Multi-cavity Helmholtz silencer tuning tool and tuning method

Abstract

The invention discloses a multi-cavity Helmholtz silencer tuning tool and tuning method, the tuning tool comprises a plurality of silencing cavities arranged in parallel, the silencing cavities are connected with a central pipe through throat pipes, two ends of the central pipe are provided with jigs connected with equipment, and the housing of each silencing cavity is provided with scale marks; wherein the top of each silencing cavity is in threaded connection with an upper cover, an end cover located at the bottom of the upper cover is further arranged in the silencing cavity, the upper cover is connected with a barrel extending in the circumferential direction of the upper cover, guide rods penetrating through the upper cover are arranged at the two ends of the end cover, and sliding rails matched with sliding grooves of the guide rods are arranged on the inner wall of the upper cover; a lead screw arranged on the end cover is further arranged between the guide rods, the lead screw penetrates through the upper cover and is connected with an actuator so as to push the end cover to move axially, the CAE analysis stage can be skipped, a desired result can be directly obtained through physical testing, and multi-state testing can be rapidly carried out.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile intake resonance systems, and in particular relates to a multi-cavity Helmholtz muffler tuning tool and a tuning method. Background Art

[0002] With the development of science and technology and economy, people's demand for automobile consumer products is no longer just to meet basic functions, and the pursuit of quietness and comfort of automobiles is also increasing;

[0003] For example, NVH performance is a comprehensive issue to measure the quality of automobile manufacturing, mainly involving noise, vibration and acoustic roughness. As a field that major OEMs are competing to invest in research and development, NVH performance has also attracted further attention from the market and users. Plug-in hybrid models have been very popular in the market in recent years due to their excellent energy-saving and emission reduction technologies. Intake noise control has also become a key research object in the field of intake resonance system technology. Due to the wide range of engine intervention and large operating speed range of plug-in hybrid systems, higher requirements for intake noise indicators at multiple speeds are often required. Multiple Helmholtz mufflers are often arranged in a limited cabin environment for silencing;

[0004] In the traditional intake tuning process, multi-cavity Helmholtz silencers often require multiple rounds of data design, CAE analysis, rapid prototyping, and loss testing.

[0005] At present, for example, Chinese invention patent CN202010772477.7 discloses a method and device for designing an automobile muffler, which determines the target main pipe diameter, target cavity height, target opening method, target opening area and target volume of the target muffler; determines the target basic muffler element corresponding to the target muffler and the opening area and volume of the target basic muffler element in the database according to the target main pipe diameter, target cavity height and target opening method; determines the target transmission loss of the target muffler according to the target opening area and target volume of the target muffler, the opening area and volume of the target basic muffler element and a preset correction empirical formula, and can establish a basic muffler element database in advance, and select the simulation data in the corresponding database according to the muffler actually used at the tuning site, and correct the data according to the parameter difference to determine the transmission loss, but it involves many parameters and the design steps are still relatively complicated;

[0006] That is, the above-mentioned existing technologies all have problems such as long test development cycle and high process R&D investment cost, which are difficult to meet the current situation of tight project cycle and shortage of human resources. Summary of the invention

[0007] The purpose of the present invention is to overcome the defects of the prior art and provide a multi-cavity Helmholtz muffler tuning tool and tuning method, which can skip the CAE analysis stage, directly obtain the desired results by physical testing, quickly perform multi-state testing, further optimize the CAE analysis method, and improve the analysis accuracy.

[0008] The object of the present invention is achieved through the following technical solutions:

[0009] A multi-cavity Helmholtz muffler tuning tool, comprising a plurality of muffler cavities arranged in parallel, wherein the plurality of muffler cavities are connected to a central tube through throats, both ends of the central tube are provided with jigs connected to the equipment, and the outer shell of the muffler cavity has scale lines;

[0010] Among them, the top of each silencer cavity is threadedly connected to an upper cover, and the silencer cavity is also provided with an end cover located at the bottom of the upper cover, the upper cover is connected to a cylinder extending along its circumference, and guide rods passing through the upper cover are provided at both ends of the end cover, and the inner wall of the upper cover is provided with a slide rail that cooperates with the slide groove of the guide rod, and a screw rod is also provided on the end cover between the guide rods, and the screw rod passes through the upper cover and is connected to the actuator to push the end cover to move axially.

