JP3659005B2

JP3659005B2 - Fuel tank evaporative fuel treatment device

Info

Publication number: JP3659005B2
Application number: JP21761798A
Authority: JP
Inventors: 裕二板倉; 彰夫岩本
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 1998-07-31
Filing date: 1998-07-31
Publication date: 2005-06-15
Anticipated expiration: 2018-07-31
Also published as: JP2000045889A

Description

【０００１】
【発明の属する技術分野】
本発明は、自動車用エンジンにおいて燃料タンクにて発生する蒸発燃料を処理する蒸発燃料処理装置に関する。
【０００２】
【従来の技術】
従来より、自動車用エンジンにおいては、燃料タンクにて発生した蒸発燃料を活性炭を充填したキャニスタに導いて一時的に吸着させ、エンジン運転中にエンジンの吸気系負圧によりキャニスタから蒸発燃料を脱離させて、エンジンに吸入させることで、燃焼処理している（実開平５−９５０号公報等参照）。
【０００３】
【発明が解決しようとする課題】
しかしながら、このような従来の燃料タンクの蒸発燃料処理装置にあっては、燃料タンクにて発生した蒸発燃料の全てを最終的にはエンジンに吸入させて処理するため、多量の蒸発燃料の吸入により、エンジン燃焼に影響を与える場合がある。
【０００４】
また、キャニスタはパージ空気導入用に大気開放口を有しているため、キャニスタが飽和状態になると、それ以降発生した蒸発燃料が車外に放出される恐れがある。
本発明は、このような従来の問題点に鑑み、燃料タンクにて発生した蒸発燃料を凝縮液化して液体燃料として戻すことができるようにして、エンジン燃焼ヘの影響の低減と、蒸発燃料の車外放出の防止とを図ることを目的とする。
【０００５】
【課題を解決するための手段】
このため、請求項１に係る発明では、燃料を貯留し、燃料の給油と消費とが可能な燃料タンクと、燃料タンクとは別に設けられ、燃料タンクより低温度環境下に置かれて、燃料を貯留するサブタンクと、一端が燃料タンクの上部空間に開口し、他端がサブタンク内の燃料中に開口して、燃料タンクの上部空間より蒸発燃料をサブタンク内の燃料中に導いて液化させる蒸発燃料導入通路と、燃料タンク内の燃料とサブタンク内の燃料とを流通可能とする流通手段と、を設けて、燃料タンクの蒸発燃料処理装置を構成し、サブタンク内に蒸発燃料が液化・回収されると、前記流通手段により、サブタンクから燃料タンクへ燃料を戻して、消費可能とし、サブタンク内の液体燃料は、燃料タンク内へ戻すことによってのみ消費可能とした。
【０００６】
請求項２に係る発明では、サブタンクを燃料タンクより低温度環境下に置くために、サブタンクを車両走行風の当たる位置に配置したことを特徴とする。
請求項３に係る発明では、サブタンクを燃料タンクより低温度環境下に置くために、サブタンクを冷却する冷却装置を設けたことを特徴とする。
請求項４に係る発明では、前記流通手段は、サブタンク内における蒸発燃料導入通路の開口端より高位で燃料タンクとサブタンクとを連通させる連通路であることを特徴とする。
【０００７】
請求項５に係る発明では、前記流通手段は、燃料タンクとサブタンクとを比較的低位置で連通させると共に、燃料タンクからサブタンクへの流れのみを許容する一方弁を介装した第１連通路と、燃料タンクとサブタンクとを比較的高位置で連通させると共に、サブタンクから燃料タンクへの流れのみを許容する一方弁を介装した第２連通路とから構成することを特徴とする。
【０００８】
請求項６に係る発明では、前記流通手段は、燃料タンクとサブタンクとを連通させると共に、燃料タンク内の液面高さに応じて開閉制御される電磁弁を介装した連通路であることを特徴とする。
請求項７に係る発明では、サブタンクの上部空間から蒸発燃料を導いて吸着する吸着装置と、該吸着装置に吸着された蒸発燃料を脱離させサブタンク内の燃料中に導いて液化させる第１の脱離装置とを設けたことを特徴とする。
【０００９】
請求項８に係る発明では、サブタンクの上部空間から蒸発燃料を導いて吸着する吸着装置と、該吸着装置に吸着された蒸発燃料をエンジンの吸気系負圧により脱離させエンジンに吸入させる第２の脱離装置とを設けたことを特徴とする。
請求項９に係る発明では、サブタンクの上部空間から蒸発燃料を導いて吸着する吸着装置と、該吸着装置に吸着された蒸発燃料を脱離させサブタンク内の燃料中に導いて液化させる第１の脱離装置と、該吸着装置に吸着された蒸発燃料をエンジンの吸気系負圧により脱離させエンジンに吸入させる第２の脱離装置とを設けたことを特徴とする。
【００１０】
請求項１０に係る発明では、前記第１の脱離装置は、吸着装置に吸着された蒸発燃料を負圧ポンプ又は加熱装置の少なくとも一方を用いて脱離させることを特徴とする。
【００１１】
【発明の効果】
請求項１に係る発明によれば、燃料タンクにて発生した蒸発燃料を、燃料タンクより低温度環境下に置かれたサブタンク内の燃料中に導いて液化させ、燃料タンクに戻すことで、エンジン燃焼ヘの影響の低減と、蒸発燃料の車外放出の防止とを図ることができる。
【００１２】
請求項２に係る発明によれば、サブタンクを車両走行風により冷却することで、低コストで実施できる。
請求項３に係る発明によれば、サブタンクを冷却する冷却装置を設けることで、液化性能を向上できる。
請求項４に係る発明によれば、１本の連通路のみで、低コストで実施できる。
【００１３】
請求項５に係る発明によれば、サブタンク内の液面を十分に確保でき、蒸発燃料と液体燃料との接触時間を長くして、液化性能を向上できる。
請求項６に係る発明によれば、サブタンク内の液面を自由に制御でき、液化性能を向上できる。
請求項７に係る発明によれば、液化しきれずにサブタンク内に溜まった蒸発燃料を再度液化でき、回収効率が向上する。
【００１４】
請求項８に係る発明によれば、液化しきれずにサブタンク内に溜まった蒸発燃料をエンジンに吸入させて確実に処理でき、この場合はエンジンに吸入させる量は少なくて済むので、エンジン燃焼に及ぼす影響も小さい。
請求項９に係る発明によれば、液化しきれずにサブタンク内に溜まった蒸発燃料を再度液化でき、それでも液化しなかった蒸発燃料をエンジンに吸入させて確実に処理できる。
【００１５】
請求項１０に係る発明では、吸着装置に吸着された蒸発燃料を脱離させる際に、負圧ポンプ又は加熱装置の少なくとも一方を用いることで、確実に脱離させることができる。
【００１６】
【発明の実施の形態】
以下に本発明の実施の形態を図面に基づいて説明する。
図１は本発明の第１実施形態を示している。
燃料タンク１とは別に、燃料タンク１より低温度環境下に置かれて、燃料を貯留するサブタンク２を設ける。サブタンク２を燃料タンク１より低温度環境下に置くため、具体的には、例えば図１１に示すように、サブタンク２を車両走行風の当たる位置に配置し、また、車両走行風による冷却効果を増すために、サブタンク２外壁に冷却フィン２ａを設ける。
【００１７】
燃料タンク１とサブタンク２との間には、蒸発燃料導入通路３と、流通手段としての連通路４とを設ける。
蒸発燃料導入通路３は、一端が燃料タンク１の上部空間に開口し、他端がサブタンク２を上下方向に貫通してサブタンク２内の底部近傍の燃料中に開口しており、燃料タンク１の上部空間より蒸発燃料をサブタンク２内の燃料中に導いて液化させる。
【００１８】
連通路４は、燃料タンク１内の燃料とサブタンク２内の燃料とを流通可能とするが、サブタンク２における蒸発燃料導入通路３の開口端より高位で燃料タンク１とサブタンク２とを連通させる。
尚、図中５は燃料タンク１の給油口、６は給油キャップである。
次に作用を説明する。
【００１９】
燃料タンク１内に燃料が給油されると、連通路４により、サブタンク２内の液面高さは燃料タンク１の液面高さと同一になる。
燃料タンク１にてその上部空間に蒸発燃料が発生すると、発生した蒸発燃料は蒸発燃料導入通路３を通って、サブタンク２内の燃料中に導かれ、温度差により冷却されて、凝縮液化する。
【００２０】
凝縮液化されて回収された燃料は、サブタンク２側の液面が高くなることで、連通路４により、少しずつ燃料タンク１に戻される。
燃料タンク１内の燃料が消費されると、サブタンク２内の燃料も減少するが、連通路４の高さ位置より減少することはないので、蒸発燃料導入通路３の開口端は常に燃料中に浸漬されている。
【００２１】
図２は本発明の第２実施形態を示している。
この実施形態では、燃料タンク１内の燃料とサブタンク２内の燃料との流通手段として、燃料タンク１とサブタンク２とを比較的低位置で連通させると共に、燃料タンク１からサブタンク２への流れのみを許容する一方弁８を介装した第１連通路７と、燃料タンク１とサブタンク２とを比較的高位置で連通させると共に、サブタンク２から燃料タンク１への流れのみを許容する一方弁１０を介装した第２連通路９とを設けている。
【００２２】
従って、燃料タンク１内に燃料が給油されると、第１連通路７により、燃料タンク１からサブタンク２へ燃料が流れて、サブタンク２内の液面高さは燃料タンク１の液面高さと同一になる。
蒸発燃料の液化・回収により、サブタンク１内の燃料が増えると、オーバーフロー分が、第２連通路９により、サブタンク２から燃料タンク１へ流れて、燃料タンク１内へ戻される。
【００２３】
従って、この実施形態では、サブタンク２内に常に第２連通路９の高さ位置まで燃料が確保され、蒸発燃料と液体燃料との接触時間を長くして、液化性能をより向上させることができる。
図３は本発明の第３実施形態を示している。
この実施形態では、第１実施形態（図１）に対し、サブタンク２を燃料タンク１より低温度環境下に置くために、サブタンク２の外壁に冷却装置１１を付加している。
【００２４】
冷却装置１１としては、具体的には、表裏の温度差により電位差を発生させ、逆に表裏の電位差により温度差を発生させる熱電変換素子（ペルチェ素子）を用い、表裏に電位差を与えることで、外側の外気温に比べ、内側の温度を下降させて、サブタンク２を冷却する。尚、冷却装置１１としては、これに限らず車両用エアコンの冷媒を用いて冷却するものであってもよい。
【００２５】
また、燃料タンク１内の燃料温度とサブタンク２内の燃料温度とを検出し、温度差が所定値以上確保されるように、冷却装置１１への通電量を制御すると更によい。
図４は本発明の第４実施形態を示している。
この実施形態では、第２実施形態（図２）に対し、サブタンク２を燃料タンク１より低温度環境下に置くために、サブタンク２の外壁に冷却装置１１を付加している。
【００２６】
図５は本発明の第５実施形態を示している。
この実施形態では、第４実施形態（図４）に対し、サブタンク２の上部空間から蒸発燃料を導いて吸着する吸着装置１２と、該吸着装置１２に吸着された蒸発燃料を負圧ポンプ１６により脱離させサブタンク２内の燃料中に導いて液化させる第１の脱離装置１４とを設けている。
