JP3776080B2

JP3776080B2 - Silencer for fuel cell

Info

Publication number: JP3776080B2
Application number: JP2002324130A
Authority: JP
Inventors: 鐵雄後藤; 和男小寺
Original assignee: NIHON GLASS FIBER INDUSTRIAL CO., LTD.
Current assignee: NIHON GLASS FIBER INDUSTRIAL CO., LTD.
Priority date: 2002-11-07
Filing date: 2002-11-07
Publication date: 2006-05-17
Anticipated expiration: 2022-11-07
Also published as: JP2004156555A

Description

【０００１】
【発明の属する技術分野】
本発明は、燃料電池の排気管に設けられる消音器に関するものである。
【０００２】
【従来の技術】
従来の自動車用消音器は、排気管の一部に多数の通気孔を貫設し、該排気管の一部の外周に吸音材としてのグラスウールを配設し、その外周に金属よりなる外管を被せてなるものが一般的である。また、排気管とグラスウールとの間に金属繊維よりなる飛散防止層を設け、グラスウールの熱劣化及び飛散を防止したものもある。また、吸音材としてのグラスウール自体をステンレス鋼繊維等の金属繊維で置き換えることも検討されている。これらは、勿論、内燃機関からの排気管に設けるものとして開発されてきた。
【０００３】
ところで、内燃機関式自動車の代替技術の一つとして、燃料電池からの電流によりモータを作動させて車輪を駆動する、いわゆる燃料電池車の実用化が近付いている。燃料電池は水の電気分解の逆反応を利用した発電デバイスであり、二つの電極にそれぞれ水素と酸素とを供給して電気化学反応（前記逆反応）を起こさせ、同電極から外部に電流を取り出すが、同反応により生ずる水蒸気が排気ガスとして排出される。前述した吸音材としてグラスウール又はステンレス鋼繊維を用いた消音器は、この燃料電池からの排気管に設けることもできるが、その際に新たに留意すべき点は前記水蒸気による吸音材の含水である。消音器筐体内の底部には前記水蒸気の結露により水が溜まるため、この底部に溜まった水が毛細管現象により吸い上げられ、吸音材全体に含水状態となりやすい。吸音材が含水すると、吸音材の繊維間の空隙（空気層）が無くなるため、吸音性能が低下する。
【０００４】
しかるところ、最近、消音器筐体の内部空間を連通孔を有する仕切板により上側の室と下側の室とに区画し、上側の室にグラスウールを充填することによりグラスウールの含水を防止するようにした燃料電池車の消音器が公開された（特開２００２−２０６４１３公報）。
【０００５】
【特許文献１】
特開２００２−２０６４１３公報
【０００６】
【発明が解決しようとする課題】
燃料電池からの排気管に設けられる消音器及びその吸音材には、次の課題がある。
（１）自動車のリサイクル率の向上のため、吸音材もリサイクル可能なものとする。
（２）自動車の燃費向上のため、吸音材の重量当たりの吸音性（重量効率）を高くして、吸音材を軽量化する。
（３）前記のとおり、吸音材の含水を防止する必要がある。
前記グラスウールを用いた消音器は、軽量性は良いが、リサイクル性が悪い。また、水はけが悪いため、燃料電池に用いると、含水して吸音性能が低下しやすい。そこで、前記公開公報の公知例のように消音器筐体の内部空間を区画する等して対策する必要があるが、そうすると、消音器の構造が複雑になり、コストアップとなってしまう。また、前記ステンレス鋼繊維を用いた消音器は、リサイクル性は良いが、軽量性が良くない。
【０００７】
本発明の目的は、排気ガスが水蒸気である環境下で、水はけが良く、長期にわたり良好な吸音性能を維持することができ、かつ軽量でリサイクルが可能な燃料電池からの排気管に設けられる消音器及びその吸音材を提供することにある。
【０００８】
【課題を解決するための手段】
燃料電池には色々な種類があり、反応温度で分類すると、反応温度が３００℃以下の低温形とそれ以上の高温型とに分類できる。主に有機繊維を用いる本発明を適用できるのは、その耐熱性の点で、反応温度が３００℃以下の低温形燃料電池である。かかる低温形燃料電池としては、現時点では、固体高分子型（ＰＥＦＣ）、アルカリ形（ＡＦＣ）、リン酸形（ＰＡＦＣ）の各燃料電池を例示できる。
【０００９】
（１）第１の発明は、排気ガスが水蒸気であり反応温度が３００℃以下である低温形燃料電池からの排気管に配される消音器であって、排水孔を設けた消音器筐体と、該消音器筐体の内部空間の少なくとも一部に充填した、主にクリンプを有する有機繊維を用いて嵩密度２０〜２００ｋｇ／ｍ³ に調整した吸音材とを含み、前記嵩密度の調整により前記吸音材の水はけを良くするとともに、前記吸音材内部を透水した水を前記排水孔から前記消音器の外に排水するようにした燃料電池用消音器である。
（２）第２の発明は、排気ガスが水蒸気であり反応温度が３００℃以下である低温形燃料電池からの排気管に配される消音器であって、排水孔を設けた消音器筐体と、該消音器筐体の内部空間の少なくとも一部に充填した、主に撥水処理を施した有機繊維を用いて嵩密度２０〜２００ｋｇ／ｍ³ に調整した吸音材とを含み、前記嵩密度の調整と前記撥水処理とにより前記吸音材の水はけを良くするとともに、前記吸音材内部を透水した水を前記排水孔から前記消音器の外に排水するようにした燃料電池用消音器である。
