Standard silencer structure and silencing performance database rapid establishment method thereof

Abstract

The invention discloses a standard silencer structure and a rapid building method of a silencing performance database of the standard silencer structure, the structure is composed of an upper shell, a lower shell, an inner core framework and a perforated plate, and the inner core framework, the upper shell, the lower shell and the perforated plate are mutually clamped to form a main pipeline and a silencing cavity. Compared with the prior art, according to the scheme, the upper shell, the lower shell, the inner core framework and the perforated plate of the structure are repeatedly used, the silencing characteristics of many silencers can be obtained through measurement of few real objects, operation is easy, the sample piece utilization rate is high, and the silencing performance database of the standard silencer built through the method has the advantages of being high in practicability and the like. A traditional theoretical formula can be replaced in the development of the broadband silencer, the scheme design of the silencer is guided, and a design scheme meeting a performance target can be obtained only by tuning for several times; reference can be provided for sample piece modification in later-stage real vehicle tuning, the number of trial and error times is reduced, the development period is shortened, and the development cost is saved.

Description

Technical Field

[0001] The invention relates to the technical field of mufflers, and in particular to a standard muffler structure and a method for quickly establishing a muffler performance database thereof. Background Art

[0002] Intake system noise is one of the main noise sources of automobiles. Naturally aspirated engines are subject to speed limits, and the frequency of the intake noise generated is mainly distributed below 1000Hz; due to the high speed operation of the compressor impeller of a supercharged engine, a high-frequency howling sound will be generated when the supercharger exhaust valve is opened, making the intake noise frequency reach above 5000Hz. In view of the noise characteristics of turbocharged engines, perforated tube mufflers with higher silencing frequencies are widely used. The perforated tube muffler is a resonant muffler that uses the principle of the Helmholtz muffler to filter sound waves. In applications, multiple perforated tube mufflers are usually connected in series to form a broadband muffler.

[0003] Under the existing technical route, when designing and developing broadband mufflers, the initial muffler scheme is generally calculated according to the theoretical formula, and then the simulation method is used to repeatedly tune the sound and optimize the muffler structural parameters to ensure that the design scheme meets the performance target. During the development process, the theoretical formula has low calculation accuracy, and it is difficult to obtain effective references from the existing broadband muffler database during the scheme design and tuning process, resulting in a long development cycle. The muffler scheme calculated according to the theoretical formula has a large deviation from the theoretical muffler characteristics, especially in the high frequency band, the error can exceed 50%, because the Helmholtz muffler theoretical formula cannot consider the mass distribution and sound wave movement in the connecting pipe and the resonance cavity. The existing broadband muffler muffler performance database consists of the transmission loss curves of broadband mufflers of various models. These transmission loss curves contain the muffler characteristics of the entire broadband muffler, but due to the mutual coupling between the resonant cavities, it is difficult to distinguish the central frequency and muffler amount of each resonant cavity, so it is impossible to provide a reference for the resonant cavity design of a specific frequency band. Modifying the existing broadband muffler for single resonant cavity performance testing is relatively troublesome and requires the consumption of multiple products. In addition, the broadband mufflers of different models have different shapes and volumes, and the shapes of the resonance cavities are mostly irregular. The data measured after the modification may have peculiarities. Summary of the invention

[0004] The object of the present invention is to provide a standard muffler structure in order to solve the above problems.

[0005] Another object of the present invention is to provide a method for quickly establishing a noise reduction performance database based on the above-mentioned standard muffler structure.

[0006] The present invention is achieved through the following scheme:

[0007] A standard muffler structure is composed of an upper shell, a lower shell, an inner core frame and a perforated plate. The inner core frame, the upper shell, the lower shell and the perforated plate are engaged with each other to form a main pipeline and a muffler cavity.

[0008] The main pipeline is a round straight pipe with an inner surface radius of 20-40 mm.

[0009] The muffler cavity is a hollow cylinder or a part of a hollow cylinder.

[0010] The length of the main pipeline of the upper shell is not less than 100mm. An outer ring surface of the upper shell and an inner ring surface of the upper shell are arranged along the radial direction of the main pipeline. The outer ring surface of the upper shell serves as a positioning groove, and the inner ring surface of the upper shell serves as an upper cover plate.

