JP2015183622A - Internal combustion engine fuel injection system - Google Patents

Internal combustion engine fuel injection system Download PDF

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JP2015183622A
JP2015183622A JP2014061935A JP2014061935A JP2015183622A JP 2015183622 A JP2015183622 A JP 2015183622A JP 2014061935 A JP2014061935 A JP 2014061935A JP 2014061935 A JP2014061935 A JP 2014061935A JP 2015183622 A JP2015183622 A JP 2015183622A
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fuel
pressure
cylinder
fuel injection
internal combustion
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JP6395026B2 (en
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礼俊 松永
Noritoshi Matsunaga
礼俊 松永
山口　康夫
Yasuo Yamaguchi
康夫 山口
村田　真一
Shinichi Murata
真一 村田
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Mitsubishi Motors Corp
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Mitsubishi Motors Corp
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Priority to JP2014061935A priority Critical patent/JP6395026B2/en
Priority to CN201580015219.1A priority patent/CN106460686B/en
Priority to EP15768804.5A priority patent/EP3109443B1/en
Priority to PCT/JP2015/058783 priority patent/WO2015146930A1/en
Priority to US15/115,558 priority patent/US10450989B2/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/3094—Controlling fuel injection the fuel injection being effected by at least two different injectors, e.g. one in the intake manifold and one in the cylinder
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02N—STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
    • F02N11/00—Starting of engines by means of electric motors
    • F02N11/08—Circuits or control means specially adapted for starting of engines
    • F02N11/0814—Circuits or control means specially adapted for starting of engines comprising means for controlling automatic idle-start-stop
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/06—Fuel or fuel supply system parameters
    • F02D2200/0602—Fuel pressure
    • 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
    • Y02T10/40—Engine management systems

Abstract

PROBLEM TO BE SOLVED: To ensure prompt restart after idling stop and prevent degradations in drivability and NVH and the like immediately after restart by eliminating the occurrence of knocking at a time of the restart.SOLUTION: An internal combustion engine fuel injection system comprises: a high-pressure fuel distribution pipe 54 injecting fuel into cylinders 12a to 12d; a low-pressure fuel supply pipe 42 injecting the fuel to an intake manifold 14; and a fuel pressure sensor 56 measuring a fuel pressure of the high-pressure fuel distribution pipe 54. An ECU 60 includes an idling stop/start unit 68 stopping an engine 10 when an idling stop condition is satisfied and restarting the engine 10 when the idling stop condition is canceled; and a fuel injection control unit 70 selecting the cylinder having a cylinder internal pressure at which the fuel remaining in the high-pressure fuel distribution pipe 54 in response to a measurement value of the fuel pressure sensor 56, and injecting the fuel from the high-pressure fuel distribution pipe 54 into the selected cylinder before a crankshaft 32 starts rotating by a starter 34.

Description

本発明は、車両の一時停止時に内燃機関のアイドリングを強制的に停止するいわゆるアイドルストップ機能を有する内燃機関の燃料噴射装置に関する。   The present invention relates to a fuel injection device for an internal combustion engine having a so-called idle stop function for forcibly stopping idling of the internal combustion engine when the vehicle is temporarily stopped.

車両に装備された内燃機関の燃料噴射装置として、筒内に燃料を噴射するための筒内インジェクタと吸気ポート内に燃料を噴射するための吸気通路インジェクタとを備え、運転状態に応じて筒内インジェクタからの燃料噴射と吸気通路インジェクタからの燃料噴射とを制御する多点噴射式燃料噴射装置が知られている。
多点噴射式燃料噴射装置を用いることで、アクセルレスポンスや燃費を向上させ、排ガスの清浄化を可能にしている。この燃料噴射装置は、低負荷低回転領域では、吸気通路に燃料を噴射することで、吸気と燃料の混合特性を良くして着火性を良くし、高負荷高回転領域では、吸気通路インジェクタからの燃料噴射と筒内インジェクタからの燃料噴射とを併用するようにしている。 As a fuel injection device for an internal combustion engine equipped in a vehicle, it is provided with an in-cylinder injector for injecting fuel into a cylinder and an intake passage injector for injecting fuel into an intake port, A multi-point injection type fuel injection device that controls fuel injection from an injector and fuel injection from an intake passage injector is known.
By using a multi-point fuel injection device, accelerator response and fuel efficiency are improved, and exhaust gas can be purified. This fuel injection device injects fuel into the intake passage in the low load and low rotation region, thereby improving the mixing characteristics of the intake air and the fuel and improving the ignitability, and in the high load and high rotation region, from the intake passage injector. The fuel injection and the fuel injection from the in-cylinder injector are used in combination.

