WO2012090238A1 - Dispositif d'échappement - Google Patents

Dispositif d'échappement Download PDF

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Publication number
WO2012090238A1
WO2012090238A1 PCT/JP2010/007538 JP2010007538W WO2012090238A1 WO 2012090238 A1 WO2012090238 A1 WO 2012090238A1 JP 2010007538 W JP2010007538 W JP 2010007538W WO 2012090238 A1 WO2012090238 A1 WO 2012090238A1
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WO
WIPO (PCT)
Prior art keywords
exhaust
passage
pipe
exhaust gas
opening end
Prior art date
Application number
PCT/JP2010/007538
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English (en)
Japanese (ja)
Inventor
仲矢 高垣
Original Assignee
トヨタ自動車株式会社
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Publication date
Application filed by トヨタ自動車株式会社 filed Critical トヨタ自動車株式会社
Priority to PCT/JP2010/007538 priority Critical patent/WO2012090238A1/fr
Publication of WO2012090238A1 publication Critical patent/WO2012090238A1/fr

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N1/00—Silencing apparatus characterised by method of silencing
    • F01N1/16—Silencing apparatus characterised by method of silencing by using movable parts
    • F01N1/165—Silencing apparatus characterised by method of silencing by using movable parts for adjusting flow area
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N1/00—Silencing apparatus characterised by method of silencing
    • F01N1/02—Silencing apparatus characterised by method of silencing by using resonance
    • F01N1/026—Annular resonance chambers arranged concentrically to an exhaust passage and communicating with it, e.g. via at least one opening in the exhaust passage
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N1/00—Silencing apparatus characterised by method of silencing
    • F01N1/08—Silencing apparatus characterised by method of silencing by reducing exhaust energy by throttling or whirling
    • F01N1/083—Silencing apparatus characterised by method of silencing by reducing exhaust energy by throttling or whirling using transversal baffles defining a tortuous path for the gases or successively throttling gas flow
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2470/00—Structure or shape of gas passages, pipes or tubes
    • F01N2470/02—Tubes being perforated

Definitions

  • the present invention relates to an exhaust device, and more particularly to an exhaust device that suppresses an increase in the particle velocity of exhaust sound due to air column resonance occurring in an exhaust pipe of an internal combustion engine.
  • an exhaust device 1 as shown in the upper part of FIG. 17 is known as this type of exhaust device.
  • the exhaust device 1 includes a front pipe 3 connected to the engine 2 and a catalytic converter 4 including catalytic converters 4 a and 4 b provided on the front pipe 3.
  • the exhaust device 1 includes a tail pipe 5 connected to the catalytic converter 4 b, a sub muffler 6 provided on the tail pipe 5, and a main muffler 7 connected to the tail pipe 5.
  • the sub muffler 6 has an exhaust gas passage 8a that communicates with the exhaust gas passage 5a of the tail pipe 5, and a sub pipe 8 that is connected to the tail pipe 5, and a resonance chamber 6a that communicates with the exhaust gas passage 8a. And. As shown in the upper part of FIG. 17, the sub muffler 6 is disposed in the center portion of the tail pipe 5.
  • the antinode portion of the sound pressure level of the standing wave indicated by the arrow a in the sound pressure mode of the air column resonance generated in the tail pipe 5 is reduced by the Helmholtz resonance action of the resonance chamber 6a. It has become.
  • the sound pressure mode in the tail pipe 5 since both ends of the tail pipe 5 are open ends, as shown in the center part of FIG. 17, the sound pressure is lowest at both ends and the sound pressure is highest at the center part. Sound pressure mode of air column resonance.
  • the particle velocity indicated by the solid line it is opposite to the sound pressure mode, and the particle velocity is highest at both ends and lowest at the center.
  • the main muffler 7 includes a main body 7a, an inlet pipe portion 5A of the tail pipe 5 inserted into the main body 7a, and an outlet pipe 7b.
  • the main body 7a has an expansion chamber 7A and a resonance chamber 7B adjacent to the expansion chamber 7A.
  • the inlet pipe portion 5A passes through the expansion chamber 7A and the resonance chamber 7B and opens at the resonance chamber 7B.
  • a plurality of small holes 5b are formed in the wall portion of the inlet pipe portion 5A located in the expansion chamber 7A, and the exhaust gas passage 5c in the inlet pipe portion 5A communicates with the expansion chamber 7A.
  • the outlet pipe 7b opens in the expansion chamber 7A and extends so as to penetrate the resonance chamber 7B and is opened in the atmosphere.
  • the resonance chamber 7B is generated between a connection portion 3a of the front pipe 3 with the engine 2 and an opening portion 7d on the atmosphere side of the outlet pipe 7b as shown in the lower part of FIG.
  • the sound pressure level in the air column resonance mode of the exhaust system is reduced by the so-called Helmholtz resonance action.
