Exhaust silencing system

Abstract

The invention relates to the field of silencers, and discloses an exhaust silencing system which comprises a first silencer, a second silencer and a third silencer which are sequentially connected in series. The first silencer comprises a first resonant cavity and a first filling cavity which are sequentially arranged in the airflow direction, and the first resonant cavity is configured to attenuate noise of a first target frequency band; the second silencer comprises a second resonant cavity and a second filling cavity, and the second resonant cavity is configured to attenuate noise of a second target frequency band; the third silencer comprises a resistant silencing cavity and a third filling cavity, and the resistant silencing cavity is configured to attenuate noise of a third target frequency band; the first filling cavity, the second filling cavity and the third filling cavity are filled with sound absorption materials, and any two of the first target frequency band, the second target frequency band and the third target frequency band at least comprise different frequency ranges. According to the exhaust and noise elimination system, the exhaust and noise elimination system is connected in series in structure and complementary in acoustic function, and a full-band coverage noise attenuation path with complementary frequency bands is jointly formed.

Description

Technical Field

[0001] This invention relates to the field of muffler technology, and more specifically to an exhaust muffler system. Background Technology

[0002] As an emerging clean energy technology, hydrogen fuel cells generate airflow noise with a wide frequency spectrum and high sound pressure level during operation, especially under high flow conditions. This noise has a broad frequency band, covering a wide range from low to high frequencies.

[0003] Currently, existing silencer structures have good suppression effects on mid-to-low frequency noise, but their performance is insufficient in the high-frequency range; while other structures can effectively handle high-frequency noise, their attenuation capability for low-frequency components is limited. In addition, if a single broadband silencer structure is used, it is often difficult to achieve a balanced and efficient silencer effect across the entire target frequency band.

[0004] Therefore, a single silencing structure or a simple combination of structures cannot achieve efficient, balanced, and low-resistance comprehensive suppression of wide-band exhaust noise, resulting in poor overall silencing effect and easily increasing system size and resistance. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing an exhaust noise reduction system that solves the problems of existing fuel cell mufflers, such as inefficient coverage of noise across the entire frequency band, uneven noise reduction effects across different frequency bands, and structural redundancy. This system achieves stepped noise reduction across the entire frequency band from low to high frequencies.

[0006] To achieve the above objectives, the present invention provides an exhaust silencing system, comprising: a first silencer, a second silencer, and a third silencer connected in series; the first silencer includes a first resonant cavity and a first filling cavity arranged sequentially along the airflow direction, the first resonant cavity being configured to attenuate noise in a first target frequency band; the second silencer includes a second resonant cavity and a second filling cavity arranged sequentially along the airflow direction, the second resonant cavity being configured to attenuate noise in a second target frequency band; the third silencer includes a reactive silencing cavity and a third filling cavity arranged sequentially along the airflow direction, the reactive silencing cavity being configured to attenuate noise in a third target frequency band; the first filling cavity, the second filling cavity, and the third filling cavity are all filled with sound-absorbing material, and any two of the first target frequency band, the second target frequency band, and the third target frequency band include at least different frequency ranges.

[0007] The advantages of the exhaust muffler system compared to existing technologies lie in the fact that the first, second, and third mufflers allocate different target frequency bands for low-mid frequency, mid-frequency, and broadband noise, respectively. They are connected in series structurally and complementary in acoustic function, collectively forming a complementary, full-band noise attenuation path. This synergistic system effectively overcomes the limitations of single muffler structures, such as narrow bandwidth and low efficiency, achieving a balance of high acoustic performance, low flow resistance, and high compactness within a limited layout space.

