JP2007207705A - Silencer for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silencer for a fuel cell in which forming of water film against a through-hole installed at an exhaust gas flow passage is prevented and in which a superior noise suppressing performance can be demonstrated sufficiently. <P>SOLUTION: In this silencer for the fuel cell, against at least either one part of the inner peripheral face part 32 of the through-hole 30 installed at the peripheral wall part 26 of the exhaust gas flow passage 12 in which the exhaust gas of the fuel cell is made to be circulated inside, the opening peripheral edge part of the inner face side of the peripheral wall part 26 in the through-hole 30, and the opening peripheral edge part of the outer face side of the peripheral edge part 26 in the through-hole 30, a projection part 34 and/or a recessed part is installed and positioned at one position or a plurality of positions on the periphery of the inner peripheral face part 32 or the opening peripheral edge part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a silencer for a fuel cell, and more particularly to a silencer for a fuel cell that is improved so that the exhaust noise of exhaust gas discharged from the fuel cell can be silenced more advantageously.

  In recent years, fuel cells that are environmentally friendly and have high power generation efficiency have attracted attention and attempts have been made to use them for various purposes. For example, a fuel cell vehicle using such a fuel cell as a driving source is expected as a next-generation vehicle, and a movement toward practical use is in full swing.

  By the way, in a fuel cell system mounted on such a fuel cell vehicle or the like, in many cases, a silencer is provided in an exhaust system extending from the fuel cell, so that exhaust gas discharged into the atmosphere through the exhaust system can be reduced. Exhaust sound is muted.

  As such a silencer for a fuel cell, a number of small through holes communicating the inside and the outside are formed in the peripheral wall (tube wall) portion of the exhaust gas flow path composed of a part of the exhaust pipe and the like. Further, an outer cylinder member is extrapolated in such an exhaust gas flow path, and a sound absorbing material made of, for example, glass wool is disposed between the exhaust gas flow path and the outer cylinder member. A structure having a structure filled so as to cover the part is generally known (see, for example, Patent Documents 1 and 2 below). In the silencer having such a structure, the exhaust sound of the exhaust gas propagated to the outside of the exhaust gas passage through a large number of through holes is absorbed by the sound absorbing material and silenced.

  In addition, a resonance chamber made up of an airtight air chamber is formed around an exhaust gas passage having a large number of through holes formed in the peripheral wall portion as having a structure separate from such a silencer. There is also known a resonance type silencer that has a structure in which a housing is extrapolated and is configured to silence the exhaust sound of the exhaust gas that has been propagated into the resonance chamber through a large number of through holes. Yes.

  However, as a result of repeated studies by the inventors from various angles regarding the structure of such a conventional silencer, the following points have been clarified.

  That is, as is well known, the exhaust gas of a fuel cell contains a large amount of water and water vapor generated by a chemical reaction in the fuel cell, and the temperature of the exhaust gas is It is not so high at about 80 ° C. Therefore, the generated water generated in and discharged from the fuel cell can flow along the exhaust pipe inner surface without being evaporated, and can flow in the exhaust pipe together with the exhaust gas, and the outside air temperature is low. In this case, the water vapor in the exhaust gas is condensed in the exhaust pipe or the silencer and easily becomes condensed water. This condensed water also travels along the inner surface or outer surface of the exhaust pipe and in the exhaust pipe or the silencer. In the conventional silencer as described above, a water film is formed with water such as generated water and condensed water in a large number of through holes provided in the peripheral wall portion of the exhaust gas flow passage. It becomes like this. Then, each through hole is blocked by such a water film, and the propagation of the exhaust sound into the sound absorbing material and the resonance chamber through the through hole is hindered. As a result, a sufficient silencing effect is obtained. It has been found that it may be difficult to obtain.

JP 2004-139787 A JP 2004-156555 A

  Here, the present invention has been made in the background as described above, and the problem to be solved is the peripheral wall portion of the exhaust gas passage through which the exhaust gas of the fuel cell is circulated. In the silencer for a fuel cell, provided with a plurality of through holes and a silencing means for silencing the exhaust sound transmitted to the outside of the exhaust gas passage through the many through holes. Formation of a water film with respect to each through hole due to moisture flowing together with the exhaust gas is advantageously prevented or suppressed, and the propagation of the exhaust sound to the silencing means through each through hole can be effectively ensured, Therefore, the object is to provide an improved structure so that excellent silencing performance can be sufficiently and stably exhibited.

  And in order to solve this subject, the present inventors first observed how the water film was formed in the through hole in the course of various studies. As a result, water droplets adhere to a plurality of locations on the inner peripheral surface portion of the through hole and the peripheral edge of the opening, and when the water droplets attached to each of these locations come into contact with each other due to surface tension, a water film is formed. It was recognized that it would be done. On the other hand, when it was examined whether there is a difference in the ease of forming a water film due to the difference in the shape of the through holes, the circular through holes were more water-filled than the other through holes. It has been found that the film tends to form relatively easily. Considering from the observation results of the formation process of the water film described above, the circular through-hole is different from, for example, a rectangular through-hole, etc. Because the distance between the two is constant, the water droplets adhering to the inner peripheral surface portion and the opening peripheral edge portion are combined with each other, and a balanced surface tension is stably generated in the entire water droplet. it is conceivable that.

  From the facts as described above, the present inventors combined water droplets adhering to the inner peripheral surface part and the opening peripheral part of the through hole as a countermeasure for preventing or suppressing the formation of a water film on the through hole. It was conceived that a structure capable of breaking the balance of the surface tension of the entire water droplet in the above state was given to the inner peripheral surface portion and the opening peripheral portion of the through holes.

  That is, the present invention has been completed as a result of further earnest research based on such an idea. The gist of the present invention is that it has a cylindrical peripheral wall portion and is an exhaust gas for a fuel cell. Is provided on the peripheral wall portion of the exhaust gas passage so that the inside and the outside of the exhaust gas passage communicate with each other. In the muffler for a fuel cell, comprising: a plurality of through holes to be propagated; and a silencing means for silencing the exhaust sound propagated to the outside of the exhaust gas passage through the plurality of through holes. At least one of an inner peripheral surface portion of the exhaust gas passage, an opening peripheral portion of the through hole in the inner surface of the peripheral wall portion of the exhaust gas passage, and an opening peripheral portion of the through hole in the outer surface of the peripheral wall portion of the exhaust gas passage. For one part, a convex part and / or a concave part In silencers for a fuel cell, characterized in that provided so as to be located in one place or a plurality of locations on the peripheral surface portion and the opening periphery.

