Active noise reduction combined type silencer

Abstract

The invention relates to the technical field of automobile noise reduction, in particular to an active noise reduction composite silencer which comprises a containing shell, a plurality of partition plates are arranged in the containing shell and divide an inner cavity of the containing shell into a pressure relief cavity, a head noise reduction cavity, an expansion cavity, a tail noise reduction cavity and a cavity, an air inlet pipe is connected to the containing shell, and the front partition plate and the rear partition plate are removed. And a first-stage noise reduction mechanism and a second-stage noise reduction mechanism are arranged in the head noise reduction cavity and the tail noise reduction cavity correspondingly, a high-pressure pneumatic valve is further arranged in the head noise reduction cavity, a first exhaust pipe and a second exhaust pipe are arranged in the containing shell, and perforated passive noise reduction mechanisms are arranged on the first exhaust pipe and the second exhaust pipe. The first-stage noise reduction mechanism plays a leading role in low-frequency noise reduction, and the second-stage noise reduction mechanism plays a leading role in high-frequency noise reduction, so that in the actual driving process, waste gas noise generated in different driving states of an automobile can be dynamically adapted through the first-stage noise reduction mechanism and the second-stage noise reduction mechanism.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile noise reduction, and in particular to an active noise reduction composite muffler. Background Art

[0002] The active noise reduction composite automobile muffler is an automobile exhaust noise control device that combines active noise reduction technology with traditional passive noise reduction structure. It can not only attenuate noise through physical structure (passive noise reduction), but also offset noise by actively emitting anti-phase sound waves (active noise reduction), thereby achieving more efficient noise reduction effects over a wide frequency range (especially low-frequency noise that traditional mufflers are difficult to handle). It is widely used to improve the quietness of automobile driving.

[0003] The existing Chinese patent with publication number CN211851959U discloses a muffler for active noise reduction of automobiles to solve the problem of single muffler technology in existing mufflers. However, the above patent also has the following defects: First, because there are several sound-absorbing fillers between the micro-sonic wave generator and the noise, when the micro-sonic wave generator is turned on, the sound waves generated by the micro-sonic wave generator will be weakened by the sound-absorbing fillers. Ultimately, the sound waves generated by the micro-sonic wave generator are difficult to offset the noise in the silencer tube, reducing the effect of active noise reduction; Secondly, the noise audio generated by the engine of a car is different under different driving conditions. When the car is idling, low-frequency noise is often dominant, and low-frequency noise is usually concentrated in the muffler inlet section. When the car is driving at high speed, high-frequency noise is often dominant, and high-frequency noise usually diffuses in the entire muffler cavity. Therefore, the active noise reduction function of the above-mentioned patent and traditional muffler cannot dynamically adapt to the noise generated by the car under different driving conditions, which ultimately leads to poor noise reduction effect.

[0004] Therefore, it is necessary to provide an active noise reduction composite muffler to solve the above problems. Summary of the Invention

[0005] Based on this, it is necessary to provide an active noise reduction composite muffler to address the existing technical problems.

[0006] In order to solve the problems of the existing technology, the technical solution adopted by the present invention is: an active noise reduction composite silencer, comprising a horizontally arranged containing shell, a plurality of vertical partitions are provided in the containing shell, the plurality of partitions divide the inner cavity of the containing shell into a pressure relief chamber, a head noise reduction chamber, an expansion chamber, a tail noise reduction chamber and a cavity along its length direction, an air intake pipe leading to the head noise reduction chamber is connected to the containing shell, and except for the head and tail partitions, the remaining partitions are provided with vents, and the head noise reduction chamber and the tail noise reduction chamber are respectively provided with a first-level noise reduction mechanism and a second-level noise reduction mechanism for actively reducing the noise of the exhaust gas in sequence, a high-pressure pneumatic valve for supplying the exhaust gas to flow into the pressure relief chamber under high pressure is also provided in the head noise reduction chamber, and a No. 1 exhaust pipe and a No. 2 exhaust pipe are provided in the containing shell for discharging the exhaust gas in the pressure relief chamber and the tail noise reduction chamber respectively, the No. 1 exhaust pipe and the No. 2 exhaust pipe both pass through the expansion chamber, and the No. 1 exhaust pipe and the No. 2 exhaust pipe are provided with a perforated passive silencer located in the expansion chamber.

[0007] Furthermore, the first-level noise reduction mechanism includes a No. 1 microphone and a cone speaker. A sound-transparent air guide cover fixedly connected to the adjacent partition is provided in the first noise reduction cavity. The cone speaker is fixed in the sound-transparent air guide cover, and the sound waves of the cone speaker are directed toward the air intake pipe. A vertical No. 1 sound-transparent protective tube is fixed on the air intake pipe. The lower end of the No. 1 sound-transparent protective tube penetrates into the air intake pipe, and the No. 1 microphone is fixed in the No. 1 sound-transparent protective tube.

[0008] Furthermore, the secondary noise reduction mechanism includes a No. 2 microphone and a dome-shaped speaker. An air collecting pipe and a sound-transparent protective cover are fixed on the two partitions adjacent to the tail noise reduction cavity respectively. The air collecting pipe is connected to the corresponding air vent. A vertical No. 2 sound-transparent protective tube is fixed in the air collecting pipe. The lower end of the No. 2 sound-transparent protective tube passes through the air collecting pipe. The No. 2 microphone is fixed in the No. 2 sound-transparent protective tube. The dome-shaped speaker is fixed in the sound-transparent protective cover, and the sound waves of the dome-shaped speaker are directed toward the air collecting pipe.

