JP4147939B2

JP4147939B2 - Vehicle with fuel cell

Info

Publication number: JP4147939B2
Application number: JP2002377271A
Authority: JP
Inventors: 秀剛東
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 2002-12-26
Filing date: 2002-12-26
Publication date: 2008-09-10
Anticipated expiration: 2022-12-26
Also published as: JP2004207141A

Description

【０００１】
【発明の属する技術分野】
本発明は、燃料電池を搭載した燃料電池搭載車両に関するものである。
【０００２】
【従来の技術】
従来から固体高分子型燃料電池を加湿するため、その冷却層に供給する冷却水の一部を加湿水透過板および燃料極集電板に浸透させて高分子膜の加湿を行う直接水供給加湿法が提案されている（特許文献１参照）。
【０００３】
これは、燃料極と酸化剤極とで高分子電解質膜を挾持した単位セル毎に冷却板を挿入し、冷却板に供給された冷却水の一部を多孔質体の加湿水透過板および多孔質体の燃料極集電板を介して高分子電解質膜に供給して加湿するよう構成している。加えて、発電中に生じる熱を除去するためのポンプにより循環される冷却水の循環速度と電解質膜を加湿するための冷却水系の冷却水圧力を独立して制御できるように構成している。
【０００４】
【特許文献１】
特開平９−９２３１０号公報
【０００５】
【発明が解決しようとする課題】
ところで、燃料電池を車両に搭載する場合、走行中の車両の挙動により発生する前後方向およびまたは左右方向の加速度が燃料電池にも作用することから、燃料電池の内部に存在する冷却水流路内や加湿水透過板内の水も上記加速度に応じて偏りを生じる。この偏りが電解質膜から水を遠ざける方向に生じる場合には電解質膜への加湿が不足気味となり、逆に前記偏りが電解質膜へ水を近づける方向に生じる場合には電解質膜への加湿が過度となり、いずれの場合においても、発電性能の維持のために電解質膜の加湿を過不足なく行う必要がある。
【０００６】
しかしながら、上記従来例では、発電中に生じる熱を除去するためのポンプにより循環される冷却水の循環速度と電解質膜を加湿するための冷却水系の冷却水圧力を独立して制御できるように構成するのみで、車両搭載時における加速度による水の挙動を考慮するものではなく、車両搭載時に十分に発電性能を発揮できない可能性があった。
【０００７】
そこで本発明は、上記問題点に鑑みてなされたもので、高分子電解質膜への加湿に好適な燃料電池搭載車両を提供することを目的とする。
【０００８】
【課題を解決するための手段】
本発明は、多孔質体の加湿水透過板および燃料極集電板を介して冷却板に供給された冷却水の一部を高分子電解質膜に供給し、その高分子電解質膜を加湿するよう構成した燃料電池スタックを、燃料極を高分子電解質膜に対して車両前方に位置させて、そのセル積層方向が車両の前後方向となるよう車両に搭載した。
【０００９】
【発明の効果】
したがって、本発明では、多孔質体の加湿水透過板および燃料極集電板を介して冷却板に供給された冷却水の一部を高分子電解質膜に供給して高分子電解質膜を加湿するよう構成した燃料電池スタックを、燃料極を高分子電解質膜に対して車両前方に位置させて、そのセル積層方向が車両の前後方向となるよう車両に搭載した。このため、加湿水透過板内の水への慣性の方向が車両の加減速とそれに伴う発電要求に応じて、燃料ガスと冷却水との差圧が一定であっても、高分子電解質膜への加湿を自動調整することができる。
【００１０】
【発明の実施の形態】
以下、本発明の燃料電池搭載車両を各実施形態に基づいて説明する。
【００１１】
（第１実施形態）
図１〜図５は、本発明を適用した燃料電池搭載車両の第１実施形態を示し、図１は搭載する燃料電池スタックの部分断面図、図２は搭載する燃料電池システムの概略構成図、図３は燃料電池スタックの車両搭載状態を示す概略平面図、図４は燃料電池搭載車両の制御フローチャート、図５は動作を示すタイムチャートである。
【００１２】
図１において、燃料電池スタック１の単位セル２は、高分子電解質膜３の両側面に燃料極４および酸化剤極５を、高分子電解質膜３を挾持するよう配設し、酸化剤極４の背面には酸化剤極集電板６を、また、燃料極５の背面には多孔質体からなる燃料極集電板７を夫々配設して備える。そして、燃料極集電板７のさらに背面側に多孔質体からなる加湿水透過板８を介して冷却水流路９を備える冷却板１０を配設し、これらを複数組積層することにより燃料電池スタック１を構成している。
【００１３】
図２において、前記燃料電池スタック１は、燃料極５に燃料を供給する燃料ガス供給系１１と、酸化剤極４に酸化剤ガスを供給する酸化剤ガス供給系１２と、上記冷却板１０内にポンプ１６により冷却水を循環させ、発電中に生じる熱を除去する冷却水系１３と、その他制御系とにより固体高分子型燃料電池システムを構成する。
【００１４】
前記燃料極５には図示しない燃料源から供給された燃料が燃料処理装置１１Ａで水素に富んだ燃料ガスに改質されて供給され、前記酸化剤極４には酸化剤ガス供給系１２を介して酸化剤ガスが供給される。
【００１５】
前記冷却水系１３は、冷却水１４が貯められた冷却水タンク１５、ポンプ１６、背圧制御弁１７、熱交換器１８を冷却板１０の冷却水流路９と直列に接続して構成しており、冷却板１０に冷却水タンク１５に貯められた冷却水１４をポンプ１６によって供給し、供給された冷却水の一部を加湿水透過板８および燃料極集電板７に浸透させて燃料極５に供給して高分子電解質膜３を加湿するとともに、燃料ガスおよび酸化剤ガス中に蒸発させる。その際の蒸発潜熱は電池反応熱の一部を取り除く。残りの冷却水は、顕熱により残りの電池反応熱の取り除いた後、背圧制御弁１７、熱交換器１８を経て冷却水タンク１５に戻される。
【００１６】
前記冷却板１０から冷却水を熱交換器１８側に導く冷却水戻り配管に設けた背圧制御弁１７は、車両に配置した加速度検出手段２０より入力される加速度信号に応じてコントローラ２１により演算された開度に制御される。背圧制御弁１７の開度は背圧制御弁１７の上流側すなわち冷却板１０の冷却水流路９内の冷却水の圧力を調整する。冷却水の圧力を調整することにより燃料ガスとの差圧を変化させ、加湿水として燃料極５側に供給する水の量を調整することができる。即ち、背圧制御弁１７の開度を変えて冷却水の圧力を上昇させる（即ち、差圧を低下させる）と加湿水として供給する水の量を増加させ、背圧制御弁１７の開度を変えて冷却水の圧力を低下させる（即ち、差圧を増加させる）と加湿水として供給する水の量を減少させる。
【００１７】
本実施形態において、燃料電池スタック１は、図３に示すように、その積層方向Ａが車両前後方向となるよう車両２５に搭載する。図中の矢印Ｂは車両２５の進行方向を示し、２６は前輪、２７は後輪、２８はステアリングハンドルを模式的に示している。燃料電池スタック１に示す矢印Ａは燃料電池の単位セル２の燃料極５から電解質膜３への方向を示し、冷却水の電解質膜３への加湿水が冷却板１０から浸透する方向である。
【００１８】
前記加速度検出手段２０は、車両２５の前後方向の加速度を検出するよう配置する。加速度検出手段２０としては、所定の方向の加速度を検知する加速度計により加速度そのものを検知したり、ＡＢＳ（アンチロックブレーキシステム、以下ＡＢＳという）などに使用される車輪速センサを用いて単一センサから前後方向加速度を計算したり、左右輪２６の速度差から旋回方向を検知しつつ、外輪の速度から加速度の方向と大きさを計算するものであってもよい。
【００１９】
前記コントローラ２１は、加速度検出手段２０の出力から、車両２５が進行方向に所定値以上加速されていると判断される場合に背圧制御弁１７の開度を減少させ、車両２５が所定値以上減速されていると判断される場合に背圧制御弁１７の開度を増加させるよう制御する。このため、車両２５の前方への所定以上の加速時には冷却水の圧力を上昇させ加湿水として燃料極５側に供給する水の量を増加させ、車両の所定以上の減速時には冷却水の圧力を低下させ加湿水として燃料極５側に供給する水の量を減少させる。
【００２０】
以上の構成の燃料電池搭載車両の動作について以下に説明する。図４のフローチャートは差圧制御弁１７の開度を制御する制御ルーチンを示しており、コントローラ２１において一定周期毎に実行される。以下、図４に基づいて動作を説明する。
【００２１】
先ず、ステップＳ１では、加速度検知手段２０からの加速度信号を読み込み、ステップＳ２へ進む。
【００２２】
ステップＳ２では、ステップＳ１で読込んだ加速度信号の加速度方向、即ち、加速中か減速中かが判定され、加速中であればステップＳ３へ進み、減速中であればステップＳ５へ進む。
【００２３】
ステップＳ３では、読込んだ加速度信号により、加速度の大きさが予め設定した設定加速度より大きいか否かが判断され、加速度値が設定加速度より大きい場合にはステップＳ４へ進み、設定加速度より小さい場合には今回の処理を終了する。
【００２４】
前記ステップＳ３の加速度値が設定加速度より大きい場合には、冷却水流路９に供給された冷却水の一部の加湿水透過板８および燃料極集電板７への浸透が、冷却水が慣性により冷却水流路９側に留まるように作用するため、浸透し難くなり、結果として高分子膜３への加湿に必要な水が到達できなくなる状態である。しかも、車両２５の加速時には燃料電池スタック１からの電力により、図示しないモータを駆動するためにも、燃料電池で発生する電力をより多く要求され、燃料極５から水素イオン(プロトン)を酸化剤極４側に高分子膜３内を移動させて発電反応を促進させるためにも水が必要となる。
【００２５】
ステップＳ４では、背圧制御弁１７に対して所定時間だけ開度を減少させる指令を出力して今回の処理を終了する。前記所定時間は、コントローラ２１により実行される処理の周期を考慮して設定し、次回の処理時には指令が初期状態に復帰されているようにする。背圧制御弁１７の開度の減少は、冷却板１０の冷却水流路９中の冷却水の圧力を上昇させ、加湿水として燃料極５側に供給する水の量を増加させる。このため、水への慣性により燃料極５方向から高分子膜３への加湿が不十分となることが抑制され、加速時に消費される電力を補って発電させることができる。前記背圧制御弁１７の開度の減少量は、予め設定した開度量とすることもできるが、加速度値に応じて減少させる開度を変化させるようにしてもよい。
【００２６】
一方、ステップＳ５では、読込んだ加速度信号により、加速度（この場合には、減速度）の大きさが予め設定した設定加速度（設定減速度）より大きいか否かが判断され、加速度値が設定加速度より大きい場合にはステップＳ６へ進み、設定加速度より小さい場合には今回の処理を終了する。
【００２７】
前記ステップＳ５の加速度値が設定加速度より大きい場合には、冷却水流路９に供給された冷却水の一部の加湿水透過板８および燃料極集電板７への浸透が、冷却水が慣性により車両進行方向、即ち、冷却水流路９から高分子膜３側に浸透させる方向に作用するため、浸透し易くなり、結果として高分子膜３への加湿がより促進される状態となる。減速時には燃料電池に対して発電要求が低くなる傾向であるので、高分子膜３の表面で発電反応に使われない水が停滞しやすくなる。高分子膜３表面に水が停滞すると燃料ガスが高分子膜３へ到達し難くなるため発電反応が不安定になる。
【００２８】
ステップＳ６では、背圧制御弁１７に対して所定時間だけ開度を増加させる指令を出力して今回の処理を終了する。前記所定時間はステップＳ４と同様にコントローラにより実行される処理の周期を考慮して設定し、次回の処理時には指令が初期状態に復帰されているようにする。背圧制御弁１７の開度の増加は、冷却板１０の冷却水流路９中の冷却水の圧力を低下させ、加湿水として燃料極５側に供給する水の量を減少させる。このため、水への慣性により燃料極５方向から高分子膜３への加湿が過度となることを抑制し、減速時に生じる発電反応が不安定となることを防止できる。前記背圧制御弁１７の開度の増加量は、予め設定した開度量とすることもできるが、加速度値に応じて増加させる開度を変化させるようにしてもよい。
【００２９】
図５は、加速度の絶対値を縦軸とし時間を横軸として、加速度検知手段２０の作動を示すタイムチャートであり、加速度検知手段２０としてのセンサ出力値（太い実線）は加速度の真値（細い実線）に対して時間遅れがある。このため、制御動作開始の目標値に加速度の真値が達する三角印の制御動作開始時点ｔ１に対して、センサ出力値が制御動作開始の目標値に達する丸印の制御動作開始時点ｔ２が、基本的に真値から遅れる傾向で制御が動作される。この傾向は、所定の方向の加速度を検知する加速度計により加速度そのものを検知したり、ＡＢＳなどに使用される車輪速センサを用いて単一センサから前後方向加速度を計算したり、左右輪の速度差から旋回方向を検知しつつ、外輪の速度から加速度の方向と大きさを計算する場合等において生じる。しかし、所定の値を超えた場合に背圧制御弁１７を作動させて差圧制御を開始するような場合には、加速度の発生に応じた制御が行える。
【００３０】
以上のように、本実施形態の燃料電池搭載車両においては、冷却水と燃料ガスとの差圧を、加速時には（冷却水圧力を増加させて）減らすことで加湿水として燃料極５側に必要な水の量を増加させることができる。また、減速時には差圧を（冷却水圧力を減少させて）増加させることで必要以上に加湿水が燃料極５側に浸透して高分子膜３の表面が水で覆われやすくなり高分子膜３へのガス供給が不安定になって発生する発電の不安定になることを防ぐことができる。
【００３１】
なお、上記実施形態において、燃料電池スタック１の車両への搭載状態として、燃料極５から電解質膜３への方向が車両前方となる燃料電池スタック１について説明しているが、図示しないが、燃料極から電解質膜への方向が車両後方となる、即ち、燃料極を高分子電解質膜に対して車両前方となる燃料電池スタックとしてもよい。この場合には、冷却水圧力が一定、即ち、燃料ガスと冷却水との差圧が一定であっても、車両加速時には冷却水が慣性によって冷却板から電解質膜側に加湿水として供給され、車両減速時には冷却水が慣性によって冷却板内に留めるよう作用する。したがって、高分子電解質膜への加湿を自動調整することができ、冷却水圧力を背圧制御弁で制御する必要がなくなる。さらに必要であれば、車両加速時に冷却水圧力が低くなるよう背圧制御弁の開度を増加させ、車両減速時に冷却水圧力が高くなるよう背圧制御弁の開度を減少させるようにすればよい。
【００３２】
本実施形態においては、以下に記載する効果を奏することができる。
【００３３】
（ア）多孔質体の加湿水透過板８および燃料極集電板７を介して冷却板１０に供給された冷却水の一部を高分子電解質膜３に供給して高分子電解質膜３を加湿するよう構成した燃料電池スタック１を、燃料極５を高分子電解質膜３に対して車両前方に位置させて、そのセル積層方向が車両の前後方向となるよう車両に搭載した。このため、加湿水透過板８内の水への慣性の方向が車両の加減速とそれに伴う発電要求に応じて、燃料ガスと冷却水との差圧が一定であっても、高分子電解質膜３への加湿を自動調整することができる。
【００３４】
（イ）燃料電池スタック１をセル積層方向が車両の前後方向となるよう車両に搭載し、車両に車両前後方向の加速度を検知する手段２０を設け、燃料極集電板７を流通する燃料ガスと冷却板１０に流通する冷却水との差圧を前記加速度検知手段２０で検知する加速度方向に応じて制御したので、加湿水透過板８内の水への慣性により電解質膜３への加湿水に過不足が生じる場合に補正することができる。
【００３５】
（ウ）加速度検知手段２０により車両加速を検出した時には、冷却水圧力を上昇させて燃料極集電板７に流通する燃料ガスと冷却板１０に流通する冷却水との差圧を減少させるため、加速時の燃料電池が発電のための化学反応により燃料極５側の水分が不足することによる性能低下を防ぐことができる。
【００３６】
