JP3444196B2

JP3444196B2 - Abnormality detection device for fuel gas emission suppression device

Info

Publication number: JP3444196B2
Application number: JP15162698A
Authority: JP
Inventors: 中山　　昌昭; 向井　　弥寿夫; 真三輪
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 1997-07-11
Filing date: 1998-06-01
Publication date: 2003-09-08
Anticipated expiration: 2018-06-01
Also published as: JPH1182188A

Description

Detailed Description of the Invention

【０００１】[0001]

【発明の属する技術分野】本発明は、燃料タンク内で発
生する燃料ガス（蒸発燃料）が大気中に排出されるのを
防止するための燃料ガス排出抑止装置に係り、同装置用
の異常検出装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel gas discharge suppressing device for preventing fuel gas (evaporated fuel) generated in a fuel tank from being discharged into the atmosphere, and an abnormality detecting device for the device. It relates to the device.

【０００２】[0002]

【従来の技術】従来より自動車等においては、燃料タン
ク内で発生する燃料ガスが大気中に排出されるのを防止
するために、燃料ガス排出抑止装置の装着が義務付けら
れるなどの規制がある。燃料ガス排出抑止装置は、燃料
タンクと機関の吸気管とを連通するパージ通路の途中に
設けられたキャニスタに燃料ガスを随時吸着させ、内燃
機関の運転状態に応じてパージ制御弁を開閉することに
より、吸着した燃料ガスを吸気管内に適宜放出させる。
そして、吸気管に放出した燃料ガスを燃料混合気中に混
入させることで燃料の外部への排出を抑止する装置であ
る。2. Description of the Related Art Conventionally, in automobiles and the like, in order to prevent the fuel gas generated in a fuel tank from being discharged into the atmosphere, there is a regulation that a fuel gas discharge suppressing device is required to be mounted. The fuel gas emission control device is to adsorb fuel gas to a canister provided in the middle of a purge passage that connects a fuel tank and an intake pipe of the engine, and to open and close a purge control valve according to the operating state of the internal combustion engine. Thus, the adsorbed fuel gas is appropriately released into the intake pipe.
The fuel gas discharged to the intake pipe is mixed into the fuel mixture to suppress the discharge of fuel to the outside.

【０００３】こうした燃料ガス排出抑止装置では通常、
キャニスタと吸気管との間をゴムホースで連通するなど
してパージ通路が形成されており、このゴムホースが損
傷したり脱落したりすると、燃料ガスが外部（大気中）
に漏れ出てしまう。そこで、このような燃料ガスの漏れ
出し（リーク）を監視する装置として、例えば特開平５
−１２５９９７号公報の「燃料蒸散防止装置用異常検出
装置」では、燃料タンクに圧力センサを取り付け、その
センサ検出値に応じて燃料ガスのリーク異常を判定する
ようにしていた。詳細には、燃料タンクから機関の吸気
管までを密閉化し、その密閉区間を大気圧付近や所定の
負圧レベルに圧力調整している。そして、その時の密閉
区間内の燃料ガス発生に伴う圧力変化状態から、燃料漏
れや通路閉塞などの異常を検出していた。In such a fuel gas emission control device, normally,
A purge hose is formed by connecting a rubber hose between the canister and the intake pipe. If this rubber hose is damaged or drops off, the fuel gas will be discharged outside (in the atmosphere).
Will leak out. Therefore, as an apparatus for monitoring such a leak of fuel gas, for example, Japanese Patent Laid-Open No. Hei 5
In the "abnormality detection device for fuel evaporation prevention device" of Japanese Patent No. 125997, a pressure sensor is attached to a fuel tank, and a fuel gas leak abnormality is determined according to the sensor detection value. More specifically, the fuel tank to the intake pipe of the engine are hermetically sealed, and the hermetically sealed section is pressure-controlled near atmospheric pressure or at a predetermined negative pressure level. Then, an abnormality such as fuel leakage or passage blockage is detected from the pressure change state due to the generation of fuel gas in the closed section at that time.

【０００４】[0004]

【発明が解決しようとする課題】ところが、上記従来装
置において、密閉区間内を所定の負圧レベルに調整する
と、その圧力調整直後に燃料ガスが急激に発生する。そ
のため、パージ通路を形成するゴムホース等が損傷して
おらず燃料リークが無くとも、圧力状態の変化量が比較
的大きくなる。また一方、ゴムボースに微小径の孔（例
えばφ０．５ｍｍ程度の孔）が開いている場合には、燃
料ガスのリーク量が比較的少ないため、そのリークに起
因する圧力変化量は比較的少ないものとなる。However, in the above-mentioned conventional apparatus, when the closed section is adjusted to a predetermined negative pressure level, the fuel gas is rapidly generated immediately after the pressure adjustment. Therefore, even if the rubber hose or the like forming the purge passage is not damaged and there is no fuel leak, the change amount of the pressure state becomes relatively large. On the other hand, when a small diameter hole (for example, a hole having a diameter of about 0.5 mm) is opened in the rubber bose, the amount of fuel gas leakage is relatively small, and therefore the amount of pressure change due to the leakage is relatively small. Becomes

【０００５】こうした理由から、密閉区間内で所定の負
圧レベルから正圧側への圧力変化量から異常の有無を検
出する従来装置では、圧力調整直後の燃料ガスの多量発
生によって圧力状態の変化が生じる場合や、微細孔が開
いている時に圧力変化量が比較的小さい場合において、
正確な異常検出が行えないという問題があった。For this reason, in the conventional device that detects the presence or absence of abnormality from the pressure change amount from the predetermined negative pressure level to the positive pressure side in the closed section, the pressure state changes due to the large amount of fuel gas generated immediately after the pressure adjustment. When it occurs, or when the amount of pressure change is relatively small when the fine holes are open,
There is a problem that accurate abnormality detection cannot be performed.

【０００６】本発明は、上記問題に着目してなされたも
のであって、その目的とするところは、微細孔による燃
料ガスの漏れ時にもその異常を正確に検出することがで
きる燃料ガス排出抑止装置用の異常検出装置を提供する
ことである。The present invention has been made in view of the above problems, and an object of the present invention is to suppress the fuel gas emission capable of accurately detecting the abnormality even when the fuel gas leaks through the fine holes. An abnormality detection device for a device is provided.

【０００７】[0007]

【課題を解決するための手段】上記目的を達成するため
に本発明ではその前提として、燃料タンクにて発生する
燃料ガスをキャニスタに蓄え、該キャニスタに蓄えられ
た燃料ガスを空気と共にパージ配管を介して機関の吸気
通路に放出するようにした燃料ガス排出抑止装置に適用
され、前記燃料タンクから機関の吸気通路までを密閉化
すると共に、該密閉区間内の圧力を所定の負圧レベルに
調整する圧力調整手段と、該圧力調整手段による圧力調
整後、その際の圧力変化から前記燃料ガス排出抑止装置
の異常を検出する異常検出手段とを備える。In order to achieve the above object, the present invention is based on the premise that fuel gas generated in a fuel tank is stored in a canister, and the fuel gas stored in the canister is purged together with air through a purge pipe. It is applied to a fuel gas emission restraint device that discharges to the intake passage of an engine through a valve, seals from the fuel tank to the intake passage of the engine, and adjusts the pressure in the closed section to a predetermined negative pressure level. Pressure adjusting means and an abnormality detecting means for detecting an abnormality of the fuel gas emission suppressing device from the pressure change at that time after the pressure adjustment by the pressure adjusting means.

【０００８】そして請求項１に記載の発明では、前記圧
力調整手段による負圧レベルでの圧力調整直後に、その
際に調整される負圧レベルを所定時間だけその付近で保
持する負圧保持手段と、前記負圧保持手段による所定時
間の負圧保持後、前記異常検出のための圧力状態の検出
を開始する異常検出開始許可手段とを備える。According to the first aspect of the invention, immediately after the negative pressure level is adjusted by the pressure adjusting means, the negative pressure level adjusted at that time is maintained for a predetermined time in the vicinity thereof. And an abnormality detection start permitting means for starting the detection of the pressure state for the abnormality detection after the negative pressure holding means holds the negative pressure for a predetermined time.

【０００９】要するに、燃料タンクから機関の吸気通路
までの密閉区間を負圧レベルに調整すると、負圧調整の
直後には急激に燃料ガス（蒸発燃料）が発生し、この燃
料ガスの発生の度合いは時間の経過に従い次第に緩やか
になる。この場合、負圧調整の直後における圧力変化状
態から異常の有無を判定する従来装置では、圧力調整直
後の燃料ガスの多量発生によって圧力状態の変化が生じ
る場合や、微細孔が開いている時に圧力変化量が比較的
小さい場合において、正確な異常検出が行えなかった。
これに対し本発明の構成では、急激な燃料ガスの発生が
収まってから異常判定が実施されることになるため、予
期せぬ燃料ガスの発生により不用意な圧力変化が生じる
ことがなく、圧力状態の変化から精度良くリーク判定が
実施できる。その結果、微細孔による燃料ガスの漏れ時
にもその異常を正確に検出することができるようにな
る。In short, when the closed section from the fuel tank to the intake passage of the engine is adjusted to a negative pressure level, fuel gas (evaporated fuel) is rapidly generated immediately after the negative pressure adjustment, and the degree of generation of this fuel gas Gradually becomes gentler over time. In this case, in the conventional device that determines the presence or absence of abnormality from the pressure change state immediately after the negative pressure adjustment, the pressure state changes when a large amount of fuel gas is generated immediately after the pressure adjustment or when the fine holes are open. Accurate abnormality detection could not be performed when the amount of change was relatively small.
On the other hand, in the configuration of the present invention, since the abnormality determination is performed after the sudden generation of the fuel gas is stopped, the unexpected pressure change does not occur due to the unexpected generation of the fuel gas, and Leak determination can be performed accurately from the change in state. As a result, even when the fuel gas leaks through the fine holes, the abnormality can be accurately detected.

【００１０】また、前記負圧保持手段は、前記キャニス
タと機関の吸気通路との間のパージ配管に設けられたパ
ージ制御弁の開度をデューティ制御して密閉区間内の圧
力を所定の負圧レベルに保持する。同構成によれば、密
閉区間での負圧保持が適正に実施できる。 Further, the negative pressure holding means, the pressure a predetermined negative pressure of the purge control valve opening duty control to the closed section of which is provided in the purge pipe between an intake passage of the canister and the engine Hold on to the level. According to this configuration, negative pressure can be properly maintained in the closed section.

【００１１】前記負圧保持手段は、以下の請求項２〜請
求項４に記載したように、所定の負圧レベルで保持する
時間を可変に設定するとよく、各構成によれば、燃料ガ
スの発生度合いに対応させつつ、適切な負圧保持の制御
が実現できる。The negative pressure holding means may variably set the holding time at a predetermined negative pressure level, as described in claims 2 to 4 below. Appropriate negative pressure holding control can be realized while corresponding to the degree of occurrence.

