EP4591376A1

EP4591376A1 - Exhaust system for hydrogen fuel cell vehicle

Info

Publication number: EP4591376A1
Application number: EP23833592.1A
Authority: EP
Inventors: designation of the inventor has not yet been filed The
Original assignee: Mann and Hummel GmbH
Current assignee: Mann and Hummel GmbH
Priority date: 2023-12-12
Filing date: 2023-12-12
Publication date: 2025-07-30
Also published as: CN120476489A; WO2025123209A1

Abstract

An exhaust system (50) for a hydrogen fuel cell vehicle includes a housing (71) including at least one discharge hole (9) disposed in a lower portion of the housing (71) and configured to discharge water, a water separator (5) integrated in the housing (71) and configured to separate water from exhaust gas, and a muffler (60) integrated in the housing (71) and disposed downstream from the water separator (5), the muffler (60) including a cylindrical tube body (7) including a grid side wall and sound absorbing material (6) circumferentially wrapped around the grid side wall.

Description

Exhaust System for Hydrogen Fuel Cell Vehicle

TECHNICAL FIELD

Embodiments relate to a hydrogen fuel cell vehicle, and more specifically to an exhaust system for a hydrogen fuel cell vehicle.

BACKGROUND ART

In general, a fuel cell generates electrical energy by an electrochemical reaction of hydrogen fuel and oxygen. The fuel cell has been studied and developed as a power supply due to an increase in demand for alternative power supplies. Hydrogen fuel cell, as a real "zero-emission, non-polluting" energy source, is one of the main development directions of clean new energy sources in the future.
The fuel cell includes a fuel cell stack for generating electrical energy, a fuel supplying system for supplying the fuel (hydrogen) to the stack, an air supplying system for supplying air to the stack, and related components. Furthermore, the fuel cell is provided with an exhaust system, and the exhaust system is configured to discharge exhaust gas including air and water. The fuel cell may generate high frequency noise such as high-speed air flow sound, and thus a muffler for reducing noise is mounted in the exhaust system. The muffler includes sound absorbing material such as a glass wool, sound attenuation cotton, or the like for reducing noise.
The exhaust gas produced by the reaction of hydrogen and oxygen in a fuel cell contains a large amount of water and moisture. In particular, the moisture is condensed in the muffler, or water condensed in an upstream exhaust system is introduced into the muffler, which often causes water to be collected in a bottom of the muffler. Meanwhile, since the muffler includes the sound absorbing material having a very high hydrous performance, the muffler easily absorbs water and moisture. Thus, the muffler may not consistently maintain its intended sound absorbing capability, and consequently, acoustic performance thereof may decrease. In addition, the water may be frozen in an environmental condition below a temperature of 0℃, thereby causing problems such as a decrease in exhaust performance.
At present, the exhaust system for the hydrogen fuel cell vehicle has limited water separation efficiency, and thus cannot efficiently separate and drain the liquid water in the exhaust gas.
To this end, it is desirable to develop an exhaust system for a hydrogen fuel cell vehicle which will efficiently separate the water in the exhaust gas.