[0009] Furthermore, the containment shell is a curved rectangular shape, the end edges of the containment shell are composed of arc-shaped surfaces, each partition is rectangular, and both ends of each partition are formed with round heads that fit the arc-shaped surfaces, the vents are close to the round heads of the partitions, and adjacent vents are staggered.

[0010] Furthermore, exhaust pipe No. 1 includes straight pipe No. 1, bent pipe No. 1 and tail pipe No. 1. Straight pipe No. 1 is horizontally arranged in the containment shell. Straight pipe No. 1 passes through several partitions in sequence. The two ends of straight pipe No. 1 are respectively located in the pressure relief chamber and the cavity. Tail pipe No. 1 is parallel to straight pipe No. 1 and is arranged outside the containment shell. Bend pipe No. 1 connects the end of straight pipe No. 1 located in the cavity with tail pipe No. 1.

[0011] Furthermore, the No. 2 exhaust pipe includes a No. 2 straight pipe, a No. 2 bent pipe and a No. 2 tail pipe. The No. 2 straight pipe is arranged below the No. 1 straight pipe, and the No. 2 straight pipe is parallel to the No. 1 straight pipe. The No. 2 straight pipe passes through several partitions in sequence. The two ends of the No. 2 straight pipe are respectively located in the pressure relief chamber and the tail noise reduction chamber. The No. 2 tail pipe is parallel to the No. 1 tail pipe and is arranged outside the containment shell. The No. 2 bent pipe connects the end of the No. 2 straight pipe located in the pressure relief chamber with the No. 2 tail pipe.

[0012] Furthermore, the perforated passive silencer mechanism includes a silencer drum, a rotating drive member and a silencer sleeve. There are several expansion cavities. The parts where the No. 1 straight pipe and the No. 2 straight pipe pass through the expansion cavity are both silencer sections. The silencer sections are provided with several groups of No. 1 silencer holes equidistantly distributed along their axial directions, and each group of No. 1 silencer holes is in a circular array. The silencer drum is rotatably sleeved on the corresponding silencer section. The silencer drum is provided with several groups of No. 2 silencer holes equidistantly distributed along their axial directions, and each group of No. 2 silencer holes is in a circular array. The silencer sleeve is sleeved on the corresponding silencer drum, and the rotating drive member is used to synchronously drive several silencer drums to rotate.

[0013] Furthermore, both ends of the silencer drum are coaxially formed with columnar expansion sleeves, and a bearing is provided between the columnar expansion sleeve and the silencer section.

[0014] Furthermore, the rotating drive component includes a No. 1 gear ring, a No. 2 gear ring, a gear and a drive shaft. The No. 1 gear ring and the No. 2 gear ring are coaxially fixed to the silencer drum on the No. 1 straight pipe and the No. 2 straight pipe respectively, and the No. 1 gear ring is meshed with the No. 2 gear ring. A mounting shell is fixedly provided at the bottom of the accommodating shell, and the mounting shell is communicated with the corresponding expansion chamber. The gear is rotatably arranged in the mounting shell, and the gear is meshed with the No. 2 gear ring. The drive shaft is horizontally arranged at the bottom of the accommodating shell, and the drive shaft coaxially connects several gears.

[0015] Furthermore, the high-pressure pneumatic valve includes a connecting seat, a valve plate, a sealing plate and several springs. The connecting seat is arranged in the head noise reduction cavity, and the connecting seat is fixedly connected to the adjacent partition. A accommodating cavity is provided in the connecting seat, and the valve plate vertically covers the accommodating cavity. Several sliding rods slidably connected to the connecting seat are formed on the valve plate. Each spring is sleeved on the sliding rod, and the valve plate presses the spring into the accommodating cavity. A limiting nut is screwed on the end of the sliding rod. A pressure relief port is opened on the partition next to the pressure relief cavity. The sealing plate is fixedly connected to the valve plate, and the sealing plate blocks the pressure relief port.

[0016] Compared with the prior art, the present invention has the following beneficial effects: First, the primary and secondary noise reduction mechanisms of the device, which are used to actively reduce noise, are separately arranged from the perforated passive noise reduction mechanism, thereby improving the active noise reduction effects of the primary and secondary noise reduction mechanisms. Ultimately, after several rounds of noise reduction, the noise carried by the exhaust gas will be effectively weakened. Secondly, the primary noise reduction mechanism plays a leading role in low-frequency noise reduction, while the secondary noise reduction mechanism plays a leading role in high-frequency noise reduction. Therefore, during actual driving, the primary and secondary noise reduction mechanisms can dynamically adapt to the exhaust noise generated by the car in different driving conditions, thereby improving the noise reduction effect. Third, the perforated passive silencer can change the noise perforation rate according to the different driving conditions of the car during actual driving. When the car is idling, the noise perforation rate is low, which can effectively weaken low-frequency noise. When the car is driving at high speed, the noise perforation rate is high, which can effectively weaken high-frequency noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention; Figure 2 is a sectional view of the three-dimensional structure of the containment shell; Figure 3 It is a three-dimensional structural cross-sectional view of the perforated passive silencer mechanism; Figure 4 yes Figure 3 A1 is a partial enlarged schematic diagram; Figure 5 It is a sectional view of the three-dimensional structure of the secondary noise reduction mechanism; Figure 6 It is a sectional view of the three-dimensional structure of the first-level noise reduction mechanism; Figure 7 It is a planar cross-sectional view of a high-pressure pneumatic valve; Figure 8 This is a schematic diagram of the three-dimensional structure of the No. 1 exhaust pipe; Figure 9 This is a schematic diagram of the three-dimensional structure of the No. 2 exhaust pipe; Figure 10 It is a schematic diagram of the three-dimensional structure of the silencer drum.

