JP3289472B2 - Fuel injection control device - Google Patents

Fuel injection control device

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Publication number
JP3289472B2
JP3289472B2 JP04412994A JP4412994A JP3289472B2 JP 3289472 B2 JP3289472 B2 JP 3289472B2 JP 04412994 A JP04412994 A JP 04412994A JP 4412994 A JP4412994 A JP 4412994A JP 3289472 B2 JP3289472 B2 JP 3289472B2
Authority
JP
Japan
Prior art keywords
fuel
engine
fuel injection
pressure
stopped
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
JP04412994A
Other languages
Japanese (ja)
Other versions
JPH07253041A (en
Inventor
匡彦 増渕
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyota Motor Corp
Original Assignee
Toyota Motor Corp
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Filing date
Publication date
Application filed by Toyota Motor Corp filed Critical Toyota Motor Corp
Priority to JP04412994A priority Critical patent/JP3289472B2/en
Publication of JPH07253041A publication Critical patent/JPH07253041A/en
Application granted granted Critical
Publication of JP3289472B2 publication Critical patent/JP3289472B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • 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

Landscapes

  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)
  • Electrical Control Of Ignition Timing (AREA)
  • Fuel-Injection Apparatus (AREA)

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【産業上の利用分野】本発明は、内燃機関の燃料噴射制
御装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection control device for an internal combustion engine.

【０００２】[0002]

【従来の技術】加圧燃料を燃料噴射弁から噴射して各気
筒に供給する燃料噴射装置を有する内燃機関では、機関
を停止した後の燃料油温度の上昇による、燃料系内の気
泡発生により機関の再始動が困難になる問題が生じる場
合がある。すなわち、内燃機関を停止後は、燃料噴射弁
からの燃料の噴射が停止するために、燃料噴射弁に燃料
を供給する燃料通路内は、流れがなくなって燃料が滞留
した状態になる。このように燃料通路内に滞留した燃料
油は、機関や排気系の熱を受けて温度が上昇し、ある程
度以上の温度になると燃料通路や燃料噴射弁内で気化し
て燃料油蒸気の気泡を生じるようになる。ところが、機
関を再始動する際に燃料通路や燃料噴射弁内に気泡が存
在すると、燃料噴射弁から始動に必要な量の燃料を噴射
することができず再始動が困難となる、いわゆるベーパ
ーロックの問題が生じるのである。特に、車両用機関等
では、機関停止後（車両停止後）は車両走行風がなくな
るため、エンジンルーム内の温度上昇が大きくなりベー
パーロックが生じ易くなる。2. Description of the Related Art In an internal combustion engine having a fuel injection device that injects pressurized fuel from a fuel injection valve and supplies the fuel to each cylinder, bubbles in a fuel system are generated due to a rise in fuel oil temperature after the engine is stopped. There may be a case where it becomes difficult to restart the engine. That is, after the internal combustion engine is stopped, the injection of fuel from the fuel injection valve is stopped, so that the fuel flow in the fuel passage for supplying fuel to the fuel injection valve is stopped, and the fuel remains. The temperature of the fuel oil that has accumulated in the fuel passage increases due to the heat of the engine and the exhaust system, and when the temperature exceeds a certain level, the fuel oil vaporizes in the fuel passage and the fuel injection valve to form bubbles of fuel oil vapor. Will occur. However, when air bubbles are present in the fuel passage and the fuel injection valve when the engine is restarted, the fuel injection valve cannot inject the necessary amount of fuel for starting and it is difficult to restart the engine. The problem arises. In particular, in a vehicle engine or the like, after the engine stops (after the vehicle stops), the wind running through the vehicle disappears, so that the temperature in the engine room rises greatly and vapor lock easily occurs.

【０００３】このベーパーロックが生じることを防止す
るため、例えば特開昭５９−４６３６０号公報に記載の
装置では、燃料通路から余剰燃料を燃料タンクに戻すリ
ターンパイプを設け、機関停止後も燃料ポンプから燃料
通路に燃料を供給して上記リターンパイプから燃料タン
クに循環させることにより、燃料通路に生じた気泡を燃
料タンク内に排出するようにしている。In order to prevent the occurrence of the vapor lock, for example, in a device described in Japanese Patent Application Laid-Open No. S59-46360, a return pipe for returning surplus fuel from a fuel passage to a fuel tank is provided. By supplying fuel to the fuel passage from the fuel tank and circulating the fuel from the return pipe to the fuel tank, bubbles generated in the fuel passage are discharged into the fuel tank.

【０００４】また、例えば実開昭６２−１１９４７４号
公報に記載の装置では、機関停止時に燃料通路内の燃料
圧力を上昇させる手段を設け、機関停止後に燃料通路内
の圧力を燃料蒸気圧より高い圧力になるように昇圧し
て、燃料通路内での燃料の気化を防止することにより気
泡の発生を防止している。Further, for example, in the apparatus described in Japanese Utility Model Application Laid-Open No. 62-119474, means for increasing the fuel pressure in the fuel passage when the engine is stopped is provided, and after the engine is stopped, the pressure in the fuel passage is higher than the fuel vapor pressure. The pressure is raised to a pressure to prevent vaporization of the fuel in the fuel passage, thereby preventing generation of bubbles.

【０００５】[0005]

【発明が解決しようとする課題】ところが、上記特開昭
５９−４６３６０号公報に記載の装置のように、機関停
止後燃料通路内の燃料をタンク内に循環させるようにし
た場合、機関停止後に燃料通路内で加熱された燃料がタ
ンク内に流入することになるため、タンク内の燃料温度
が上昇し、タンク内の燃料の蒸発によりエバポエミッシ
ョン（EVAPORATIVE EMISSION) が増大する問題が生じ
る。また、この装置では、気泡発生を防止するために燃
料通路と燃料タンクとを接続するリターンパイプを設け
る必要が生じるとともに、更に機関停止後も一定の期間
燃料供給ポンプの運転を継続する必要があり、装置が複
雑化する問題がある。However, when the fuel in the fuel passage is circulated in the tank after the engine stops, as in the apparatus described in Japanese Patent Application Laid-Open No. Sho 59-46360, after the engine stops. Since the fuel heated in the fuel passage flows into the tank, the fuel temperature in the tank rises, and the evaporation of the fuel in the tank causes a problem that the evaporative emission (EVAPORATIVE EMISSION) increases. Further, in this device, it is necessary to provide a return pipe connecting the fuel passage and the fuel tank in order to prevent the generation of air bubbles, and furthermore, it is necessary to continue the operation of the fuel supply pump for a certain period after the engine is stopped. However, there is a problem that the device becomes complicated.