（３）第３の発明は、排気ガスが水蒸気であり反応温度が３００℃以下である低温形燃料電池からの排気管に配される消音器であって、排水孔を設けた消音器筐体と、該消音器筐体の内部空間の少なくとも一部に充填した、主にクリンプを有するとともに撥水処理を施した有機繊維を用いて嵩密度２０〜２００ｋｇ／ｍ ³ に調整した吸音材とを含み、前記嵩密度の調整と前記撥水処理とにより前記吸音材の水はけを良くするとともに、前記吸音材内部を透水した水を前記排水孔から前記消音器の外に排水するようにした燃料電池用消音器である。
（４）第４の発明は、排気ガスが水蒸気であり反応温度が３００℃以下である低温形燃料電池からの排気管に配される消音器であって、排水孔を設けた消音器筐体と、該消音器筐体の内部空間の少なくとも一部に充填した、主に有機繊維をフェルト状とした板状、棒状又はブロック状の要素を、少なくとも一部の要素間接合面が内周から外周方向に向かうように接合することにより、筒状に形成するとともに嵩密度２０〜２００ｋｇ／ｍ³ に調整した吸音材とを含み、前記嵩密度の調整と前記要素間接合面とにより前記吸音材の水はけを良くするとともに、前記吸音材内部を透水した水を前記排水孔から消音器の外に排水するようにした燃料電池用消音器である。
ここで、同嵩密度の調整値は、消音器筐体の内部空間への充填時における値である。
「有機繊維」の種類は、特に限定されない。「主に有機繊維」とは、繊維に有機又は無機のバインダーを混合し、保型性を高めることで充填しやすくさせる場合も含む意味である。この場合、バインダー量が多いと、繊維の接着点の数が増して強度は上がるが、吸音性能は低下するため、出来るだけ少なくするのが望ましい。
嵩密度２０ｋｇ／ｍ³ 未満では、グラスウール並みの吸音性能を付与することができない。嵩密度２００ｋｇ／ｍ³ を越えた場合は、毛細管現象による含水が著しく生じ、水はけが悪く、吸音性能が低下する。嵩密度はさらに好ましくは３５〜５０ｋｇ／ｍ³ である。
【００１０】
有機繊維としては、ポリプロピレン（ＰＰ）、ポリエチレン（ＰＥ）、ポリエチレンテレフタレート（ＰＥＴ）、レーヨン、ビニロン、ナイロン、ポリエステル、ポリ塩化ビニール、アクリル、ビニリデン及びアセテートの合成繊維、並びに麻、綿、やし、竹、羊毛及び絹の天然繊維から選ばれる少なくとも一種からなる繊維を例示することができる。
コスト、耐含水性、汎用性から、ポリプロピレン、ポリエチレン、ポリエチレンテレフタレートが好ましい。これらの繊維を複数混綿しても良いが、リサイクルの面で１種類の材質で使用する方が好ましい。
天然繊維を使用する場合は、繊維自身に吸水性があるので、前述した第２の発明を適用し撥水処理を施すことが好ましい。
【００１１】
有機繊維が、平均繊維径３〜２７μｍとする繊維であることが好ましい。
平均繊維径が３μｍ未満では、調達が困難となりコストが著しく高くなる。平均繊維径が２７μｍを超えた場合は、吸音性能の低下が著しい。平均繊維径はコスト面と吸音性能を考慮すると、１０〜１８μｍがより望ましい。
【００１２】
第１及び第３の発明では、クリンプを有する繊維とすることで、繊維間の空隙が歪曲やくびれを有する状態となり、空気の粘性摩擦抵抗が増大し、吸音性能を良くすることができる。
【００１３】
第２及び第３の発明の撥水処理に用いる撥水剤としては、特に限定されないが、フッ素系化合物やシリコーン系（オイル、エマルジョン等）を例示でき、繊維表面に施すことで、水はけをさらに良くすることができる。
【００１４】
第４の発明では、板状、棒状、ブロック状等の要素を、合わせ面を内周から外周に向かって積層することで、繊維間に含水した水分が排気ガスの流圧と微振動にて合わせ面に沿って吹き出すことができ、より有効に排水することができる。
【００１５】
上記各発明で、「排気管」は排気が通り消音器を構成する管であれば特に限定されず、燃料電池から延出する排気管や、該排気管に連結された消音器筐体の内部仕切板に設けられたインナーパイプ等を例示できる。吸音材は、その全体が前記有機繊維の吸音材よりなるものが望ましい。
また、吸音材の設け方としては、特に限定されないが、フェルト状の有機繊維を長い帯状にし排気管の外周に巻き付ける方法や、前記第４の発明のような筒状のものを排気管の外周に形成する方法を例示できる。または、多数の細孔が開いたフィルムを予め消音器の形状に作っておき、その中へフェルト状の有機繊維を挿入し、入口を封止する方法も例示できる。また、有機繊維を圧縮空気で解繊しながら直接消音器筐体内に充填する方法も適用できる。
【００１６】
消音器筐体の少なくとも一部（例えば下部）に排水孔を設けることにより、燃料電池から排気ガスである水蒸気が吸音材に拡散し水が下部に溜まったとしても、排ガス流により吸音材内部を透水した水を適度に消音器の外に排水することができる。排水孔の開口面積を微小にすることで、吸音性能の低下を抑制できる。また、排水性を高めるため、消音器筐体内面または吸音材外面に、排水用の溝を任意に設けても良く、吸音材の固定支持を兼ねたスペーサを消音器筐体と吸音材の間に挿入し、適度な空気層を設けても良い。
【００１７】
【発明の実施の形態】
以下、本発明を具体化した消音器の実施形態について説明する。なお、実施形態で記す材料、構成、数値等は例示であって、適宜変更できる。
（試験１）
実施例１として、繊維径１７．５μｍ・繊維長５０ｍｍのポリプロピレン繊維を用い、クリンプがないものとクリンプがあるもの（図４（ａ）にクリンプがある繊維１０を示す。）とをそれぞれニードルパンチでフェルト状とし、嵩密度３５、５０、１００ｋｇ／ｍ³ に調整した吸音材を作成した。また、比較例１として、Ｅガラス繊維を用い、同様にニードルパンチにて嵩密度１００ｋｇ／ｍ³ に調整した吸音材を作成した。これら実施例１及び比較例１の各吸音材からＪＩＳ−Ａ−１４０５に規定される厚さ１０ｍｍの円板形状の試験片を作成し、管内法による垂直入射吸音率測定法に従って各周波数における吸音率を測定した。表１にその測定結果を示す。
【００１８】
【表１】