  In short, in the muffler for a fuel cell according to the present invention, a convex portion is formed at one or a plurality of locations on the inner peripheral surface portion of the through hole and the inner peripheral surface portion of the through hole on the inner surface and outer surface of the peripheral wall portion of the exhaust gas passage. Because of the formation of recesses and recesses, water droplets that adhere to the areas where the protrusions and recesses are formed and the areas where the protrusions and recesses are not formed, of the peripheral edge and inner peripheral surface of such through holes. The contact area between the peripheral edge and the inner peripheral surface of the through-hole is different from each other, and depending on the size of the contact area, the peripheral edge of the water-drop and the through-hole The interfacial tension between the part and the inner peripheral surface part also has different magnitudes.

  Therefore, in the device of the present invention, in the process of forming the water film for each through hole, the peripheral edge of the opening is attached to the opening peripheral part of the through hole or the formation part or non-formation part of the concave part in the inner peripheral surface part. When water droplets that generate interfacial tension of different sizes come into contact with each other and the inner peripheral surface portion and are bonded together, the surface tension of the combined water droplets becomes extremely unbalanced. In addition, the formation of a water film with respect to the through holes is prevented or suppressed in advance.

  Therefore, in the silencer for a fuel cell according to the present invention as described above, the produced water or the condensed water vapor is generated in the fuel cell, discharged from the fuel cell and allowed to flow together with the exhaust gas in the exhaust gas passage. Even when moisture such as water reaches each through hole through the peripheral wall portion of the exhaust gas flow path, a water film is formed in each through hole by such moisture, and each through hole is formed by the water film. Occlusion can be prevented as much as possible. As a result, the propagation of the exhaust sound to the silencing means through each through hole can be effectively ensured, and thus the excellent silencing performance can be sufficiently and stably exhibited.

Aspects of the Invention

  By the way, the present invention can be suitably implemented at least in various aspects as listed below.

(1) An exhaust gas passage having a cylindrical peripheral wall portion through which the exhaust gas of the fuel cell is circulated, and an inner portion and an outer portion of the exhaust gas passage on the peripheral wall portion of the exhaust gas passage. A plurality of through holes that communicate the exhaust sound of the exhaust gas to the outside, and a muffler that silences the exhaust sound propagated to the outside of the exhaust gas passage through the plurality of through holes In the silencer for a fuel cell comprising the means, an inner peripheral surface portion of the through hole, an opening peripheral edge portion of the through hole in an inner surface of the peripheral wall portion of the exhaust gas flow path, and an exhaust gas flow path A convex portion and / or a concave portion is provided at one or a plurality on the periphery of the inner peripheral surface portion or the opening peripheral edge portion with respect to at least any one portion of the opening peripheral edge portion of the through hole on the outer surface of the peripheral wall portion. A muffler for a fuel cell, which is provided so as to be located at a location.

  In the aspect (1) described above, in the case where the convex portion or the concave portion is formed only on the inner peripheral surface portion of the through hole, for example, the convex portion or the concave portion is provided on the opening peripheral edge portion of the through hole in the inner surface of the peripheral wall portion. The flow of the exhaust gas is disturbed by the generation of noise due to the collision of the exhaust gas that circulates in the exhaust gas flow path with the convex part, or by a part of the exhaust gas flowing into the concave part. Thus, it is possible to avoid the occurrence of abnormal noise. In addition, when the resonance chamber is provided on the outside of the peripheral wall portion as a silencer, the volume in the resonance chamber is increased or decreased by forming a convex portion or a concave portion in the opening peripheral portion of the through hole in the outer surface of the peripheral wall portion, The setting of the resonance frequency is not troublesome. Of these effects, the former effect is also obtained in the case where a convex portion or a concave portion is provided in the opening peripheral portion of the through hole on the outer surface of the peripheral wall portion in addition to or instead of the inner peripheral surface of the through hole. Can be enjoyed advantageously. On the other hand, the latter effect can be advantageously enjoyed even when a convex portion or a concave portion is provided in the opening peripheral edge portion of the through hole in the inner surface of the peripheral wall portion in addition to or instead of the inner peripheral surface of the through hole. .

  In addition, in the aspect (1) described above, in the case where a convex portion or a concave portion is formed only on the peripheral edge portion of the through hole on the inner surface or the outer surface of the peripheral wall portion, the opening area of the through hole is particularly increased by the formation of the convex portion. Without being reduced, it can be advantageously ensured, thereby providing the advantage that the exhaust sound can be more reliably propagated through each through hole to the outside of the exhaust gas flow path. In addition, this effect is obtained when only the concave portion is provided on the inner peripheral surface of the through hole in addition to or in place of at least one of the opening peripheral portions of the through hole in the inner surface or outer surface of the peripheral wall portion. Can also be enjoyed advantageously.

(2) In said aspect (1), while the said convex part has a shape where the area of the cross section perpendicular | vertical to a height direction becomes small gradually as it goes to a front-end | tip part, the said recessed part goes to a bottom part. The cross-sectional area perpendicular to the depth direction has a gradually decreasing area. According to this aspect, when the water droplets adhering to the formation part or non-formation part of the convex part or the concave part in the opening peripheral edge part or the inner peripheral surface part of the through hole come into contact with each other and are combined, Thus, the balance of the surface tension of the water can be further disrupted, whereby the formation of a water film with respect to the through holes can be more effectively prevented or suppressed. As a result, the excellent silencing performance can be more fully and stably exhibited.

(3) In the aspect (1) or the aspect (2) described above, the through hole has a circular shape. According to this aspect, even if the formation position of the convex part and the concave part in the inner peripheral surface part and the opening peripheral part of the through hole is any position on the periphery of the inner peripheral surface part and the opening peripheral part, the combined water droplets as a whole The balance of surface tension can be easily broken. Therefore, the design of the formation position of the convex part and the concave part with respect to the inner peripheral surface part and the opening peripheral part of the through hole becomes easy.

