JP2005023869A

JP2005023869A - Liquefied gas fuel supply device for engine

Info

Publication number: JP2005023869A
Application number: JP2003191622A
Authority: JP
Inventors: Kazuhisa Makabe; 和久真壁; Masahiko Toubo; 正彦当房
Original assignee: Nikki Co Ltd
Current assignee: Nikki Co Ltd
Priority date: 2003-07-04
Filing date: 2003-07-04
Publication date: 2005-01-27

Abstract

<P>PROBLEM TO BE SOLVED: To prevent bad conditions, stops or difficulty of restarting of an engine due to operation exceeding liquefied gas vaporization capacity of a regulator at a stage of low engine cooling water temperature. <P>SOLUTION: Engine cooling water temperature is detected by a temperature sensor 32, the maximum vaporized gas quantity that can be generated by the regulator at the temperature is calculated. Notification not to depress an accelerator pedal 21 is given to an operator by an indicator 38 or a speaker 39 until the maximum demand fuel flow rate of the engine 11 is reached and idling speed is maintained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は液化ガスを所定圧力に減圧気化させてエンジンに供給する装置、詳しくは低温始動から暖機運転の期間に液化ガス気化能力を超える量の燃料を要求する運転を禁止する手段を具え、暖機途中における運転を安定よく行なわせるようにしたエンジンの液化ガス燃料供給装置に関するものである。
【０００２】
【従来の技術】
ボンベ内の液化ガスをレギュレータで所定圧力に減圧した気化ガスとして吸気管路に送出しエンジンに供給する液化ガス燃料供給装置は周知であり、レギュレータはエンジン冷却水を用いて液化ガスを加熱気化するとともに気化ガスを所定圧力、即ちほぼ大気圧に調整して吸気管路に設置したミキサに送るか、または一定正圧に調整して吸気管路に設置した燃料噴射弁を送るものである。
【０００３】
このため、エンジン冷却水の温度が低い低温始動時には暖機がかなり進むまでは気化能力が低いため少量の液化ガスしか気化させることができず、始動直後に暖機不充分状態でエンジン回転速度を上昇、例えば自動車を走行させると、液化ガスの一部が気化されずにレギュレータを通過し液体のまま吸気管路に送出されて混合気過濃によるエンジン不調やエンジン停止、あるいは再始動困難という不都合を生じる。
【０００４】
その対策として、エンジン冷却水の温度が低いときはボンベ内の気相部分から気化ガスを取り出してレギュレータに送入し、温度が或る程度上昇したとき液相部分から液化ガスを取り出して気相部分からの気化ガスと一緒にレギュレータに送入することが特開平１０−２５２５６９号公報、特開平１１−２５７１９５号公報に記載されている。この対策によると、液化ガスが少量であるため低い気化能力でも完全に気化させることができ、暖機不充分状態でエンジン回転速度を支障なく上昇させることが可能である。
【０００５】
別の対策として、レギュレータに電熱を使用する加熱手段を併設し、エンジン冷却水のみでは気化能力が不足する温度域であってもかなりの量の液化ガスを気化可能とすることが、特開平５−２２３０１４号公報、特開平１１−３２４８１３号公報に記載されており、この対策によっても暖機不充分状態でエンジン回転速度を支障なく上昇させることが可能である。
【０００６】
【発明が解決しようとする課題】
しかしながら、実際のエンジン運転にあたって運転者は暖機進行度合いを水温計で知ることができても、そのときのレギュレータが持っている気化能力を知らないのでエンジン回転速度を気化能力を越えて上昇させることがあると、液化ガスが液体のまま吸気管路に送出されて前述の不都合を生じてしまう。
【０００７】
本発明は液化ガスをレギュレータでエンジン冷却水により加熱気化するとともに所定圧力の気化ガスに調整して吸気管路に送出しエンジンに供給する液化ガス燃料供給装置について、低温時の始動直後であって暖機不充分の状態のときにエンジン回転速度上昇を可能とするために提案された前記各対策手段では、レギュレータの気化能力を運転者が知らないために気化能力を越えた燃料流量を要求する回転速度に上昇させる運転を行なう場合があることを避けられず、このようなとき液化ガスが液体のまま吸気管路に送出されてエンジン不調などの不都合を生じる、という前述の課題を解決するためになされたものであって、要求燃料流量がレギュレータの気化能力を越えないようにエンジン回転速度を制限して暖機途中における運転を安定よく行わせることができるものとすることを目的とする。
【０００８】
【課題を解決するための手段】
本発明はエンジン冷却水の温度に基いてレギュレータで生成可能な最大気化ガス量を求める気化能力算定手段と、算定した最大気化ガス量が予め設定したエンジン要求燃料流量に達したか否かを判断する任意運転可否判定手段と、この任意運転可否判定手段が任意運転否としている間はエンジン回転速度を制限させる運転制限手段とを具えたことをもって前記課題を解決するための第一手段とした。
【０００９】
また、液化ガスの組成を求める組成算出手段と、算出した液化ガスの組成およびエンジン冷却水の温度に基いてレギュレータで生成可能な最大気化ガス量を求める気化能力算出手段と、算出した最大気化ガス量が予め設定したエンジン要求燃料流量に達したか否かを判断する任意運転可否判定手段と、この任意運転可否判定手段が任意運転否としている間はエンジン回転速度を制限させる運転制限手段とを具えさせたことをもって前記課題を解決するための第二手段とした。
【００１０】
或いは、エンジン冷却水の温度に基いてレギュレータで生成可能な最大気化ガス量を求める気化能力算定手段と、算定した最大気化ガス量で運転可能なエンジン最高回転速度を求める回転速度上限算出手段と、この回転速度上限算出手段で求めた最高回転速度が予め設定した回転速度に達したか否かを判断する任意運転可否決定手段と、この任意運転可否決定手段が任意運転否としている間はエンジン回転速度を制限させる運転制限手段とを具えさせたことをもって前記課題を解決するための第三手段とした。
【００１１】
或いはまた、液化ガスの組成を求める組成算出手段と、算出した液化ガスの組成およびエンジン冷却水の温度に基いてレギュレータで生成可能な最大気化ガス量を求める気化能力算出手段と、算出した最大気化ガス量で運転可能なエンジン最高回転速度を求める回転速度上限算出手段と、この回転速度上限算出手段で求めた最高回転速度が予め設定した回転速度に達したか否かを判断する任意運転可否決定手段と、この任意運転可否決定手段が任意運転否としている間はエンジン回転速度を制限させる運転制限手段とを具えさせたことをもって前記課題を解決するための第四手段とした。
【００１２】
このように、エンジン冷却水温度に依存するレギュレータの液化ガス気化能力が充分なものとなるまでエンジン回転速度を制限させるものとした本発明によると、気化能力を越える燃料流量を要求する運転が行なわれることを防止し、暖機運転を混合気過濃によるエンジン不調を招くことなく安定よく行なわせることができるようになる。
【００１３】
この場合、運転制限手段は任意運転可となるまでアイドル回転速度に拘束するか、またはレギュレータの気化能力増大に応じてアイドル回転速度からこれよりも高い回転速度に拘束条件を変更し運転可能範囲を拡張する。
【００１４】
また、運転制限手段は運転者に視覚や聴覚でアクセル操作の可否を指示することにより混合気過濃とするような運転を行なわせないようにする。或いは絞り弁が電子制御されるものについては、アクセル操作にかかわらずエンジン回転速度を上昇させないように絞り弁を開かせない電子ガバナ機能を絞り弁アクチュエータ制御回路に組込むことにより、混合気過濃とする運転が不可能であるようにすることができる。
【００１５】
【発明の実施の形態】
図面を参照して本発明の実施の形態を説明すると、異なる実施の形態を示す図１，図３において、ボンベ１の液化ガス液相部分から延び電磁駆動の遮断弁３を有する送出管路２が図１のレギュレータ４の一次室５または図３のレギュレータ１４の熱交換室１５に接続されている。また、図１のレギュレータ４の二次室６から延びる供給管路８はエンジン１１の吸気管路１２に設置したミキサ９に接続され、図３のレギュレータ１４の圧力調整室１６から延びる供給管路１８はエンジン１１の吸気管路１２に設置した燃料噴射弁１９に接続されている。
【００１６】
図１のレギュレータ４はボンベ１から一次室５に送られてくる液化ガスを冷却水室７に導入したエンジン冷却水で加熱気化するとともに３０ｋＰａ程度の正圧に調整し、一次室５の正圧気化ガスを更に二次室６で大気圧程度に調整する周知のレギュレータ（ペーパライザ）であり、二次室６の気化ガスはミキサ９のベンチュリ９ａに発生する負圧に吸引されて吸気管路１２に送出される。
【００１７】
図３のレギュレータ１４はボンベ１から熱交換室１５に送られてくる液化ガスを冷却水室１７に導入したエンジン冷却水で加熱気化し、熱交換室１５でつくられた気化ガスを圧力調整室１６で３０ｋＰａ程度の所定正圧に調整する広く知られたレギュレータであり、圧力調整室１６の気化ガスは燃料噴射弁１９により吸気管路１２に送出される。
【００１８】
また、図１および図３の実施の形態において、エンジン冷却水の温度を検知する温度センサ３２がエンジン１１の冷却水ジャケット１１ａに設置されているとともに、液化ガスの温度および圧力を検知する温度センサ３３、圧力センサ３４がボンベ１に設置されている。尚、液化ガスの温度センサ３３はボンベ１の近傍に設置して間接的に検出させる場合があり、また圧力センサ３４は送出管路２に設置してもよい。そして、これらセンサ３２，３３，３４が検知した温度、圧力は電子式制御装置３１に入力される。
【００１９】
図１は絞り弁１０とアクセルペダル２１とがケーブル２２によって連結され、運転者のアクセルペダル２１踏込み操作に連動して絞り弁１０が機械的に開かれるものについての実施の形態を示している。
【００２０】
ここで、液化ガスとして一定組成のものを特定して使用する場合には、その組成の液化ガス蒸気圧、即ち或る温度、圧力における気化ガス生成量が一定であるので、エンジン冷却水の温度が判ればレギュレータ４で生成可能な気化ガス量を容易に求めることができる。
【００２１】
図２（Ａ）は使用する液化ガスが特定の一定組成のものとされていて液化ガスの温度センサ３３、圧力センサ３４を使用しない場合に運転制限を行なわせる手順を説明するブロック図であって、電子式制御装置３１は気化能力算定手段３５と任意運転可否判定手段３６とを有している。
【００２２】