[0008] According to some embodiments of the present invention, the first muffler includes: a first muffler pipe, a first end of which is connected to the intake pipe of an exhaust system, and a second end of which is connected to the second muffler; a first housing, which is sleeved on the outside of the first muffler pipe and together with the first muffler pipe defines a first silencing cavity; a first partition, which is disposed inside the first housing to divide the first silencing cavity into a first resonant cavity and a first filling cavity; a first airflow hole is formed on the peripheral wall of the first muffler pipe at a pipe segment position corresponding to the first resonant cavity, and a first airflow hole is formed on the peripheral wall of the first muffler pipe at a pipe segment position corresponding to the first filling cavity; a second partition, which is disposed inside the first housing and located inside the first resonant cavity to divide the first resonant cavity into a first sub-cavity and a second sub-cavity, and a second end of the first muffler pipe sequentially passes through the first partition and the second partition and extends out of the first housing.

[0009] According to some embodiments of the present invention, the first target frequency band is configured to attenuate low-frequency noise, the first sub-cavity is used to attenuate low-frequency noise, and the second sub-cavity is used to attenuate mid-frequency noise.

[0010] According to some embodiments of the present invention, the bottom of the first partition and the second partition are provided with a drainage groove, and the first housing is provided with a drain outlet communicating with the drainage groove.

[0011] According to some embodiments of the present invention, the second muffler includes: a second muffler pipe, the first end of which is connected to the first muffler, and the second end of which is connected to the third muffler; a second housing, which is sleeved outside the second muffler pipe and together with the second muffler pipe defines a second silencing cavity; a third partition, which is disposed inside the second housing to divide the second silencing cavity into a second resonant cavity and a second filling cavity, and second airflow holes are provided on the peripheral wall of the second muffler pipe at pipe segments corresponding to the positions of the second resonant cavity and the second filling cavity.

[0012] According to some embodiments of the present invention, the second target frequency band is configured to attenuate intermediate frequency noise.

[0013] According to some embodiments of the present invention, a drainage groove is provided at the bottom of the third partition, and a drain outlet communicating with the drainage groove is provided on the second housing.

[0014] According to some embodiments of the present invention, the third muffler includes: a third housing; a first baffle disposed within the third housing to divide the third housing into the resistive muffler cavity and the third filling cavity; a second baffle disposed within the third housing and located within the resistive muffler cavity, the second baffle having a perforation; a third muffler pipe, the first end of the third muffler pipe communicating with the second muffler, the second end of the third muffler pipe penetrating through the second baffle, the peripheral wall of the third muffler pipe having a third airflow hole at a pipe segment position corresponding to the resistive muffler cavity; a fourth muffler pipe, the first end of the fourth muffler pipe located within the resistive muffler cavity, the second end of the fourth muffler pipe communicating with the exhaust tailpipe of the exhaust system, the peripheral wall of the fourth muffler pipe having a fourth airflow hole at a pipe segment position corresponding to the third filling cavity; the axes of the third muffler pipe and the fourth muffler pipe are parallel and spaced apart, and along the airflow direction, the second end of the third muffler pipe and the first end of the fourth muffler pipe are spaced apart.

[0015] According to some embodiments of the present invention, the bottom of the first baffle and / or the second baffle is provided with a drainage groove, and the third housing is provided with a drain outlet communicating with the drainage groove.

[0016] According to some embodiments of the present invention, the volumes of the first filling cavity, the second filling cavity, and the third filling cavity are different.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present application. Attached Figure Description

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the overall structure of the exhaust muffler system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the first muffler according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the second muffler according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the third muffler according to an embodiment of the present invention.

[0019] Figure label: 100. Exhaust silencing system; 101. First resonant cavity; 1011. First sub-cavity; 1012. Second sub-cavity; 102. First filling cavity; 103. Second resonant cavity; 104. Second filling cavity; 105. Resistant silencing cavity; 1051. First chamber; 1052. Second chamber; 106. Third filling cavity; 10. First silencer; 11. First silencer pipe; 12. First housing; 13. First partition plate; 14. Second partition plate; 15. First airflow hole; 20. Second silencer; 21. Second silencer pipe; 22. Second housing; 23. Third baffle; 24. Second airflow hole; 30. Third silencer; 31. Third housing; 32. First baffle; 33. Second baffle; 331. Perforation; 34. Third silencer pipe; 35. Fourth silencer pipe; 36. Third airflow hole; 37. Fourth airflow hole; 40. Connecting pipe; 41. First connecting pipe; 42. Second connecting pipe. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] The following is for reference. Figures 1 to 4 An exhaust muffler system according to an embodiment of the present invention is described.