(4) In any one of the modes (1) to (3) described above, the silencer is constituted by a sound absorbing material, and the sound absorbing material is in the exhaust gas flow path. It arrange | positions covering at least one part of the said many through-holes from the outer side. According to this aspect, the exhaust sound can be more reliably propagated into the sound absorbing material through the through hole, and therefore the sound absorbing performance by the sound absorbing material can be more effectively and sufficiently exhibited. It will be.

(5) In the above aspect (4), the entire periphery of the portion where the numerous through holes are formed in the peripheral wall portion of the exhaust gas passage is surrounded by a predetermined distance from the outer surface of the peripheral wall portion A member is extrapolated to the exhaust gas flow path, and the sound absorbing material is disposed in a state of being filled between the surrounding member and the exhaust gas flow path. According to this aspect, it is possible to advantageously prevent a part of the sound absorbing material from scattering or the entire sound absorbing material from dropping off.

  Hereinafter, in order to clarify the present invention more specifically, an embodiment of the present invention will be described in detail with reference to the drawings.

  First, FIG. 1 and FIG. 2 schematically show an embodiment of a fuel cell silencer mounted on a fuel cell vehicle having a structure according to the present invention, in a longitudinal sectional form and a transverse sectional form, respectively. It is shown. As is clear from these drawings, the silencer of the present embodiment includes an outer cylindrical member 10 as a device main body, an inner cylindrical member 12 extending through the outer cylindrical member 10, and an outer cylindrical member 10. It has the sound-absorbing material 14 arrange | positioned and is comprised.

  More specifically, the outer cylindrical member 10 as a whole consists of a large-diameter metal or resin tube having a cylindrical shape with bottoms on both sides, and is attached to the fuel cell vehicle under the condition of being mounted on the vehicle. A cylindrical tube wall 16 extending in the front-rear direction (left-right direction in FIG. 1), a front opening (left opening in FIG. 1) and a rear opening (right side in FIG. 1) of the tube wall 16 The front bottom wall portion 18 and the rear bottom wall portion 20 that respectively close the respective opening portions) are integrally formed. From the following, in order to facilitate understanding of the structure of the silencer according to the present embodiment, for convenience, the front bottom wall portion 18 side is referred to as the front side, and the rear bottom wall portion 20 side is referred to as the rear side. I will say.

  In the outer cylindrical member 10, a front through hole 22 penetrating the front bottom wall portion 18 is provided in a substantially central portion of the front bottom wall portion 18 so as to have a large-diameter circular shape. A rear through hole 24 penetrating through the center 20 of the portion 20 is provided coaxially with a circular shape having substantially the same size as the front through hole 22 of the front bottom wall portion 18.

  On the other hand, the inner cylindrical member 12 has an outer diameter that can be inserted into the front and rear through holes 22 and 24 of the outer cylindrical member 10 and a length (high height) that is longer than the outer cylindrical member 10 by a predetermined dimension. It is composed of a metal or resin tube having a cylindrical peripheral wall portion 26.

  And such an inner side cylinder member 12 is inserted in the front side and rear side through-holes 22 and 24 of the outer side cylinder member 10 in the both end part site | part of the length direction, with respect to the outer side cylinder member 10 It is positioned so as to extend through the same axis on the same axis. Further, under such an arrangement state, both end portions in the length direction of the inner cylindrical member 12, that is, the front end portion and the rear end portion of the peripheral wall portion 26 are the front side and the rear side of the front side and rear side bottom wall portions 18, 20. Through the side through holes 22, 24, the both sides of the inner cylinder member 12 are projected forward and rearward from the outer cylinder member 10 toward the front and rear of the outer cylinder member 10. Each is opened. In other words, the outer cylindrical member 10 is spaced apart from the inner cylindrical member 12 by a predetermined distance between the entire circumference of the intermediate portion in the longitudinal direction of the peripheral wall portion 26 and the outer peripheral surface of the intermediate portion of the peripheral wall portion 26. It is extrapolated in a surrounding state.

  The inner cylindrical member 12 is inserted into the front and rear through holes 22 and 24 of the peripheral wall portion 26 with respect to the front bottom wall portion 18 and the rear bottom wall portion 20 of the outer cylindrical member 10, respectively. For example, it is integrally joined by adhesion, welding, welding, or the like, thereby ensuring airtightness between the outer peripheral surface of the peripheral wall portion 26 and the inner peripheral surfaces of the front and rear through holes 22 and 24. Under the state, the inner cylindrical member 12 is fixed to the outer cylindrical member 10.

  The inner cylinder member 12 extends from a fuel cell (not shown) and is connected to an exhaust pipe 28 through which exhaust gas discharged from the fuel cell is circulated so as to be positioned at an intermediate portion thereof. That is, here, the exhaust pipe 28 is divided into two parts: an upstream exhaust pipe 28a that constitutes an upstream portion in the exhaust gas flow direction and a downstream exhaust pipe 28b that constitutes a downstream portion in the exhaust gas flow direction. Has a structured. And, the exhaust gas flow direction downstream end portion of the upstream exhaust pipe 28a and the front end portion of the peripheral wall portion 26 of the inner cylindrical member 12 projected forward from the front bottom wall portion 18 of the outer cylindrical member 10, The opening end faces are abutted against each other and connected in a communicating state. Further, the upstream end portion of the downstream exhaust pipe 28b in the exhaust gas flow direction and the rear end portion of the peripheral wall portion 26 protruded rearward from the rear bottom wall portion 20 of the outer cylindrical member 10 are at the opening end surfaces. They are butted together and connected in communication. As a result, the inner cylinder member 12 is positioned in the middle so as to constitute a part of the exhaust pipe 28, and the exhaust gas discharged from the fuel cell is shown in FIG. The inside of the member 12 can be circulated from the front end side toward the rear end side. As is clear from this, in the present embodiment, the exhaust gas flow path is configured by the inner cylindrical member 12, and the surrounding member is configured by the outer cylindrical member 10 that surrounds the inner cylindrical member 12. Yes.

