurately]. Figure 7 The position of the opening end 51 shown is set closer to the inner end 41 than the end of the connecting tube 38 located in the first cavity 31a.

[0046] Figure 7 The closed tube 50 shown has a second opening Z2 located further away from the opening end 51 than the first opening Z1, and communicates with the third cavity 61 via the second opening Z2. In order to increase the phase delay effect of the waveform on the side closer to the opening end 51, the volume of the third cavity 61 is smaller than the volume of the second cavity 60b. The volume of the third cavity 61 can also be reduced by providing connecting tubes 37 and 38 within the third cavity 61.

[0047] Figure 8 It means Figure 7 The main section view of the closed tube 50 and the third cavity 61 is along... Figure 7 A partial cross-sectional view of the CC line. In the third cavity 61, similarly to the second cavity 60b, the cross-sectional area of ​​at least one surface within the third cavity 61 (particularly, further outward than the second opening Z2) in the second section S2 obtained by cutting the third cavity 61 with a plane perpendicular to the second normal L2 passing through the center Y2 of the second opening Z2 in the normal to the tube axis X1 of the closed tube 50 is greater than the area of ​​the second opening of the second opening Z2. The center Y2 is determined by the same method as the center Y1, and the area of ​​the second opening is determined by the same method as the area of ​​the first opening. Furthermore, the third cavity 61 is a space that is closed except for the second opening Z2 and does not have any openings other than the second opening Z2.

[0048] return Figure 7 ,exist Figure 7 The lightly shaded area corresponds to the area T2 of the second opening Z2, and the darkly shaded area corresponds to the cross-sectional area of ​​the second section S2. For example... Figure 7 As shown, the cross-sectional area of ​​the second section S2 is greater than the area T2 of the second opening Z2. Furthermore, regarding the shape of the third cavity 61, it is not particularly limited as long as the cross-sectional area of ​​the second section S2 of at least one face is greater than the area T2 of the second opening; it can also be the same shape as the second cavities 60, 60a, and 60b. Moreover, similarly to the case of the second cavity 60, the tube length of the closed tube 50, the area T2 of the second opening, the number of second openings Z2, the volume of the third cavity 61, and the cross-sectional area of ​​the second section S2 are set according to the frequency (desired frequency) of the sound wave to be canceled.

[0049] In the silencer 30a, the position of the first opening Z1 can correspond to the position of the center of the second cavity 60b along the tube axis X1 of the closed tube 50, and the position of the second opening Z2 can correspond to the position of the center of the third cavity 61 along the tube axis. For example, Figure 7 The first opening Z1 is positioned at the midpoint of partitions 33 and 34 (equidistant from partitions 33 and 34), and the second opening Z2 is positioned at the midpoint of partitions 35 and 36 (equidistant from partitions 35 and 36). This suppresses resonance generated inside the cavities (e.g., the second cavity 60b and the third cavity 61). Furthermore, to suppress resonance inside the second cavity 60b and the third cavity 61, sound-absorbing material (such as glass fiber) can be provided inside at least one of the second cavity 60b and the third cavity 61.

[0050] exist Figure 1 In the silencing device shown, the closed pipe 50 is connected to the silencer 30, but as Figure 9 As shown, when the closed pipe 70 is connected to the exhaust pipe 20, the sound pressure level of the exhaust sound can also be suppressed. Figure 9 This is a top view showing other examples of the silencing device according to this embodiment. Figure 10 It means Figure 9 Rear view of the main parts of the exhaust pipe 20, the closed pipe 70, and the cavity 80 of the silencer shown. Figure 9 The exhaust pipe 20 shown has a main pipe leading to the muffler 30 and a branch pipe, i.e., a closed pipe 70, branching off from the main pipe. For example... Figure 10 As shown, the exhaust pipe 20 and the closed pipe 70 are round pipes, and the cavity 80 is cylindrical.