【０００６】一方、上記実開昭６２−１１９４７４号公
報の装置では、上記のようなリターンパイプ等を設ける
必要がなく、エバポエミッションの増大等の問題は生じ
ないものの、燃料通路内の圧力を上昇させるために問題
が生じる場合がある。すなわち、前述のように機関停止
後は燃料通路内の燃料油は機関や排気系の熱をうけて温
度が上昇する。このため、燃料通路内の燃料油に熱膨張
を生じることになる。ところが、燃料噴射停止後は燃料
通路は出口が閉鎖された状態となり、通路内容積は変化
しないため、通路内の燃料油の熱膨張により燃料油圧力
が上昇する。また、機関停止時の燃料油圧力が高けれ
ば、熱膨張により到達する燃料油圧力も高くなる。この
ため、上記実開昭６２−１１９４７４号公報の装置のよ
うに機関停止時に燃料通路内の圧力を上昇させると、機
関停止後の燃料油圧力が極めて高くなる場合が生じる。On the other hand, in the apparatus disclosed in Japanese Utility Model Application Laid-Open No. Sho 62-119474, it is not necessary to provide a return pipe as described above, and there is no problem such as an increase in evaporative emission. May cause problems. That is, as described above, after the engine stops, the temperature of the fuel oil in the fuel passage increases due to the heat of the engine and the exhaust system. For this reason, thermal expansion occurs in the fuel oil in the fuel passage. However, after the fuel injection is stopped, the outlet of the fuel passage is closed, and the volume in the passage does not change. Therefore, the fuel oil pressure increases due to the thermal expansion of the fuel oil in the passage. Also, if the fuel oil pressure at the time of engine stop is high, the fuel oil pressure reached by thermal expansion also becomes high. Therefore, when the pressure in the fuel passage is increased when the engine is stopped as in the apparatus disclosed in Japanese Utility Model Application Laid-Open No. Sho 62-119474, the fuel oil pressure after the engine is stopped may become extremely high.

【０００７】一般に、燃料噴射弁としては開弁時に弁体
が内部の燃料油圧力に対抗する方向に作動する内開弁が
使用される。ところが、上記のように機関停止後燃料通
路内の燃料油圧力が高くなっている状態で機関を再始動
しようとすると、弁体の駆動力より、弁内部の燃料油圧
力が弁体に作用する力の方が大きくなるような場合が生
じる。このような状態が生じると、燃料噴射弁からの燃
料噴射ができなくなるため機関が始動不能に陥ることに
なる。[0007] Generally, as a fuel injection valve, an inner valve is used in which a valve element operates in a direction opposing the internal fuel oil pressure when the valve is opened. However, when the engine is restarted in a state where the fuel oil pressure in the fuel passage is high after the engine is stopped as described above, the fuel oil pressure inside the valve acts on the valve body due to the driving force of the valve body. In some cases, the force becomes larger. When such a state occurs, the engine cannot be started because fuel cannot be injected from the fuel injection valve.

【０００８】上記は、ベーパーロックの防止のために機
関停止後燃料油圧力を上昇させる場合について述べた
が、例えば気筒内に直接燃料を噴射する筒内燃料噴射弁
を備えた機関では、高圧の筒内に燃料を噴射するため燃
料噴射圧力は比較的高圧に設定するのが通常であり、燃
料通路内圧力は通常運転時も高くなっている。このた
め、機関停止時に特に燃料油の昇圧を行わない場合で
も、機関停止後の燃料油圧力上昇により、上記のような
機関再始動不能の問題が生じる場合がある。In the above description, the case where the fuel oil pressure is increased after the engine is stopped in order to prevent the vapor lock has been described. For example, in an engine provided with an in-cylinder fuel injection valve for directly injecting fuel into a cylinder, a high pressure oil is used. In order to inject fuel into the cylinder, the fuel injection pressure is usually set to a relatively high pressure, and the pressure in the fuel passage is also high during normal operation. Therefore, even when the fuel oil pressure is not particularly increased when the engine is stopped, the above-described problem that the engine cannot be restarted may occur due to an increase in the fuel oil pressure after the engine is stopped.

【０００９】内開弁に代えて、弁体が内部の圧力に対抗
する方向に閉じる形式の、いわゆる外開弁を使用すれば
上記始動不能の問題は生じないものの、外開弁では逆に
機関停止後の燃料油圧力上昇により、燃料油から弁体に
作用する開弁方向の力が閉弁方向の力より大きくなる
と、燃料噴射弁が急激に自然開弁してしまう問題が生じ
る。このように高圧下で外開弁が急激に開弁すると、燃
料通路内にウォータハンマーによる大きな圧力変動が生
じ、極端な場合には燃料系の構成部品が損傷するような
場合が生じる。If a so-called external opening valve in which the valve element closes in a direction opposing the internal pressure is used instead of the internal opening, the above-described problem of inability to start does not occur. If the force in the valve-opening direction acting on the valve body from the fuel oil becomes larger than the force in the valve-closing direction due to the increase in the fuel oil pressure after the stop, a problem arises in that the fuel injector rapidly opens naturally. When the external valve is suddenly opened under high pressure as described above, a large pressure fluctuation occurs in the fuel passage due to the water hammer, and in extreme cases, components of the fuel system may be damaged.

【００１０】一方、前述の特開昭６２−１１９４７４号
公報のように、燃料通路に燃料タンクに連通するリター
ン通路を設け、燃料通路内の圧力上昇時に余剰の燃料を
タンク内に放出すればこの問題を防止することは可能で
あるが、この場合前述のように装置の複雑化や、エバポ
エミッションの増大を生じる問題が発生する。また、内
開弁形式の燃料噴射弁の駆動ソレノイドを大型化して燃
料噴射弁の作動可能な限界圧力を高めたり、外開弁形式
の燃料噴射弁の閉弁スプリングの付勢力を高めることに
より自然開弁圧力を高めることも可能であるが、燃料噴
射弁の大型化や製品コストの増大を生じることになり好
ましくない。On the other hand, as described in Japanese Patent Application Laid-Open No. 62-119474, a return passage communicating with the fuel tank is provided in the fuel passage so that excess fuel is discharged into the tank when the pressure in the fuel passage increases. Although it is possible to prevent the problem, in this case, as described above, a problem occurs that the device becomes complicated and the evaporative emission increases. Also, by increasing the size of the drive solenoid of the inner-open type fuel injection valve to increase the operable limit pressure of the fuel injection valve, or by increasing the urging force of the closing spring of the outer-open type fuel injection valve, Although it is possible to increase the valve opening pressure, it is not preferable because the size of the fuel injection valve increases and the product cost increases.

【００１１】本発明は上記問題に鑑み、機関停止後の温
度上昇にともなう燃料油圧力の上昇により生じる上記問
題を簡易に解決する手段を提供することを目的としてい
る。The present invention has been made in view of the above problems, and has as its object to provide means for easily solving the above problems caused by an increase in fuel oil pressure accompanying an increase in temperature after the engine is stopped.