[0018] The numbers in the figure are: 1. Containment shell; 2. Partition; 3. Pressure relief chamber; 4. Noise reduction chamber at the front; 5. Expansion chamber; 6. Noise reduction chamber at the rear; 7. Cavity; 8. Inlet pipe; 9. Vent; 10. High-pressure pneumatic valve; 11. Exhaust pipe No. 1; 12. Exhaust pipe No. 2; 13. Perforated passive silencer; 14. Microphone No. 1; 15. Cone speaker; 16. Sound-transmitting guide cover; 17. No. 1 sound-transmitting protective tube; 18. No. 2 microphone; 19. Dome speaker; 20. Collecting pipe; 21. Sound-transmitting protective cover; 22. No. 2 sound-transmitting protective tube; 23. Curved surface; 24. Circle Head; 25. Straight pipe No. 1; 26. Bend pipe No. 1; 27. Tail pipe No. 1; 28. Straight pipe No. 2; 29. ​​Bend pipe No. 2; 30. Tail pipe No. 2; 31. Silencer drum; 32. Silencer sleeve; 33. Silencer section; 34. Silencer hole No. 1; 35. Silencer hole No. 2; 36. Columnar expansion sleeve; 37. Bearing; 38. Gear ring No. 1; 39. Gear ring No. 2; 40. Gear; 41. Drive shaft; 42. Mounting shell; 43. Connecting seat; 44. Valve plate; 45. Sealing plate; 46. Spring; 47. Accommodating chamber; 48. Slide rod; 49. Limit nut; 50. Pressure relief port. DETAILED DESCRIPTION

[0019] In order to further understand the features, technical means, specific objectives and functions achieved by the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] refer to Figures 1 to 10 The active noise reduction composite muffler shown in the figure includes a horizontally arranged housing 1, and a plurality of vertical partitions 2 are provided in the housing 1. The plurality of partitions 2 divide the inner cavity of the housing 1 into a pressure relief chamber 3, a head noise reduction chamber 4, an expansion chamber 5, a tail noise reduction chamber 6 and a cavity 7 in sequence along its length direction. The housing 1 is connected to an air intake pipe 8 leading to the head noise reduction chamber 4. Except for the head and tail partitions 2, the remaining partitions 2 are provided with vents 9. The head noise reduction chamber 4 and the tail noise reduction chamber 6 are respectively provided with A first-stage noise reduction mechanism and a second-stage noise reduction mechanism are used to actively reduce the noise of the exhaust gas in sequence. A high-pressure pneumatic valve 10 is also provided in the head noise reduction chamber 4 for allowing the exhaust gas to flow into the pressure relief chamber 3 under high pressure. A No. 1 exhaust pipe 11 and a No. 2 exhaust pipe 12 are provided in the accommodating shell 1 for discharging the exhaust gas in the pressure relief chamber 3 and the tail noise reduction chamber 6 respectively. The No. 1 exhaust pipe 11 and the No. 2 exhaust pipe 12 both pass through the expansion chamber 5, and the No. 1 exhaust pipe 11 and the No. 2 exhaust pipe 12 are provided with a perforated passive silencer mechanism 13 located in the expansion chamber 5.

[0021] In actual use, the air intake pipe 8 of the device is connected to a catalytic converter (not shown in the figure), and the catalytic converter is connected to the exhaust manifold of the engine (not shown in the figure). When the engine is running, the exhaust gas generated by the engine flows through the exhaust manifold to the catalytic converter, and the pollutants in the exhaust gas are removed by the catalytic converter, thereby ultimately reducing the emission of pollutants. The exhaust gas purified by the catalytic converter flows into the head noise reduction chamber 4 along the intake pipe 8. At this time, the first-level noise reduction mechanism arranged in the head noise reduction chamber 4 will perform the first active noise reduction on the noise carried by the exhaust gas. After the exhaust gas flows into the head noise reduction chamber 4, the exhaust gas flows to the expansion chamber 5 through the corresponding vent 9. In this process, the noise carried by the exhaust gas is gradually attenuated through the reflection, interference and impedance mismatch of the sound waves. After the exhaust gas flows through the expansion chamber 5, the exhaust gas will flow to the tail noise reduction chamber 6 through the corresponding vent 9. At this time, the secondary noise reduction mechanism provided in the tail noise reduction chamber 6 will perform a secondary active noise reduction on the noise carried by the exhaust gas. After that, the exhaust gas will flow in the opposite direction through the No. 2 exhaust pipe 12 and be discharged from the containment shell 1 after passing through the expansion chamber 5, the head noise reduction chamber 4 and the pressure relief chamber 3 in sequence. During this process, the exhaust gas entering the No. 2 intake pipe 8 will be weakened by the perforated passive silencer 13 when passing through the expansion chamber 5. Finally, the exhaust gas that has undergone multiple noise reductions will produce very little noise when it is discharged. When the car is running at high speed, the amount of exhaust gas discharged from the upstream increases. When the exhaust gas flows into the head noise reduction chamber 4, the air pressure in the head noise reduction chamber 4 will increase instantly. At this time, the high-pressure pneumatic valve 10 will guide part of the exhaust gas to the pressure relief chamber 3 to balance the air pressure in the head noise reduction chamber 4. The exhaust gas entering the pressure relief chamber 3 will follow the No. 1 exhaust pipe 11 and pass through the head noise reduction chamber 4, the expansion chamber 5 and the tail noise reduction chamber 6 in turn before being discharged from the containing shell 1. When the exhaust gas in the No. 1 exhaust pipe 11 passes through the expansion chamber 5, the perforated passive silencer mechanism 13 will reduce the noise carried by the exhaust gas. The noise of exhaust gas discharged from the No. 1 exhaust pipe 11 is weakened, thereby reducing the noise of exhaust gas discharged from the No. 1 exhaust pipe 11. Since the high-pressure pneumatic valve 10 will only guide the exhaust gas to the pressure relief chamber 3 when the air pressure in the head noise reduction chamber 4 increases instantaneously, the amount of exhaust gas flowing into the pressure relief chamber 3 is small, so only a small amount of noise will flow into the pressure relief chamber 3 along with the exhaust gas. When the noise enters the pressure relief chamber 3, the noise will gradually attenuate through the reflection, interference and impedance mismatch of the sound wave, and the subsequent perforated passive silencer mechanism 13 will further weaken the noise. Finally, the noise generated when the exhaust gas is discharged from the No. 1 exhaust pipe 11 will be very small.