  • the connection portion 3a of the front pipe 3 to the engine 2 is closed by an unillustrated exhaust valve, and the opening portion 7d is an opening end.
  • a sound pressure mode of air column resonance in which the sound pressure is lowest at the opening portion 7d and the middle portion of the exhaust system, and the sound pressure is highest at the central portion between the connecting portion 3a and the middle portion having the lowest sound pressure and the opening portion 7d. It has become.
  • the sound pressure mode is reversed, the particle velocity is highest in the opening portion 7d and the middle portion of the exhaust system, and the middle of the connecting portion 3a and the middle portion having the highest particle velocity and the opening portion 7d. Particle velocity is lowest in the part.
  • the sound pressure level of the specific frequency generated in the tail pipe 5 is reduced by the sub muffler 6, and the sound pressure level of the specific frequency generated in the exhaust system is reduced by the resonance chamber 7B. That is, the sound pressure level in a wide frequency band other than the two specific frequencies is reduced.
  • the cooperation of the sub muffler 6 and the main muffler 7 provided on the tail pipe 5 as described above causes the specific frequency of the different specific frequencies due to the air column resonance generated in the tail pipe 5 and the exhaust system.
  • the mode of air column resonance is reduced by Helmholtz resonance.
  • the flow rate of the exhaust gas flowing through the sub muffler 6 and the main muffler 7 is small when the engine is decelerated or rotated at a low speed. Further, there is a problem that the Helmholtz resonance action in the resonance chamber 7B of the main muffler 7 does not work effectively. For this reason, particularly when the engine is decelerated or when the engine is running at a low speed, the noise due to the exhaust noise is not sufficiently reduced, and the reduction of the booming noise generated in the passenger compartment is insufficient.
  • a silencer valve that opens and closes the exhaust pipe is provided, and the opening and closing of the silencer valve is controlled to suppress noise generation due to air column resonance.
  • An exhaust device configured to do this is known (for example, see Patent Document 1).
  • a silencer valve is provided at the downstream opening end of the tail pipe, which is a node of the sound pressure of the standing wave of air column resonance, and this silencer valve is attached to the downstream opening end of the tail pipe. It consists of a valve case and a butterfly valve type valve body, and an orifice for restricting the passage cross-sectional area of the tail pipe is formed at the center of the valve body.
  • valve body is provided with a drive shaft, and this drive shaft is provided so as to extend in a direction orthogonal to the central axis in the extending direction of the tail pipe.
  • the drive shaft is connected to an electromagnetic actuator via a drum and a wire, and the electromagnetic actuator is controlled to be turned on / off by a control unit.
  • the control unit outputs a command signal for controlling the electromagnetic actuator to the electromagnetic actuator based on a detection signal of a throttle sensor that detects the opening of the throttle valve.
  • the control unit outputs an off signal to the electromagnetic actuator to keep the valve body open by the electromagnetic actuator.
  • the control unit outputs an ON signal to the electromagnetic actuator based on detection information from the throttle sensor when the vehicle is decelerated, and causes the valve body to be closed by the electromagnetic actuator.
  • the present invention has been made to solve the above-described conventional problems, and eliminates the need for installing a sub-muffler in the tail pipe and an opening / closing mechanism for an exhaust passage in the main muffler, and has a simple structure. It is an object of the present invention to provide an exhaust device capable of reducing the particle velocity of exhaust sound having a specific frequency due to air column resonance generated in the exhaust system, and reducing the weight and manufacturing cost.
  • an exhaust system is configured to allow the exhaust gas to flow from an introduction opening end that introduces exhaust gas of an internal combustion engine toward an exhaust opening end that exhausts the exhaust gas into the atmosphere.
  • the exhaust device having an exhaust pipe having the exhaust pipe, wherein the exhaust passage is partitioned into a large passage having a large passage cross-sectional area and a small passage having a small passage cross-sectional area in a predetermined section along the flow direction of the exhaust gas.
  • the exhaust device eliminates the need for installing a sub-muffler in the tail pipe and installing an opening / closing mechanism for the exhaust passage in the main muffler, and by air column resonance generated in the exhaust system with a simple structure.
  • the particle speed of the exhaust sound of a specific frequency is reduced, and the weight and manufacturing cost are reduced.
  • valve body When the rotational speed of the internal combustion engine is relatively low, the valve body is in a closed state, and the exhaust gas is exhausted into the atmosphere through the small passage. The particle velocity is suppressed in the small passage. As a result, an increase in air column resonance excited in the exhaust pipe is suppressed.
  • the small passage is formed in a predetermined section along the exhaust direction, the allowable range of the dimensional accuracy of the height of the small passage can be made relatively large, and the number of processing steps and assembly steps of the components are reduced. In addition, the yield of producing good products is increased. As a result, the manufacturing cost is reduced.
  • the conventional exhaust system has a structure in which there is no passage corresponding to a small passage, and an opening having a small cross-sectional area is simply formed.
  • an opening having a small cross-sectional area is simply formed.
