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JP2004360632A - Fuel pressure rise prevention device for lpg injection type engine - Google Patents

Fuel pressure rise prevention device for lpg injection type engine Download PDF

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Publication number
JP2004360632A
JP2004360632A JP2003162131A JP2003162131A JP2004360632A JP 2004360632 A JP2004360632 A JP 2004360632A JP 2003162131 A JP2003162131 A JP 2003162131A JP 2003162131 A JP2003162131 A JP 2003162131A JP 2004360632 A JP2004360632 A JP 2004360632A
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Japan
Prior art keywords
lpg
pressure
fuel
passage
valve
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JP2003162131A
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JP4300308B2 (en
Inventor
Shuji Tanaka
周治 田中
Kazuo Nakatani
和生 中谷
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Nissan Kohki Co Ltd
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Nissan Kohki Co Ltd
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Priority to JP2003162131A priority Critical patent/JP4300308B2/en
Priority to US10/861,641 priority patent/US6988489B2/en
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/30—Use of alternative fuels, e.g. biofuels

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  • Combined Controls Of Internal Combustion Engines (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel pressure rise prevention device for a LPG injection type engine capable of avoiding failures of components, such as a fuel pressure sensor, and an engine malfunction by automatically releasing the pressure of LPG even if the LPG pressure becomes abnormally high at the failure of a vaporizer. <P>SOLUTION: Relief valves 7<SB>1</SB>, 7<SB>2</SB>opening valve ports by a set pressure difference are connected in parallel between a LPG passage 6 and an intake manifold 2. When differential pressure between the LPG passage 6 and the intake manifold 2 reaches set pressure, the relief valves 7<SB>1</SB>, 7<SB>2</SB>are opened sequentially in accordance with the set pressure, and LPG in the LPG passage 6 is directly exhausted to the inside of the intake manifold 2. A LPG fuel shutoff valve 9 is provided on a LPG passage 8, and a LPG fuel pressure sensor 10 is provided on the LPG passage 6. When gas pressure on the LPG passage 6 exceeds set pressure, the LPG fuel shutoff valve 9 is shut off, and LPG fuel supplied from a LPG steel cylinder is forcibly shut off. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、ＬＰＧ噴射式エンジンにおけるＬＰＧ燃料供給経路の燃圧上昇防止装置に関する。