SUMMARY

An object of the present disclosure is to provide an exhaust system for a hydrogen fuel cell vehicle which will efficiently separate the water in the exhaust gas.
Another object of the present disclosure is to provide an exhaust system for a hydrogen fuel cell vehicle which will exhibit optimized flow performance.
In one aspect, an exhaust system for hydrogen fuel cell vehicle is provided. The exhaust system includes:
a housing provided with at least one discharge hole disposed in a lower portion of the housing and configured for discharging water;
a water separator integrated in the housing and configured to separate water from exhaust gas; and
a muffler integrated in the housing and disposed downstream from the water separator, the muffler includes a cylindrical tube body including a grid side wall and sound absorbing material circumferentially wrapped around the grid side wall.
The water separator may include a first cylindrical portion adjacent to an inlet of the exhaust system and a second conical portion adjacent to the muffler, internal diameter of the second conical portion increases in a downstream direction.
The first cylindrical portion may be provided with at least one spiral guide blade configured to rotate the exhaust gas in swirl way to produce centrifugal force, to separate water from the exhaust gas, and the second conical portion (52) may be configured to facilitate water to be thrown onto the interior surface of the housing.
The muffler may further include a guide fitting at the upstream end of the cylindrical tube body.
The guide fitting may include a cylindrical outside surface and a cylindrical interior surface, the cylindrical tube body defining a muffler internal diameter Dm, and the cylindrical interior surface defining an internal diameter Din equal to the muffler internal diameter Dm.
The guide fitting may include a cylindrical outside surface and a conical interior surface, the cylindrical tube body defining a muffler internal diameter Dm, and the conical interior surface defining an inlet internal diameter Din at the upstream end thereof and defining an outlet internal diameter at the downstream end thereof. The inlet internal diameter Din may be greater than the muffler internal diameter Dm, and the outlet internal diameter may be equal to the muffler internal diameter Dm.
The muffler internal diameter Dm may be between 60%to 90%of the inlet internal diameter Din.
The guide fitting may include a length L in a longitudinal direction of the exhaust system which is between 10%to 50%of the muffler internal diameter Dm.
The cylindrical tube body may be provided with a plurality of annular support wall extending outward from the outside surface of the cylindrical tube body and configured to support the muffler in the housing.
The cylindrical tube body may be provided with at least one partition plate extending inward from the interior surface of the cylindrical tube body and configured to separate the internal cavity into a plurality of resonator cavities in a longitudinal direction of the exhaust system.
The water separator may be provided with a plurality of annular support wall extending outward from the outside surface of the water separator and configured to support the water separator in the housing.
The at least one discharge hole may be disposed in the housing at the position adjacent to and downstream from the water separator.
The guide fitting and the cylindrical tube body may be integrated in one-piece, and the water separator, the guide fitting and the cylindrical tube body may be formed of polypropylene.
A valve may be provided in the at least one discharge hole and is configured to control the discharge of the water.
The sound absorbing material may be provided with a waterproof coating at the outside thereof.
By means of the water separator integrated upstream of the muffler to efficiently separate water from the exhaust gas, the muffler may consistently maintain its intended sound absorbing capability, and consequently acoustic performance thereof is excellent. The muffler contains one or more isolated resonator cavities to meet noise reduction requirements.
In addition, the water separator is a centrifugal water separator, which needs no external power supply to generate centrifugal force, thus, the operational cost is saved.
In addition, by means of water-resistant coating at the outside of the sound absorbing material, the muffler may consistently maintain its intended sound absorbing capability.
The main material of the exhaust system is polypropylene (PP) plastic, which is easy to integrate other plastic structures than traditional metal exhaust systems, is light in weight, is low in cost, and does not rust.
By optimizing the flow characteristics in the muffler with the guide fitting, the acoustic damping performance is optimized.
Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.

BRIEF DESCRIPTION OF DRAWINGS

The present disclosure will become more fully understood from the detailed description and the accompanying drawings.
Fig. 1 is a schematic view of an example fuel cell system according to embodiments.
Fig. 2 is a schematic explosive view of an example exhaust system of the fuel cell system according to embodiments.
Fig. 3 schematically illustrates flow-field state of a combination of a water separator and a muffler of the fuel cell system according to embodiments.
Fig. 4 is a schematic view of an example of the combination of the water separator and the muffler without optimized 3D effects according to embodiments, with a housing removed.
Fig. 5 is a schematic view of an example of the combination of the water separator and the resonator with optimized 3D effects according to embodiments, with the housing removed.
Fig. 6 shows acoustic damping characteristics of the combination of the water resonator and the muffler of Fig. 4 and the combination of the water resonator and the muffler of Fig. 5.