  • it is necessary to reduce the height of the small opening to about several millimeters and to form it with high accuracy.
  • the exhaust device according to the present invention since the small passage is formed in a predetermined section along the exhaust direction, the necessity of forming with such high accuracy is eliminated.
  • the valve body When the rotational speed of the internal combustion engine is relatively high, the valve body is opened by the flow of exhaust gas, and the exhaust gas flows into the large passage through the communication hole and is exhausted into the atmosphere from the exhaust opening end. The As a result, the back pressure of the exhaust gas does not increase and the load on the internal combustion engine does not increase.
  • the exhaust system according to the present invention has a sound pressure of the exhaust sound of the primary component and the secondary component having different specific frequencies due to the air column resonance generated in the exhaust system and the exhaust pipe which are particularly problematic in comparison with the conventional exhaust system. And reduced.
  • the problem of noise such as a booming noise generated in the vehicle interior due to air column resonance of the exhaust device is solved. Since a control device and a sub-muffler for controlling a mechanism for reducing the sound pressure at the specific frequency are not required, the weight and manufacturing cost are reduced.
  • the exhaust device according to the present invention is preferably configured such that the partition member is provided in the exhaust pipe so that the exhaust direction downstream side of the section becomes the exhaust opening end.
  • the partition member is provided in the exhaust pipe so that the downstream side in the exhaust direction of the section is the exhaust opening end, so that the particles in the standing wave of air column resonance excited in the exhaust pipe This particle velocity can be reduced in the largest velocity range.
  • the length of the section in the flow direction of the exhaust gas is a downstream side that opens from an upstream opening end that opens to the upstream side of the exhaust pipe to a downstream side of the exhaust pipe.
  • the length is approximately 1/4 of the length to the opening end.
  • the exhaust apparatus according to the present invention has an exhaust opening end on the downstream side in the exhaust direction of the section and an exhaust opening from an upstream opening end in which the length of the exhaust gas in the section opens on the upstream side of the exhaust pipe. Since it is formed with approximately 1 ⁇ 4 of the length to the downstream opening end that opens to the downstream side of the tube, this particle has the largest particle velocity in the standing wave of air column resonance excited in the exhaust pipe. Speed can be reduced.
  • the exhaust device preferably includes a pressing member that presses the valve body against the communication member so as to close the communication hole when the flow rate of the exhaust gas flowing through the exhaust passage is relatively small. To do.
  • the valve body presses the communication member by the pressing member, the communication hole of the connection member is reliably closed by the valve body.
  • the communication hole is stably closed without being affected by the environment such as vibration of surrounding components.
  • the present invention it is not necessary to install a sub-muffler in the tail pipe or an exhaust passage opening / closing mechanism in the main muffler, and an exhaust sound of a specific frequency due to air column resonance generated in the exhaust system with a simple structure. It is possible to provide an exhaust device that can reduce the particle velocity and reduce the weight and manufacturing cost.
  • FIG. 4 is a view showing an embodiment of an exhaust device according to the present invention, and is a cross-sectional view of a muffler showing a cross section AA of FIG. 3.
  • FIG. 8 is a view showing an embodiment of the exhaust device according to the present invention, and is a cross-sectional view of the outlet pipe showing a BB cross section of FIG. 7.
  • FIG. 1 It is a figure which shows the exhaust system provided with the conventional exhaust apparatus
  • the upper part of a figure is a longitudinal cross-sectional view of the muffler which connected the sub muffler and the tail pipe, and the outlet pipe, and the center part of a figure generate
  • the mode of air column resonance is shown, and the lower part of the figure shows the mode of air column resonance generated in the exhaust system from the closed end of the front pipe to the open end of the outlet pipe.
  • FIG. 1 to 15 are views showing an embodiment of an exhaust device according to the present invention, and the configuration of the exhaust device 20 according to the embodiment will be described with reference to the drawings.
  • the exhaust device 20 is connected to an engine 10 as an in-line four-cylinder internal combustion engine, and is configured to purify exhaust gas discharged from the engine 10 and discharge it to the atmosphere. Has been.
  • the exhaust device 20 further reduces the particle velocity of standing waves in the air column resonance generated inside. That is, the increase in the sound pressure of the exhaust sound generated by the air column resonance is suppressed.
  • the engine 10 includes an engine main body 11 serving as a drive source for the vehicle, and an exhaust manifold 12 that distributes exhaust gas discharged from the engine main body 11.
  • the engine 10 is not limited to the in-line 4 cylinders, and may be configured by in-line 3 cylinders or in-line 5 cylinders or more, and is configured by a V-type engine having 3 or more cylinders in each bank divided into left and right. May be.
  • the exhaust manifold 12 includes four exhaust branch pipes 12a, 12b, 12c, and 12d connected to exhaust ports communicating with the first to fourth cylinders of the engine body 11, and exhaust branch pipes 12a, 12b, 12c,
  • the exhaust collecting pipe 12e collects the downstream side of 12d.
