JP2003080960A - Fuel vapor generation restricting device for fuel tank in vehicle - Google Patents
Fuel vapor generation restricting device for fuel tank in vehicleInfo
- Publication number
- JP2003080960A JP2003080960A JP2002132573A JP2002132573A JP2003080960A JP 2003080960 A JP2003080960 A JP 2003080960A JP 2002132573 A JP2002132573 A JP 2002132573A JP 2002132573 A JP2002132573 A JP 2002132573A JP 2003080960 A JP2003080960 A JP 2003080960A
- Authority
- JP
- Japan
- Prior art keywords
- way valve
- fuel tank
- pressure
- canister
- fuel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Cooling, Air Intake And Gas Exhaust, And Fuel Tank Arrangements In Propulsion Units (AREA)
- Supplying Secondary Fuel Or The Like To Fuel, Air Or Fuel-Air Mixtures (AREA)
Abstract
Description
【発明の詳細な説明】
【０００１】
【発明の属する技術分野】本発明は、燃料タンクとキャ
ニスタとを、燃料タンクの内圧が増加したときに開弁す
る正圧用一方向弁と、燃料タンクの内圧が減少したとき
に開弁する負圧用一方向弁とを有する二方向弁を介して
接続した車両用燃料タンクの燃料蒸気発生抑制装置に関
する。
【０００２】
【従来の技術】自動車の燃料タンクとキャニスタとの間
には正圧用一方向弁および負圧用一方向弁を逆方向に組
み合わせた二方向弁が配置されており、燃料タンクの温
度が上昇して内圧が高くなると、正圧用一方向弁が開弁
して燃料タンク内の燃料蒸気がキャニスタにチャージさ
れ、燃料蒸気の大気への放出が阻止される。また燃料タ
ンクの温度が低下して内圧が低くなると、負圧用一方向
弁が開弁して大気がキャニスタを経て燃料タンク内に吸
入され、負圧による燃料タンクの変形が阻止される。従
来の二方向弁は、正圧用一方向弁の開弁圧が大気圧より
もやや高い圧力（例えば、２ｋＰａ程度）に設定され、
負圧用一方向弁の開弁圧が大気圧よりも僅かに低い圧力
（例えば、−１．３ｋＰａ程度）に設定されていた。
【０００３】
【発明が解決しようとする課題】ところで、キャニスタ
にチャージされた燃料蒸気はエンジンの運転時に吸気系
にパージされるが、自動車を使用せずに数日間に亘って
放置する場合にはキャニスタにチャージされた燃料蒸気
がパージされないため、正圧用一方向弁が開弁する度に
キャニスタのチャージ量が積算され、やがてキャニスタ
がフルチャージ状態になってそれ以上の燃料蒸気をチャ
ージできなくなる可能性がある。
【０００４】本発明は前述の事情に鑑みてなされたもの
で、エンジンを運転せずに自動車を長期に亘って放置す
る場合にキャニスタのチャージ量を最小限に抑えること
を目的とする。
【０００５】
【課題を解決するための手段】上記目的を達成するため
に、請求項１に記載された発明によれば、燃料タンクと
キャニスタとを、燃料タンクの内圧が増加したときに開
弁する正圧用一方向弁と、燃料タンクの内圧が減少した
ときに開弁する負圧用一方向弁とを有する二方向弁を介
して接続した車両用燃料タンクの燃料蒸気発生抑制装置
において、前記負圧用一方向弁が開弁する燃料タンクの
内圧を−７ｋＰａ以下の任意の点に設定したことを特徴
とする車両用燃料タンクの燃料蒸気発生抑制装置が提案
される。
【０００６】上記構成によれば、燃料タンクおよびキャ
ニスタ間に配置した二方向弁の負圧用一方向弁が開弁す
る燃料タンクの内圧を従来よりも低い−７ｋＰａ以下の
任意の点に設定したので、温度上昇時に負圧用一方向弁
が閉弁してから正圧用一方向弁が開弁するまで時間が従
来よりも長くなることで、正圧用一方向弁の開弁期間が
減少してキャニスタへの燃料蒸気の供給量が減り、しか
も温度低下時に負圧用一方向弁が開弁するまで時間が従
来例よりも長くなることで、負圧用一方向弁の開弁期間
が減少して燃料タンクへの空気の吸入量が減って新たな
燃料の蒸発量が減ることで、燃料タンクから供給される
燃料蒸気によるキャニスタのチャージ量を減少させるこ
とができる。
【０００７】
【発明の実施の形態】以下、本発明の実施の形態を、添
付図面に示した本発明の実施例に基づいて説明する。
【０００８】図１〜図４は本発明の一実施例を示すもの
で、図１はエンジンの燃料蒸気処理系の全体構成図、図
２は経過時間に対する燃料タンクの温度および燃料タン
クの内圧の変化を示すグラフ、図３は経過時間に対する
キャニスタのチャージ量の変化を示すグラフ、図４は二
方向弁の負圧用一方向弁の開弁圧とキャニスタのチャー
ジ量との関係を示すグラフである。
【０００９】図１に示すように、車両用の燃料タンクＴ
からフィルタ１および燃料ポンプ２を介して汲み上げら
れた燃料はフィードパイプ３を介してエンジンＥの燃料
噴射弁４に供給される。燃料タンクＴの上部空間とエン
ジンＥの吸気通路５に設けたスロットル弁６の下流位置
とがチャージパイプ７およびパージパイプ８により接続