DESCRIPTION OF EMBODIMENTS

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. Additionally, the drawings are generally schematic and not necessarily to scale. Some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present disclosure.
Certain terminology may be used in the following description for the purpose of reference only, and thus are not intended to be limiting. For example, terms such as “above” and “below” refer to directions in the drawings to which reference is made. Terms such as “front” , “back” , “fore” , “aft” , “left” , “right” , “rear” , “side” , “upward” , “downward” , “top” , and “bottom” , etc., describe the orientation and/or location of portions of the components or elements within a consistent but arbitrary frame of reference, which is made clear by reference to the text and the associated drawings describing the components or elements under discussion.
Furthermore, terms such as “first” , “second” , “third” , and so on may be used to describe separate components. Such terminology are used descriptively for the figures, and do not represent limitations on the scope of the disclosure, as defined by the appended claims. Moreover, the teachings may be described herein in terms of functional and/or logical block components and/or various processing steps. It should be understood that such block components may include a number of hardware, software, and/or firmware components configured to perform the specified functions.
As used herein, the term “downstream” or "upstream" may be used to indicate a direction with regard to the exhaust gas flow direction.
Referring now to the drawings, wherein like reference numbers refer to like features throughout the several views, Fig. 1 is a schematic view of a fuel cell system 100 according to embodiments; Fig. 2 is a schematic structural explosive view of the fuel cell system 100 according to embodiments.
Fig. 1 is a schematic view of an example fuel cell system 100 according to embodiments. Referring to Fig. 1, the fuel cell system 100 may include a hydrogen supply unit 20, a fuel cell stack 30, an air supply unit 40, and an exhaust system 50.
The hydrogen supply unit 20 may supply hydrogen from a hydrogen tank to the fuel cell stack 30 according to operating conditions of the fuel cell stack 30. After chemical reaction in the fuel cell stack 30, the remainder of the hydrogen may be exhausted through an outlet of a hydrogen electrode (an anode) of the fuel cell stack 30, or be recirculated to an inlet of the hydrogen electrode of the fuel cell stack 30 by a hydrogen recirculation apparatus (not shown) .
The fuel cell stack 30 may generate electrical energy from electrochemical reaction between hydrogen fuel and air including oxygen. The fuel cell stack 30 may include a plurality of fuel cells and a plurality of separators alternately stacked. Each fuel cell may include a cathode, an electrolyte layer and an anode. For example, hydrogen supplied to the anode may be separated into hydrogen ions and electrons, the electrons may be moved to the cathode, and, at the cathode, oxygen may be combined with the electrons and thus produce oxygen ions. The oxygen ions may be moved to the anode through the electrolyte layer and be combined with the hydrogen ions at the anode and thus create a reactant, i.e., water. The fuel cell stack 30 may include a polymer electrolyte membrane fuel cell (PEMFC) , a phosphoric acid fuel cell (PAFC) , an alkaline fuel cell (AFC) , a molten carbonate fuel cell (MCFC) , a solid oxide fuel cell (SOFC) , etc., without departing the scope of the disclosure.
The fuel cell stack 30 may include a purge valve (not shown) to exhaust hydrogen within the hydrogen electrode of the fuel cell stack 30. The purge valve may be opened or closed in a predetermined purge interval. Further, sensors (not shown) may be disposed at the outlet of the anode of the fuel cell stack 30, and the sensors (not shown) may measure pressures applied to hydrogen introduced into the fuel cell stack 30 and hydrogen exhausted from the fuel cell stack after reaction and concentrations thereof. As shall be understood for those skilled in the art, the fuel cell stack 30 may include other components as needed, such as a controller, etc., without departing the scope of the disclosure.
The air supply unit 40 may supply air to the fuel cell stack 30. The fuel cell system 100 may be used in a vehicle, including but are not limited to, a passenger vehicle, sport utility vehicle, light truck, heavy duty vehicle, minivan, bus, transit vehicle, bicycle, moving robot, farm implement (e.g., tractor) , sports-related equipment (e.g., golf cart) , train. As shall be understood for those skilled in the art, the fuel cell system 100 may be used in any other movable or stationary platform, such as a digger, a compressor, a robot, etc., without departing the scope of the disclosure.