  • the exhaust gas exhausted from each cylinder of the engine 10 is introduced into the exhaust collecting pipe 12e through the exhaust branch pipes 12a, 12b, 12c, and 12d.
  • the exhaust device 20 includes a catalytic converter 21 including catalytic converters 21a and 21b, a front pipe 23 connected to the catalytic converter 21a via a universal joint 22, and an exhaust pipe connected to the catalytic converter 21b via a universal joint 24.
  • the tail pipe 25 and a muffler 30 as a silencer connected to the tail pipe 25 are provided.
  • the exhaust device 20 is installed on the downstream side of the engine 10 so as to be elastically suspended below the floor of the vehicle.
  • the upstream side indicates the upstream side in the exhaust direction of the exhaust gas discharged from the engine 10, and the downstream side indicates the downstream side in the exhaust direction of the exhaust gas.
  • the catalytic converters 21a and 21b are each formed by attaching a catalyst such as platinum or palladium to a honeycomb base material or a granular activated alumina support, and have a main body case for storing them.
  • the catalytic converter 21a connected to the downstream end of the exhaust collecting pipe 12e at the upstream end and the catalytic converter 21b connected to the tail pipe 25 at the downstream end respectively reduce NOx in the exhaust gas exhausted from the exhaust collecting pipe 12e. And CO and HC are oxidized.
  • the universal joint 22 is composed of a spherical joint such as a ball joint, and allows relative displacement between the catalytic converter 21 a and the front pipe 23.
  • the universal joint 24 is formed of a spherical joint such as a ball joint, and allows relative displacement between the catalytic converter 21 b and the tail pipe 25.
  • the front pipe 23 is formed in a cylindrical shape, and has an exhaust passage 23b through which exhaust gas discharged from the catalytic converter 21a is introduced from the introduction opening end 23a and flows to the catalytic converter 21b.
  • the tail pipe 25 is also formed in a cylindrical shape like the front pipe 23, and has an upstream opening end through which exhaust gas discharged from the exhaust passage 25a and the catalytic converter 21b flows into the exhaust passage 25a. 25b and the downstream opening end 25c which discharges
  • the downstream opening end 25 c is formed in the inlet pipe portion 25 ⁇ / b> A of the tail pipe 25 inserted into the muffler 30.
  • the muffler 30 includes a muffler body 31, a separator 32, an inlet pipe portion 25A constituting a part of the tail pipe 25, and an outlet pipe 33 as an exhaust pipe.
  • the exhaust gas flowing into the muffler main body 31 from the inlet pipe portion 25A is discharged from the outlet pipe 33, and the exhaust sound is muted in the muffler main body 31.
  • the muffler body 31 includes an outer shell 41 formed in a cylindrical shape, an end plate 42 that closes both ends of the outer shell 41 to define an internal space, and an end plate 43.
  • the end plates 42 and 43 are respectively fixed to the outer shell 41 by fixing means such as caulking so that the exhaust gas does not leak from the internal space to the outside.
  • a separator 32 is interposed between the end plate 42 and the end plate 43.
  • the separator 32 partitions the internal space in the muffler main body 31 into an expansion chamber 30A located on the upstream side in the exhaust direction and a resonance chamber 30B located on the downstream side in the exhaust direction of the expansion chamber 30A.
  • the end plate 42 is formed with an insertion hole 42a, and the separator 32 is formed with insertion holes 32a and 32b.
  • An inlet pipe portion 25A is inserted through these insertion holes 42a and 32a.
  • through holes 43a are formed in the end plate 43, and the outlet pipe 33 is inserted through these through holes 32b and 43a.
  • the inlet pipe portion 25A has a plurality of communication holes 25d that allow the exhaust passage 25a and the expansion chamber 30A to communicate with each other. Exhaust gas flows into the expansion chamber 30A from the communication hole 25d. Further, exhaust gas flows from the downstream opening end 25c of the inlet pipe portion 25A into the resonance chamber 30B.
  • the expansion chamber generally has a relatively large cross-sectional area (mm 2) with respect to the cross-sectional area of the exhaust passage in the inlet pipe in the muffler (mm 2), provided with a predetermined volume (mm 3) It consists of hollows.
  • mm 2 cross-sectional area
  • mm 3 predetermined volume
  • the expansion chamber when the exhaust gas flows into the expansion chamber from the exhaust passage, the volume of the exhaust gas is rapidly expanded, the pressure fluctuation due to the exhaust pulsation is weakened, and the sound pressure level (dB) of the exhaust sound is reduced.
  • the so-called expansion effect is obtained in which the frequency is reduced over a wide frequency band.
  • the resonance chamber is a cavity having a predetermined volume (mm 3 ) so as to resonate an exhaust sound having a specific frequency (Hz) using the so-called Helmholtz resonance principle.