され、これらチャージパイプ７およびパージパイプ８間
に燃料蒸気をチャージおよびパージ可能なキャニスタＣ
が配置される。
【００１０】キャニスタＣは上下のフィルタ９，１０間
に吸着剤としての活性炭１１を収納したもので、燃料タ
ンクＴ側のチャージパイプ７が活性炭１１の内部に開口
するとともに、エンジンＥ側のパージパイプ８が上部フ
ィルタ９の上部空間に開口し、下部フィルタ１０の下部
空間が大気開放端１２を介して大気に開放する。
【００１１】燃料タンクＴとキャニスタＣとを接続する
チャージパイプ７には二方向弁Ｖが配置される。二方向
弁Ｖは、燃料タンクＴの内圧が大気圧よりも所定値を越
えて増加した場合に、ダイヤフラム１３に支持された正
圧用一方向弁１４がスプリング１５の弾発力に抗して開
弁し、燃料タンクＴをキャニスタＣに連通させる。また
燃料タンクＴの内圧がキャニスタＣの内圧よりも所定値
を越えて減少した場合に、負圧用一方向弁１６がスプリ
ング１７の弾発力に抗して開弁し、キャニスタＣを燃料
タンクＴに連通させる。尚、後述するパージ時にキャニ
スタＣ側が負圧になる場合があるが、その場合には二方
向弁Ｖの正圧用一方向弁１４および負圧用一方向弁１６
は共に閉弁状態に保持される。
【００１２】キャニスタＣとエンジンＥの吸気通路５と
を接続するパージパイプ８には、電磁弁よりなるパージ
制御弁１８が設けられる。パージ制御弁１８が開弁する
とキャニスタＣと吸気通路５とが連通し、パージ制御弁
１８が閉弁するとキャニスタＣと吸気通路５との連通が
遮断される。
【００１３】エンジンＥの停止中には、パージ制御弁１
８は閉弁状態に保持されている。この状態で燃料タンク
Ｔの温度が上昇し、燃料の蒸発によって燃料タンクＴの
内圧が増加すると、二方向弁Ｖの正圧用一方向弁１４が
開弁して燃料タンクＴ内の燃料蒸気および空気がチャー
ジ通路７を介してキャニスタＣに流入し、そこで燃料蒸
気が活性炭１１に吸着されて外部に洩れることが防止さ
れる。
【００１４】エンジンＥの始動後に所定時間が経過して
運転状態が安定すると、パージパイプ８に設けたパージ
制御弁１８が開弁してキャニスタＣとエンジンＥの吸気
通路５とが連通するため、吸気通路５に発生する負圧が
キャニスタＣを介して大気開放端１２に伝達される。そ
の結果、大気開放端１２からキャニスタＣに空気が導入
され、キャニスタＣの活性炭１１に吸着されていた燃料
蒸気がパージされ、前記空気と共に吸気通路５に供給さ
れる。
【００１５】温度低下により燃料タンクＴの内部空間が
負圧になると、二方向弁Ｖの負圧用一方向弁１６が開弁
し、大気開放端１２から吸入された空気がキャニスタＣ
およびチャージパイプ７を通って燃料タンクＴに供給さ
れ、過剰な負圧による燃料タンクＴの変形が防止され
る。
【００１６】本実施例の二方向弁Ｖは、その正圧用一方
向弁１４の開弁圧が大気圧よりも僅かに高い０．３ｋＰ
ａに設定されており、その負圧用一方向弁１６の開弁圧
が大気圧よりもかなり低い−１０ｋＰａに設定されてい
る。
【００１７】図２には、エンジンＥを停止させた状態で
車両を放置し、その間に鎖線で示すような温度変化を与
えた場合に、燃料タンクＴの内圧がどのように変化する
かを示すものである。ここで実線は本実施例の二方向弁
Ｖを備えた燃料タンクＴの特性を示し、破線は従来例の
二方向弁Ｖを備えた燃料タンクＴの特性を示している。
この特性の主たる差異は、破線で示す従来例の二方向弁
Ｖの負圧用一方向弁１６の開弁圧が−１．３ｋＰａと比
較的に高いのに対し、実線で示す実施例の二方向弁Ｖの
負圧用一方向弁１６の開弁圧が−１０ｋＰａと大幅に低
くなっていることが原因である。
【００１８】従って、鎖線で示すように温度変化が２４
時間周期で１８℃〜４１℃間を上下したとき、従来例は
燃料タンクＴの内圧の変化幅が小さく、実施例は燃料タ
ンクＴの内圧の変化幅が大きくなっている。具体的に
は、従来例は燃料タンクＴの内圧が温度の上昇と共に−
１．３ｋＰａから１．８ｋＰａまで増加すると正圧用一
方向弁１４が開弁して燃料タンクＴ内の燃料蒸気がキャ
ニスタＣに排出されることにより、燃料タンクＴの内圧
は略一定の１．８ｋＰａに維持される。温度の低下によ
り正圧用一方向弁１４が閉弁すると、燃料タンクＴの内
圧が減少し、−１．３ｋＰａにおいて負圧用一方向弁１
６が開弁する。その結果、キャニスタＣの開放端１２か
ら吸入された空気が燃料タンクＴに供給され、燃料タン
クＴの内圧は−１．３ｋＰａに維持される。上記サイク
ルが２４時間周期の温度変化に応じて繰り返される。
【００１９】図３には、図２に対応するキャニスタＣの
燃料蒸気チャージ量が示される。破線は従来例の二方向
弁Ｖを備えた燃料タンクＴに対応する特性であり、正圧
用一方向弁１４が開弁して燃料タンクＴ内の燃料蒸気が
キャニスタＣに排出される間に該キャニスタＣがチャー
ジされ、翌日のサイクルにおける正圧用一方向弁１４の
開弁時にはチャージ量が更に加算される。それに対し
て、実線で示す実施例の二方向弁Ｖを備えた燃料タンク
Ｔに対応する特性では、キャニスタＣのチャージ量が従
来例に比べて約３０％少なくなっている。これは実施例
の二方向弁Ｖの負圧用一方向弁１６の開弁圧を低く設定
したことによる効果であり、この効果が得られる理由を
以下に説明する。
【００２０】図２において、実施例の二方向弁Ｖの負圧
用一方向弁１６の開弁圧が−１０ｋＰａと低く設定され
ているため、温度上昇により燃料タンクＴの内圧が正圧
用一方向弁１４の開弁圧である０．３ｋＰａに達するま
でに時間が掛かる。その結果、正圧用一方向弁１４が開
弁している時間が従来例よりも短くなり、その分だけキ
ャニスタＣのチャージ量が従来例よりも小さくなる。更
に二方向弁Ｖの負圧用一方向弁１６の開弁圧が−１０ｋ
Ｐａと低く設定されているため、温度低下時に負圧用一