  In such an inner cylindrical member 12, a large number of small through holes 30 are formed in the peripheral wall portion 26 of the intermediate portion in the length direction positioned inside the outer cylindrical member 10. Each of the large number of through holes 30 has a circular shape and penetrates the peripheral wall portion 26 at the intermediate portion in the longitudinal direction of the inner cylinder member 12, and the outer space located outside the inner space of the inner cylinder member 12. It has a structure that allows the internal space of the tubular member 10 to communicate with each other. And it is located in a line at equal intervals in the axial direction at each of the circumferentially spaced portions in the circumferential wall portion 26 of the intermediate portion in the longitudinal direction of the inner cylindrical member 12 at equal intervals in the axial direction. Yes.

  In addition, the sound absorbing material 14 is positioned inside the outer cylindrical member 10 in which the middle portion in the longitudinal direction of the inner cylindrical member 12 having such a large number of through holes 30 is disposed. Yes. The sound absorbing material 14 as a whole has a substantially thick cylindrical shape having a smaller diameter than the outer cylindrical member 10 and having an inner hole larger in diameter than the inner cylindrical member 12. The type and structure of the sound absorbing material 14 are not limited in any way, and any conventionally known material is used. Here, for example, a fiber aggregate such as stainless wool or glass wool, or an open cell in the interior is used. The thing of the material which has air permeability, such as the communicating porous body in which many were provided, is used.

  Then, such a sound absorbing material 14 is provided on the peripheral wall portion 26 so as to surround the entire outer peripheral surface of the peripheral wall portion 26 at the intermediate portion in the longitudinal direction of the inner cylindrical member 12 disposed inside the outer cylindrical member 10. The plurality of through holes 30 are positioned so as to cover all from the outside. In other words, the inner surface of the outer cylindrical member 10 (the inner surfaces of the cylindrical wall portion 16, the front bottom wall portion 18, and the rear bottom wall portion 20) and the inner cylindrical member 12 disposed inside the outer cylindrical member 10. The sound absorbing material 14 is filled between the outer peripheral surface of the peripheral wall portion 26 at the intermediate portion in the length direction.

  Thus, in the silencer of this embodiment, the exhaust sound of the exhaust gas circulated in the exhaust pipe 28, specifically, for example, the fluid sound generated when the exhaust gas flows through the exhaust pipe 28 at a high speed, A pulsating sound or the like generated when air is intermittently supplied to the fuel cell using a compressor that is not used is provided on the peripheral wall portion 26 at the intermediate portion in the longitudinal direction of the inner cylindrical member 12 disposed inside the outer cylindrical member 10. The sound is transmitted to the sound absorbing material 14 through a large number of through holes 30, and can be silenced or reduced by the sound absorbing material 14. As apparent from this, the sound absorbing material 14 constitutes a sound deadening means.

  By the way, in the silencer of this embodiment having such a structure, a special structure that is not found in the conventional apparatus is given to the inner cylindrical member 12 in particular.

  That is, in such a silencer, as shown in FIG. 3, two convex portions 34 are provided on the inner peripheral surface portion 32 of each of the many through holes 30 provided in the peripheral wall portion 26 of the inner cylindrical member 12. They are integrally formed independently of each other. Both of the two convex portions 34 have the same shape such that the area of the cross section perpendicular to the height direction becomes gradually smaller toward the tip portion. Specifically, it has a concave curved surface configuration having a curvature larger than that of the inner peripheral surface portion 32 portion of the non-formed portion of the convex portion 34, and includes two side surfaces continuous to the inner peripheral surface portion 32 portion and a pointed tip portion. It has a mountain-like overall shape. And such a convex part 34 protrudes toward the center of the through-hole 30 in two places on the circumference located opposite to the radial direction in the inner peripheral surface part 32 of each through-hole 30, and the tip part One piece is formed on each straight line so that the centers of the through holes 30 are located.

  The inner cylindrical member 12 provided with the through holes 30 having a plurality of convex portions 34 on the inner peripheral surface portion 32 uses, for example, a punch having a plurality of concave portions corresponding to the shape of the convex portions 34 on the outer peripheral surface. Then, a punching process is performed on the flat metal plate material to form a plurality of through holes 30 provided with a plurality of convex portions 34 on the inner peripheral surface portion of the metal plate material. It can be easily obtained by forming into a tubular shape or a tubular shape by a technique. Further, when the inner cylindrical member 12 is formed of a resin material, for example, after performing a known extrusion molding or injection molding to form a cylindrical intermediate molded product, a cylindrical wall portion of the intermediate molded product is formed. On the other hand, the through-hole 30 having the convex portion 34 on the inner peripheral surface portion 32 is formed by cutting or the like, whereby the intended inner cylindrical member 12 is produced.

  As described above, in the silencer of the present embodiment, the inner peripheral surface portions 32 of the numerous through holes 30 that are provided on the peripheral wall portion 26 of the inner cylindrical member 12 and allow the exhaust sound to propagate inside the sound absorbing material 14. Convex portions 34 are integrally formed independently at each other at two locations on the circumference of each. Therefore, the generated water (discharged water) generated by the chemical reaction in the fuel cell and discharged from the fuel cell together with the exhaust gas or the condensed water vapor becomes water droplets, for example, the inner circumference of each through hole 30. When the surface portion 32 is attached to the formation portion and the non-formation portion of the convex portion 34, the contact area of the water droplet attached to the convex portion 34 formation portion with the inner peripheral surface portion 32 is attached to the convex portion 34 non-formation portion. It is made larger than the contact area of the water droplet with the inner peripheral surface portion 32. Thereby, the interfacial tension generated between the convex portion 34 forming portion of the inner peripheral surface portion 32 and the water droplet is made larger than the interfacial tension generated between the convex portion 34 non-forming portion of the inner peripheral surface portion 32 and the water droplet.

  Therefore, when the water droplets adhering to the projecting portion 34 formation site and the water droplets adhering to the non-projecting portion 34 forming site in the inner peripheral surface portion 32 of such a through hole 30 are brought into contact with each other and combined. The surface tension of the entire combined water droplets becomes extremely unbalanced, whereby the formation of a water film with respect to the through hole 30 is prevented or suppressed in advance.