【００１９】
（試験２）
実施例２として、繊維径が１１．５μｍから２７．１μｍまで異なるレーヨン繊維を用い、それぞれニードルパンチでフェルト状とし、嵩密度５０ｋｇ／ｍ³ に調整した吸音材を作成した。また、比較例２として、平均繊維径２４μｍのガラス長繊維（オーウェンスコーニングジャパン社の商品名；Advantex（アドバンテックス））を用いて、同様にニードルパンチにて嵩密度１００ｋｇ／ｍ³ に調整した吸音材を作成した。これら実施例２及び比較例２の各吸音材からＪＩＳ−Ａ−１４０５に規定される厚さ１０ｍｍの円板形状の試験片を作成し、管内法による垂直入射吸音率測定法に従って各周波数における吸音率を測定した。表２にその測定結果を示す（前記比較例１の測定結果も併記する）。
【００２０】
【表２】

【００２１】
（試験３）
次に、実施例１及び比較例１の各吸音材について、透水性試験を行った。試料サイズは、直径９１．５ｍｍ×厚さ１０ｍｍの円板とした。同試験は、大気中で室温の条件にて、水中浸漬後、円板の側面を一箇所持ち上げ、垂直方向に２分間の水切りをして取出し、増加重量を求めた。
【００２２】
【表３】

【００２３】
（試験４）
同様に、実施例３及び比較例３として、実施例１及び比較例１の各吸音材に撥水剤で表面処理を施したものを作成し、透水性試験を行った。撥水剤としては、シリコーン系撥水剤（東レダウコーニングシリコーン社の商品名；ＳＭ８７０６）を用いて含浸塗布し、絞り後、乾燥した。含浸量を調整することで、乾燥後の重量を測り、ねらいとする嵩密度を求めた。試料サイズは、直径９１．５ｍｍ×厚さ１０ｍｍの円板とした。同試験は、大気中で室温の条件にて、水中浸漬後、円板の側面を一箇所持ち上げ、垂直方向に２分間の水切りをして取出し、増加重量を求めた。
【００２４】
【表４】