[0051] use Figures 11 to 12 The closed tube 70 and the cavity 80 are explained. Figure 11 It means Figure 9 Top view of the main parts of the closed tube 70 and the cavity 80. Figure 12 It is along Figure 9 A cross-sectional view of the DD line. Furthermore, in Figure 11 In the middle, the upper half of cavity 80 is not displayed.

[0052] like Figure 11 As shown, the closed tube 70 has an open end 71, a closed end 72, and a side 73. The cavity 80 is divided into a fourth cavity 81, a cavity 82, and a fifth cavity 83. The closed tube 70 communicates with the main tube via the open end 71 and with the fourth cavity 81 via the third opening Z3 on the side 73. In addition, the closed tube 70 has a fourth opening Z4 located further away from the open end 71 than the third opening Z3, and communicates with the fifth cavity 83, which has a smaller volume than the fourth cavity 81, via the fourth opening Z4.

[0053] The shapes of cavities 4 (81) and 5 (83) are the same as those of cavity 2 (60), designed to not suppress the introduction of sound waves into the cavities. Specifically, as... Figure 12 As shown, the cross-sectional area of ​​at least one face within the fourth cavity 81 (particularly, further outward than the third opening Z3) of the third section S3 obtained by cutting the fourth cavity 81 with a plane perpendicular to the third normal L3 passing through the center Y3 of the third opening Z3 in the normal of the tube axis X2 of the closed tube 70 (excluding the portion corresponding to the interior of the closed tube 70) is greater than the area of ​​the third opening Z3. Furthermore, the cross-sectional area of ​​at least one face within the fifth cavity 83 (particularly, further outward than the fourth opening Z4) of the fourth section S4 obtained by cutting the fifth cavity 83 with a plane perpendicular to the fourth normal L4 passing through the center Y4 of the fourth opening Z4 in the normal of the tube axis X2 of the closed tube 70 (excluding the portion corresponding to the interior of the closed tube 70) is greater than the area of ​​the fourth opening Z4. The centers Y3 and Y4 are obtained using the same method as the center Y1, and the areas of the third and fourth openings are obtained using the same method as the area of ​​the first opening.

[0054] return Figure 11 ,exist Figure 11 The left portion of the two lightly shaded sections corresponds to the area T3 of the third opening Z3, and the right portion corresponds to the area T4 of the fourth opening Z4. Additionally, in Figure 11 The left portion of the two darkly shaded sections corresponds to the cross-sectional area of ​​section S3 (section 3), and the right portion corresponds to the cross-sectional area of ​​section S4 (section 4). For example... Figure 11 As shown, the cross-sectional area of ​​the third section S3 is greater than the area T3 of the third opening Z3, and the cross-sectional area of ​​the fourth section S4 is greater than the area T4 of the fourth opening Z4.

[0055] Furthermore, regarding the shape of the fourth cavity 81, it is not particularly limited as long as the cross-sectional area of ​​the third section S3 of at least one face is greater than the area T3 of the third opening. Similarly, regarding the shape of the fifth cavity 83, it is not particularly limited as long as the cross-sectional area of ​​the fourth section S4 of at least one face is greater than the area T4 of the fourth opening. For example, the cross-sectional area of ​​all third sections S3 can be greater than the area T3 of the third opening. Alternatively, or based on this, the cross-sectional area of ​​all fourth sections S4 can be greater than the area T4 of the fourth opening. Additionally, it is also possible to... Figure 6Similarly, in the second cavity 60a shown, the cross-sectional area of ​​the third section S3 increases with distance from the third opening Z3 along the third normal L3, extending from the third opening Z3 to a position away from the third opening Z3 by a predetermined distance. Alternatively, or on this basis, the cross-sectional area of ​​the fourth section S4 increases with distance from the fourth opening Z4, extending from the fourth opening Z4 to a position away from the fourth opening Z4 along the fourth normal L4 by a predetermined distance.