方向弁１６が開弁するのに時間が掛かる。その結果、負
圧用一方向弁１６が開弁している時間が従来例よりも小
さくなり、その分だけ大気開放端１２からキャニスタＣ
を経て燃料タンクＴに吸入される空気の量が少なくな
る。このように燃料タンクＴに吸入される空気の量が減
少すると、燃料タンクＴ内で燃料が新たに蒸発し難くな
るため、温度上昇により燃料タンクＴの内圧が０．３ｋ
Ｐａに達して正圧用一方向弁１４が開弁したとき、燃料
タンクＴからキャニスタＣにチャージされる燃料蒸気の
量が減少する。
【００２１】以上説明した二つの要因、すなわち正圧用
一方向弁１４が開弁している時間が従来例よりも短くな
るためにキャニスタＣへの燃料蒸気の供給量が減ること
と、負圧用一方向弁１６が開弁している時間が従来例よ
りも短くなるために燃料タンクＴへの空気の吸入量（つ
まり新たな燃料の蒸発量）が減ることとにより、キャニ
スタＣへの燃料のチャージ量を減少させることができ
る。
【００２２】図４には、負圧用一方向弁１６の開弁圧と
キャニスタＣのチャージ量とが種々の容量の燃料タンク
Ｔについて示される。燃料タンクＴの容量に関わらず、
負圧用一方向弁１６の開弁圧が−７ｋＰａよりも高いと
きは開弁圧の減少に伴うキャニスタＣのチャージ量の減
少率は小さいが、開弁圧が−７ｋＰａ以下であればキャ
ニスタＣのチャージ量の減少率は際立って大きくなる。
理論上は、約−５０ｋＰａにてチャージ量をゼロにする
ことも可能である。一方、無制限に開弁圧を下げてゆく
と、最終的には燃料タンクＴの強度が負圧に耐えられな
くなる。従って、負圧用一方向弁１６の開弁圧の適切な
開弁圧は−７ｋＰａを上限とし、燃料タンクＴの強度を
下限とする範囲に設定すれば良い。
【００２３】以上、本発明の実施例を詳述したが、本発
明はその要旨を逸脱しない範囲で種々の設計変更を行う
ことが可能である。
【００２４】
【発明の効果】以上のように請求項１に記載された発明
によれば、燃料タンクおよびキャニスタ間に配置した二
方向弁の負圧用一方向弁が開弁する燃料タンクの内圧を
従来よりも低い−７ｋＰａ以下の任意の点に設定したの
で、温度上昇時に負圧用一方向弁が閉弁してから正圧用
一方向弁が開弁するまで時間が従来よりも長くなること
で、正圧用一方向弁の開弁期間が減少してキャニスタへ
の燃料蒸気の供給量が減り、しかも温度低下時に負圧用
一方向弁が開弁するまで時間が従来例よりも長くなるこ
とで、負圧用一方向弁の開弁期間が減少して燃料タンク
への空気の吸入量が減って新たな燃料の蒸発量が減るこ
とで、燃料タンクから供給される燃料蒸気によるキャニ
スタのチャージ量を減少させることができる。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-way valve for positive pressure, which opens a fuel tank and a canister when the internal pressure of the fuel tank increases, and a fuel tank. The present invention relates to a fuel vapor generation suppression device for a vehicle fuel tank connected via a two-way valve having a one-way valve for negative pressure which opens when the internal pressure decreases. 2. Description of the Related Art A two-way valve in which a one-way valve for positive pressure and a one-way valve for negative pressure are combined in a reverse direction is disposed between a fuel tank of an automobile and a canister. When the internal pressure rises and rises, the one-way valve for positive pressure opens to charge the fuel vapor in the fuel tank to the canister, thereby preventing the release of the fuel vapor to the atmosphere. Further, when the temperature of the fuel tank decreases and the internal pressure decreases, the one-way valve for negative pressure opens and the atmosphere is sucked into the fuel tank through the canister, thereby preventing the fuel tank from being deformed by the negative pressure. In the conventional two-way valve, the opening pressure of the one-way valve for positive pressure is set to a pressure slightly higher than the atmospheric pressure (for example, about 2 kPa),