【００２５】
以上のとおり、実施例の吸音材によれば、次の作用効果が得られる。
［１］表１に示す測定結果のとおり、実施例１の吸音材は、軽量な有機繊維を用いているにも拘わらず、ガラス繊維を用いた比較例１の吸音材と略同等の吸音性能を有する。特に、１０００Ｈｚ以下の周波数域にて吸音性能が優れている。
［２］表２に示す測定結果のとおり、実施例２の吸音材は、繊維径が太めの有機繊維を用いているにも拘わらず、太めのガラス長繊維を用いた比較例２の吸音材に対し同等以上の吸音性能を有する。特に、１０００Ｈｚ以下の周波数域にて吸音性能が優れている。
［３］表３に示すとおり、実施例１の吸音材は、ガラス繊維と比較し、良好な透水性を示している。
［４］表４に示すとおり、実施例３の撥水剤で繊維に表面処理を施した吸音材は、良好な透水性を示している。
【００２６】
次に、図１〜図３に示すように、燃料電池車の燃料電池の排気管１（インナーパイプ）であって多数の小孔２を貫通させた箇所の外周に、実施例１〜３のフェルト状の各吸音材を、長い帯１１（例えば帯幅２０〜１００mm、帯厚１〜１０mm）にまとめて排気管１の外周に複数重にぐるぐる巻きする方法により巻き付けて、全体がこの吸音材からなる吸音材３を構成した。その後、外径φ８９×内径φ８７×全長２９８ｍｍのアルミメッキ鋼管製の消音器筐体４（アウターパイプ）を外挿し、排気管１と消音器筐体４との当接部の隙間を溶接し、消音器を完成させた。消音器筐体４の内部空間には各吸音材が充填されたことになる。消音器筐体４の少なくとも一部には排水孔１５を貫設した。この消音器は、排気ガスが水蒸気である環境下で、水はけが良く、長期にわたり良好な吸音性能を維持することができた。
【００２７】
また、実施例１〜３のフェルト状の各吸音材を、図４（ｂ）に示すように板状の要素１２に形成したり、図４（ｃ）に示すように棒状の要素１３に形成したりしたものを、少なくとも一部の要素間接合面が内周から外周方向に向かうように接合することにより筒状の吸音材３に形成した。この吸音材３についても、前記燃料電池車の燃料電池の排気管１に配される消音器筐体４の内部空間に充填して、消音器を完成させた。この消音器は、さらに水はけが良く、長期にわたり良好な吸音性能を維持することができた。
【００２８】
なお、本発明は上記実施形態に限定されるものではなく、発明の趣旨から逸脱しない範囲で適宜変更して具体化することもできる。
【００２９】
【発明の効果】
以上詳述したように、本発明に係る燃料電池用消音器によれば、排気ガスが水蒸気である環境下で、水はけが良く、長期にわたり良好な吸音性能を維持することができ、かつ軽量でリサイクルも可能であるという優れた効果を奏する。
【図面の簡単な説明】
【図１】本発明の実施形態の消音器を一部破断して示す斜視図である。
【図２】同消音器を一部破断して示す断面図である。
【図３】同消音器の吸音材形成時の斜視図である。
【図４】（ａ）は同消音器に用いる吸音材のクリンプを有する有機繊維を示す拡大図、（ｂ）は吸音材の別例を示す斜視図、（ｃ）は吸音材の他の別例を示す斜視図である。
【符号の説明】
１排気管
２小孔
３吸音層
４消音器筐体
１０有機繊維
１１帯
１２要素
１３要素
１５排水孔[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a muffler provided in an exhaust pipe of the fuel cell.
[0002]
[Prior art]
A conventional automobile silencer has a large number of ventilation holes penetrating a part of an exhaust pipe, glass wool as a sound absorbing material is disposed on the outer periphery of a part of the exhaust pipe, and an outer pipe made of metal on the outer periphery. What is covered is generally. In addition, there is a type in which a scattering prevention layer made of metal fibers is provided between the exhaust pipe and the glass wool to prevent thermal deterioration and scattering of the glass wool. Further, replacement of glass wool itself as a sound absorbing material with metal fibers such as stainless steel fibers has also been studied. These have, of course, been developed to be provided in exhaust pipes from internal combustion engines.
[0003]
By the way, as one of the alternative technologies of the internal combustion engine type automobile, a so-called fuel cell vehicle, which drives a wheel by operating a motor by a current from a fuel cell, is approaching. A fuel cell is a power generation device that uses the reverse reaction of water electrolysis. Hydrogen and oxygen are supplied to two electrodes to cause an electrochemical reaction (the reverse reaction), and an electric current is sent from the electrode to the outside. Although it is taken out, water vapor generated by the reaction is exhausted as exhaust gas. The silencer using glass wool or stainless steel fiber as the sound absorbing material described above can also be provided in the exhaust pipe from this fuel cell, but in that case, a new point to be noted is the water content of the sound absorbing material by the water vapor. . Since water accumulates at the bottom of the silencer housing due to the condensation of the water vapor, the water accumulated at the bottom is sucked up by a capillary phenomenon, and the entire sound absorbing material tends to be in a water-containing state. When the sound-absorbing material contains water, since there are no voids (air layers) between the fibers of the sound-absorbing material, the sound absorbing performance decreases.
[0004]
However, recently, the inner space of the silencer housing is partitioned into an upper chamber and a lower chamber by a partition plate having a communication hole, and glass wool is prevented from being contained by filling the upper chamber with glass wool. A silencer for a fuel cell vehicle is disclosed (Japanese Patent Laid-Open No. 2002-206413).
[0005]
[Patent Document 1]
JP-A-2002-206413 [0006]
[Problems to be solved by the invention]
The silencer provided in the exhaust pipe from the fuel cell and the sound absorbing material have the following problems.
(1) In order to improve the recycling rate of automobiles, sound absorbing materials shall be recyclable.
(2) To improve the fuel efficiency of automobiles, the sound absorbing material (weight efficiency) per weight of the sound absorbing material is increased to reduce the weight of the sound absorbing material.
(3) As described above, it is necessary to prevent moisture absorption of the sound absorbing material.
The silencer using the glass wool has good lightness but poor recyclability. Moreover, due to poor drainage, the use in fuel cells, sound absorbing performance tends to lower in water. Therefore, it is necessary to take measures by partitioning the internal space of the silencer housing as in the publicly known example of the above publication, but doing so complicates the structure of the silencer and increases costs. Moreover, the silencer using the stainless steel fibers is good in recyclability but not in light weight.
[0007]
It is an object of the present invention to provide a muffler provided in an exhaust pipe from a fuel cell that can be drained, maintained a good sound absorption performance over a long period of time in an environment where the exhaust gas is water vapor, and is lightweight and recyclable. It is in providing a container and its sound-absorbing material.
[0008]
[Means for Solving the Problems]
There are various types of fuel cells, which can be classified into a low-temperature type with a reaction temperature of 300 ° C. or lower and a high-temperature type with a higher reaction temperature. Mainly to the present invention can be applied using an organic fiber, its in terms of heat resistance, a low temperature type fuel cells of the reaction temperature is 300 ° C. or less. Examples of such low-temperature fuel cells are currently polymer electrolyte (PEFC), alkaline (AFC), and phosphoric acid (PAFC) fuel cells.
[0009]
(1) A first invention is a silencer disposed in an exhaust pipe from a low-temperature fuel cell whose exhaust gas is water vapor and a reaction temperature is 300 ° C. or less, and is provided with a drainage hole And a sound- absorbing material adjusted to a bulk density of 20 to 200 kg / m ³ using organic fibers mainly having a crimp filled in at least a part of the inner space of the silencer housing, and adjusting the bulk density Thus, the noise absorber for the fuel cell is configured to improve drainage of the sound absorbing material and drain water that has permeated through the inside of the sound absorbing material from the drain hole to the outside of the silencer .
(2) The second invention is a silencer disposed in an exhaust pipe from a low-temperature fuel cell whose exhaust gas is water vapor and the reaction temperature is 300 ° C. or less, and is provided with a drainage hole And a sound absorbing material filled in at least a part of the interior space of the silencer housing and adjusted to a bulk density of 20 to 200 kg / m ³ using organic fibers mainly subjected to water repellent treatment, A silencer for a fuel cell that improves drainage of the sound absorbing material by adjusting the density and the water repellent treatment, and drains water that has permeated through the sound absorbing material from the drain hole to the outside of the silencer. is there.