  • the resonance chamber is connected to a resonance pipe p having a so-called neck portion having an introduction passage b, and is formed in the resonance member so as to communicate with the introduction passage b.
  • the exhaust sound of a specific frequency resonates.
  • the specific frequency is f (Hz)
  • the sectional area of the resonance pipe p is S (mm 2 )
  • the length of the resonance pipe p that is, the distance of the introduction passage b is L (mm)
  • the volume of the cavity h is V ( mm 3 )
  • c is the speed of sound in air (m / s)
  • the specific frequency f is known to be represented by the following formula (1).
  • the frequency (Hz) of the exhaust sound propagating from the introduction passage b to the cavity h coincides with f
  • the exhaust sound resonates in the cavity h.
  • air vibrates vigorously in the branch passage b of the resonance pipe p and vibration energy is converted into heat energy and attenuated due to friction with the inner wall of the resonance pipe p.
  • the resonant exhaust noise is reduced.
  • the specific frequency f is a frequency that substantially matches the frequency of the air column resonance that occurs in the exhaust system of the embodiment when the engine speed Ne (rpm) is relatively low, and in the exhaust system mode shown in the lower part of FIG.
  • the sound pressure of the air column resonance is set to be reduced by Helmholtz resonance in the muffler 30.
  • the outlet pipe 33 includes a circular pipe portion 51 having a circular outer periphery and a square pipe portion 52 having a rectangular outer periphery.
  • the circular pipe portion 51 is configured by a circular pipe connected to the square pipe portion 52.
  • the circular pipe portion 51 includes an expansion chamber opening end 51a that opens in the expansion chamber 30A, a communication opening end 51b that opens to communicate with the rectangular pipe portion 52, and an expansion chamber opening end 51a and a communication opening end 51b. And an exhaust passage 51c through which the exhaust gas flows.
  • the rectangular pipe portion 52 includes a rectangular pipe main body 61, a partition member 62, a communication member 63, a swing shaft 64, and a valve body 65.
  • the square pipe body 61 has a connection end 61a as an upstream opening end connected to the circular pipe portion 51 and an atmosphere opening end 61b that opens to the atmosphere as an exhaust opening end, and the connection end 61a and the atmosphere opening end 61b. And an exhaust passage 61c through which the exhaust gas flows.
  • the connecting end 61 a has a wall portion 61 d and a through hole 61 e formed so as to penetrate the wall portion 61 d, and the exhaust gas in the exhaust passage 51 c penetrates from the communication opening end 51 b of the circular pipe portion 51. It flows into the exhaust passage 61c through the hole 61e.
  • the partition member 62 is formed of a plate material, and is attached to the inside of the rectangular pipe body 61 so as to partition the exhaust passage 61c into a large passage 61f having a large passage sectional area and a small passage 61g having a small passage sectional area.
  • This length La is 8 of the wavelength ⁇ of the standing wave when a standing wave due to air column resonance is formed in the outlet pipe 33. In this region, the particle velocity is high. For this reason, it is more preferable that the small passage described above is provided in the region indicated by the length La so that the particle velocity can be reduced.
  • a curve indicated by a substantially parabolic curve a represents the magnitude of the particle velocity in the standing wave of the air column resonance of the exhaust pipe whose both ends are open ends.
  • the particle velocity is a minimum of zero and maximum at both ends.
  • the direction of the white arrow represents the direction of particle velocity, and represents that open end reflection occurs at the open ends of both ends.
  • the incident wave G is the air opening end 61b of the small passage 61g of the outlet pipe 33, both the transmitted wave G 1 is being transmitted to the air, the expansion chamber opening end 51a from the atmosphere opening end 61b A reflected wave R 1 (open end reflected wave) indicated by a solid line is reflected. Further, the incident wave G is towards the expansion chamber opening end 51a in the valve body 65 in the closed position reflected waves indicated by a broken line (closed end reflection wave) R 2 is reflected.
  • the reflected wave R 1 is an open end reflected wave having the same phase as the incident wave G, and the reflected wave R 2 is a closed end reflected wave having a phase difference of 180 degrees with respect to the incident wave G.
  • the reflected wave R 1 has the same phase as the incident wave G, and therefore the incident wave G and the reflected wave R 1 overlap.
  • the reflected wave R 1 is changed to the incident wave G.
  • the reflected wave R 2 corresponding to this is also drawn with the horizontal line of phase 0 as the center.
  • the reflected wave R 1 is in phase with the incident wave G, when the frequency of the incident wave G becomes the air column resonance frequency of the outlet pipe 33, mutual interference occurs between the incident wave G and the reflected wave R 1.
  • the sound pressure level of the exhaust sound is increased.
  • the reflected wave R 2 is 180 degrees out of phase with the reflected wave R 1 and the incident wave G, they cancel each other and the sound pressure level of the exhaust sound is reduced.
  • the frequency of the incident wave G due to the exhaust pulsation becomes the primary component f 1 of the air column resonance frequency of the outlet pipe 33
  • the interference due to the reflected wave R 1 that is the open end reflected wave alone is As indicated by the broken line, the sound pressure level increases (becomes maximal).