また、車両の一時停止時にエンジンのアイドリングを強制的に停止するいわゆるアイドルストップ機能を付与して燃費を向上させる試みがなされている。
車両がエンジンを停止するときは、運転を終了する場合と、再始動を前提とした一時停止の場合とがある。前者は、イグニッションキーがオフとされる。一方、後者は、車速が零となり、ブレーキの踏込みがあり、アクセル操作量が零であり、かつレバーが運転レンジに設定されている等の条件が成立する。アイドルストップ機能を有する車両では、かかる条件が成立したとき、ＥＣＵなどに内蔵されたアイドルストップ・スタート部が作動し、エンジンをストップさせる。 Attempts have also been made to improve fuel efficiency by providing a so-called idle stop function that forcibly stops engine idling when the vehicle is temporarily stopped.
When the vehicle stops the engine, there are a case where the driving is ended and a case where the vehicle is temporarily stopped on the assumption of restart. In the former case, the ignition key is turned off. On the other hand, in the latter, conditions such that the vehicle speed is zero, the brake is depressed, the accelerator operation amount is zero, and the lever is set to the driving range are satisfied. In a vehicle having an idle stop function, when such a condition is satisfied, an idle stop / start unit built in the ECU or the like operates to stop the engine.

特許文献１には、筒内インジェクタを有する筒内燃料供給路と、吸気通路インジェクタを有する吸気通路燃料供給路と、アイドルストップ・スタート手段とを有する内燃機関を備えたハイブリッド車が開示されている。このハイブリッド車は、アイドルストップ時に前記筒内燃料供給路のリリーフ弁を閉じて燃圧（燃料圧力）を高く保持する手段が開示されている。こうして、アイドルストップ条件解除後のエンジン再始動時に、前記筒内燃料供給路から気筒内に燃料を噴射することで、円滑な始動特性の確保と、排気清浄の悪化防止とを両立させることを目的としている。   Patent Document 1 discloses a hybrid vehicle including an internal combustion engine having an in-cylinder fuel supply passage having an in-cylinder injector, an intake passage fuel supply passage having an intake passage injector, and idle stop / start means. . This hybrid vehicle discloses means for keeping the fuel pressure (fuel pressure) high by closing the relief valve of the in-cylinder fuel supply path at the time of idling stop. Thus, when restarting the engine after the release of the idle stop condition, the fuel is injected into the cylinder from the in-cylinder fuel supply path, thereby ensuring both smooth start characteristics and prevention of deterioration of exhaust purification. It is said.

特開２００６−２５８０３２号公報JP 2006-258032 A

多点噴射式燃料噴射装置を備え、アイドルストップ・スタート手段を有する車両においては、アイドルストップ後の迅速な再始動と、排ガス性状や燃費等の面で再始動後の最適化運転を両立させる必要がある。
アイドルストップによるエンジン停止中に、吸気通路の吸気圧は大気圧に変化する。そのため、再始動時の初爆から数回の燃焼サイクルが行われる間は吸入空気量が多くなり、実際の圧縮圧力は高くなる傾向にある。これによって、吸気温度が高い場合やエンジン温度が高い場合、ノッキングが発生しやすくなり、ノッキングの発生によって、始動直後のドライバビリティやＮＶＨ（ノイズ・バイブレーション・ハーシュネス）が悪化するという問題がある。 For vehicles equipped with a multi-point injection fuel injection system and having an idle stop / start means, it is necessary to achieve both rapid restart after idle stop and optimized operation after restart in terms of exhaust gas properties, fuel consumption, etc. There is.
While the engine is stopped due to idle stop, the intake pressure in the intake passage changes to atmospheric pressure. Therefore, the intake air amount increases and the actual compression pressure tends to increase during several combustion cycles from the initial explosion at the time of restart. As a result, when the intake air temperature is high or the engine temperature is high, knocking is likely to occur, and there is a problem that drivability and NVH (noise vibration harshness) immediately after start-up deteriorate due to the occurrence of knocking.