(3) A third invention is a silencer disposed in an exhaust pipe from a low-temperature fuel cell in which the exhaust gas is water vapor and the reaction temperature is 300 ° C. or less, and is provided with a drain hole And a bulk density of 20 to 200 kg / m ³ using organic fibers mainly filled with crimp and water-repellent, filled in at least a part of the interior space of the silencer housing. The sound absorbing material is adjusted to the above, and the drainage of the sound absorbing material is improved by adjusting the bulk density and the water repellent treatment, and water that has permeated the inside of the sound absorbing material is removed from the drain hole to the outside of the silencer. This is a silencer for a fuel cell that drains water .
(4) A fourth invention is a silencer disposed in an exhaust pipe from a low-temperature fuel cell in which the exhaust gas is water vapor and the reaction temperature is 300 ° C. or less, and the silencer housing provided with a drain hole And a plate-like, rod-like or block-like element mainly filled with felt made of organic fibers filled in at least a part of the inner space of the silencer housing , and at least a part of the joint surface between the elements from the inner periphery The sound absorbing material includes a sound absorbing material that is formed in a cylindrical shape and is adjusted to a bulk density of 20 to 200 kg / m ³ by joining so as to face in the outer circumferential direction, and the sound absorbing material is adjusted by the adjustment of the bulk density and the joint surface between the elements. The fuel cell silencer is configured to improve drainage of water and drain water from the inside of the sound absorbing material through the drain hole to the outside of the silencer .
Here, the adjustment value of the same bulk density is a value at the time of filling the inner space of the silencer housing.
The type of “organic fiber” is not particularly limited. The “mainly organic fiber” is meant to include a case where an organic or inorganic binder is mixed into the fiber and the shape retention is improved to facilitate filling. In this case, if the amount of the binder is large, the number of adhesion points of the fibers is increased and the strength is increased, but the sound absorption performance is lowered.
If the bulk density is less than 20 kg / m ³ , the sound absorption performance equivalent to that of glass wool cannot be provided. When the bulk density exceeds 200 kg / m ³ , water content due to capillary action is remarkably generated, water drainage is poor, and sound absorption performance is deteriorated. The bulk density is more preferably 35 to 50 kg / m ³ .
[0010]
As organic fibers , polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), rayon, vinylon, nylon, polyester, polyvinyl chloride, acrylic, vinylidene and acetate synthetic fibers, hemp, cotton, palm, Examples thereof include at least one fiber selected from bamboo, wool and silk natural fibers.
Polypropylene, polyethylene, and polyethylene terephthalate are preferable from the viewpoints of cost, water resistance, and versatility. A plurality of these fibers may be mixed, but it is preferable to use one kind of material in terms of recycling.
When natural fibers are used, since the fibers themselves have water absorption, it is preferable to apply the water repellent treatment by applying the second invention described above .
[0011]
Organic fibers, it is preferred that fibers with an average fiber diameter 3～27Myuemu.
If the average fiber diameter is less than 3 μm, procurement is difficult and the cost is significantly increased. When the average fiber diameter exceeds 27 μm, the sound absorption performance is significantly reduced. The average fiber diameter is more preferably 10 to 18 μm in consideration of cost and sound absorption performance.
[0012]
In the first and third inventions, the fibers having crimps are in a state where the gaps between the fibers are distorted and constricted, the viscous frictional resistance of air is increased, and the sound absorbing performance can be improved.
[0013]
The water repellent used in the water repellent treatment of the second and third inventions is not particularly limited, but fluorine compounds and silicones (oils, emulsions, etc.) can be exemplified. Can be better.
[0014]
In the fourth invention, by laminating elements such as a plate shape, a rod shape, and a block shape from the inner periphery toward the outer periphery, the moisture contained between the fibers is caused by the exhaust gas flow pressure and slight vibration. It can blow out along a mating surface, and can drain more effectively.
[0015]
In each of the above-described inventions , the “exhaust pipe” is not particularly limited as long as the exhaust passes through and constitutes a silencer. The exhaust pipe extending from the fuel cell and the interior of the silencer housing connected to the exhaust pipe Examples include an inner pipe provided on the partition plate. The sound absorbing material is preferably made entirely of the organic fiber sound absorbing material.
In addition, the method of providing the sound absorbing material is not particularly limited, but a method of winding felt-like organic fibers into a long belt shape and winding it around the outer periphery of the exhaust pipe, or a cylindrical thing like the fourth invention is used as the outer periphery of the exhaust pipe. The method of forming can be illustrated. Alternatively, a method in which a film having a large number of pores is made in the shape of a silencer in advance, a felt-like organic fiber is inserted therein, and the inlet is sealed can be exemplified. Further, Ru can be applied a method of directly filled into the silencer housing with fibrillating organic fibers with compressed air.
[0016]
By providing drain holes in at least a part of the Mute device housing (e.g. bottom), as water vapor from the fuel cell is an exhaust gas diffused water collected in the lower sound absorbing material, the internal sound absorbing material by the exhaust gas stream Water that has passed through can be drained out of the silencer appropriately. Decreasing the sound absorption performance can be suppressed by reducing the opening area of the drain hole. In addition, in order to improve drainage, a drainage groove may be optionally provided on the inner surface of the silencer housing or the outer surface of the sound absorbing material, and a spacer that also serves as a fixing support for the sound absorbing material is provided between the silencer housing and the sound absorbing material. A suitable air layer may be provided.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a silencer embodying the present invention will be described below. Note that the materials, configurations, numerical values, and the like described in the embodiments are examples and can be appropriately changed.
(Test 1)
As Example 1, polypropylene fibers having a fiber diameter of 17.5 μm and a fiber length of 50 mm are used, and needle punches each without crimps and those with crimps (fiber 10 with crimps is shown in FIG. 4A) are respectively used. Thus, a sound-absorbing material having a felt shape and adjusted to a bulk density of 35, 50, and 100 kg / m ³ was prepared. Moreover, as Comparative Example 1, a sound-absorbing material was prepared using E glass fiber and similarly adjusted to a bulk density of 100 kg / m ³ with a needle punch. A disk-shaped test piece having a thickness of 10 mm as defined in JIS-A-1405 is prepared from each of the sound absorbing materials of Example 1 and Comparative Example 1, and sound absorption at each frequency is performed in accordance with a normal incidence sound absorption coefficient measuring method by an in-tube method. The rate was measured. Table 1 shows the measurement results.
[0018]
[Table 1]