[0056] The position of the third opening Z3 can correspond to the center position of the fourth cavity 81 in the tube axis direction of the closed tube 70, and the position of the fourth opening Z4 can correspond to the center position of the fifth cavity 83 in the tube axis direction of the closed tube 70. For example, Figure 12 The position of the third opening Z3 shown is set as the center position of the fourth cavity 81 in the direction of the tube axis X2, and the position of the fourth opening Z4 is set as the center position of the fifth cavity 83 in the direction of the tube axis X2.

[0057] Furthermore, similar to the case of cavity 60, the length of the closed tube 70, the area T3 of the third opening, the number of third openings Z3, the volume of the fourth cavity 81, and the cross-sectional area of ​​the third section S3, as well as the area T4 of the fourth opening, the number of fourth openings Z4, the volume of the fifth cavity 83, and the cross-sectional area of ​​the fourth section S4, are set according to the frequency (desired frequency) of the sound wave to be canceled. Additionally, cavity 81 is a space enclosed except for the third opening Z3, and has no openings other than the third opening Z3; similarly, cavity 83 is a space enclosed except for the fourth opening Z4, and has no openings other than the fourth opening Z4.

[0058] Alternatively, an exhaust pipe 20 with a closed pipe 70 can be combined with a muffler 30 with a closed pipe 50 to form an engine muffler. Furthermore, an exhaust pipe 20 with a closed pipe 70 can be combined with a conventional muffler to form an engine muffler, and a conventional exhaust pipe can be combined with a muffler 30 with a closed pipe 50 to form an engine muffler.

[0059] [The function of a noise reduction device]

[0060] use Figures 13 to 14 ,right Figure 3 The function of the second cavity 60 shown will be explained. From... Figure 13 The sound wave W, propagating from the open end 51 into the interior of the closed tube 50, propagates along the arrow from the first opening Z1 to the second cavity 60 (arrow A1), and from the first opening Z1 to the closed tube 50 (arrow A1). Due to the pressure variation of the sound wave as shown by arrow A1, it propagates into the second cavity 60, resulting in a phase delay in the waveform of the sound wave at the portion shown by B1. The sound wave reaching the closed end 52 then undergoes free-end reflection.

[0061] exist Figure 14 The sound wave reflected at the closed end 52, as shown, propagates along the arrow from the first opening Z1 to the second cavity 60 (arrow A1), and from the first opening Z1 to the closed tube 50 (arrow A1). Through this propagation of the second pressure change towards the second cavity 60, the phase of the sound wave waveform is further delayed at the portion shown by B1. The sound wave reaching the open end 51 is then output to the first cavity 31.

[0062] Next, use Figures 15 to 16 ,right Figure 12 The functions of the fourth cavity 81 and the fifth cavity 83 shown will be explained. Figure 15 In the closed tube 70, the sound wave W propagates from the open end 71 to the interior of the closed tube 70 along the arrow from the third opening Z3 to the fourth cavity 81 (arrow A2), from the fourth opening Z4 to the fifth cavity 83 (arrow A3), and reaches the closed end 72. During this period, due to the propagation of pressure changes of the sound wave to the fourth cavity 81 and to the fifth cavity 83, the phase delay of the sound wave waveform occurs at the portions shown by B2 and B3.

[0063] exist Figure 16 The sound wave reflected at the closed end 72, as shown, propagates along the arrow from the fourth opening Z4 to the fifth cavity 83 (arrow A3), and from the third opening Z3 to the fourth cavity 81 (arrow A2), and is then output from the open end 71 to the main pipe. At this time, through the propagation of pressure variations in the sound wave to the fourth cavity 81 and to the fifth cavity 83, the phase of the sound wave waveform is further delayed at the portions shown by B2 and B3. In this way, the phase delay of the sound wave waveform can be achieved while suppressing the increase in the length of the closed tubes 50 and 70.

[0064] [Embodiments of the Invention]

[0065] According to this embodiment, an engine muffler 30 is provided, which includes: a first chamber 31; and a closed tube 50, which communicates with the first chamber 31 via an open end 51 and with a second chamber 60 via a first opening Z1 on a side 53. This allows for the suppression of the enlargement of the muffler device.