【００２７】
吸着装置１２としては、密閉容器内に活性炭等の吸着剤又は高分子吸収剤を充填したものを用い、一端をサブタンク２の上部空間に開口させた蒸発燃料導入通路１３の他端を吸着装置１２に接続する。
第１の脱離装置１４としては、一端を吸着装置１２に接続したパージ通路１５の他端をサブタンク２を上下方向に貫通させてサブタンク２内の底部近傍の燃料中に開口させ、このパージ通路１５の途中に電動式の負圧ポンプ１６を設ける。負圧ポンプ１６は、図１２に具体例を示すようなタービン型ポンプであり、蒸発燃料の吸着による膨張分だけを送ることができるものである。
【００２８】
また、この負圧ポンプ１６の制御のため、吸着装置１２内の蒸発燃料の吸着量を検出すべく、パージ通路１６入口側にＨＣセンサ１７を設けて、その信号をコントロールユニット１８に入力してある。尚、吸着量検出手段としては、ＨＣセンサ１７の他、吸収剤の体積膨張による変位（ストローク）を検出する変位センサなどを用いてもよい。
【００２９】
従って、液化しきれずにサブタンク２の上部空間に溜まった蒸発燃料は蒸発燃料導入通路１３により吸着装置１２に導かれて一時的に吸着される。そして、ＨＣセンサ１７からの信号で吸着装置１２内の吸着量が所定値以上になったことが検出されると、コントロールユニット１８により、負圧ポンプ１６が作動して、吸着装置１２内に吸着されている蒸発燃料を吸引して脱離させ、パージ通路１５により、サブタンク２内の燃料中に導いて液化させることができる。
【００３０】
図６は本発明の第６実施形態を示している。
この実施形態では、第４実施形態（図４）に対し、サブタンク２の上部空間から蒸発燃料を導いて吸着する吸着装置１２と、該吸着装置１２に吸着された蒸発燃料をエンジン２２の吸気系負圧により脱離させエンジン２２に吸入させる第２の脱離装置１９とを設けている。
【００３１】
第２の脱離装置１９としては、一端を吸着装置１２に接続したパージ通路２０の途中にパージ制御弁２１を設け、パージ通路２０の他端をエンジン２２の吸気マニホールド２３に接続してある。
また、このパージ制御弁２１の制御のため、吸着装置１２内の蒸発燃料の吸着量を検出すべく、ＨＣセンサ１７を設けて、その信号をコントロールユニット２４に入力してある。
【００３２】
従って、液化しきれずにサブタンク２の上部空間に溜まった蒸発燃料は蒸発燃料導入通路１３により吸着装置１２に導かれて一時的に吸着される。そして、ＨＣセンサ１７からの信号で吸着装置１２内の吸着量が所定値以上になったことが検出されると、コントロールユニット２４により、パージ制御弁２１が開き、エンジン２２の吸気系負圧が吸着装置１２に作用する結果、吸着装置１２内に吸着されている蒸発燃料が脱離し、パージ通路２０により、エンジン２２に吸入されて、燃焼処理される。
【００３３】
このように液化しきれずにサブタンク２の上部空間に溜まった蒸発燃料のみをエンジン２２に吸入させて処理するので、エンジン燃焼に与える影響を少なくできる。
図７は本発明の第７実施形態を示している。
この実施形態では、第４実施形態（図４）に対し、サブタンク２の上部空間から蒸発燃料を導いて吸着する吸着装置１２と、該吸着装置１２に吸着された蒸発燃料を負圧ポンプ１６により脱離させサブタンク２内の燃料中に導いて液化させる第１の脱離装置１４と、該吸着装置１２に吸着された蒸発燃料をエンジン２２の吸気系負圧により脱離させエンジン２２に吸入させる第２の脱離装置１９とを設けている。
【００３４】
また、第１の脱離装置１４の負圧ポンプ１６と第２の脱離装置１９のパージ制御弁２１の制御のため、吸着装置１２内の蒸発燃料の吸着量を検出すべく、ＨＣセンサ１７を設けて、その信号をコントロールユニット２５に入力してある。
従って、液化しきれずにサブタンク２の上部空間に溜まった蒸発燃料は蒸発燃料導入通路１３により吸着装置１２に導かれて一時的に吸着される。そして、ＨＣセンサ１７からの信号で吸着装置１２内の吸着量が第１の所定値以上になったことが検出されると、コントロールユニット２５により、負圧ポンプ１６が作動して、吸着装置１２内に吸着されている蒸発燃料を吸引して脱離させ、パージ通路１５により、サブタンク２内の燃料中に導いて液化させる。
【００３５】
また、ＨＣセンサ１７からの信号で吸着装置１２内の吸着量が第２の所定値以上になったことが検出されると、コントロールユニット２５により、パージ制御弁２１が開き、エンジン２２の吸気系負圧が吸着装置１２に作用する結果、吸着装置１２内に吸着されている蒸発燃料が脱離し、パージ通路２０により、エンジン２２に吸入されて、燃焼処理される。
【００３６】
図８は本発明の第８実施形態を示している。
この実施形態では、第５実施形態（図５）に対し、吸着装置１２への蒸発燃料導入通路１３の途中に、負圧カット機構付きの一方弁２６を設けている。
この一方弁２６は、図１３に具体例を示すように、サブタンク２側から吸着装置１２側へ蒸発燃料が流れるときのみ、第１弁体２６ａが開いて、その流れを許容するのみならず、吸着装置１２側に負圧が発生すると、第２弁体２６ｂが閉じて、負圧の伝達をカットする。
【００３７】
従って、負圧ポンプ１６により吸着装置１２内の蒸発燃料を脱離させる際に、その負圧の伝達を一方弁２６の位置でカットでき、サブタンク２に過大な負圧が作用するのを確実に回避できる。
図９は本発明の第９実施形態を示している。
この実施形態では、第７実施形態（図７）に対し、コントロールユニット２７に燃料タンク１内の液面高さを検出する燃料レベルゲージ２８の信号を入力して、コントロールユニット２７にて、燃料レベルゲージ２８の信号とＨＣセンサ１７の信号とに基づいて、負圧ポンプ１６及びパージ制御弁２１の作動を制御するようにしている。
【００３８】
具体的には、例えば、燃料タンク１内の燃料レベルが高いときは、燃料タンク１からの蒸発燃料の発生量が多いので、ＨＣセンサ１７の信号により吸着装置１２の吸着量が所定値以上になったときに、パージ制御弁２１を開いて、サブタンク２内の蒸発燃料をエンジン２２に吸入させる。
逆に、燃料レベルが低いときは、燃料タンク１からの蒸発燃料の発生量が少ないので、ＨＣセンサ１７の信号により吸着装置１２の吸着量が所定値以上になったときに、負圧ポンプ１６を作動させて、サブタンク２内の蒸発燃料の液化回収を図る。
【００３９】
図１０は本発明の第１０実施形態を示している。
この実施形態では、第５実施形態（図５）に対し、燃料タンク１内の燃料とサブタンク２内の燃料との流通手段として、燃料タンク１とサブタンク２とを連通させると共に、燃料タンク１内の液面高さに応じて開閉制御される電磁弁３０を介装した連通路２９を設けている。
【００４０】
すなわち、燃料レベルゲージ２８の信号をコントロールユニット３１に入力し、コントロールユニット３１にて、燃料タンク１の液面高さが所定値以上のときに、電磁弁３０を開き、所定値未満になると、電磁弁３０を閉じるようにしている。
従って、燃料タンク１内に燃料が給油されて、燃料タンク１内の液面が上昇し、所定値以上になると、電磁弁３０が開き、連通路２９により、燃料タンク１からサブタンク２へ燃料が流れて、サブタンク２内の液面高さは燃料タンク１の液面高さと同一になる。
【００４１】
蒸発燃料の液化・回収により、サブタンク１内の燃料が増えると、連通路２９により、サブタンク２から燃料タンク１へ流れて、燃料タンク１内へ戻される。燃料タンク１内の燃料が消費されて、燃料タンク１内の液面が下降し、所定値未満になると、電磁弁３０が閉じる。これにより、サブタンク２内の液面高さの減少が回避され、必要最低限の液面高さを確保して、液化性能をより向上させることができる。
【００４２】
尚、第５実施形態（図５）、第７実施形態（図７）、第８実施形態（図８）、第９実施形態（図９）、第１０実施形態（図１０）では、第１の脱離装置１４により、吸着装置１２に吸着された蒸発燃料を脱離させる際に、負圧ポンプ１６を用いているが、吸着装置１２に対する加熱装置を用いてもよく、あるいは両者を併用してもよい。
【図面の簡単な説明】
【図１】本発明の第１実施形態を示すシステム図
【図２】本発明の第２実施形態を示すシステム図
【図３】本発明の第３実施形態を示すシステム図
【図４】本発明の第４実施形態を示すシステム図
【図５】本発明の第５実施形態を示すシステム図
【図６】本発明の第６実施形態を示すシステム図
【図７】本発明の第７実施形態を示すシステム図
【図８】本発明の第８実施形態を示すシステム図
【図９】本発明の第９実施形態を示すシステム図
【図１０】本発明の第１０実施形態を示すシステム図
【図１１】燃料タンク及びサブタンクの配置例を示す図
【図１２】負圧ポンプの具体例を示す図
【図１３】負圧カット機構付き一方弁の具体例を示す図
【符号の説明】
１燃料タンク
２サブタンク
３蒸発燃料導入通路
４連通路
７第２連通路
８一方弁
９第１連通路
１０一方弁
１１冷却装置
１２吸着装置
１３蒸発燃料導入通路
１４第１の脱離装置
１５パージ通路
１６負圧ポンプ
１７ＨＣセンサ
１８コントロールユニット
１９第２の脱離装置
２０パージ通路
２１パージ制御弁
２２エンジン
２３吸気マニホールド
２４コントロールユニット
２５コントロールユニット
２６負圧カット機構付きの一方弁
２７コントロールユニット
２８燃料レベルゲージ
２９連通路
３０電磁弁
３１コントロールユニット[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an evaporated fuel processing apparatus for processing evaporated fuel generated in a fuel tank in an automobile engine.
[0002]
[Prior art]
Conventionally, in an automobile engine, the evaporated fuel generated in the fuel tank is guided to a canister filled with activated carbon and temporarily adsorbed, and the evaporated fuel is desorbed from the canister by the negative pressure of the intake air of the engine during engine operation. Thus, the combustion process is performed by inhaling the engine (see Japanese Utility Model Laid-Open No. 5-950).
[0003]
[Problems to be solved by the invention]