[0019]
(Test 2)
As Example 2, a sound-absorbing material was produced using rayon fibers having different fiber diameters from 11.5 μm to 27.1 μm, each being felted with a needle punch and adjusted to a bulk density of 50 kg / m ³ . Further, as Comparative Example 2, a glass long fiber having an average fiber diameter of 24 μm (trade name of Owens Corning Japan; Advantex) was similarly adjusted to a bulk density of 100 kg / m ³ with a needle punch. A sound absorbing material was created. A disk-shaped test piece having a thickness of 10 mm as defined in JIS-A-1405 is prepared from each of the sound absorbing materials of Example 2 and Comparative Example 2, and sound absorption at each frequency is performed in accordance with a normal incidence sound absorption coefficient measuring method by an in-tube method. The rate was measured. Table 2 shows the measurement results (the measurement results of Comparative Example 1 are also shown).
[0020]
[Table 2]

[0021]
(Test 3)
Next, a water permeability test was performed for each of the sound absorbing materials of Example 1 and Comparative Example 1. The sample size was a disk having a diameter of 91.5 mm and a thickness of 10 mm. In this test, after immersion in water at room temperature in the air, the side of the disk was lifted at one place, drained for 2 minutes in the vertical direction, and the weight increased.
[0022]
[Table 3]