[0011] An upper shell step surface is provided between the inner surface of the upper shell main pipeline and the inner annular surface of the upper shell, serving as an inner core frame mounting seat, and the width of the step surface is consistent with the wall thickness of the inner core frame.

[0012] The length of the lower shell main pipeline is not less than 100mm. The lower shell outer ring surface and the lower shell inner ring surface are provided along the radial direction of the main pipeline. The height of the lower shell outer ring surface is 15-100mm. The lower shell inner ring surface acts as a lower cover plate and has a width of not less than 10mm.

[0013] There is a lower shell step surface between the inner surface of the lower shell main pipeline and the inner annular surface of the lower shell, which serves as an inner core frame mounting seat, and the width of the lower shell step surface is consistent with the wall thickness of the inner core frame.

[0014] The inner core skeleton is a round tube with a rectangular hole on the side, with a wall thickness of 2-4mm. The width of the rectangular hole is at least 2mm greater than the height of the outer ring surface of the lower shell, and the upper and lower edges are provided with inner core skeleton step surfaces.

[0015] The outer dimensions of the perforated plate are consistent with the rectangular hole dimensions of the inner core frame, and are provided with round holes or square holes, and are installed on the inner core frame through the upper shell step surface, the lower shell step surface and the inner core frame step surface.

[0016] A method for quickly establishing a noise reduction performance database based on the above standard muffler structure, the specific steps are:

[0017] (a) Taking the main pipe radius, silencer cavity height, silencer cavity radial width, silencer cavity center angle, inner core skeleton wall thickness and perforated plate opening area as variables, and transmission loss amplitude and center frequency as dependent variables, a standard silencer muffler performance database is designed according to actual needs;

[0018] (b) selecting at least one set of variable parameters from a standard muffler noise reduction performance database to obtain a standard muffler object;

[0019] (c) Obtain the standard muffler transmission loss curve through the transmission loss test bench test, and record the corresponding center frequency and transmission loss amplitude;

[0020] (d) The center frequency and transmission loss amplitude of the remaining standard mufflers in the database are calculated according to the following empirical formula:

[0021]

[0022]

[0023] Wherein, f is the center frequency of the target muffler, A is the transmission loss amplitude of the target muffler, a is the ratio of the opening area of ​​the target muffler to the opening area of ​​the reference standard muffler, b is the ratio of the effective perforation length of the target muffler to the effective perforation length of the reference standard muffler, c is the ratio of the muffler cavity volume of the target muffler to the muffler cavity volume of the reference standard muffler, d is the ratio of the main pipe area of ​​the target muffler to the main pipe area of ​​the reference standard muffler, n is the number of test data sets of the reference standard muffler, σ is the opening rate, L is the effective perforation length, α is the central angle of the muffler cavity, H is the height of the muffler cavity, W is the radial width of the muffler cavity, R is the radius of the main pipe, t is the thickness of the perforated plate, S is the opening area of ​​the perforated plate,

[0024] In this scheme, a is the ratio of the opening area of ​​the target muffler to the opening area of ​​the reference standard muffler. The reason is that when the main pipe radius and the muffler cavity height are different, different opening areas may obtain the same opening ratio.

[0025] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0026] 1. The present invention provides convenience for measuring the sound-absorbing characteristics of standard silencers with different structural parameters. Through this structure, the transmission loss of standard silencers with different structural parameters can be measured. By changing the combination of the upper shell, the lower shell, the inner core skeleton and the perforated plate, standard silencers with different radial widths of the silencer cavity, heights of the silencer cavity and opening areas can be obtained. By repeatedly using the upper shell, the lower shell, the inner core skeleton and the perforated plate of the structure, the sound-absorbing characteristics of more silencers can be obtained with fewer physical measurements. The operation is simple, the sample utilization rate is high, and the development cost is saved.

[0027] 2. The method for quickly establishing a standard silencer noise reduction performance database of the present invention takes six parameters, namely, the radius of the main pipe, the height of the silencer cavity, the radial width of the silencer cavity, the central angle of the silencer cavity, the wall thickness of the inner core skeleton and the opening area of ​​the perforated plate, as variables, and the transmission loss amplitude and the center frequency as dependent variables. A standard silencer noise reduction database can be designed according to actual needs. The center frequency and transmission loss amplitude of some standard silencers in the database are obtained through transmission loss tests. The center frequency and transmission loss amplitude of the remaining standard silencers are calculated using empirical formulas to build a standard silencer noise reduction performance database. The standard silencer performance database established by the present invention can replace the traditional theoretical formula in the development of broadband silencers, guide the design of silencer schemes, and after obtaining the remaining undetermined structural parameters in the database according to the determined structural parameters and design goals such as the main pipe radius and the perforated plate thickness, only a few tuning corrections are needed to obtain a design scheme that meets the performance goals; in the later actual vehicle tuning, it can provide a reference for sample modification, and according to the modification goals, the muffler that meets the requirements can be searched in the database, which reduces the number of trial and error, shortens the development cycle, and saves development costs.