また、エンジンが停止中は燃料ポンプが作動しないので、燃料供給路の燃圧が低下しており、そのため、気筒内への燃料噴射が遅れ、エンジンの再始動時迅速始動ができない場合がある。   Further, since the fuel pump does not operate while the engine is stopped, the fuel pressure in the fuel supply path is lowered, and therefore, fuel injection into the cylinder is delayed, and there is a case where the engine cannot be started quickly when the engine is restarted.

特許文献１には、アイドルストップ後の再始動時に、ノッキングの発生を防止する手段は開示されていない。また、アイドルストップ後の再始動時に、筒内燃料供給路の燃圧を計測せずに、気筒内へ燃料を噴射するので、圧力が比較的高い状態の気筒へは燃料を噴射できないおそれがある。そのため、迅速な再始動ができないおそれがある。   Patent Document 1 does not disclose means for preventing the occurrence of knocking at the time of restart after idle stop. In addition, since fuel is injected into the cylinder without measuring the fuel pressure in the in-cylinder fuel supply path at the restart after the idle stop, there is a possibility that the fuel cannot be injected into the cylinder in a relatively high pressure state. Therefore, there is a possibility that quick restart cannot be performed.

本発明は、前記の問題点に鑑みなされたものであり、アイドルストップ後の迅速な再始動と、再始動時にノッキングの発生をなくすことで、再始動直後のドライバビリティやＮＶＨの悪化を防止することを目的とする。   The present invention has been made in view of the above-described problems, and prevents deterioration of drivability and NVH immediately after restart by eliminating the occurrence of knocking during quick restart after idle stop and restart. For the purpose.

本発明は、内燃機関の気筒内に燃料を噴射する第１燃料噴射手段と、内燃機関の吸気通路に燃料を噴射する第２燃料噴射手段と、内燃機関を自動で再始動する自動再始動手段を有する内燃機関の燃料噴射装置に適用される。
そして、前記目的を達成するため、本発明の燃料噴射装置は、第１燃料噴射手段の燃料圧力を計測する燃圧センサと、該燃圧センサの計測値に応じて第１燃料噴射手段に残留した燃料を噴射可能な筒内圧を有する気筒を選定し、該選定した気筒に第１燃料噴射手段に残留した燃料を噴射させる燃料噴射制御手段とを備えている。 The present invention relates to a first fuel injection means for injecting fuel into a cylinder of an internal combustion engine, a second fuel injection means for injecting fuel into an intake passage of the internal combustion engine, and an automatic restart means for automatically restarting the internal combustion engine. The present invention is applied to a fuel injection device for an internal combustion engine.
In order to achieve the above object, the fuel injection device of the present invention includes a fuel pressure sensor for measuring the fuel pressure of the first fuel injection means, and the fuel remaining in the first fuel injection means in accordance with the measured value of the fuel pressure sensor. And a fuel injection control means for selecting a cylinder having an in-cylinder pressure capable of injecting fuel and injecting fuel remaining in the first fuel injection means into the selected cylinder.

前述のように、アイドルストップによるエンジン停止中に、吸気通路の吸気圧は大気圧に変化する。そのため、再始動時の初爆から数回の燃焼サイクルが行われる間は吸入空気量が多くなり、実際の圧縮圧力は高くなる傾向にある。
そのため、本発明では、前記燃料噴射制御手段によって、再始動時に第１燃料噴射手段による気筒内への燃料噴射のみを行う。その際、燃圧センサで第１燃料噴射手段に残留した燃料の燃圧を計測し、第１燃料噴射手段に残留した燃料を噴射可能な筒内圧を有する気筒を選定し、この選定した気筒に第１燃料噴射手段に残留した燃料を噴射させる。 As described above, the intake pressure in the intake passage changes to atmospheric pressure while the engine is stopped due to idle stop. Therefore, the intake air amount increases and the actual compression pressure tends to increase during several combustion cycles from the initial explosion at the time of restart.
Therefore, in the present invention, the fuel injection control means performs only fuel injection into the cylinder by the first fuel injection means at the time of restart. At that time, the fuel pressure of the fuel remaining in the first fuel injection means is measured by the fuel pressure sensor, a cylinder having an in-cylinder pressure capable of injecting the fuel remaining in the first fuel injection means is selected, and the first cylinder is selected as the selected cylinder. The remaining fuel is injected into the fuel injection means.

