Broadband silencer for fuel cell vehicles

Abstract

The wideband silencer for a fuel cell vehicle includes a first shell (100), a second shell (200), and an inner tube (300). The first shell (100) and the second shell (200) are connected to form a sealed cavity. The inner tube (300) is installed in the sealed cavity. The inner tube (300) is formed with holes or grooves, and a plurality of sound-absorbing structures are formed in the sealed cavity. The second shell (200) is formed with a water collection section (201) along its side. One end of the exhaust port of the inner tube (300) is connected to a Venturi tube (400), and a drain pipe (401) communicating with the water collection section (201) is provided in the center of the Venturi tube (400). The silencer integrates the drainage structure with the Venturi tube, realizing a self-draining function during driving, and has excellent sound-absorbing function.

Description

Technical Field

[0001] The present invention relates to a muffler for automobiles, and particularly to a broadband muffler for fuel cell vehicles.

Background Art

[0002] Currently, due to the trend of new energy vehicles for passenger cars and the promotion of the country's new energy vehicle policy, major automobile manufacturers are advancing their development in the field of new energy vehicles. Among them, fuel cell vehicles, as one type of new energy vehicle, are currently developing rapidly. A fuel cell inhales fresh air, mixes and reacts with hydrogen, a combustible gas, and discharges electricity to the vehicle. However, in the process of the fuel cell system supplying power to the vehicle, broadband noise within a certain bandwidth may be generated from both the intake end and the exhaust end of the fuel cell system.

[0003] Currently, the countermeasures for broadband noise taken by automobile manufacturers and intake and exhaust system manufacturers are as follows: after measuring the noise data, determine the problem frequency through a large number of subjective and objective analyses, design a broadband muffler with a corresponding frequency band, and install it on the intake and exhaust pipes. This method for reducing broadband noise has the disadvantages of slow response, long period, and high cost.

[0004] Also, since liquid water is generated at the exhaust end of the fuel cell, a broadband muffler designed for broadband noise generated from a turbocharger cannot be applied to the exhaust end of a fuel cell vehicle, and water often accumulates in the muffler, causing failures.

Summary of the Invention

[0005] The object of the present invention is to solve the problem of noise reduction in fuel cell vehicles and provide a broadband muffler for fuel cell vehicles that integrates a water separation structure and an ultra-broadband noise attenuation function.

[0006] The object of the present invention is achieved by the following technical solutions.

[0007] A broadband silencer for a fuel cell vehicle comprises a first shell, a second shell, and an internal tube. The first and second shells are connected to form a sealed cavity, and the internal tube is installed within the sealed cavity formed by the first and second shells. The internal tube is provided with holes or grooves, and multiple sound-dampening structures are formed within the sealed cavity. The second shell has a water collection section along its side, and one end of the exhaust port of the internal tube is connected to a venturi tube, with a drain pipe in the center of the venturi tube communicating with the water collection section.

[0008] During operation, the intake end of the first shell of the broadband silencer is connected to the exhaust pipe of the fuel cell stack, and broadband high-frequency noise generated from the fuel cell stack enters the broadband silencer. The silencer structure formed by the shell and the internal tube attenuates the noise energy in the corresponding frequency band, and at the same time, gaseous or liquid water generated by the chemical reactions in the stack also moves through the piping to the silencer. Some of the water enters the chamber of each silencer structure and is eventually carried by gravity to the water collection section where it is collected. In the operating state, as the airflow passes through the tube, a pressure difference is created between the inlet and outlet of the venturi tube located at the end of the internal tube and the center. This pressure difference pushes the water in the water collection section through the drain pipe into the internal tube and discharges it out of the tube along the direction of the airflow. In other words, while silenced, the water generated in the stack is discharged along the tailpipe.

[0009] Furthermore, the water collection section is a rectangular section that penetrates the entire second shell. This allows for the concentrated collection of water flowing into each chamber, thus preventing the silencer chambers from malfunctioning due to water accumulation.

[0010] Furthermore, the second shell is a stepped cylindrical tube, and the internal tube includes a central tube body, on the circumferential wall of the central tube body there are multiple annular partition plates, which are fitted into the stepped cylindrical tube, and after the internal tube is inserted into the second shell, the multiple annular partition plates form multiple sound-dampening chamber structures between themselves and the second shell.

[0011] Furthermore, the soundproofing chamber structure includes one suppressive resonance cavity and two to five preventive resonance cavities.