[0022] According to an embodiment of the present invention, the exhaust silencing system 100 includes a first silencer 10, a second silencer 20 and a third silencer 30 connected in series along the airflow direction. The first silencer 10, the second silencer 20 and the third silencer 30 are designed specifically for noise in a specific frequency band, thus forming a multi-stage coordinated silencing system.

[0023] Specifically, the first silencer 10 includes a first resonant cavity 101 and a first filling cavity 102 arranged sequentially along the airflow direction. The first resonant cavity 101 is configured to attenuate noise in a first target frequency band, which is mid-to-low frequency noise with a frequency range of 400Hz to 700Hz. Specifically, the first resonant cavity 101, as a reactive noise reduction unit, is configured to specifically and efficiently attenuate mid-to-low frequency noise in the 400-700Hz range based on the Helmholtz resonance principle. The first filling cavity 102, adjacent to the first resonant cavity 101, is a resistive noise reduction unit, filled with high-temperature resistant sound-absorbing material, mainly acting on mid-to-high frequency noise above 1500Hz, achieving effective attenuation by converting sound energy into heat energy.

[0024] The second silencer 20 is connected in series downstream of the first silencer 10. The second silencer 20 includes a second resonant cavity 103 and a second filling cavity 104 arranged sequentially along the airflow direction. The second resonant cavity 103 is configured to attenuate noise in a second target frequency band. The second resonant cavity 103 is also based on the Helmholtz resonance principle, but its second target frequency band is mid-frequency noise, with a frequency range of approximately 1100Hz. This fills the processing gap of the first silencer 10 in this frequency band. The second filling cavity 104 further enhances the resistive noise attenuation effect on residual mid-to-high frequency noise. The second filling cavity 104 is also filled with sound-absorbing material, mainly targeting mid-to-high frequency noise above 1500Hz.

[0025] The third silencer 30 is located at the end of the system. The third silencer 30 includes a reactive anechoic cavity 105 and a third filling cavity 106 arranged sequentially along the airflow direction. The reactive anechoic cavity 105 is configured to attenuate noise in a third target frequency band, which can be broadband noise. The first, second, and third target frequency bands each include at least two different frequency ranges, thus achieving acoustic complementarity. Through structural series connection, they together form a complementary full-band noise attenuation path. The reactive anechoic cavity 105 uses a perforated plate or similar structure to create an impedance abrupt change, supplementing the suppression of broadband noise (especially frequency bands not fully covered by the first and second silencers 10 and 20). The third filling cavity 106 at the end serves as the final interception unit, ensuring the absorption of residual noise across the entire frequency band, particularly in the mid-to-high frequency range.

[0026] The exhaust muffler system 100 according to an embodiment of the present invention allocates different target frequency bands for low-mid frequency, mid-frequency, and broadband noise through a first muffler 10, a second muffler 20, and a third muffler 30, respectively. These components are connected in series structurally and complementary in acoustic function, collectively forming a complementary, full-band noise attenuation path. This collaborative system effectively overcomes the limitations of single muffler structures, such as narrow bandwidth and low efficiency, achieving a balance of high acoustic performance, low flow resistance, and high compactness within a limited layout space.

[0027] It should be noted that the "full-band" proposed in the embodiments of this invention does not include all frequency bands, but rather refers to a complete and continuous broadband noise obtained based on actual measurements and analysis of the exhaust noise spectrum of a typical hydrogen fuel cell. This invention utilizes a specific resonant cavity, reactive silencing structure, and resistive filling cavity in a synergistic combination at specific frequency bands to decompose the frequency band silencing target into multiple specific, achievable, and interconnected sub-targets, thereby ensuring efficient and balanced suppression of broadband noise from 20Hz to 3000Hz.