気化能力算定手段３５は液化ガスの飽和蒸気圧、即ち或る圧力における温度に応じた気化ガス生成量、換言すればレギュレータ４の一次室５で生成可能な最大気化ガス量が記憶させてあり、温度センサ３２が検知したエンジン冷却水温度に基いてその温度で生成可能な最大気化ガス量を求める機能を有するものである。また、任意運転可否判定手段３６は或る回転速度でエンジン１１が要求する燃料流量、好ましくは全負荷時に要求する最大燃料流量が予め設定入力してあり、気化能力算定手段３５で求めた最大気化ガス量を設定してある要求燃料流量と比較し、この流量に達していないと判断したときは、生成可能な最大気化ガス量よりも要求燃料流量が少ない回転速度に運転を制限させる指令を運転制限手段３７に発するものである。
【００２３】
運転制限手段３７はアクセル操作の可否を運転者に報知するものであって、視覚により指示する画面を有する表示器３８と聴覚により指示するスピーカのような発声器３９とからなり、これらは例えば「アイドリング継続」、「アクセルペダル踏込み操作禁止」など運転を拘束する言葉を文字および音声によって運転者に知らせるものである。生成可能な最大気化ガス量が設定した要求燃料流量に達したときは表示器３８の画面を消すか、または「アクセルペダル踏込み可」、「自動車発進可」など任意運転を許可する言葉を文字および音声によって運転者に知らせる。また、任意運転を許可するまでアクセル操作を禁止することなく、生成可能な最大気化ガス量の増加に伴って「１，０００回転まで可」、「１，５００回転まで可」などエンジン回転速度の拘束条件を複数段階で順次高い回転速度に変更する機能を任意運転可否判定手段３６にもたせ、変更の都度運転制限手段３７で運転者に知らせるようにすることもできる。
【００２４】
図２（Ｂ）は使用する液化ガスの組成が不明または不定である場合に運転制限を行なわせる手段を説明するブロック図であって、この場合は図１に示す温度センサ３３、圧力センサ３４が使用され、且つ電子式制御装置３１に組成計算器４１、気化能力算出手段４２および任意運転可否判定手段３６を有している。
【００２５】
組成計算器４１には液化ガスの組成に応じた蒸気圧特性が予め入力記憶させてあり、温度センサ３３と圧力センサ３４が検知した液化ガスの温度とそのときの圧力とによって組成を特定することができる。従って、本実施の形態では温度センサ３３、圧力センサ３４および組成計算器４１が使用する液化ガスの組成を求める組成算出手段４０を構成している。
【００２６】
気化能力算出手段４２はエンジン冷却水温度に応じてレギュレータ４の一次室５で生成可能な最大気化ガス量が液化ガスの組成別に記憶させてあり、組成算出手段４０で求めた液化ガスの組成と温度センサ３２が検知したエンジン冷却水温度とに基いてその温度でレギュレータ４が生成可能な最大気化ガス量を求めるものである。任意運転可否判定手段３６は前述の機能を有し、またこれより発せられる指令を運転者に報知する表示器３８と発声器３９とからなる運転制限手段３７も前述の機能を有していて、これらは運転者によるアクセル操作の禁止、解除或いは拘束条件変更を行なうことも前述と同じである。
【００２７】
尚、運転制限手段３７は表示器３８と発声器３９のいずれか一方のみからなるものであってもよいが、これらを併用した場合は運転者への指示が更に確実に行なわれる、という利点がある。
【００２８】
次に、図３はアクセルペダル２１の踏込み量をアクセルペダル位置センサ２３で検知させ、絞り弁１０のアクチュエータである電動モータ２４を踏込み量に応じて駆動することにより絞り弁１０を開かせる絞り弁電子制御方式としたものについての実施の形態を示している。
【００２９】
図４（Ａ）は使用する液化ガスが特定の一定組成のものとされていて液化ガスの温度センサ３３、圧力センサ３４を使用しない場合に運転制限を行なわせる手段を説明するブロック図であって、電子式制御装置３１は気化能力算定手段３５、回転速度上限算出手段４３，任意運転可否決定手段４４、運転制限手段４５および制御器４６を有している。この気化能力算定手段３５は図２（Ａ）に示したものと同じであって、温度センサ３２が検知したエンジン冷却水温度に基いてその温度でレギュレータ１４の熱交換室１５が生成可能な最大気化ガス量を求めるものである。
【００３０】
回転速度上限算出手段４３はエンジン１１の回転速度と要求燃料流量との関係が予め入力記憶させてあり、気化能力算定手段３５で算出した最大気化ガス量で運転可能な回転速度の上限を算出するものである。任意運転可否決定手段４４はエンジン１１の或る回転速度、好ましくはエンジン１１がもつ最高回転速度を設定回転速度として予め入力記憶しておき、回転速度上限算出手段４３で算出した回転速度を設定回転速度と比較してこれよりも低いときは生成可能な最大気化ガス量よりも要求燃料流量が少ない回転速度に運転を制限させる指令を運転制限手段４５に発するものである。
【００３１】
制御器４６はアクセルペダル位置センサ２３からの信号に基いて、絞り弁１０にアクセルペダル２１の踏込み量に対応する開き動作を行なわせるようにステッピングモータまたは直流モータからなる電動モータ２４に駆動信号を送るものである。本実施の形態では、この制御器４６は電動モータ２４に送る駆動信号をアクセルペダル位置センサ２３からの信号と運転制限手段４５からの指示信号とのいずれかに基いたものとするように切換え可能としている。即ち、任意運転可否決定手段４４が運転を制限させる指令を発したとき、この指令を受けた運転制限手段４５はアクセルペダル位置センサ２３からの信号を遮断して予め設定した回転速度とする駆動信号を電動モータ２４に与えるように制御器４６に指示信号を発する。
【００３２】
制御器４６は運転制限手段３５からの指示信号を受けたとき、生成可能な最大気化ガス量が予め設定した回転速度の運転を可能とする量となるまでは、絞り弁１０をアイドル開度位置に固定しておくのが一般的である。しかし、生成可能な最大気化ガス量の増加に伴って運転制限手段３５の指示信号を変更し、絞り弁１０をアイドル開度位置からほぼ連続的に、或いは複数段階に分けて少しずつ開かせるように電動モータ２４に送る駆動信号を変更することもできる。レギュレータ１４で生成可能な最大気化ガス量が好ましくはエンジン１１がもつ最高回転速度とした設定回転速度での運転を可能とする量に達した後は運転制限手段４５から指示信号は発しなくなり、制御器４６はアクセルペダル２１の踏込み量に応じて絞り弁１０の開度を電子制御する本来の機能に戻る。
【００３３】
図４（Ｂ）は使用する液化ガスの組成が不明または不定である場合に運転制御を行なわせる手順を説明するブロック図であって、この場合は図３に示す温度センサ３３、圧力センサ３４が使用され、且つ電子式制御装置３１は組成計算器４１、気化能力算出手段４２、回転速度上限算出手段４３、任意運転可否決定手段４４、運転制限手段４５および制御器４６を具えている。
【００３４】
組成計算器４１は温度センサ３３と圧力センサ３４が検知した液化ガスの温度とそのときの圧力とによって組成を特定するものであり、これらは図２（Ｂ）について説明したのと同じ機能をもつ組成算出手段４０を構成する。また、気化能力算出手段４２は液化ガスの組成とエンジン冷却水の温度とに基いてレギュレータ１４が生成可能な最大気化ガス量を求めるものであり、図２（Ｂ）の気化能力算出手段４０と同じ機能をもっている。
【００３５】
更に、回転速度上限算出手段４３、任意運転可否決定手段４４、運転制限手段４５および制御器４６はいずれも図４（Ａ）のものと同じ機能を有している。
【００３６】
図３、図４（Ａ），（Ｂ）に示した実施の形態によると、絞り弁１０が電子制御されるものにおいて、レギュレータ１４が生成可能な最大気化ガス量で運転できる回転速度の上限が予め設定した回転速度に達しない間はアイドル回転速度に保持させるか、或いは生成可能な最大気化ガス量の増加に応じて回転速度を高い方に変更する電子ガバナ機能を持たせたことにより、アクセルペダル２１を踏込んでも回転速度を上昇させることなくエンジン１１に安定した暖機運転を行なわせることができる。生成可能な最大気化ガス量の増加に応じて回転速度を高くするファスト・アイドルを行なわせることは、暖機途中でのエンジン回転を確実に維持させるうえで有効である。
【００３７】
ここで、前述の電子がガバナが作用している時期にアクセルペダル２１を踏込んだとき、回転速度が上昇しないことによって運転者が故障と誤認する心配がある。このような誤認をさせないために、図２（Ａ），（Ｂ）に示した表示器３８や発声器３９と同様の報知手段４７を具えさせ、例えば任意運転可否決定手段４４からの信号に基いて「暖機待ち」、「運転待機」などアクセルペダル２１の踏込みを行なわせない指示を発するようにしている。
【００３８】
尚、図２（Ａ），（Ｂ）に示した電子式制御装置３１を図３の液化ガス燃料供給装置に適用し、電子ガバナ機能によることなく視覚や聴覚で運転者のアクセル操作を禁止させるようにすることができる。また、図２（Ａ），（Ｂ）に示した電子式制御装置３１における任意運転可否判定手段３６を図４（Ａ），（Ｂ）に示した電子式制御装置３１に用いた回転速度上限算出手段４３、任意運転可否決定手段４４に代えること、或いは図４（Ａ），（Ｂ）に示した電子式制御装置３１に用いた任意運転可否判定手段３６に代えることができる。
【００３９】
【発明の効果】
以上のように、エンジン冷却水温度に依存する液化ガスの気化能力が低い暖機途中において、視覚や聴覚或いは電子ガバナによりアクセル操作で気化能力を越える燃料流量を要求する回転速度に上昇させる運転を行なわせないようにしたことにより、暖機途中の運転をエンジン不調やエンジン停止、或いは再始動困難という不都合を招かずに安定よく行なうことができるものである。
【図面の簡単な説明】
【図１】本発明の実施の形態を示す配置図。
【図２】図１の形態について運転制限を行わせる異なる手順のブロック図。
【図３】本発明の異なる実施の形態を示す配置図。
【図４】図３の形態について運転制限を行わせる異なる手順のブロック図。
【符号の説明】
４，１４レギュレータ、９ミキサ、１０絞り弁、１１エンジン、１９燃料噴射弁、２１アクセルペダル、３１電子式制御装置、３２エンジン冷却水温度センサ、３５気化器能力算定手段、３６任意運転可否判定手段、
３７，４５運転制限手段、４０組成算出手段、４２気化能力算出手段、４３回転速度上限算出手段、４４任意運転可否決定手段[0001]
BACKGROUND OF THE INVENTION
The present invention comprises an apparatus for depressurizing and evaporating liquefied gas to a predetermined pressure and supplying it to an engine, more specifically, means for prohibiting an operation that requires an amount of fuel exceeding the liquefied gas evaporating capacity during a warm-up operation from a low temperature start, The present invention relates to a liquefied gas fuel supply device for an engine that can stably operate during warm-up.
[0002]
[Prior art]