[0012] Furthermore, near the intake end of the central tube, multiple angular grooves are provided in the circular wall of the central tube, and sound-absorbing cotton is placed on the outside to form a resonant cavity. By quickly replacing the sound-absorbing cotton, silencers with different sound absorption characteristics can be obtained. Depending on the actual acoustic performance requirements and cost requirements, different acoustic performance and cost requirements can be achieved by replacing the sound-absorbing cotton. Since the sound-absorbing cotton itself is waterproof, it will not malfunction due to absorbing liquid water. The sound-absorbing cotton itself can enhance the acoustic performance of the soundproof silencer, and after waterproofing, it can prevent malfunction due to water absorption. Therefore, silencers incorporating sound-absorbing cotton can be used in fuel cells.

[0013] Furthermore, holes are provided in the circular wall of the central tube at positions other than the groove, forming multiple anti-resonance cavities. The opening size and ratio are specially designed according to the actual needs, and a Helmholtz silencer can be formed by a combination of round or elongated holes, wall thickness, and cavities, and multiple different silencers can be connected in series in the axial direction.

[0014] Furthermore, the first shell includes an outer sleeve, which has a bell-mouth shape with a smaller upper end and a larger lower end, and a central intake tube is located inside the outer sleeve.

[0015] The end of the second shell is fixed to the end of the outer sleeve (for example, by screws or welding), and the end of the central inspiratory tube faces the end of the internal tube.

[0016] Furthermore, the lower end of the central intake tube is longer than the outer sleeve, the lower end of the central intake tube is bell-mouth shaped, the upper end of the internal intubation tube is bell-mouth shaped, and the internal intubation tube as a whole is inserted into the second shell. This structure enhances sealing and improves noise reduction and drainage.

[0017] Furthermore, the central intake pipe is equipped with a water separation structure to pre-separate water vapor from the upstream side.

[0018] Furthermore, the water separation structure consists of multiple rotatably arranged blades. The blades rotate the steam flowing in from upstream, and the centrifugal force causes the steam to be blown against the pipe wall. Nozzles are provided on the pipe wall, and the water is discharged through these nozzles.

[0019] Such a broadband silencer integrates a drainage structure and a water separation structure, reducing noise at the exhaust end of a fuel cell while simultaneously achieving a drainage function, thus meeting the exhaust end needs of a fuel cell vehicle. The broadband silencer used in a fuel cell vehicle according to the present invention can cover noise frequencies from 1000Hz to 8000Hz by incorporating the sound-absorbing function of a specific sound-absorbing cotton.

[0020] Compared to existing inventions, the present invention has the following advantages. 1. By incorporating a special drainage structure and a venturi tube into the silencer, a self-draining function during operation can be achieved. 2. A rectangular water collection section, opening on the side of the lower shell, extends throughout the entire silencer, allowing for concentrated collection of water flowing into each chamber, thus preventing each chamber of the silencer from malfunctioning due to water accumulation. 3. By quickly replacing the sound-absorbing cotton, silencers with different sound-absorbing properties can be obtained. Depending on the actual acoustic performance requirements and cost requirements, different acoustic performance and cost requirements can be achieved by replacing the sound-absorbing cotton with different types. 4. Since the sound-absorbing cotton itself is waterproof, it will not malfunction due to absorbing liquid water. The sound-absorbing cotton itself can enhance the acoustic performance of the soundproofing silencer, and after waterproofing, it can prevent malfunction due to water absorption. Therefore, silencers incorporating sound-absorbing cotton can be used in fuel cells. 5. The water separation structure incorporated into the upper shell allows for the pre-separation of water vapor from the upstream. [Brief explanation of the drawing]

[0021] [Figure 1] It is a diagram showing the structure of a wideband muffler. [Figure 2] It is a diagram showing the cross-sectional structure of a wideband muffler. [Figure 3] It is a diagram showing the structure of the first shell. [Figure 4] It is a diagram showing the cross-sectional structure of the first shell. [Figure 5] It is a diagram showing the upper surface structure of the first shell. [Figure 6] It is a diagram showing the structure of the second shell. [Figure 7] It is a diagram showing the structure of the second shell. [Figure 8] It is a diagram showing the cross-sectional structure of the inner insertion tube. [Figure 9] It is a diagram showing the cross-sectional structure of the inner insertion tube. [Figure 10] It is a front view of the sound-absorbing sponge. [Figure 11] It is a cross-sectional view of the sound-absorbing sponge. [Figure 12] It is a top view of the sound-absorbing sponge. [Figure 13] (Results of the transmission loss test of the muffler (using sound-absorbing sponge 1)). [Figure 14] (Results of the transmission loss test of the muffler (using sound-absorbing sponge 2)). [Figure 15] It is a diagram showing the cross-sectional structure of a wideband muffler. [Embodiments for Carrying Out the Invention]

[0022] Hereinafter, the present invention will be described in detail with reference to the drawings and specific embodiments.