（エ）加速度検知手段２０により車両減速を検出した時には、冷却水圧力を低下させて燃料極集電板７に流通する燃料ガスと冷却板１０に流通する冷却水との差圧を増加させるため、減速時の特に燃料電池への発電要求が高くない時に必要量以上に加湿することで電解質膜３の表面が水で覆われることでおこる電解質膜３へのガス供給効率の低下とそれに伴う発電の不安定化を防ぐことができる。
【００３７】
（オ）加速度検知手段２０を加速度センサにより構成すると、車両への加速度と方向を正確に検知することで制御開始時期の最適化を図ることができる。
【００３８】
（カ）加速度検知手段２０を車輪速度センサから加速度を推定するよう構成すると、ＡＢＳ制御に使用される既存のセンサを流用することができる。
【００３９】
（第２実施形態）
図６は、本発明を適用した燃料電池搭載車両の第２実施形態を示す燃料電池スタックの車両搭載状態の概略平面図である。本実施形態においては、燃料電池スタックをその積層方向が車両左右方向となるように搭載したものである。なお、第１実施形態と同一部分には同一符号を付してその説明を省略ないし簡略化する。
【００４０】
図６に示すように、燃料電池スタック１は、その積層方向Ａが車両左右方向となるよう車両２５に搭載する。図中の矢印Ｂは車両２５の進行方向を示し、２６は前輪、２７は後輪、２８はステアリングハンドルを模式的に示している。燃料電池スタック１に示す矢印Ａは燃料電池の単位セル２の燃料極５から電解質膜３への方向を示し、冷却水の電解質膜３への加湿水が冷却板１０から浸透する方向である。
【００４１】
加速度検出手段２０は、車両２５の左右方向の加速度を検出するよう配置する。加速度検出手段２０としては、左右方向の加速度を検知する加速度計により加速度そのものを検知したり、ＡＢＳなどに使用される車輪速センサを用いて左右輪の速度差から旋回方向を検知しつつ、外輪の速度から加速度の方向と大きさを計算するものであってもよい。
【００４２】
前記コントローラ２１は、加速度検出手段２０の出力から、車両２５が進行方向の右方向に所定値以上加速されている（右方向への横加速度）と判断される場合に背圧制御弁１７の開度を減少させ、車両２５が進行方向左方向に所定値以上加速されている（左方向への横加速度）と判断される場合に背圧制御弁１７の開度を増加させるよう制御する。このため、車両２５の右方向への所定以上の加速時には冷却水の圧力を上昇させ加湿水として燃料極５側に供給する水の量を増加させ、車両の左方向への所定以上の加速時には冷却水の圧力を低下させ加湿水として燃料極５側に供給する水の量を減少させる。
【００４３】
コントローラ２１の具体的制御フローチャートは、図４に示す制御フローチャートと同様であり、ステップＳ２では、括弧内に記載したように、車両２５の旋回方向が右方向であるか左方向であるかが判断され、右旋回である場合にはステップＳ３へ進み、左旋回である場合にはステップＳ５へ進む。
【００４４】
以下、ステップＳ３、５で加速度の大きさが判断され、予め設定した設定加速度を超えている場合には、夫々ステップＳ４、６へ進み、背圧制御弁１７に対して所定時間だけ開度を増加または減少させる指令を出力して今回の処理を終了する。
【００４５】
したがって、冷却水と燃料ガスとの差圧を、右旋回時には（冷却水圧力を増加させて）減らすことで加湿水として燃料極５側に必要な水の量を増加させることができる。また、左旋回時には差圧を（冷却水圧力を減少させて）増加させることで必要以上に加湿水が燃料極５側に浸透して高分子膜３の表面が水で覆われやすくなり高分子膜３へのガス供給が不安定になって発生する発電の不安定になることを防ぐことができる。
【００４６】
ただし、制御を開始する際に、必ずしも加速度の発生と発電要求が一致しないため、発電量の傾向も併せて制御開始の判断要素とすることで、より木目細かい制御が実施できる。例えば、発電量が増加傾向である場合は、高分子膜３への加湿水を増量させるように冷却水の圧力を増加させて、ガスと冷却水の差圧を減らし、減少傾向である場合は加湿水を抑制するように冷却水の圧力を減少させて、ガスと冷却水の差圧を増やすようにする。
【００４７】
本実施形態においても、加速度検知手段２０としてのセンサ出力値は加速度の真値に対して時間遅れがあり、第１実施形態と同様、所定の値を超えた場合に背圧制御弁１７を作動させて差圧制御を開始するような場合には、加速度の発生に応じた制御が行える。
【００４８】
なお、上記実施形態において、燃料電池スタック１の車両への搭載状態として、燃料極５から電解質膜３への方向が車両右側となる燃料電池スタック１について説明しているが、図示しないが、燃料極５から電解質膜３への方向が車両左側となる燃料電池スタック１としてもよく、この場合には、車両右旋回時に冷却水圧力が低くなるよう背圧制御弁１７の開度を増加させ、車両左旋回時に冷却水圧力が高くなるよう背圧制御弁１７の開度を減少させるようにする。
【００４９】
本実施形態においては、第１実施形態における効果（ア）〜（カ）に加えて以下に記載した効果を奏することができる。
【００５０】
（キ）燃料電池スタック１をセル積層方向が車両の前後方向と直交するよう車両に搭載し、車両に車両左右方向の加速度を検知する手段２０を設け、燃料極集電板７に流通する燃料ガスと冷却板１０に流通する冷却水との差圧を加速度検知手段２０で検知する車両旋回方向、左右方向加速度および発電傾向に応じて制御するため、旋回時加速度による加湿水透過板８内の水への慣性で発生する電解質膜３への加湿水の過不足を補正することができる。
【００５１】
（第３実施形態）
図７および図８は、本発明を適用した燃料電池搭載車両の第３実施形態を示し、図７は燃料電池搭載車両の制御フローチャート、図５は動作を示すタイムチャートである。本実施形態においては、加速度検知手段による加速度に基づいて制御することに代えて加速度予測手段による加速度に基づいて制御するようにしたものである。なお、第１実施形態および第２実施形態と同一装置には同一符号を付してその説明を省略ないし簡略化する。
【００５２】
図７において、ステップＳ２〜ステップＳ６は、第１実施形態または第２実施形態の制御フローチャートを示す図４のステップＳ２〜ステップＳ６と同様のものであり、ステップＳ１１およびステップＳ１１に加速度情報を入力する加速度検知手段としての加速度予測手段２０Ａを新規な構成としている。
【００５３】
加速度予測手段２０ＡおよびステップＳ１１の第１実施例は、加速度予測手段２０Ａを、車両への加速度を発生するようなアクセル、ブレーキ、または、ステアリングハンドル２８の操作の変化速度を検知し、その時の車速を考慮することで、運動保存則から発生が予想される加速度を予測するものである。
【００５４】
例えば、ドライバーのブレーキペダルまたはアクセルペダルの踏み込み状態、例えば、踏み込み量や踏み込み時間、さらには、車両前方の障害物や車両との距離を検出し、これらの検出結果に基づき、あるいは、組み合わせた結果に基づき、ドライバーが欲求する車両姿勢変化とそれにともなう加速度を推定する。
【００５５】
推定された加速度は、ステップＳ１１に読込まれ、ステップＳ２〜ステップＳ６による背圧制御弁１７の制御の基礎データとして利用される。
【００５６】
図８は、加速度の絶対値を縦軸とし時間を横軸として加速度を示すタイムチャートであり、加速度予測手段２０Ａとしてのセンサ出力値（図中の下の線）は加速度の真値（図中の上の線）に対して先行する。即ち、制御動作開始の目標値に加速度の真値が達する三角印の制御動作開始時点ｔ３に対して、加速度予測手段２０Ａのセンサ出力値が制御動作開始の目標値に達する丸印の制御動作開始時点ｔ４が、基本的に真値より先行する傾向で制御が動作される。したがって、加速度の真値より早い傾向で制御動作が可能となる。
【００５７】
以上の加速度予測手段２０Ａを用いる第１実施例では、車両の加速度に対して背圧制御弁１７（圧力制御系）の応答が遅い場合に、先読み制御を行い必要な応答を達成することができ、背圧制御弁１７による差圧制御を遅れなく実施できる。
【００５８】
加速度予測手段２０ＡおよびステップＳ１１の第２実施例は、加速度予測手段２０Ａを、車両２５のナビゲーションシステム等の有線や無線から得られる目的地までの道路勾配や道路の曲率半径等の道路状況、ドライバーの運転能力やドライバーの癖等から、将来起こりうる車両姿勢変化にともなう加速度を事前に推定するものである。推定された加速度は、ステップＳ１１に読込まれ、ステップＳ２〜ステップＳ６による背圧制御弁１７の制御の基礎データとして利用される。
【００５９】
以上の加速度予測手段２０Ａを用いる第２実施例では、先読み制御を行い必要な応答を達成することができ、背圧制御弁１７による差圧制御の制御の精度を高めることができる。
【００６０】
また、車両のナビゲーションシステム等の有線や無線から得られる道路の勾配または曲率半径、およびその長さと進入速度から車両の最大加速度を事前に推定する機能を加速度予測手段２０Ａに追加するものであってもよい。この推定した最大加速度に応じて背圧制御弁１７による差圧制御の差圧目標値を決定するようにすると、背圧制御の最適化を図ることができる。
【００６１】
本実施形態においては、第１実施形態における効果（ア）〜（カ）および第２実施形態における効果（キ）に加えて、以下に記載する効果を奏することができる。
【００６２】
（ク）車速と運転手の運転動作から加速度を推定する加速度検知手段としての加速度予測手段２０Ａを備えるため、運転手の運転動作から推測される加速度発生を予測することができ、予備制御を行い制御の最適化を図ることができる。
【００６３】
（ケ）進行方向の進路障害物との距離を測定する手段による進路障害物との距離に応じて燃料極集電板７に流通する燃料ガスと冷却板１０に流通する冷却水との差圧を制御するため、車両の走行前方環境を推定し運転者の停止欲求または加速欲求を推測して予備制御することができる。
【００６４】
（コ）進行方向の進路障害物との距離を測定する手段による進路障害物との距離と車両のブレーキペダルまたはアクセルペダルの操作変化とに連動して燃料極集電板７に流通する燃料ガスと冷却板１０に流通する冷却水との差圧を制御するため、より細かく検知してより木目細かい制御が実施できる。
【００６５】
（サ）車両外部から有線または無線にて得られる道路勾配または曲率等の車両走行環境から車両の姿勢変化を推定する手段よりの推定値に基づいて燃料極集電板７に流通する燃料ガスと冷却板に流通する冷却水との差圧を予備制御するため、将来走行が予想される路上での車両走行姿勢を予測することができ、予備制御を行い、制御の最適化を図ることができる。
【００６６】
（シ）車両姿勢変化推定手段２０Ａよりの道路の勾配又は曲率とその距離と進入車速から推測される車両加速度のピークに比例して前記制御の目標値の最大値を設定するため、制御の最適化を図ることができる。
【図面の簡単な説明】
【図１】本発明の一実施形態を示す燃料電池搭載車両における燃料電池スタックの部分断面図。
【図２】同じく搭載する燃料電池システムの概略構成図。
【図３】燃料電池スタックの車両搭載状態を示す概略平面図。
【図４】燃料電池搭載車両の制御フローチャート。
【図５】燃料電池搭載車両の動作を示すタイムチャート。
【図６】本発明の第２実施形態を示す燃料電池搭載車両の概略平面図。
【図７】本発明の第３実施形態を示す燃料電池搭載車両の制御フローチャート。
【図８】燃料電池搭載車両の動作を示すタイムチャート。
【符号の説明】
１燃料電池スタック
２単位セル
３高分子電解質膜
４酸化剤極
５燃料極
６酸化剤極集電板
７燃料極集電板
８加湿水透過板
９冷却水流路
１０冷却板
１３冷却水系
１５冷却水タンク
１６ポンプ
１７背圧制御弁
２０加速度検知手段
２１コントローラ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel cell vehicle equipped with a fuel cell.
[0002]
[Prior art]
Conventionally, in order to humidify a polymer electrolyte fuel cell, direct water supply humidification that humidifies the polymer membrane by infiltrating a portion of the cooling water supplied to the cooling layer into the humidified water permeation plate and the fuel electrode current collector plate A method has been proposed (see Patent Document 1).
[0003]
This is because a cooling plate is inserted into each unit cell holding the polymer electrolyte membrane between the fuel electrode and the oxidant electrode, and a part of the cooling water supplied to the cooling plate is passed through the humidified water permeating plate and the porous plate. The material is supplied to the polymer electrolyte membrane via a fuel electrode current collector plate and humidified. In addition, the cooling water circulating speed by the pump for removing heat generated during power generation and the cooling water pressure of the cooling water system for humidifying the electrolyte membrane can be controlled independently.
[0004]
[Patent Document 1]
JP-A-9-92310
[0005]
[Problems to be solved by the invention]
By the way, when a fuel cell is mounted on a vehicle, the longitudinal and / or lateral acceleration generated by the behavior of the traveling vehicle also acts on the fuel cell. The water in the humidified water transmission plate is also biased according to the acceleration. When this bias occurs in the direction of moving water away from the electrolyte membrane, humidification of the electrolyte membrane becomes insufficient. Conversely, when the bias occurs in a direction of bringing water closer to the electrolyte membrane, humidification of the electrolyte membrane becomes excessive. In any case, it is necessary to humidify the electrolyte membrane without excess or deficiency in order to maintain power generation performance.
[0006]