A liquefied gas fuel supply device that sends liquefied gas in a cylinder to a suction pipe as vaporized gas whose pressure has been reduced to a predetermined pressure by a regulator and supplies the gas to the engine is well known, and the regulator heats and vaporizes the liquefied gas using engine cooling water. At the same time, the vaporized gas is adjusted to a predetermined pressure, that is, approximately atmospheric pressure, and sent to a mixer installed in the intake pipe, or is adjusted to a constant positive pressure and a fuel injection valve installed in the intake pipe is sent.
[0003]
For this reason, at the time of low temperature start-up when the temperature of the engine cooling water is low, only a small amount of liquefied gas can be vaporized until the warm-up progresses considerably. Ascending, for example, when driving an automobile, a part of the liquefied gas passes through the regulator without being vaporized and is sent to the intake pipe as a liquid, causing problems such as engine malfunction, engine stoppage, or difficulty in restart due to excessive mixture Produce.
[0004]
As a countermeasure, when the temperature of the engine cooling water is low, the vaporized gas is taken out from the gas phase portion in the cylinder and sent to the regulator, and when the temperature rises to some extent, the liquefied gas is taken out from the liquid phase portion to obtain the gas phase. JP-A-10-252569 and JP-A-11-257195 describe that the vaporized gas from the part is fed into the regulator. According to this measure, since the amount of the liquefied gas is small, it can be completely vaporized even with a low vaporization ability, and the engine speed can be increased without any problem in a state of insufficient warm-up.
[0005]
As another countermeasure, it is possible to equip a regulator with heating means using electric heat so that a considerable amount of liquefied gas can be vaporized even in a temperature range where vaporization capability is insufficient only with engine cooling water. No. 2223014 and Japanese Patent Application Laid-Open No. 11-324813, and even with this measure, it is possible to increase the engine rotation speed without any problem in an insufficient warm-up state.
[0006]
[Problems to be solved by the invention]
However, in actual engine operation, the driver can know the progress of warm-up with a water temperature gauge, but does not know the vaporization ability of the regulator at that time, so the engine rotation speed is increased beyond the vaporization ability. If this occurs, the liquefied gas is sent out to the intake pipe as a liquid, causing the above-mentioned disadvantages.
[0007]
The present invention relates to a liquefied gas fuel supply apparatus that heats and vaporizes liquefied gas with engine coolant using a regulator, adjusts the vaporized gas to a predetermined pressure, sends it to the intake pipe, and supplies it to the engine, immediately after starting at low temperature. In each of the countermeasures proposed to enable the engine speed to be increased when the engine is not warmed up, a fuel flow rate exceeding the vaporization capacity is required because the driver does not know the vaporization capacity of the regulator. In order to solve the above-mentioned problem that the operation to increase the rotation speed is unavoidable, and in such a case, the liquefied gas is sent to the intake pipe as a liquid and causes problems such as engine malfunction. The engine speed is limited so that the required fuel flow rate does not exceed the regulator's vaporization capability, and operation during warm-up is stabilized. An object of the present invention is to those that can be made to Ku done.
[0008]
[Means for Solving the Problems]
The present invention provides a vaporization capacity calculation means for obtaining a maximum vaporized gas amount that can be generated by a regulator based on the temperature of engine cooling water, and determines whether or not the calculated maximum vaporized gas amount has reached a predetermined engine required fuel flow rate. The first means for solving the above-described problem is provided with an arbitrary driving propriety determination means for performing the operation and an operation limiting means for limiting the engine rotation speed while the arbitrary driving propriety determination means is determined to be optional driving.
[0009]
Also, a composition calculating means for determining the composition of the liquefied gas, a vaporizing capacity calculating means for determining the maximum amount of vaporized gas that can be generated by the regulator based on the calculated composition of the liquefied gas and the temperature of the engine cooling water, and the calculated maximum vaporized gas Arbitrary operation propriety judging means for judging whether or not the amount has reached a predetermined engine required fuel flow rate, and an operation restricting means for restricting the engine rotation speed while the arbitrary operation feasibility judging means is in an arbitrary operation denial. It was set as the 2nd means for solving the said subject by having prepared.
[0010]