The opening pressure of the one-way valve for negative pressure was set to a pressure slightly lower than the atmospheric pressure (for example, about -1.3 kPa). [0003] The fuel vapor charged in the canister is purged into the intake system during operation of the engine. However, when the engine is left unused for several days without using an automobile, Since the fuel vapor charged to the canister is not purged, the charge amount of the canister is accumulated every time the one-way valve for positive pressure is opened, and eventually the canister becomes fully charged and it is not possible to charge any more fuel vapor There is. The present invention has been made in view of the above circumstances, and has as its object to minimize the amount of charge of a canister when an automobile is left for a long period of time without operating an engine. According to the first aspect of the present invention, a fuel tank and a canister are opened when the internal pressure of the fuel tank increases. The fuel vapor generation suppression device for a vehicle fuel tank is connected via a two-way valve having a one-way valve for positive pressure to perform pressure and a one-way valve for negative pressure to open when the internal pressure of the fuel tank decreases. A fuel vapor generation suppression device for a vehicle fuel tank is proposed, wherein the internal pressure of the fuel tank at which the pressure one-way valve opens is set at an arbitrary point of -7 kPa or less. According to the above configuration, the internal pressure of the fuel tank at which the one-way valve for negative pressure of the two-way valve disposed between the fuel tank and the canister opens is set to an arbitrary point of -7 kPa or lower, which is lower than the conventional one. Because the time from when the one-way valve for negative pressure closes when the temperature rises to when the one-way valve for positive pressure opens becomes longer than before, the opening period of the one-way valve for positive pressure decreases and the canister is opened. The amount of fuel vapor supplied decreases, and the time required for the one-way valve for negative pressure to open when the temperature drops is longer than in the conventional example. By reducing the amount of air suctioned and the amount of new fuel evaporated, the amount of charge of the canister by the fuel vapor supplied from the fuel tank can be reduced. An embodiment of the present invention will be described below based on