【０００２】
【従来の技術】
ＬＰＧ噴射式エンジンにおいて、液体ＬＰＧを気化するベーパライザーが故障した場合などにおいては、ＬＰＧ燃料噴射弁にかかる圧力が異常に高くなる可能性がある。従来のＬＰＧ噴射式エンジンでは、このような圧力上昇を抑制する機構や装置が存在しないため、このような圧力上昇が発生すると、圧力センサーなどの部品が故障したり、エンジン不調を来す恐れがあった。
【０００３】
例えば、特許文献１には、水素ガスなどを用いた気体燃料エンジンにおいて、エンジン始動不良時やエンスト時のエンジン停止直前における不適正な気体燃料の供給によるアフターバーンやバックファイアを防止するため、燃料通路中の流量調整弁の下流側にＬＰＧ燃料遮断弁を設け、吸気マニホールドのベンチュリなどで吸気状態を検出し、エンジン停止前にＬＰＧ燃料遮断弁を閉じるようにした技術が示されているが、この技術はエンジン始動不良時やエンスト時のアフターバーンやバックファイアを防止するためのものであり、本発明が目的とするＬＰＧ燃料の燃圧上昇とは関係がなく、ベーパライザー故障時などにおける燃圧上昇を自動的に抑制するものではない。
【０００４】
【特許文献１】
特開平５−２１４９３７号号公報（全頁、全図）
【０００５】
【発明が解決しようとする課題】
本発明は、液体ＬＰＧを気化するベーパライザーが故障した場合などに燃料噴射弁にかかるＬＰＧガスの圧力が異常に高くなっても、これを自動的に解放して燃圧センサーなどの部品故障やエンジン不調を回避することのできるＬＰＧ噴射式エンジンの燃圧上昇防止装置を提供することを課題とするものである。
【０００６】
【課題を解決するための手段】
上記課題を解決するため、本発明では次のような手段を採用した。
すなわち、請求項１に記載の燃圧上昇防止装置は、ＬＰＧボンベから送給される液化ＬＰＧをベーパライザーで気化して所定圧力のＬＰＧガスに変換し、ＬＰＧ燃料噴射弁から吸気マニホールド内へ噴射するようにしたＬＰＧ噴射式エンジンにおいて、前記ベーパライザーとＬＰＧ燃料噴射弁との間をむすぶＬＰＧ通路と、前記吸気マニホールドとの間に、設定差圧で弁口を開くリリーフ弁を接続し、前記ＬＰＧ通路と吸気マニホールド間の圧力差が設定圧に達したとき、前記リリーフ弁の弁口を自動的に開き、ＬＰＧ通路のＬＰＧガスを吸気マニホールド内へ直接排出するようにしたことものである。このような構成とした場合、ベーパライザーとＬＰＧ燃料噴射弁との間をむすぶＬＰＧ通路のガス圧の異常上昇発生時、リリーフ弁によってＬＰＧガスを直接吸気マニホールド内へ排出することができ、ガス圧の異常上昇を抑制することができる。
【０００７】
請求項２に記載の燃圧上昇防止装置は、上記請求項１に記載の燃圧上昇防止装置において、前記リリーフ弁を並列に複数個設け、各リリーフ弁の作動圧力を段階的に変えたものである。このような構成とした場合、ガス圧の異常上昇を段階的に解放しながら抑制することができ、よりきめ細かな制御を実現することができる。
【０００８】
請求項３に記載の燃圧上昇防止装置は、前記請求項１または２に記載の燃圧上昇防止装置において、前記ＬＰＧボンベとベーパライザーとの間を結ぶ液化ＬＰＧ通路にＬＰＧ燃料遮断弁を設けるとともに、前記ベーパライザーとＬＰＧ燃料噴射弁との間をむすぶＬＰＧ通路にはＬＰＧ燃圧センサーを設け、前記ＬＰＧ通路の圧力が設定圧力以上になったことをＬＰＧ燃圧センサーが検出したときに前記ＬＰＧ燃料遮断弁を作動し、ＬＰＧボンベからベーパライザーに送給されるＬＰＧ燃料を強制的に遮断するようにしたものである。このような構成とした場合、ＬＰＧ燃料の供給を自動的に遮断し、燃圧上昇を更に抑えることができる。
【０００９】
【発明の実施の形態】
以下、本発明の実施の形態について図面を参照して説明する。
図１に、本発明に係る燃圧上昇防止装置の一実施の形態を示す。図において、１は液化ＬＰＧの入ったＬＰＧボンベ、２はＬＰＧ燃料式エンジンにつながる吸気マニホールドであって、吸気マニホールド２の適宜位置には、ＬＰＧ燃料を供給するためのＬＰＧ燃料噴射弁３が設けられている。
【００１０】
ＬＰＧボンベ１とＬＰＧ燃料噴射弁３との間には、ベーパライザー４が設けられており、ＬＰＧボンベ１から送給されてくる高圧（例えば約１８ｋｇｆ／ｃｍ２）の液化ＬＰＧを所定圧力（例えば０．３Ｋｇｆ／ｃｍ２前後）のＬＰＧガスに変換し、電子制御装置（ＥＣＭ）５の制御の下、所定のタイミングでＬＰＧ燃料噴射弁３から吸気マニホールド２内に噴射するように構成されている。
【００１１】
前記ＬＰＧボンベ１、ベーパライザー４、ＬＰＧ燃料噴射弁３、電子制御装置５からなる機構は、ＬＰＧ燃料式エンジンにおける公知の燃料供給系を構成している。本発明は、この従来公知のＬＰＧ燃料供給系において、次のような機構を付加することにより、ベーパライザー４から送り出されるＬＰＧガスの圧力が異常上昇した際に、その圧力上昇に応じて段階的にＬＰＧガスを吸気マニホールド２内へ直接排出し、異常なガス圧を解放するようにしたものである。
【００１２】
すなわち、本発明は、ベーパライザー４とＬＰＧ燃料噴射弁３との間を結ぶＬＰＧ通路６の途中に２つのリリーフ弁７１，７２をＬＰＧ燃料噴射弁３に対して並列に設け、その出口側を吸気マニホールド２に直接臨ませたものである。この２つのリリーフ弁７１，７２は、ＬＰＧ通路６内のＬＰＧガス圧と吸気マニホールド２内の圧力との差圧で作動するメカニカル弁であって、例えば、第１のリリーフ弁７１は、差圧０．８Ｋｇｆ／ｃｍ２で作動するように設定され、第２のリリーフ弁７２は、差圧１．２Ｋｇｆ／ｃｍ２で作動するように設定されている。なお、図示例では、２つのリリーフ弁７１，７２をそれぞれ独立に設けたが、いずれか一方または両方を燃料噴射弁３内に一体に組み込んでもよい。
【００１３】