Alternatively, a vaporization capacity calculating means for obtaining the maximum vaporized gas amount that can be generated by the regulator based on the temperature of the engine cooling water, and a rotational speed upper limit calculating means for obtaining the engine maximum rotational speed that can be operated with the calculated maximum vaporized gas amount; Arbitrary driving propriety determining means for determining whether or not the maximum rotational speed obtained by the rotational speed upper limit calculating means has reached a preset rotational speed, and while the arbitrary driving propriety determining means is determined as optional driving or not, engine rotation By providing an operation limiting means for limiting the speed, a third means for solving the above-mentioned problems is provided.
[0011]
Alternatively, a composition calculating means for obtaining the composition of the liquefied gas, a vaporizing capacity calculating means for obtaining the maximum amount of vaporized gas that can be generated by the regulator based on the calculated composition of the liquefied gas and the temperature of the engine cooling water, and the calculated maximum vaporization Rotation speed upper limit calculation means for obtaining the maximum engine speed that can be operated with a gas amount, and optional driving determination for determining whether or not the maximum rotation speed obtained by the rotation speed upper limit calculation means has reached a preset rotation speed A fourth means for solving the above-described problem is provided with a means and an operation restricting means for restricting the engine rotation speed while the arbitrary operation propriety determining means determines whether or not the arbitrary operation is possible.
[0012]
Thus, according to the present invention in which the engine rotation speed is limited until the liquefied gas vaporization capability of the regulator depending on the engine coolant temperature is sufficient, an operation requiring a fuel flow rate exceeding the vaporization capability is performed. Therefore, the warm-up operation can be performed stably without causing the engine malfunction due to the rich mixture.
[0013]
In this case, the operation limiting means restricts the idle rotation speed until the arbitrary operation is possible, or changes the restriction condition from the idle rotation speed to a higher rotation speed in accordance with the increase in the vaporization capacity of the regulator, thereby reducing the operation range. Expand.
[0014]
Further, the driving restriction means prevents the driver from performing a driving operation that makes the air-fuel mixture rich by instructing the driver visually or audibly whether or not the accelerator operation is possible. Alternatively, if the throttle valve is electronically controlled, an electronic governor function that prevents the throttle valve from being opened so as not to increase the engine rotation speed regardless of the accelerator operation is incorporated into the throttle valve actuator control circuit. Driving can be impossible.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawings, an embodiment of the present invention will be described. In FIGS. 1 and 3 showing different embodiments, a delivery line 2 having an electromagnetically driven shut-off valve 3 extending from a liquefied gas liquid phase portion of a cylinder 1. Is connected to the primary chamber 5 of the regulator 4 of FIG. 1 or the heat exchange chamber 15 of the regulator 14 of FIG. Further, a supply line 8 extending from the secondary chamber 6 of the regulator 4 in FIG. 1 is connected to a mixer 9 installed in the intake line 12 of the engine 11, and a supply line extending from the pressure adjustment chamber 16 of the regulator 14 in FIG. 18 is connected to a fuel injection valve 19 installed in the intake pipe 12 of the engine 11.
[0016]
The regulator 4 in FIG. 1 heats and vaporizes the liquefied gas sent from the cylinder 1 to the primary chamber 5 with the engine coolant introduced into the cooling water chamber 7 and adjusts it to a positive pressure of about 30 kPa. This is a known regulator (paperizer) that further adjusts the vaporized gas to about atmospheric pressure in the secondary chamber 6. The vaporized gas in the secondary chamber 6 is sucked into the negative pressure generated in the venturi 9 a of the mixer 9 and is taken into the intake pipe 12. Is sent out.
[0017]
The regulator 14 in FIG. 3 heats and vaporizes the liquefied gas sent from the cylinder 1 to the heat exchange chamber 15 with the engine cooling water introduced into the cooling water chamber 17, and converts the vaporized gas produced in the heat exchange chamber 15 into the pressure adjustment chamber. 16 is a well-known regulator that adjusts the pressure to a predetermined positive pressure of about 30 kPa. The vaporized gas in the pressure adjustment chamber 16 is sent to the intake pipe 12 by the fuel injection valve 19.
[0018]