[0023]
(Test 4)
Similarly, as Example 3 and Comparative Example 3, the sound absorbing materials of Example 1 and Comparative Example 1 were subjected to a surface treatment with a water repellent, and a water permeability test was performed. As the water repellent, a silicone water repellent (trade name of Toray Dow Corning Silicone Co., Ltd .; SM8706) was impregnated and applied, dried after drawing. By adjusting the amount of impregnation, the weight after drying was measured, and the target bulk density was determined. The sample size was a disk having a diameter of 91.5 mm and a thickness of 10 mm. In this test, after immersion in water at room temperature in the air, the side of the disk was lifted at one place, drained for 2 minutes in the vertical direction, and the weight increased.
[0024]
[Table 4]

[0025]
As described above, according to the sound absorbing material of the embodiment, the following functions and effects can be obtained.
[1] As shown in the measurement results shown in Table 1, the sound absorbing material of Example 1 has substantially the same sound absorbing performance as the sound absorbing material of Comparative Example 1 using glass fibers, even though lightweight organic fibers are used. Have In particular, the sound absorption performance is excellent in a frequency range of 1000 Hz or less.
[2] As shown in the measurement results shown in Table 2, the sound-absorbing material of Example 2 is a sound-absorbing material of Comparative Example 2 using thick glass filaments, even though organic fibers having a thick fiber diameter are used. In contrast, the sound absorption performance is equivalent or better. In particular, the sound absorption performance is excellent in a frequency range of 1000 Hz or less.
[3] As shown in Table 3, the sound-absorbing material of Example 1 shows better water permeability than glass fiber.
[4] As shown in Table 4, the sound-absorbing material in which the fiber was surface-treated with the water repellent of Example 3 exhibited good water permeability.
[0026]
Next, as shown in FIG. 1 to FIG. 3, the exhaust pipe 1 (inner pipe) of the fuel cell of the fuel cell vehicle and the outer periphery of the portion through which many small holes 2 are passed, Each of the felt-like sound absorbing materials is wound into a long band 11 (for example, a band width of 20 to 100 mm and a band thickness of 1 to 10 mm) and wound around the outer periphery of the exhaust pipe 1 by a plurality of turns. The sound absorbing material 3 made of Thereafter, a silencer housing 4 (outer pipe) made of an aluminum-plated steel pipe having an outer diameter of φ89 × inner diameter of φ87 × total length of 298 mm is extrapolated, and a gap between the exhaust pipe 1 and the silencer housing 4 is welded. Completed the silencer. Each sound absorbing material is filled in the internal space of the silencer housing 4. A drain hole 15 is provided through at least a part of the silencer housing 4. This silencer was well drained in an environment where the exhaust gas was water vapor, and was able to maintain good sound absorption performance over a long period of time.
[0027]
Further, each of the felt-like sound absorbing materials of Examples 1 to 3 is formed on the plate-like element 12 as shown in FIG. 4B, or is formed on the rod-like element 13 as shown in FIG. 4C. The cylindrical sound-absorbing material 3 was formed by bonding such that at least some of the inter-element bonding surfaces are directed from the inner periphery toward the outer periphery. The sound absorbing material 3 was also filled into the inner space of the silencer housing 4 disposed in the exhaust pipe 1 of the fuel cell of the fuel cell vehicle, thereby completing the silencer. This silencer was further drained and was able to maintain good sound absorption performance over a long period of time.
[0028]
In addition, this invention is not limited to the said embodiment, In the range which does not deviate from the meaning of invention, it can change suitably and can be actualized.
[0029]
【The invention's effect】
As described above in detail, according to the silencer for a fuel cell according to the present invention, in an environment where the exhaust gas is water vapor, drainage is good, good sound absorption performance can be maintained over a long period of time, and it is lightweight. There is an excellent effect that recycling is also possible.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a muffler according to an embodiment of the present invention with a part broken away.
FIG. 2 is a cross-sectional view showing the muffler with a part broken away.
FIG. 3 is a perspective view of the silencer when a sound absorbing material is formed.
4A is an enlarged view showing an organic fiber having a sound absorbing material crimp used in the silencer, FIG. 4B is a perspective view showing another example of the sound absorbing material, and FIG. 4C is another example of the sound absorbing material. It is a perspective view which shows an example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Exhaust pipe 2 Small hole 3 Sound absorption layer 4 Silencer housing 10 Organic fiber 11 Band 12 Element 13 Element 15 Drain hole