[0022] In order to show the specific structure of the first-level noise reduction mechanism, the following features are set: The first-level noise reduction mechanism includes a No. 1 microphone 14 and a cone speaker 15. A sound-transparent air guide cover 16 fixedly connected to the adjacent partition 2 is provided in the head noise reduction cavity 4. The cone speaker 15 is fixed in the sound-transparent air guide cover 16, and the sound waves of the cone speaker 15 are directed toward the air intake pipe 8. A vertical No. 1 sound-transparent protective tube 17 is fixed on the air intake pipe 8. The lower end of the No. 1 sound-transparent protective tube 17 penetrates into the air intake pipe 8, and the No. 1 microphone 14 is fixed in the No. 1 sound-transparent protective tube 17.

[0023] When the exhaust gas from upstream flows into the intake pipe 8, the noise carried by the exhaust gas will pass through the No. 1 microphone 14, and the noise will be collected by the No. 1 microphone 14. In actual use, the car is equipped with a host computer (not shown in the figure) and a controller (not shown in the figure). The noise data collected by the No. 1 microphone 14 will be transmitted to the host computer, which will analyze the current noise and generate an anti-phase sound wave signal with the same frequency, equal amplitude and opposite phase as the original noise in real time. After that, the controller will transmit the anti-phase sound wave signal to the cone speaker 15, so that it releases the anti-phase sound wave toward the noise source, and finally cancels it out through the interference of the sound waves. Part of the noise energy, among which, when the exhaust gas enters the containment shell 1, the low-frequency noise will be concentrated at the mouth of the air intake pipe 8. Since the first-level noise reduction mechanism is close to the noise source, and the sound waves generated by the cone speaker 15 can effectively weaken the low-frequency sound waves in the noise, then when dealing with low-frequency noise, the first-level noise reduction mechanism plays a leading role. The sound-transparent guide cover 16 and the first sound-transparent protective tube 17 are both made of sound-transparent materials, and the structure is double-layer, the base layer is a porous ceramic plate, and the surface is composited with a layer of metal micro-perforated plate. Through the above structure, the sound-transparent guide cover 16 and the first sound-transparent protective tube 17 can take into account both heat insulation and sound wave penetration.

[0024] In order to show the specific structure of the secondary noise reduction mechanism, the following features are set: The secondary noise reduction mechanism includes a No. 2 microphone 18 and a dome-shaped speaker 19. An air collecting pipe 20 and a sound-transparent protective cover 21 are fixed on the two partitions 2 adjacent to the tail noise reduction cavity 6 respectively. The air collecting pipe 20 is connected to the corresponding air vent 9. A vertical No. 2 sound-transparent protective tube 22 is fixed in the air collecting pipe 20. The lower end of the No. 2 sound-transparent protective tube 22 passes into the air collecting pipe 20. The No. 2 microphone 18 is fixed in the No. 2 sound-transparent protective tube 22. The dome-shaped speaker 19 is fixed in the sound-transparent protective cover 21, and the sound waves of the dome-shaped speaker 19 are directed toward the air collecting pipe 20.

[0025] The exhaust gas in the expansion chamber 5 enters the tail noise reduction chamber 6 through the air collecting pipe 20. During this process, the noise carried by the exhaust gas will pass through the second microphone 18. The second microphone 18 collects the noise. After analysis by the host computer (not shown in the figure), the controller (not shown in the figure) will transmit the anti-phase sound wave signal to the dome-shaped speaker 19, so that it releases the anti-phase sound wave toward the noise source, and finally offsets part of the noise energy through the interference of the sound waves. When the car is running at high speed, the noise carried by the exhaust gas is in the form of high-frequency noise. The high-frequency noise will quickly diffuse into the containment shell 1. In this process, the diffused high-frequency noise is weakened by the expansion cavity 5 and the secondary noise reduction mechanism. Therefore, when dealing with high-frequency noise, the expansion cavity 5 and the secondary noise reduction mechanism play a leading role. The sound-transmitting shield 21 and the second sound-transmitting shield 22 are both made of sound-transmitting materials, and the structure is double-layer. The base layer is a porous ceramic plate, and the surface is composited with a layer of metal micro-perforated plate. Through the above structure, the sound-transmitting shield 21 and the second sound-transmitting shield 22 can take into account both heat insulation and sound wave penetration.