  Therefore, in the silencer of the present embodiment as described above, moisture such as generated water or condensed water of water vapor that is generated in the fuel cell, discharged from there, and allowed to flow in the exhaust pipe 28 together with the exhaust gas. However, it reaches the inner peripheral surface portion 32 of each through hole 30 through the tube wall of the exhaust pipe 28 and further the peripheral wall portion 26 of the inner cylindrical member 12, and reaches several locations on the periphery of the inner peripheral surface portion 32. Even if it adheres as a water droplet, a water film is formed in each through-hole 30 by the coupling | bonding of such water droplets, and each through-hole 30 is obstruct | occluded with this water film as much as possible. Can be prevented. As a result, the propagation of the exhaust sound into the sound absorbing material 14 through each through-hole 30 can be effectively ensured, so that the exhaust sound is sufficiently and stably silenced by the sound absorbing material 14. Or it can be reduced.

  In such a silencer, the convex portion 34 is provided only on the inner peripheral surface portion 32 of each through hole 30 in the inner cylindrical member 12, and the convex portion 34 is provided on the inner peripheral surface of the inner cylindrical member 12. It can be advantageously avoided that the exhaust gas circulated in the inner cylindrical member 12 collides with the convex portion 34 or the like inside the inner cylindrical member 12 to generate abnormal noise.

  Furthermore, in the silencer of the present embodiment, the convex portion 34 has a mountain shape with a sharp tip, and is configured such that the area of a cross section perpendicular to the height direction gradually decreases toward the tip portion. Therefore, when the water droplets adhering to the formation part or non-formation part of the convex part 34 in the inner peripheral surface part 30 of each through-hole 30 are in contact with each other and bonded together, the balance of the surface tension in the whole combined water drop is Therefore, the formation of the water film with respect to the through hole 30 can be more effectively prevented or suppressed.

  In addition, in the silencer of the present embodiment, since the sound absorbing material 14 is disposed so as to be filled between the inner cylindrical member 12 and the outer cylindrical member 10, the entire sound absorbing material 14 is disposed inside them. It is in a state surrounded by the cylindrical member 12 and the outer cylindrical member 10, whereby a part of the sound absorbing material 14 is scattered or the entire sound absorbing material 14 is dropped, so that the sound deadening performance is impaired. This can be effectively prevented.

  Next, FIG. 4 shows another embodiment in which the structure of the inner cylinder member 12 is partially different from that of the silencer according to the embodiment shown in FIGS. Only shown. In addition, regarding the embodiment shown in FIG. 4 and FIGS. 5 to 9 which will be described later, the same reference numerals as those in FIGS. Detailed description thereof is omitted.

  That is, as apparent from FIG. 4, in the silencer of the present embodiment, there are four open peripheral portions 36 a of the through holes 30 on the outer surface (upper surface in FIG. 4) of the peripheral wall portion 26 of the inner cylindrical member 12. The convex portions 38 are integrally formed independently of each other. In addition, four convex portions 38 are integrally formed independently of each other on the opening peripheral edge portion 36b of each through hole 30 on the inner surface (the lower surface in FIG. 4) of the peripheral wall portion 26 of the inner cylindrical member 12. . Each of the convex portions 38 has a triangular pyramid shape as a whole, and is configured such that the cross-sectional area perpendicular to the height direction gradually decreases toward the tip portion.

  And such convex part 38 is four places on the circumference located with a 90-degree phase difference in the peripheral direction among the opening peripheral parts 36a of each through-hole 30 on the outer surface of the peripheral wall part 26, and the opening peripheral part. Corresponding to the four locations on the inner surface of the peripheral wall portion 26 corresponding to the four locations on the circumference of 36a on the circumference of the opening peripheral edge portion 36b of each through-hole 30 with the center of the through-hole 30 interposed therebetween One to be formed is formed so as to face each other.

  In addition, when forming the convex part 38 in the opening peripheral part 36a, 36b of each through-hole 30, for example, the convex part 38 is separately molded by a member separate from the inner cylindrical member 12, A technique is adopted in which the peripheral edge portions 36a and 36b of each through hole 30 are integrated by adhesion, welding, welding, or the like. Further, when the inner cylindrical member 12 is made of metal, for example, the opening peripheral edge 36 of each through hole 30 protrudes to the inner surface side or the outer surface side of the inner cylindrical member 12 at one or a plurality of locations on the circumference. By bending and deforming as described above, the convex portions 38 can be formed on the opening peripheral portions 36 a and 36 b of the through holes 30. Further, when the inner cylindrical member 12 is made of resin, an intermediate molded body having the convex portions 38 integrally formed on the outer surface is formed by, for example, injection molding or the like, and then the positions where the convex portions 38 are formed are opened. By forming the through hole 30 by cutting or the like so as to be the peripheral edge 36 a, the convex portion 38 may be formed on the opening peripheral edge 36 a of the through hole 30.

  Thus, even in the silencer of the present embodiment, convex portions are provided at four locations on the circumferences of the opening peripheral edge portions 36a and 36b of the through holes 30 on the outer surface and the inner surface of the peripheral wall portion 26 of the inner cylindrical member 12. The portions 38 are integrally formed independently of each other. Therefore, the generated water or the condensed water of water vapor that is allowed to flow along with the exhaust gas in the exhaust pipe 28 is the formation part and non-formation part of the projections 38 in the opening peripheral parts 36a and 36b of the respective through holes 30 or the respective through holes. The opening peripheral edge of each through-hole 30 when adhering as a water drop to a portion of the inner peripheral surface portion 32 of the opening peripheral portion 36a, 36b that continues to the convex portion 38 forming portion and the convex portion 38 non-forming portion. Interfacial tension generated between the projections 38 forming portions on the portions 36 a and 36 b and the inner peripheral surface portion 30 and water droplets adhering thereto, and the convex portions 38 on the opening peripheral portions 36 a and 36 b of the respective through holes 30 and the inner peripheral surface portion 30. The interfacial tension generated between the non-formed site and the water droplet adhering to the non-formed site becomes different from each other.

  Therefore, also in the silencer of this embodiment, the same actions and effects as those of the first embodiment can be enjoyed effectively.