[0028] In some embodiments, refer to Figure 2 The first muffler 10 includes a first muffler pipe 11, a first housing 12, a first partition 13, and a second partition 14. The first muffler pipe 11 extends along the airflow direction. The first end of the first muffler pipe 11 is connected to the intake pipe of the exhaust system to introduce exhaust gas, and the second end of the first muffler pipe 11 is connected to the second muffler 20, thereby establishing a continuous silencing flow path. Specifically, the second end of the first muffler pipe 11 can be connected to the second muffler 20 through a first connecting pipe 41. The first housing 12 is fitted outside the first muffler pipe 11 and together with the first muffler pipe 11 defines a first silencing cavity. To achieve more precise frequency band control, the first partition 13 is disposed inside the first housing 12 to divide the first silencing cavity into a first resonant cavity 101 and a first filling cavity 102. The second partition 14 is disposed within the first housing 12 and located within the first resonant cavity 101, dividing the first resonant cavity 101 into a first sub-cavity 1011 and a second sub-cavity 1012. By precisely designing the volume and structural parameters of the first sub-cavity 1011 and the second sub-cavity 1012, they can be tuned to different resonant frequencies respectively. Along the airflow direction, the second partition 14 is located upstream, and the first partition 13 is located downstream. Neither the first partition 13 nor the second partition 14 has any openings. On the peripheral wall of the first silencer pipe 11, a first airflow hole 15 is provided corresponding to the pipe section position of the first resonant cavity 101; a first airflow hole 15 is also provided on the peripheral wall of the first silencer pipe 11, corresponding to the pipe section position of the first filling cavity 102, to realize the interaction of airflow between the first silencer pipe 11 and the first resonant cavity 101 and the first filling cavity 102. The number of first airflow holes corresponding to the pipe segment positions of the first resonant cavity 101 can be multiple, and the number of first airflow holes corresponding to the pipe segment positions of the first filling cavity 102 can also be multiple, thereby improving the noise reduction effect. Preferably, the multiple first airflow holes at each pipe segment position are evenly distributed along the peripheral wall of the first silencer pipe 11. The second end of the first silencer pipe 11 passes through the second partition 14 and the first partition 13 in sequence, and extends out of the first housing 12.

[0029] In some embodiments, refer to Figure 2 The first target frequency band is configured to attenuate low- and mid-frequency noise. The first sub-cavity 1011 is used to attenuate low-frequency noise, and the second sub-cavity 1012 is used to attenuate mid-frequency noise. Specifically, the first sub-cavity 1011 is for 400Hz, and the second sub-cavity 1012 is for 700Hz. Based on the Helmholtz principle, it performs targeted and efficient absorption or attenuation of specific low- and mid-frequency noise.

[0030] In this embodiment of the invention, reference is made to Figure 2The first resonant cavity 101 serves as reactive noise reduction, and the first filling cavity 102 serves as resistive noise reduction. By organically combining reactive and resistive noise reduction within the first housing 12, and through the synergistic effect of resonant absorption and broadband resistive filtering, efficient processing of mid-low and mid-high frequency noise is achieved under the premise of compact structure.

[0031] In some embodiments, refer to Figure 2 The first airflow holes 15 on the peripheral wall of the first silencer 11 are designed with a non-uniform distribution, which matches the airflow velocity and acoustic treatment requirements. Along the airflow direction, the distribution density of the first airflow holes 15 on the peripheral wall of the first silencer 11 is distributed according to the intervals of the pipe segments corresponding to each chamber, and increases in a gradient. Specifically, on the peripheral wall of the first silencer 11, the number of first airflow holes 15 set in the pipe segment corresponding to the first sub-cavity 1011 is less than the number of first airflow holes 15 set in the pipe segment corresponding to the second sub-cavity 1012, and the number of first airflow holes 15 set in the pipe segment corresponding to the first filling cavity 102 is greater than the number of first airflow holes 15 set in the pipe segment corresponding to the second sub-cavity 1012. Fewer holes are opened in the first sub-cavity 1011 region at the air inlet end to maintain sufficient back pressure and resonance effect; denser holes are opened in the first filling cavity 102 region near the outlet to fully reduce pressure and guide the airflow to interact with the sound-absorbing material, thereby achieving efficient dissipation of sound energy.