さらに、本発明では、許容範囲を超える異常圧力が発生した時に、ＬＰＧ燃料の送給そのものを停止させるために、ＬＰＧボンベ１とベーパライザー４との間をむすぶ液化ＬＰＧ通路８の途中にＬＰＧ燃料遮断弁９を設けるとともに、ＬＰＧ通路６には、ＬＰＧ通路６内のガス圧を常時監視するＬＰＧ燃圧センサー１０を設けた。また、警告灯１１を設け、許容範囲を超える異常圧力発生時、電子制御装置５によって警告灯１１を点灯し、異常を知らせるように構成した。なお、ＬＰＧ燃圧センサー１０は、本発明専用のものを独立に設けてもよいが、エンジン制御のためにＬＰＧ通路６に従前から備えられているガス圧センサーを前記ＬＰＧ燃圧センサー１０として兼用し、その検出信号を異常検知に利用するようにしてもよい。
【００１４】
上記構成になる燃圧上昇防止装置は、次のように作動する。
まず、ベーパライザー４からＬＰＧ燃料噴射弁３に供給されるＬＰＧガスのガス圧が正常範囲にある場合、２つのリリーフ弁７１，７２ とＬＰＧ燃料遮断弁９は作動することがなく、ベーパライザー４からＬＰＧ燃料噴射弁３に向けて送給されたＬＰＧガスは、電子制御装置５の制御の下、ＬＰＧ通路６を通じてＬＰＧ燃料遮断弁９から吸気マニホールド２内へ噴射される。
【００１５】
いま、ベーパライザー４に何らかの故障が発生し、ＬＰＧ通路６内のガス圧が上昇し、第１のリリーフ弁７１の設定圧０．８Ｋｇｆ／ｃｍ２に達すると、第１のリリーフ弁７１が作動し、その弁口を開く。第１のリリーフ弁７１の弁口が開くと、異常圧状態にあるＬＰＧ通路６内のＬＰＧガスは、ＬＰＧ燃料噴射弁３を迂回して、第１のリリーフ弁７１から直接吸気マニホールド２内へ排出される。この結果、ＬＰＧ通路６内のＬＰＧガスの異常圧力上昇が抑えられ、ガス圧異常に伴う燃圧センサーなどの部品故障やエンジン不調を自動的に回避することができる。
【００１６】
ＬＰＧ通路６内のガス圧がさらに上昇していき、前記第１のリリーフ弁７１だけでは圧力上昇を充分に抑えることができない場合には、ＬＰＧガスの圧力が第２のリリーフ弁７２の設定圧１．２Ｋｇｆ／ｃｍ２に達した時点で、第２のリリーフ弁７２が作動し、その弁口を開く。この結果、第１のリリーフ弁７１と第２のリリーフ弁７２の２つの弁によってＬＰＧガスが吸気マニホールド２内へ直接排出される。このため、ＬＰＧガスの圧力上昇を確実に抑えることができるようになる。
【００１７】
一方、ＬＰＧ通路６内のガス圧をＬＰＧ燃圧センサー１０で検出し、電子制御装置５によって常時監視しているので、前記第１のリリーフ弁７１と第２のリリーフ弁７２の２つが作動したにもかかわらず、ＬＰＧガスの圧力がさらに上昇していくような場合には、電子制御装置５がその圧力変動から許容範囲を超える異常発生と診断し、ＬＰＧボンベ１とベーパライザー４をむすぶ液化ＬＰＧ通路８に設けられているＬＰＧ燃料遮断弁９を作動し、液化ＬＰＧ通路８を強制的に遮断する。これによって、ＬＰＧ燃料自体の送給が強制的に停止され、圧力上昇を更に抑えることができる。また、これと同時に、電子制御装置５は警告灯１１を点灯し、圧力異常の発生を知らせる。
【００１８】
なお、前記実施の形態では、リリーフ弁を２個設けた場合を例に採って説明したが、リリーフ弁は２個だけに限らず、３個以上設けてもよいし、場合によっては１個だけでもよい。一般的に、リリーフ弁の数が多いほど、異常圧力の抑制作用をきめ細かく行なうことが可能となる。
【００１９】
【発明の効果】
以上説明したように、請求項１に記載の発明によれば、ＬＰＧ通路と吸気マニホールド間の圧力差が設定圧に達したとき、リリーフ弁の弁口を自動的に開き、ＬＰＧ通路のＬＰＧガスを吸気マニホールド内へ直接排出するようにしたので、ＬＰＧガスの圧力異常に伴う燃圧センサーなどの部品故障やエンジン不調を自動的に回避することができる。
【００２０】
請求項２に記載の発明によれば、リリーフ弁を複数個並列に設け、各リリーフ弁の設定差圧を段階的に変えるようにしたので、圧力上昇に従ってリリーフ弁を順番に開口していくことができ、よりきめ細かな圧力抑制を行なうことができる。
【００２１】
請求項３に記載の発明によれば、ＬＰＧ通路の圧力が設定圧力以上になったことをＬＰＧ燃圧センサーで検出したときにＬＰＧ燃料遮断弁を作動し、ＬＰＧボンベからベーパライザーに送給されるＬＰＧ燃料を強制的に遮断するようにしたので、自動的にＬＰＧ燃料の供給を停止し、燃圧上昇を更に抑えることができる。
【図面の簡単な説明】
【図１】本発明にかかる燃圧上昇防止装置の一実施の形態を示すブロック図である。
【符号の説明】
１ ＬＰＧボンベ
２ 吸気マニホールド
３ ＬＰＧ燃料噴射弁
４ ベーパライザー
５ 電子制御装置（ＥＣＭ）
６ ＬＰＧ通路
７１，７２ リリーフ弁
８ 液化ＬＰＧ通路
９ ＬＰＧ燃料遮断弁
１０ ＬＰＧ燃圧センサー
１１ 警告灯[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel pressure rise prevention device for an LPG fuel supply path in an LPG injection engine.
[0002]
[Prior art]
In the LPG injection engine, when the vaporizer for vaporizing the liquid LPG breaks down, the pressure applied to the LPG fuel injection valve may become abnormally high. In a conventional LPG injection engine, there is no mechanism or device for suppressing such a rise in pressure. Therefore, if such a rise in pressure occurs, there is a risk that components such as the pressure sensor may fail or the engine may malfunction. there were.