  And, in the present embodiment, in particular, the convex portion 38 is provided only on the opening peripheral portions 36a, 36b of the through holes 30 on the outer surface and the inner surface of the peripheral wall portion 26 of the inner cylindrical member 12, For example, unlike the embodiment in which the convex portion 34 is provided on the inner peripheral surface portion 30 of each through hole 30, the formation of the convex portion 38 makes it possible to reduce the opening area of each through hole 30. Thus, the exhaust sound can be more sufficiently and reliably transmitted through the through holes 30 into the sound absorbing material 14. As a result, even better silencing performance can be advantageously exhibited.

  Moreover, in the silencer of this embodiment, the convex part 38 has the opening peripheral part 36a of each through-hole 30 in the outer surface of the surrounding wall part 26 of the inner side cylinder member 12, and the opening peripheral part 36b of each through-hole 30 in the inner surface. Both are provided at positions corresponding to each other in the circumferential direction. Therefore, when the convex part 38 is provided only in any one of the opening peripheral part 36a of each through-hole 30 in the outer surface of the surrounding wall part 26, and the opening peripheral part 36b of each through-hole 30 in the inner surface of the surrounding wall part 26. In comparison, the difference between the contact area of the water droplets adhering to the convex 38 formation site and the contact area of the water droplets adhering to the non-projection 38 formation site is different The interfacial tension generated between the convex portion 38 forming portion and the water droplet adhering thereto is advantageously increased, and the interfacial tension generated between the convex portion 38 non-forming portion and the water droplet adhering thereto. The difference between them can also be advantageously increased. Therefore, the formation of a water film with respect to the through hole 30 can be more effectively prevented or suppressed.

  Next, FIG. 5 shows another embodiment in which the structure of the inner cylindrical member 12 is partially different from the silencer according to the two embodiments, only in a part of the inner cylindrical member 12. ing.

  That is, in the silencer of this embodiment shown in FIG. 5, the four concave portions 40 are formed independently of each other on the inner peripheral surface portion 32 of each through hole 30. All of these four concave portions 40 have the same shape such that the area of the cross section perpendicular to the depth direction gradually decreases toward the bottom portion. Specifically, a cross-sectional V-shape that extends in the axial direction of the through hole 30 (a direction perpendicular to the radial direction), opens at the inner peripheral surface portion 32, and also opens at the inner surface and the outer surface of the peripheral wall portion 26, respectively. It is configured with a groove or cut shape. Then, one such recess 40 is formed at each of four locations on the circumference, which are positioned with a phase difference of 90 ° in the circumferential direction, of the inner circumferential surface portion 32 of each through hole 30.

  The inner cylindrical member 12 provided with the through hole 30 having such a recess 40 is, for example, a flat metal plate using a punch or the like having a plurality of protrusions corresponding to the shape of the recess 40 on the outer peripheral surface. After punching the material and forming a large number of through holes 30 having an inner peripheral surface portion 32 provided with a plurality of recesses 40 in the metal plate material, this is formed into a tubular shape by a known method. This can be easily obtained. Further, when the inner cylindrical member 12 is formed of a resin material, for example, after performing a known extrusion molding or injection molding to form a cylindrical intermediate molded product, a cylindrical wall portion of the intermediate molded product is formed. On the other hand, the through-hole 30 having a plurality of recesses 40 in the inner peripheral surface portion 32 is formed by cutting or the like, whereby the intended inner cylindrical member 12 is produced.

  Thus, in the silencer of this embodiment, the groove-shaped recessed part 40 extended in an axial direction is provided in four places on the circumference in the inner peripheral surface part 32 of each through-hole 30, respectively. Therefore, when the generated water or the condensed water vapor that is allowed to flow along with the exhaust gas in the exhaust pipe 28 adheres as water droplets to the formation part and the non-formation part of the recess 40 in the inner peripheral surface part 32 of each through hole 30, Based on the difference in the contact area of each water droplet with the inner peripheral surface portion 32, the interfacial tension generated between the recessed portion 40 forming portion and the water droplet adhering thereto and between the portion where the recessed portion 40 is not formed and the water droplet adhering thereto are generated. The interfacial tension becomes different from each other.

  Therefore, in the silencer of this embodiment as described above, as in the two embodiments, the formation of a water film on each through hole 30 is prevented as much as possible, and the sound absorbing material 14 through each through hole 30 is prevented. Propagation of exhaust sound to the inside can be effectively ensured, so that the excellent effect that the exhaust sound can be sufficiently and stably silenced or reduced by the sound absorbing material 14 is sufficiently enjoyed. Can be done.

  Further, in the silencer of the present embodiment, in particular, the formation of a plurality of recesses 40 in the inner peripheral surface portion 32 of each through hole 30 can prevent the water film with respect to each through hole 30. Therefore, without reducing the opening area of each through-hole 30, and without disturbing the flow of the exhaust gas flowing through the inner cylindrical member 12 and generating abnormal noise, as described above. Excellent actions and effects can be secured stably.

  Furthermore, in such a silencer, unlike the case where the convex portions (34, 38) are formed on the inner peripheral surface portion and the opening peripheral edge portions 36a, 36b of each through hole 30, the water film formation preventing effect due to the deformation of the convex portions is achieved. There is no fear of causing a decrease or the like.

  Next, FIG. 6 shows another embodiment in which the structure of the inner cylinder member 12 is partially different from the silencer according to the three embodiments, only in a part of the inner cylinder member 12. ing.

  That is, as apparent from FIG. 6, in the silencer of the present embodiment, four open peripheral portions 36 a of the through holes 30 on the outer surface (upper surface in FIG. 6) of the peripheral wall portion 26 of the inner cylindrical member 12 are provided. The recesses 42 are formed independently of each other. In addition, four recesses 42 are formed independently of each other on the opening peripheral edge 36b of each through hole 30 on the inner surface (the lower surface in FIG. 6) of the peripheral wall portion 26 of the inner cylindrical member 12. Each of the concave portions 42 has two triangular side surfaces extending obliquely so as to approach the opposite side to the center side of the through-hole 30, and in the depth direction toward the bottom portion. It is configured with a recess shape with a V-shaped cross section so that the area of the cross section at right angles becomes gradually smaller.