このように、第１燃料噴射手段に残留している燃料を気筒内に噴射し、気筒に供給される吸気量を抑えつつ、噴射された燃料の冷却作用で気筒内を冷却できる。そのため、気筒内の圧縮圧力の増加をなくし、ノッキングの発生を防止できるので、始動直後のドライバビリティやＮＶＨの悪化、及び排ガス性状の悪化を防止できる。   In this way, the fuel remaining in the first fuel injection means is injected into the cylinder, and the inside of the cylinder can be cooled by the cooling action of the injected fuel while suppressing the amount of intake air supplied to the cylinder. Therefore, the increase in the compression pressure in the cylinder can be eliminated and the occurrence of knocking can be prevented, so that it is possible to prevent drivability immediately after starting, deterioration of NVH, and deterioration of exhaust gas properties.

また、第１燃料噴射手段からの燃料噴射によって空燃比を低く抑えることができるので、着火性能が良くなると共に、燃料ポンプの稼働を待つことなく、気筒への迅速な燃料供給が可能となり、これによって、アイドルストップ後の迅速な再始動が可能となる。
さらに、第１燃料供給路の燃圧を計測すると共に、燃料噴射制御手段によって、第１燃料供給路に残留した燃料を噴射可能な筒内圧を有する気筒を選定し、この選定した気筒に燃料を噴射させることで、気筒内への燃料噴射を確実に行うことができる。 Further, since the air-fuel ratio can be kept low by the fuel injection from the first fuel injection means, the ignition performance is improved and the fuel can be quickly supplied to the cylinder without waiting for the operation of the fuel pump. Thus, a quick restart after an idle stop is possible.
Further, the fuel pressure in the first fuel supply passage is measured, and a cylinder having an in-cylinder pressure capable of injecting fuel remaining in the first fuel supply passage is selected by the fuel injection control means, and fuel is injected into the selected cylinder. By doing so, fuel injection into the cylinder can be reliably performed.

気筒内燃料噴射による再始動後、数回の燃焼サイクルを経て吸気圧が低下し、かつ吸気温が低下したら、ノッキングが発生するおそれがなくなるため、第２燃料供給路から燃料噴射に切り換える。あるいは第１燃料供給路からの燃料噴射と第２燃料供給路からの燃料噴射とを併用してもよい。   After the restart by in-cylinder fuel injection, when the intake pressure decreases through several combustion cycles and the intake air temperature decreases, there is no risk of knocking, so the second fuel supply path is switched to fuel injection. Alternatively, fuel injection from the first fuel supply path and fuel injection from the second fuel supply path may be used in combination.

本発明の一実施態様は、前記燃料噴射制御手段により、スタータによるクランク軸の回転が開始される前に第１燃料噴射手段に残留した燃料を噴射させるものである。
このように、クランク軸の回転開始前（即ち、ピストンの動作開始前）の筒内圧が低い気筒に第１燃料供給路から燃料を噴射できるので、燃料の噴射が容易になる。 In one embodiment of the present invention, the fuel injection control means injects the remaining fuel in the first fuel injection means before the start of rotation of the crankshaft by the starter.
Thus, fuel can be injected from the first fuel supply path into the cylinder having a low in-cylinder pressure before the rotation of the crankshaft is started (that is, before the operation of the piston is started).