an embodiment of the present invention shown in the accompanying drawings. FIGS. 1 to 4 show an embodiment of the present invention. FIG. 1 is a diagram showing the overall structure of a fuel vapor processing system of an engine, and FIG. 2 is a graph showing the relationship between the temperature of the fuel tank and the internal pressure of the fuel tank with respect to elapsed time. FIG. 3 is a graph showing a change in the amount of charge of the canister with respect to elapsed time, and FIG. 4 is a graph showing a relationship between the valve opening pressure of the one-way valve for negative pressure of the two-way valve and the amount of charge of the canister. . As shown in FIG. 1, a fuel tank T for a vehicle is used.
The fuel pumped through the filter 1 and the fuel pump 2 is supplied to the fuel injection valve 4 of the engine E through the feed pipe 3. The upper space of the fuel tank T and a position downstream of the throttle valve 6 provided in the intake passage 5 of the engine E are connected by a charge pipe 7 and a purge pipe 8, and fuel vapor is charged and charged between the charge pipe 7 and the purge pipe 8. Purgeable canister C
Is arranged. The canister C contains activated carbon 11 as an adsorbent between upper and lower filters 9 and 10. The charge pipe 7 on the fuel tank T side opens into the activated carbon 11 and the purge pipe on the engine E side. 8 opens into the upper space of the upper filter 9, and the lower space of the lower filter 10 opens to the atmosphere through the open-to-atmosphere end 12. A two-way valve V is disposed on the charge pipe 7 connecting the fuel tank T and the canister C. When the internal pressure of the fuel tank T exceeds the atmospheric pressure by more than a predetermined value, the two-way valve V opens the positive pressure one-way valve 14 supported by the diaphragm 13 against the elastic force of the spring 15. The valve is opened to communicate the fuel tank T with the canister C. Further, when the internal pressure of the fuel tank T decreases by more than a predetermined value from the internal pressure of the canister C, the one-way valve 16 for negative pressure opens against the resilience of the spring 17, and the canister C is opened. To communicate with In some cases, the pressure of the canister C becomes negative at the time of purging, which will be described later. In such a case, the positive pressure one-way valve 14 and the negative pressure one-way valve 16 of the two-way valve V are used.