[0032] In some embodiments, refer to Figure 2 The bottom of the first partition 13 and the second partition 14 are provided with drainage channels, and the first housing 12 is provided with a drain outlet. The drainage channels are connected to the drain outlet. When the water-rich exhaust gas condenses in the first resonant cavity 101, the droplets impact the first partition 13 and the second partition 14 and flow along the wall surface, eventually collecting in the drainage channel and being smoothly discharged to the outside of the system through the drain outlet. This effectively prevents internal water accumulation, avoids the decrease in sound absorption performance and component corrosion caused by liquid accumulation, and thus ensures the long-term working stability and durability of the sound absorption system.

[0033] In some embodiments, refer to Figure 3The second silencer 20 includes a second silencer pipe 21, a second housing 22, and a third partition 23. The second silencer pipe 21 extends along the airflow direction. The first end of the second silencer pipe 21 is connected to the outlet of the first silencer 10 via a first connecting pipe 41, and the second end of the second silencer pipe 21 is connected to the third silencer 30, forming a downstream silencing path. The second housing 22 is fitted over the second silencer pipe 21 and together with the second silencer pipe 21 defines a second silencing cavity. The third partition 23 is disposed inside the second housing 22 to divide the second silencing cavity into a second resonant cavity 103 and a second filling cavity 104. The third partition 23 is not perforated. Second airflow holes 24 are provided on the peripheral wall of the second silencer pipe 21 at positions corresponding to the pipe segments of the second resonant cavity 103 and the second filling cavity 104, to facilitate airflow exchange and noise reduction between the second silencer pipe 21 and the corresponding cavities. Specifically, there can be multiple second airflow holes, evenly distributed on the peripheral wall of the second silencer pipe 21.

[0034] In some embodiments, refer to Figure 3 The second airflow holes 24 on the periphery of the second silencer 21 are designed with a non-uniform distribution, and their distribution is adapted to the acoustic and hydrodynamic characteristics inside the second silencer 20.

[0035] Specifically, the axial length of the second resonant cavity 103 is less than the axial length of the second filling cavity 104. Based on this structure, the distribution density of the second airflow holes 24 on the peripheral wall of the second silencer 21 is coordinated with the length and function of the corresponding chamber. On the pipe segment corresponding to the shorter axial length of the second resonant cavity 103, the number of second airflow holes 24 is relatively small, which helps to maintain the necessary airflow velocity and pressure within the second resonant cavity 103, ensuring effective resonance attenuation of specific mid-frequency noise (such as 1100Hz).

[0036] In some embodiments, refer to Figure 3 The second target frequency band is configured to attenuate intermediate frequency noise. Specifically, the structural parameters of the second resonant cavity 103 are matched with the intermediate frequency noise resonant frequency of about 1100Hz to specifically suppress noise in this frequency band.

[0037] In some embodiments, refer to Figure 3 The bottom of the third partition 23 is provided with a drainage groove, and the second housing 22 is provided with a drain outlet that communicates with the drainage groove. When liquid water or condensate carried by the airflow enters the second silencer 20, it will impact the surface of the third partition 23 and flow down the wall, eventually collecting in the drainage groove at the bottom and being smoothly discharged from the system through the drain outlet, further ensuring the reliability and durability of the second silencer 20.