本発明の別な一実施態様は、前記燃料噴射制御手段により、第１燃料噴射手段の燃料圧力が第１の閾値以上であるとき、圧縮行程で停止した第１の気筒を選定し、この第１の気筒に第１燃料噴射手段に残留した燃料を噴射させる。
第１燃料噴射手段の燃料圧力が第１の閾値より低圧の第２の閾値以上であるとき、吸気行程（好ましくは、吸気行程後半）又は圧縮行程前半の領域で停止した第２の気筒を選定し、この第２の気筒に第１燃料噴射手段に残留した燃料を噴射させる。
また、第１噴射手段の燃料圧力が第２の閾値未満のとき、吸気行程直前又は吸気行程前半の領域で停止した第３の気筒を選定し、この第３の気筒に第１燃料噴射手段に残留した燃料を噴射させる。 In another embodiment of the present invention, the fuel injection control means selects the first cylinder stopped in the compression stroke when the fuel pressure of the first fuel injection means is equal to or higher than the first threshold value. Fuel remaining in the first fuel injection means is injected into one cylinder.
When the fuel pressure of the first fuel injection means is equal to or higher than the second threshold value lower than the first threshold value, the second cylinder stopped in the region of the intake stroke (preferably, the latter half of the intake stroke) or the first half of the compression stroke is selected. Then, the fuel remaining in the first fuel injection means is injected into the second cylinder.
Further, when the fuel pressure of the first injection means is less than the second threshold value, a third cylinder stopped immediately before the intake stroke or in the first half of the intake stroke is selected, and this third cylinder is used as the first fuel injection means. Inject remaining fuel.

第１の閾値及び第２の閾値は、エンジンの再始動と同時に燃料が噴射される気筒の筒内圧との関係で燃料噴射を可能とする燃圧を目安として設定される。
このように、アイドルストップ時、第１燃料噴射手段に残留した燃料の燃圧が第１の閾値以上のとき、圧縮行程で停止した気筒に燃料を噴射させることで、速やかに燃焼行程に移行でき、迅速な再始動が可能になる。
また、残留燃料の燃圧が第１の閾値に達していないとき、吸気行程（好ましくは吸気行程後半）又は圧縮行程前半の領域で停止した気筒に残留燃料を噴射させることで、気筒内への燃料噴射を確実に行うことができると共に、排気行程で停止した気筒への燃料噴射を避けることができ、排ガス性状の悪化を防止できる。 The first threshold value and the second threshold value are set based on the fuel pressure that enables fuel injection in relation to the in-cylinder pressure of the cylinder into which fuel is injected simultaneously with the restart of the engine.
Thus, at the time of idling stop, when the fuel pressure of the fuel remaining in the first fuel injection means is equal to or higher than the first threshold value, the fuel can be quickly transferred to the combustion stroke by injecting the fuel into the cylinder stopped in the compression stroke, Rapid restart is possible.
Further, when the fuel pressure of the residual fuel does not reach the first threshold value, the residual fuel is injected into the cylinder stopped in the region of the intake stroke (preferably the latter half of the intake stroke) or the first half of the compression stroke, so that the fuel into the cylinder is injected. In addition to reliably performing injection, it is possible to avoid fuel injection into the cylinder stopped in the exhaust stroke, and to prevent deterioration of exhaust gas properties.

本発明のさらに別な一実施態様は、前記燃料噴射制御手段により、第１燃料噴射手段の燃料圧力が第２の閾値未満のときは、少なくとも第２の燃料噴射手段からの噴射を行うものである。
これによって、第１燃料噴射手段の燃圧が低くても気筒への燃料噴射を確実に行うことができ、迅速な再始動が可能になる。 In another embodiment of the present invention, when the fuel pressure of the first fuel injection means is less than the second threshold, the fuel injection control means performs injection from at least the second fuel injection means. is there.
As a result, even if the fuel pressure of the first fuel injection means is low, fuel can be reliably injected into the cylinder, and quick restart is possible.

本発明によれば、アイドルストップ後の再始動時に、第１燃料供給路から燃料を噴射させることで、ノッキングの発生をなくした迅速な再始動が可能になり、始動直後の良好なドライバビリティを可能にすると共に、排ガス性状やＮＶＨの悪化を防止できる。   According to the present invention, at the time of restart after idle stop, fuel can be injected from the first fuel supply path, thereby enabling quick restart without the occurrence of knocking, and good drivability immediately after starting. While making it possible, it is possible to prevent deterioration of exhaust gas properties and NVH.