However, in such a conventional evaporative fuel processing apparatus for a fuel tank, since all the evaporative fuel generated in the fuel tank is finally sucked into the engine for processing, a large amount of evaporative fuel is inhaled. May affect engine combustion.
[0004]
Further, since the canister has an air opening for introducing purge air, when the canister is saturated, the evaporated fuel generated thereafter may be discharged outside the vehicle.
In view of such a conventional problem, the present invention enables the evaporated fuel generated in the fuel tank to be condensed and liquefied and returned as a liquid fuel, thereby reducing the influence on engine combustion and evaporating fuel. The purpose is to prevent emission outside the vehicle.
[0005]
[Means for Solving the Problems]
For this reason, in the invention according to claim 1, a fuel tank that stores fuel and is capable of refueling and consuming fuel is provided separately from the fuel tank, and is placed in a lower temperature environment than the fuel tank. A subtank that stores the fuel, and one end that opens into the upper space of the fuel tank and the other end that opens into the fuel in the subtank, and evaporates fuel from the upper space of the fuel tank into the fuel in the subtank and liquefies. A fuel introduction passage and a flow means for allowing the fuel in the fuel tank and the fuel in the sub tank to flow are provided to constitute an evaporative fuel treatment device for the fuel tank, and the evaporated fuel is liquefied and recovered in the sub tank. Then, the circulation means allows the fuel to be returned from the sub tank to the fuel tank and can be consumed, and the liquid fuel in the sub tank can be consumed only by returning it to the fuel tank.
[0006]
The invention according to claim 2 is characterized in that the sub tank is arranged at a position where the vehicle traveling wind hits in order to place the sub tank in a lower temperature environment than the fuel tank.
The invention according to claim 3 is characterized in that a cooling device for cooling the sub tank is provided in order to place the sub tank in a lower temperature environment than the fuel tank.
The invention according to claim 4 is characterized in that the flow means is a communication passage that allows the fuel tank and the sub tank to communicate with each other at a position higher than the open end of the evaporated fuel introduction passage in the sub tank.
[0007]
In the invention according to claim 5, the flow means communicates the fuel tank and the sub-tank at a relatively low position, and includes a first communication path having a one-way valve that allows only the flow from the fuel tank to the sub-tank. The fuel tank and the sub-tank communicate with each other at a relatively high position, and the second tank is provided with a one-way valve that allows only the flow from the sub-tank to the fuel tank.
[0008]
In the invention according to claim 6, the flow means is a communication path that connects the fuel tank and the sub-tank, and is provided with an electromagnetic valve that is controlled to open and close according to the liquid level in the fuel tank. Features.
In the invention according to claim 7, there is provided an adsorption device that guides and adsorbs the evaporated fuel from the upper space of the sub tank, and a first method for desorbing the evaporated fuel adsorbed by the adsorption device and introducing it into the fuel in the sub tank to be liquefied. A desorption device is provided.
[0009]
In the invention according to claim 8, the adsorbing device that guides and adsorbs the evaporated fuel from the upper space of the sub-tank, and the second that causes the evaporated fuel adsorbed by the adsorbing device to be desorbed by the intake system negative pressure and sucked into the engine. The detaching apparatus is provided.
In the invention according to claim 9, there is provided an adsorbing device that guides and adsorbs the evaporated fuel from the upper space of the sub tank, and a first method for desorbing the evaporated fuel adsorbed by the adsorbing device and introducing it into the fuel in the sub tank for liquefaction. A desorption device and a second desorption device for desorbing the evaporated fuel adsorbed by the adsorbing device by an intake system negative pressure of the engine and sucking the fuel into the engine are provided.
[0010]
The invention according to claim 10 is characterized in that the first desorption device desorbs the evaporated fuel adsorbed by the adsorption device using at least one of a negative pressure pump and a heating device.
[0011]
【The invention's effect】
According to the first aspect of the invention, the evaporated fuel generated in the fuel tank is led into the fuel in the sub-tank placed in a lower temperature environment than the fuel tank, liquefied, and returned to the fuel tank, so that the engine It is possible to reduce the influence on combustion and to prevent evaporative fuel from being released outside the vehicle.