[0003]
For example, in Patent Document 1, in a gaseous fuel engine using hydrogen gas or the like, in order to prevent afterburn or backfire due to improper supply of gaseous fuel immediately before the engine is stopped at the time of engine start failure or engine stall, the fuel is used. There is disclosed a technology in which an LPG fuel cutoff valve is provided downstream of a flow control valve in a passage, an intake state is detected by a venturi of an intake manifold or the like, and the LPG fuel cutoff valve is closed before the engine stops. This technology is to prevent afterburn and backfire at the time of engine start failure or engine stall. It is not related to the increase of the fuel pressure of LPG fuel, which is the purpose of the present invention. Is not automatically suppressed.
[0004]
[Patent Document 1]
JP-A-5-214937 (all pages, all drawings)
[0005]
[Problems to be solved by the invention]
According to the present invention, even if the pressure of the LPG gas applied to the fuel injection valve becomes abnormally high when, for example, the vaporizer for vaporizing the liquid LPG fails, the pressure is automatically released to cause a component failure such as a fuel pressure sensor or an engine failure. It is an object of the present invention to provide a fuel pressure rise prevention device for an LPG injection engine that can avoid malfunction.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present invention employs the following means.
That is, in the fuel pressure rise prevention device according to the first aspect, the liquefied LPG supplied from the LPG cylinder is vaporized by the vaporizer, converted into LPG gas at a predetermined pressure, and injected from the LPG fuel injection valve into the intake manifold. In the above LPG injection engine, a relief valve for opening a valve port at a set differential pressure is connected between the LPG passage connecting the vaporizer and the LPG fuel injection valve and the intake manifold, When the pressure difference between the passage and the intake manifold reaches a set pressure, the valve opening of the relief valve is automatically opened, and the LPG gas in the LPG passage is directly discharged into the intake manifold. With such a configuration, when an abnormal increase in the gas pressure in the LPG passage between the vaporizer and the LPG fuel injection valve occurs, the LPG gas can be directly discharged into the intake manifold by the relief valve. Abnormal rise can be suppressed.