[0026] In order to show the specific structure of the containment shell 1 and the partition 2, the following features are set: The containment shell 1 is a curved rectangular shape, and the end edges of the containment shell 1 are composed of an arc-shaped surface 23. Each partition 2 is rectangular, and both ends of each partition 2 are formed with a round head 24 that fits the arc-shaped surface 23. The vent 9 is close to the round head 24 of the partition 2, and adjacent vents 9 are staggered.

[0027] The space inside a car chassis or engine compartment is compact and irregular in shape. The curved rectangular containment shell 1 can flexibly avoid surrounding components on a roughly rectangular basis through its curved surface design, thus preventing interference with other parts. When exhaust gas enters the containment shell 1, the curved surface 23 of the containment shell 1 indirectly affects the flow path of the internal airflow and the reflection mode of sound waves, thereby preventing additional noise caused by the vibration of the containment shell 1. At the same time, in conjunction with the expansion cavity 5, it can more efficiently absorb or reflect sound waves, thereby improving the noise reduction efficiency. The staggered distribution of the vent holes 9 can prevent the gas from flowing directly through the expansion cavity 5 along the vent holes 9, so that when noise enters the expansion cavity 5, the sound waves can be reflected between the two partitions 2, further improving the noise reduction efficiency.

[0028] To illustrate how the No. 1 exhaust pipe 11 is installed, the following features are provided: The No. 1 exhaust pipe 11 includes a No. 1 straight pipe 25, a No. 1 curved pipe 26 and a No. 1 tail pipe 27. The No. 1 straight pipe 25 is horizontally arranged in the containment shell 1. The No. 1 straight pipe 25 passes through several partitions 2 in sequence. The two ends of the No. 1 straight pipe 25 are respectively located in the pressure relief chamber 3 and the cavity 7. The No. 1 tail pipe 27 is parallel to the No. 1 straight pipe 25. The No. 1 tail pipe 27 is arranged outside the containment shell 1. The No. 1 curved pipe 26 connects the end of the No. 1 straight pipe 25 located in the cavity 7 with the No. 1 tail pipe 27.

[0029] The exhaust gas in the pressure relief chamber 3 will flow into the No. 1 straight pipe 25 due to the pressure difference. The exhaust gas entering the No. 1 straight pipe 25 will pass through the head noise reduction chamber 4, the expansion chamber 5 and the tail noise reduction chamber 6 in turn and flow into the No. 1 curved pipe 26. Finally, the exhaust gas will be discharged along the No. 1 tail pipe 27.

[0030] The No. 2 exhaust pipe 12 includes a No. 2 straight pipe 28, a No. 2 bent pipe 29 and a No. 2 tail pipe 30. The No. 2 straight pipe 28 is arranged below the No. 1 straight pipe 25, and the No. 2 straight pipe 28 is parallel to the No. 1 straight pipe 25. The No. 2 straight pipe 28 passes through several partitions 2 in sequence. The two ends of the No. 2 straight pipe 28 are respectively located in the pressure relief chamber 3 and the tail noise reduction chamber 6. The No. 2 tail pipe 30 is parallel to the No. 1 tail pipe 27. The No. 2 tail pipe 30 is arranged outside the containing shell 1, and the No. 2 bent pipe 29 connects the end of the No. 2 straight pipe 28 located in the pressure relief chamber 3 with the No. 2 tail pipe 30.

[0031] The exhaust gas in the tail noise reduction chamber 6 flows into the No. 2 straight pipe 28 due to the pressure difference and the push of the subsequent exhaust gas. The exhaust gas entering the No. 2 straight pipe 28 will successively pass through the expansion chamber 5 and the head pressure relief chamber 3 and flow into the No. 2 bend pipe 29, and finally the exhaust gas will be discharged along the No. 2 tail pipe 30.

[0032] In order to show the specific structure of the perforated passive silencer mechanism 13, the following features are provided: The perforated passive silencer mechanism 13 includes a silencer drum 31, a rotating drive member and a silencer sleeve 32. The number of expansion chambers 5 is several. The parts where the No. 1 straight pipe 25 and the No. 2 straight pipe 28 pass through the expansion chamber 5 are both silencer sections 33. The silencer section 33 is provided with several groups of No. 1 silencer holes 34 equidistantly distributed along its axial direction. Each group of No. 1 silencer holes 34 is in a circular array. The silencer drum 31 is rotatably sleeved on the corresponding silencer section 33. The silencer drum 31 is provided with several groups of No. 2 silencer holes 35 equidistantly distributed along its axial direction. Each group of No. 2 silencer holes 35 is in a circular array. The silencer sleeve 32 is sleeved on the corresponding silencer drum 31. The rotating drive member is used to synchronously drive several silencer drums 31 to rotate.