Fig. 2 is a schematic explosive view of an example exhaust system of the fuel cell system according to embodiments. The exhaust system 50 may include a housing 71 provided with at least one discharge hole 9 disposed in a lower portion of the housing 71 and configured for discharging water. As shown in Fig. 2, the housing 71 includes an upper cover 4 and a lower housing 10. The at least one discharge hole 9 is disposed at the bottom of the lower housing 10 at the position adjacent to and downstream from the water separator 5. A valve (not shown) may be provided in the at least one discharge hole 9 and is configured to control the discharge of the water. As shall be understood for those skilled in the art, the housing 71 may have other suitable structure, without departing the scope of the disclosure.
The exhaust system 50 may further include a water separator 5 integrated in the housing 71 and configured to separate water from exhaust gas. The exhaust system 50 may further include a muffler 60 integrated in the housing 71 and disposed downstream from the water separator 5. As shown in Fig. 2, the muffler 60 includes a cylindrical tube body 7 including a grid side wall and sound absorbing material 6 circumferentially wrapped around the grid side wall. As shall be understood for those skilled in the art, the muffler 60 may have other suitable structure, without departing the scope of the disclosure.
The exhaust system 50 may further include suitable connecting structures, such as a first connecting adaptor 1, an inlet pipe 2, a second connecting adaptor 3, a third connecting adaptor 11, and an outlet pipe 12. As shall be understood for those skilled in the art, the exhaust system 50 may include any other suitable components, without departing the scope of the disclosure.
Fig. 3 schematically illustrates flow-field state of a combination of the water separator 5 and the muffler 60 of the fuel cell system 100 according to embodiments. Exhaust gas containing water and moisture (as shown in starlike shape) , at first flows into the water separator 5. The water separator 5, under the action of the blade 54, rotates the exhaust gas in cyclonic way to produce centrifugal force, to separate water from the exhaust gas and to throw water (as shown in rectangular shape) to the inner wall of the water separator 5, the water continues to rotate along the inner wall, and finally is thrown out of the water separator to the inner wall of the housing 71. The separated water accumulates in the lower portion of the housing 71, and is discharged through the discharge hole 9 at the bottom of the housing 71. The exhaust gas with water separated flows into the muffler 60 and the noise is attenuated by sound absorbing material in the muffler 60 and the muffler 60 itself.
By means of the centrifugal water separator 5 integrated upstream of the muffler 60 to efficiently separate water from the exhaust gas, the muffler 60 may consistently maintain its intended sound absorbing capability, and consequently acoustic performance thereof is excellent.
In addition, the water separator 5 is shown as a centrifugal water separator, which needs no external power supply to generate centrifugal force, thus, the operational cost is saved. However, as shall be understood for those skilled in the art, the water separator 5 may be any other suitable type, such as membranes, without departing the scope of the disclosure.
As shown in Fig. 2, the muffler 60 is provided with a plurality of annular support wall 14 extending outward from the outside surface of the muffler 60 and configured to support the muffler 60 in the housing 71. Similarly, the water separator 5 is provided with a plurality of annular support wall 13 extending outward from the outside surface of the water separator 5 and configured to support the water separator 5 in the housing 71.
In addition, the muffler 60 is provided with at least one partition plate 8 extending inward from the interior surface of the muffler 60 and configured to separate the internal cavity into a plurality of resonator cavities in a longitudinal direction of the exhaust system 50, so to meet noise reduction requirements.
According to one example, the sound absorbing material 6 is provided with a waterproof coating (not shown) at the outside thereof. By means of water-resistant coating at the outside of the sound absorbing material, the muffler may consistently maintain its intended sound absorbing capability.
Fig. 4 is a schematic view of an example of the combination of the water separator 5 and the muffler 60 without optimized 3D effects according to embodiments, with the housing 71 removed. As shown in Fig. 4, the water separator 5 includes a first cylindrical portion 51 adjacent to an inlet of the exhaust system 50 and a second conical portion 52 adjacent to the muffler 60. The internal diameter of the second conical portion 52 increases in a downstream direction. The first cylindrical portion 51 is provided with at least one spiral guide blade 54 (shown in Fig. 3) configured to rotate the exhaust gas in cyclonic way to produce centrifugal force, to separate water from the exhaust gas and the second conical portion 52 is configured to facilitate water to be thrown onto the interior surface of the housing 71. In addition, the muffler 60 further includes a guide fitting 53 at the upstream end of the cylindrical tube body 7.