【００１２】[0012]

【課題を解決するための手段】請求項１に記載の本発明
によれば、加圧燃料が供給される燃料通路と、前記燃料
通路内の燃料を内燃機関の気筒内に噴射する燃料噴射弁
と、前記燃料噴射弁の燃料噴射動作を制御する制御手段
とを備えた内燃機関の燃料噴射制御装置において、機関
停止時の機関冷却水温度と外気温度とに基づいて、機関
停止後の温度上昇による前記燃料通路内の燃料圧力の最
大到達値を推定する推定手段を備え、前記制御手段は、
前記推定された圧力最大到達値が予め定めた所定値以上
の場合、機関停止直後に前記燃料噴射弁からの燃料噴射
を行って前記燃料通路内の圧力を低下させることを特徴
とする内燃機関の燃料噴射制御装置が提供される。According to the present invention, there is provided a fuel passage for supplying pressurized fuel, and a fuel injection valve for injecting fuel in the fuel passage into a cylinder of an internal combustion engine. And a control means for controlling the fuel injection operation of the fuel injection valve, the temperature increase after the engine is stopped based on the engine cooling water temperature and the outside air temperature when the engine is stopped. Estimating means for estimating the maximum value of the fuel pressure in the fuel passage by the, the control means,
When the estimated maximum pressure value is equal to or greater than a predetermined value, the fuel injection from the fuel injection valve is performed immediately after the engine stops to reduce the pressure in the fuel passage. A fuel injection control device is provided.

【００１３】更に、請求項２に記載の本発明によれば、
請求項１において、前記制御手段は前記機関停止時に前
記燃料噴射弁からの燃料噴射を行うときに、吸気弁と排
気弁との両方が閉弁している気筒の燃料噴射弁からのみ
燃料噴射を行うようにした燃料噴射弁制御装置が提供さ
れる。Further, according to the present invention as set forth in claim 2 ,
In claim 1, the control means, when performing fuel injection from the fuel injection valve when the engine is stopped, performs fuel injection only from a fuel injection valve of a cylinder in which both the intake valve and the exhaust valve are closed. A fuel injector control device adapted to perform the above is provided.

【００１４】[0014]

【作用】請求項１に記載の本発明では、推定手段により
推定された燃料油圧力の最大到達値が、内開弁形式の燃
料噴射弁の作動不能となる限界圧力や、外開弁形式の燃
料噴射弁が自然開弁する限界圧力などの所定の圧力以上
になる場合には、制御手段は機関停止後も燃料噴射を継
続させ燃料通路内の燃料油圧力を低下させるため、燃料
油温度が上昇しても燃料油圧力は上記限界圧力には到達
せず、燃料噴射弁の作動不能や自然開弁などの問題が生
じない。According to the first aspect of the present invention, the maximum value of the fuel oil pressure estimated by the estimating means is determined by the limit pressure at which the inner-valve type fuel injection valve becomes inoperable or the outer-valve type. If the fuel injection valve is at or above a predetermined pressure, such as the limit pressure at which the fuel injection valve opens naturally, the control means continues fuel injection even after the engine is stopped and reduces the fuel oil pressure in the fuel passage. Even when the fuel oil pressure rises, the fuel oil pressure does not reach the above-mentioned limit pressure, so that problems such as inability to operate the fuel injection valve and natural valve opening do not occur.

【００１５】また、請求項２に記載の本発明では、請求
項１において燃料噴射を継続する際に、吸気弁と排気弁
との両方が閉弁している気筒にのみ燃料噴射が行われる
ため、噴射された燃料は気筒内に留まり、次回の機関始
動時に燃焼する。このため、噴射した燃料が蒸発燃料と
して大気に放出されることがなく、さらに再始動時には
燃焼室内に確実に燃料が存在する気筒があるため機関の
始動が良好になる。According to the second aspect of the present invention, when the fuel injection is continued in the first aspect, the fuel is injected only into the cylinder in which both the intake valve and the exhaust valve are closed. The injected fuel remains in the cylinder and burns the next time the engine is started. For this reason, the injected fuel is not released to the atmosphere as evaporative fuel. Further, at the time of restart, there is a cylinder in which fuel is reliably present in the combustion chamber, so that the engine starts well.

【００１６】[0016]

【実施例】図１は本発明を適用する内燃機関の燃料噴射
系統の概略構成図を示している。図１において、１は内
燃機関の各気筒内に燃料を直接噴射する燃料噴射弁、３
は燃料噴射弁１に加圧燃料を供給するデリバリパイプ、
５はデリバリパイプ３に燃料を圧送する高圧ダイヤフラ
ムポンプ、７は燃料タンク、９は燃料フィードポンプを
それぞれ示している。FIG. 1 is a schematic structural view of a fuel injection system of an internal combustion engine to which the present invention is applied. In FIG. 1, reference numeral 1 denotes a fuel injection valve for directly injecting fuel into each cylinder of the internal combustion engine;
Is a delivery pipe for supplying pressurized fuel to the fuel injection valve 1,
Reference numeral 5 denotes a high-pressure diaphragm pump for pumping fuel to the delivery pipe 3, reference numeral 7 denotes a fuel tank, and reference numeral 9 denotes a fuel feed pump.

【００１７】機関運転中、タンク７内の燃料は、フィー
ドポンプ９により昇圧され、フィルタ１１を通過して異
物を除去され、プレッシャレギュレータ１３により一定
の圧力（１次圧力、例えば０．３ＭＰａ程度）に圧力調
整された後、高圧ダイヤフラムポンプ５に供給される。
また、高圧ダイヤフラムポンプ５から吐出された燃料
は、逆止弁１５、高圧配管１７を通ってデリバリパイプ
３に供給され、デリバリパイプ３から燃料噴射弁１を介
して内燃機関の各気筒内に噴射される。During operation of the engine, the fuel in the tank 7 is pressurized by the feed pump 9, passes through the filter 11 to remove foreign substances, and is maintained at a constant pressure (primary pressure, for example, about 0.3 MPa) by the pressure regulator 13. After the pressure is adjusted to, the pressure is supplied to the high-pressure diaphragm pump 5.
The fuel discharged from the high-pressure diaphragm pump 5 is supplied to the delivery pipe 3 through the check valve 15 and the high-pressure pipe 17, and is injected from the delivery pipe 3 into each cylinder of the internal combustion engine via the fuel injection valve 1. Is done.