However, the conventional example is configured such that the circulation rate of the cooling water circulated by the pump for removing heat generated during power generation and the cooling water pressure of the cooling water system for humidifying the electrolyte membrane can be controlled independently. However, it does not consider the behavior of water due to acceleration when mounted on the vehicle, and there is a possibility that the power generation performance cannot be sufficiently exhibited when mounted on the vehicle.
[0007]
Accordingly, the present invention has been made in view of the above problems, and an object thereof is to provide a fuel cell-equipped vehicle suitable for humidifying a polymer electrolyte membrane.
[0008]
[Means for Solving the Problems]
According to the present invention, a part of cooling water supplied to a cooling plate via a humidified water permeation plate and a fuel electrode current collector plate of a porous body is supplied to the polymer electrolyte membrane, and the polymer electrolyte membrane is humidified. The configured fuel cell stack was mounted on the vehicle such that the fuel electrode was positioned in front of the polymer electrolyte membrane and the cell stacking direction was the front-rear direction of the vehicle.
[0009]
【The invention's effect】
Therefore, in the present invention, the polymer electrolyte membrane is humidified by supplying a part of the cooling water supplied to the cooling plate via the humidified water permeation plate of the porous body and the fuel electrode current collector plate to the polymer electrolyte membrane. The fuel cell stack configured as described above was mounted on the vehicle such that the fuel electrode was positioned in front of the polymer electrolyte membrane and the cell stacking direction was the front-rear direction of the vehicle. For this reason, even if the direction of inertia of water in the humidified water transmission plate is constant according to the acceleration / deceleration of the vehicle and the power generation demand accompanying it, even if the differential pressure between the fuel gas and the cooling water is constant, the polymer electrolyte membrane The humidification of can be adjusted automatically.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a fuel cell vehicle according to the present invention will be described based on each embodiment.
[0011]
(First embodiment)
1 to 5 show a first embodiment of a vehicle equipped with a fuel cell to which the present invention is applied, FIG. 1 is a partial sectional view of a fuel cell stack to be installed, and FIG. 2 is a schematic configuration diagram of a fuel cell system to be installed, FIG. 3 is a schematic plan view showing a vehicle-mounted state of the fuel cell stack, FIG. 4 is a control flowchart of the vehicle equipped with the fuel cell, and FIG. 5 is a time chart showing the operation.
[0012]
In FIG. 1, a unit cell 2 of a fuel cell stack 1 is provided with a fuel electrode 4 and an oxidant electrode 5 on both sides of a polymer electrolyte membrane 3 so as to hold the polymer electrolyte membrane 3, and an oxidant electrode 4 An oxidant electrode current collector plate 6 is disposed on the back surface of the fuel electrode 5, and a fuel electrode current collector plate 7 made of a porous material is disposed on the back surface of the fuel electrode 5. A cooling plate 10 having a cooling water flow path 9 is disposed on the back side of the fuel electrode current collector plate 7 via a humidified water transmission plate 8 made of a porous material, and a plurality of sets of these are laminated to form a fuel cell. Stack 1 is configured.
[0013]
In FIG. 2, the fuel cell stack 1 includes a fuel gas supply system 11 that supplies fuel to the fuel electrode 5, an oxidant gas supply system 12 that supplies oxidant gas to the oxidant electrode 4, and the inside of the cooling plate 10. A solid polymer fuel cell system is constituted by a cooling water system 13 that circulates cooling water by a pump 16 and removes heat generated during power generation, and another control system.
[0014]
Fuel supplied from a fuel source (not shown) is supplied to the fuel electrode 5 after being reformed into a fuel gas rich in hydrogen by a fuel processing device 11A, and supplied to the oxidant electrode 4 via an oxidant gas supply system 12. The oxidant gas is supplied.
[0015]
The cooling water system 13 is configured by connecting a cooling water tank 15 in which cooling water 14 is stored, a pump 16, a back pressure control valve 17, and a heat exchanger 18 in series with the cooling water flow path 9 of the cooling plate 10. Then, the cooling water 14 stored in the cooling water tank 15 is supplied to the cooling plate 10 by the pump 16, and a part of the supplied cooling water is permeated into the humidified water transmission plate 8 and the fuel electrode current collector plate 7 to form the fuel electrode. 5 to humidify the polymer electrolyte membrane 3 and evaporate it into the fuel gas and oxidant gas. The latent heat of vaporization at that time removes part of the battery reaction heat. The remaining cooling water is removed from the remaining battery reaction heat by sensible heat, and then returned to the cooling water tank 15 via the back pressure control valve 17 and the heat exchanger 18.
[0016]
A back pressure control valve 17 provided in a cooling water return pipe that guides cooling water from the cooling plate 10 to the heat exchanger 18 side is calculated by a controller 21 in accordance with an acceleration signal input from an acceleration detection means 20 disposed in the vehicle. The controlled opening is controlled. The opening degree of the back pressure control valve 17 adjusts the pressure of the cooling water upstream of the back pressure control valve 17, that is, in the cooling water flow path 9 of the cooling plate 10. By adjusting the pressure of the cooling water, the pressure difference with the fuel gas can be changed, and the amount of water supplied to the fuel electrode 5 side as humidified water can be adjusted. That is, when the opening of the back pressure control valve 17 is changed to increase the pressure of the cooling water (that is, to reduce the differential pressure), the amount of water supplied as humidified water is increased, and the opening of the back pressure control valve 17 is increased. When the pressure of the cooling water is decreased (that is, the differential pressure is increased) by changing, the amount of water supplied as humidified water is decreased.
[0017]
In the present embodiment, as shown in FIG. 3, the fuel cell stack 1 is mounted on the vehicle 25 such that the stacking direction A is the vehicle front-rear direction. An arrow B in the figure indicates the traveling direction of the vehicle 25, 26 is a front wheel, 27 is a rear wheel, and 28 is a steering handle. An arrow A shown in the fuel cell stack 1 indicates the direction from the fuel electrode 5 of the unit cell 2 of the fuel cell to the electrolyte membrane 3, and the humidified water to the electrolyte membrane 3 of the cooling water penetrates from the cooling plate 10.
[0018]