According to one example, the guide fitting 53 may include a cylindrical outside surface and a cylindrical interior surface. The cylindrical tube body 7 defines a muffler internal diameter Dm, and the cylindrical interior surface of the guide fitting 53 defines an internal diameter Din equal to the muffler internal diameter Dm.
According to one example, the guide fitting 53 and the cylindrical tube body 7 are integrated in one-piece, and the water separator 5, the guide fitting 53 and the cylindrical tube body 7 are formed of polypropylene. The main material of the exhaust system is polypropylene (PP) plastic, which is easy to integrate other plastic structures than traditional metal exhaust systems, is light in weight, is low in cost, and does not rust. However, as shall be understood for those skilled in the art, the water separator 5, the guide fitting 53 and the cylindrical tube body 7 may be formed of any other suitable material, such as steel or other plastic material, without departing the scope of the disclosure.
Fig. 5 is a schematic view of an example of the combination of the water separator 5 and the muffler 60 with optimized 3D effects according to embodiments, with the housing 71 removed. As shown in Fig. 5, the water separator 5 includes a first cylindrical portion 51 adjacent to an inlet of the exhaust system 50 and a second conical portion 52 adjacent to the muffler 60. The internal diameter of the second conical portion 52 increases in a downstream direction. The first cylindrical portion 51 is provided with at least one spiral guide blade 54 (shown in Fig. 3) configured to rotate the exhaust gas in cyclonic way to produce centrifugal force, to separate water from the exhaust gas and the second conical portion 52 is configured to facilitate water to be thrown onto the interior surface of the housing 71. In addition, the muffler 60 further includes a guide fitting 53 at the upstream end of the cylindrical tube body 7.
As shown in Fig. 5, the guide fitting 53 includes a cylindrical outside surface and a conical interior surface. The cylindrical tube body 7 defines a muffler internal diameter Dm, and the conical interior surface defines an inlet internal diameter Din at the upstream end thereof and defines an outlet internal diameter at the downstream end thereof, the inlet internal diameter Din is greater than the muffler internal diameter Dm, and the outlet internal diameter is equal to the muffler internal diameter Dm. According to one example, the muffler internal diameter Dm is between 60%to 90%of the inlet internal diameter Din.
According to one example, the guide fitting 53 and the cylindrical tube body 7 are integrated in one-piece, and the water separator 5, the guide fitting 53 and the cylindrical tube body 7 are formed of polypropylene. The main material of the exhaust system is polypropylene (PP) plastic, which is easy to integrate other plastic structures than traditional metal exhaust systems, is light in weight, is low in cost, and does not rust. However, as shall be understood for those skilled in the art, the water separator 5, the guide fitting 53 and the cylindrical tube body 7 may be formed of any other suitable material, such as steel or other plastic material, without departing the scope of the disclosure.
As shown in Fig. 5, the guide fitting 53 includes a length L in a longitudinal direction of the exhaust system 50. According to one example, the length L is between 10%to 50%of the muffler internal diameter Dm.
Fig. 6 shows acoustic damping characteristics of the combination of the water separator 5 and the muffler 60 of Fig. 4 and the combination of the water separator 5 and the muffler 60 of Fig. 5. As can be seen from Fig. 6, the exhaust system 50 of Fig. 5 with optimized 3D effects exhibits better acoustic damping characteristics than the exhaust system 50 of Fig. 4 without optimized 3D. By optimizing the flow characteristics in the muffler 60 with the guide fitting 53, the acoustic damping performance is optimized.
Aspects of the present disclosure have been described in detail with reference to the illustrated embodiments; those skilled in the art will recognize, however, that many modifications may be made thereto without departing from the scope of the present disclosure. The present disclosure is not limited to the precise construction and compositions disclosed herein; any and all modifications, changes, and variations apparent from the foregoing descriptions are within the scope of the disclosure as defined by the appended claims. Moreover, the present concepts expressly include any and all combinations and subcombinations of the preceding elements and features.