[0033] Since the perforated passive silencer mechanism 13 provided on the No. 1 exhaust pipe 11 and the No. 2 exhaust pipe 12 has the same function, the perforated passive silencer mechanism 13 on the No. 1 exhaust pipe 11 is taken as an example. The silencer section 33 and the silencer drum 31 are the core components of the passive silencer structure. When the exhaust gas flows into the No. 1 straight pipe 25, the No. 1 silencer hole 34 and the No. 2 silencer hole 35 dissipate the sound waves through transmission and resonance, thereby attenuating noise in a specific frequency band. When the car is idling, the noise carried by the exhaust gas is mainly low-frequency noise. At this time, the silencer drum 31 will rotate to make some of the No. 2 silencer holes 35 and the No. 1 silencer holes 34 interlaced, thereby reducing the amount of actual noise passing through the No. 1 silencer holes 34 and the No. 2 silencer holes 35, so that the resonant frequency of the silencer section 33 and the silencer drum 31 shifts toward low frequency, and ultimately can effectively weaken the low-frequency noise. When the car is running at high speed, the noise carried by the exhaust gas is mainly high-frequency noise. At this time, the silencer drum 31 will rotate to make all the No. 2 silencer holes 35 connect with the No. 1 silencer holes 34, so as to increase the amount of actual noise passing through the No. 1 silencer holes 34 and the No. 2 silencer holes 35, so that the resonant frequency of the silencer section 33 and the silencer drum 31 shifts toward high frequency, and ultimately can effectively weaken the high-frequency noise. When the noise passes through the No. 1 silencer holes 34 and the No. 2 silencer holes 35, it will pass through the silencer sleeve 32, and at this time the silencer sleeve 32 further weakens the noise.

[0034] In order to show how the muffler drum 31 is rotatably connected to the muffler section 33, the following features are provided: Both ends of the muffler drum 31 are coaxially formed with columnar expansion sleeves 36 , and a bearing 37 is provided between the columnar expansion sleeve 36 and the muffler section 33 .

[0035] The cylindrical expansion sleeves 36 at both ends of the silencer drum 31 are connected to the corresponding silencer sections 33 through bearings 37 , so that the silencer drum 31 can rotate on the silencer sections 33 .

[0036] In order to show the specific structure of the rotary drive, the following features are set: The rotating drive component includes a No. 1 gear ring 38, a No. 2 gear ring 39, a gear 40 and a drive shaft 41. The No. 1 gear ring 38 and the No. 2 gear ring 39 are coaxially fixed to the silencer drum 31 on the No. 1 straight tube 25 and the No. 2 straight tube 28 respectively, and the No. 1 gear ring 38 is meshed with the No. 2 gear ring 39. A mounting shell 42 is fixedly provided at the bottom of the accommodating shell 1. The mounting shell 42 is communicated with the corresponding expansion chamber 5. The gear 40 is rotatably arranged in the mounting shell 42, and the gear 40 is meshed with the No. 2 gear ring 39. The drive shaft 41 is horizontally arranged at the bottom of the accommodating shell 1, and the drive shaft 41 coaxially fixes several gears 40.

[0037] In actual use, a stepper motor (not shown in the figure) connected to the drive shaft 41 is installed at the bottom of the accommodating shell 1. When the stepper motor is started, the drive shaft 41 will synchronously drive several gears 40 to rotate, so that through the transmission action of the No. 1 gear ring 38 and the No. 2 gear ring 39, each silencer drum 31 will rotate, and finally the silencer drum 31 is used to control the amount of actual noise passing through the No. 1 silencer hole 34 and the No. 2 silencer hole 35.

[0038] In order to show the specific structure of the high-pressure pneumatic valve 10, the following features are set: The high-pressure pneumatic valve 10 includes a connecting seat 43, a valve plate 44, a sealing plate 45 and several springs 46. The connecting seat 43 is arranged in the head noise reduction chamber 4, and the connecting seat 43 is fixedly connected to the adjacent partition 2. A accommodating chamber 47 is provided in the connecting seat 43. The valve plate 44 vertically covers the accommodating chamber 47. Several slide rods 48 slidably connected to the connecting seat 43 are formed on the valve plate 44. Each spring 46 is sleeved on the slide rod 48. The valve plate 44 presses the spring 46 into the accommodating chamber 47. A limiting nut 49 is screwed on the end of the slide rod 48. A pressure relief port 50 is opened on the partition 2 next to the pressure relief chamber 3. The sealing plate 45 is fixedly connected to the valve plate 44, and the sealing plate 45 blocks the pressure relief port 50.

[0039] The exhaust gas flowing into the head noise reduction chamber 4 from the intake pipe 8 will act on the valve plate 44 after passing through the first-level noise reduction mechanism. When the car is running at high speed, the air pressure in the head noise reduction chamber 4 increases. At this time, the air pressure will overcome the elastic force of several springs 46 to drive the valve plate 44 to translate into the accommodating chamber 47. After the valve plate 44 translates, the sealing plate 45 will gradually open the pressure relief port 50, so that the exhaust gas in the head noise reduction chamber 4 will flow to the pressure relief chamber 3, and finally balance the air pressure in the head noise reduction chamber 4. When the air pressure in the head noise reduction chamber 4 gradually decreases, the spring 46 will overcome the air pressure to drive the valve plate 44 to reset. When the sealing plate 45 blocks the pressure relief port 50, the sliding stroke of the slide rod 48 is limited by the limit nut 49 to prevent the slide rod 48 from slipping off the connecting seat 43.