[0066] In the engine muffler 30 of this embodiment, the cross-sectional area of ​​at least one surface within the second cavity 60 in the first cross-section S1 obtained by cutting the second cavity 60 with a plane perpendicular to the first normal L1 passing through the center Y1 of the first opening Z1 of the tube axis X1 of the closed tube 50 is greater than the first opening area T1 of the first opening Z1. This helps to suppress the enlargement of the muffler device.

[0067] In the engine muffler 30a of this embodiment, the closed tube 50 may have a second opening Z2 located further away from the opening end 51 than the first opening Z1. This second opening Z2 connects to a third cavity 61 having a smaller volume than the second cavity 60b. This is achieved by dividing the third cavity 61 by a plane perpendicular to the second normal L2 passing through the center Y2 of the second opening Z2, and the cross-sectional area of ​​at least one surface within the third cavity 61 is greater than the area T2 of the second opening Z2. This further suppresses the enlargement of the muffler device.

[0068] In the engine muffler 30a of this embodiment, the third chamber 61 may have a connecting pipe 37 that directly connects multiple different chambers adjacent to the third chamber 61 to each other. This allows for efficient utilization of the internal space of the muffler 30a.

[0069] In the engine muffler 30a of this embodiment, the position of the first opening Z1 may correspond to the center position of the second cavity 60b in the tube axis direction of the closed tube 50, and the position of the second opening Z2 may correspond to the center position of the third cavity 61 in the tube axis direction. This can suppress resonance generated inside the second cavity 60b and the third cavity 61.

[0070] In the engine muffler 30a of this embodiment, it may also have a frame 32 having the first cavity, the second cavity, and the third cavity. The third cavity 61 is located opposite to the center of the frame 32 in the tube axis direction relative to the second cavity 60b. This can suppress the concentration of thermal stress on a portion of the frame 32.

[0071] In the engine muffler 30a of this embodiment, a tailpipe 40 may be included to discharge exhaust gas from the engine 10 to the outside. The tailpipe 40 has an inner end 41 located in the first chambers 31a, 31b, and 31c and communicating with the open end 51. The open end 51 is positioned closer to the inner end 41 than the end of any pipe other than the closed pipe 50. This effectively cancels out exhaust noise before it is discharged from the muffler 30a.

[0072] In the engine muffler 30a of this embodiment, it may also have a frame 32 and partitions 33 to 36 that divide the interior of the frame 32, wherein the first chambers 31a, 31b, 31c and the second chamber 60b are formed by the frame 32 and the partitions 33 to 36. This allows for miniaturization of the muffler device.

[0073] In the engine muffler 30 of this embodiment, the cross-sectional area of ​​all the first sections S1 may be larger than the area T1 of the first opening. This promotes the introduction of sound waves into the second cavity 60 (propagation of sound wave pressure changes).

[0074] In the engine muffler 30 of this embodiment, the cross-sectional area of ​​the first section S1 may increase as it moves away from the first opening Z1 within a range R from the first opening Z1 to a position along the first normal L1 that is a predetermined distance away from the first opening Z1. This promotes the introduction of sound waves into the second cavity 60.

[0075] Furthermore, according to this embodiment, an engine exhaust pipe 20 is provided, which includes: a main pipe; and a closed pipe 70, which communicates with the main pipe via an open end 71 and with a fourth chamber 81 via a third opening Z3 on the side 73. This allows for the suppression of the enlargement of mufflers.

[0076] In the engine exhaust pipe 20 of this embodiment, the cross-sectional area of ​​at least one surface within the fourth cavity 81 in the third cross-section S3 obtained by cutting the fourth cavity 81 with a plane perpendicular to the third normal L3 passing through the center Y3 of the third opening Z3 in the normal to the pipe axis X2 of the closed pipe 70 is greater than the area T3 of the third opening Z3. This allows for the suppression of the need for larger mufflers.