In the embodiment of FIGS. 1 and 3, a temperature sensor 32 for detecting the temperature of the engine cooling water is installed in the cooling water jacket 11a of the engine 11, and a temperature sensor for detecting the temperature and pressure of the liquefied gas. 33, a pressure sensor 34 is installed in the cylinder 1. The temperature sensor 33 of the liquefied gas may be installed in the vicinity of the cylinder 1 and indirectly detected, and the pressure sensor 34 may be installed in the delivery pipe 2. The temperature and pressure detected by these sensors 32, 33, and 34 are input to the electronic control device 31.
[0019]
FIG. 1 shows an embodiment in which a throttle valve 10 and an accelerator pedal 21 are connected by a cable 22 and the throttle valve 10 is mechanically opened in conjunction with a driver's operation of depressing the accelerator pedal 21.
[0020]
Here, when a specific composition of liquefied gas is used, the liquefied gas vapor pressure of the composition, that is, the amount of vaporized gas generated at a certain temperature and pressure is constant. Therefore, the amount of vaporized gas that can be generated by the regulator 4 can be easily obtained.
[0021]
FIG. 2A is a block diagram for explaining a procedure for restricting operation when the liquefied gas to be used has a specific constant composition and the liquefied gas temperature sensor 33 and pressure sensor 34 are not used. The electronic control device 31 has a vaporization capacity calculation means 35 and an optional operation availability determination means 36.
[0022]
The vaporization capacity calculating means 35 stores the saturated vapor pressure of the liquefied gas, that is, the vaporized gas generation amount corresponding to the temperature at a certain pressure, in other words, the maximum vaporized gas amount that can be generated in the primary chamber 5 of the regulator 4. Based on the engine coolant temperature detected by the temperature sensor 32, the maximum vaporized gas amount that can be generated at that temperature is obtained. The optional operation propriety judging means 36 is preset with the fuel flow rate required by the engine 11 at a certain rotational speed, preferably the maximum fuel flow required at full load, and the maximum vaporization obtained by the vaporization capacity calculating means 35. Compared with the required fuel flow rate that has set the gas amount, if it is determined that this flow rate has not been reached, a command is issued to limit the operation to a rotational speed at which the required fuel flow rate is less than the maximum vaporizable gas amount that can be generated. This is issued to the limiting means 37.
[0023]
The driving restriction means 37 notifies the driver of whether or not the accelerator operation is possible. The driving restricting means 37 includes a display 38 having a screen for visually instructing and a sounding device 39 such as a speaker for instructing by hearing. This is to inform the driver by words and voices of words that restrict driving such as “idling continuation” and “accelerator pedal depression operation prohibited”. When the maximum amount of vaporized gas that can be generated reaches the set required fuel flow rate, the screen of the display 38 is turned off, or words that permit arbitrary operation such as “accelerator pedal can be depressed” and “car start allowed” are written and Inform the driver by voice. In addition, without prohibiting the accelerator operation until the arbitrary operation is permitted, the engine speed of the engine such as “up to 1,000 rpm” or “up to 1,500 rpm” is increased as the maximum amount of vaporized gas that can be generated increases. It is also possible to give the arbitrary driving propriety determination means 36 the function of changing the constraint condition to a high rotational speed sequentially in a plurality of stages, and notify the driver by the driving restriction means 37 each time the change is made.
[0024]
FIG. 2B is a block diagram for explaining means for restricting the operation when the composition of the liquefied gas to be used is unknown or indefinite. In this case, the temperature sensor 33 and the pressure sensor 34 shown in FIG. The electronic control device 31 has a composition calculator 41, a vaporization capacity calculation means 42, and an arbitrary operation availability determination means 36.
[0025]
A vapor pressure characteristic corresponding to the composition of the liquefied gas is previously input and stored in the composition calculator 41, and the composition is specified by the temperature of the liquefied gas detected by the temperature sensor 33 and the pressure sensor 34 and the pressure at that time. Can do. Therefore, in the present embodiment, the composition calculation means 40 for obtaining the composition of the liquefied gas used by the temperature sensor 33, the pressure sensor 34, and the composition calculator 41 is configured.
[0026]