[0028] In addition, when it is impossible to obtain a physical standard muffler or to conduct a transmission loss experiment, establishing a database through simulation according to the above method should also be regarded as the content of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the standard muffler structure of the present invention;

[0030] Figure 2 It is a cross-sectional schematic diagram of the standard muffler structure of the present invention;

[0031] Figure 3 It is a schematic diagram of the standard muffler noise reduction performance database (part) of the present invention;

[0032] In the figure: 1. main pipe; 2. upper shell; 3. lower shell; 4. inner core skeleton; 5. perforated plate; 6. muffler cavity; 7. outer annular surface of upper shell; 8. inner annular surface of upper shell; 9. step surface of upper shell; 10. outer annular surface of lower shell; 11. inner annular surface of lower shell; 12. step surface of lower shell; 13. step surface of inner core skeleton; 14. circular hole of perforated plate. DETAILED DESCRIPTION

[0033] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0034] Any feature disclosed in this specification (including any additional claims and abstract), unless otherwise stated, may be replaced by other equivalent or alternative features having similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0035] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a predetermined direction, be constructed and operated in a predetermined direction, and therefore cannot be understood as a limitation on the present invention.

[0036] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features.

[0037] Example 1

[0038] like Figure 1-2 As shown, the present invention provides a technical solution:

[0039] A standard muffler structure, which consists of an upper shell 2, a lower shell 3, an inner core skeleton 4 and a perforated plate 5. The inner core skeleton 4, the upper shell 2, the lower shell 3 and the perforated plate 5 are engaged with each other to form a main pipe 1 and a muffler cavity 6. The main pipe 1 is a circular straight pipe with an inner surface radius of 20-40 mm, which is 30 mm in this embodiment, that is, the radius of the main pipe of the standard muffler is 30 mm. The muffler cavity 6 is a hollow cylinder or a partially hollow cylinder, which is a hollow cylinder in this embodiment. The main pipe length of the upper shell 2 is not less than 100 mm. The main pipeline of the upper shell 2 is 100mm long. The upper shell 2 is provided with an upper shell outer ring surface 7 and an upper shell inner ring surface 8 along the radial direction of the main pipeline. The upper shell outer ring surface 7 acts as a positioning slot, and the upper shell inner ring surface 8 acts as an upper cover plate. There is a step surface 9 between the inner surface of the main pipeline of the upper shell 2 and the upper shell inner ring surface 8, which serves as a mounting seat for the inner core skeleton 4. The main pipeline length of the lower shell 3 is not less than 100mm. In this embodiment, the main pipeline length of the lower shell 3 is 100mm. The lower shell 3 is provided with a lower shell outer ring surface 10 and a lower shell inner ring surface 11 along the radial direction of the main pipeline. The lower shell The height of the outer ring surface 10 is 15-100mm. The height of the outer ring surface 10 of the lower shell in this embodiment is 80mm, that is, the height of the muffler cavity is 80mm. The inner ring surface 11 of the lower shell acts as a lower cover plate and has a width of not less than 10mm. The width of the inner ring surface 11 of the lower shell in this embodiment is 60mm, that is, the radial width of the muffler cavity is 60mm. There is a step surface 12 between the inner surface of the main pipeline of the lower shell 3 and the inner ring surface 11 of the lower shell, which serves as a mounting seat for the inner core skeleton 4. The inner core skeleton 4 is a round tube with a rectangular hole on the side, and the wall thickness is 2-4mm. The wall thickness of the inner core skeleton in this embodiment is 3mm The width of the rectangular hole is at least 2mm greater than the height of the outer ring surface 10 of the lower shell. In this embodiment, the rectangular hole is 84mm wide and 87mm long, and the upper and lower edges are provided with inner core skeleton step surfaces 13, which serve as a mounting seat for the perforated plate 5. The external dimensions of the perforated plate 5 are consistent with the dimensions of the rectangular hole of the inner core skeleton 4, and are provided with round holes or square holes. The inner core skeleton is provided with 50 round holes with a radius of 2mm or 234 round holes with a radius of 2mm, or the perforated plate 5 is not provided, and is installed on the inner core skeleton 4 through the upper shell step surface 9, the lower shell step surface 12 and the inner core skeleton step surface 13.