[0077] In the engine exhaust pipe 20 of this embodiment, the closed pipe 70 may have a fourth opening Z4 located further away from the opening end 71 than the third opening Z3. Through the fourth opening Z4, it communicates with a fifth cavity 83 having a smaller volume than the fourth cavity 81. This is achieved by dividing the fifth cavity 83 by a plane perpendicular to the fourth normal L4 passing through the center Y4 of the fourth opening Z4, and the cross-sectional area of ​​at least one surface within the fifth cavity 83 is greater than the fourth opening area T4 of the fourth opening Z4. This further suppresses the enlargement of the muffler.

[0078] In the engine exhaust pipe 20 of this embodiment, the position of the third opening Z3 may correspond to the center position of the fourth cavity 81 in the pipe axis direction of the closed pipe 70, and the position of the fourth opening Z4 may correspond to the center position of the fifth cavity 83 in the pipe axis direction. This can suppress resonance generated inside the fourth cavity 81 and the fifth cavity 83.

[0079] In the engine exhaust pipe 20 of this embodiment, the cross-sectional area of ​​all the third sections S3 may be larger than the area of ​​the third opening T3. This promotes the introduction of sound waves into the fourth cavity 81 (propagation of sound wave pressure changes).

[0080] In the engine exhaust pipe 20 of this embodiment, the cross-sectional area of ​​the third section S3 may increase as it moves away from the third opening Z3, from the third opening Z3 to a position along the third normal L3 at a predetermined distance. This promotes the introduction of sound waves into the fourth cavity 81 (propagation of sound wave pressure variations).

[0081] According to this embodiment, the second cavities 60, 60a, and 60b can be enclosed spaces except for the first opening Z1, the third cavity 61 can be enclosed spaces except for the second opening Z2, the fourth cavity 81 can be enclosed spaces except for the third opening Z3, and the fifth cavity 83 can be enclosed spaces except for the fourth opening Z4. This allows pressure to accumulate inside the cavities.

[0082] Explanation of the label

[0083] 10… Engine

[0084] 20…exhaust pipe

[0085] 30, 30a…silencers; 31, 31a, 31b, 31c…first chamber; 32…frame; 33, 34, 35, 36…partitions; 37, 38…connecting pipes

[0086] 40…tailpipe, 41…inner end, 42…outer end

[0087] 50…closed end, 51…open end, 52…closed end, 53…side

[0088] 60, 60a, 60b… Second cavity

[0089] 61… Third cavity

[0090] 70…closed end, 71…open end, 72…closed end, 73…sideways

[0091] 80, 82… cavities, 81… 4th cavity, 83… 5th cavity

[0092] Arrows A1, A2, A3…

[0093] B1, B2, B3… (partial)

[0094] E1, E2... End faces

[0095] F1, F2, F3, F4, F5, F6… arrows

[0096] P…projection surface

[0097] Q…location

[0098] R…range

[0099] L1…1st normal, L2…2nd normal, L3…3rd normal, L4…4th normal

[0100] S1, S1a… Section 1, S2… Section 2, S3… Section 3, S4… Section 4

[0101] T1…area of ​​the first opening, T2…area of ​​the second opening, T3…area of ​​the third opening, T4…area of ​​the fourth opening

[0102] W…sound wave

[0103] X1, X2... Tube shaft

[0104] Y1, Y2, Y3, Y4… Center

[0105] Z1…first opening, Z2…second opening, Z3…third opening, Z4…fourth opening.

Claims

1. An engine muffler, comprising: First cavity; and The tube is closed, and it communicates with the first cavity via the open end and with the second cavity via the first opening on the side.

2. The engine muffler according to claim 1, wherein, The cross-sectional area of ​​at least one surface within the second cavity in the first cross-section obtained by cutting the second cavity with a plane perpendicular to the first normal passing through the center of the first opening in the tube axis of the closed tube is greater than the area of ​​the first opening of the first opening.