[0007]
According to a second aspect of the present invention, in the fuel pressure rise preventing device according to the first aspect, a plurality of the relief valves are provided in parallel, and the operating pressure of each relief valve is changed stepwise. . In the case of such a configuration, an abnormal increase in the gas pressure can be suppressed while being released in a stepwise manner, and more detailed control can be realized.
[0008]
The fuel pressure rise preventing device according to claim 3 is the fuel pressure rise preventing device according to claim 1 or 2, wherein an LPG fuel cutoff valve is provided in a liquefied LPG passage connecting between the LPG cylinder and a vaporizer, An LPG fuel pressure sensor is provided in an LPG passage connecting between the vaporizer and the LPG fuel injection valve, and the LPG fuel cutoff valve is provided when the LPG fuel pressure sensor detects that the pressure in the LPG passage has exceeded a set pressure. Is operated to forcibly shut off the LPG fuel sent from the LPG cylinder to the vaporizer. In the case of such a configuration, the supply of the LPG fuel is automatically cut off, and the increase in the fuel pressure can be further suppressed.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an embodiment of a fuel pressure rise prevention device according to the present invention. In the figure, 1 is an LPG cylinder containing liquefied LPG, 2 is an intake manifold connected to an LPG fuel type engine, and an LPG fuel injection valve 3 for supplying LPG fuel is provided at an appropriate position of the intake manifold 2. Have been.
[0010]
A vaporizer 4 is provided between the LPG cylinder 1 and the LPG fuel injection valve 3 to convert a high-pressure (for example, about 18 kgf / cm 2 ) liquefied LPG supplied from the LPG cylinder 1 to a predetermined pressure (for example, The LPG gas is converted into LPG gas of about 0.3 kgf / cm 2 ) and is injected from the LPG fuel injection valve 3 into the intake manifold 2 at a predetermined timing under the control of the electronic control unit (ECM) 5. .
[0011]
The mechanism including the LPG cylinder 1, the vaporizer 4, the LPG fuel injection valve 3, and the electronic control unit 5 constitutes a known fuel supply system in the LPG fuel type engine. According to the present invention, when the pressure of the LPG gas sent from the vaporizer 4 rises abnormally by adding the following mechanism to this conventionally known LPG fuel supply system, The LPG gas is directly discharged into the intake manifold 2 to release an abnormal gas pressure.
[0012]
That is, the present invention is provided in parallel to the vaporizer 4 and the middle two of the relief valve of the LPG passage 6 connecting between the LPG fuel injection valve 3 7 1, 7 2 LPG fuel injection valves 3, the outlet The side faces directly to the intake manifold 2. The two relief valves 7 1, 7 2 is a mechanical valve that operates in the differential pressure between the LPG gas pressure in the LPG passage 6 and the pressure in the intake manifold 2, for example, the first relief valve 71 is , it is set to operate at a differential pressure 0.8 kgf / cm 2, a second relief valve 7 2 is set to operate at a differential pressure 1.2 kgf / cm 2. In the illustrated example, two of the relief valve 7 1, 7 2 are provided independently, may be incorporated integrally in either or both the fuel injection valve 3.
[0013]
Further, in the present invention, when an abnormal pressure exceeding an allowable range is generated, the LPG fuel is stopped in the middle of the liquefied LPG passage 8 between the LPG cylinder 1 and the vaporizer 4 in order to stop the supply of the LPG fuel itself. In addition to providing the shutoff valve 9, the LPG passage 6 is provided with an LPG fuel pressure sensor 10 for constantly monitoring the gas pressure in the LPG passage 6. Also, a warning light 11 is provided, and when an abnormal pressure exceeding an allowable range occurs, the electronic control unit 5 turns on the warning light 11 to notify the abnormality. Although the LPG fuel pressure sensor 10 may be provided independently for the present invention, a gas pressure sensor provided in front of the LPG passage 6 for engine control is also used as the LPG fuel pressure sensor 10, The detection signal may be used for abnormality detection.
[0014]
The fuel pressure rise prevention device configured as described above operates as follows.
First, when the gas pressure of the LPG gas supplied from vaporizer 4 in LPG fuel injection valve 3 is in the normal range, the two relief valves 7 1, 7 2 and LPG fuel shut-off valve 9 is not able to operate, vapor The LPG gas sent from the riser 4 toward the LPG fuel injection valve 3 is injected from the LPG fuel cutoff valve 9 into the intake manifold 2 through the LPG passage 6 under the control of the electronic control unit 5.