[0040] Example 2

[0041] The present invention provides a technical solution:

[0042] A standard muffler structure, which consists of an upper shell 2, a lower shell 3, an inner core skeleton 4 and a perforated plate 5. The inner core skeleton 4 and the upper shell 2, the lower shell 3 and the perforated plate 5 are engaged with each other to form a main pipe 1 and a muffler cavity 6. The main pipe 1 is a circular straight pipe with an inner surface radius of 20-40mm, which is 30mm in this embodiment, that is, the radius of the main pipe of the standard muffler is 30mm. The muffler cavity 6 is a hollow cylinder or a partially hollow cylinder, which is a hollow cylinder in this embodiment. The main pipe length of the upper shell 2 is not less than 100mm. The main pipeline of the shell 2 is 100mm long. The upper shell 2 is provided with an upper shell outer ring surface 7 and an upper shell inner ring surface 8 along the radial direction of the main pipeline. The upper shell outer ring surface 7 serves as a positioning slot, and the upper shell inner ring surface 8 serves as an upper cover plate. There is a step surface 9 between the inner surface of the main pipeline of the upper shell 2 and the upper shell inner ring surface 8, which serves as a mounting seat for the inner core skeleton 4. The main pipeline length of the lower shell 3 is not less than 100mm. In this embodiment, the main pipeline length of the lower shell 3 is 100mm. The lower shell 3 is provided with a lower shell outer ring surface 10 and a lower shell inner ring surface 11 along the radial direction of the main pipeline. The height of the annular surface 10 is 15-100mm. In this embodiment, the height of the outer annular surface 10 of the lower shell is 80mm, that is, the height of the muffler cavity is 80mm. The inner annular surface 11 of the lower shell acts as a lower cover plate and has a width of not less than 10mm. In this embodiment, the width of the inner annular surface 11 of the lower shell is 60mm, that is, the radial width of the muffler cavity is 60mm. There is a step surface 12 between the inner surface of the main pipeline of the lower shell 3 and the inner annular surface 11 of the lower shell, which serves as a mounting seat for the inner core skeleton 4. The inner core skeleton 4 is a round tube with a rectangular hole on the side, and the wall thickness is 2-4mm. The wall thickness of the inner core skeleton in this embodiment is 2.5mm m, the width of the rectangular hole is at least 2mm greater than the height of the outer ring surface 10 of the lower shell. In this embodiment, the rectangular hole is 84mm wide and 87mm long, and the upper and lower edges are provided with inner core skeleton step surfaces 13, which serve as a mounting seat for the perforated plate 5. The external dimensions of the perforated plate 5 are consistent with the dimensions of the rectangular hole of the inner core skeleton 4, and are provided with round holes or square holes. The inner core skeleton is opened in the form of 50 round holes with a radius of 2mm or 234 round holes with a radius of 2mm, or the perforated plate 5 is not provided, and is installed on the inner core skeleton 4 through the upper shell step surface 9, the lower shell step surface 12 and the inner core skeleton step surface 13.

[0043] Example 3

[0044] The present invention provides a technical solution:

[0045] A standard muffler structure, which consists of an upper shell 2, a lower shell 3 and an inner core frame 4. The inner core frame 4, the upper shell 2 and the lower shell 3 are engaged with each other to form a main pipe 1 and a muffler cavity 6. The main pipe 1 is a circular straight pipe with an inner surface radius of 20-40 mm, which is 30 mm in this embodiment, that is, the radius of the main pipe of the standard muffler is 30 mm. The muffler cavity 6 is a hollow cylinder or a partially hollow cylinder, which is a hollow cylinder in this embodiment. The main pipe length of the upper shell 2 is not less than 100 mm. The upper shell 2 in this embodiment The main pipeline length is 100mm, the upper shell 2 is provided with an upper shell outer ring surface 7 and an upper shell inner ring surface 8 along the radial direction of the main pipeline, the upper shell outer ring surface 7 acts as a positioning slot, and the upper shell inner ring surface 8 acts as an upper cover plate. There is a step surface 9 between the inner surface of the main pipeline of the upper shell 2 and the upper shell inner ring surface 8, which serves as a mounting seat for the inner core skeleton 4. The main pipeline length of the lower shell 3 is not less than 100mm. In this embodiment, the main pipeline length of the lower shell 3 is 100mm. The lower shell 3 is provided with a lower shell outer ring surface 10 and a lower shell inner ring surface 11 along the radial direction of the main pipeline. The height of the outer ring surface 10 of the lower shell is 15-100mm. In this embodiment, the height of the outer ring surface 10 of the lower shell is 80mm, that is, the height of the muffler cavity is 80mm. The inner ring surface 11 of the lower shell acts as a lower cover plate and has a width of not less than 10mm. In this embodiment, the width of the inner ring surface 11 of the lower shell is 40mm, that is, the radial width of the muffler cavity is 40mm. There is a step surface 12 between the inner surface of the main pipeline of the lower shell 3 and the inner ring surface 11 of the lower shell, which serves as a mounting seat for the inner core skeleton 4. The inner core skeleton 4 is a round tube with a rectangular hole on the side and a wall thickness of 2-4mm. In this embodiment, The wall thickness of the inner core skeleton in this embodiment is 3mm, and the width of the rectangular hole is at least 2mm greater than the height of the outer ring surface 10 of the lower shell. The width of the rectangular hole in this embodiment is 84mm and the length is 87mm, and the upper and lower edges are provided with inner core skeleton step surfaces 13, which serve as a mounting seat for the perforated plate 5. The external dimensions of the perforated plate 5 are consistent with the dimensions of the rectangular hole of the inner core skeleton 4, and are provided with round holes or square holes. The inner core skeleton in this embodiment has 234 round holes with a radius of 2mm, which are installed on the inner core skeleton 4 through the upper shell step surface 9, the lower shell step surface 12 and the inner core skeleton step surface 13.

[0046] Example 4

[0047] The present invention provides a technical solution:

[0048] A standard muffler structure, which consists of an upper shell 2, a lower shell 3 and an inner core frame 4. The inner core frame 4, the upper shell 2 and the lower shell 3 are engaged with each other to form a main pipe 1 and a muffler cavity 6. The main pipe 1 is a circular straight pipe with an inner surface radius of 20-40 mm, which is 30 mm in this embodiment, that is, the radius of the main pipe of the standard muffler is 30 mm. The muffler cavity 6 is a hollow cylinder or a partially hollow cylinder, which is a hollow cylinder in this embodiment. The main pipe length of the upper shell 2 is not less than 100 mm. The upper shell 2 in this embodiment The main pipeline length is 100mm, the upper shell 2 is provided with an upper shell outer ring surface 7 and an upper shell inner ring surface 8 along the radial direction of the main pipeline, the upper shell outer ring surface 7 acts as a positioning slot, and the upper shell inner ring surface 8 acts as an upper cover plate. There is a step surface 9 between the inner surface of the main pipeline of the upper shell 2 and the upper shell inner ring surface 8, which serves as a mounting seat for the inner core skeleton 4. The main pipeline length of the lower shell 3 is not less than 100mm. In this embodiment, the main pipeline length of the lower shell 3 is 100mm. The lower shell 3 is provided with a lower shell outer ring surface 10 and a lower shell inner ring surface 11 along the radial direction of the main pipeline. The height of the outer ring surface 10 of the lower shell is 15-100mm. In this embodiment, the height of the outer ring surface 10 of the lower shell is 75mm, that is, the height of the muffler cavity is 75mm. The inner ring surface 11 of the lower shell acts as a lower cover plate and has a width of not less than 10mm. In this embodiment, the width of the inner ring surface 11 of the lower shell is 40mm, that is, the radial width of the muffler cavity is 40mm. There is a step surface 12 between the inner surface of the main pipeline of the lower shell 3 and the inner ring surface 11 of the lower shell, which serves as a mounting seat for the inner core skeleton 4. The inner core skeleton 4 is a round tube with a rectangular hole on the side and a wall thickness of 2-4mm. In this embodiment, The wall thickness of the inner core skeleton in this embodiment is 3mm, and the width of the rectangular hole is at least 2mm greater than the height of the outer ring surface 10 of the lower shell. The width of the rectangular hole in this embodiment is 84mm and the length is 87mm, and the upper and lower edges are provided with inner core skeleton step surfaces 13, which serve as a mounting seat for the perforated plate 5. The external dimensions of the perforated plate 5 are consistent with the dimensions of the rectangular hole of the inner core skeleton 4, and are provided with round holes or square holes. The inner core skeleton in this embodiment has 234 round holes with a radius of 2mm, which are installed on the inner core skeleton 4 through the upper shell step surface 9, the lower shell step surface 12 and the inner core skeleton step surface 13.