[0023] (Embodiment 1) As shown in Figures 1 and 2, a broadband silencer for a fuel cell vehicle comprises a first shell 100, a second shell 200, and an internal tube 300. The first shell 100 and the second shell 200 are connected to form a sealed cavity, and the internal tube 300 is installed within the sealed cavity formed by the first shell 100 and the second shell 200. The internal tube 300 has holes or grooves to form a plurality of sound-dampening structures within the sealed cavity.

[0024] As shown in Figures 6 and 7, the second shell 200 is a stepped cylindrical tube. A water collection section 201 is provided along the side of the second shell 200. The water collection section 201 is a rectangular section that penetrates the entire second shell 200. This allows for the collection of water that flows into each chamber, preventing each chamber of the silencer from malfunctioning due to water accumulation. One end of the exhaust port of the internal tube 300 is connected to a venturi tube 400, and a drain pipe 401 communicating with the water collection section 201 is provided in the center of the venturi tube 400.

[0025] As shown in Figures 8 and 9, the internal tube 300 includes a central tube body. Multiple annular partition plates 301 are provided on the peripheral wall of the central tube body. The annular partition plates 301 are fitted into a stepped cylindrical tube, and after the internal tube 300 is inserted into the second shell 200, multiple sound-dampening chamber structures are formed between the multiple annular partition plates 301 and the second shell 200. The sound-dampening chamber structures include one suppressive resonance cavity and multiple anti-resonance resonance cavities. Near the intake end of the central tube body, multiple square grooves 302 are provided on the circular tube wall of the central tube body, and sound-absorbing cotton 500 is placed on the outside to form suppressive resonance cavities. By quickly replacing the sound-absorbing cotton 500, silencers with different sound absorption characteristics can be obtained.

[0026] Depending on the actual acoustic performance and cost requirements, different acoustic performance and cost requirements can be achieved by replacing the sound-absorbing cotton 500 with different types. Since the sound-absorbing cotton 500 itself is waterproof, it will not malfunction due to absorbing liquid water. The sound-absorbing cotton 500 itself can enhance the acoustic performance of the soundproofing silencer, and after waterproofing, it can prevent malfunction due to water absorption. Therefore, silencers incorporating sound-absorbing cotton 500 can be used in fuel cells.

[0027] The circular wall of the central tube is provided with holes 303 at positions other than the groove, forming multiple anti-resonance cavities. The size and opening ratio of the holes are specially designed according to the actual needs, and a combination of round or elongated holes, wall thickness, and cavities can form a Helmholtz silencer, which can be formed by connecting multiple different silencers in series in the axial direction.

[0028] As shown in Figures 3 to 5, the first shell 100 includes an outer sleeve 101. The outer sleeve 101 has a bell mouth shape with a smaller upper end and a larger lower end. The outer sleeve 101 is equipped with a central intake tube 102. The end of the second shell 200 is fixed to the end of the outer sleeve 101 (for example, connected by screws or welding), and the end of the central intake tube 102 faces the end of the internal tube 300.

[0029] The lower end of the central intake tube 102 is longer than the outer sleeve 101, and the lower end of the central intake tube 102 is bell-mouth shaped. The upper end of the internal tube 300 is also bell-mouth shaped, and the internal tube 300 is integrally inserted into the second shell 200. This structure enhances sealing and improves noise reduction and drainage.

[0030] The central intake pipe 102 is equipped with a water separation structure 103 for pre-separating water vapor from the upstream. The water separation structure 103 consists of multiple rotatably arranged blades. The blades rotate the water vapor flowing in from upstream, and the centrifugal force causes the water vapor to be blown against the pipe wall. A nozzle is provided on the pipe wall, and the water is discharged by the nozzle 104.

[0031] During operation, the intake end of the first shell 100 of the broadband silencer is connected to the exhaust pipe of the fuel cell stack, and broadband high-frequency noise generated from the fuel cell stack enters the broadband silencer. The silencer structure formed by the shell and the internal tube 300 attenuates the noise energy in the corresponding frequency band, and at the same time, gaseous or liquid water generated by the chemical reactions in the stack also moves through the piping to the silencer, with some of the water entering the chambers of each silencer structure and finally flowing by gravity to the water collection section 201 for collection. In the operating state, as the airflow passes through the pipe, a pressure difference is created between the inlet and outlet of the venturi tube 400 located at the end of the internal tube 300 and the center. This pressure difference pushes the water in the water collection section 201 through the drain pipe 401 to the internal tube 300 and discharges it outside the pipe along the direction of the airflow. In other words, while silenced, the water generated in the stack is discharged along the tailpipe.