[0040] Working principle: In actual use, the air intake pipe 8 of the device is connected to a catalytic converter (not shown in the figure), and the catalytic converter is connected to the exhaust manifold of the engine (not shown in the figure). When the engine is running, the exhaust gas generated by the engine flows through the exhaust manifold to the catalytic converter, and the pollutants in the exhaust gas are removed by the catalytic converter, thereby ultimately reducing the emission of pollutants. The exhaust gas purified by the catalytic converter flows into the head noise reduction chamber 4 along the intake pipe 8. At this time, the first-level noise reduction mechanism arranged in the head noise reduction chamber 4 will perform the first active noise reduction on the noise carried by the exhaust gas. After the exhaust gas flows into the head noise reduction chamber 4, the exhaust gas flows to the expansion chamber 5 through the corresponding vent 9. In this process, the noise carried by the exhaust gas is gradually attenuated through the reflection, interference and impedance mismatch of the sound waves. After the exhaust gas flows through the expansion chamber 5, the exhaust gas will flow to the tail noise reduction chamber 6 through the corresponding vent 9. At this time, the secondary noise reduction mechanism provided in the tail noise reduction chamber 6 will perform a secondary active noise reduction on the noise carried by the exhaust gas. After that, the exhaust gas will flow in the opposite direction through the No. 2 exhaust pipe 12 and be discharged from the containment shell 1 after passing through the expansion chamber 5, the head noise reduction chamber 4 and the pressure relief chamber 3 in sequence. During this process, the exhaust gas entering the No. 2 intake pipe 8 will be weakened by the perforated passive silencer 13 when passing through the expansion chamber 5. Finally, the exhaust gas that has undergone multiple noise reductions will produce very little noise when it is discharged. When the car is running at high speed, the amount of exhaust gas discharged from the upstream increases. When the exhaust gas flows into the head noise reduction chamber 4, the air pressure in the head noise reduction chamber 4 will increase instantly. At this time, the high-pressure pneumatic valve 10 will guide part of the exhaust gas to the pressure relief chamber 3 to balance the air pressure in the head noise reduction chamber 4. The exhaust gas entering the pressure relief chamber 3 will follow the No. 1 exhaust pipe 11 and pass through the head noise reduction chamber 4, the expansion chamber 5 and the tail noise reduction chamber 6 in turn before being discharged from the containing shell 1. When the exhaust gas in the No. 1 exhaust pipe 11 passes through the expansion chamber 5, the perforated passive silencer mechanism 13 will reduce the noise carried by the exhaust gas. The noise of exhaust gas discharged from the No. 1 exhaust pipe 11 is weakened, thereby reducing the noise of exhaust gas discharged from the No. 1 exhaust pipe 11. Since the high-pressure pneumatic valve 10 will only guide the exhaust gas to the pressure relief chamber 3 when the air pressure in the head noise reduction chamber 4 increases instantaneously, the amount of exhaust gas flowing into the pressure relief chamber 3 is small, so only a small amount of noise will flow into the pressure relief chamber 3 along with the exhaust gas. When the noise enters the pressure relief chamber 3, the noise will gradually attenuate through the reflection, interference and impedance mismatch of the sound wave, and the subsequent perforated passive silencer mechanism 13 will further weaken the noise. Finally, the noise generated when the exhaust gas is discharged from the No. 1 exhaust pipe 11 will be very small.

[0041] The above embodiments merely represent one or several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. An active noise reduction composite muffler, characterized in that: The invention comprises a horizontally arranged housing (1), wherein a plurality of vertical partitions (2) are provided in the housing (1), wherein the plurality of partitions (2) sequentially divide the inner cavity of the housing (1) into a pressure relief cavity (3), a head noise reduction cavity (4), an expansion cavity (5), a tail noise reduction cavity (6) and a cavity (7) along its length direction, and the housing (1) is connected with an air inlet pipe (8) leading to the head noise reduction cavity (4), and excluding the head and tail partitions (2), the remaining partitions (2) are provided with vent holes (9), and the head noise reduction cavity (4) and the tail noise reduction cavity (6) are respectively provided with a pressure relief cavity (3), a head noise reduction cavity (4) and a tail noise reduction cavity (6) for exhaust gas. A first-stage noise reduction mechanism and a second-stage noise reduction mechanism are provided for performing active noise reduction in sequence. A high-pressure pneumatic valve (10) for allowing exhaust gas to flow into a pressure relief chamber (3) under high pressure is further provided in a front noise reduction chamber (4). A first exhaust pipe (11) and a second exhaust pipe (12) for respectively discharging exhaust gas from the pressure relief chamber (3) and the rear noise reduction chamber (6) are provided in a housing (1). Both the first exhaust pipe (11) and the second exhaust pipe (12) pass through an expansion chamber (5), and a perforated passive silencing mechanism (13) located in the expansion chamber (5) is provided on the first exhaust pipe (11) and the second exhaust pipe (12).

2. The active noise reduction composite muffler according to claim 1, characterized in that: The first-level noise reduction mechanism includes a first microphone (14) and a cone speaker (15). A sound-transmitting air guide cover (16) fixedly connected to an adjacent partition (2) is provided in the first noise reduction cavity (4). The cone speaker (15) is fixedly arranged in the sound-transmitting air guide cover (16), and the sound waves of the cone speaker (15) are directed toward the air intake pipe (8). A vertical first sound-transmitting protective tube (17) is fixedly arranged on the air intake pipe (8). The lower end of the first sound-transmitting protective tube (17) penetrates into the air intake pipe (8), and the first microphone (14) is fixedly arranged in the first sound-transmitting protective tube (17).

3. The active noise reduction composite muffler according to claim 1, characterized in that: The secondary noise reduction mechanism includes a second microphone (18) and a dome-shaped speaker (19). An air collecting pipe (20) and a sound-transmitting shield (21) are fixedly provided on two partitions (2) adjacent to the tail noise reduction chamber (6), respectively. The air collecting pipe (20) is connected to the corresponding vent (9). A vertical second sound-transmitting shield (22) is fixedly provided in the air collecting pipe (20). The lower end of the second sound-transmitting shield (22) penetrates into the air collecting pipe (20). The second microphone (18) is fixedly provided in the second sound-transmitting shield (22). The dome-shaped speaker (19) is fixed in the sound-transmitting shield (21), and the sound waves of the dome-shaped speaker (19) are directed toward the air collecting pipe (20).