  • due to the presence of interference due to the reflected wave R 2 is a closed end reflected wave, as shown by the solid line, increase in the sound pressure level due to air column resonance is suppressed, greatly sound pressure level of exhaust sound Reduced to
  • the frequency of the incident wave G due to the exhaust pulsation becomes the secondary component f 2 of the air column resonance frequency of the outlet pipe 33
  • the small passage 61g at the atmospheric opening end 61b is made considerably smaller than the opening area of the exhaust passage 61c, for example, by 1/3 or less, the sound pressure level due to air column resonance is most suppressed.
  • FIG. 8 has a small passage 61g of the length of the length L 1 of the section along the flow direction of exhaust gas, as described above, the length L 1, the exhaust passage 61c of the outlet pipe 33 In the region where the particle velocity of the standing wave of the air column resonance generated in the region is almost the same as the length La shown in FIG. 9, the particle velocity is suppressed in the section of the region where the particle velocity is high. Become.
  • the communication member 63 is formed of a plate material, and is attached to the inside of the rectangular pipe main body 61 so as to be located upstream of the partition member 62 in the exhaust direction.
  • the communication member 63 includes a communication hole 63a that connects the large passage 61f and the exhaust passage 51c, and the exhaust gas in the exhaust passage 61c flows into the large passage 61f through the communication hole 63a. It has become.
  • the rocking shaft 64 is made of a cylindrical bar and has one end 64a and the other end 64b.
  • the one end portion 64 a and the other end portion 64 b are directly attached to a wall portion 61 h adjacent to the communication member 63 of the rectangular pipe body 61 so as to be swingable.
  • the valve body 65 is formed of a plate material and includes a main body 65a and a swinging portion 65b.
  • the main body 65 a is formed in a size that can close the communication hole 63 a of the communication member 63.
  • the oscillating portion 65 b is attached to the oscillating shaft 64.
  • the swinging portion 65 b may be supported by the swinging shaft 64 so as to swing freely, or may be fixed to the swinging shaft 64.
  • the valve body 65 is configured to vary the flow rate of the exhaust gas flowing through the communication hole 63a by receiving only the exhaust flow flowing through the exhaust passage 61c. When the exhaust gas does not flow in the exhaust passage 61c and when the flow rate of the exhaust gas is small, the valve body 65 is in a state of closing the communication hole 63a.
  • the valve body 65 is configured such that the degree of opening increases as the flow rate of the exhaust gas in the exhaust passage 61c increases, and the amount of exhaust gas passing through the communication hole 63a increases as the degree of opening increases. .
  • the exhaust system described above includes the exhaust manifold 12, the catalytic converter 21a, the front pipe 23, the catalytic converter 21b, the tail pipe 25, the muffler 30, the outlet from the position of the closed exhaust valve in the engine 10 shown in FIG. This refers to the entire path of exhaust gas flowing through the pipe 33.
  • the air column resonance generated in the exhaust system is excited between the closed end of the closed exhaust valve and the atmospheric opening end 61b of the square pipe portion 52 of the outlet pipe 33 that opens to the atmosphere, and the mode shown in the lower part of FIG. It becomes.
  • the exhaust gas exhausted from each cylinder of the engine 10 is introduced from the exhaust manifold 12 to the catalytic converter 21, and the catalytic converter 21 performs NOx.
  • Exhaust gas purification such as reduction of CO and oxidation of CO and HC is performed.
  • the purified exhaust gas is introduced into the inlet pipe portion 25A through the tail pipe 25.
  • the exhaust gas in the expansion chamber 30A is exhausted from the expansion chamber opening end 51a of the outlet pipe 33 through the exhaust passage 51c to the atmosphere from the atmosphere opening end 61b.
  • the exhaust gas in the exhaust passage 25a flows into the resonance chamber 30B from the downstream opening end 25c.
  • Helmholtz resonance is excited in the resonance chamber 30B, and the sound pressure of air column resonance generated in the exhaust system is reduced.
  • valve body 65 When the engine rotational speed Ne (rpm) is relatively low, as shown in FIG. 13, the valve body 65 is closed by its own weight, and the exhaust gas flowing through the exhaust passage 51c flows from the inlet 62a. It flows into the small passage 61g and is exhausted into the atmosphere from the outlet 62b.
  • the incident wave of the exhaust sound propagating in the exhaust passage 51c is reflected at the closed end by the valve body 65 in the closed state, and proceeds in the upstream direction of the exhaust gas. Simultaneously with this closed end reflection, the incident wave of the exhaust sound is reflected at the opening end at the inlet 62a of the small passage 61g and proceeds in the upstream direction of the exhaust gas. Since the reflected waves of the closed-end reflection and the open-end reflection are different in phase by 180 degrees as described above, they cancel each other and the sound pressure level of the exhaust sound is reduced.