【００１８】図１に２０で示すのは、機関の制御を行う
エンジン制御回路（ＥＣＵ）である。ＥＣＵ２０は、リ
ードオンリメモリ（ＲＯＭ）、ランダムアクセスメモリ
（ＲＡＭ）、マイクロプロセッサ（ＣＰＵ）、入出力ポ
ートを双方向バスで接続した公知の構成のディジタルコ
ンピュータから成っている。ＥＣＵ２０は、高圧ダイヤ
フラムポンプ５のストロークを制御してデリバリパイプ
３内の燃料油圧力（２次圧力）を機関負荷、回転数等に
応じて制御する燃圧制御を行う他、燃料噴射弁１の開弁
時間を制御して気筒内に供給される燃料量の制御、機関
点火時期の制御、等の機関の基本制御を行う。また、本
実施例では、機関停止時の機関運転状態から、機関停止
後のデリバリパイプ３内の燃料油の最大到達圧力を推定
する推定手段や、機関停止後に燃料噴射を継続してデリ
バリパイプ３内の圧力を低下させる制御手段としての機
能を果たしている。FIG. 1 shows an engine control circuit (ECU) 20 for controlling the engine. The ECU 20 comprises a digital computer having a known configuration in which a read-only memory (ROM), a random access memory (RAM), a microprocessor (CPU), and an input / output port are connected by a bidirectional bus. The ECU 20 controls the stroke of the high-pressure diaphragm pump 5 to perform fuel pressure control for controlling the fuel oil pressure (secondary pressure) in the delivery pipe 3 according to the engine load, the number of revolutions, and the like, and also opens the fuel injection valve 1. By controlling the valve time, basic control of the engine such as control of the amount of fuel supplied into the cylinder and control of the engine ignition timing is performed. Further, in the present embodiment, the estimating means for estimating the maximum attainable pressure of the fuel oil in the delivery pipe 3 after the engine stops from the engine operating state when the engine stops, and the delivery pipe 3 by continuing the fuel injection after the engine stops. It functions as a control means for reducing the internal pressure.

【００１９】上記制御のため、ＥＣＵ２０の入力ポート
には、デリバリパイプ３に設けた燃圧センサ３１からデ
リバリパイプ３内の燃料圧力に対応する電圧信号が、ま
た、冷却水温度センサ３３から機関冷却水温度に対応す
る電圧信号がそれぞれＡＤ変換器３４を介して入力され
ている他、機関吸気通路に設けたエアフローメータ３５
から吸気温度と機関吸入空気量に対応する信号がそれぞ
れ同様にＡＤ変換器３４を介して入力されている。更
に、ＥＣＵ２０の入力ポートには、機関のディストリビ
ュータ（図示せず）に設けたクランク角センサ３７か
ら、クランク回転角に応じて発生する、後述するＮｅパ
ルス信号とＧパルス信号との２つの信号が入力されてい
る。For the above control, an input port of the ECU 20 receives a voltage signal corresponding to the fuel pressure in the delivery pipe 3 from the fuel pressure sensor 31 provided in the delivery pipe 3 and an engine cooling water from the cooling water temperature sensor 33 to the input port. A voltage signal corresponding to the temperature is input via the AD converter 34, and an air flow meter 35 provided in the engine intake passage.
, Signals corresponding to the intake air temperature and the engine intake air amount are similarly input via the AD converter 34. Further, at an input port of the ECU 20, two signals, Ne pulse signal and G pulse signal, which will be described later, generated according to the crank rotation angle from a crank angle sensor 37 provided in a distributor (not shown) of the engine are provided. Has been entered.

【００２０】また、ＥＣＵ２０の出力ポートは、駆動回
路４０を介して燃料噴射弁１に接続され、各燃料噴射弁
１の作動を制御している他、駆動回路４０を介して高圧
ダイヤフラムポンプ５の容量制御装置に接続され、ポン
プ５の吐出量を制御している。また、ＥＣＵ２０の出力
ポートは点火回路４１を介して、機関の点火プラグ（図
示せず）に接続され、各気筒の点火制御を行っている。The output port of the ECU 20 is connected to the fuel injection valves 1 via a drive circuit 40 to control the operation of each of the fuel injection valves 1 and to control the operation of the high-pressure diaphragm pump 5 via the drive circuit 40. It is connected to a capacity control device and controls the discharge amount of the pump 5. An output port of the ECU 20 is connected to an ignition plug (not shown) of the engine via an ignition circuit 41, and performs ignition control of each cylinder.

【００２１】本実施例では、ＥＣＵ２０はデリバリパイ
プ３内の燃料油２次圧力を、通常の運転時においては５
ＭＰａ程度の圧力に制御している。従って運転停止（燃
料噴射停止）時には、デリバリパイプ３内の燃料油圧力
は５ＭＰａ程度になっている。この状態で機関の運転が
停止されるとデリバリパイプ３内の燃料油は機関自体や
排気系の熱を受けて温度が上昇し、燃料油の熱膨張によ
りデリバリパイプ３内の燃料油圧力は上昇する。In this embodiment, the ECU 20 sets the fuel oil secondary pressure in the delivery pipe 3 to 5 during normal operation.
The pressure is controlled to about MPa. Therefore, when the operation is stopped (the fuel injection is stopped), the fuel oil pressure in the delivery pipe 3 is about 5 MPa. When the operation of the engine is stopped in this state, the temperature of the fuel oil in the delivery pipe 3 increases due to the heat of the engine itself and the exhaust system, and the pressure of the fuel oil in the delivery pipe 3 increases due to thermal expansion of the fuel oil. I do.

【００２２】図２は、機関停止後のデリバリパイプ３内
の燃料油圧力の時間的変化を説明する図である。図２に
示すように、機関停止後デリバリパイプ３内の燃料圧力
は時間とともに上昇し、ある時間が経過すると最大値に
到達する。また、その後は機関の冷却とともにデリバリ
パイプ内の圧力は低下して行く。ところが、前述のよう
に、燃料噴射弁には、作動限界圧力（内開弁の場合）や
自然開弁圧力（外開弁の場合）が存在する。例えば、本
実施例では内開弁形式の燃料噴射弁が使用されており、
作動限界圧力は約７ＭＰａである。このため、機関停止
後燃料圧力が上昇してこの作動限界圧力を越える期間
（例えば図２、区間Ａ）が生じると、この期間内では燃
料噴射を行えず機関の再始動ができなくなる問題が生じ
る。FIG. 2 is a view for explaining a temporal change of the fuel oil pressure in the delivery pipe 3 after the engine is stopped. As shown in FIG. 2, after the engine stops, the fuel pressure in the delivery pipe 3 increases with time, and reaches a maximum value after a lapse of a certain time. Thereafter, the pressure in the delivery pipe decreases as the engine cools. However, as described above, the fuel injection valve has an operating limit pressure (in the case of internal opening) and a natural valve opening pressure (in the case of external opening). For example, in this embodiment, a fuel injection valve of an internal valve type is used,
The operating limit pressure is about 7 MPa. For this reason, if the fuel pressure rises after the engine is stopped and exceeds the operating limit pressure (for example, section A in FIG. 2), fuel injection cannot be performed during this period, and the engine cannot be restarted. .