【００１２】請求項２に記載の発明では、燃料タンク内
の燃料温度に応じて所定の負圧レベルで保持する時間を
可変に設定する。具体的には、燃料温度が高くなるほ
ど、保持時間を長くするとよい。According to the second aspect of the present invention, the time period for holding at a predetermined negative pressure level is variably set according to the fuel temperature in the fuel tank. Specifically, the holding time may be increased as the fuel temperature increases.

【００１３】請求項３に記載の発明では、燃料タンクの
空間容積に係るパラメータに応じて、所定の負圧レベル
で保持する時間を可変に設定する。燃料タンクの空間容
積とは同タンク内の燃料残量に対応し、燃料残量が少な
いほど空間容積は大きいこととなる。この場合、燃料タ
ンクの空間容積が大きくなるほど、保持時間を長くする
とよい。According to the third aspect of the present invention, the time for holding at the predetermined negative pressure level is variably set according to the parameter related to the space volume of the fuel tank. The space volume of the fuel tank corresponds to the remaining amount of fuel in the same tank, and the smaller the remaining amount of fuel, the larger the space volume. In this case, the holding time may be increased as the space volume of the fuel tank increases.

【００１４】請求項４に記載の発明では、燃料性状に応
じて所定の負圧レベルで保持する時間を可変に設定す
る。具体的には、ガソリン燃料のリード蒸気圧（ＲＶ
Ｐ：ReidVapor Pressure ）が大きくなるほど、保持時
間を長くするとよい。According to the fourth aspect of the invention, the time for holding at a predetermined negative pressure level is variably set according to the fuel property. Specifically, the Reid vapor pressure of gasoline fuel (RV
As the P: Reid Vapor Pressure) increases, the holding time may be increased.

【００１５】またここで、リークの有無やリーク原因を
容易に検出するには、請求項５のように構成するとよ
い。すなわち、請求項５に記載の発明では、前記燃料タ
ンクから機関の吸気通路までの密閉化の際に、前記負圧
レベルでの圧力調整に加えてその負圧レベルとは異なる
他の圧力レベルで圧力調整を行い、前者の圧力調整時の
圧力変化状態と、後者の圧力調整時の圧力変化状態とを
比較し、その比較結果から前記燃料ガス排出抑止装置の
異常を検出するようにしている。Further, in order to easily detect the presence / absence of the leak and the cause of the leak, it is preferable to configure as in claim 5 . That is, in the invention described in claim 5 , when sealing from the fuel tank to the intake passage of the engine, in addition to the pressure adjustment at the negative pressure level, at another pressure level different from the negative pressure level. The pressure is adjusted, the former pressure change state at the time of pressure adjustment and the latter pressure change state at the time of pressure adjustment are compared, and the abnormality of the fuel gas emission suppressing device is detected from the comparison result.

【００１６】[0016]

【発明の実施の形態】以下、この発明を燃料噴射制御シ
ステムに具体化した一実施の形態を図面に従って説明す
る。本実施の形態において、車載されたガソリンエンジ
ン（内燃機関）には燃料ガス排出抑止装置が装着されて
おり、この燃料ガス排出抑止装置のキャニスタには燃料
タンクで発生した燃料ガスが一旦吸着され、その吸着燃
料はパージ通路等を介してエンジン吸気系に放出され
る。また、本制御システムでは、燃料噴射制御や燃料ガ
スのパージ制御等を司る電子制御装置（以下、ＥＣＵと
いう）が装備されている。BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is embodied in a fuel injection control system will be described below with reference to the drawings. In the present embodiment, a vehicle-mounted gasoline engine (internal combustion engine) is equipped with a fuel gas emission suppression device, and the canister of this fuel gas emission suppression device temporarily adsorbs the fuel gas generated in the fuel tank, The adsorbed fuel is released to the engine intake system via the purge passage or the like. In addition, the control system is equipped with an electronic control unit (hereinafter referred to as an ECU) that controls fuel injection control, fuel gas purge control, and the like.

【００１７】図１は、本実施の形態における燃料噴射制
御システムの概要を示す構成図である。同図に示される
ように、エンジン１には、吸気管２と排気管３とが接続
されている。吸気管２の上流には、空気を濾過するエア
クリーナ４が配設されており、このエアクリーナ４を介
して空気が吸気管２に吸入される。また、吸気管２内に
は、アクセルペダル６に連動して開閉動作するスロット
ル弁５が配設されている。上記吸入された空気は、この
スロットル弁５並びに吸気弁７を介してピストン１０上
部の燃焼室８に供給される。そして、この燃焼室８で燃
焼された後に排出される排ガスが排気弁９を介して排気
管３に排出される。FIG. 1 is a configuration diagram showing an outline of a fuel injection control system in the present embodiment. As shown in the figure, an intake pipe 2 and an exhaust pipe 3 are connected to the engine 1. An air cleaner 4 for filtering air is arranged upstream of the intake pipe 2, and the air is sucked into the intake pipe 2 via the air cleaner 4. In addition, a throttle valve 5 that opens and closes in conjunction with an accelerator pedal 6 is provided in the intake pipe 2. The sucked air is supplied to the combustion chamber 8 above the piston 10 via the throttle valve 5 and the intake valve 7. Then, the exhaust gas discharged after being burned in the combustion chamber 8 is discharged to the exhaust pipe 3 via the exhaust valve 9.

【００１８】一方、液体燃料（ガソリン）が収納された
燃料タンク１２には燃料ポンプ１３が接続されている。
燃料タンク１２内に収納されている燃料は、この燃料ポ
ンプ１３により加圧された状態で燃料噴射弁１４に給送
され、同燃料噴射弁１４の開弁動作に伴って吸気管２内
に噴射供給される。すなわち、この噴射供給された燃料
が燃焼室８内で上記吸入空気と混合され、燃焼に供され
る。On the other hand, a fuel pump 13 is connected to a fuel tank 12 containing a liquid fuel (gasoline).
The fuel stored in the fuel tank 12 is fed to the fuel injection valve 14 while being pressurized by the fuel pump 13, and is injected into the intake pipe 2 as the fuel injection valve 14 opens. Supplied. That is, the injected fuel is mixed with the intake air in the combustion chamber 8 and used for combustion.

【００１９】また、燃料タンク１２は、連通管１５を通
じてキャニスタ１６にも接続されている。なお、これら
燃料タンク１２や連通管１５も含め、以下に説明する各
部は、当該機関の燃料ガス排出抑止装置を構成する。す
なわち同燃料ガス排出抑止装置において、キャニスタ本
体１７内には、燃料タンク１２内で発生した燃料ガスを
吸着するための例えば活性炭からなる吸着体１８が収納
されている。同装置としてのこのような構成により、燃
料タンク１２内で発生した燃料ガスは、連通管１５を介
してキャニスタ本体１７に取り込まれ、同キャニスタ本
体１７内で吸着体１８に吸着されるようになる。The fuel tank 12 is also connected to a canister 16 via a communication pipe 15. Each part described below, including the fuel tank 12 and the communication pipe 15, constitutes a fuel gas emission suppressing device of the engine. That is, in the same fuel gas emission suppressing device, the canister body 17 accommodates the adsorbent 18 made of, for example, activated carbon for adsorbing the fuel gas generated in the fuel tank 12. With such a configuration as the device, the fuel gas generated in the fuel tank 12 is taken into the canister body 17 through the communication pipe 15 and is adsorbed by the adsorbent 18 in the canister body 17. .

【００２０】キャニスタ本体１７には、大気に解放され
た大気孔１９が形成されており、この大気孔１９を介し
て同キャニスタ本体１７内とその外部との間を空気が通
過する。大気孔１９には、電磁駆動式のキャニスタ閉塞
弁２０が配設されており、必要に応じてこれを閉塞する
ことができるようになっている。つまり、このキャニス
タ閉塞弁２０は、図示しないコイルの非通電（オフ）時
に大気孔１９を解放状態とし、コイルの通電（オン）時
に大気孔１９を閉塞状態とする。キャニスタ閉塞弁２０
への上記電圧印加の有無は、後述するＥＣＵ４０を通じ
て制御される。The canister body 17 is formed with an atmosphere hole 19 which is open to the atmosphere, and air passes between the inside and outside of the canister body 17 through the atmosphere hole 19. An electromagnetically driven canister shutoff valve 20 is provided in the atmosphere hole 19 and can be shut off if necessary. That is, the canister shutoff valve 20 opens the atmosphere hole 19 when the coil (not shown) is not energized (OFF) and closes the atmosphere hole 19 when the coil is energized (ON). Canister block valve 20
Whether or not the voltage is applied to the control unit is controlled through the ECU 40 described later.

【００２１】前記キャニスタ本体１７にはホース接続部
２１が形成されている。このホース接続部２１にはパー
ジ配管２２の一端が装着され、同パージ配管２２の他端
には電磁駆動式のパージ制御弁２３が接続されている。
そしてこのパージ制御弁２３が、更にパージ配管２４を
介して上記吸気管２のスロットル弁５下流側に接続され
る構造となっている。A hose connection portion 21 is formed on the canister body 17. One end of a purge pipe 22 is attached to the hose connection portion 21, and an electromagnetically driven purge control valve 23 is connected to the other end of the purge pipe 22.
The purge control valve 23 is further connected to the intake pipe 2 on the downstream side of the throttle valve 5 via a purge pipe 24.

【００２２】同燃料ガス排出抑止装置のこうした構造に
よれば、上記パージ制御弁２３が開弁されることによっ
て吸気管２とキャニスタ１６とが連通状態となり、逆に
同制御弁２３が閉弁されることによってこれら吸気管２
とキャニスタ１６とが閉塞状態となる。キャニスタ１６
にあって上記吸着体１８に吸着されている燃料ガスは、
パージ制御弁２３の開弁に基づく上記連通状態にて、吸
気管２内に発生する負圧に基づき同吸気管２内に導入さ
れるようになる。According to such a structure of the fuel gas discharge suppressing device, the intake pipe 2 and the canister 16 are brought into communication by opening the purge control valve 23, and conversely the control valve 23 is closed. These intake pipes 2
And the canister 16 are closed. Canister 16
Therefore, the fuel gas adsorbed by the adsorbent 18 is
In the communicating state based on the opening of the purge control valve 23, the negative pressure generated in the intake pipe 2 is introduced into the intake pipe 2.

【００２３】このパージ制御弁２３においては、図示し
ないコイルへの通電があると、その通電量に応じてその
開度、すなわちパージ流量が決定される。パージ制御弁
２３への通電は、デューティ制御されるパルス信号によ
って行われ、上記パージ流量も、同パルス信号のデュー
ティ比に基づき、例えば図２に示される態様で連続的に
変化する。こうしたパージ流量のデューティ制御も、後
述するＥＣＵ４０を通じて実行される。In the purge control valve 23, when the coil (not shown) is energized, the opening degree, that is, the purge flow rate is determined according to the energization amount. Energization of the purge control valve 23 is performed by a duty-controlled pulse signal, and the purge flow rate also continuously changes in the manner shown in FIG. 2, for example, based on the duty ratio of the pulse signal. Such duty control of the purge flow rate is also executed through the ECU 40 described later.