Are both kept closed. The purge pipe 8 connecting the canister C and the intake passage 5 of the engine E is provided with a purge control valve 18 composed of an electromagnetic valve. When the purge control valve 18 opens, the canister C communicates with the intake passage 5, and when the purge control valve 18 closes, the communication between the canister C and the intake passage 5 is cut off. While the engine E is stopped, the purge control valve 1
Numeral 8 is kept in a valve closed state. In this state, when the temperature of the fuel tank T rises and the internal pressure of the fuel tank T increases due to evaporation of the fuel, the one-way valve 14 for positive pressure of the two-way valve V opens to open the fuel vapor and air in the fuel tank T. Flows into the canister C through the charge passage 7, where the fuel vapor is prevented from being adsorbed by the activated carbon 11 and leaking to the outside. When a predetermined time elapses after the start of the engine E and the operating state is stabilized, the purge control valve 18 provided in the purge pipe 8 is opened, and the canister C communicates with the intake passage 5 of the engine E. The negative pressure generated in the intake passage 5 is transmitted to the atmosphere open end 12 via the canister C. As a result, air is introduced into the canister C from the open-to-atmosphere end 12, the fuel vapor adsorbed on the activated carbon 11 of the canister C is purged, and supplied to the intake passage 5 together with the air. When the internal space of the fuel tank T becomes a negative pressure due to the temperature drop, the negative pressure one-way valve 16 of the two-way valve V opens, and the air sucked from the atmosphere open end 12 is discharged to the canister C.
Then, the fuel is supplied to the fuel tank T through the charge pipe 7, and the deformation of the fuel tank T due to an excessive negative pressure is prevented. In the two-way valve V of this embodiment, the opening pressure of the one-way valve 14 for positive pressure is 0.3 kP slightly higher than the atmospheric pressure.
The opening pressure of the one-way valve 16 for negative pressure is set to -10 kPa, which is considerably lower than the atmospheric pressure. FIG. 2 shows how the internal pressure of the fuel tank T changes when the vehicle is left in a state where the engine E is stopped and a temperature change as indicated by a chain line is given during that time. Things. Here, the solid line shows the characteristics of the fuel tank T provided with the two-way valve V of the present embodiment, and the broken line shows the characteristics of the fuel tank T provided with the conventional two-way valve V.
The main difference of this characteristic is that the opening pressure of the negative one-way valve 16 of the conventional two-way valve V of the conventional example shown by the broken line is relatively high at -1.3 kPa, whereas the two-way valve of the embodiment shown by the solid line is relatively high. This is because the valve opening pressure of the one-way valve 16 for negative pressure of the valve V is greatly reduced to -10 kPa. Therefore, as shown by the dashed line, the temperature change is 24
When the temperature fluctuates between 18 ° C. and 41 ° C. in a time cycle, the variation in the internal pressure of the fuel tank T is small in the conventional example, and the variation in the internal pressure of the fuel tank T is large in the embodiment. Specifically, in the conventional example, the internal pressure of the fuel tank T increases as the temperature increases.
When the pressure increases from 1.3 kPa to 1.8 kPa, the one-way valve 14 for positive pressure is opened and the fuel vapor in the fuel tank T is discharged to the canister C, so that the internal pressure of the fuel tank T is substantially constant at 1.8 kPa. Is maintained. When the positive pressure one-way valve 14 closes due to a decrease in temperature, the internal pressure of the fuel tank T decreases, and at -1.3 kPa, the negative pressure one-way valve 1
6 opens. As a result, the air sucked from the open end 12 of the canister C is supplied to the fuel tank T, and the internal pressure of the fuel tank T is maintained at -1.3 kPa. The above cycle is repeated according to a temperature change in a 24-hour cycle. FIG. 3 shows the fuel vapor charge amount of the canister C corresponding to FIG. The dashed line is a characteristic corresponding to the fuel tank T provided with the conventional two-way valve V. The one-way valve 14 for positive pressure opens while the fuel vapor in the fuel tank T is discharged to the canister C. When the canister C is charged and the one-way valve 14 for positive pressure is opened in the next day's cycle, the charge amount is further added. On the other hand, in the characteristic corresponding to the fuel tank T having the two-way valve V of the embodiment shown by the solid line, the charge amount of the canister C is reduced by about 30% as compared with the conventional example. This is an effect of setting the valve opening pressure of the one-way valve 16 for negative pressure of the two-way valve V of the embodiment low, and the reason why this effect is obtained will be described below. In FIG. 2, since the opening pressure of the one-way valve 16 for negative pressure of the two-way valve V of the embodiment is set to be as low as -10 kPa, the internal pressure of the fuel tank T is reduced by the temperature rise. It takes time to reach 0.3 kPa, which is the valve opening pressure of No. 14. As a result, the time during which the one-way valve for positive pressure 14 is open is shorter than in the conventional example, and the charge amount of the canister C is correspondingly smaller than in the conventional example. Further, the opening pressure of the one-way valve 16 for negative pressure of the two-way valve V is -10 k.