  • the outlet pipe 33 reduces the sound pressure level (dB) of the primary components f 1 and f 2 of the specific frequency that are particularly problematic as shown in FIG.
  • the valve body 65 When the engine speed Ne (rpm) is relatively high, as shown in FIG. 14, the valve body 65 is opened by the exhaust gas flowing through the exhaust passage 51c, passes through the communication hole 63a, and enters the large passage 61f. And is exhausted into the atmosphere from the atmosphere opening end 61b. Similarly to when the engine speed Ne is relatively low, the exhaust gas flowing in the exhaust passage 51c flows into the small passage 61g from the inlet 62a and is exhausted into the atmosphere from the outlet 62b.
  • the valve body 65 opens, so that the back pressure of the exhaust gas does not increase and the load on the engine 10 does not increase.
  • the exhaust device 20 includes the muffler 30, and the muffler 30 includes an outlet pipe 33 having an exhaust passage 61c.
  • the exhaust passage 61c is divided into a large passage 61f having a large passage sectional area and a small passage 61g having a small passage sectional area.
  • a valve body 65 that swings about a swing shaft 64 so as to vary the flow rate of the exhaust gas flowing through the exhaust gas.
  • the length L 1 of the small passage 61g is, in the exhaust passage 51c, 1/4 of the length L of the 61c of the outlet pipe 33 Has been.
  • the exhaust device 20 it is not necessary to install a sub-muffler in the tail pipe or an exhaust passage opening / closing mechanism in the main muffler, and at a specific frequency due to air column resonance generated in the exhaust system with a simple structure.
  • the particle speed of the exhaust sound can be reduced, and the weight and manufacturing cost can be reduced.
  • the sound pressure of the exhaust sound propagating from the engine 10 can be reduced in the expansion chamber 30A of the muffler 30 over a wide frequency band other than the specific frequencies f 1 and f 2 described above. effective.
  • the Helmholtz resonance occurs in the resonance chamber 30B. Can be excited, and the sound pressure level at the air column resonance peak of the exhaust system can be reduced.
  • the valve body 65 When the engine speed Ne is relatively low, the valve body 65 is closed, and the exhaust gas is exhausted into the atmosphere through the small passage 61g. Therefore, the exhaust gas traveling in the small passage 61g is exhausted.
  • the sound particle velocity can be significantly suppressed in the small passage 61g. As a result, an increase in air column resonance excited in the outlet pipe 33 is remarkably suppressed.
  • a small passage 61g is formed in a length L 1 along the exhaust direction, it is possible to relatively increase the height tolerance of dimensional accuracy of L 2 of the small passage 61g, processing steps or assembling steps Can be reduced, and the yield of producing good products can be increased, and as a result, the manufacturing cost can be reduced.
  • the conventional exhaust device has a structure in which there is no passage corresponding to the small passage 61g, and an opening having a small cross-sectional area is simply formed.
  • an opening having a small cross-sectional area is simply formed.
  • the exhaust device 20 according to the embodiment has an effect that the necessity of forming with such high accuracy is eliminated.
  • the valve body 65 When the engine speed Ne is relatively high, the valve body 65 is opened due to the flow of exhaust gas, and the exhaust gas flows into the large passage 61f through the communication hole 63a, and enters the atmosphere from the atmospheric opening end 61b. Exhausted. As a result, the back pressure of the exhaust gas does not increase, and the effect that the load on the engine 10 does not increase is obtained.
  • the outlet pipe may be configured with a shape and structure other than the rectangular pipe portion 52 of the embodiment.
  • the outlet pipe 70 is configured by a pipe portion 72 whose upper part of the outer periphery is square and whose lower part is semicircular, and the valve body 65 is pressed against the communication member 63. Also good.
  • the pipe portion 72 includes a pipe body 81, a partition member 82, a communication member 83, the swing shaft 64 of the embodiment, a valve body 85, and a pressing member 86, and the rectangular pipe portion 52 of the embodiment. It is constituted similarly.
  • the pipe body 81 has an upper part formed in a square shape and a lower part formed in a semicircular shape, and the other structure is the same as that of the square pipe part 52.
  • the partition member 82 is formed of a semicircular plate material, and is attached to the inside of the pipe body 81 so as to partition the exhaust passage into a large passage 81f having a large passage sectional area and a small passage 81g having a small passage sectional area. .
  • the communication member 83 is formed of a plate material having a rectangular upper part and a semicircular lower part, and is attached to the inside of the pipe body 81 so as to be located upstream of the partition member 82 in the exhaust direction.
  • the communication member 83 includes a communication hole 83a through which exhaust gas flows into the large passage 81f. The exhaust gas in the exhaust passage flows into the large passage 81f through the communication hole 83a. .
  • the valve body 85 is formed of a plate material having a square upper part and a semicircular lower part, and the other structure is configured in the same manner as the valve body 65 of the embodiment.