[0038] In some embodiments, refer to Figure 4The third silencer 30 includes a third housing 31, a first baffle 32, a second baffle 33, a third silencer pipe 34, and a fourth silencer pipe 35. The first baffle 32 is disposed within the third housing 31 to divide the interior of the third housing 31 into a reactive silencer cavity 105 and a third filling cavity 106. The second baffle 33 is disposed within the third housing 31 and within the reactive silencer cavity 105, and has perforations 331, the number of which can be multiple. These perforations 331 are evenly distributed on the second baffle 33. The first end of the third silencer pipe 34 is connected to the second silencer 20 via a second connecting pipe 42, and the second end of the third silencer pipe 34 penetrates the second baffle 33, together forming a perforated plate assembly structure, creating a plug structure. This structure, by creating a sudden change in acoustic impedance, effectively assists in suppressing noise across the entire frequency band, especially the remaining frequency bands not fully covered by the first silencer 10 and the second silencer 20. On the peripheral wall of the third silencer pipe 34, a third airflow hole 36 is provided corresponding to the pipe segment position of the resistive silencer cavity 105. Multiple third airflow holes 36 are evenly distributed on the peripheral wall of the third silencer pipe 34. Specifically, the third silencer pipe 34 passes through the second baffle 33, which divides the resistive silencer cavity 105 into a first chamber 1051 and a second chamber 1052 along the airflow direction. The axial length of the first chamber 1051 can be less than the axial length of the second chamber 1052. Furthermore, on the peripheral wall of the third silencer pipe 34, the number of third airflow holes 36 provided at the pipe segment position corresponding to the first chamber 1051 is less than the number of third airflow holes 36 provided at the pipe segment position corresponding to the second chamber 1052. The first end of the fourth muffler 35 is located inside the resistive muffler cavity 105, and the second end of the fourth muffler 35 is connected to the exhaust tailpipe of the exhaust system. A fourth airflow hole 37 is provided on the peripheral wall of the fourth muffler 35 at a position corresponding to the pipe section of the third filling cavity 106. There are multiple fourth airflow holes 37. The axes of the third muffler 34 and the fourth muffler 35 are parallel and spaced apart; that is, the axis of the third muffler 34 and the axis of the fourth muffler 35 are spaced apart. On the projection plane of the end face of the third housing 31, the third muffler 34 and the fourth muffler 35 are staggered but may partially overlap. Along the airflow direction, the second end of the third muffler 34 and the first end of the fourth muffler 35 are spaced apart. For example, the second end of the third silencer 34 is located in the second chamber 1052, the first end of the fourth silencer 35 is located in the second chamber 1052, and the second end of the third silencer 34 has a first gap with the first baffle 32, and the first end of the fourth silencer 35 has a second gap with the first baffle 32, the first gap being longer than the length of the second gap.

[0039] After entering from the first end of the third silencer 34, the airflow undergoes multiple splits and energy dissipation within the resistive anechoic chamber 105. Specifically, a portion of the airflow exits through the third airflow hole 36 on the section of the third silencer 34 located on the side of the second baffle 33 furthest from the first baffle 32, before reaching the second baffle 33. This portion of the airflow passes directly through the perforation 331 on the second baffle 33 and flows into the space on the side closer to the first baffle 32. Another portion of the airflow continues along the third silencer 34 and exits directly into the chamber on the side of the second baffle 33 closest to the first baffle 32 from its second end outlet. A further portion of the airflow exits through the third airflow hole 36 on the section of the third silencer 34 located on the side of the second baffle 33 closest to the first baffle 32. After completing this complex multi-path diffusion, all the airflow entering the resistive anechoic chamber 105 is thoroughly mixed and expands and decelerates due to the drastic change in the chamber's cross-section. During this process, sound waves interfere and reflect, and sound energy is significantly dissipated. Finally, the airflow converges and enters through the first end of the fourth silencer 35, then enters the final processing stage through the fourth airflow hole 37 on its wall corresponding to the third filling cavity 106. Inside the third filling cavity 106, the airflow comes into full contact with the sound-absorbing material, where high-frequency sound waves are converted into heat energy due to friction, achieving efficient absorption of residual mid-to-high frequency noise, and finally discharged through the exhaust tailpipe.

[0040] In this embodiment, refer to Figure 4 By connecting the reactive anechoic cavity 105 and the third filling cavity 106 in series, and combining the multi-path airflow design within the cavity, supplementary suppression of broadband noise (especially the frequency band not fully processed by the pre-stage) and final interception of mid-to-high frequency noise are achieved, ensuring a full-band noise reduction effect. The plug structure forces the airflow to undergo more complex expansion, contraction, diffraction, and reflection processes within the reactive anechoic cavity 105, greatly increasing the number of sound wave interferences and reflections, thereby significantly improving the dissipation efficiency of the reactive anechoic unit for low-frequency and some mid-frequency noise.