Since the pressure is set to be as low as Pa, it takes time for the one-way valve for negative pressure 16 to open when the temperature drops. As a result, the time during which the negative pressure one-way valve 16 is open is shorter than in the conventional example, and the canister C
, The amount of air drawn into the fuel tank T decreases. When the amount of air sucked into the fuel tank T decreases in this way, it becomes difficult for the fuel to newly evaporate in the fuel tank T, and the internal pressure of the fuel tank T becomes 0.3 k
When the pressure reaches Pa and the one-way valve for positive pressure 14 opens, the amount of fuel vapor charged from the fuel tank T to the canister C decreases. The two factors explained above, that is, the time during which the one-way valve 14 for positive pressure is open are shorter than in the conventional example, so that the supply amount of fuel vapor to the canister C is reduced. Since the time during which the directional valve 16 is open is shorter than in the conventional example, the amount of air sucked into the fuel tank T (that is, the amount of new fuel vaporized) is reduced, thereby charging the fuel to the canister C. The amount can be reduced. FIG. 4 shows the opening pressure of the one-way valve 16 for negative pressure and the amount of charge of the canister C for the fuel tanks T of various capacities. Regardless of the capacity of the fuel tank T,
When the valve opening pressure of the negative pressure one-way valve 16 is higher than -7 kPa, the rate of decrease in the charge amount of the canister C with the decrease in valve opening pressure is small. The rate of decrease of the charge amount becomes remarkably large.
Theoretically, it is possible to make the charge amount zero at about -50 kPa. On the other hand, if the valve opening pressure is reduced without limitation, the strength of the fuel tank T eventually cannot withstand the negative pressure. Therefore, an appropriate opening pressure of the one-way valve 16 for negative pressure may be set to a range in which the upper limit is -7 kPa and the strength of the fuel tank T is the lower limit. Although the embodiments of the present invention have been described in detail, various design changes can be made in the present invention without departing from the gist thereof. As described above, according to the first aspect of the present invention, the internal pressure of the fuel tank in which the one-way valve for negative pressure of the two-way valve disposed between the fuel tank and the canister opens. Since it was set to an arbitrary point of -7 kPa or less lower than before, the time from when the one-way valve for negative pressure was closed at the time of temperature rise to when the one-way valve for positive pressure was opened was longer than before, The opening time of the one-way valve for positive pressure decreases, the amount of fuel vapor supplied to the canister decreases, and the time required for the one-way valve for negative pressure to open when the temperature drops is longer than in the conventional example. The opening time of the one-way pressure valve is reduced, the amount of air taken into the fuel tank is reduced, and the amount of new fuel evaporated is reduced, thereby reducing the amount of charge of the canister by fuel vapor supplied from the fuel tank. be able to.