[0012]
According to the invention which concerns on Claim 2, it can implement at low cost by cooling a subtank with a vehicle running wind.
According to the invention which concerns on Claim 3, liquefying performance can be improved by providing the cooling device which cools a subtank.
According to the invention which concerns on Claim 4, it can implement at low cost only with one communicating path.
[0013]
According to the invention which concerns on Claim 5, the liquid level in a subtank can fully be ensured, the contact time of evaporative fuel and liquid fuel can be lengthened, and liquefaction performance can be improved.
According to the invention which concerns on Claim 6, the liquid level in a sub tank can be freely controlled and liquefaction performance can be improved.
According to the seventh aspect of the invention, the evaporated fuel that has not been liquefied and has accumulated in the sub tank can be liquefied again, and the recovery efficiency is improved.
[0014]
According to the eighth aspect of the invention, the evaporated fuel accumulated in the sub-tank without being completely liquefied can be reliably sucked into the engine, and in this case, the amount of the fuel sucked into the engine can be reduced. The impact is small.
According to the ninth aspect of the present invention, the evaporated fuel accumulated in the sub-tank without being completely liquefied can be liquefied again, and the evaporated fuel that has not been liquefied can be sucked into the engine and reliably processed.
[0015]
In the invention according to claim 10, when the evaporated fuel adsorbed by the adsorption device is desorbed, it can be desorbed reliably by using at least one of a negative pressure pump and a heating device.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a first embodiment of the present invention.
In addition to the fuel tank 1, a sub tank 2 is provided which is placed in a lower temperature environment than the fuel tank 1 and stores fuel. In order to place the sub-tank 2 in a lower temperature environment than the fuel tank 1, specifically, as shown in FIG. 11, for example, the sub-tank 2 is disposed at a position where the vehicle traveling wind strikes and the cooling effect by the vehicle traveling wind is exerted. In order to increase, cooling fins 2 a are provided on the outer wall of the sub tank 2.
[0017]
Between the fuel tank 1 and the sub tank 2, an evaporative fuel introduction passage 3 and a communication passage 4 as a circulation means are provided.
One end of the evaporative fuel introduction passage 3 opens into the upper space of the fuel tank 1, and the other end passes through the sub tank 2 in the vertical direction and opens into the fuel near the bottom of the sub tank 2. The evaporative fuel is introduced into the fuel in the sub tank 2 from the upper space to be liquefied.
[0018]
The communication path 4 allows the fuel in the fuel tank 1 and the fuel in the sub tank 2 to flow, but allows the fuel tank 1 and the sub tank 2 to communicate with each other at a position higher than the opening end of the evaporated fuel introduction path 3 in the sub tank 2.
In the figure, 5 is a fuel filler port of the fuel tank 1 and 6 is a fuel cap.
Next, the operation will be described.
[0019]
When fuel is supplied into the fuel tank 1, the liquid level in the sub tank 2 becomes the same as the liquid level in the fuel tank 1 by the communication path 4.
When evaporative fuel is generated in the upper space of the fuel tank 1, the generated evaporative fuel passes through the evaporative fuel introduction passage 3, is led into the fuel in the sub tank 2, is cooled by the temperature difference, and is condensed and liquefied.
[0020]
The fuel recovered after being condensed and liquefied is gradually returned to the fuel tank 1 through the communication path 4 as the liquid level on the sub tank 2 side becomes higher.
When the fuel in the fuel tank 1 is consumed, the fuel in the sub-tank 2 also decreases. However, since the fuel tank 1 does not decrease from the height position of the communication path 4, the open end of the evaporative fuel introduction path 3 is always in the fuel. Soaked.
[0021]
FIG. 2 shows a second embodiment of the present invention.
In this embodiment, as a means for distributing the fuel in the fuel tank 1 and the fuel in the sub tank 2, the fuel tank 1 and the sub tank 2 are communicated at a relatively low position, and only the flow from the fuel tank 1 to the sub tank 2 is performed. The one-way valve 10 that allows the first communication passage 7 that includes the one-valve 8 to communicate with the fuel tank 1 and the sub-tank 2 at a relatively high position and that allows only the flow from the sub-tank 2 to the fuel tank 1. A second communication passage 9 is provided.