The vaporization capacity calculation means 42 stores the maximum vaporized gas amount that can be generated in the primary chamber 5 of the regulator 4 according to the engine coolant temperature for each composition of the liquefied gas, and the composition of the liquefied gas obtained by the composition calculation means 40 Based on the engine coolant temperature detected by the temperature sensor 32, the maximum amount of vaporized gas that can be generated by the regulator 4 at that temperature is obtained. The optional driving propriety judging means 36 has the above-mentioned function, and the driving restricting means 37 comprising a display 38 and a sounding device 39 for notifying the driver of a command issued therefrom also has the above-mentioned function. These are the same as described above for prohibiting or releasing the accelerator operation by the driver or changing the constraint conditions.
[0027]
The driving restriction means 37 may be composed of only one of the display 38 and the voice generator 39. However, when these are used in combination, there is an advantage that the instruction to the driver is more reliably performed. is there.
[0028]
Next, FIG. 3 shows a throttle valve that opens the throttle valve 10 by detecting the depression amount of the accelerator pedal 21 by the accelerator pedal position sensor 23 and driving the electric motor 24 that is an actuator of the throttle valve 10 according to the depression amount. An embodiment of an electronic control system is shown.
[0029]
FIG. 4A is a block diagram for explaining means for restricting operation when the liquefied gas to be used has a specific composition and the temperature sensor 33 and pressure sensor 34 of the liquefied gas are not used. The electronic control device 31 includes a vaporization capacity calculation means 35, a rotation speed upper limit calculation means 43, an arbitrary operation availability determination means 44, an operation restriction means 45, and a controller 46. This vaporization capacity calculation means 35 is the same as that shown in FIG. 2A, and is based on the engine coolant temperature detected by the temperature sensor 32 and is the maximum that the heat exchange chamber 15 of the regulator 14 can generate at that temperature. The amount of vaporized gas is obtained.
[0030]
The rotational speed upper limit calculating means 43 inputs and stores the relationship between the rotational speed of the engine 11 and the required fuel flow rate in advance, and calculates the upper limit of the rotational speed that can be operated with the maximum vaporized gas amount calculated by the vaporizing capacity calculating means 35. Is. Arbitrary driving propriety determination means 44 inputs and stores in advance a certain rotation speed of engine 11, preferably the maximum rotation speed of engine 11 as a set rotation speed, and sets the rotation speed calculated by rotation speed upper limit calculation means 43 as a set rotation. When the speed is lower than the speed, a command for limiting the operation to a rotational speed at which the required fuel flow rate is smaller than the maximum vaporized gas amount that can be generated is issued to the operation limiting means 45.
[0031]
Based on the signal from the accelerator pedal position sensor 23, the controller 46 sends a drive signal to the electric motor 24 comprising a stepping motor or a DC motor so that the throttle valve 10 performs an opening operation corresponding to the depression amount of the accelerator pedal 21. To send. In the present embodiment, the controller 46 can be switched so that the drive signal sent to the electric motor 24 is based on either the signal from the accelerator pedal position sensor 23 or the instruction signal from the operation restricting means 45. It is said. That is, when the arbitrary driving propriety determining means 44 issues a command to limit driving, the driving limiting means 45 that has received this command cuts off the signal from the accelerator pedal position sensor 23 and sets the driving speed to a preset rotational speed. Is sent to the controller 46 so as to give the electric motor 24.
[0032]
When the controller 46 receives the instruction signal from the operation limiting means 35, the throttle valve 10 is moved to the idle opening position until the maximum amount of vaporized gas that can be generated becomes an amount that enables operation at a preset rotational speed. Generally, it is fixed to. However, as the maximum amount of vaporized gas that can be generated increases, the instruction signal of the operation limiting means 35 is changed so that the throttle valve 10 is opened little by little almost continuously from the idle opening position or divided into a plurality of stages. The drive signal sent to the electric motor 24 can also be changed. After the maximum amount of vaporized gas that can be generated by the regulator 14 reaches an amount that enables operation at the set rotational speed, which is preferably the maximum rotational speed of the engine 11, an instruction signal is not issued from the operation restricting means 45 and control is performed. The device 46 returns to the original function of electronically controlling the opening degree of the throttle valve 10 in accordance with the depression amount of the accelerator pedal 21.