[0049] Example 5

[0050] The present invention provides a technical solution:

[0051] A standard muffler structure, which consists of an upper shell 2, a lower shell 3 and an inner core skeleton 4. The inner core skeleton 4, the upper shell 2 and the lower shell 3 are engaged with each other to form a main pipe 1 and a muffler cavity 6. The main pipe 1 is a circular straight pipe with an inner surface radius of 20-40mm, which is 35m in this embodiment, that is, the radius of the main pipe of the standard muffler is 30mm. The muffler cavity 6 is a hollow cylinder or a partially hollow cylinder, which is a hollow cylinder in this embodiment. The main pipe length of the upper shell 2 is not less than 100mm. The upper shell 2 in this embodiment is The length of the main pipeline is 100mm. The upper shell 2 is provided with an upper shell outer ring surface 7 and an upper shell inner ring surface 8 along the radial direction of the main pipeline. The upper shell outer ring surface 7 acts as a positioning slot, and the upper shell inner ring surface 8 acts as an upper cover plate. There is a step surface 9 between the inner surface of the main pipeline of the upper shell 2 and the upper shell inner ring surface 8, which serves as a mounting seat for the inner core skeleton 4. The length of the main pipeline of the lower shell 3 is not less than 100mm. In this embodiment, the length of the main pipeline of the lower shell 3 is 100mm. The lower shell 3 is provided with a lower shell outer ring surface 10 and a lower shell inner ring surface 11 along the radial direction of the main pipeline. The height of the outer ring surface 10 of the lower shell is 15-100mm. In this embodiment, the height of the outer ring surface 10 of the lower shell is 75mm, that is, the height of the muffler cavity is 75mm. The inner ring surface 11 of the lower shell acts as a lower cover plate and has a width of not less than 10mm. In this embodiment, the width of the inner ring surface 11 of the lower shell is 40mm, that is, the radial width of the muffler cavity is 40mm. There is a step surface 12 between the inner surface of the main pipeline of the lower shell 3 and the inner ring surface 11 of the lower shell, which serves as a mounting seat for the inner core skeleton 4. The inner core skeleton 4 is a round tube with a rectangular hole on the side and a wall thickness of 2-4mm. In this embodiment, The wall thickness of the inner core skeleton in this embodiment is 3mm, and the width of the rectangular hole is at least 2mm greater than the height of the outer ring surface 10 of the lower shell. The width of the rectangular hole in this embodiment is 84mm and the length is 87mm, and the upper and lower edges are provided with inner core skeleton step surfaces 13, which serve as a mounting seat for the perforated plate 5. The external dimensions of the perforated plate 5 are consistent with the dimensions of the rectangular hole of the inner core skeleton 4, and are provided with round holes or square holes. The inner core skeleton in this embodiment has 234 round holes with a radius of 2mm, which are installed on the inner core skeleton 4 through the upper shell step surface 9, the lower shell step surface 12 and the inner core skeleton step surface 13.

[0052] The structural comparison of Examples 1 to 5 is as follows Figure 3 As shown:

[0053] The different standard muffler structures in Example 1 are shown as numbers 1 to 3; the different standard muffler structures in Example 2 are shown as numbers 4 to 6; the different standard muffler structures in Example 3 are shown as numbers 7 to 9; the different standard muffler structures in Example 4 are shown as numbers 10 to 12; the different standard muffler structures in Example 5 are shown as numbers 13 to 15;

[0054] This scheme can produce multiple groups of samples, and samples with the same main pipe can be selected to form different mufflers. For samples with the same main pipe size, select an upper shell, match it with a lower shell with a matching inner ring surface size, and then match it with an inner core frame that matches the length of the lower shell to form a standard muffler. At this time, the opening area of ​​the muffler is the largest; then select multiple perforated plates that match the size of the inner core frame but have different opening areas and install them on the inner core frame respectively, which can form a standard muffler with the same silencer cavity width and silencer cavity height but different perforated plate opening areas. Repeat the above operation, and obtain different standard mufflers by selecting upper shells with different inner ring surface widths, matching them with lower shells with different outer ring surface heights, inner core frames that match the lower shells, and perforated plates with different opening areas that match the inner core frames.