[0022]
Therefore, when fuel is supplied into the fuel tank 1, the fuel flows from the fuel tank 1 to the sub tank 2 through the first communication passage 7, and the liquid level in the sub tank 2 is equal to the liquid level of the fuel tank 1. Be the same.
When the fuel in the sub tank 1 increases due to the liquefaction / recovery of the evaporated fuel, the overflow amount flows from the sub tank 2 to the fuel tank 1 through the second communication passage 9 and is returned to the fuel tank 1.
[0023]
Therefore, in this embodiment, the fuel is always ensured up to the height position of the second communication path 9 in the sub-tank 2, and the contact time between the evaporated fuel and the liquid fuel can be lengthened to further improve the liquefaction performance. .
FIG. 3 shows a third embodiment of the present invention.
In this embodiment, a cooling device 11 is added to the outer wall of the sub tank 2 in order to place the sub tank 2 in a lower temperature environment than the fuel tank 1 compared to the first embodiment (FIG. 1).
[0024]
Specifically, as the cooling device 11, by using a thermoelectric conversion element (Peltier element) that generates a potential difference due to a temperature difference between the front and back sides, and conversely generates a temperature difference due to a potential difference between the front and back sides, The sub-tank 2 is cooled by lowering the inner temperature as compared with the outside outside air temperature. The cooling device 11 is not limited to this, and may be one that cools using a refrigerant of a vehicle air conditioner.
[0025]
It is further preferable to detect the fuel temperature in the fuel tank 1 and the fuel temperature in the sub-tank 2 and to control the amount of current supplied to the cooling device 11 so that the temperature difference is secured to a predetermined value or more.
FIG. 4 shows a fourth embodiment of the present invention.
In this embodiment, a cooling device 11 is added to the outer wall of the sub tank 2 in order to place the sub tank 2 in a lower temperature environment than the fuel tank 1 compared to the second embodiment (FIG. 2).
[0026]
FIG. 5 shows a fifth embodiment of the present invention.
In this embodiment, compared to the fourth embodiment (FIG. 4), an adsorbing device 12 that guides and adsorbs the evaporated fuel from the upper space of the sub tank 2, and the evaporated fuel adsorbed on the adsorbing device 12 by the negative pressure pump 16. A first desorption device 14 is provided which is desorbed and led into the fuel in the sub tank 2 to be liquefied.
[0027]
As the adsorbing device 12, an airtight container filled with an adsorbent such as activated carbon or a polymer absorbent is used, and the other end of the evaporative fuel introduction passage 13 having one end opened to the upper space of the sub tank 2 is used as the adsorbing device 12. Connect to.
As the first desorption device 14, the other end of the purge passage 15 having one end connected to the adsorption device 12 is passed through the sub tank 2 in the vertical direction to open into the fuel near the bottom in the sub tank 2, and this purge passage An electric negative pressure pump 16 is provided in the middle of 15. The negative pressure pump 16 is a turbine type pump as shown in a specific example in FIG. 12, and can send only the expansion due to the adsorption of the evaporated fuel.
[0028]
In order to control the negative pressure pump 16, an HC sensor 17 is provided on the inlet side of the purge passage 16 in order to detect the adsorption amount of the evaporated fuel in the adsorption device 12, and the signal is input to the control unit 18. is there. As the adsorption amount detection means, in addition to the HC sensor 17, a displacement sensor that detects a displacement (stroke) due to volume expansion of the absorbent may be used.
[0029]
Therefore, the evaporated fuel that has not been liquefied and has accumulated in the upper space of the sub tank 2 is guided to the adsorption device 12 by the evaporated fuel introduction passage 13 and temporarily adsorbed. When it is detected from the signal from the HC sensor 17 that the amount of adsorption in the adsorption device 12 has become a predetermined value or more, the negative pressure pump 16 is activated by the control unit 18 and is adsorbed in the adsorption device 12. The evaporated fuel is sucked and desorbed, and can be led into the fuel in the sub tank 2 by the purge passage 15 to be liquefied.
[0030]
FIG. 6 shows a sixth embodiment of the present invention.