Claims

A silencer disposed in an exhaust pipe from a low-temperature fuel cell whose exhaust gas is water vapor and a reaction temperature is 300 ° C. or less, and a silencer housing provided with a drain hole, and an interior of the silencer housing And a sound-absorbing material adjusted to a bulk density of 20 to 200 kg / m ³ using organic fibers mainly having a crimp filled in at least a part of the space, and improving the drainage of the sound-absorbing material by adjusting the bulk density In addition, a silencer for a fuel cell, wherein water that has permeated the inside of the sound absorbing material is drained from the drain hole to the outside of the silencer .

A silencer disposed in an exhaust pipe from a low-temperature fuel cell whose exhaust gas is water vapor and a reaction temperature is 300 ° C. or less, and a silencer housing provided with a drain hole, and an interior of the silencer housing A sound absorbing material adjusted to a bulk density of 20 to 200 kg / m ³ using organic fibers mainly filled with water repellent treatment and filled in at least a part of the space, and the adjustment of the bulk density and the water repellent treatment; The noise absorber for a fuel cell improves drainage of the sound absorbing material and drains water that has permeated through the sound absorbing material from the drain hole to the outside of the silencer .

A silencer disposed in an exhaust pipe from a low-temperature fuel cell whose exhaust gas is water vapor and a reaction temperature is 300 ° C. or less, and a silencer housing provided with a drain hole, and an interior of the silencer housing Bulk density of 20 to 200 kg / m ³ using organic fibers filled in at least a part of the space and mainly having crimps and water-repellent treatment. The sound absorbing material is adjusted to the above, and the drainage of the sound absorbing material is improved by adjusting the bulk density and the water repellent treatment, and water that has permeated the inside of the sound absorbing material is removed from the drain hole to the outside of the silencer. Silencer for fuel cell that drains .

A silencer disposed in an exhaust pipe from a low-temperature fuel cell whose exhaust gas is water vapor and a reaction temperature is 300 ° C. or less, and a silencer housing provided with a drain hole, and an interior of the silencer housing Joining plate-like, rod-like or block-like elements mainly filled with felt made of organic fibers filled in at least a part of the space so that at least a part of the joint surface between the elements is directed from the inner periphery toward the outer periphery. The sound absorbing material is formed into a cylindrical shape and adjusted to a bulk density of 20 to 200 kg / m ³ , and the sound absorbing material is improved in drainage by the adjustment of the bulk density and the joint surface between the elements. A silencer for a fuel cell, wherein water that has permeated the inside of the material is drained from the drain hole to the outside of the silencer .

The silencer for a fuel cell according to any one of claims 1 to 4, wherein a drainage groove is provided on an inner surface of the silencer housing or an outer surface of the sound absorbing material.

The noise suppressor for a fuel cell according to any one of claims 1 to 4, wherein a spacer that also serves as a fixing support for the sound absorbing material is inserted between the silencer housing and the sound absorbing material, and an appropriate air layer is provided. vessel.

The organic fibers include polypropylene, polyethylene, polyethylene terephthalate, rayon, vinylon, nylon, polyester, polyvinyl chloride, acrylic, vinylidene and acetate synthetic fibers, and natural fibers of hemp, cotton, palm, bamboo, wool and silk. The silencer for a fuel cell according to any one of claims 1 to 6, which is a fiber composed of at least one selected.

The silencer for a fuel cell according to any one of claims 1 to 7 , wherein the organic fiber is a fiber having an average fiber diameter of 3 to 27 µm.