[0032] (Embodiment 2) In a specific silencer design, sound-absorbing cotton 1 (OX-Pan) is incorporated into the silencer, and sound-absorbing cotton 2 (Basotec G+, manufactured by BASF) is also incorporated into the silencer. The structure of the sound-absorbing cotton is shown in Figures 10 to 12. The specific process parameters for each structure of the silencer are as follows: As shown in Figure 15, C1 has a volume of 0.27L, has a square hole, an opening ratio of 0.66, is used for filling with sound-absorbing cotton, and the functional range of the sound-absorbing cotton is 1000~8000Hz. C2 has a volume of 0.1L, has six round holes with a diameter of 5mm, an opening ratio of 0.014, and the corresponding silencer frequency is 1000Hz. C3 has a volume of 0.044L, has eleven round holes with a diameter of 5mm, an opening ratio of 0.045, and the corresponding silencer frequency is 1120Hz. C4 has a volume of 0.027L, has five circular holes with a diameter of 5mm, an opening ratio of 0.022, and a corresponding silencing frequency of 1420Hz. C5 has a volume of 0.13L, is not perforated, and is used to install the venturi tube 400 and the drain pipe 401.

[0033] Figure 13 shows the transmission loss test results for a silencer using sound-absorbing cotton 1, and Figure 14 shows the transmission loss test results for a silencer using sound-absorbing cotton 2. From these two test results, it can be seen that the silencer with sound-absorbing cotton 1 almost always achieves a transmission loss noise reduction of 20 dB or more in the frequency range of 1300 to 5500 Hz (only up to 5500 Hz can be displayed due to the cutoff frequency of plane waves), and the silencer with sound-absorbing cotton 2 also achieves a transmission loss noise reduction of 15 dB or more in the frequency range of 1300 to 5500 Hz (only up to 5500 Hz can be displayed due to the cutoff frequency of plane waves).

[0034] The above description of embodiments is intended to facilitate understanding and use of the present invention by those skilled in the art. It will be apparent to those skilled in the art that various modifications can be made to these embodiments and the general principles described herein can be applied to other embodiments without requiring creative effort. Therefore, the present invention is not limited to the embodiments described above. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, are included within the scope of protection of the present invention.

Claims

1. A broadband silencer for fuel cell vehicles, It comprises a first shell, a second shell, and an internal tube, The first shell and the second shell are connected to form a sealed cavity, and the internal tube is installed within the sealed cavity. The sealed cavity is divided into several different chambers by the internal intubation, The internal tube is provided with holes or grooves, and a plurality of sound-absorbing structures are formed within the sealed cavity. A broadband silencer comprising a second shell having a water collection section along its side, one end of the exhaust port of the internal tube connected to a venturi tube, and a drain pipe communicating with the water collection section provided in the center of the venturi tube.

2. The broadband silencer for a fuel cell vehicle according to claim 1, wherein the water collection section is a rectangular water collection section that penetrates the entire second shell.

3. The broadband silencer for a fuel cell vehicle according to claim 1, wherein the second shell is a stepped cylindrical tube, the internal tube includes a central tube body, a plurality of annular partition plates are provided on the peripheral wall of the central tube body, the annular partition plates are fitted into the stepped cylindrical tube, and after the internal tube is inserted into the second shell, the plurality of annular partition plates form a plurality of silencer chamber structures between themselves and the second shell.

4. The broadband silencer for a fuel cell vehicle according to claim 3, wherein the silencer chamber structure comprises one suppressive resonance cavity and two to five preventive resonance cavities.

5. The broadband silencer for a fuel cell vehicle according to claim 4, wherein a plurality of angular grooves extending along the circumferential direction of the cylindrical wall of the central tube are provided in the portion of the central tube near the intake end, and sound-absorbing cotton is placed on the outside to form a suppressive resonance cavity.

6. The broadband silencer for a fuel cell vehicle according to claim 5, wherein holes are provided in the circular wall of the central tube body at positions other than the groove, thereby forming a plurality of anti-resonance cavities.

7. The first shell includes an outer sleeve, the outer sleeve having a bell mouth shape with a smaller upper end and a larger lower end, and a central intake tube is located inside the outer sleeve. The broadband silencer for a fuel cell vehicle according to claim 1, wherein the end of the second shell is fixed to the end of the outer sleeve, and the end of the central intake pipe faces the end of the internal inlet pipe.

8. The broadband silencer for a fuel cell vehicle according to claim 7, wherein the lower end of the central intake pipe is longer than the outer sleeve, the lower end of the central intake pipe is bell-mouth shaped, the upper end of the internal intubation tube is bell-mouth shaped, and the internal intubation tube as a whole is inserted into the interior of the second shell.

9. The broadband silencer for a fuel cell vehicle according to claim 7, wherein the central intake pipe is equipped with a water separation structure for pre-separating water vapor from the upstream.

10. The broadband silencer for a fuel cell vehicle according to claim 9, wherein the water separation structure comprises a plurality of rotatably arranged blades.

Images