本発明の一実施形態に係る車両用エンジンの燃料噴射装置の概略構成図である。It is a schematic block diagram of the fuel-injection apparatus of the vehicle engine which concerns on one Embodiment of this invention. 前記燃料噴射装置の平面視概略構成図である。It is a planar view schematic block diagram of the said fuel injection apparatus. 前記燃料噴射装置のアイドルストップ条件解除後の作動手順を示すフロー図である。It is a flowchart which shows the operation | movement procedure after idle stop condition cancellation | release of the said fuel injection apparatus. 前記燃料噴射装置の各気筒の燃焼サイクルを示す図表である。It is a graph which shows the combustion cycle of each cylinder of the said fuel injection apparatus. 前記燃料噴射装置の各気筒の停止時クランク角を示す図表である。It is a graph which shows the crank angle at the time of a stop of each cylinder of the fuel injection device.

以下、本発明を図に示した実施形態を用いて詳細に説明する。但し、この実施形態に記載されている構成部品の寸法、材質、形状、その相対配置などは特に特定的な記載がない限り、この発明の範囲をそれのみに限定する趣旨ではない。   Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to that unless otherwise specified.

次に、本発明の一実施形態に係る車両用エンジンの燃料噴射装置を図１〜図５に基づいて説明する。図１及び図２において、車両に搭載されたガソリン駆動エンジン（以下、「エンジン」という。）１０は、複数の、即ち４個の気筒１２ａ〜１２ｄを有した直列４気筒エンジンであり、各気筒には夫々吸気マニホールド１４及び排気マニホールド１６が接続され、吸気マニホールド１４はサージタンク２２に接続されている。吸気マニホールド１４の出口には吸気弁１８が設けられ、排気マニホールド１６の入口には排気弁２０が設けられている。サージタンク２２には、吸気の圧力を計測する吸気圧センサ（ＭＡＰセンサ）２４、及び吸気の温度を計測する吸気温センサ２６が設けられている。   Next, a fuel injection device for a vehicle engine according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2, a gasoline-driven engine (hereinafter referred to as “engine”) 10 mounted on a vehicle is an in-line four-cylinder engine having a plurality of, that is, four cylinders 12a to 12d. Are connected to an intake manifold 14 and an exhaust manifold 16, respectively. The intake manifold 14 is connected to a surge tank 22. An intake valve 18 is provided at the outlet of the intake manifold 14, and an exhaust valve 20 is provided at the inlet of the exhaust manifold 16. The surge tank 22 is provided with an intake pressure sensor (MAP sensor) 24 that measures the pressure of intake air and an intake air temperature sensor 26 that measures the temperature of intake air.

各気筒１２ａ〜１２ｄの内部には燃焼室ｃの燃焼によって往復動するピストン２８が設けられ、各気筒１２ａ〜１２ｄの下部には、クランク軸３２を収容したクランク室３０が設けられている。クランク室３０の外側には、エンジン始動時にクランク軸３２を回転させるスタータ３４、クランク角を計測するクランク角センサ３６及びクランク軸３２の回転数を計測する回転数センサ３７が設けられている。   A piston 28 that reciprocates due to combustion in the combustion chamber c is provided inside each cylinder 12a to 12d, and a crank chamber 30 that houses a crankshaft 32 is provided below each cylinder 12a to 12d. Outside the crank chamber 30, a starter 34 that rotates the crankshaft 32 when the engine is started, a crank angle sensor 36 that measures the crank angle, and a rotation speed sensor 37 that measures the rotation speed of the crankshaft 32 are provided.

次に、エンジン１０の燃料供給系を説明する。燃料タンク３８に貯留された燃料は、燃料タンク３８に内蔵された低圧燃料ポンプ４０によって、低圧燃料供給管４２に吐出される。低圧燃料供給管４２は、低圧燃料分配管４８を介して吸気マニホールド１４の個々の吸気通路に接続されている。低圧燃料供給管（低圧デリバリーパイプ）４２と吸気マニホールド１４の該吸気通路との接続部に夫々吸気通路インジェクタ４６が設けられている。
低圧燃料供給管４２及び吸気通路インジェクタ４６で低圧燃料系統（第２燃料噴射手段）を構成している。 Next, the fuel supply system of the engine 10 will be described. The fuel stored in the fuel tank 38 is discharged to a low-pressure fuel supply pipe 42 by a low-pressure fuel pump 40 built in the fuel tank 38. The low-pressure fuel supply pipes 42 are connected to individual intake passages of the intake manifold 14 via low-pressure fuel distribution pipes 48. An intake passage injector 46 is provided at a connection portion between the low pressure fuel supply pipe (low pressure delivery pipe) 42 and the intake passage of the intake manifold 14.
The low-pressure fuel supply pipe 42 and the intake passage injector 46 constitute a low-pressure fuel system (second fuel injection means).