【００２４】なお、上記燃料ガス排出抑止装置におい
て、このパージ制御弁２３に接続される上記パージ配管
２２及び２４は、ゴムホースやナイロンホース等の可撓
性を有する材料で形成されている。また、上記燃料タン
ク１２とキャニスタ１６とを結ぶ連通管１５も、部分的
にはゴムホースなどによって形成されている。In the fuel gas emission restraining device, the purge pipes 22 and 24 connected to the purge control valve 23 are made of a flexible material such as a rubber hose or a nylon hose. Further, the communication pipe 15 connecting the fuel tank 12 and the canister 16 is also partially formed by a rubber hose or the like.

【００２５】また一方、上記燃料タンク１２には、同タ
ンク１２内の圧力が例えば−４０〜１５０ｈＰａの範囲
外となった場合にこれを逃がすためのリリーフ弁１２ａ
が設けられている。従って、燃料タンク１２からキャニ
スタ１６までの区間に圧力変動が生じる場合であれ、そ
の変動は常にこのリリーフ圧範囲内に抑えられるように
なる。On the other hand, in the fuel tank 12, a relief valve 12a for releasing the pressure in the fuel tank 12 when the pressure in the tank 12 falls outside the range of -40 to 150 hPa, for example.
Is provided. Therefore, even when pressure fluctuations occur in the section from the fuel tank 12 to the canister 16, the fluctuations can always be suppressed within this relief pressure range.

【００２６】燃料タンク１２には更に、同タンク１２内
の圧力を検出する圧力センサ２５が配設されている。こ
の圧力センサ２５の出力は、燃料ガス排出抑止装置内の
圧力を調圧する際のモニタ信号として利用される。な
お、この圧力センサ２５としては、上記リリーフ圧範囲
に耐え得る構造のもので足りる。また、同実施の形態の
装置では、この圧力センサ２５として、上記タンク内圧
と大気圧との差圧（相対圧）を検出する差圧センサを用
いる。The fuel tank 12 is further provided with a pressure sensor 25 for detecting the pressure in the tank 12. The output of the pressure sensor 25 is used as a monitor signal when adjusting the pressure in the fuel gas emission suppression device. The pressure sensor 25 may have a structure that can withstand the above relief pressure range. Further, in the device of the embodiment, as the pressure sensor 25, a differential pressure sensor that detects a differential pressure (relative pressure) between the tank internal pressure and the atmospheric pressure is used.

【００２７】その他、同システムにあっては、図１に併
せ示されるように、上記スロットル弁５の開度を検出す
るスロットルセンサ２６、エンジン１の回転数を検出す
る回転数センサ２７、上記吸気管２内の圧力を検出する
吸気管圧力センサ２８がそれぞれ設けられている。これ
ら各センサの出力は何れも、ＥＣＵ４０に取り込まれる
ようになる。In addition, in the system, as also shown in FIG. 1, a throttle sensor 26 for detecting the opening of the throttle valve 5, a rotation speed sensor 27 for detecting the rotation speed of the engine 1, and the intake air. An intake pipe pressure sensor 28 for detecting the pressure inside the pipe 2 is provided. The output of each of these sensors is captured by the ECU 40.

【００２８】ＥＣＵ４０は、周知のＣＰＵ４１をはじ
め、制御等の演算プログラム並びにデータが予め格納さ
れたＲＯＭ４２、制御データ等が一時格納されるＲＡＭ
４３、そして上記各種センサやアクチュエータに接続さ
れる入出力回路４４が、コモンバス４５を介して相互に
接続されて構成されている。同ＥＣＵ４０では、上記各
種センサによる検出信号に基づいて燃料噴射弁１４を駆
動し、またパージ制御弁２３やキャニスタ閉塞弁２０を
駆動して、燃料噴射制御をはじめ、キャニスタパージ制
御等を統括的に実行する。The ECU 40 includes a well-known CPU 41, a ROM 42 in which arithmetic programs for control and the like and data are stored in advance, and a RAM in which control data and the like are temporarily stored.
43, and an input / output circuit 44 connected to the various sensors and actuators are connected to each other via a common bus 45. In the ECU 40, the fuel injection valve 14 is driven based on the detection signals from the various sensors, and the purge control valve 23 and the canister closing valve 20 are driven to comprehensively control the fuel injection control, the canister purge control, and the like. Run.

【００２９】ここで、ＥＣＵ４０による本制御システム
の概要を簡単に説明する。つまり、ＥＣＵ４０は、回転
数センサ２７の出力（回転数ＮＥ）及び吸気管圧力セン
サ２８の出力（吸気圧ＰＭ）に基づいてエンジン１への
基本燃料噴射量を演算すると共に、この基本燃料噴射量
に対して空燃比補正等の各種補正を行い、最終的な燃料
噴射量を算出する。そして、エンジン１の吸気行程に同
期してその最終的な燃料噴射量により示される時間だ
け、上記燃料噴射弁１４を駆動する。Here, the outline of the present control system by the ECU 40 will be briefly described. That is, the ECU 40 calculates the basic fuel injection amount to the engine 1 based on the output of the rotation speed sensor 27 (revolution speed NE) and the output of the intake pipe pressure sensor 28 (intake pressure PM), and the basic fuel injection amount is also calculated. Then, various corrections such as air-fuel ratio correction are performed to calculate the final fuel injection amount. Then, in synchronization with the intake stroke of the engine 1, the fuel injection valve 14 is driven for the time indicated by the final fuel injection amount.

【００３０】また、ＥＣＵ４０は、例えば空燃比偏差量
に基づくフィードバック（Ｆ／Ｂ）補正係数ＦＡＦに基
づいて上記燃料ガス排出抑止装置内の燃料ガス濃度（エ
バポ濃度）を検出し、この検出した燃料ガス濃度に対応
するパージ制御弁２３の開度情報、すなわちパージ流量
を設定する。このパージ制御の実行に際しては、開度情
報を参照してパージ制御弁２３のその都度の開度を決定
し、その決定した開度に見合うようパージ制御弁２３の
開度をデューティ制御する。また、燃料ガス排出抑止装
置内の圧力（キャニスタ１６や燃料タンク１２内の圧
力）を所定に制御すべくキャニスタ閉塞弁２０の開閉を
調整する。Further, the ECU 40 detects the fuel gas concentration (evaporation concentration) in the fuel gas emission suppressing device based on, for example, a feedback (F / B) correction coefficient FAF based on the air-fuel ratio deviation amount, and the detected fuel is detected. The opening information of the purge control valve 23 corresponding to the gas concentration, that is, the purge flow rate is set. When executing the purge control, the opening degree of the purge control valve 23 is determined each time with reference to the opening degree information, and the opening degree of the purge control valve 23 is duty-controlled so as to match the determined opening degree. Further, the opening / closing of the canister shutoff valve 20 is adjusted so as to control the pressure in the fuel gas discharge suppression device (the pressure in the canister 16 and the fuel tank 12) to a predetermined value.

【００３１】さらに、ＥＣＵ４０は、以下に詳述する燃
料ガス排出抑止装置の異常検出処理を実施し、同処理に
て燃料ガス排出抑止装置における燃料ガスの漏れ出し
（リーク）などの異常発生の旨が検出された場合には、
異常警告灯２９を点灯させて異常発生を車両の搭乗者等
に警告し知らしめる。Further, the ECU 40 carries out an abnormality detection process for the fuel gas emission suppressing device, which will be described in detail below, and in the process, an error occurrence such as leakage of the fuel gas in the fuel gas emission suppressing device occurs. Is detected,
The abnormality warning light 29 is turned on to warn the passengers of the vehicle of the occurrence of the abnormality to inform them.

【００３２】次に、上記ＥＣＵ４０内のＣＰＵ４１によ
り実施される各種演算処理のうち、燃料ガス排出抑止装
置の異常検出処理について、図３〜図６のフローチャー
ト並びに図７のタイムチャートを用いて説明する。図３
〜図５の処理は、図示しないＩＧキースイッチが投入さ
れると、燃料噴射制御処理と共に、所定時間毎（例え
ば、６４ミリ秒毎）に繰り返し実行される。また、図７
のタイムチャートにおいて時刻ｔ１〜ｔ６に示す期間
は、燃料ガス排出抑止装置の燃料ガスの漏れ出しなどの
異常を検出する期間（以下には便宜上、リークチェック
期間という）に相当する。但し、図７に示すタンク内圧
ＰＴは大気圧との差圧を示している。Next, of the various calculation processes executed by the CPU 41 in the ECU 40, the abnormality detection process of the fuel gas emission suppressing device will be described with reference to the flowcharts of FIGS. 3 to 6 and the time chart of FIG. 7. . Figure 3
When the IG key switch (not shown) is turned on, the process of FIG. 5 is repeatedly executed at predetermined time intervals (for example, every 64 milliseconds) together with the fuel injection control process. Also, FIG.
In the time chart of the above, the period shown from time t1 to t6 corresponds to a period for detecting an abnormality such as leakage of the fuel gas of the fuel gas emission suppressing device (hereinafter referred to as a leak check period for convenience). However, the tank internal pressure PT shown in FIG. 7 indicates a pressure difference from the atmospheric pressure.

【００３３】処理が開始されると、ＣＰＵ４１は、先ず
図３のステップ１０１で異常検出の実施条件が成立する
か否かを判別する。具体的には、車速ＳＰ＝０であり、
且つアイドル運転中であれば異常検出の実施条件が成立
するとし、かかる条件成立時にはステップ１０２に進
む。また、条件不成立時にはそのまま本ルーチンを終了
する。つまり、本実施の形態の異常検出は、車両停止中
であり且つアイドル運転状態の時にのみ実行される。な
お、異常検出の他の実施条件として、エンジン水温が所
定温度（例えば７０℃）以上であること、外気温が所定
温度（例えば−１０℃）以上であること、車両が定速走
行中であることなどの条件を追加してもよい。When the processing is started, the CPU 41 first determines in step 101 of FIG. 3 whether or not the abnormality detection execution condition is satisfied. Specifically, the vehicle speed SP = 0,
If the condition for executing the abnormality detection is satisfied during the idle operation, the process proceeds to step 102 when the condition is satisfied. When the condition is not satisfied, this routine is finished as it is. That is, the abnormality detection of the present embodiment is executed only when the vehicle is stopped and in the idle operation state. It should be noted that, as other execution conditions of the abnormality detection, the engine water temperature is equal to or higher than a predetermined temperature (for example, 70 ° C.), the outside air temperature is equal to or higher than a predetermined temperature (for example, −10 ° C.), and the vehicle is traveling at a constant speed. Conditions such as things may be added.