【００２３】本実施例では、機関を停止する際に、機関
冷却水温度と外気温度（機関吸気温度）とに基づいて機
関停止後のデリバリパイプ３内の最大到達圧力を推定
し、この推定最大圧力が上記燃料噴射弁の作動限界圧力
を越える場合、すなわち機関停止後に再始動不能となる
期間が生じる場合には、機関停止直後に燃料噴射を行う
ことにより、図２に点線で示したように、デリバリパイ
プ３内圧力を機関停止後に上記再始動不能期間が生じな
い程度まで低下させる減圧制御を行う。In the present embodiment, when the engine is stopped, the maximum attainable pressure in the delivery pipe 3 after the engine is stopped is estimated based on the engine cooling water temperature and the outside air temperature (engine intake air temperature). If the pressure exceeds the operating limit pressure of the fuel injection valve, that is, if there is a period during which the engine cannot be restarted after the engine is stopped, fuel injection is performed immediately after the engine is stopped, as shown by the dotted line in FIG. In addition, pressure reduction control is performed to reduce the pressure in the delivery pipe 3 to such an extent that the above-mentioned restart impossible period does not occur after the engine is stopped.

【００２４】図３は、機関停止後のデリバリパイプ３内
の燃料油の最大到達圧力ＰMAX と機関冷却水温度ＴＨ
Ｗ、外気温（吸気温度）ＴＡＴＭとの関係を示す図であ
る。図３は機関停止前のデリバリパイプ３内圧力が５Ｍ
Ｐａの場合の最大到達圧力を示している。図３に示すよ
うに、機関停止後の最大到達圧力ＰMAX は停止時の機関
冷却水温ＴＨＷが高いほど、また外気温ＴＡＴＭが高い
ほど高くなり、冷却水温ＴＨＷが一定の限界値Ｔｅ以
上、かつ外気温ＴＡＴＭが一定の限界値Ｔａ以上の範囲
（図３斜線部分）では燃料噴射弁の作動限界圧力（７Ｍ
Ｐａ）を越えるようになる。FIG. 3 shows the maximum ultimate pressure P MAX of fuel oil in the delivery pipe 3 after the engine is stopped and the engine coolant temperature TH.
FIG. 7 is a diagram showing a relationship between W and an outside air temperature (intake air temperature) TATM. FIG. 3 shows that the pressure in the delivery pipe 3 before the engine stops is 5M.
It shows the maximum ultimate pressure in the case of Pa. As shown in FIG. 3, the maximum ultimate pressure P MAX after the engine is stopped increases as the engine cooling water temperature THW at the time of stoppage increases and as the outside air temperature TATM increases, and the cooling water temperature THW is equal to or higher than a certain limit value Te, and In the range where the outside air temperature TATM is equal to or higher than the certain limit value Ta (the shaded portion in FIG. 3), the operating limit pressure (7M
Pa).

【００２５】本実施例では、冷却水温度ＴＨＷと外気温
ＴＡＴＭが上記範囲にある場合には、機関停止後に燃料
噴射弁から所定量の燃料を噴射してデリバリパイプ３内
の燃料油圧力を低下させるが、この停止時に噴射する燃
料の量は、冷却水温度ＴＨＷと外気温ＴＡＴＭとに基づ
いて上記機関再始動不能期間が生じることを防止するの
に必要かつ十分な最小の量に設定される。In this embodiment, when the cooling water temperature THW and the outside air temperature TATM are in the above ranges, a predetermined amount of fuel is injected from the fuel injection valve after the engine is stopped to lower the fuel oil pressure in the delivery pipe 3. However, the amount of fuel injected at the time of the stop is set to a minimum amount necessary and sufficient to prevent the engine restart impossible period from occurring based on the cooling water temperature THW and the outside air temperature TATM. .

【００２６】図４は、機関停止時の燃料噴射量と冷却水
温ＴＨＷと外気温ＴＡＴＭとの関係を示す図である。図
４に示すように、減圧のための燃料噴射量ＴＡＵREは図
３の最大到達圧力に対応して、冷却水温度ＴＨＷが高い
ほど、また外気温ＴＡＴＭが高いほど大きく設定され
る。これにより、機関停止時には、デリバリパイプ３内
の圧力は機関停止後の燃料油の最大到達圧力が高いほど
大幅に低減されるため、機関停止後の最大到達圧力が燃
料噴射量の作動限界圧力を越えることがなくなり、機関
停止後に再始動不能期間が生じることが防止される。FIG. 4 is a diagram showing the relationship between the fuel injection amount when the engine is stopped, the cooling water temperature THW, and the outside air temperature TATM. As shown in FIG. 4, the fuel injection amount TAU RE for decompression corresponding to the maximum pressure reached 3, as the cooling water temperature THW is high, also the outside air temperature TATM is set higher increase. As a result, when the engine is stopped, the pressure in the delivery pipe 3 is greatly reduced as the maximum ultimate pressure of the fuel oil after the engine is stopped is higher. Therefore, the maximum ultimate pressure after the engine is stopped is lower than the operation limit pressure of the fuel injection amount. As a result, it is possible to prevent the restart impossible period from occurring after the engine stops.

【００２７】図５は、上記減圧制御動作を示すフローチ
ャートである。本ルーチンは、ＥＣＵ２０により機関運
転停止時（イグニッションスイッチがＯＦＦにされたと
き）に一度だけ実行される。図５においてイグニッショ
ンスイッチがＯＦＦにされると、ステップ５０１ではＥ
ＣＵ２０の電源オフが遅延され、イグニッションＯＦＦ
後もステップ５０３以下の処理が実行可能となる。FIG. 5 is a flowchart showing the pressure reduction control operation. This routine is executed only once by the ECU 20 when the engine operation is stopped (when the ignition switch is turned off). When the ignition switch is turned off in FIG.
Power off of CU20 is delayed and ignition is turned off
After that, the processing from step 503 can be executed.

【００２８】次いでステップ５０３では、機関冷却水温
度ＴＨＷがセンサ３３から読み込まれるとともに、読み
込んだＴＨＷが前述の限界値Ｔｅより大きいか否かが判
定され、ステップ５０５ではエアフローメータ３５の吸
気温度センサから外気温ＴＡＴＭが読み込まれ、このＴ
ＡＴＭが前述の限界値Ｔａより大きいか否かが判定され
る。Next, at step 503, the engine cooling water temperature THW is read from the sensor 33, and it is determined whether or not the read THW is greater than the above-mentioned limit value Te. At step 505, it is determined from the intake air temperature sensor of the air flow meter 35. The outside temperature TATM is read and this T
It is determined whether the ATM is larger than the above-described limit value Ta.