低圧燃料供給管４２の一方の流路は、高圧燃料ポンプ５０を介して高圧燃料供給管５３及び高圧燃料分配管５４に接続されている。高圧燃料分配管５４は各気筒１２ａ〜１２ｄに接続され、各気筒との接続部に筒内インジェクタ４４が設けられている。
低圧燃料ポンプ４０によって低圧燃料供給管４２に吐出された燃料は、高圧燃料ポンプ５０に送られると共に、低圧燃料分配管４８を介して吸気マニホールド１４の各吸気通路に吸気通路インジェクタ４６を介して供給される。 One flow path of the low-pressure fuel supply pipe 42 is connected to a high-pressure fuel supply pipe 53 and a high-pressure fuel distribution pipe 54 via a high-pressure fuel pump 50. The high-pressure fuel distribution pipe 54 is connected to each cylinder 12a to 12d, and an in-cylinder injector 44 is provided at a connection portion with each cylinder.
The fuel discharged to the low-pressure fuel supply pipe 42 by the low-pressure fuel pump 40 is sent to the high-pressure fuel pump 50 and supplied to each intake passage of the intake manifold 14 via the low-pressure fuel distribution pipe 48 via the intake passage injector 46. Is done.

カム機構５２はクランク軸３２と連動して吸気弁１８及び排気弁２０を開閉駆動する。高圧燃料ポンプ５０は、カム機構５２と連動して高圧燃料分配管５４に燃料を供給すると共に、後述するＥＣＵ６０からの指令によってその燃料供給が制御される。高圧燃料ポンプ５０に送られた燃料は、高圧燃料ポンプ５０によって高圧となり、高圧燃料供給管５３及び高圧燃料分配管（高圧デリバリーパイプ）５４を介して各気筒１２ａ〜１２ｄに供給され、筒内インジェクタ４４から各気筒の燃焼室ｃに噴射される。高圧燃料分配管５４には、燃料圧力を計測する燃圧センサ５６が設けられている。
筒内インジェクタ４４、高圧燃料ポンプ５０、高圧燃料供給管５３及び高圧燃料分配管５４で高圧燃料系統（第１燃料噴射手段）を構成している。 The cam mechanism 52 opens and closes the intake valve 18 and the exhaust valve 20 in conjunction with the crankshaft 32. The high-pressure fuel pump 50 supplies fuel to the high-pressure fuel distribution pipe 54 in conjunction with the cam mechanism 52, and the fuel supply is controlled by a command from the ECU 60 described later. The fuel sent to the high-pressure fuel pump 50 becomes high pressure by the high-pressure fuel pump 50 and is supplied to each cylinder 12a to 12d via the high-pressure fuel supply pipe 53 and the high-pressure fuel distribution pipe (high-pressure delivery pipe) 54. 44 is injected into the combustion chamber c of each cylinder. The high-pressure fuel distribution pipe 54 is provided with a fuel pressure sensor 56 for measuring the fuel pressure.
The in-cylinder injector 44, the high-pressure fuel pump 50, the high-pressure fuel supply pipe 53, and the high-pressure fuel distribution pipe 54 constitute a high-pressure fuel system (first fuel injection means).

エンジン１０が搭載された車両には、車載バッテリ５８及びエンジン１０の駆動を制御するエンジン・コントロール・ユニット（ＥＣＵ）６０が設けられている。運転者がイグニッション・スィッチ６２を操作することで、ＥＣＵ６０が作動を開始する。ＥＣＵ６０の指令によって、車載バッテリ５８からリレー６４を介して低圧燃料ポンプ４０に電力が供給され、低圧燃料ポンプ４０が稼働する。また、ＥＣＵ６０の指令によって、点火プラグ６６、筒内インジェクタ４４及び吸気通路インジェクタ４６の作動が制御される。   A vehicle on which the engine 10 is mounted is provided with an in-vehicle battery 58 and an engine control unit (ECU) 60 that controls driving of the engine 10. When the driver operates the ignition switch 62, the ECU 60 starts operating. In response to a command from the ECU 60, electric power is supplied from the in-vehicle battery 58 to the low-pressure fuel pump 40 via the relay 64, and the low-pressure fuel pump 40 operates. Further, the operation of the spark plug 66, the in-cylinder injector 44, and the intake passage injector 46 is controlled by a command from the ECU 60.