The acceleration detection means 20 is arranged to detect the acceleration in the front-rear direction of the vehicle 25. As the acceleration detecting means 20, the acceleration itself is detected by an accelerometer that detects acceleration in a predetermined direction, or a single sensor is used by using a wheel speed sensor used for ABS (anti-lock brake system, hereinafter referred to as ABS). The direction and magnitude of the acceleration may be calculated from the speed of the outer wheel while calculating the longitudinal acceleration from the speed, or detecting the turning direction from the speed difference between the left and right wheels 26.
[0019]
The controller 21 reduces the opening of the back pressure control valve 17 when the vehicle 25 is determined to be accelerated by a predetermined value or more in the traveling direction from the output of the acceleration detection means 20, and the vehicle 25 is equal to or higher than the predetermined value. When it is determined that the vehicle is decelerated, control is performed to increase the opening of the back pressure control valve 17. For this reason, the pressure of the cooling water is increased when the vehicle 25 is accelerated to the front of the vehicle 25 to increase the amount of water supplied to the fuel electrode 5 as humidified water, and the pressure of the cooling water is increased when the vehicle is decelerated more than the predetermined. The amount of water supplied to the fuel electrode 5 side as humidified water is reduced.
[0020]
The operation of the fuel cell vehicle having the above configuration will be described below. The flowchart of FIG. 4 shows a control routine for controlling the opening degree of the differential pressure control valve 17 and is executed by the controller 21 at regular intervals. The operation will be described below with reference to FIG.
[0021]
First, in step S1, an acceleration signal from the acceleration detecting means 20 is read, and the process proceeds to step S2.
[0022]
In step S2, the acceleration direction of the acceleration signal read in step S1, that is, whether the vehicle is accelerating or decelerating is determined. If it is accelerating, the process proceeds to step S3, and if it is decelerating, the process proceeds to step S5.
[0023]
In step S3, it is determined whether or not the magnitude of the acceleration is greater than a preset set acceleration based on the read acceleration signal. If the acceleration value is greater than the set acceleration, the process proceeds to step S4. This processing is terminated.
[0024]
When the acceleration value in the step S3 is larger than the set acceleration, a part of the cooling water supplied to the cooling water flow passage 9 permeates into the humidified water transmission plate 8 and the fuel electrode current collecting plate 7, and the cooling water is inertial. Therefore, it becomes difficult to permeate, and as a result, water necessary for humidification to the polymer film 3 cannot reach. Moreover, in order to drive a motor (not shown) by the electric power from the fuel cell stack 1 when the vehicle 25 is accelerated, more electric power generated in the fuel cell is required, and hydrogen ions (protons) are oxidized from the fuel electrode 5. Water is also required to move the inside of the polymer film 3 to the pole 4 side to promote the power generation reaction.
[0025]
In step S4, a command to decrease the opening degree for a predetermined time is output to the back pressure control valve 17, and the current process is terminated. The predetermined time is set in consideration of the cycle of processing executed by the controller 21 so that the command is restored to the initial state at the next processing. Decreasing the opening of the back pressure control valve 17 increases the pressure of the cooling water in the cooling water flow path 9 of the cooling plate 10 and increases the amount of water supplied to the fuel electrode 5 side as humidified water. For this reason, it is suppressed that the humidification from the direction of the fuel electrode 5 to the polymer film 3 is insufficient due to the inertia of water, and the power consumed during acceleration can be supplemented to generate power. The amount of decrease in the opening degree of the back pressure control valve 17 may be a preset opening amount, but the opening degree to be decreased may be changed according to the acceleration value.
[0026]
On the other hand, in step S5, it is determined from the read acceleration signal whether the magnitude of the acceleration (in this case, deceleration) is greater than a preset acceleration (set deceleration), and the acceleration value is set. If it is larger than the acceleration, the process proceeds to step S6. If it is smaller than the set acceleration, the current process is terminated.
[0027]
When the acceleration value in the step S5 is larger than the set acceleration, a part of the cooling water supplied to the cooling water flow passage 9 permeates into the humidified water transmission plate 8 and the fuel electrode current collector plate 7, and the cooling water is inertial. This acts in the vehicle traveling direction, that is, in the direction of permeation from the cooling water flow path 9 to the polymer film 3 side, so that permeation is facilitated, and as a result, humidification of the polymer film 3 is further promoted. At the time of deceleration, the power generation requirement for the fuel cell tends to be low, so that water that is not used for the power generation reaction tends to stagnate on the surface of the polymer membrane 3. When water is stagnated on the surface of the polymer membrane 3, the fuel gas is difficult to reach the polymer membrane 3, so that the power generation reaction becomes unstable.
[0028]
In step S6, a command for increasing the opening degree for a predetermined time is output to the back pressure control valve 17, and the current process is terminated. The predetermined time is set in consideration of the cycle of processing executed by the controller in the same manner as in step S4, and the command is restored to the initial state at the next processing. The increase in the opening degree of the back pressure control valve 17 decreases the pressure of the cooling water in the cooling water passage 9 of the cooling plate 10 and decreases the amount of water supplied to the fuel electrode 5 side as humidified water. For this reason, it is possible to suppress excessive humidification from the direction of the fuel electrode 5 to the polymer film 3 due to inertia of water, and to prevent the power generation reaction that occurs during deceleration from becoming unstable. The increase amount of the opening of the back pressure control valve 17 can be a preset opening amount, but the opening to be increased may be changed according to the acceleration value.
[0029]