[0055] Existing embodiment 1 (second set of variable parameters) muffler, remove the perforated plate to obtain Figure 3 The muffler corresponding to the third set of variable parameters. If you want to obtain the muffler corresponding to the eighth and ninth sets of variable parameters in the future, you only need to make the corresponding upper and lower shells and combine them with the existing inner core skeleton and perforated plate. If you want to obtain the muffler corresponding to the first set of parameters, you only need to make a new corresponding perforated plate and replace the existing perforated plate.

[0056] Example 6

[0057] A method for quickly establishing a noise reduction performance database based on the above standard muffler structure, the specific steps are:

[0058] (a) With the main pipe radius, silencer cavity height, silencer cavity radial width, silencer cavity center angle, inner core skeleton wall thickness and perforated plate opening area as variables, and the transmission loss amplitude and center frequency as dependent variables, a standard silencer muffler performance database is designed according to actual needs. This embodiment (part) is as follows Figure 3 As shown;

[0059] The reason for using six parameters to establish data is that the silencing performance of the Helmholtz muffler, the center frequency depends on the volume of the muffler cavity, the mass distribution (shape) of the muffler cavity, the length of the throat, and the cross-sectional area of ​​the throat; the transmission loss amplitude depends on the size of the main pipe, the volume of the muffler cavity, the mass distribution (shape) of the muffler cavity, the length of the throat, and the cross-sectional area of ​​the throat. Among the six selected parameters, the radius of the main pipe corresponds to the size of the main pipe, the height of the muffler cavity, the radial width of the muffler cavity, and the rounded angle of the muffler cavity correspond to the volume and mass distribution (shape) of the muffler cavity, the wall thickness of the inner core skeleton 4 corresponds to the length of the throat, and the opening area of ​​the perforated plate 5 corresponds to the cross-sectional area of ​​the throat. Through the above six parameters, a standard muffler can be determined.

[0060] (b) Select at least one set of variable parameters from the standard muffler performance database to obtain a standard muffler object; specifically, select a set of variable parameters from the database to determine a standard muffler structure. According to the selected parameters, obtain three-dimensional structure data through designer drawing or automated program, and then make a sample.

[0061] (c) Obtain the standard muffler transmission loss curve through the transmission loss test bench test, and record the corresponding center frequency and transmission loss amplitude;

[0062] (d) The center frequency and transmission loss amplitude of the remaining standard mufflers in the database are calculated according to the following empirical formula:

[0063]

[0064]

[0065] Wherein, f is the center frequency of the target muffler, A is the transmission loss amplitude of the target muffler, a is the ratio of the opening area of ​​the target muffler to the opening area of ​​the reference standard muffler, b is the ratio of the effective perforation length of the target muffler to the effective perforation length of the reference standard muffler, c is the ratio of the muffler cavity volume of the target muffler to the muffler cavity volume of the reference standard muffler, d is the ratio of the main pipe area of ​​the target muffler to the main pipe area of ​​the reference standard muffler, n is the number of test data sets of the reference standard muffler, σ is the opening rate, L is the effective perforation length, α is the central angle of the muffler cavity, H is the height of the muffler cavity, W is the radial width of the muffler cavity, R is the radius of the main pipe, t is the thickness of the perforated plate, and S is the opening area of ​​the perforated plate.

[0066] The amount of center frequency and transmission loss amplitude data obtained from the experiment in this scheme is specifically as follows: for a single muffler, the center frequency and transmission loss amplitude obtained from the experiment are each a specific value, and the center frequency and transmission loss amplitude of a single muffler obtained by subsequent calculations are also each a specific value. The accuracy of the center frequency and transmission loss amplitude obtained by calculation depends on the number of experimental data referenced during the calculation. Therefore, increasing the proportion of experimental data in the database can effectively improve the accuracy of the database. Obviously, the database can be completely obtained by experiment, and the database accuracy is the highest at this time.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A standard muffler structure, characterized in that: The structure is composed of an upper shell (2), a lower shell (3), an inner core frame (4) and a perforated plate (5); the inner core frame (4) and the upper shell (2), the lower shell (3) and the perforated plate (5) are engaged with each other to form a main pipeline (1) and a muffler cavity (6).