[0011] In one embodiment, the end cover is also equipped with a sealing ring that is interference fit with the inner wall of the silencer cavity. Through this embodiment, the end cover is provided with a sealing ring that is interference fit with the inner wall of the silencer cavity to ensure the sealing inside the silencer cavity.

[0012] In one embodiment, a connecting ring is provided on the top of the silencer cavity, the connecting ring has an internal thread, and the outer wall of the upper cover has an external thread that cooperates with the internal thread of the connecting ring. Through this embodiment, the connecting ring provided on the top of the silencer cavity is used to facilitate quick disassembly and assembly between the upper cover and the silencer cavity.

[0013] In one embodiment, the end cover is provided with a plurality of recessed holes, in which nut inserts are embedded, the screw rod and the guide rod are connected to the nut inserts, and the upper cover is provided with through holes corresponding to the positions of the recessed holes. Through this embodiment, the recessed holes provided on the end cover and the embedded nut inserts facilitate quick installation of the screw rod and the guide rod on the end cover, and the through holes corresponding to the recessed holes are provided for the screw rod and the guide rod to pass through the upper cover. Under the action of the actuator, the screw rod performs a linear motion, driving the end cover to move axially along the silencer cavity, and the provided guide rod maintains the stability of the end cover during axial movement.

[0014] In one embodiment, the actuator is disposed on the upper cover, and the output shaft of the actuator is threadedly connected to the lead screw.

[0015] In one embodiment, a notch is formed on the cylinder to allow the control line of the actuator to pass through the cylinder.

[0016] In one embodiment, the volume of each of the sound-absorbing containers is 3L.

[0017] The present invention also provides a multi-cavity Helmholtz muffler tuning method, based on the above-mentioned tuning tool, comprising the following steps:

[0018] Step S1, obtaining a tuning target;

[0019] Step S2: according to the tuning target, calculate and obtain multiple theoretical combinations that meet the tuning target requirements;

[0020] Step S3, selecting one of the multiple theoretical combinations in step S2, connecting the throat pipes of corresponding length and diameter to the muffler cavity and the center pipe respectively, and driving the end cover to move axially through the actuator to adjust the volume of the muffler cavity to the theoretical volume;

[0021] Step S4, respectively adjusting the volumes of the plurality of silencing cavities so that each silencing cavity corresponds to a tuning target frequency;

[0022] Step S5, performing a resonant cavity center frequency test;

[0023] Step S6, according to the test results, the actuator is driven by the controller to adjust the position of the end cover and the volume of the silencer cavity so that the measured results reach the target, and the actual silencer volume is obtained according to the scale on the outer shell of the silencer cavity.

[0024] In one embodiment, in step S2, the theoretical combination that meets the tuning target requirement is calculated as follows:

[0025]

[0026] Where f is the resonant frequency of the muffler, TL is the transmission loss, c is the speed of sound propagation in the medium, V is the volume of the muffler, r c is the radius of the throat, l c is the length of the throat, A p The cross-sectional area of ​​the main pipeline.

[0027] The beneficial effects of the present invention are:

[0028] In the early stage of development, according to the needs, this tuning tool and tuning method can be used to directly perform simulation tests, skip the analysis link, improve efficiency, and meet the muffler simulation tests of different needs. It can skip the CAE analysis stage and use physical tests to directly obtain the desired results, quickly perform multi-state tests, further optimize the CAE analysis method, and improve the analysis accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings, wherein:

[0030] Figure 1 Shows a schematic diagram of the structure of the present invention (explosion diagram);

[0031] Figure 2 Shows a schematic diagram of the structure of the present invention (top view);

[0032] Figure 3 Shows a schematic diagram of the structure of the present invention (front view);

[0033] Figure 4 Shows Figure 2 Sectional view at AA in the middle;

[0034] Figure 5 Shows Figure 2 A magnified schematic diagram of the local structure at B in the middle;

[0035] Figure 6 A flow chart showing the tuning method of the present invention is shown;

[0036] In the drawings, like reference numerals are used for like parts. The drawings are not necessarily to scale.

[0037] Reference numerals:

[0038] 1-muffler cavity, 2-upper cover, 3-actuator, 4-screw, 5-center tube, 6-fixture, 7-throat, 8-sealing ring, 9-end cover, 10-nut insert, 11-plastic bearing, 12-guide rod, 13-screw, 14-scale line, 15-slide rail. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with the accompanying drawings.