FIG. 5 is a time chart showing the operation of the acceleration detection means 20 with the absolute value of acceleration on the vertical axis and time on the horizontal axis. The sensor output value (thick solid line) as the acceleration detection means 20 is the true value of acceleration ( There is a time delay with respect to the thin solid line. Therefore, with respect to the control operation start time t1 indicated by a triangle where the true value of acceleration reaches the target value for starting the control operation, the control operation start time t2 indicated by a circle where the sensor output value reaches the target value for starting the control operation is Control is basically operated with a tendency to lag behind the true value. This tendency is caused by detecting the acceleration itself with an accelerometer that detects acceleration in a predetermined direction, calculating the longitudinal acceleration from a single sensor using a wheel speed sensor used for ABS, etc. This occurs when the direction and magnitude of acceleration are calculated from the speed of the outer wheel while detecting the turning direction from the difference. However, when the differential pressure control is started by operating the back pressure control valve 17 when a predetermined value is exceeded, control according to the generation of acceleration can be performed.
[0030]
As described above, in the fuel cell vehicle according to the present embodiment, it is necessary on the fuel electrode 5 side as humidified water by reducing the differential pressure between the cooling water and the fuel gas during acceleration (by increasing the cooling water pressure). The amount of fresh water can be increased. Further, at the time of deceleration, the differential pressure is increased (by reducing the cooling water pressure), so that the humidified water permeates the fuel electrode 5 more than necessary, and the surface of the polymer film 3 is easily covered with water. 3 can be prevented from becoming unstable due to unstable gas supply to 3.
[0031]
In the above embodiment, the fuel cell stack 1 in which the direction from the fuel electrode 5 to the electrolyte membrane 3 is the front of the vehicle has been described as the fuel cell stack 1 mounted on the vehicle. The direction from the electrode to the electrolyte membrane may be the rear of the vehicle, that is, the fuel electrode may be a fuel cell stack that is the front of the vehicle with respect to the polymer electrolyte membrane. In this case, even if the cooling water pressure is constant, that is, the differential pressure between the fuel gas and the cooling water is constant, the cooling water is supplied as humidified water from the cooling plate to the electrolyte membrane side by inertia during vehicle acceleration, When the vehicle decelerates, the cooling water acts so as to remain in the cooling plate due to inertia. Therefore, the humidification of the polymer electrolyte membrane can be automatically adjusted, and it is not necessary to control the cooling water pressure with the back pressure control valve. Furthermore, if necessary, the opening of the back pressure control valve is increased so that the cooling water pressure is lowered during vehicle acceleration, and the opening of the back pressure control valve is decreased so that the cooling water pressure is increased during vehicle deceleration. That's fine.
[0032]
In the present embodiment, the following effects can be achieved.
[0033]
(A) A part of the cooling water supplied to the cooling plate 10 through the humidified water permeation plate 8 and the fuel electrode current collector plate 7 is supplied to the polymer electrolyte membrane 3 to thereby form the polymer electrolyte membrane 3. The fuel cell stack 1 configured to be humidified was mounted on the vehicle such that the fuel electrode 5 was positioned in front of the polymer electrolyte membrane 3 and the cell stacking direction was the front-rear direction of the vehicle. Therefore, even if the direction of inertia of water in the humidified water permeable plate 8 is constant depending on the acceleration / deceleration of the vehicle and the power generation requirement accompanying it, the polymer electrolyte membrane is constant. The humidification to 3 can be automatically adjusted.
[0034]
(A) The fuel cell stack 1 is mounted on the vehicle so that the cell stacking direction is the front-rear direction of the vehicle, the fuel gas flowing through the anode current collector plate 7 is provided on the vehicle, and means 20 for detecting acceleration in the front-rear direction Since the differential pressure between the cooling water flowing through the cooling plate 10 and the cooling water flowing through the cooling plate 10 is controlled in accordance with the acceleration direction detected by the acceleration detecting means 20, the humidifying water to the electrolyte membrane 3 is caused by the inertia of the water in the humidifying water transmitting plate 8. It can be corrected when excess or deficiency occurs.
[0035]
(C) When the acceleration detection means 20 detects vehicle acceleration, the coolant pressure is increased to reduce the differential pressure between the fuel gas flowing through the anode current collecting plate 7 and the cooling water flowing through the cooling plate 10. The fuel cell at the time of acceleration can prevent the performance deterioration due to the lack of moisture on the fuel electrode 5 side due to the chemical reaction for power generation.
[0036]
(D) When the acceleration detection means 20 detects vehicle deceleration, the cooling water pressure is decreased to increase the differential pressure between the fuel gas flowing through the anode current collecting plate 7 and the cooling water flowing through the cooling plate 10. Further, when the power generation requirement for the fuel cell is not high at the time of deceleration, the gas supply efficiency to the electrolyte membrane 3 is reduced due to the surface of the electrolyte membrane 3 being covered with water by humidifying more than necessary, and the power generation associated therewith Can be prevented from becoming unstable.
[0037]
(E) When the acceleration detection means 20 is configured by an acceleration sensor, the control start timing can be optimized by accurately detecting the acceleration and direction to the vehicle.
[0038]
(F) If the acceleration detection means 20 is configured to estimate the acceleration from the wheel speed sensor, an existing sensor used for ABS control can be used.
[0039]
(Second Embodiment)
FIG. 6 is a schematic plan view of a fuel cell stack mounted in a vehicle showing a second embodiment of a fuel cell mounted vehicle to which the present invention is applied. In the present embodiment, the fuel cell stack is mounted so that the stacking direction is the vehicle left-right direction. In addition, the same code | symbol is attached | subjected to the same part as 1st Embodiment, and the description is abbreviate | omitted or simplified.
[0040]