4. The active noise reduction composite muffler according to claim 1, characterized in that: The housing shell (1) is in the shape of a curved rectangle, and the end edge of the housing shell (1) is formed by an arc-shaped surface (23). Each partition (2) is rectangular, and both ends of each partition (2) are formed with a round head (24) that fits the arc-shaped surface (23). The vent hole (9) is close to the round head (24) of the partition (2), and adjacent vent holes (9) are staggered.

5. The active noise reduction composite muffler according to claim 1, characterized in that: The exhaust pipe No. 1 (11) includes a straight pipe No. 1 (25), a curved pipe No. 1 (26) and a tail pipe No. 1 (27). The straight pipe No. 1 (25) is horizontally arranged in the housing (1). The straight pipe No. 1 (25) passes through a plurality of partitions (2) in sequence. The two ends of the straight pipe No. 1 (25) are respectively located in the pressure relief chamber (3) and the cavity (7). The tail pipe No. 1 (27) is parallel to the straight pipe No. 1 (25). The tail pipe No. 1 (27) is arranged outside the housing (1). The curved pipe No. 1 (26) connects one end of the straight pipe No. 1 (25) located in the cavity (7) to the tail pipe No. 1 (27).

6. The active noise reduction composite muffler according to claim 5, characterized in that: The No. 2 exhaust pipe (12) includes a No. 2 straight pipe (28), a No. 2 curved pipe (29) and a No. 2 tail pipe (30). The No. 2 straight pipe (28) is arranged below the No. 1 straight pipe (25) and is parallel to the No. 1 straight pipe (25). The No. 2 straight pipe (28) passes through a plurality of partitions (2) in sequence. The two ends of the No. 2 straight pipe (28) are respectively located in the pressure relief chamber (3) and the tail noise reduction chamber (6). The No. 2 tail pipe (30) is parallel to the No. 1 tail pipe (27). The No. 2 tail pipe (30) is arranged outside the housing (1). The No. 2 curved pipe (29) connects one end of the No. 2 straight pipe (28) located in the pressure relief chamber (3) to the No. 2 tail pipe (30).

7. The active noise reduction composite muffler according to claim 6, characterized in that: The perforated passive silencer mechanism (13) includes a silencer drum (31), a rotary drive member, and a silencer sleeve (32). The number of expansion chambers (5) is several. The portions where the No. 1 straight pipe (25) and the No. 2 straight pipe (28) pass through the expansion chamber (5) are silencer sections (33). The silencer sections (33) are provided with several groups of No. 1 silencer holes (34) equidistantly distributed along their axial directions. Each group of No. 1 silencer holes (34) is in a circumferential array. The silencer drum (31) is rotatably sleeved on the corresponding silencer section (33). The silencer drum (31) is provided with several groups of No. 2 silencer holes (35) equidistantly distributed along their axial directions. Each group of No. 2 silencer holes (35) is in a circumferential array. The silencer sleeve (32) is sleeved on the corresponding silencer drum (31). The rotary drive member is used to synchronously drive the several silencer drums (31) to rotate.

8. The active noise reduction composite muffler according to claim 7, characterized in that: Both ends of the muffler drum (31) are coaxially formed with columnar expansion sleeves (36), and a bearing (37) is provided between the columnar expansion sleeve (36) and the muffler section (33).

9. The active noise reduction composite muffler according to claim 7, characterized in that: The rotary drive member includes a first gear ring (38), a second gear ring (39), a gear (40) and a drive shaft (41). The first gear ring (38) and the second gear ring (39) are coaxially fixedly connected to the muffler drum (31) on the first straight tube (25) and the second straight tube (28), respectively, and the first gear ring (38) is meshed with the second gear ring (39). A mounting shell (42) is fixedly provided at the bottom of the accommodating shell (1). The mounting shell (42) is connected to the corresponding expansion chamber (5). The gear (40) is rotatably arranged in the mounting shell (42), and the gear (40) is meshed with the second gear ring (39). The drive shaft (41) is horizontally arranged at the bottom of the accommodating shell (1). The drive shaft (41) coaxially fixes the plurality of gears (40).

10. The active noise reduction composite muffler according to claim 1, characterized in that: The high-pressure pneumatic valve (10) includes a connecting seat (43), a valve plate (44), a sealing plate (45) and a plurality of springs (46). The connecting seat (43) is arranged in the head noise reduction chamber (4), and the connecting seat (43) is fixedly connected to the adjacent partition (2). An accommodating chamber (47) is provided in the connecting seat (43). The valve plate (44) is vertically arranged to cover the accommodating chamber (47). The valve plate (44) is formed with a plurality of springs (46) connected to the connecting seat (43). A sliding rod (48) is slidably connected, and each spring (46) is sleeved on the sliding rod (48). The valve plate (44) presses the spring (46) into the accommodating chamber (47). A limit nut (49) is screwed on the end of the sliding rod (48). A pressure relief port (50) is opened on the partition (2) located next to the pressure relief chamber (3). The sealing plate (45) is fixedly connected to the valve plate (44), and the sealing plate (45) blocks the pressure relief port (50).

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