【００３４】上記ステップ１０１が肯定判別されると、
ＣＰＵ４１はステップ１０２に進む。そして、ステップ
１０２〜１０５で今現在、リークチェック期間（図７の
時刻ｔ１〜ｔ６の期間）中でどの処理まで進んだかを判
別し、その判別結果に応じて各々のステップへ分岐す
る。このリークチェック期間では、第１フラグＦ１，第
２フラグＦ２，第３フラグＦ３，負圧Ｆ／ＢフラグＦｘ
の各々の操作状態から処理段階が判別される。全てのフ
ラグＦ１〜Ｆ３，Ｆｘが「０」にクリアされていれば、
すなわちステップ１０２〜１０５の全てが否定判別され
れば、ＣＰＵ４１はステップ１０６に進む。If the above step 101 is positively determined,
The CPU 41 proceeds to step 102. Then, in steps 102 to 105, it is determined which process has been progressed during the leak check period (the period from time t1 to t6 in FIG. 7), and the process branches to each step according to the determination result. In this leak check period, the first flag F1, the second flag F2, the third flag F3, the negative pressure F / B flag Fx.
The processing stage is discriminated from each of the operation states. If all the flags F1 to F3 and Fx are cleared to “0”,
That is, if all the determinations in steps 102 to 105 are negative, the CPU 41 proceeds to step 106.

【００３５】ステップ１０６に進むと、ＣＰＵ４１は、
パージ制御弁２３を全閉にした後、続くステップ１０７
でキャニスタ閉塞弁２０を全閉にして燃料タンク１２か
ら吸気管２までの区間を密閉化する。図７では、時刻ｔ
１にてパージ制御弁２３が全閉に制御されることで、燃
料タンク１２からパージ制御弁２３までの区間が大気孔
１９を介して大気圧と同じ状態に調整される。また、や
や遅れた時刻ｔ２にてキャニスタ閉塞弁２０が全閉に制
御されることにより、大気圧に調整された密閉区間が形
成される。Upon proceeding to step 106, the CPU 41
After completely closing the purge control valve 23, the following step 107
Then, the canister closing valve 20 is fully closed to seal the section from the fuel tank 12 to the intake pipe 2. In FIG. 7, time t
By controlling the purge control valve 23 to be fully closed at 1, the section from the fuel tank 12 to the purge control valve 23 is adjusted to the same state as the atmospheric pressure via the atmosphere hole 19. Further, at a slightly delayed time t2, the canister shutoff valve 20 is controlled to be fully closed, so that a closed section adjusted to atmospheric pressure is formed.

【００３６】続いて、ＣＰＵ４１は、ステップ１０８で
圧力センサ２５からの入力信号を取り込んで密閉化直後
のタンク内圧「Ｐ１’」を記憶すると共に、ＥＣＵ４０
内蔵のタイマＴをリセットスタートする。また、ＣＰＵ
４１は、次のステップ１０９で前記ステップ１０８にお
けるタイマＴのスタート後、所定時間（本実施の形態で
は、１０秒）が経過したか否かを判別する。Subsequently, the CPU 41 fetches the input signal from the pressure sensor 25 in step 108 and stores the tank internal pressure “P1 ′” immediately after the sealing, and at the same time, the ECU 40
The built-in timer T is reset and started. Also, CPU
In the next step 109, 41 determines whether or not a predetermined time (10 seconds in the present embodiment) has elapsed after the timer T was started in step 108.

【００３７】１０秒経過前であれば、ＣＰＵ４１は、ス
テップ１１０で第１フラグＦ１に「１」をセットし、一
旦本ルーチンを終了する。図７では、時刻ｔ２で第１フ
ラグＦ１がセットされ、それ以降、前記ステップ１０２
が肯定判別されてステップ１０１→１０２→１０９→１
１０の順に処理が実施される。この間、圧力センサ２５
の検出値は、図７の時刻ｔ２〜ｔ３に示すように、燃料
タンク１２内での燃料ガスの発生量に応じて「０ｈＰ
ａ」から徐々に上昇することになる。If 10 seconds have not passed, the CPU 41 sets "1" to the first flag F1 in step 110, and once ends this routine. In FIG. 7, the first flag F1 is set at the time t2, and thereafter, the above step 102 is performed.
Is affirmatively determined and steps 101 → 102 → 109 → 1.
The processing is performed in the order of 10. During this time, the pressure sensor 25
The detected value of "0 hP" is determined according to the amount of fuel gas generated in the fuel tank 12, as shown at times t2 to t3 in FIG.
It will gradually rise from "a".

【００３８】時刻ｔ２から１０秒が経過すると、ＣＰＵ
４１は、ステップ１０９を肯定判別して図４のステップ
１１１に進み、圧力センサ２５からの入力信号を取り込
んでこの時のタンク内圧「Ｐ１”」を記憶すると共に、
続くステップ１１２で密閉化後１０秒間の圧力変化量
（以下、大気圧下変化量という）ΔＰ１を、 ΔＰ１＝Ｐ１”−Ｐ１’ として算出する。また、ＣＰＵ４１は、ステップ１１３
で第１フラグＦ１を「０」にクリアする（図７の時刻ｔ
３）。When 10 seconds have passed from time t2, the CPU
41 makes an affirmative decision in step 109 to proceed to step 111 in FIG. 4, fetch the input signal from the pressure sensor 25 and store the tank internal pressure “P1” ”at this time, and
In subsequent step 112, the pressure change amount (hereinafter referred to as the atmospheric pressure change amount) ΔP1 for 10 seconds after the sealing is calculated as ΔP1 = P1 ″ −P1 ′.
Then, the first flag F1 is cleared to "0" (time t in FIG. 7).
3).

【００３９】その後、ＣＰＵ４１は、ステップ１１４で
パージ制御弁２３を全閉から全開状態に切り換えると共
に、タイマＴをリセットスタートする。パージ制御弁２
３が全開に切り換えられるこの時刻ｔ３では、それまで
の正圧状態下の密閉区間に吸気管負圧が導入されること
になる。従って、パージ通路部分に閉塞による異常がな
ければ、圧力センサ２５の検出値（タンク内圧ＰＴ）が
下降し始める。Thereafter, the CPU 41 switches the purge control valve 23 from the fully closed state to the fully opened state in step 114, and resets and starts the timer T. Purge control valve 2
At this time t3 when 3 is switched to full open, the intake pipe negative pressure is introduced into the closed section under the positive pressure condition up to that point. Therefore, if there is no abnormality due to blockage in the purge passage portion, the detection value of the pressure sensor 25 (tank internal pressure PT) starts to drop.

【００４０】さらに、ＣＰＵ４１は、ステップ１１５で
圧力センサ２５からの入力信号に基づいてタンク内圧Ｐ
Ｔが所定の負圧レベル（本実施の形態では、−２０ｈＰ
ａ）以下になったか否かを判別する。ＰＴ＞−２０ｈＰ
ａと判別される場合（図７の時刻ｔ３〜ｔ４の期間）、
ＣＰＵ４１は、ステップ１１５を否定判別してステップ
１１６に進む。そして、ＣＰＵ４１は、ステップ１１６
で前記ステップ１１４におけるタイマＴのスタート後、
すなわち図７の時刻ｔ３後、所定時間（本実施の形態で
は、２秒）が経過したか否かを判別する。Further, in step 115, the CPU 41 determines the tank internal pressure P based on the input signal from the pressure sensor 25.
T is a predetermined negative pressure level (in the present embodiment, −20 hP
a) Determine whether or not PT> -20hP
When it is determined to be a (the period from time t3 to t4 in FIG. 7),
The CPU 41 makes a negative decision in step 115 and proceeds to step 116. The CPU 41 then proceeds to step 116.
After the timer T is started in step 114,
That is, it is determined whether or not a predetermined time (two seconds in the present embodiment) has elapsed after time t3 in FIG.

【００４１】２秒経過前であれば、ＣＰＵ４１は、ステ
ップ１１７で第２フラグＦ２に「１」をセットする。こ
うして今度は前記図３のステップ１０２が否定判別され
ると共にステップ１０３が肯定判別されるようになり、
ステップ１０１〜１０３→１１５→１１６…の順に処理
が繰り返し実行される。If two seconds have not passed, the CPU 41 sets "1" in the second flag F2 in step 117. In this way, step 102 of FIG. 3 is negatively determined and step 103 is positively determined.
The processing is repeatedly executed in the order of steps 101 to 103 → 115 → 116.

【００４２】なお、ステップ１１５が否定判別される状
態（ＰＴ＞−２０ｈＰａの状態）が継続されたまま、時
刻ｔ３から２秒以上が経過すると、ステップ１１６が肯
定判別され、ＣＰＵ４１はステップ１１８に進む。ＣＰ
Ｕ４１は、ステップ１１８で燃料タンク１２から吸気管
２までのパージ系のどこかに閉塞部分があることを意味
するパージ系閉塞フラグＦclose に「１」をセットする
と共に、異常警告灯２９を点灯させる。If 2 seconds or more elapses from the time t3 while the state where the determination in step 115 is negative (state of PT> -20 hPa) is continued, the determination in step 116 is affirmative and the CPU 41 proceeds to step 118. . CP
In step 118, the U41 sets "1" to the purge system blockage flag Fclose, which means that there is a blockage part in the purge system from the fuel tank 12 to the intake pipe 2, and turns on the abnormality warning light 29. .

【００４３】つまり、パージ系閉塞などの異常が発生し
ていなければ、時刻ｔ３〜ｔ４の期間内にて２秒経過前
にタンク内圧ＰＴが所定の負圧レベル（−２０ｈＰａ）
にまで低下するが、パージ系閉塞などの異常が発生して
いれば、２秒経過後にもタンク内圧ＰＴが所定の負圧レ
ベルにまで低下せず、パージ系閉塞の旨の異常発生が検
出されることになる。That is, unless an abnormality such as a purge system blockage has occurred, the tank internal pressure PT has reached a predetermined negative pressure level (-20 hPa) before the elapse of 2 seconds within the period from time t3 to t4.
However, if an abnormality such as a purge system blockage occurs, the tank internal pressure PT does not drop to a predetermined negative pressure level even after 2 seconds, and an abnormality occurrence indicating the purge system blockage is detected. Will be.

【００４４】一方、前記ステップ１１５が肯定判別され
ると、ＣＰＵ４１は、ステップ１１９で第２フラグＦ２
を「０」にリセットする。また、ＣＰＵ４１は続くステ
ップ１２０で、後述する負圧Ｆ／Ｂ処理の継続時間を計
測するためのカウンタＣの値が所定値Ｋに達したか否か
を判別する。当初はカウンタＣが「０」にクリアされて
いるためにステップ１２０が否定判別され、ＣＰＵ４１
はステップ１２１に進む。On the other hand, when the affirmative determination is made in step 115, the CPU 41 determines in step 119 that the second flag F2.
Is reset to "0". Further, in the subsequent step 120, the CPU 41 determines whether or not the value of the counter C for measuring the duration of negative pressure F / B processing, which will be described later, has reached a predetermined value K. Since the counter C is initially cleared to "0", a negative determination is made in step 120, and the CPU 41
Proceeds to step 121.