As shown in FIG. 6, the fuel cell stack 1 is mounted on the vehicle 25 such that the stacking direction A is the vehicle left-right direction. An arrow B in the figure indicates the traveling direction of the vehicle 25, 26 is a front wheel, 27 is a rear wheel, and 28 is a steering handle. An arrow A shown in the fuel cell stack 1 indicates the direction from the fuel electrode 5 of the unit cell 2 of the fuel cell to the electrolyte membrane 3, and the humidified water to the electrolyte membrane 3 of the cooling water penetrates from the cooling plate 10.
[0041]
The acceleration detection means 20 is arranged so as to detect the acceleration in the left-right direction of the vehicle 25. As the acceleration detecting means 20, the acceleration itself is detected by an accelerometer that detects the acceleration in the left and right direction, or the outer wheel is detected while detecting the turning direction from the speed difference between the left and right wheels using a wheel speed sensor used for ABS or the like. It is also possible to calculate the direction and magnitude of acceleration from the speed.
[0042]
The controller 21 opens the back pressure control valve 17 when it is determined from the output of the acceleration detection means 20 that the vehicle 25 is accelerated to the right in the traveling direction by a predetermined value or more (lateral acceleration in the right direction). When the vehicle 25 is determined to be accelerated to the left in the traveling direction by a predetermined value or more (lateral acceleration in the left direction), the opening degree of the back pressure control valve 17 is controlled to increase. For this reason, when the vehicle 25 is accelerated to the right or above in the right direction, the pressure of the cooling water is increased to increase the amount of water supplied to the fuel electrode 5 side as humidified water, and when the vehicle 25 is accelerated to the left or above the predetermined amount. The pressure of the cooling water is lowered to reduce the amount of water supplied to the fuel electrode 5 side as humidified water.
[0043]
The specific control flowchart of the controller 21 is the same as the control flowchart shown in FIG. 4. In step S2, it is determined whether the turning direction of the vehicle 25 is the right direction or the left direction as described in parentheses. If it is a right turn, the process proceeds to step S3. If it is a left turn, the process proceeds to step S5.
[0044]
Thereafter, the magnitude of the acceleration is determined in steps S3 and S5, and if the acceleration exceeds a preset acceleration, the process proceeds to steps S4 and S6, respectively, and the opening degree is set to the back pressure control valve 17 for a predetermined time. A command to increase or decrease is output and the current process is terminated.
[0045]
Therefore, the amount of water necessary for the fuel electrode 5 side as humidified water can be increased by reducing the differential pressure between the cooling water and the fuel gas when turning right (by increasing the cooling water pressure). Further, when turning counterclockwise, the differential pressure is increased (decreasing the cooling water pressure), so that the humidified water permeates the fuel electrode 5 more than necessary and the surface of the polymer film 3 is easily covered with water. It is possible to prevent the generation of power from becoming unstable due to unstable gas supply to the membrane 3.
[0046]
However, when the control is started, the generation of acceleration and the power generation request do not always coincide with each other. Therefore, the finer control can be performed by using the tendency of the power generation amount as a determination factor for the control start. For example, when the power generation amount is increasing, the pressure of the cooling water is increased so as to increase the amount of humidified water to the polymer film 3, and the differential pressure between the gas and the cooling water is decreased. The pressure of the cooling water is decreased so as to suppress the humidified water, and the differential pressure between the gas and the cooling water is increased.
[0047]
Also in the present embodiment, the sensor output value as the acceleration detecting means 20 has a time delay with respect to the true value of acceleration, and the back pressure control valve 17 is activated when it exceeds a predetermined value, as in the first embodiment. When differential pressure control is started, control according to the generation of acceleration can be performed.
[0048]
In the above-described embodiment, the fuel cell stack 1 in which the fuel cell stack 1 is mounted on the vehicle has been described with respect to the fuel cell stack 1 in which the direction from the fuel electrode 5 to the electrolyte membrane 3 is the right side of the vehicle. The fuel cell stack 1 may be configured such that the direction from the electrode 5 to the electrolyte membrane 3 is the left side of the vehicle. In this case, the opening degree of the back pressure control valve 17 is increased so that the cooling water pressure is lowered when the vehicle turns right. The opening of the back pressure control valve 17 is decreased so that the coolant pressure increases when the vehicle turns left.
[0049]
In the present embodiment, in addition to the effects (a) to (f) in the first embodiment, the following effects can be achieved.
[0050]
(G) The fuel cell stack 1 is mounted on the vehicle so that the cell stacking direction is orthogonal to the vehicle front-rear direction, and the vehicle is provided with means 20 for detecting acceleration in the vehicle left-right direction. In order to control the differential pressure between the gas and the cooling water flowing through the cooling plate 10 according to the vehicle turning direction, the left-right acceleration and the power generation tendency detected by the acceleration detecting means 20, It is possible to correct excess / deficiency of humidified water to the electrolyte membrane 3 generated by inertia with water.
[0051]
(Third embodiment)
7 and 8 show a third embodiment of a vehicle equipped with a fuel cell to which the present invention is applied, FIG. 7 is a control flowchart of the vehicle equipped with a fuel cell, and FIG. 5 is a time chart showing the operation. In the present embodiment, the control is based on the acceleration by the acceleration prediction means instead of the control based on the acceleration by the acceleration detection means. In addition, the same code | symbol is attached | subjected to the same apparatus as 1st Embodiment and 2nd Embodiment, and the description is abbreviate | omitted or simplified.
[0052]
In FIG. 7, steps S2 to S6 are the same as steps S2 to S6 of FIG. 4 showing the control flowchart of the first embodiment or the second embodiment, and acceleration information is input to steps S11 and S11. The acceleration predicting means 20A serving as the acceleration detecting means that has a new configuration is used.
[0053]