[0041] In some embodiments, refer to Figure 4 The bottom of the first baffle 32 and / or the second baffle 33 is provided with a drainage groove, and the third housing 31 is provided with a drain outlet. The drainage groove and the drain outlet are connected. This arrangement is conducive to draining accumulated water, thereby preventing the attenuation of sound absorption performance caused by liquid accumulation.

[0042] In some embodiments, refer to Figures 1 to 4In the exhaust muffler system 100, a first muffler 10, a second muffler 20, and a third muffler 30 are connected in sequence. The system's intake air enters through the inlet of the first muffler 10 and flows sequentially through the first muffler 10, the second muffler 20, and the third muffler 30, finally exiting through the outlet of the third muffler 30 via the exhaust tailpipe. The first end of the first muffler 10 is the inlet, and the second end of the third muffler 30 is the outlet. The connecting pipe 40 includes a first connecting pipe 41 and a second connecting pipe 42.

[0043] Specifically, the intake pipe of the exhaust system is connected to the first end of the first muffler pipe 11 of the first muffler 10; the second end of the first muffler pipe 11 is connected to the first end of the first connecting pipe 41; the second end of the first connecting pipe 41 is connected to the first end of the second muffler pipe 21 of the second muffler 20; the second end of the second muffler pipe 21 is connected to the first end of the second connecting pipe 42; the second end of the second connecting pipe 42 is connected to the first end of the third muffler pipe 34 of the third muffler 30; and the second end of the fourth muffler pipe 35 of the third muffler 30 is connected to the exhaust tailpipe of the exhaust system. By connecting the complementary first muffler 10, second muffler 20, and third muffler 30 in series, the noise in the exhaust gas undergoes a multi-stage, orderly, stepped attenuation process. The airflow first undergoes preliminary treatment of low-to-mid-frequency noise in the first muffler 10, then fills the processing gap in the mid-frequency range in the second muffler 20, and finally performs deep interception and final treatment of broadband residual noise in the third muffler 30.

[0044] In some embodiments, refer to Figures 2 to 4 The first filling cavity 102, the second filling cavity 104 and the third filling cavity 106 have different volumes, which allows for precise configuration of the amount of cotton filling in the first filling cavity 102, the second filling cavity 104 and the third filling cavity 106 to achieve gradual absorption of mid-to-high frequency noise, avoid insufficient efficiency or excessive resistance caused by a single amount of cotton filling, and thus maintain a low exhaust back pressure of the system while ensuring efficient wideband noise reduction.

[0045] In a specific example, the amount of sound-absorbing material filling the first filling cavity 102, the second filling cavity 104, and the third filling cavity 106 is 60 grams, 200 grams, and 150 grams, respectively. Specifically, the sound-absorbing material can be sound-absorbing cotton. The second filling cavity 104 serves as the main resistive noise reduction zone, utilizing a larger amount of cotton to concentrate and effectively absorb mid-to-high frequency noise. The first filling cavity 102 and the third filling cavity 106 are located before and after the second filling cavity 104, respectively. The first filling cavity 102 acts as a pre-treatment layer, while the third filling cavity 106 acts as the final interception layer, together forming a sound energy dissipation path to achieve efficient reduction of mid-to-high frequency noise.

[0046] In this specification, unless otherwise stated, for all types of pipes involved in the exhaust muffler system 100, "first end" refers to the end located upstream in the normal operating airflow direction, i.e., the intake end; and "second end" refers to the end located downstream, i.e., the outlet end. This definition applies to all pipe components such as the first muffler pipe 11 and the second muffler pipe 21.

[0047] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one embodiment or example.