【００４５】なおここで、所定値Ｋは例えば図８のマッ
プに従いその都度設定される可変値であって、図８によ
れば、燃料タンク１２内の温度（燃温）が高くなるほ
ど、所定値Ｋが大きい値に設定されるようになってい
る。因みに、燃温は周知の温度センサ（図示略）にて計
測され、その計測結果がＥＣＵ４０に取り込まれるよう
になっている。Here, the predetermined value K is a variable value set each time according to the map of FIG. 8, for example, and according to FIG. 8, the higher the temperature (fuel temperature) in the fuel tank 12, the predetermined value. K is set to a large value. Incidentally, the fuel temperature is measured by a known temperature sensor (not shown), and the measurement result is taken into the ECU 40.

【００４６】ＣＰＵ４１は、ステップ１２１で負圧Ｆ／
ＢフラグＦｘに「１」をセットし、続くステップ２００
で負圧Ｆ／Ｂ処理を実施する。つまり、この負圧Ｆ／Ｂ
処理は図７の時刻ｔ４にて開始され、同処理によれば、
所定期間においてタンク内圧ＰＴが「−２０ｈＰａ」近
傍にＦ／Ｂ制御される。従って、時刻ｔ４以降は、図３
のステップ１０２，１０３が否定判別されると共にステ
ップ１０４が肯定判別されるようになり、ステップ１０
１〜１０４→１２０→１２１→２００の順に処理が繰り
返し実行される。The CPU 41 determines negative pressure F /
B flag Fx is set to "1", and the following step 200
The negative pressure F / B process is carried out. In other words, this negative pressure F / B
The process starts at time t4 in FIG. 7, and according to the process,
The tank internal pressure PT is F / B controlled in the vicinity of “−20 hPa” for a predetermined period. Therefore, after time t4, as shown in FIG.
Steps 102 and 103 are negatively determined, and step 104 is positively determined.
The processing is repeatedly executed in the order of 1 to 104 → 120 → 121 → 200.

【００４７】ここで、ステップ２００にて実施される負
圧Ｆ／Ｂ処理を図６に従い説明する。図６において、Ｃ
ＰＵ４１は、先ずステップ２０１でカウンタＣを「１」
インクリメントし、続くステップ２０２でタンク内圧Ｐ
Ｔが−２０ｈＰａよりも僅かに負圧側のＡ値に達したか
否かを判別する。そして、ＰＴ≦Ａであることを条件に
（ステップ２０２がＹＥＳ）、ＣＰＵ４１は、ステップ
２０３でパージ制御弁２３の開度を開側に制御する。具
体的には、パージ制御弁２３の制御デューティ比を数％
程度増加させる。Now, the negative pressure F / B processing executed in step 200 will be described with reference to FIG. In FIG. 6, C
The PU 41 first sets the counter C to “1” in step 201.
Increment, and in the next step 202, the tank internal pressure P
It is determined whether T has reached the A value on the negative pressure side slightly below -20 hPa. Then, under the condition that PT ≦ A (YES in step 202), the CPU 41 controls the opening degree of the purge control valve 23 to the open side in step 203. Specifically, the control duty ratio of the purge control valve 23 is set to several percent.
Increase the degree.

【００４８】また、ＣＰＵ４１は、ステップ２０４でタ
ンク内圧ＰＴが−２０ｈＰａよりも僅かに正圧側のＢ値
に達したか否かを判別する。そして、ＰＴ≧Ｂであるこ
とを条件に（ステップ２０４がＹＥＳ）、ＣＰＵ４１
は、ステップ２０５でパージ制御弁２３の開度を閉側に
制御する。具体的には、パージ制御弁２３の制御デュー
ティ比を数％程度減少させる。以上図６の処理後、ＣＰ
Ｕ４１は、元の異常検出処理に戻る。Further, the CPU 41 determines in step 204 whether or not the tank internal pressure PT has reached the B value slightly on the positive pressure side of -20 hPa. Then, under the condition that PT ≧ B (YES in step 204), the CPU 41
Controls the opening of the purge control valve 23 to the closed side in step 205. Specifically, the control duty ratio of the purge control valve 23 is reduced by about several percent. After the processing of FIG.
U41 returns to the original abnormality detection processing.

【００４９】そして、前記図６の処理によるカウンタＣ
のカウント動作に伴いＣ＞Ｋとなり、ステップ１２０が
肯定判別されると、ＣＰＵ４１はステップ１２２に進
み、負圧Ｆ／ＢフラグＦｘを「０」にクリアする。さら
に続くステップ１２３でカウンタＣを「０」にクリアす
る。Then, the counter C by the processing of FIG.
C> K due to the counting operation of No., and when the determination at Step 120 is affirmative, the CPU 41 proceeds to Step 122 and clears the negative pressure F / B flag Fx to “0”. In the subsequent step 123, the counter C is cleared to "0".

【００５０】その後、ＣＰＵ４１は、図５のステップ１
２４でパージ制御弁２３を再び全閉に制御する。さら
に、ＣＰＵ４１は、ステップ１２５で圧力センサ２５か
らの入力信号を取り込んで、密閉区間での負圧Ｆ／Ｂ直
後のタンク内圧「Ｐ２’」を記憶すると共にＥＣＵ４０
内蔵のタイマＴをリセットスタートする。このタイミン
グは図７の時刻ｔ５に相当する。After that, the CPU 41 proceeds to step 1 of FIG.
At 24, the purge control valve 23 is fully closed again. Further, the CPU 41 takes in the input signal from the pressure sensor 25 in step 125, stores the tank internal pressure “P2 ′” immediately after the negative pressure F / B in the sealed section, and at the same time, the ECU 40.
The built-in timer T is reset and started. This timing corresponds to time t5 in FIG.

【００５１】要するに、図７の時刻ｔ５では、密閉区間
が−２０ｈＰａの負圧状態に調整され、その後、時刻ｔ
５〜ｔ６の期間では、タンク内圧ＰＴが燃料タンク１２
内での燃料ガスの発生量に応じて−２０ｈＰａ付近から
徐々に上昇していくことになる。In short, at time t5 in FIG. 7, the closed section is adjusted to a negative pressure state of −20 hPa, and then at time t5.
During the period of 5 to t6, the tank internal pressure PT is equal to the fuel tank 12
It gradually rises from around -20 hPa depending on the amount of fuel gas generated therein.

【００５２】次に、ＣＰＵ４１は、ステップ１２６で前
記ステップ１２５におけるタイマＴのスタート後、すな
わち図７の時刻ｔ５後、所定時間（本実施の形態では、
１０秒）が経過したか否かを判別する。１０秒経過前で
あれば、ＣＰＵ４１は、ステップ１２７で第３フラグＦ
３に「１」をセットする。こうして今度は図３のステッ
プ１０２〜１０４が否定判別されると共にステップ１０
５が肯定判別されるようになり、ステップ１０１〜１０
５→１２６→１２７の順に処理が繰り返し実行される。Next, in step 126, the CPU 41 starts the timer T in step 125, that is, after the time t5 in FIG.
It is determined whether (10 seconds) has elapsed. If 10 seconds have not elapsed, the CPU 41 proceeds to step 127 to set the third flag F.
Set “1” to 3. Thus, this time, Steps 102 to 104 of FIG.
5 is affirmatively determined, and steps 101 to 10
The process is repeatedly executed in the order of 5 → 126 → 127.

【００５３】時刻ｔ５から１０秒が経過すると、ＣＰＵ
４１は、ステップ１２６を肯定判別してステップ１２８
に進む。ＣＰＵ４１は、ステップ１２８で圧力センサ２
５からの入力信号を取り込んで、時刻ｔ６でのタンク内
圧「Ｐ２”」を記憶すると共に、続くステップ１２９で
負圧状態下での密閉化後１０秒間の圧力変化量（以下、
負圧下変化量という）ΔＰ２を、 ΔＰ２＝Ｐ２”−Ｐ２’ として算出する。When 10 seconds have passed from time t5, the CPU
41 makes an affirmative decision in step 126 to proceed to step 128.
Proceed to. The CPU 41 determines in step 128 the pressure sensor 2
5, the tank internal pressure "P2""at time t6 is stored, and at step 129, the pressure change amount for 10 seconds after sealing under negative pressure (hereinafter,
ΔP2, which is referred to as the amount of change in negative pressure reduction, is calculated as ΔP2 = P2 ″ −P2 ′.

【００５４】その後、ＣＰＵ４１は、ステップ１３０で
所定のリーク判定条件に基づいてリークが有るか否かを
判別する。具体的には、 ΔＰ２＞α・ΔＰ１＋β が成立する場合、「リーク有り」の旨を判定する。但
し、αは、大気圧と負圧との違いによる燃料蒸発量の差
を補正する係数であり、βは、圧力センサ精度、キャニ
スタ閉塞弁２０の漏れなどを補正する係数である。After that, the CPU 41 determines in step 130 based on a predetermined leak determination condition whether or not there is a leak. Specifically, when ΔP2> α · ΔP1 + β holds, it is determined that “there is a leak”. However, α is a coefficient for correcting the difference in the fuel evaporation amount due to the difference between the atmospheric pressure and the negative pressure, and β is a coefficient for correcting the pressure sensor accuracy, the leakage of the canister blocking valve 20, and the like.

【００５５】つまり、燃料タンク１２からパージ制御弁
２３までの密閉区間にリーク原因が有るならば、正圧状
態下では密閉区間から大気中への流出が起こる一方、負
圧状態下では大気中から密閉区間への流出が起こる。従
って、「大気圧下変化量ΔＰ１」に比べて「負圧下変化
量ΔＰ２」が大きくなる。なおここで、・大気圧下変化量ΔＰ１は、「燃料タンク１２における
燃料ガスの発生量−密閉区間から大気中への流出量」に
相当し、・負圧下変化量ΔＰ２は、「燃料タンク１２における燃
料ガスの発生量＋密閉区間への流入量」に相当する。こ
のことから上記不等式のリーク判定条件が導き出されて
いる。In other words, if there is a cause of leakage in the closed section from the fuel tank 12 to the purge control valve 23, outflow from the closed section to the atmosphere occurs under positive pressure, while from the atmosphere under negative pressure. Outflow to a closed section occurs. Therefore, the “negative pressure change amount ΔP2” becomes larger than the “atmospheric pressure change amount ΔP1”. Here, the atmospheric pressure change amount ΔP1 corresponds to “the amount of fuel gas generated in the fuel tank 12−the amount of outflow from the sealed section into the atmosphere”, and the negative pressure change amount ΔP2 is the “fuel tank 12 Fuel gas generation amount + inflow amount into the closed section ". From this, the leak determination condition of the above inequality is derived.