In the first embodiment of the acceleration predicting means 20A and step S11, the acceleration predicting means 20A detects the changing speed of the operation of the accelerator, the brake, or the steering handle 28 that generates acceleration to the vehicle, and the vehicle speed at that time is detected. By considering the above, the acceleration expected to be generated from the motion conservation law is predicted.
[0054]
For example, the driver's brake pedal or accelerator pedal depressing state, for example, the depressing amount and depressing time, as well as the distance to the obstacle or vehicle ahead of the vehicle, and the result of these detections or combination Based on the above, the vehicle posture change desired by the driver and the accompanying acceleration are estimated.
[0055]
The estimated acceleration is read in step S11 and used as basic data for controlling the back pressure control valve 17 in steps S2 to S6.
[0056]
FIG. 8 is a time chart showing acceleration with the absolute value of acceleration on the vertical axis and time on the horizontal axis, and the sensor output value (lower line in the figure) as the acceleration predicting means 20A is the true value of acceleration (in the figure). Preceding the line). That is, with respect to the control operation start time point t3 where the true value of acceleration reaches the target value for starting the control operation, the control operation start of the circle where the sensor output value of the acceleration predicting means 20A reaches the target value for starting the control operation is started. The control is operated in a tendency that the time point t4 basically precedes the true value. Therefore, the control operation can be performed with a tendency to be faster than the true value of the acceleration.
[0057]
In the first embodiment using the acceleration predicting means 20A described above, when the response of the back pressure control valve 17 (pressure control system) is slow with respect to the acceleration of the vehicle, it is possible to achieve the necessary response by performing the look-ahead control. The differential pressure control by the back pressure control valve 17 can be performed without delay.
[0058]
In the second embodiment of the acceleration prediction means 20A and step S11, the acceleration prediction means 20A is used as a road condition such as a road gradient to a destination obtained from wired or wireless such as a navigation system of the vehicle 25, a road curvature radius, a driver, etc. This is to estimate in advance the acceleration that accompanies a change in the vehicle attitude that can occur in the future from the driving ability of the driver and the driver's habit. The estimated acceleration is read in step S11 and used as basic data for controlling the back pressure control valve 17 in steps S2 to S6.
[0059]
In the second embodiment using the acceleration predicting means 20A described above, it is possible to achieve the necessary response by performing the pre-reading control, and the accuracy of the control of the differential pressure control by the back pressure control valve 17 can be enhanced.
[0060]
In addition, a function for estimating in advance the maximum acceleration of the vehicle from the road gradient or radius of curvature obtained from wired or wireless, such as a vehicle navigation system, and its length and approach speed is added to the acceleration prediction means 20A. Also good. If the differential pressure target value of the differential pressure control by the back pressure control valve 17 is determined according to the estimated maximum acceleration, the back pressure control can be optimized.
[0061]
In the present embodiment, in addition to the effects (a) to (f) in the first embodiment and the effect (g) in the second embodiment, the following effects can be achieved.
[0062]
(H) Since the acceleration predicting means 20A is provided as an acceleration detecting means for estimating the acceleration from the vehicle speed and the driving operation of the driver, the occurrence of acceleration estimated from the driving operation of the driver can be predicted, and preliminary control is performed. It is possible to optimize the control.
[0063]
(G) The differential pressure between the fuel gas flowing through the anode current collecting plate 7 and the cooling water flowing through the cooling plate 10 according to the distance from the path obstacle by means for measuring the distance from the path obstacle in the traveling direction. Therefore, it is possible to perform preliminary control by estimating the traveling front environment of the vehicle and estimating the driver's desire for stopping or acceleration.
[0064]
(G) Fuel gas flowing through the anode current collector plate 7 in conjunction with the distance to the path obstacle by means for measuring the distance to the path obstacle in the traveling direction and the change in operation of the brake pedal or accelerator pedal of the vehicle Since the differential pressure between the cooling water flowing through the cooling plate 10 is controlled, finer detection can be performed and finer control can be performed.
[0065]
(Sa) a fuel gas that circulates in the anode current collector plate 7 based on an estimated value from a means for estimating a change in posture of the vehicle from a vehicle traveling environment such as a road gradient or a curvature obtained by wire or wireless from the outside of the vehicle; Preliminary control of the differential pressure with the cooling water flowing through the cooling plate enables prediction of the vehicle running posture on the road where future driving is expected, and preliminary control can be performed to optimize the control. .
[0066]
(H) Since the maximum value of the target value of the control is set in proportion to the vehicle acceleration peak estimated from the gradient or curvature of the road from the vehicle posture change estimating means 20A, its distance, and the approaching vehicle speed, Can be achieved.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view of a fuel cell stack in a vehicle equipped with a fuel cell according to an embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of a fuel cell system that is also mounted.
FIG. 3 is a schematic plan view showing a fuel cell stack mounted on a vehicle.
FIG. 4 is a control flowchart of a vehicle equipped with a fuel cell.
FIG. 5 is a time chart showing the operation of a vehicle equipped with a fuel cell.
FIG. 6 is a schematic plan view of a fuel cell vehicle showing a second embodiment of the present invention.
FIG. 7 is a control flowchart of a vehicle equipped with a fuel cell, showing a third embodiment of the present invention.
FIG. 8 is a time chart showing the operation of a vehicle equipped with a fuel cell.
[Explanation of symbols]
1 Fuel cell stack
2 unit cell
3 Polymer electrolyte membrane
4 Oxidant electrode
5 Fuel electrode
6 Oxidant current collector
7 Fuel electrode current collector
8 Humidifying water transmission plate
9 Cooling water flow path
10 Cooling plate
13 Cooling water system
15 Cooling water tank
16 pump
17 Back pressure control valve
20 Acceleration detection means
21 Controller