[0048] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An exhaust muffler system, characterized in that, include: The first muffler, the second muffler, and the third muffler are connected in series. The first silencer includes a first resonant cavity and a first filling cavity arranged sequentially along the airflow direction, and the first resonant cavity is configured to attenuate noise in a first target frequency band; The second silencer includes a second resonant cavity and a second filling cavity arranged sequentially along the airflow direction, wherein the second resonant cavity is configured to attenuate noise in the second target frequency band; The third silencer includes a reactive silencing cavity and a third filling cavity arranged sequentially along the airflow direction. The reactive silencing cavity is configured to attenuate noise in the third target frequency band. The first filling cavity, the second filling cavity, and the third filling cavity are all filled with sound-absorbing material, and any two of the first target frequency band, the second target frequency band, and the third target frequency band include at least different frequency ranges.

2. The exhaust muffler system according to claim 1, characterized in that, The first muffler includes: The first muffler pipe has a first end connected to the intake pipe of the exhaust system and a second end connected to the second muffler. A first housing is sleeved outside the first silencer pipe and together with the first silencer pipe defines a first silencing cavity; A first partition plate is disposed inside the first housing to divide the first silencing cavity into the first resonant cavity and the first filling cavity; a first airflow hole is provided on the peripheral wall of the first silencing pipe and at the pipe segment position corresponding to the first resonant cavity; a first airflow hole is provided on the peripheral wall of the first silencing pipe and at the pipe segment position corresponding to the first filling cavity. The second partition is disposed inside the first housing and located inside the first resonant cavity to divide the first resonant cavity into a first sub-cavity and a second sub-cavity. The second end of the first silencer tube passes through the first partition and the second partition in sequence and extends out of the first housing.

3. The exhaust muffler system according to claim 2, characterized in that, The first target frequency band is configured to attenuate low-frequency noise, the first sub-cavity is used to attenuate low-frequency noise, and the second sub-cavity is used to attenuate mid-frequency noise.

4. The exhaust muffler system according to claim 2, characterized in that, The bottom of the first partition and the second partition are provided with drainage grooves, and the first housing is provided with a drain outlet that communicates with the drainage grooves.

5. The exhaust muffler system according to claim 1, characterized in that, The second muffler includes: The second muffler has a first end connected to the first muffler and a second end connected to the third muffler. The second housing is sleeved outside the second silencer pipe and together with the second silencer pipe defines the second silencer cavity; The third partition is disposed inside the second housing to divide the second silencing cavity into the second resonant cavity and the second filling cavity; on the peripheral wall of the second silencing pipe, a second airflow hole is provided at the pipe section position corresponding to the second resonant cavity and the second filling cavity.

6. The exhaust muffler system according to claim 5, characterized in that, The second target frequency band is configured to attenuate intermediate frequency noise.

7. The exhaust muffler system according to claim 5, characterized in that, The bottom of the third partition is provided with a drainage groove, and the second housing is provided with a drain outlet that communicates with the drainage groove.

8. The exhaust muffler system according to claim 1, characterized in that, The third silencer includes: Third shell; A first baffle is disposed inside the third housing to divide the third housing into the resistive sound-absorbing cavity and the third filling cavity; The second baffle is disposed in the third housing and located in the resistant silencing cavity, and the second baffle has a perforation. The third silencer pipe has a first end connected to the second silencer, and a second end of the third silencer pipe penetrates the second baffle. A third airflow hole is provided on the peripheral wall of the third silencer pipe at the pipe section position corresponding to the resistive silencer cavity. The fourth muffler has a first end located inside the resistive muffler cavity, and a second end connected to the exhaust tailpipe of the exhaust system. A fourth airflow hole is provided on the peripheral wall of the fourth muffler at a position corresponding to the pipe section of the third filling cavity. The axes of the third and fourth silencers are parallel and spaced apart. Along the airflow direction, the second end of the third silencer is spaced apart from the first end of the fourth silencer.

9. The exhaust muffler system according to claim 8, characterized in that, The bottom of the first baffle and / or the second baffle is provided with a drainage groove, and the third housing is provided with a drain outlet communicating with the drainage groove.

10. The exhaust muffler system according to claim 1, characterized in that, The volumes of the first filling cavity, the second filling cavity, and the third filling cavity are different.

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