In this embodiment, compared to the fourth embodiment (FIG. 4), an adsorbing device 12 that guides and adsorbs evaporated fuel from the upper space of the sub-tank 2, and the evaporated fuel adsorbed by the adsorbing device 12 in the intake system of the engine 22. A second desorption device 19 that is desorbed by negative pressure and sucked into the engine 22 is provided.
[0031]
As the second desorption device 19, a purge control valve 21 is provided in the middle of the purge passage 20 whose one end is connected to the adsorption device 12, and the other end of the purge passage 20 is connected to the intake manifold 23 of the engine 22.
In order to control the purge control valve 21, an HC sensor 17 is provided to detect the adsorption amount of the evaporated fuel in the adsorption device 12, and its signal is input to the control unit 24.
[0032]
Therefore, the evaporated fuel that has not been liquefied and has accumulated in the upper space of the sub tank 2 is guided to the adsorption device 12 by the evaporated fuel introduction passage 13 and temporarily adsorbed. When it is detected from the signal from the HC sensor 17 that the amount of adsorption in the adsorption device 12 exceeds a predetermined value, the control unit 24 opens the purge control valve 21 and the intake system negative pressure of the engine 22 is reduced. As a result of acting on the adsorption device 12, the evaporated fuel adsorbed in the adsorption device 12 is desorbed, and is sucked into the engine 22 through the purge passage 20 and is subjected to combustion processing.
[0033]
As described above, only the evaporated fuel that has not been liquefied and has accumulated in the upper space of the sub-tank 2 is sucked into the engine 22 and processed, so that the influence on engine combustion can be reduced.
FIG. 7 shows a seventh embodiment of the present invention.
In this embodiment, compared to the fourth embodiment (FIG. 4), an adsorbing device 12 that guides and adsorbs the evaporated fuel from the upper space of the sub tank 2, and the evaporated fuel adsorbed on the adsorbing device 12 by the negative pressure pump 16. A first desorbing device 14 that is desorbed and led into the fuel in the sub-tank 2 and liquefies, and the evaporated fuel adsorbed by the adsorbing device 12 is desorbed by the intake system negative pressure of the engine 22 and sucked into the engine 22. A second desorption device 19 is provided.
[0034]
In order to control the negative pressure pump 16 of the first desorption device 14 and the purge control valve 21 of the second desorption device 19, the HC sensor 17 is used to detect the adsorption amount of the evaporated fuel in the adsorption device 12. The signal is input to the control unit 25.
Therefore, the evaporated fuel that has not been liquefied and has accumulated in the upper space of the sub tank 2 is guided to the adsorption device 12 by the evaporated fuel introduction passage 13 and temporarily adsorbed. When it is detected from the signal from the HC sensor 17 that the amount of adsorption in the adsorption device 12 has become equal to or greater than the first predetermined value, the negative pressure pump 16 is activated by the control unit 25 and the adsorption device 12 is activated. The evaporated fuel adsorbed inside is sucked and desorbed, and led to the fuel in the sub tank 2 by the purge passage 15 to be liquefied.
[0035]
Further, when it is detected from the signal from the HC sensor 17 that the amount of adsorption in the adsorption device 12 has exceeded the second predetermined value, the purge control valve 21 is opened by the control unit 25 and the intake system of the engine 22 is opened. As a result of the negative pressure acting on the adsorption device 12, the evaporated fuel adsorbed in the adsorption device 12 is desorbed, and is sucked into the engine 22 through the purge passage 20 for combustion processing.
[0036]
FIG. 8 shows an eighth embodiment of the present invention.
In this embodiment, in contrast to the fifth embodiment (FIG. 5), a one-way valve 26 with a negative pressure cut mechanism is provided in the middle of the evaporated fuel introduction passage 13 to the adsorption device 12.
As shown in a specific example in FIG. 13, the one-way valve 26 not only allows the first valve body 26 a to open and allow the flow only when the evaporated fuel flows from the sub tank 2 side to the adsorption device 12 side, When a negative pressure is generated on the side of the suction device 12, the second valve body 26b is closed and the transmission of the negative pressure is cut.
[0037]
Accordingly, when the evaporated fuel in the adsorption device 12 is desorbed by the negative pressure pump 16, the transmission of the negative pressure can be cut at the position of the one-way valve 26, and it is ensured that an excessive negative pressure acts on the sub tank 2. Can be avoided.
FIG. 9 shows a ninth embodiment of the present invention.