[0033]
FIG. 4B is a block diagram for explaining the procedure for controlling the operation when the composition of the liquefied gas to be used is unknown or indefinite. In this case, the temperature sensor 33 and the pressure sensor 34 shown in FIG. The electronic control device 31 used includes a composition calculator 41, a vaporization capacity calculation means 42, a rotation speed upper limit calculation means 43, an arbitrary operation availability determination means 44, an operation restriction means 45 and a controller 46.
[0034]
The composition calculator 41 specifies the composition based on the temperature of the liquefied gas detected by the temperature sensor 33 and the pressure sensor 34 and the pressure at that time, and these have the same function as described with reference to FIG. The composition calculation means 40 is configured. Further, the vaporization capacity calculation means 42 obtains the maximum vaporized gas amount that can be generated by the regulator 14 based on the composition of the liquefied gas and the temperature of the engine cooling water. The vaporization capacity calculation means 40 shown in FIG. Has the same function.
[0035]
Furthermore, the rotation speed upper limit calculation means 43, the arbitrary operation availability determination means 44, the operation restriction means 45, and the controller 46 all have the same functions as those in FIG.
[0036]
According to the embodiment shown in FIGS. 3, 4A, and 4B, in the case where the throttle valve 10 is electronically controlled, the upper limit of the rotational speed at which the regulator 14 can be operated with the maximum amount of vaporized gas that can be generated is set. The accelerator can be kept at the idle rotation speed while not reaching the preset rotation speed, or it has an electronic governor function that changes the rotation speed to a higher one in accordance with the increase in the maximum amount of vaporized gas that can be generated. Even if the pedal 21 is depressed, the engine 11 can be stably warmed up without increasing the rotational speed. Performing fast idling in which the rotational speed is increased in accordance with the increase in the maximum amount of vaporized gas that can be generated is effective for reliably maintaining engine rotation during warm-up.
[0037]
Here, when the accelerator pedal 21 is stepped on when the aforementioned governor is operating, there is a concern that the driver may misunderstand that the rotation speed does not increase. In order to prevent such a misidentification, the notification means 47 similar to the display 38 and the sound generator 39 shown in FIGS. 2A and 2B is provided, for example, based on a signal from the arbitrary driving availability determination means 44. Thus, an instruction not to depress the accelerator pedal 21 such as “waiting for warm-up” or “waiting for driving” is issued.
[0038]
The electronic control device 31 shown in FIGS. 2A and 2B is applied to the liquefied gas fuel supply device of FIG. 3, and the driver's accelerator operation is prohibited visually or audibly without using the electronic governor function. Can be. 2A and 2B, the arbitrary driving availability determination means 36 in the electronic control device 31 shown in FIGS. 2A and 2B is used in the electronic control device 31 shown in FIGS. 4A and 4B. It can replace with the calculation means 43 and the arbitrary driving | running | working availability determination means 44, or can be replaced with the arbitrary driving availability determination means 36 used for the electronic control apparatus 31 shown to FIG. 4 (A), (B).
[0039]
【The invention's effect】
As described above, in the middle of warming up, when the liquefied gas vaporization capacity that depends on the engine coolant temperature is low, the operation is performed to increase the fuel flow rate that exceeds the vaporization capacity by the accelerator operation by visual, auditory, or electronic governor. Since the operation is not performed, the operation during the warm-up can be performed stably without causing the inconvenience of engine malfunction, engine stop, or difficult restart.
[Brief description of the drawings]
FIG. 1 is a layout view showing an embodiment of the present invention.
FIG. 2 is a block diagram of a different procedure for restricting operation for the embodiment of FIG.
FIG. 3 is a layout view showing a different embodiment of the present invention.
4 is a block diagram of different procedures for restricting operation for the embodiment of FIG.
[Explanation of symbols]
4,14 Regulator, 9 Mixer, 10 Throttle valve, 11 Engine, 19 Fuel injection valve, 21 Accelerator pedal, 31 Electronic control device, 32 Engine coolant temperature sensor, 35 Vaporizer capacity calculation means, 36 Arbitrary operation availability determination means ,
37, 45 operation restriction means, 40 composition calculation means, 42 vaporization capacity calculation means, 43 rotation speed upper limit calculation means, 44 arbitrary operation availability determination means