【００５６】上記不等式のリーク判定条件が不成立の場
合、すなわちステップ１３０が否定判別される場合、Ｃ
ＰＵ４１はステップ１３１に進み、第１〜第３の各フラ
グＦ１〜Ｆ３並びに負圧Ｆ／ＢフラグＦｘを強制的にク
リアして本ルーチンを終了する。If the leak determination condition of the above inequality is not satisfied, that is, if step 130 is negatively determined, C
The PU 41 proceeds to step 131, forcibly clears the first to third flags F1 to F3 and the negative pressure F / B flag Fx, and ends this routine.

【００５７】また、上記不等式のリーク判定条件が成立
する場合、すなわちステップ１３０が肯定判別される場
合、ＣＰＵ４１はステップ１３２に進む。そして、燃料
タンク１２から吸気管２までのパージ系のどこかにリー
ク原因となる部分が有ることを意味するパージ系リーク
フラグＦleakに「１」をセットすると共に、異常警告灯
２９を点灯させ、その後本ルーチンを終了する。When the leak determination condition of the above inequality is satisfied, that is, when step 130 is positively determined, the CPU 41 proceeds to step 132. Then, "1" is set to the purge system leak flag Fleak, which means that there is a part causing the leak somewhere in the purge system from the fuel tank 12 to the intake pipe 2, and the abnormality warning lamp 29 is turned on. Then, this routine ends.

【００５８】以上説明した処理によれば、燃料ガス排出
抑止装置において、燃料タンク１２からパージ制御弁２
３に至るまでの区間にリークや閉塞が発生している場合
には、これが常に的確に検出される。また、この異常検
出は圧力センサ２５の取り付け位置に関係なく実施でき
る。According to the processing described above, in the fuel gas emission restraining apparatus, the purge control valve 2 is removed from the fuel tank 12.
If there is a leak or blockage in the section up to 3, this is always detected accurately. Further, this abnormality detection can be performed regardless of the mounting position of the pressure sensor 25.

【００５９】なお本実施の形態では、前記図３〜図５に
おけるパージ制御弁２３，キャニスタ閉塞弁２０の開閉
制御が請求項記載の圧力調整手段に相当し、図５のステ
ップ１３０が異常検出手段に相当する。また、図４のス
テップ２００（図６の処理）が負圧保持手段に相当し、
図３〜図５における負圧Ｆ／ＢフラグＦｘの操作が異常
検出開始許可手段に相当する。In this embodiment, the opening / closing control of the purge control valve 23 and the canister closing valve 20 in FIGS. 3 to 5 corresponds to the pressure adjusting means described in the claims, and step 130 in FIG. 5 is the abnormality detecting means. Equivalent to. Further, step 200 of FIG. 4 (processing of FIG. 6) corresponds to negative pressure holding means,
The operation of the negative pressure F / B flag Fx in FIGS. 3 to 5 corresponds to abnormality detection start permission means.

【００６０】以上詳述した本実施の形態によれば、以下
に示す特有の効果が得られる。（ａ）本実施の形態では、負圧レベルでの圧力調整直後
に、その際に調整される負圧レベルを所定時間だけその
付近で保持し（前記図７の時刻ｔ４〜ｔ５）、所定時間
の負圧保持後、異常検出のための圧力状態の検出を開始
するようにした（図７の時刻ｔ５〜ｔ６）。かかる構成
によれば、急激な燃料ガスの発生が収まってから異常判
定が実施されるため、予期せぬ燃料ガスの多量発生によ
り不用意な圧力変化が生じることがなく、圧力状態の変
化から精度良くリーク判定が実施できる。その結果、微
細孔による燃料ガスの漏れ時にもその異常を正確に検出
することができるようになる。According to this embodiment described in detail above, the following unique effects can be obtained. (A) In the present embodiment, immediately after the pressure adjustment at the negative pressure level, the negative pressure level adjusted at that time is held in the vicinity thereof for a predetermined time (time t4 to t5 in FIG. 7), and the predetermined time is maintained. After the negative pressure is maintained, the detection of the pressure state for the abnormality detection is started (time t5 to t6 in FIG. 7). According to this configuration, since the abnormality determination is performed after the sudden generation of the fuel gas is stopped, there is no unintentional pressure change due to the unexpected generation of a large amount of fuel gas, and the accuracy can be obtained from the change in the pressure state. Good leak judgment can be performed. As a result, even when the fuel gas leaks through the fine holes, the abnormality can be accurately detected.

【００６１】図９（ａ），（ｂ）は、本実施の形態にお
ける効果を確認するための図であり、同図の縦軸が負圧
下変化量ΔＰ２を示し、横軸が燃料タンク１２内の燃料
量を示す。また、同図（ａ）は、本実施の形態の装置に
おける実験結果を、（ｂ）は従来装置（負圧保持をしな
い装置）における実験結果を示しており、各図におい
て、・「×」印は、φ１．０ｍｍのリークが有る時のデータ
を、・「▲」印は、φ０．５ｍｍのリークが有る時のデータ
を、・「○」印は、リークが無い時のデータを、それぞれ示す。9 (a) and 9 (b) are views for confirming the effect of the present embodiment, in which the vertical axis shows the negative pressure change amount ΔP2 and the horizontal axis shows the inside of the fuel tank 12. Shows the fuel amount of. Further, (a) of the figure shows the experimental result in the device of the present embodiment, and (b) shows the experimental result in the conventional device (device which does not maintain negative pressure). The mark shows the data when there is a leak of φ1.0 mm, ・ “▲” shows the data when there is a leak of φ0.5 mm, and “○” shows the data when there is no leak. Show.

【００６２】各印のデータを見ると、「×」印のデータ
は明らかに他のデータと区別できるが、「▲」印及び
「○」のデータはそれぞれ、図９（ａ）のＡ１〜Ａ３，
Ｂ１〜Ｂ３、図９（ｂ）のＣ１〜Ｃ３，Ｄ１〜Ｄ３の範
囲に点在し、特に図９（ｂ）ではＣ１〜Ｃ３とＤ１〜Ｄ
３とが互いに重なることもあって両データを区別するこ
とは非常に困難となる。これに対し、図９（ａ）ではＡ
１〜Ａ３とＢ１〜Ｂ３とが区別でき、微細孔（φ０．５
ｍｍ）のリークと、リーク無しとが明確に識別できるこ
とになる。Looking at the data of each mark, the data of "x" is clearly distinguishable from other data, but the data of "▲" and "○" are respectively A1 to A3 in FIG. 9A. ，
B1 to B3 and C1 to C3 and D1 to D3 in FIG. 9B are scattered, and particularly C1 to C3 and D1 to D in FIG. 9B.
Since 3 and 3 overlap each other, it is very difficult to distinguish both data. On the other hand, in FIG.
1 to A3 and B1 to B3 can be distinguished, and fine holes (φ0.5
(mm) leak and no leak can be clearly distinguished.

【００６３】（ｂ）また本実施の形態では、キャニスタ
１６と吸気管２との間のパージ制御弁２３の開度をデュ
ーティ制御して密閉区間内の圧力を所定の負圧レベルに
保持した。同構成によれば、密閉区間での負圧保持が適
正に実施できる。(B) Further, in the present embodiment, the opening degree of the purge control valve 23 between the canister 16 and the intake pipe 2 is duty-controlled to maintain the pressure in the closed section at a predetermined negative pressure level. According to this configuration, negative pressure can be properly maintained in the closed section.

【００６４】（ｃ）燃料タンク１２内の燃料温度に応じ
て所定の負圧レベルで保持する時間を可変に設定した
（前記図８のマップ参照）。この場合、燃料ガスの発生
度合いに対応させつつ、適切な負圧保持の制御が実現で
きる。(C) The time for holding at a predetermined negative pressure level is variably set according to the fuel temperature in the fuel tank 12 (see the map in FIG. 8). In this case, it is possible to realize appropriate control of holding the negative pressure while corresponding to the generation degree of the fuel gas.

【００６５】（ｄ）燃料タンク１２から吸気管２までの
密閉化の際に、大気圧（第１の所定圧力）と−２０ｈＰ
ａ（第２の所定圧力）とを切り換えて、各々の圧力での
圧力変化状態の比較結果からリーク等の異常を検出し
た。かかる場合、仮にリーク原因が存在するのであれ
ば、各圧力の調整時に大気圧との相対的な圧力差の違い
に応じてリーク速度が変化する。従って、上記２つの圧
力変化状態の差によれば、リークの有無やリーク原因が
容易に検出できる。(D) At the time of sealing the fuel tank 12 to the intake pipe 2, the atmospheric pressure (first predetermined pressure) and -20 hP.
By switching a (second predetermined pressure), an abnormality such as a leak was detected from the comparison result of the pressure change states at each pressure. In this case, if the cause of the leak exists, the leak rate changes according to the difference in relative pressure difference from the atmospheric pressure when adjusting each pressure. Therefore, according to the difference between the two pressure change states, the presence or absence of leak and the cause of leak can be easily detected.

【００６６】なお、本発明の実施の形態は、上記以外に
次の形態にて実現できる。上記実施の形態では、負圧保
持時間に相当する所定値Ｋを、前記図８の関係に従い燃
温（燃料温度）に応じて可変に設定したが、この構成を
以下の（イ）〜（ハ）のように変更する。In addition to the above, the embodiment of the present invention can be realized in the following forms. In the above embodiment, the predetermined value K corresponding to the negative pressure holding time is variably set according to the fuel temperature (fuel temperature) according to the relationship of FIG. 8. However, this configuration has the following (a) to (c). ) Is changed.

【００６７】（イ）燃料タンク１２内の空間容積に係る
パラメータに応じて所定値Ｋを可変に設定する。この場
合、図１０に示されるように、燃料タンク１２内の空間
容積が大きくなるほど、所定値Ｋを大きくするとよい。
因みに空間容積は、燃料タンク１２に取り付けられる燃
料レベルゲージの計測結果を基に算出され、同レベルゲ
ージにより計測される燃料残量が多いほど空間容積は小
さく、燃料残量が少ないほど空間容積は大きくなる。(A) The predetermined value K is variably set according to the parameter related to the space volume in the fuel tank 12. In this case, as shown in FIG. 10, the predetermined value K may be increased as the space volume in the fuel tank 12 increases.
Incidentally, the space volume is calculated based on the measurement result of the fuel level gauge attached to the fuel tank 12, and the larger the fuel remaining amount measured by the level gauge, the smaller the space volume, and the smaller the fuel remaining amount, the space volume. growing.