[0015]
Now, any failure occurs in vaporizer 4, the gas pressure in the LPG passage 6 rises and first reaches the set pressure 0.8 kgf / cm 2 of the relief valve 7 1, the first relief valve 7 1 Operates and opens its valve port. When the first relief valve 71 of the valve port open, LPG gas LPG passage 6 in the abnormal pressure condition, bypassing the LPG fuel injection valve 3, the first direct intake manifold from the relief valve 7 1 2 It is discharged inside. As a result, an abnormal increase in the pressure of the LPG gas in the LPG passage 6 is suppressed, and it is possible to automatically avoid failure of components such as a fuel pressure sensor and malfunction of the engine due to abnormal gas pressure.
[0016]
Soars gas pressure LPG passage 6 further wherein first only the relief valve 71 if it can not be sufficiently suppressed increase in pressure, the pressure of the LPG gas in the second relief valve 7 2 Once at the set pressure 1.2 kgf / cm 2, a second relief valve 7 2 is operated to open the valve port. As a result, LPG gas is discharged directly into the intake manifold 2 by the first relief valve 7 1 and the second of the two valves of the relief valve 7 2. For this reason, an increase in the pressure of the LPG gas can be reliably suppressed.
[0017]
On the other hand, to detect the gas pressure in the LPG passage 6 in LPG fuel pressure sensor 10, since the monitored constantly by the electronic control unit 5, the first relief valve 7 1 and the second relief valve 7 2 two are working If the pressure of the LPG gas further rises despite this, the electronic control unit 5 diagnoses the occurrence of an abnormality exceeding an allowable range from the pressure fluctuation, and connects the LPG cylinder 1 and the vaporizer 4. The liquefied LPG passage 8 is forcibly shut off by operating the LPG fuel cutoff valve 9 provided in the liquefied LPG passage 8. As a result, the supply of the LPG fuel itself is forcibly stopped, and the pressure rise can be further suppressed. At the same time, the electronic control unit 5 turns on the warning light 11 to notify the occurrence of a pressure abnormality.
[0018]
In the above embodiment, the case where two relief valves are provided has been described as an example. However, the number of relief valves is not limited to two, and three or more relief valves may be provided. May be. In general, the greater the number of relief valves, the finer the effect of suppressing abnormal pressure can be performed.
[0019]
【The invention's effect】
As described above, according to the first aspect of the invention, when the pressure difference between the LPG passage and the intake manifold reaches the set pressure, the valve opening of the relief valve is automatically opened, and the LPG gas in the LPG passage is opened. Is directly discharged into the intake manifold, it is possible to automatically avoid failure of components such as a fuel pressure sensor due to abnormal LPG gas pressure and malfunction of the engine.
[0020]
According to the second aspect of the present invention, since a plurality of relief valves are provided in parallel and the set differential pressure of each relief valve is changed in a stepwise manner, the relief valves are sequentially opened according to the pressure rise. And finer pressure suppression can be performed.
[0021]
According to the third aspect of the present invention, when the LPG fuel pressure sensor detects that the pressure of the LPG passage has become equal to or higher than the set pressure, the LPG fuel cutoff valve is operated, and the LPG cylinder is supplied to the vaporizer. Since the LPG fuel is forcibly shut off, the supply of the LPG fuel is automatically stopped, and the rise in fuel pressure can be further suppressed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of a fuel pressure rise prevention device according to the present invention.
[Explanation of symbols]
1 LPG cylinder 2 Intake manifold 3 LPG fuel injection valve 4 Vaporizer 5 Electronic control unit (ECM)
6 LPG passage 7 1 , 7 2 Relief valve 8 Liquefied LPG passage 9 LPG fuel cutoff valve 10 LPG fuel pressure sensor 11 Warning light

Claims (3)

ＬＰＧボンベから送給される液化ＬＰＧをベーパライザーで気化して所定圧力のＬＰＧガスに変換し、ＬＰＧ燃料噴射弁から吸気マニホールド内へ噴射するようにしたＬＰＧ噴射式エンジンにおいて、
前記ベーパライザーとＬＰＧ燃料噴射弁との間をむすぶＬＰＧ通路と、前記吸気マニホールドとの間に、設定差圧で弁口を開くリリーフ弁を接続し、
前記ＬＰＧ通路と吸気マニホールド間の圧力差が設定圧に達したとき、前記リリーフ弁の弁口を自動的に開き、ＬＰＧ通路のＬＰＧガスを吸気マニホールド内へ直接排出するようにしたことを特徴とするＬＰＧ噴射式エンジンの燃圧上昇防止装置。In an LPG injection engine, a liquefied LPG supplied from an LPG cylinder is vaporized by a vaporizer, converted into LPG gas of a predetermined pressure, and injected from an LPG fuel injection valve into an intake manifold.