[0040] In the current intake tuning process, multi-cavity Helmholtz silencers often require multiple rounds of data design, CAE analysis, rapid prototype production, and loss transmission testing. This results in long test development cycles and high R&D investment costs, making it difficult to meet the current tight project cycle and shortage of human resources.

[0041] The present invention provides a multi-cavity Helmholtz muffler tuning tool, such as Figure 1 As shown, it includes a plurality of muffler cavities 1 arranged in parallel, and the plurality of muffler cavities 1 are connected to a central tube 5 through a throat 7, and both ends of the central tube 5 are provided with a fixture connected to the equipment, and a scale mark 14 is provided on the outer shell of the muffler cavity 1;

[0042] Among them, the top of each muffler cavity 1 is threadedly connected to an upper cover 2, and an end cover 9 located at the bottom of the upper cover 2 is also arranged in the muffler cavity 1. The upper cover 2 is connected to a cylinder extending along its circumferential direction. Both ends of the end cover 9 are provided with guide rods 12 penetrating the upper cover 2, and the inner wall of the upper cover 2 is provided with a slide rail 15 matched with the slide groove of the guide rod 12. There is also a screw rod 13 arranged on the end cover 9 between the guide rods 12, and the screw rod 13 penetrates the upper cover 2 and is connected to the actuator 3 to push the end cover 9 to move axially;

[0043] It should be noted that the silencing of the intake system of the whole vehicle usually needs to be performed for multiple frequencies. The multi-cavity Helmholtz muffler is arranged at the engine port of the car. Multiple silencing cavities 1 arranged in parallel are respectively used for silencing at different frequencies to control the intake noise and improve the comfort of the user. Although according to the theoretical formula, after determining the diameter and length of the throat 7, the theoretical volume of the silencing cavity 1 can be obtained, but in actual application, there are other interference factors, and the silencing effect of directly applying the theoretical volume of the silencing cavity 1 cannot meet the requirements;

[0044] In this embodiment, if Figures 1 to 5 As shown, each muffler cavity 1 is connected to the central tube 5 through a throat 7, the top of the muffler cavity 1 is threadedly connected to the upper cover 2, the upper cover 2 is used to install the actuator 3 and set the cylinder, the cylinder has a slide rail 15 matched with the guide rod 12, and the end cover 9 is provided in the muffler cavity 1. The space between the end cover 9 and the throat 7 is the actual volume of the muffler cavity 1. The output shaft of the actuator 3 rotates to drive the screw 13 to rotate, and then the end cover 9 in the muffler cavity 1 is pushed to move along the axis of the muffler cavity 1, so that the actual volume of the muffler cavity 1 can be adjusted, that is, according to the model of the car and the historical data of the engine, etc., the actual volume of the muffler cavity 1 can be adjusted. After determining the silencing target and the diameter and length of the throat 7, the preliminary resonant cavity size is obtained according to the theoretical formula, the volume of the silencing cavity 1 is first adjusted according to the preliminary size, and then the resonant cavity center frequency test is performed. According to the test results, the volume of the silencing cavity 1 is fine-tuned until the target silencing effect is achieved. At this time, the current actual volume of the silencing cavity 1 can be recorded according to the scale line 14 on the outer shell of the silencing cavity 1. The simulation test is directly performed, skipping the analysis link, greatly improving efficiency, reducing personnel requirements, and by changing the throat 7 model, the muffler simulation test with different requirements can be quickly met;

[0045] Specifically, Figure 1 , Figure 2 as well as Figure 4 As shown, the end cover 9 is also equipped with a sealing ring 8 which is interference fit with the inner wall of the muffler cavity 1 to ensure the sealing of the muffler cavity 1 and the accuracy of the test;

[0046] In one embodiment, a replaceable throat pipe 7 is connected to the bottom of the muffler cavity 1. The throat pipe 7 and the center pipe 5 are both made by 3D printing, so that different types of throat pipes 7 can be replaced for testing, which can meet the testing of different car models.