In this embodiment, in contrast to the seventh embodiment (FIG. 7), a signal of a fuel level gauge 28 for detecting the liquid level in the fuel tank 1 is input to the control unit 27, and the control unit 27 The operation of the negative pressure pump 16 and the purge control valve 21 is controlled based on the signal from the level gauge 28 and the signal from the HC sensor 17.
[0038]
Specifically, for example, when the fuel level in the fuel tank 1 is high, the amount of evaporated fuel generated from the fuel tank 1 is large, so that the adsorption amount of the adsorption device 12 exceeds a predetermined value by the signal of the HC sensor 17. When this happens, the purge control valve 21 is opened, and the evaporated fuel in the sub tank 2 is sucked into the engine 22.
On the other hand, when the fuel level is low, the amount of evaporated fuel generated from the fuel tank 1 is small. Therefore, when the adsorption amount of the adsorption device 12 exceeds a predetermined value by the signal of the HC sensor 17, the negative pressure pump 16 Is operated to liquefy and recover the evaporated fuel in the sub-tank 2.
[0039]
FIG. 10 shows a tenth embodiment of the present invention.
In this embodiment, as compared with the fifth embodiment (FIG. 5), the fuel tank 1 and the sub-tank 2 are communicated with each other as a means for distributing the fuel in the fuel tank 1 and the fuel in the sub-tank 2. A communication passage 29 is provided with an electromagnetic valve 30 that is controlled to open and close according to the liquid level.
[0040]
That is, when the signal of the fuel level gauge 28 is input to the control unit 31 and the control unit 31 opens the electromagnetic valve 30 when the liquid level of the fuel tank 1 is greater than or equal to a predetermined value, The electromagnetic valve 30 is closed.
Accordingly, when fuel is supplied into the fuel tank 1 and the liquid level in the fuel tank 1 rises and exceeds a predetermined value, the electromagnetic valve 30 is opened, and fuel flows from the fuel tank 1 to the sub tank 2 through the communication path 29. As a result, the liquid level in the sub tank 2 becomes the same as the liquid level in the fuel tank 1.
[0041]
When the fuel in the sub-tank 1 increases due to the liquefaction / recovery of the evaporated fuel, it flows from the sub-tank 2 to the fuel tank 1 through the communication passage 29 and is returned to the fuel tank 1. When the fuel in the fuel tank 1 is consumed and the liquid level in the fuel tank 1 falls and becomes less than a predetermined value, the electromagnetic valve 30 is closed. Thereby, a decrease in the liquid level in the sub-tank 2 is avoided, and the minimum liquid level can be ensured to improve the liquefaction performance.
[0042]
In the fifth embodiment (FIG. 5), the seventh embodiment (FIG. 7), the eighth embodiment (FIG. 8), the ninth embodiment (FIG. 9), and the tenth embodiment (FIG. 10), When the evaporative fuel adsorbed by the adsorption device 12 is desorbed by the desorption device 14, the negative pressure pump 16 is used. However, a heating device for the adsorption device 12 may be used, or both may be used in combination. May be.
[Brief description of the drawings]
1 is a system diagram showing a first embodiment of the present invention. FIG. 2 is a system diagram showing a second embodiment of the present invention. FIG. 3 is a system diagram showing a third embodiment of the present invention. FIG. 5 is a system diagram showing a fifth embodiment of the invention. FIG. 6 is a system diagram showing a sixth embodiment of the invention. FIG. 7 is a system diagram showing the sixth embodiment of the invention. FIG. 8 is a system diagram showing the eighth embodiment of the present invention. FIG. 9 is a system diagram showing the ninth embodiment of the present invention. FIG. 10 is a system diagram showing the tenth embodiment of the present invention. 11 is a view showing an example of arrangement of a fuel tank and a sub tank. FIG. 12 is a view showing a specific example of a negative pressure pump. FIG. 13 is a view showing a specific example of a one-way valve with a negative pressure cut mechanism.
DESCRIPTION OF SYMBOLS 1 Fuel tank 2 Sub tank 3 Evaporated fuel introduction channel 4 Communication channel 7 Second communication channel 8 One valve 9 First communication channel 10 One valve 11 Cooling device 12 Adsorbing device 13 Evaporated fuel introduction channel 14 First desorption device 15 Purge channel 16 Negative pressure pump 17 HC sensor 18 Control unit 19 Second desorption device 20 Purge passage 21 Purge control valve 22 Engine 23 Intake manifold 24 Control unit 25 Control unit 26 One valve 27 with negative pressure cut mechanism Control unit 28 Fuel level Gauge 29 Communication path 30 Solenoid valve 31 Control unit