【００２９】ステップ５０３、５０５のいずれかが成立
しない場合には、ルーチンはステップ５１５に進み、Ｅ
ＣＵ２０の電源をＯＦＦにした後ルーチンを終了する。
すなわち、図３で説明したように機関停止後の燃料油最
大到達圧力ＰMAX が燃料噴射弁の作動限界圧力を越える
のは、冷却水温度ＴＨＷと外気温ＴＡＴＭとの両方が上
記限界値を越える場合である。このため、ステップ５０
３、５０５のいずれか一方が成立しない場合には、減圧
のための燃料噴射を行わなくても再始動不能期間が生じ
ることはないので、ステップ５０７から５１３を実行す
ることなくルーチンを終了する。If one of steps 503 and 505 does not hold, the routine proceeds to step 515, where E
After the power of the CU 20 is turned off, the routine ends.
That is, the fuel oil up to the ultimate pressure P MAX after the engine stop as described in FIG. 3 that exceeds the critical actuation pressure of the fuel injection valve, both the coolant temperature THW and the outside air temperature TATM is beyond the above limit value Is the case. Therefore, step 50
If either one of the conditions 3 and 505 is not established, the restart impossible period does not occur even if the fuel injection for reducing the pressure is not performed. Therefore, the routine ends without executing steps 507 to 513.

【００３０】また、ステップ５０３、５０５の両方が成
立した場合には、ステップ５０７に進み、上記冷却水温
度ＴＨＷと外気温ＴＡＴＭとに基づいて図４の関係から
減圧のための燃料噴射量ＴＡＵREが決定される。本実施
例では、図４の関係はＥＣＵ２０のＲＯＭに予め数値マ
ップの形で格納されており、ステップ５０７ではこのマ
ップから減圧のための燃料噴射量ＴＡＵREが読み出され
る。If both steps 503 and 505 are established, the routine proceeds to step 507, where the fuel injection amount TAU RE for pressure reduction is determined based on the cooling water temperature THW and the outside air temperature TATM from the relationship shown in FIG. Is determined. In the present embodiment, the relationship of FIG. 4 is stored in advance in the ROM of the ECU 20 in the form of a numerical map, and in step 507, the fuel injection amount TAU RE for pressure reduction is read from this map.

【００３１】次いで、ステップ５０９では減圧のための
燃料噴射を行う気筒を決定する。この決定方法について
は後に述べる。また、上記決定後、ステップ５１１で
は、駆動回路４０を介して上記により決定された気筒の
燃料噴射弁を駆動し、ＴＡＵREの量の燃料噴射を行う。
また、上記に続いて、図５、ステップ５１３に示すよう
に燃料噴射を行った気筒の点火プラグに放電電圧を印加
して噴射した燃料を燃焼させるようにすれば、噴射され
た燃料が蒸発燃料として大気に放出されることを完全に
防止できる。Next, at step 509, a cylinder for performing fuel injection for pressure reduction is determined. This determination method will be described later. Further, after the above determination, in step 511, via the drive circuit 40 drives the fuel injection valve of the cylinder determined by the, performing fuel injection amount TAU RE.
Further, following the above, if the discharge fuel is applied to the ignition plug of the cylinder in which the fuel injection has been performed to burn the injected fuel as shown in step 513 in FIG. Can be completely prevented from being released into the atmosphere.

【００３２】上記の減圧制御を実行後、ステップ５１５
ではＥＣＵ２０の電源がＯＦＦにされ、本ルーチンは終
了する。なお、本実施例では機関停止後、燃料油圧力が
燃料噴射弁の作動限界圧力を越える場合にのみ減圧のた
めの燃料噴射を行うようにしているため、実際に減圧の
ための燃料噴射が実施される頻度は比較的少なくなって
いる。After executing the above pressure reduction control, step 515 is executed.
Then, the power supply of the ECU 20 is turned off, and this routine ends. In this embodiment, after the engine is stopped, the fuel injection for reducing the pressure is performed only when the fuel oil pressure exceeds the operating limit pressure of the fuel injection valve. The frequency is relatively low.

【００３３】次に、上記ステップ５０９における燃料噴
射気筒の決定について説明する。減圧のための燃料噴射
は、機関運転中の燃料噴射制御をそのまま継続した場合
に機関停止時に次に燃料噴射を行うことになっていた気
筒に行うようにしてもよいが、この場合機関停止のタイ
ミングによっては、この気筒の吸気弁または排気弁が開
弁している可能性があり、噴射された燃料が機関停止後
に蒸発して吸気弁または排気弁から気筒外に排出され、
吸気通路または排気通路から大気に放出される可能性が
ある。このため、次に燃料噴射を行うことが予定されて
いた気筒に燃料噴射を行う場合には、燃料噴射ととも
に、図５ステップ５１３に示したように噴射燃料に点火
して燃焼させることが好ましい。Next, the determination of the fuel injection cylinder in step 509 will be described. The fuel injection for the pressure reduction may be performed on the cylinder which is to perform the next fuel injection when the engine is stopped if the fuel injection control during the operation of the engine is continued as it is. Depending on the timing, the intake valve or exhaust valve of this cylinder may be open, the injected fuel evaporates after the engine stops and is discharged from the intake valve or exhaust valve to the outside of the cylinder,
It may be released to the atmosphere from an intake passage or an exhaust passage. For this reason, when performing fuel injection to the cylinder for which fuel injection is to be performed next, it is preferable to ignite and burn the injected fuel together with the fuel injection as shown in step 513 in FIG.

【００３４】なお、上記ステップ５０９において、吸気
弁と排気弁との両方が閉弁している気筒に機関停止時の
燃料噴射を行うようにすれば噴射された燃料は気筒内に
留まり、蒸発燃料が大気に放出されることが防止され
る。以下に説明する実施例では、ステップ５０９でＮｅ
信号とＧ信号との２つのクランク回転角パルス信号に基
づいて、吸気弁と排気弁との両方が閉弁している気筒、
すなわち圧縮行程上死点近傍にある気筒を判別し、その
気筒に燃料噴射を行うようにしている。In step 509, if the engine is stopped and the fuel is injected into the cylinder in which both the intake valve and the exhaust valve are closed, the injected fuel stays in the cylinder and the fuel is evaporated. Is prevented from being released to the atmosphere. In the embodiment described below, Ne is determined in Step 509.
A cylinder in which both the intake valve and the exhaust valve are closed based on two crank rotation angle pulse signals of a signal and a G signal;
That is, a cylinder near the top dead center of the compression stroke is determined, and fuel is injected into the cylinder.

【００３５】ここで、Ｎｅ信号、Ｇ信号は、機関ディス
トリビュータに設けられたクランク軸の２分の１の速度
で回転するロータの周囲に設けられた突起（歯）が、ロ
ータに近接配置された電磁ピックアップ位置を通過する
毎に発生するパルス信号であり、それぞれのロータ外周
の歯の形状を設定することにより、任意のパルス信号を
発生させることができる。Here, the Ne signal and the G signal are obtained by arranging projections (teeth) provided around a rotor that rotates at half the speed of a crankshaft provided in the engine distributor in proximity to the rotor. This is a pulse signal generated each time it passes through the electromagnetic pickup position. An arbitrary pulse signal can be generated by setting the shape of the teeth on the outer periphery of each rotor.