  And such a recessed part 42 is four places on the periphery located in the circumferential direction with a 90-degree phase difference among the opening peripheral part 36a of each through-hole 30 in the outer surface of the surrounding wall part 26, and this opening peripheral part 36a. Corresponding to the four locations on the inner periphery of the peripheral wall portion 26 and corresponding to the four locations on the periphery of the opening peripheral edge portion 36b of each through hole 30 in the radial direction with the center of the through hole 30 in between. Each one is formed so as to be opposed to each other, and the corner portions formed by the inner peripheral surface portion 32 of the through hole 30 and the upper surface and the lower surface of the peripheral wall portion 26 that are continuous with each other are removed. ing.

  In addition, when forming the recessed part 42 in the opening peripheral part 36a, 36b of each through-hole 30, for example, a flat plate using a punch having a cylindrical outer peripheral surface corresponding to the inner peripheral surface part 32 of the through-hole 30 is used. After punching a metal plate material to form a large number of through holes 30 in the metal plate material, the peripheral edge portions 36a and 36b of the through holes 30 are partially cut or crushed. Then, the recess 42 is formed in the opening peripheral edge portions 36a and 36b, and thereafter, the metal plate material is easily formed into a tubular shape by a known method. Further, when the inner cylindrical member 12 is formed of a resin material, for example, after performing a known extrusion molding or injection molding to form a cylindrical intermediate molded product, a cylindrical wall portion of the intermediate molded product is formed. On the other hand, the through-holes 30 having a plurality of recesses 42 in the opening peripheral edge portions 36a and 36b are formed by cutting or the like, whereby the intended inner cylindrical member 12 is produced.

  As described above, in the silencer of the present embodiment, the concave portions 42 are provided at four locations on the circumferences of the opening peripheral edge portions 36 a and 36 b of the through holes 30 on the outer surface and the inner surface of the peripheral wall portion 26 of the inner cylindrical member 12. Are formed independently of each other. Therefore, when water droplets composed of generated water or condensed water vapor that is allowed to flow in the exhaust pipe 28 together with the exhaust gas adhere to the opening peripheral edge portions 36 a and 36 b and the inner peripheral surface portion 32 of the respective through holes 30, the respective through holes are provided. 30 in the opening peripheral portions 36a and 36b and the inner peripheral surface portion 30 of the inner peripheral surface portion 32, the interfacial tension generated between the portion where the concave portion 42 is formed in the inner peripheral surface portion 32 and the water droplets adhering thereto. The interfacial tension generated between the portion where the recess 42 is not formed and the water droplet adhering to the portion is different from each other.

  Therefore, even in the silencer of this embodiment, the same actions and effects as those of the three embodiments can be enjoyed effectively.

  Here, in order to confirm that the effects as described above can be obtained by providing concave portions and convex portions on the inner peripheral surface portion and the opening peripheral portion of the through-hole, the tests conducted by the present inventors will be described in detail. .

  That is, first, one flat plate made of vinyl chloride resin and having a thickness of 1 mm was prepared. Then, 20 circular through-holes having a diameter of 6 mm were formed on the flat plate at a predetermined interval from each other. Then, 10 through holes are selected from the 20 through holes, and a V-shaped concave portion having a depth of 1 mm is formed on each inner peripheral surface portion of the selected 10 through holes. Four pieces were formed by cutting. These four recesses are positioned independently at four locations on the circumference of the inner circumferential surface portion of each through hole that are located with a phase difference of 90 ° in the circumferential direction. did.

  Next, a flat plate provided with 10 through holes in which four concave portions are formed in the inner peripheral surface portion and ten through holes having no such concave portions in the inner peripheral surface portion and a spray spray are used. With the flat plate positioned horizontally, water was sprayed evenly over the entire surface of the flat plate by spraying from a position 100 mm away from the surface. After that, out of the 10 through holes provided with the recesses in the inner peripheral surface portion, the number of the through holes in which the water film is formed and the 10 through holes in which no recess is provided in the inner peripheral surface portion Then, the number of through holes in which a water film was formed was examined. And the test which performs a series of operation which investigates the number of the through-hole in which the spray of the water with respect to such a flat plate and the water film was formed was repeated 5 times.

  As a result, among the 10 through holes in which no recess is provided on the inner peripheral surface portion, the number of through holes in which the water film is formed is 2 in each of the tests from the first to the fifth. The average ratio of the number of through-holes formed with water films to the 10 through-holes was 32%. On the other hand, among the ten through holes provided with four recesses in the inner peripheral surface portion, the number of through holes in which the water film was formed was 1 in each of the first to fifth tests. The average of the ratio of the number of through holes in which the water film was formed with respect to the 10 through holes was 18%. From these test results, it is recognized that the formation of a water film with respect to the through hole can be clearly suppressed by providing a plurality of recesses in the inner peripheral surface portion of the through hole.

  The specific configuration of the present invention has been described in detail above. However, this is merely an example, and the present invention is not limited by the above description.

  For example, the number of the protrusions 34 and 38 and the recesses 40 and 42 provided on the inner peripheral surface portion 32 and the opening peripheral edge portions 36a and 36b of each through hole 30 is not limited to the illustrated one. It may be individual or plural, depending on the size of each of the convex portions 34, 38 and the concave portions 40, 42, the size of the inner peripheral surface portion 32, or the opening peripheral edge portions 36a, 36b, etc. It is determined appropriately.

  Further, the arrangement positions of the convex portions 34 and 38 and the concave portions 40 and 42 are not particularly limited as long as they are located on the inner peripheral surface portion 32 and the opening peripheral edge portions 36a and 36b.

  Further, for example, as shown in FIGS. 7 and 8, only the convex portions 34 and 38 are provided on both the inner peripheral surface portion 32 and the opening peripheral edge portions 36a and 36b of one through hole 30, or the concave portion is provided. Only 40 and 42 may be provided.