Claims

An exhaust system (50) for a hydrogen fuel cell vehicle, the exhaust system (50) comprising:

a housing (71) comprising at least one discharge hole (9) disposed in a lower portion of the housing (71) and configured to discharge water;

a water separator (5) integrated in the housing (71) and configured to separate water from exhaust gas; and

a muffler (60) integrated in the housing (71) and disposed downstream from the water separator (5) , the muffler (60) comprising a cylindrical tube body (7) comprising a grid side wall and sound absorbing material (6) circumferentially wrapped around the grid side wall.
The exhaust system (50) according to claim 1, wherein the water separator (5) comprises a first cylindrical portion (51) adjacent to an inlet of the exhaust system (50) , and a second conical portion (52) adjacent to the muffler (60) , an internal diameter of the second conical portion (52) increasing in a downstream direction.
The exhaust system (50) according to claim 2, wherein the first cylindrical portion (51) comprises at least one spiral guide blade (54) configured to rotate the exhaust gas in a cyclonic way to produce centrifugal force, to separate the water from the exhaust gas, and

the second conical portion (52) is configured to facilitate the water to be thrown onto an interior surface of the housing (71) .
The exhaust system (50) according to claim 3, wherein the muffler (60) further comprises a guide fitting (53) at an upstream end of the cylindrical tube body (7) .
The exhaust system (50) according to claim 4, wherein the guide fitting (53) comprises a cylindrical outside surface and a cylindrical interior surface,

the cylindrical tube body (7) has a muffler internal diameter Dm, and

the cylindrical interior surface has an internal diameter Din equal to the muffler internal diameter Dm.
The exhaust system (50) according to claim 4, wherein the guide fitting (53) comprises a cylindrical outside surface and a conical interior surface,

the cylindrical tube body (7) has a muffler internal diameter Dm, and

the conical interior surface has an inlet internal diameter Din at an upstream end of the conical interior surface and has an outlet internal diameter at a downstream end of the conical interior surface, the inlet internal diameter Din being greater than the muffler internal diameter Dm, and the outlet internal diameter being equal to the muffler internal diameter Dm.
The exhaust system (50) according to claim 6, wherein the muffler internal diameter Dm is between 60%to 90%of the inlet internal diameter Din.
The exhaust system (50) according to claim 7, wherein the guide fitting (53) has a length L in a longitudinal direction of the exhaust system (50) that is between 10%to 50%of the muffler internal diameter Dm.
The exhaust system (50) according to any of claims 1 to 8, wherein the cylindrical tube body (7) further comprises a plurality of annular support wall (14) extending outward from an outside surface of the cylindrical tube body (7) and configured to support the muffler (60) in the housing (71) .
The exhaust system (50) according to any of claims 1 to 9, wherein the cylindrical tube body (7) further comprises at least one partition plate (8) extending inward from an interior surface of the cylindrical tube body (7) and configured to separate an internal cavity into a plurality of resonator cavities in a longitudinal direction of the exhaust system (50) .
The exhaust system (50) according to claim any of claims 1 to 10, wherein the water separator (5) comprises a plurality of annular support wall (13) extending outward from an outside surface of the water separator (5) and configured to support the water separator (5) in the housing (71) .
The exhaust system (50) according to any of claims 1 to 11, wherein the at least one discharge hole (9) is disposed in the housing (71) at a position adjacent to and downstream from the water separator (5) .
The exhaust system (50) according to any of claims 4 to 8, wherein the guide fitting (53) and the cylindrical tube body (7) are integrated in one-piece, and

the water separator (5) , the guide fitting (53) and the cylindrical tube body (7) are formed of polypropylene.
The exhaust system (50) according to any of claims 1 to 13, wherein the at least one discharge hole (9) comprises a valve configured to control the discharge of the water.
The exhaust system (50) according to any of claims 1 to 14, wherein the sound absorbing material (6) comprises a waterproof coating at an outside of the sound absorbing material (6) .