【００３６】図６は、４サイクル４気筒機関の場合のＮ
ｅ信号とＧ信号とクランク回転角との関係の一例を示
す。図６の例では、Ｎｅ信号用ロータの周囲には５°毎
（クランク回転角にして１０°毎）に回転パルス発生用
の歯が設けられており、さらに、第４気筒と第１気筒の
圧縮上死点（クランク角３６０°回転相当位置）に相当
する位置には気筒判別のために、歯数２枚に相当する欠
歯部分が設けられている。従って、Ｎｅ信号はクランク
回転角１０°毎のパルス信号と１回転（クランク回転角
７２０°）当たり２回の欠歯信号から構成される（図６
参照）。FIG. 6 shows N in the case of a four-cycle four-cylinder engine.
4 shows an example of a relationship among an e signal, a G signal, and a crank rotation angle. In the example of FIG. 6, teeth for generating rotation pulses are provided at every 5 ° (every 10 ° in crank rotation angle) around the Ne signal rotor. A missing tooth portion corresponding to two teeth is provided at a position corresponding to the compression top dead center (a position corresponding to a 360 ° rotation of the crank angle) for cylinder identification. Therefore, the Ne signal is composed of a pulse signal for every 10 ° of the crank rotation angle and two missing tooth signals for one rotation (720 ° of the crank rotation angle) (FIG. 6).
reference).

【００３７】また、Ｇ信号は、図６に示すように、ロー
レベルの信号とハイレベルの信号とが組み合わされた波
形とされ、Ｎｅ信号とＧ信号との組合せにより以下の方
法で各気筒の圧縮上死点の判定が可能になるようにされ
ている。すなわち、図６において、先ずＮｅ信号の欠歯
信号が入力されている場合には、第４または第１気筒が
圧縮上死点近傍にあることを意味し、さらにＧ信号がロ
ーレベルであれば第１気筒が（図６、）、ハイレベル
であれば第４気筒が（図６、）が、それぞれ圧縮上死
点近傍にあることが判定される。As shown in FIG. 6, the G signal has a waveform in which a low-level signal and a high-level signal are combined, and the combination of the Ne signal and the G signal causes the following method to be applied to each cylinder. The compression top dead center can be determined. That is, in FIG. 6, first, when the missing tooth signal of the Ne signal is input, it means that the fourth or first cylinder is near the compression top dead center, and if the G signal is low level, If the first cylinder (FIG. 6) is at a high level, it is determined that the fourth cylinder (FIG. 6) is near the compression top dead center, respectively.

【００３８】また、Ｎｅ信号の欠歯信号が入力されてい
ない場合には、Ｇ信号がローレベルからハイレベルに変
化するまでに入力したＮｅパルスの数が２より大きく４
以下（２＜Ｎｅ≦４）である場合（図６、）には第３
気筒が、また、Ｇ信号がローレベルからハイレベルに変
化するまでに入力したＮｅパルスの数が２以下で有る場
合には（図６、）第２気筒がそれぞれ圧縮上死点近傍
にあることが判定される。When the missing signal of the Ne signal is not input, the number of Ne pulses input before the G signal changes from low level to high level is larger than 2 and 4
In the following (2 <Ne ≦ 4) (FIG. 6), the third
If the number of Ne pulses input to the cylinder before the G signal changes from low level to high level is 2 or less (FIG. 6), the second cylinder must be near the compression top dead center. Is determined.

【００３９】この場合、図５ステップ５０９では上記に
より、Ｎｅ信号とＧ信号とから機関停止時に圧縮上死点
近傍にある気筒を判別し、この気筒に減圧のための燃料
噴射を行うようにする。これにより、噴射された燃料は
機関停止後も気筒内に留まり、大気に放出されることが
ないので点火プラグによる点火を行わずに未燃燃料の大
気放出が防止される。また、機関再始動時には上記気筒
内には燃料が確実に存在することになるため、機関再始
動が容易になる利点がある。In this case, in step 509 in FIG. 5, the cylinder located near the compression top dead center when the engine is stopped is determined from the Ne signal and the G signal, and fuel injection for pressure reduction is performed to this cylinder. . As a result, the injected fuel remains in the cylinder even after the engine is stopped and is not released to the atmosphere, so that the unburned fuel is prevented from being released to the atmosphere without being ignited by the ignition plug. Further, when the engine is restarted, the fuel is surely present in the cylinder, so that there is an advantage that the engine can be easily restarted.

【００４０】なお、図５の実施例では、イグニッション
スイッチがＯＦＦにされてから機関冷却水温ＴＨＷと外
気温ＴＡＴＭとに基づいて減圧のための燃料噴射が必要
か否かを判定しているが（図５、ステップ５０３、５０
５）、機関運転中に一定時間毎に実行される別のルーチ
ンで常時ＴＨＷとＴＡＴＭとに基づいて機関停止時の減
圧のための燃料噴射が必要か否かを判断するようにして
もよい。この場合、減圧のための燃料噴射が必要とされ
ない場合には、イグニッションスイッチＯＦＦと同時に
ＥＣＵ２０の電源をＯＦＦにして、燃料噴射が必要な場
合にのみＥＣＵ２０の電源ＯＦＦを遅延させて図５、ス
テップ５０７から５１５を実行するようにすれば良い。In the embodiment of FIG. 5, it is determined whether fuel injection for pressure reduction is necessary based on the engine cooling water temperature THW and the outside air temperature TATM after the ignition switch is turned off. FIG. 5, steps 503, 50
5) Alternatively, it may be determined whether fuel injection for pressure reduction when the engine is stopped is necessary based on THW and TATM in another routine that is executed at regular intervals during engine operation. In this case, when the fuel injection for pressure reduction is not required, the power of the ECU 20 is turned off at the same time as the ignition switch is turned off, and the power OFF of the ECU 20 is delayed only when the fuel injection is necessary. Steps 507 to 515 may be executed.

【００４１】また、図５の実施例では、冷却水温度ＴＨ
Ｗと外気温ＴＡＴＭの限界値ＴｅとＴａとはそれぞれ一
定値としている。しかし、機関停止時のデリバリパイプ
３内の燃料圧力が高ければ限界値Ｔｅ、Ｔａは低くなる
ため、予め図３に相当する関係を機関停止時の燃料油圧
力の値を変えて実験等により求めておき、機関停止時に
燃圧センサ３１で検出したデリバリパイプ３内の圧力に
応じて限界値Ｔｅ、Ｔａを求めるようにしてもよい。In the embodiment shown in FIG. 5, the cooling water temperature TH
W and the limit values Te and Ta of the outside air temperature TATM are constant values. However, if the fuel pressure in the delivery pipe 3 when the engine is stopped is high, the limit values Te and Ta are low. Therefore, the relationship corresponding to FIG. 3 is determined in advance by experiments and the like while changing the value of the fuel oil pressure when the engine is stopped. In addition, the limit values Te and Ta may be obtained according to the pressure in the delivery pipe 3 detected by the fuel pressure sensor 31 when the engine is stopped.