【図面の簡単な説明】
【図１】エンジンの燃料蒸気処理系の全体構成図
【図２】経過時間に対する燃料タンクの温度および燃料
タンクの内圧の変化を示すグラフ
【図３】経過時間に対するキャニスタのチャージ量の変
化を示すグラフ
【図４】二方向弁の負圧用一方向弁の開弁圧とキャニス
タのチャージ量との関係を示すグラフ
【符号の説明】
Ｃ キャニスタ
Ｔ 燃料タンク
Ｖ 二方向弁
１４ 正圧用一方向弁
１６ 負圧用一方向弁BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall configuration diagram of a fuel vapor processing system of an engine. FIG. 2 is a graph showing changes in the temperature of a fuel tank and the internal pressure of the fuel tank with respect to elapsed time. FIG. FIG. 4 is a graph showing a relationship between a valve opening pressure of a one-way valve for negative pressure of a two-way valve and a charge amount of a canister. [Description of symbols] C canister T fuel tank V two-way valve 14 One-way valve for positive pressure 16 One-way valve for negative pressure
フロントページの続き (72)発明者 北村 寛 埼玉県和光市中央１丁目４番１号 株式会 社本田技術研究所内 (72)発明者 北本 昌一 埼玉県和光市中央１丁目４番１号 株式会 社本田技術研究所内 (72)発明者 本多 剛志 埼玉県和光市中央１丁目４番１号 株式会 社本田技術研究所内 (72)発明者 佐藤 大介 埼玉県和光市中央１丁目４番１号 株式会 社本田技術研究所内 Ｆターム(参考） 3D038 CA25 CC02 CC05 3G044 BA20 GA03 GA06 GA23 Continuation of front page (72) Inventor Hiroshi Kitamura 1-4-1 Chuo, Wako-shi, Saitama Stock Association Inside the Honda Research Laboratory (72) Inventor Shoichi Kitamoto 1-4-1 Chuo, Wako-shi, Saitama Stock Association Inside the Honda Research Laboratory (72) Inventor Takeshi Honda 1-4-1 Chuo, Wako-shi, Saitama Stock Association Inside the Honda Research Laboratory (72) Inventor Daisuke Sato 1-4-1 Chuo, Wako-shi, Saitama Stock Association Inside the Honda Research Laboratory F term (reference) 3D038 CA25 CC02 CC05 3G044 BA20 GA03 GA06 GA23
Claims (1)
を、燃料タンク（Ｔ）の内圧が増加したときに開弁する
正圧用一方向弁（１４）と、燃料タンク（Ｔ）の内圧が
減少したときに開弁する負圧用一方向弁（１６）とを有
する二方向弁（Ｖ）を介して接続した車両用燃料タンク
の燃料蒸気発生抑制装置において、 前記負圧用一方向弁（１６）が開弁する燃料タンク
（Ｔ）の内圧を−７ｋＰａ以下の任意の点に設定したこ
とを特徴とする車両用燃料タンクの燃料蒸気発生抑制装
置。Claims: 1. A positive pressure one-way valve (14) that opens a fuel tank (T) and a canister (C) when the internal pressure of the fuel tank (T) increases, and a fuel tank. A fuel vapor generation suppressing device for a vehicle fuel tank connected via a two-way valve (V) having a one-way valve for negative pressure (16) that opens when the internal pressure of the tank (T) decreases. A fuel vapor generation suppression device for a vehicle fuel tank, wherein the internal pressure of the fuel tank (T) at which the pressure one-way valve (16) is opened is set at an arbitrary point of -7 kPa or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002132573A JP2003080960A (en) | 2001-07-03 | 2002-05-08 | Fuel vapor generation restricting device for fuel tank in vehicle |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001-201665 | 2001-07-03 | ||
| JP2001201665 | 2001-07-03 | ||
| JP2002132573A JP2003080960A (en) | 2001-07-03 | 2002-05-08 | Fuel vapor generation restricting device for fuel tank in vehicle |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2003080960A true JP2003080960A (en) | 2003-03-19 |
Family
ID=26618028
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2002132573A Pending JP2003080960A (en) | 2001-07-03 | 2002-05-08 | Fuel vapor generation restricting device for fuel tank in vehicle |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2003080960A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10767600B2 (en) | 2016-12-22 | 2020-09-08 | Polaris Industries Inc. | Evaporative emissions control for a vehicle |
| DE102019134438A1 (en) * | 2019-12-16 | 2021-06-17 | Bayerische Motoren Werke Aktiengesellschaft | Operating medium container system for arrangement in a motor vehicle and motor vehicle |
-
2002
- 2002-05-08 JP JP2002132573A patent/JP2003080960A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10767600B2 (en) | 2016-12-22 | 2020-09-08 | Polaris Industries Inc. | Evaporative emissions control for a vehicle |
| US11585300B2 (en) | 2016-12-22 | 2023-02-21 | Polaris Industries Inc. | Evaporative emissions control for a vehicle |
| DE102019134438A1 (en) * | 2019-12-16 | 2021-06-17 | Bayerische Motoren Werke Aktiengesellschaft | Operating medium container system for arrangement in a motor vehicle and motor vehicle |
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