[0047] In one embodiment, Figure 1 As shown, a connecting ring is provided on the top of the muffler cavity 1, the connecting ring has an internal thread, and the outer wall of the upper cover 2 has an external thread that matches the internal thread of the connecting ring, that is, the connecting ring provided on the top of the muffler cavity 1 facilitates quick disassembly and assembly between the upper cover 2 and the muffler cavity 1;

[0048] In one embodiment, Figure 1 As shown, the end cover 9 is provided with a plurality of recessed holes, in which a nut insert 10 is embedded, a screw rod 13 and a guide rod 12 are connected to the nut insert 10 through a threaded structure, and pass through a plastic bearing 11 above the end cover 9, and the upper cover 2 is provided with through holes corresponding to the positions of the recessed holes;

[0049] It should be noted that the concave hole opened on the end cover 9 and the embedded nut insert 10 facilitate the quick installation of the screw rod 13 and the guide rod 12 on the end cover 9, and the through hole corresponding to the concave hole is used for the screw rod 13 and the guide rod 12 to pass through the upper cover 2. Under the action of the actuator 3, the screw rod 13 performs linear motion, driving the end cover 9 to move axially along the muffler cavity 1, and the provided guide rod 12 keeps the end cover 9 stable during axial motion;

[0050] In one embodiment, Figure 1 As shown, each actuator 3 is fixed to the upper cover 2 by four screws 4, and the output shaft of the actuator 3 is threadedly connected with the screw rod 13, that is, the rotation of the output shaft of the actuator 3 drives the screw rod 13 to rotate, thereby pushing the end cover 9 to move axially to adjust the volume change of each muffler cavity 1;

[0051] In one embodiment, a notch is provided on the cylinder body to allow the control line of the actuator 3 to pass through the cylinder body, and the actuator 3 is connected to the controller;

[0052] In one embodiment, Figure 1 and Figure 3 As shown, in this embodiment, three muffler cavities 1 are arranged in parallel, and the volume of the three muffler cavities 1 is 3L, and corresponding scale lines 14 are engraved on the muffler cavity 1 of the outer shell, wherein each scale line is 15ml;

[0053] The present invention also provides a multi-cavity Helmholtz muffler tuning method, such as Figure 6 As shown, the following steps are included:

[0054] Step S1, obtaining a tuning target;

[0055] Step S2: according to the tuning target, calculate and obtain multiple theoretical combinations that meet the tuning target requirements;

[0056] Step S3, selecting one of the multiple theoretical combinations in step S2, connecting the throat pipes of corresponding length and diameter to the muffler cavity and the center pipe respectively, and driving the end cover to move axially through the actuator to adjust the volume of the muffler cavity to the theoretical volume;

[0057] Step S4, respectively adjusting the volumes of the plurality of silencing cavities so that each silencing cavity corresponds to a tuning target frequency;

[0058] Step S5, performing a resonant cavity center frequency test;

[0059] Step S6, according to the test results, the controller drives the actuator to adjust the position of the end cover and the volume of the muffler cavity so that the measured results reach the target, and the actual muffler volume is obtained according to the scale on the muffler cavity shell;

[0060] It should be noted that in the current intake tuning process, multi-cavity Helmholtz silencers often require multiple rounds of data design, CAE analysis, rapid prototype production, and loss transmission testing. There are problems such as long test development cycle and high process R&D investment costs, which are difficult to meet the current tight project cycle and shortage of human resources.

[0061] The tuning method provided by the present invention first determines the tuning target, that is, it can calculate a variety of theoretical combinations that meet the tuning target requirements based on information such as historical data of the automobile engine. The theoretical combination includes the diameter and length of the throat and the volume of the silencer cavity. Different throat diameters and lengths correspond to different volumes of the silencer cavity. The diameter and length of the throat can be selected and determined to determine the volume of the corresponding silencer cavity. The diameter and length of the throat can be selected according to the model of the car. The throat and the center tube are obtained by 3D printing, and then connected to the transmission loss test equipment through a fixture. The center frequency of the resonant cavity can be tested by adjusting the volume of the silencer cavity.