【００４２】[0042]

【発明の効果】請求項１に記載の本発明によれば、燃料
噴射弁の駆動ソレノイドやリターンスプリングを大型化
したり、燃料油をタンクに戻すリターン通路を設けるこ
となく簡易な方法で機関停止後の燃料圧力上昇による問
題を解決することができる。According to the first aspect of the present invention, after the engine is stopped by a simple method without increasing the size of the drive solenoid or return spring of the fuel injection valve or providing a return passage for returning fuel oil to the tank. The problem caused by the increase in the fuel pressure can be solved.

【００４３】さらに、請求項２に記載の本発明によれ
ば、吸気弁と排気弁との両方が閉弁している気筒にのみ
機関停止後の燃料噴射を行うようにしたことにより、請
求項１の効果に加え、エバポエミッションの悪化を防止
するとともに、機関再始動を容易にすることができる効
果が得られる。[0043] Further, according to the present invention described in claim 2, by both the intake valve and the exhaust valve is to perform the fuel injection after only the engine stop cylinder is closed, claim In addition to the effect of 1, the effect of preventing the deterioration of the evaporative emission and facilitating the restart of the engine is obtained.

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

【図１】本発明の実施例を説明する図である。FIG. 1 is a diagram illustrating an embodiment of the present invention.

【図２】機関停止後の燃料油圧力の上昇を説明する図で
ある。FIG. 2 is a diagram illustrating an increase in fuel oil pressure after an engine stop.

【図３】機関停止後の燃料油の最大到達圧力を示す図で
ある。FIG. 3 is a diagram showing a maximum ultimate pressure of fuel oil after an engine stop.

【図４】機関停止時の燃料噴射量の設定を示す図であ
る。FIG. 4 is a diagram showing setting of a fuel injection amount when the engine is stopped.

【図５】図１の実施例の減圧制御を示すフローチャート
の一例である。FIG. 5 is an example of a flowchart showing pressure reduction control of the embodiment in FIG. 1;

【図６】機関停止後に燃料噴射を行う気筒の判別方法を
説明する図である。FIG. 6 is a diagram illustrating a method of determining a cylinder for performing fuel injection after the engine is stopped.

【符号の説明】 １…燃料噴射弁 ３…デリバリパイプ ５…高圧ダイヤフラムポンプ ７…燃料タンク ９…フィードポンプ ２０…エンジン制御回路（ＥＣＵ）[Description of Signs] 1 ... Fuel injection valve 3 ... Delivery pipe 5 ... High-pressure diaphragm pump 7 ... Fuel tank 9 ... Feed pump 20 ... Engine control circuit (ECU)

───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) F02D 45/00 345 F02D 41/22 325 F02M 37/20 F02M 55/02 350 F02P 5/15 ──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. 7 , DB name) F02D 45/00 345 F02D 41/22 325 F02M 37/20 F02M 55/02 350 F02P 5/15

Claims (2)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】 加圧燃料が供給される燃料通路と、 前記燃料通路内の燃料を内燃機関の気筒内に噴射する燃
料噴射弁と、 前記燃料噴射弁の燃料噴射動作を制御する制御手段とを
備えた内燃機関の燃料噴射制御装置において、 機関停止時の機関冷却水温度と外気温度とに基づいて、
機関停止後の温度上昇による前記燃料通路内の燃料圧力
の最大到達値を推定する推定手段を備え、 前記制御手段は、前記推定された圧力最大到達値が予め
定めた所定値以上の場合、機関停止直後に前記燃料噴射
弁からの燃料噴射を行って前記燃料通路内の圧力を低下
させることを特徴とする内燃機関の燃料噴射制御装置。A fuel passage for supplying pressurized fuel; a fuel injection valve for injecting fuel in the fuel passage into a cylinder of an internal combustion engine; and control means for controlling a fuel injection operation of the fuel injection valve. In the fuel injection control device for an internal combustion engine provided with: based on the engine cooling water temperature and the outside air temperature when the engine is stopped,
Estimating means for estimating a maximum value of a fuel pressure in the fuel passage due to a temperature rise after the engine is stopped, wherein the control means is configured to control the engine when the estimated maximum pressure value is equal to or greater than a predetermined value. A fuel injection control device for an internal combustion engine, wherein fuel injection from the fuel injection valve is performed immediately after stopping to reduce the pressure in the fuel passage. 【請求項２】 前記制御手段は、前記機関停止時に前記
燃料噴射弁からの燃料噴射を行うときに、吸気弁と排気
弁との両方が閉弁している気筒の燃料噴射弁からのみ燃
料噴射を行う請求項１に記載の燃料噴射弁制御装置。2. The fuel injection system according to claim 2, wherein when the engine is stopped, the control unit performs fuel injection only from a fuel injection valve of a cylinder in which both the intake valve and the exhaust valve are closed. The fuel injection valve control device according to claim 1, wherein the control is performed.
JP04412994A 1994-03-15 1994-03-15 Fuel injection control device Expired - Fee Related JP3289472B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP04412994A JP3289472B2 (en) 1994-03-15 1994-03-15 Fuel injection control device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP04412994A JP3289472B2 (en) 1994-03-15 1994-03-15 Fuel injection control device

Publications (2)

Publication Number Publication Date
JPH07253041A JPH07253041A (en) 1995-10-03
JP3289472B2 true JP3289472B2 (en) 2002-06-04

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ID=12683014

Family Applications (1)

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Cited By (2)

* Cited by examiner, † Cited by third party
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DE102004014400B4 (en) * 2003-09-22 2007-11-29 Mitsubishi Denki K.K. Fuel pressure control device for cylinder injection combustion engine
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DE10343758B4 (en) * 2003-09-22 2015-02-19 Robert Bosch Gmbh Method for limiting the pressure increase in a high-pressure fuel system after stopping an internal combustion engine
JP4577616B2 (en) * 2005-11-01 2010-11-10 トヨタ自動車株式会社 Control device for internal combustion engine
JP4922906B2 (en) * 2007-12-10 2012-04-25 日立オートモティブシステムズ株式会社 High pressure fuel supply device and control device for internal combustion engine
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DE102004014400B4 (en) * 2003-09-22 2007-11-29 Mitsubishi Denki K.K. Fuel pressure control device for cylinder injection combustion engine
JP2009191853A (en) * 2009-06-01 2009-08-27 Hitachi Ltd High pressure fuel supply device for internal combustion engine

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