2. A standard muffler structure according to claim 1, characterized in that: The main pipeline (1) is a circular straight pipe with an inner surface radius of 20-40 mm.

3. A standard muffler structure according to claim 1, characterized in that: The muffler cavity (6) is a hollow cylinder or a part of a hollow cylinder.

4. A standard muffler structure according to claim 1, characterized in that: The main pipeline of the upper shell (2) is not less than 100 mm long, and an upper shell outer ring surface (7) and an upper shell inner ring surface (8) are provided along the radial direction of the main pipeline. The upper shell outer ring surface (7) serves as a positioning slot, and the upper shell inner ring surface (8) serves as an upper cover plate.

5. A standard muffler structure according to claim 4, characterized in that: An upper shell step surface (9) is provided between the inner surface of the main pipeline of the upper shell (2) and the inner ring surface (8) of the upper shell, serving as a mounting seat for the inner core skeleton (4), and the width of the upper shell step surface (9) is consistent with the wall thickness of the inner core skeleton (4).

6. A standard muffler structure according to claim 1, characterized in that: The main pipeline of the lower shell (3) is not less than 100 mm long, and a lower shell outer ring surface (10) and a lower shell inner ring surface (11) are provided along the radial direction of the main pipeline. The height of the lower shell outer ring surface (10) is 15-100 mm, and the lower shell inner ring surface (11) acts as a lower cover plate and has a width of not less than 10 mm.

7. A standard muffler structure according to claim 6, characterized in that: A lower shell step surface (12) is provided between the inner surface of the main pipeline of the lower shell (3) and the inner ring surface (11) of the lower shell, serving as a mounting seat for the inner core skeleton (4), and the width of the lower shell step surface (12) is consistent with the wall thickness of the inner core skeleton (4).

8. A standard muffler structure according to claim 7, characterized in that: The inner core skeleton (4) is a round tube with a rectangular hole on the side, with a wall thickness of 2-4 mm. The width of the rectangular hole is at least 2 mm greater than the height of the outer ring surface (10) of the lower shell, and the upper and lower edges are provided with inner core skeleton step surfaces (13).

9. A standard muffler structure according to claim 1, characterized in that: The perforated plate (5) has an external dimension consistent with the rectangular hole dimension of the inner core frame (4), has a circular hole or a square hole, and is mounted on the inner core frame (4) via the upper shell step surface (9), the lower shell step surface (12) and the inner core frame step surface (13).

10. A method for quickly establishing a noise reduction performance database based on the standard muffler structure according to any one of claims 1 to 9, characterized in that: The specific steps are: (a) Taking the main pipe radius, silencer cavity height, silencer cavity radial width, silencer cavity center angle, inner core skeleton wall thickness and perforated plate opening area as variables, and transmission loss amplitude and center frequency as dependent variables, a standard silencer muffler performance database is designed according to actual needs; (b) selecting at least one set of variable parameters from a standard muffler noise reduction performance database to obtain a standard muffler object; (c) Obtain the standard muffler transmission loss curve through the transmission loss test bench test, and record the corresponding center frequency and transmission loss amplitude; (d) The center frequency and transmission loss amplitude of the remaining standard mufflers in the database are calculated according to the following empirical formula: Wherein, f is the center frequency of the target muffler, A is the transmission loss amplitude of the target muffler, a is the ratio of the opening area of ​​the target muffler to the opening area of ​​the reference standard muffler, b is the ratio of the effective perforation length of the target muffler to the effective perforation length of the reference standard muffler, c is the ratio of the muffler cavity volume of the target muffler to the muffler cavity volume of the reference standard muffler, d is the ratio of the main pipe area of ​​the target muffler to the main pipe area of ​​the reference standard muffler, n is the number of test data sets of the reference standard muffler, σ is the opening rate, L is the effective perforation length, α is the central angle of the muffler cavity, H is the height of the muffler cavity, W is the radial width of the muffler cavity, R is the radius of the main pipe, t is the thickness of the perforated plate, and S is the opening area of ​​the perforated plate.

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