[0062] Specifically, as in the present embodiment, multiple silencing targets of different frequencies are first determined, and multiple theoretical combinations corresponding to each silencing target are obtained according to the theoretical formula, and then the diameter and length of a throat are determined according to the model of the car, and the volumes of multiple silencing cavities are first adjusted according to the preliminary size, and each silencing cavity corresponds to a silencing target, and then the center frequency test of the resonant cavity is performed, and according to the test results, the volume of each silencing cavity is fine-tuned until the target silencing effect is achieved, and at this time, the current actual silencing cavity volume can be recorded according to the scale line on the outer shell of the silencing cavity;

[0063] This method skips the CAE analysis stage, uses physical testing to directly obtain the desired results, quickly conducts multi-state testing, further optimizes the CAE analysis method, improves analysis accuracy, greatly improves efficiency, reduces personnel requirements, and can quickly meet different needs of muffler simulation testing by changing the throat model;

[0064] Specifically, in step S2, the theoretical combination calculation method that meets the tuning target requirement is as follows:

[0065]

[0066] Where f is the resonant frequency of the muffler, TL is the transmission loss, c is the speed of sound propagation in the medium, V is the volume of the muffler, r c is the radius of the throat, l c is the length of the throat, A p The cross-sectional area of ​​the main pipeline.

[0067] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "bottom", "top", "front", "back", "inside", "outside", "left", "right", etc. indicate orientations or positional relationships based on the orientations 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 specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0068] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims

1. A multi-cavity Helmholtz muffler tuning tool, characterized in that: It comprises a plurality of muffler cavities arranged in parallel, wherein the plurality of muffler cavities are connected to a central tube through throats, both ends of the central tube are provided with jigs connected to the equipment, and the outer shell of the muffler cavity has scale lines; Among them, the top of each silencer cavity is threadedly connected to an upper cover, and the silencer cavity is also provided with an end cover located at the bottom of the upper cover, the upper cover is connected to a cylinder extending along its circumference, and guide rods passing through the upper cover are provided at both ends of the end cover, and the inner wall of the upper cover is provided with a slide rail that cooperates with the slide groove of the guide rod, and a screw rod is also provided on the end cover between the guide rods, and the screw rod passes through the upper cover and is connected to the actuator to push the end cover to move axially.

2. A multi-cavity Helmholtz muffler tuning tool according to claim 1, characterized in that: The end cover is also equipped with a sealing ring which is interference fit with the inner wall of the muffler cavity.

3. A multi-cavity Helmholtz muffler tuning tool according to claim 2, characterized in that: A connecting ring is provided on the top of the muffler cavity, the connecting ring has an internal thread, and the outer wall of the upper cover has an external thread that matches the internal thread of the connecting ring.

4. A multi-cavity Helmholtz muffler tuning tool according to claim 1, characterized in that: The end cover is provided with a plurality of recessed holes, in which nut inserts are embedded, the screw rod and the guide rod are both connected to the nut inserts, and the upper cover is provided with through holes corresponding to the positions of the recessed holes.

5. A multi-cavity Helmholtz muffler tuning tool according to claim 1, characterized in that: The actuator is arranged on the upper cover, and the output shaft of the actuator is threadedly connected with the lead screw.

6. A multi-cavity Helmholtz muffler tuning tool according to claim 5, characterized in that: The cylinder is provided with a notch for allowing the control line of the actuator to pass through the cylinder.

7. A multi-cavity Helmholtz muffler tuning tool according to claim 1, characterized in that: The volume of each of the muffler containers is 3L.

8. A method for tuning a multi-cavity Helmholtz muffler, based on the tuning tool according to any one of claims 1 to 6, characterized in that: The steps include: Step S1, obtaining a tuning target; Step S2: according to the tuning target, calculate and obtain multiple theoretical combinations that meet the tuning target requirements; Step S3, selecting one of the multiple theoretical combinations in step S2, connecting the throat pipes of corresponding length and diameter to the muffler cavity and the center pipe respectively, and driving the end cover to move axially through the actuator to adjust the volume of the muffler cavity to the theoretical volume; Step S4, respectively adjusting the volumes of the plurality of silencing cavities so that each silencing cavity corresponds to a tuning target frequency; Step S5, performing a resonant cavity center frequency test; Step S6, according to the test results, the actuator is driven by the controller to adjust the position of the end cover and the volume of the silencer cavity so that the measured results reach the target, and the actual silencer volume is obtained according to the scale on the outer shell of the silencer cavity.

9. A multi-cavity Helmholtz muffler tuning method according to claim 8, characterized in that: In step S2, the theoretical combination that meets the tuning target requirement is calculated as follows: Where f is the resonant frequency of the muffler, TL is the transmission loss, c is the speed of sound propagation in the medium, V is the volume of the muffler, r c is the radius of the throat, l c is the length of the throat, A p The cross-sectional area of ​​the main pipeline.

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