3. The engine muffler according to claim 2, wherein, The closed tube has a second opening located further away from the first opening than the first opening, and communicates via the second opening with a third cavity having a smaller volume than the second cavity. The cross-sectional area of ​​at least one surface within the third cavity in the second cross-section obtained by cutting the third cavity with a plane perpendicular to the second normal passing through the center of the second opening is greater than the area of ​​the second opening.

4. The engine muffler according to claim 3, wherein, The third cavity has a connecting tube that directly connects multiple different cavities adjacent to the third cavity to each other.

5. The engine muffler according to claim 3 or 4, wherein, The position of the first opening corresponds to the position of the center of the second cavity in the axial direction of the closed tube. The position of the second opening corresponds to the position of the center of the third cavity in the direction of the tube axis.

6. The engine muffler according to any one of claims 3 to 5, wherein, It has a frame, which has the first cavity, the second cavity, and the third cavity. The third cavity is located on the opposite side of the second cavity, relative to the center of the frame in the direction of the tube axis of the closed tube.

7. The engine muffler according to any one of claims 1 to 6, wherein, It has a tailpipe that vents engine exhaust gases to the outside. The tail tube has an internal end located in the first cavity and communicating with the open end. The position of the open end is a position that communicates with the inner end and is closer to the inner end than the end of the tube other than the closed tube.

8. The engine muffler according to any one of claims 1 to 7, wherein, It has a frame and partitions that divide the interior of the frame. The first cavity and the second cavity are formed by the frame and the partition.

9. The engine muffler according to any one of claims 2 to 6, wherein, The cross-sectional area of ​​all the first sections is greater than the area of ​​the first opening.

10. The engine muffler according to any one of claims 2 to 6, wherein, The cross-sectional area of ​​the first profile increases as it moves away from the first opening, from the first opening to a position along the first normal that is a predetermined distance away from the first opening.

11. An exhaust pipe for an engine, comprising: Supervisor; and The closed tube is connected to the main tube via the open end and to the fourth cavity via the third opening on the side.

12. The exhaust pipe for an engine according to claim 11, wherein, The cross-sectional area of ​​at least one surface within the fourth cavity in the third cross-section obtained by cutting the fourth cavity with a plane perpendicular to the third normal passing through the center of the third opening in the normal of the tube axis of the closed tube is greater than the area of ​​the third opening of the third opening.

13. The exhaust pipe for an engine according to claim 12, wherein, The closed tube has a fourth opening located further away from the opening end than the third opening, and communicates via the fourth opening with a fifth cavity having a smaller volume than the fourth cavity. The cross-sectional area of ​​at least one surface within the fifth cavity in the fourth section obtained by cutting the fifth cavity with a plane perpendicular to the fourth normal passing through the center of the fourth opening is greater than the area of ​​the fourth opening.

14. The exhaust pipe for an engine according to claim 13, wherein, The position of the third opening corresponds to the position of the center of the fourth cavity in the axial direction of the closed tube. The position of the fourth opening corresponds to the position of the center of the fifth cavity in the direction of the tube axis.

15. An exhaust pipe for an engine according to any one of claims 12 to 14, wherein, The cross-sectional area of ​​all the third sections is greater than the area of ​​the third opening.

16. The exhaust pipe for an engine according to any one of claims 12 to 15, wherein, The cross-sectional area of ​​the third section increases as it moves away from the third opening, from the third opening to a position along the third normal that is a predetermined distance away from the third opening.

17. The engine muffler according to any one of claims 1 to 10, wherein, The second cavity is a closed space except for the first opening.

18. The engine muffler according to any one of claims 3 to 6, wherein, The third cavity is a closed space except for the second opening.

19. An exhaust pipe for an engine according to any one of claims 11 to 16, wherein, The fourth cavity is a closed space except for the third opening.

20. The exhaust pipe for an engine according to claim 13 or 14, wherein, The fifth cavity is a closed space except for the fourth opening.

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