【００６８】仮に空間容積が大きい場合、すなわち燃料
残量が少ない場合、図１０のマップから所定値Ｋは大き
な値が設定される。これにより、図１２に示されるよう
に、負圧Ｆ／Ｂが継続される時間が比較的長い時間で設
定される（時刻ｔ４〜ｔ１５）。そしてその後、時刻ｔ
１６では負圧下変化量ΔＰ２が算出され、そのΔＰ２値
から異常検出が行われる。負圧Ｆ／Ｂの継続時間が二点
鎖線で示す「ｔ４〜ｔ５」よりも延長されて「ｔ４〜ｔ
１５」となる場合、燃料蒸発ガスの発生がより安定した
状態で負圧下変化量ΔＰ２が計測される。そのため、燃
料蒸発ガスの影響を低減し、信頼性の高いリーク検出が
実施できる。If the space volume is large, that is, if the remaining amount of fuel is small, the predetermined value K is set to a large value from the map of FIG. As a result, as shown in FIG. 12, the time during which the negative pressure F / B is continued is set to a relatively long time (time t4 to t15). And after that, at time t
In 16, the negative pressure change amount ΔP2 is calculated, and the abnormality is detected from the ΔP2 value. The duration of the negative pressure F / B is extended from "t4 to t5" indicated by the chain double-dashed line to "t4 to t".
In the case of 15 ”, the negative pressure change amount ΔP2 is measured in a state where the generation of the fuel evaporative gas is more stable. Therefore, the influence of the fuel evaporative emission can be reduced, and highly reliable leak detection can be performed.

【００６９】（ロ）燃料性状に応じて所定値Ｋを可変に
設定する。この場合、図１１に示されるように、ガソリ
ン燃料のリード蒸気圧（ＲＶＰ）が大きくなるほど、所
定値Ｋを大きくするとよい。因みにリード蒸気圧は、燃
料タンク１２等に取り付けられるガソリン性状センサの
計測結果を基に算出される。(B) The predetermined value K is variably set according to the fuel property. In this case, as shown in FIG. 11, the predetermined value K may be increased as the Reid vapor pressure (RVP) of the gasoline fuel increases. Incidentally, the Reid vapor pressure is calculated based on the measurement result of the gasoline property sensor attached to the fuel tank 12 or the like.

【００７０】（ハ）負圧導入時の圧力勾配又は所要時間
に応じて所定値Ｋを可変に設定する。具体的には、前記
図７のリークチェック期間内においてタンク内圧ＰＴを
所定の負圧値（−２０ｈＰａ）にまで変化させる際の所
要時間（前記図７の時刻ｔ３〜ｔ４の時間）を求め、そ
の所要時間に応じて所定値Ｋを設定する。このとき、所
定負圧までの所要時間が長いほど、燃料ガスの時間当た
りの発生量が多いとして所定値Ｋを大きくする。又は、
同じくリークチェック期間内の負圧変化時（図７の時刻
ｔ３〜ｔ４）においてその時の圧力勾配を求め、その圧
力勾配に応じて所定値Ｋを設定する。このとき、圧力勾
配が小さいほど、燃料ガスの時間当たりの発生量が多い
として所定値Ｋを大きくする。(C) The predetermined value K is variably set according to the pressure gradient or the required time when the negative pressure is introduced. Specifically, the time required to change the tank internal pressure PT to a predetermined negative pressure value (−20 hPa) in the leak check period of FIG. 7 (time t3 to t4 of FIG. 7) is calculated, The predetermined value K is set according to the required time. At this time, the longer the time required to reach the predetermined negative pressure is, the larger the amount of fuel gas generated per time is, and the predetermined value K is increased. Or
Similarly, when the negative pressure changes within the leak check period (time t3 to t4 in FIG. 7), the pressure gradient at that time is obtained, and the predetermined value K is set according to the pressure gradient. At this time, the smaller the pressure gradient is, the larger the amount of fuel gas generated per time is, and the predetermined value K is increased.

【００７１】上記（イ）〜（ハ）の各構成によれば、燃
料ガスの発生度合いに対応させつつ、適切な負圧保持の
制御が実現できる。なお、燃温、タンク内空間容積（燃
料残量）、燃料性状、負圧導入時の圧力勾配などを複合
的に用い、これら複数の要素から所定値Ｋを求めること
も可能であり、こうして複数の要素を用いることで異常
検出の信頼性が向上する。また一方で、所定値Ｋを固定
値として具体化することも可能である。According to each of the above configurations (a) to (c), it is possible to realize appropriate control of maintaining the negative pressure while corresponding to the generation degree of the fuel gas. Note that it is also possible to use a plurality of elements such as the fuel temperature, the tank internal volume (remaining fuel amount), the fuel property, and the pressure gradient at the time of introducing the negative pressure to obtain the predetermined value K. The reliability of abnormality detection is improved by using the element. On the other hand, it is possible to embody the predetermined value K as a fixed value.

【００７２】上記実施の形態では、図３〜図５のフロー
チャートにて実施される異常検出処理において、大気圧
付近の圧力変化状態を計測した後、負圧での圧力変化状
態を計測したが、この順序を逆にしてもよい。In the above-described embodiment, in the abnormality detection process executed in the flowcharts of FIGS. 3 to 5, after measuring the pressure change state near atmospheric pressure, the pressure change state at negative pressure is measured. This order may be reversed.

【００７３】前記異常検出処理における圧力調整の時間
（前記図７の時刻ｔ２〜ｔ３，ｔ３〜ｔ４，ｔ５〜ｔ６
の時間）は既述の時間に限定されるものではなく、エン
ジン仕様などに応じて適宜変更して具体化してもよい。
但し、上述の通り大気圧付近の圧力変化量と負圧域での
圧力変化量との比較により異常検出を行う場合、各圧力
変化量の検出期間（図７の時刻ｔ２〜ｔ３，ｔ５〜ｔ
６）を一致させるか、各時間を互いに対応付けた時間と
して設定するのが望ましい。Time for pressure adjustment in the abnormality detection process (time t2 to t3, t3 to t4, t5 to t6 in FIG. 7).
The time) is not limited to the above-mentioned time, and may be embodied by appropriately changing it according to the engine specifications and the like.
However, when abnormality detection is performed by comparing the pressure change amount near the atmospheric pressure and the pressure change amount in the negative pressure region as described above, the detection period of each pressure change amount (time t2 to t3, t5 to t5 in FIG. 7).
It is desirable to match 6) or set each time as a time associated with each other.

【００７４】また、上記実施の形態では、大気圧付近の
圧力変化量（ΔＰ１）と負圧域での圧力変化量（ΔＰ
２）との比較により異常検出を行ったが、少なくとも負
圧域での圧力変化量を検出し、その圧力変化量だけで異
常検出を行うように構成する。この場合、実験等により
予め設定しておいた判定値を使って、負圧域での圧力変
化量から正常／異常の判定を行う。この構成にあって
も、負圧域での圧力調整時にその負圧レベルを所定時間
だけ保持し、その後、異常検出のための圧力状態の検出
を開始することで、上記実施の形態と同様に、微細孔に
よる燃料ガスの漏れ時にもその異常を正確に検出するこ
とができるなどの優れた効果が得られる。In the above embodiment, the pressure change amount (ΔP1) near the atmospheric pressure and the pressure change amount (ΔP1) in the negative pressure region are set.
Although the abnormality detection is performed by comparison with 2), the pressure change amount is detected at least in the negative pressure range, and the abnormality detection is performed only by the pressure change amount. In this case, a normal / abnormal determination is made from the pressure change amount in the negative pressure region, using a determination value set in advance by experiments or the like. Even in this configuration, the negative pressure level is maintained for a predetermined time when the pressure is adjusted in the negative pressure region, and thereafter, the detection of the pressure state for the abnormality detection is started, so that the same as in the above-described embodiment. Even when the fuel gas leaks due to the fine holes, it is possible to obtain an excellent effect that the abnormality can be accurately detected.

【００７５】上記実施の形態では、圧力検出手段として
の圧力センサ２５を燃料タンク１２に設けたが、例えば
この圧力センサ２５をキャニスタ１６と吸気管２との間
の区間に設けるようにしてもよい。この場合にも、密閉
区間を構成した上での圧力変化状態に基づき、密閉区間
全体のリーク判定を行うことが可能となる。In the above embodiment, the pressure sensor 25 as the pressure detecting means is provided in the fuel tank 12, but the pressure sensor 25 may be provided in the section between the canister 16 and the intake pipe 2, for example. . Also in this case, it is possible to determine the leak of the entire closed section based on the pressure change state after the closed section is configured.

【図面の簡単な説明】[Brief description of drawings]

【図１】発明の実施の形態における燃料噴射制御システ
ムの概要を示す構成図。FIG. 1 is a configuration diagram showing an outline of a fuel injection control system according to an embodiment of the invention.

【図２】パージ制御弁のデューティ駆動態様を示すグラ
フ。FIG. 2 is a graph showing a duty driving mode of a purge control valve.

【図３】異常検出処理を示すフローチャート。FIG. 3 is a flowchart showing an abnormality detection process.

【図４】図３に続き、異常検出処理を示すフローチャー
ト。FIG. 4 is a flowchart showing anomaly detection processing continued from FIG. 3;

【図５】図３，図４に続き、異常検出処理を示すフロー
チャート。FIG. 5 is a flowchart showing anomaly detection processing subsequent to FIGS. 3 and 4;

【図６】負圧Ｆ／Ｂ処理を示すフローチャート。FIG. 6 is a flowchart showing negative pressure F / B processing.

【図７】異常検出処理の実施過程を説明するためのタイ
ムチャート。FIG. 7 is a time chart for explaining an implementation process of abnormality detection processing.

【図８】燃温に応じて、負圧保持時間に相当する所定値
Ｋを設定するためのマップ。FIG. 8 is a map for setting a predetermined value K corresponding to a negative pressure holding time according to the fuel temperature.

【図９】実施の形態における効果を説明するためのグラ
フ。FIG. 9 is a graph for explaining the effect of the embodiment.

【図１０】燃料タンクの空間容積に応じて、負圧保持時
間に相当する所定値Ｋを設定するためのマップ。FIG. 10 is a map for setting a predetermined value K corresponding to a negative pressure holding time according to the space volume of the fuel tank.

【図１１】ガソリンＲＶＰに応じて、負圧保持時間に相
当する所定値Ｋを設定するためのマップ。FIG. 11 is a map for setting a predetermined value K corresponding to a negative pressure holding time according to gasoline RVP.

【図１２】異常検出処理の実施過程を説明するためのタ
イムチャート。FIG. 12 is a time chart for explaining an implementation process of abnormality detection processing.

[Explanation of symbols]

１…エンジン（内燃機関）、２…吸気管、１２…燃料タ
ンク、１５…連通管、１６…キャニスタ、２０…キャニ
スタ閉塞弁、２２，２４…パージ配管、２３…パージ制
御弁、２５…圧力センサ、４０…ＥＣＵ（電子制御装
置）、４１…圧力調整手段，異常検出手段，負圧保持手
段，異常検出開始許可手段を構成するＣＰＵ。DESCRIPTION OF SYMBOLS 1 ... Engine (internal combustion engine), 2 ... Intake pipe, 12 ... Fuel tank, 15 ... Communication pipe, 16 ... Canister, 20 ... Canister closing valve, 22, 24 ... Purge piping, 23 ... Purge control valve, 25 ... Pressure sensor , 40 ... ECU (electronic control unit), 41 ... CPU constituting pressure adjusting means, abnormality detecting means, negative pressure holding means, and abnormality detection start permitting means.