Claims

A polymer electrolyte membrane is sandwiched between a fuel electrode and an oxidant electrode, and a plurality of unit cells sandwiched between an oxidant electrode current collector plate and a porous fuel electrode current collector plate are stacked, and each unit cell A cooling plate is inserted into the polymer electrolyte membrane, and a part of the cooling water supplied to the cooling plate is supplied to the polymer electrolyte membrane via the porous humidified water transmission plate and the porous fuel electrode current collector plate. Configure the fuel cell stack to humidify the polymer electrolyte membrane,
A fuel cell-equipped vehicle, wherein the fuel electrode is mounted on a vehicle so that the cell stack direction of the fuel cell stack is a front-rear direction of the vehicle with the fuel electrode positioned in front of the polymer electrolyte membrane.

A polymer electrolyte membrane is sandwiched between a fuel electrode and an oxidant electrode, and a plurality of unit cells sandwiched between an oxidant electrode current collector plate and a porous fuel electrode current collector plate are stacked, and each unit cell A cooling plate is inserted into the polymer electrolyte membrane, and a part of the cooling water supplied to the cooling plate is supplied to the polymer electrolyte membrane via the porous humidified water transmission plate and the porous fuel electrode current collector plate. Configure the fuel cell stack to humidify the polymer electrolyte membrane,
The fuel cell stack is mounted on a vehicle such that the cell stacking direction is the front-rear direction of the vehicle,
Means for detecting acceleration in the longitudinal direction of the vehicle in the vehicle;
A vehicle equipped with a fuel cell, wherein a differential pressure between a fuel gas flowing through the anode current collecting plate and a cooling water flowing through a cooling plate is controlled in accordance with an acceleration direction detected by the acceleration detecting means.

The fuel electrode stack is mounted on the vehicle with the fuel electrode positioned behind the polymer electrolyte membrane,
When the acceleration detection means detects vehicle acceleration, the cooling water pressure is increased to reduce the differential pressure between the fuel gas flowing through the anode current collecting plate and the cooling water flowing through the cooling plate. Item 3. A vehicle equipped with a fuel cell according to Item 2.

The fuel electrode stack is mounted on the vehicle with the fuel electrode positioned behind the polymer electrolyte membrane,
When the vehicle deceleration is detected by the acceleration detecting means, the cooling water pressure is decreased to increase the differential pressure between the fuel gas flowing through the anode current collecting plate and the cooling water flowing through the cooling plate. Item 3. A vehicle equipped with a fuel cell according to Item 2.

A polymer electrolyte membrane is sandwiched between a fuel electrode and an oxidant electrode, and a plurality of unit cells sandwiched between an oxidant electrode current collector plate and a porous fuel electrode current collector plate are stacked, and each unit cell A cooling plate is inserted into the polymer electrolyte membrane, and a part of the cooling water supplied to the cooling plate is supplied to the polymer electrolyte membrane via the porous humidified water transmission plate and the porous fuel electrode current collector plate. Configure the fuel cell stack to humidify the polymer electrolyte membrane,
The fuel cell stack is mounted on the vehicle so that the cell stacking direction is orthogonal to the vehicle front-rear direction,
Means for detecting acceleration in the vehicle lateral direction in the vehicle;
The differential pressure between the fuel gas flowing through the anode current collecting plate and the cooling water flowing through the cooling plate is controlled according to the vehicle turning direction, the lateral acceleration detected by the acceleration detecting means, and the power generation tendency. A vehicle equipped with a fuel cell.

6. The fuel cell-equipped vehicle according to claim 2, wherein the acceleration detection means is configured by an acceleration sensor.

6. The fuel cell vehicle according to claim 2, wherein the acceleration detecting means estimates an acceleration from a wheel speed sensor.

6. The fuel cell-equipped vehicle according to claim 2, wherein the acceleration detecting means estimates an acceleration from a vehicle speed and a driving operation of the driver.

The fuel cell-equipped vehicle includes means for measuring a distance from a path obstacle in the traveling direction, and a fuel gas and a cooling plate that circulate in the anode current collecting plate according to the distance from the path obstacle by the distance measuring means The vehicle equipped with a fuel cell according to claim 2 or 5, wherein a differential pressure with respect to the cooling water flowing through the fuel cell is controlled.

The fuel cell-equipped vehicle includes means for measuring a distance from a path obstacle in a traveling direction, and interlocks with a distance from the path obstacle by the distance measuring means and a change in operation of a brake pedal or an accelerator pedal of the vehicle. 6. The fuel cell vehicle according to claim 2, wherein a differential pressure between the fuel gas flowing through the anode current collecting plate and the cooling water flowing through the cooling plate is controlled.

The fuel cell-equipped vehicle includes means for estimating a change in the posture of the vehicle from a vehicle traveling environment having a road gradient or curvature obtained from the outside of the vehicle by wire or wirelessly, and is based on an estimated value from the vehicle posture change estimation means. 6. The fuel cell vehicle according to claim 2, wherein a differential pressure between the fuel gas flowing through the anode current collecting plate and the cooling water flowing through the cooling plate is preliminarily controlled.

The fuel cell-equipped vehicle sets the maximum value of the target value of the control in proportion to the vehicle acceleration peak estimated from the road gradient or curvature from the vehicle posture change estimating means, its distance, and the approaching vehicle speed. The vehicle equipped with a fuel cell according to claim 11.