  • the pressing member 86 is composed of, for example, a coil spring provided at the other end portion 64 b of the swing shaft 64, and is configured to press the valve body 85 against the communication member 83. Further, as another structure of the pressing member 86, a weight may be provided at the lower portion of the valve body 65, and the valve body 85 may be pressed against the communication member 83 by this weight.
  • the same effect as the outlet pipe 33 of the embodiment can be obtained in the outlet pipe 70.
  • installation of a sub-muffler on the tail pipe and installation of an exhaust passage opening / closing mechanism on the main muffler are not required, and the particle velocity of exhaust sound with a specific frequency due to air column resonance generated in the exhaust system is reduced with a simple structure. It is possible to reduce the weight and manufacturing cost.
  • the communication hole 83a of the communication member 83 can be reliably closed by the valve body 65, and the valve body 65 can be stably maintained closed when the flow rate of the exhaust gas is small.
  • the partition member 62 of the rectangular pipe portion 52 of the outlet pipe 33 is configured such that the end portion thereof is positioned at the atmospheric opening end 61 b. explained.
  • the end of the partition member that partitions the exhaust passage into the large passage and the small passage may be positioned at the other opening end. That is, it can be configured such that the end of the partition member is arranged at a position where the particle velocity in the standing wave of air column resonance generated in the exhaust system becomes high.
  • edge part of a partition member may be located in the expansion chamber opening end 51a opened to the expansion chamber 30A of the outlet pipe 33 shown in FIG. 4 which concerns on embodiment.
  • edge part of a partition member may be located in the upstream opening end 25b of the tail pipe 25 shown in FIG. 1 which concerns on embodiment.
  • the length L 1 (1/4) the length of the non-L.
  • the length L 1 may be selected as appropriate depending on the range of particle velocities in the wave.
  • the exhaust device eliminates the need for installing a sub-muffler in the tail pipe and installing an opening / closing mechanism for the exhaust passage in the main muffler, and has an air column generated in the exhaust system with a simple structure. Since the particle velocity of the exhaust sound having a specific frequency due to resonance can be reduced, and the weight and manufacturing cost can be reduced, the exhaust device is useful in general.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Exhaust Silencers (AREA)

Abstract

La présente invention concerne le problème lié à la mise en œuvre d'un dispositif d'échappement qui rend inutile l'installation d'un silencieux secondaire sur un tuyau d'échappement arrière et l'installation d'un mécanisme d'ouverture/de fermeture d'un passage d'échappement sur le silencieux principal, et qui est en mesure de réduire la vitesse acoustique des particules du son d'échappement d'une fréquence spécifique en raison d'une résonance de la colonne d'air ayant lieu dans un système d'échappement, et concerne aussi la réduction du poids et du coût de fabrication, au moyen d'une simple construction. Le dispositif d'échappement est équipé d'un tuyau de sortie (33) ayant un passage d'échappement (61c) qui permet de faire circuler le gaz d'échappement en provenance d'une extrémité d'ouverture d'entrée jusqu'à une extrémité d'ouverture de mise à l'air libre (61b) qui évacue le gaz d'échappement dans l'atmosphère. De plus, le dispositif d'échappement comporte : un élément de séparation (62) qui divise le passage d'échappement (61c) en un grand passage (61f) et un petit passage (61g) ; un élément de raccordement (63) équipé d'un trou de raccordement (63a) qui raccorde le grand passage (61f) et le passage d'échappement (61c) ; un arbre de pivot (64) attaché à la partie paroi du tuyau de sortie (33) ; et un élément de robinetterie (65) qui est soumis à l'écoulement de l'air évacué et qui par conséquent oscille autour de l'arbre de pivot (64) de manière à changer le débit-volume du gaz d'échappement traversant le trou de raccordement (63a).
PCT/JP2010/007538 2010-12-27 2010-12-27 Dispositif d'échappement WO2012090238A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/JP2010/007538 WO2012090238A1 (fr) 2010-12-27 2010-12-27 Dispositif d'échappement

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Application Number Priority Date Filing Date Title
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WO2012090238A1 true WO2012090238A1 (fr) 2012-07-05

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109218900A (zh) * 2018-09-06 2019-01-15 东莞精恒电子有限公司 一种多角度旋转音响及其使用方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5490522U (fr) * 1977-12-08 1979-06-27
JPS5864814U (ja) * 1981-10-28 1983-05-02 日産自動車株式会社 内燃機関の排気消音装置

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5490522U (fr) * 1977-12-08 1979-06-27
JPS5864814U (ja) * 1981-10-28 1983-05-02 日産自動車株式会社 内燃機関の排気消音装置

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109218900A (zh) * 2018-09-06 2019-01-15 东莞精恒电子有限公司 一种多角度旋转音响及其使用方法
CN109218900B (zh) * 2018-09-06 2023-08-15 东莞精恒电子有限公司 一种多角度旋转音响及其使用方法

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