A relief valve that opens a valve port at a set differential pressure is connected between the LPG passage connecting the vaporizer and the LPG fuel injection valve and the intake manifold,
When the pressure difference between the LPG passage and the intake manifold reaches a set pressure, the valve port of the relief valve is automatically opened, and the LPG gas in the LPG passage is directly discharged into the intake manifold. Pressure rise prevention device for an LPG injection engine. 前記リリーフ弁を並列に複数個設け、各リリーフ弁の作動圧力を段階的に変えたことを特徴とする請求項１記載のＬＰＧ噴射式エンジンの燃圧上昇防止装置。2. The fuel pressure rise prevention device for an LPG injection engine according to claim 1, wherein a plurality of said relief valves are provided in parallel, and the operating pressure of each relief valve is changed stepwise. 前記ＬＰＧボンベとベーパライザーとの間を結ぶ液化ＬＰＧ通路にＬＰＧ燃料遮断弁を設けるとともに、前記ベーパライザーとＬＰＧ燃料噴射弁との間をむすぶＬＰＧ通路にはＬＰＧ燃圧センサーを設け、
前記ＬＰＧ通路の圧力が設定圧力以上になったことをＬＰＧ燃圧センサーが検出したときに前記ＬＰＧ燃料遮断弁を作動し、ＬＰＧボンベからベーパライザーに送給されるＬＰＧ燃料を強制的に遮断するようにしたことを特徴とする請求項１または２記載のＬＰＧ噴射式エンジンの燃圧上昇防止装置。An LPG fuel cutoff valve is provided in a liquefied LPG passage connecting the LPG cylinder and the vaporizer, and an LPG fuel pressure sensor is provided in an LPG passage connecting the vaporizer and the LPG fuel injection valve,
When the LPG fuel pressure sensor detects that the pressure in the LPG passage has become equal to or higher than a set pressure, the LPG fuel cutoff valve is operated to forcibly cut off LPG fuel supplied from the LPG cylinder to the vaporizer. The fuel pressure rise prevention device for an LPG injection engine according to claim 1 or 2, wherein:
JP2003162131A 2003-06-06 2003-06-06 Fuel pressure rise prevention device for LPG injection type engine Expired - Fee Related JP4300308B2 (en)

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JP2003162131A JP4300308B2 (en) 2003-06-06 2003-06-06 Fuel pressure rise prevention device for LPG injection type engine
US10/861,641 US6988489B2 (en) 2003-06-06 2004-06-04 Fuel injection valve protecting apparatus and fuel pressure increase preventing apparatus in LPG injection type engine

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007064201A (en) * 2005-08-30 2007-03-15 Hyundai Motor Co Ltd Lpi engine system
JP2007332879A (en) * 2006-06-15 2007-12-27 Toyota Motor Corp Fuel supply device of internal combustion engine
WO2008062702A1 (en) * 2006-11-22 2008-05-29 Toyota Jidosha Kabushiki Kaisha Fuel cell system
JP2008274894A (en) * 2007-05-07 2008-11-13 Nikki Co Ltd Lpg fuel supply method and device thereof

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007064201A (en) * 2005-08-30 2007-03-15 Hyundai Motor Co Ltd Lpi engine system
JP2007332879A (en) * 2006-06-15 2007-12-27 Toyota Motor Corp Fuel supply device of internal combustion engine
WO2008062702A1 (en) * 2006-11-22 2008-05-29 Toyota Jidosha Kabushiki Kaisha Fuel cell system
JP2008130447A (en) * 2006-11-22 2008-06-05 Toyota Motor Corp Fuel cell system
US8153322B2 (en) 2006-11-22 2012-04-10 Toyota Jidosha Kabushiki Kaisha Fuel cell system having an injector
KR101136498B1 (en) * 2006-11-22 2012-04-19 도요타 지도샤（주） Fuel cell system
JP2008274894A (en) * 2007-05-07 2008-11-13 Nikki Co Ltd Lpg fuel supply method and device thereof

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