  Further, for example, as shown in FIG. 9, the projections 34 and 38 and the recesses 40 and 42 are variously combined with respect to both the inner peripheral surface portion 32 and the opening peripheral edge portions 36 a and 36 b of one through hole 30. There is no problem even if it is provided. Furthermore, another convex portion 38 provided on the opening peripheral edge portion 36 of the through hole 30 can be formed with respect to the convex portion 34 provided on the inner peripheral surface portion 32 of the through hole 30. Furthermore, only the convex portions 34 and 38 or only the concave portions 40 and 42 may be provided for both the inner peripheral surface portion 32 and the opening peripheral edge portions 36 a and 36 b of one through hole 30.

  Although not shown in the drawings, at least one of the convex portion and the concave portion is defined as an inner peripheral surface portion, an outer peripheral edge portion on the outer peripheral surface portion of the one through hole, and an outer peripheral edge portion on the inner peripheral side of the peripheral wall portion. Even if it is provided only in any one of the parts, there is no problem. In addition, even when providing a convex part and a recessed part in both the outer peripheral part of the surrounding wall part in one through-hole, and the opening peripheral part on the inner surface side, the formation position of a convex part or a recessed part is the opening of the peripheral wall part outer surface and inner surface side It is not always necessary to set the position corresponding to the circumferential direction in both of the peripheral portions.

  Further, at least one of the convex portion and the concave portion is provided only on both the inner peripheral surface portion of one through hole and the opening peripheral portion on the outer surface side of the peripheral wall portion, or the inner peripheral surface portion and the peripheral wall in one through hole. You may provide only in both the opening peripheral parts of a part inner surface side.

  Furthermore, both the convex portion and the concave portion may be provided only on both the outer peripheral side of the peripheral wall portion and the inner peripheral portion of the opening in one through hole.

  In addition, it is not absolutely necessary for all the many through holes to be the same in the formation structure of the convex portions and the concave portions (the shape and forming position of the convex portions and the concave portions, the number of formed portions, etc.). Even if all or some of them are configured to be different from each other in the formation structure of the convex portion and the concave portion, there is no problem.

  Needless to say, the shape and size of such convex portions and concave portions are not limited to those shown in the above embodiments.

  In the above embodiment, the exhaust gas flow path is constituted by the inner cylindrical member 12 connected in the middle of the exhaust pipe 28. However, a plurality of through holes 30 are provided in a part of the tube wall of the exhaust pipe 28. Thus, an exhaust gas flow path can also be formed at the site where the through hole 30 of the exhaust pipe 28 is formed.

  Furthermore, in the said embodiment, although the muffling means was comprised by the sound-absorbing material 14 extrapolated by the inner side cylinder member 12 as an exhaust gas flow path, a resonance chamber was made around the exhaust gas flow path, It may be formed in a known structure, and the silencer may be configured in this resonance chamber. Further, when the sound deadening means is constituted by the sound absorbing material 14, the outer cylindrical member 10 as the surrounding member can be omitted. Even when the surrounding member is provided, the shape, size, and the like are not particularly limited.

  In addition, the present invention can be similarly applied to any of the fuel cell silencer used in various applications in addition to the fuel cell silencer mounted on the fuel cell vehicle. Of course.

  In addition, although not enumerated one by one, the present invention can be carried out in a mode to which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art. It goes without saying that all are included in the scope of the present invention without departing from the spirit of the present invention.

It is a vertical explanatory view showing one embodiment of a silencer for a fuel cell according to the present invention. It is II-II sectional explanatory drawing in FIG. FIG. 2 is an enlarged perspective view illustrating a part of an exhaust gas passage in the fuel cell silencer shown in FIG. 1, and shows a structure of a through hole formed in the exhaust gas passage. It is a figure corresponding to FIG. 3 in another example of the silencer for fuel cells according to this invention. It is a figure corresponding to FIG. 3 in another example of the silencer for fuel cells according to this invention. It is a figure corresponding to Drawing 3 in other examples of a silencer for fuel cells according to the present invention. It is a figure corresponding to FIG. 3 in the further another example of the silencer for fuel cells according to this invention. It is a figure corresponding to FIG. 3 in another example of the silencer for fuel cells according to this invention. It is a figure corresponding to FIG. 3 in another example of the silencer for fuel cells according to this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Outer cylinder member 12 Inner cylinder member 14 Sound absorption material 26 Peripheral wall part 28 Exhaust pipe 30 Through-hole 32 Inner peripheral surface part 34,38 Convex part 36 Opening peripheral part 40,42 Concave part

Claims (5)

An exhaust gas passage having a cylindrical peripheral wall portion through which the exhaust gas of the fuel cell is circulated, and the inside and outside of the exhaust gas passage communicate with the peripheral wall portion of the exhaust gas passage A plurality of through holes for propagating the exhaust sound of the exhaust gas to the outside, and a silencing means for silencing the exhaust sound propagated to the outside of the exhaust gas passage through the plurality of through holes. In a silencer for a fuel cell configured to include:
Of the inner peripheral surface portion of the through hole, the opening peripheral portion of the through hole in the inner surface of the peripheral wall portion of the exhaust gas flow channel, and the opening peripheral portion of the through hole in the outer surface of the peripheral wall portion of the exhaust gas flow channel A fuel cell, wherein at least one portion is provided with a convex portion and / or a concave portion so as to be located at one or a plurality of locations on the circumference of the inner peripheral surface portion and the peripheral edge portion of the opening. Silencer for use.   The convex portion has a shape in which the area of the cross section perpendicular to the height direction gradually decreases as it goes to the tip portion, and the area of the cross section perpendicular to the depth direction increases as the concave portion goes to the bottom portion. The muffler for a fuel cell according to claim 1, which has a gradually decreasing shape.   The silencer for a fuel cell according to claim 1 or 2, wherein the through hole has a circular shape.   The sound-absorbing means is constituted by a sound-absorbing material, and the sound-absorbing material is disposed so as to cover at least a part of the plurality of through holes from the outside with respect to the exhaust gas passage. The muffler for a fuel cell according to any one of claims 3 to 4. An enclosing member that surrounds the entire circumference of the portion where the plurality of through holes are formed in the peripheral wall portion of the exhaust gas passage with a predetermined distance from the outer surface of the peripheral wall portion is extrapolated to the exhaust gas passage. 5. The silencer for a fuel cell according to claim 4, wherein the sound absorbing material is disposed in a state of being filled between the surrounding member and the exhaust gas flow path.

Images