フロントページの続き (56)参考文献特開平９−291854（ＪＰ，Ａ) (58)調査した分野(Int.Cl.⁷，ＤＢ名) F02M 25/08 F02M 25/08 301 F02D 41/22 325 Continuation of front page (56) Reference JP-A-9-291854 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F02M 25/08 F02M 25/08 301 F02D 41/22 325

Claims

(57) [Claims]

1. A fuel gas emission control device for storing fuel gas generated in a fuel tank in a canister, and discharging the fuel gas stored in the canister together with air into an intake passage of an engine through a purge pipe. And a pressure adjusting means for sealing the fuel tank to the intake passage of the engine and adjusting the pressure in the closed section to a predetermined negative pressure level, and after the pressure adjustment by the pressure adjusting means, In an abnormality detecting device comprising an abnormality detecting means for detecting an abnormality of the fuel gas emission suppressing device from a pressure change, a negative pressure level adjusted at that time immediately after pressure adjustment at a negative pressure level by the pressure adjusting means. A negative pressure holding means for holding for a predetermined time in the vicinity thereof, and after the negative pressure holding means holds the negative pressure for a predetermined time, the abnormality for starting the detection of the pressure state for the abnormality detection is started. A detection start permitting means , wherein the negative pressure holding means is the canister and the intake passage of the engine.
The opening of the purge control valve provided in the purge pipe between
By controlling the duty, the pressure in the closed section is adjusted to the specified negative pressure level.
An abnormality detection device for a fuel gas emission suppression device, which is characterized in that

2. The negative pressure holding means is provided in the fuel tank.
Depending on the fuel temperature, the time to hold at a predetermined negative pressure level
The abnormality detection device for a fuel gas emission suppression device according to claim 1, wherein the abnormality detection device is variably set .

3. The negative pressure holding means is an empty space of the fuel tank.
Depending on the parameters related to the volume
The abnormality detection device for a fuel gas emission suppression device according to claim 1 , wherein the holding time is set to be variable .

4. The negative pressure holding means is provided depending on a fuel property.
A variable negative pressure level holding time is set.
An abnormality detection device for the fuel gas emission suppression device according to 1 .

5. From the fuel tank to the intake passage of the engine
In addition to the pressure adjustment at the negative pressure level mentioned above,
Adjust the pressure at another pressure level different from the negative pressure level of
The pressure change condition of the former pressure adjustment and the latter pressure adjustment
Comparing the pressure change state of sage, said from the comparison result
Claim 1- Claim which detects the abnormality of a fuel gas discharge restraint device
Item 5. An abnormality detection device for a fuel gas emission suppression device according to any one of items 4 .

6. The fuel gas generated in the fuel tank is stored in a canister.
The fuel gas stored in the canister to the air.
Along with it, it will be discharged to the intake passage of the engine through the purge pipe.
It is applied to the fuel gas emission control device, and if the fuel tank and the intake passage of the engine are sealed.
Together, the pressure in the closed section is adjusted to a predetermined negative pressure level.
And the pressure change at that time after adjusting the pressure by the pressure adjusting means.
Detection of abnormality in the fuel gas emission control device
In the abnormality detecting and means, after the pressure adjustment in the negative pressure level by the pressure adjustment means
The negative pressure level adjusted at that time for a predetermined time
Negative pressure holding means for holding near the negative pressure holding means and the different pressure after holding the negative pressure for a predetermined time by the negative pressure holding means.
Start detection of pressure condition for normal detection Start of abnormality detection
Permitting means, and the negative pressure holding means responds to the fuel temperature in the fuel tank.
Then, set the time for holding at the specified negative pressure level to be variable.
Abnormality detecting device for that fuel emission control device.

7. The fuel gas generated in the fuel tank is stored in a canister.
The fuel gas stored in the canister to the air.
Along with it, it is discharged to the intake passage of the engine through the purge pipe.
It is applied to the fuel gas emission control device, and if the fuel tank and the intake passage of the engine are sealed.
Together, the pressure in the closed section is adjusted to a predetermined negative pressure level.
And the pressure change at that time after adjusting the pressure by the pressure adjusting means.
Detection of abnormality in the fuel gas emission control device
In the abnormality detecting and means, after the pressure adjustment in the negative pressure level by the pressure adjustment means
The negative pressure level adjusted at that time for a predetermined time
The negative pressure holding means for holding the negative pressure holding means in the vicinity and the negative pressure holding means for holding the negative pressure for a predetermined time after the different pressure
Start detection of pressure condition for normal detection Start of abnormality detection
Permitting means, and the negative pressure holding means relates to the space volume of the fuel tank.
Time to hold at a predetermined negative pressure level according to the parameter
An abnormality detection device for a fuel gas emission suppression device.

8. A fuel gas generated in a fuel tank is stored in a canister.
The fuel gas stored in the canister to the air.
Along with it, it is discharged to the intake passage of the engine through the purge pipe.
It is applied to the fuel gas emission control device, and if the fuel tank and the intake passage of the engine are sealed.
Together, the pressure in the closed section is adjusted to a predetermined negative pressure level.
And the pressure change at that time after adjusting the pressure by the pressure adjusting means.
Detection of abnormality in the fuel gas emission control device
In the abnormality detecting and means, after the pressure adjustment in the negative pressure level by the pressure adjustment means
The negative pressure level adjusted at that time for a predetermined time
The negative pressure holding means for holding the negative pressure holding means in the vicinity and the negative pressure holding means for holding the negative pressure for a predetermined time after the different pressure
Start detection of pressure condition for normal detection Start of abnormality detection
The negative pressure holding means is provided with a predetermined negative pressure level according to the fuel property.
An abnormality detection device for a fuel gas emission suppression device that variably sets the holding time .

9. A fuel gas generated in a fuel tank is stored in a canister.
The fuel gas stored in the canister to the air.
Along with it, it will be discharged to the intake passage of the engine through the purge pipe.
It is applied to the fuel gas emission control device, and if the fuel tank and the intake passage of the engine are sealed.
Together, the pressure in the closed section is adjusted to a predetermined negative pressure level.
And the pressure change at that time after adjusting the pressure by the pressure adjusting means.
Detection of abnormality in the fuel gas emission control device
In the abnormality detecting and means, after the pressure adjustment in the negative pressure level by the pressure adjustment means
The negative pressure level adjusted at that time for a predetermined time
The negative pressure holding means for holding the negative pressure holding means in the vicinity and the negative pressure holding means for holding the negative pressure for a predetermined time after the different pressure
Start detection of pressure condition for normal detection Start of abnormality detection
And a permitting means for sealing the fuel tank to the intake passage of the engine.
In addition to the pressure adjustment at the negative pressure level,
Pressure adjustment at another pressure level different from
Pressure change state during pressure adjustment and the latter pressure adjustment
Compared with the change state, the fuel gas exhaust
An abnormality detection device for a fuel gas emission suppression device that detects an abnormality in the emission suppression device.

10. The fuel gas generated in the fuel tank is stored in the tank.
Store the fuel gas in the canister and empty the fuel gas stored in the canister.
Discharge to the intake passage of the engine along with air through the purge pipe
It is applied to the fuel gas emission restraint device, and when the fuel tank to the intake passage of the engine is sealed
Together, the pressure in the closed section is adjusted to a predetermined negative pressure level.
And the pressure change at that time after adjusting the pressure by the pressure adjusting means.
Detection of abnormality in the fuel gas emission control device
In the abnormality detecting and means, after the pressure adjustment in the negative pressure level by the pressure adjustment means
The negative pressure level adjusted at that time for a predetermined time
The negative pressure holding means for holding the negative pressure holding means in the vicinity and the negative pressure holding means for holding the negative pressure for a predetermined time after the different pressure
Start detection of pressure condition for normal detection Start of abnormality detection
In the purge pipe between the permitting means and the canister and the intake passage of the engine
To adjust the purge flow rate to the provided intake passage
Of the purge control valve, and the negative pressure maintaining means controls the opening degree of the purge control valve.
Tee control to bring the pressure in the closed section to near the specified target negative pressure.
Different for fuel gas emission control device characterized by holding
Always detection device.

11. The fuel gas generated in the fuel tank is stored in the tank.
Store the fuel gas in the canister and empty the fuel gas stored in the canister.
Discharge to the intake passage of the engine along with air through the purge pipe
It is applied to the fuel gas emission restraint device, and when the fuel tank to the intake passage of the engine is sealed
Together, the pressure in the closed section is adjusted to a predetermined negative pressure level.
And the pressure change at that time after adjusting the pressure by the pressure adjusting means.
Detection of abnormality in the fuel gas emission control device
In the abnormality detecting and means, after the pressure adjustment in the negative pressure level by the pressure adjustment means
The negative pressure level adjusted at that time for a predetermined time
The negative pressure holding means for holding the negative pressure holding means in the vicinity and the negative pressure holding means for holding the negative pressure for a predetermined time after the different pressure
Start detection of pressure condition for normal detection Start of abnormality detection
In the purge pipe between the permitting means and the canister and the intake passage of the engine
To adjust the purge flow rate to the provided intake passage
Of the purge control valve, and the negative pressure maintaining means controls the opening degree of the purge control valve.
Control the tee to adjust the pressure in the closed section to the first predetermined pressure and the second
Fuel gas, characterized in that it is held between a predetermined pressure and
Anomaly detection device for emission control device.

12. The fuel gas generated in the fuel tank is stored in the tank.
Store the fuel gas in the canister and empty the fuel gas stored in the canister.
Discharge to the intake passage of the engine along with air through the purge pipe
It is applied to the fuel gas emission restraint device, and when the fuel tank to the intake passage of the engine is sealed
Together, the pressure in the closed section is adjusted to a predetermined negative pressure level.
And the pressure change at that time after adjusting the pressure by the pressure adjusting means.
Detection of abnormality in the fuel gas emission control device
In the abnormality detecting and means, after the pressure adjustment in the negative pressure level by the pressure adjustment means
The negative pressure level adjusted at that time for a predetermined time
The negative pressure holding means for holding the negative pressure holding means in the vicinity and the negative pressure holding means for holding the negative pressure for a predetermined time after the different pressure
Start detection of pressure condition for normal detection Start of abnormality detection
In the purge pipe between the permitting means and the canister and the intake passage of the engine
To adjust the purge flow rate to the provided intake passage
Of the purge control valve, and the negative pressure maintaining means controls the opening degree of the purge control valve.
Tee control to adjust the pressure in the closed section to the specified target negative pressure.
The first predetermined pressure on the positive pressure side and the predetermined target negative pressure
It is maintained between the second predetermined pressure on the negative pressure side and
Anomaly detection device for fuel gas emission control device.