Claims

A fuel tank for storing fuel and capable of refueling and consuming fuel;
A sub tank that is provided separately from the fuel tank, is placed in a lower temperature environment than the fuel tank, and stores fuel;
An evaporative fuel introduction passage having one end opened in the upper space of the fuel tank, the other end opened in the fuel in the sub tank, and the evaporative fuel is led from the upper space of the fuel tank into the fuel in the sub tank to be liquefied;
A circulation means for allowing the fuel in the fuel tank and the fuel in the sub tank to flow ,
When the evaporated fuel is liquefied and recovered in the sub tank, the fuel can be consumed by returning the fuel from the sub tank to the fuel tank by the distribution means, and the liquid fuel in the sub tank can be consumed only by returning it to the fuel tank. An evaporative fuel treatment apparatus for a fuel tank, characterized by comprising:

2. The evaporative fuel treatment apparatus for a fuel tank according to claim 1, wherein the sub tank is disposed at a position where the vehicle traveling wind hits in order to place the sub tank in a lower temperature environment than the fuel tank.

2. The evaporative fuel treatment apparatus for a fuel tank according to claim 1, further comprising a cooling device for cooling the sub tank so that the sub tank is placed in a lower temperature environment than the fuel tank.

The said distribution | circulation means is a communicating path which connects a fuel tank and a subtank above the opening end of the evaporative fuel introduction channel | path in a subtank, The any one of Claims 1-3 characterized by the above-mentioned. Evaporative fuel treatment device for fuel tank.

The distribution means compares the fuel tank and the sub-tank with the first communication path having a one-way valve that allows the fuel tank and the sub-tank to communicate with each other at a relatively low position and allows only the flow from the fuel tank to the sub-tank. 4. A second communication passage having a one-way valve for allowing only a flow from the sub-tank to the fuel tank, and a second communication path that allows communication at a target high position. The evaporative fuel processing apparatus of the fuel tank described in 1.

The said distribution | circulation means is a communicating path which connected the fuel tank and the sub tank, and was equipped with the solenoid valve by which opening / closing control was carried out according to the liquid level height in a fuel tank. Item 5. The fuel vapor processing apparatus for a fuel tank according to any one of Items 3 to 5.

An adsorption device that guides and adsorbs evaporated fuel from the upper space of the sub-tank, and a first desorption device that desorbs the evaporated fuel adsorbed by the adsorption device and introduces it into the fuel in the sub-tank to be liquefied. The evaporative fuel processing apparatus of the fuel tank as described in any one of Claims 1-6 characterized by these.

An adsorbing device that guides and adsorbs the evaporated fuel from the upper space of the sub-tank, and a second desorbing device that desorbs the evaporated fuel adsorbed by the adsorbing device by the negative pressure of the intake system of the engine and sucks it into the engine are provided. The evaporative fuel processing apparatus of the fuel tank as described in any one of Claims 1-6 characterized by the above-mentioned.

An adsorbing device that guides and adsorbs the evaporated fuel from the upper space of the sub tank, a first desorbing device that desorbs the evaporated fuel adsorbed by the adsorbing device and introduces it into the fuel in the sub tank, and the adsorbing device 7. A second desorption device that desorbs the evaporated fuel adsorbed on the engine by a negative pressure of the intake system of the engine and sucks the fuel into the engine is provided. 7. Fuel tank evaporative fuel treatment device.

The fuel tank according to claim 7 or 9, wherein the first desorption device desorbs the evaporated fuel adsorbed by the adsorption device using at least one of a negative pressure pump and a heating device. Evaporative fuel processing device.