Claims

In the liquefied gas fuel supply apparatus, the liquefied gas is heated and vaporized by the engine cooling water with a regulator, adjusted to a vaporized gas of a predetermined pressure, sent to the intake pipe, and supplied to the engine.
Vaporization capacity calculation means for determining the maximum amount of vaporized gas that can be generated by the regulator based on the temperature of the engine cooling water, and an option for determining whether or not the calculated maximum vaporized gas amount has reached a preset engine required fuel flow rate A driving restriction unit for limiting engine rotation speed while the driving permission determination unit and the arbitrary driving permission determination unit determine that the arbitrary driving is prohibited;
An liquefied gas fuel supply device for an engine characterized by comprising:

In the liquefied gas fuel supply apparatus, the liquefied gas is heated and vaporized by the engine cooling water with a regulator, adjusted to a vaporized gas of a predetermined pressure, sent to the intake pipe, and supplied to the engine.
Composition calculating means for obtaining the composition of the liquefied gas, vaporization capacity calculating means for obtaining the maximum amount of vaporized gas that can be generated by the regulator based on the calculated composition of the liquefied gas and the temperature of the engine cooling water, and the calculated maximum amount of vaporized gas Optional driving propriety determination means for determining whether or not the engine required fuel flow rate has been set in advance, and operation limiting means for limiting the engine rotation speed while the arbitrary driving propriety determination means is optional driving,
An liquefied gas fuel supply device for an engine characterized by comprising:

3. The liquefied gas fuel supply device for an engine according to claim 1, wherein an engine required fuel flow rate set in the arbitrary operation availability determination unit is an engine required maximum fuel flow rate. 4.

In the liquefied gas fuel supply apparatus, the liquefied gas is heated and vaporized by the engine cooling water with a regulator, adjusted to a vaporized gas of a predetermined pressure, sent to the intake pipe, and supplied to the engine.
A vaporization capacity calculating means for obtaining a maximum vaporized gas amount that can be generated by the regulator based on a temperature of engine cooling water; a rotational speed upper limit calculating means for obtaining an engine maximum rotational speed operable with the calculated maximum vaporized gas amount; Arbitrary operation propriety determining means for determining whether or not the maximum rotational speed obtained by the rotational speed upper limit calculating means has reached a preset rotational speed, and while the arbitrary operation propriety determining means is determined as optional operation rejection, the engine rotational speed Operation restriction means for restricting,
An liquefied gas fuel supply device for an engine characterized by comprising:

In the liquefied gas fuel supply device for supplying the liquefied gas to the engine which is heated and vaporized by the engine cooling water with a regulator and adjusted to the vaporized gas of a predetermined pressure and sent to the intake pipe,
Composition calculating means for obtaining the composition of the liquefied gas, vaporization capacity calculating means for obtaining the maximum amount of vaporized gas that can be generated by the regulator based on the calculated composition of the liquefied gas and the temperature of the engine cooling water, and the calculated maximum amount of vaporized gas A rotational speed upper limit calculating means for obtaining the engine maximum rotational speed that can be operated by the engine, and an arbitrary operation propriety determining means for determining whether or not the maximum rotational speed obtained by the rotational speed upper limit calculating means has reached a preset rotational speed; An operation limiting means for limiting the engine rotation speed while the arbitrary driving propriety determining means determines that the arbitrary driving is prohibited,
An liquefied gas fuel supply device for an engine characterized by comprising:

6. The liquefied gas fuel supply of an engine according to claim 1, wherein the operation restricting means is set so as to restrain the engine to an idle rotation speed until the arbitrary operation enable / disable determining means enables arbitrary operation. apparatus.

When the arbitrary operation propriety determination / determination unit determines that the arbitrary operation is not permitted, the constraint condition of the engine rotation speed is determined from the idle rotation speed according to the increase in the maximum vaporized gas amount calculated or calculated by the vaporization capacity calculation or calculation unit. 6. The liquefied gas fuel supply device for an engine according to claim 1, wherein the engine speed is changed to a higher rotational speed.

6. The liquefied gas fuel supply device for an engine according to claim 1, wherein the operation restricting means instructs the driver whether or not the accelerator operation is possible visually or / and audibly.

In the case where the throttle valve installed in the intake pipe is electronically controlled, the operation restriction means fixes the throttle valve at an idle opening regardless of the driver's accelerator operation, or the maximum vaporization that can be generated by the regulator The liquefied gas fuel supply device for an engine according to claim 1, 2, 4, or 5, which is an electronic governor that opens the throttle valve in accordance with an increase in gas amount.

In the case where the throttle valve installed in the intake pipe is electronically controlled, the operation restriction means responds to an increase in the maximum amount of vaporized gas that can be generated by the regulator regardless of the driver's accelerator operation. The liquefied gas fuel supply device for an engine according to claim 1, 2, 4, or 5, which is an electronic governor to be opened.

11. The liquefied gas fuel supply device for an engine according to claim 9 or 10, further comprising notifying means for notifying a driver that the electronic governor restricts opening of the throttle valve.