ＥＣＵ６０には、アイドルストップ・スタート部６８及び燃料噴射制御部７０が内蔵されている。ＥＣＵ６０には、吸気圧センサ２４、吸気温センサ２６、クランク角センサ３６、回転数センサ３７及び燃圧センサ５６の計測値が入力される。
アイドルストップ・スタート部６８は、点火プラグ６６及びスタータ３４等の作動を制御し、車速が零となり、ブレーキの踏込みがあり、アクセル操作量が零であり、かつレバーが運転レンジに設定されている等のアイドルストップ条件が成立したとき、エンジン１０を停止する。また、アイドルストップ条件が解除されたとき、エンジン１０を再始動させる。 The ECU 60 includes an idle stop / start unit 68 and a fuel injection control unit 70. The ECU 60 receives measured values of the intake pressure sensor 24, the intake air temperature sensor 26, the crank angle sensor 36, the rotation speed sensor 37, and the fuel pressure sensor 56.
The idle stop / start unit 68 controls the operation of the spark plug 66, the starter 34, etc., the vehicle speed becomes zero, the brake is depressed, the accelerator operation amount is zero, and the lever is set to the driving range. When the idle stop condition such as is satisfied, the engine 10 is stopped. Further, when the idle stop condition is canceled, the engine 10 is restarted.

燃料噴射制御部７０は、アイドルストップ条件が成立してエンジン１０が停止し、その後、アイドルストップ条件が解除されたとき、再始動時に筒内インジェクタ４４、吸気通路インジェクタ４６及び点火プラグ６６の作動を制御する。   The fuel injection control unit 70 operates the in-cylinder injector 44, the intake passage injector 46, and the spark plug 66 during restart when the engine 10 is stopped when the idle stop condition is satisfied and then the idle stop condition is canceled. Control.

次に、図３により、アイドルストップ条件が成立し、アイドルストップ・スタート部６８によってエンジン１０が停止し、その後、アイドルストップ条件が解除されたとき、燃料噴射制御部７０の制御によってエンジン１０が再始動する動作手順を説明する。
図３において、まず、クランク角センサ３６により、各気筒１２ａ〜１２ｄが停止状態にあるときのクランク角を計測する(Ｓ１０)。図４に、クランク角と各気筒１２ａ〜１２ｄ（直列４気筒）の燃焼サイクル中の行程との相関関係を示す。点火順序は、１２ａ、１２ｃ、１２ｄ、１２ｂの順で点火される。 Next, according to FIG. 3, when the idle stop condition is satisfied, the engine 10 is stopped by the idle stop / start unit 68, and then the idle stop condition is released, the engine 10 is restarted by the control of the fuel injection control unit 70. The starting operation procedure will be described.
In FIG. 3, first, the crank angle when each cylinder 12a to 12d is stopped is measured by the crank angle sensor 36 (S10). FIG. 4 shows the correlation between the crank angle and the stroke in the combustion cycle of each of the cylinders 12a to 12d (in-line four cylinders). The ignition sequence is ignited in the order of 12a, 12c, 12d, and 12b.

次に、燃料噴射制御部７０で、燃圧センサ５６で計測された高圧燃料分配管５４の燃圧（エンジン再始動時の燃圧）が、予め設定された第１の閾値以上かどうかを判定する（Ｓ１２）。第１の閾値は、圧縮行程の領域で停止した気筒に高圧燃料分配管５４から燃料を噴射できる燃圧を目安に設定する。燃圧センサ５６の計測値が第１の閾値以上であれば、圧縮行程でピストン２８が停止した第１の気筒を選定し、この第１の気筒に高圧燃料分配管５４に残留している燃料をその燃圧を利用して筒内インジェクタ４４から噴射させる(Ｓ１４→Ｓ２２)。   Next, the fuel injection control unit 70 determines whether or not the fuel pressure of the high-pressure fuel distribution pipe 54 measured by the fuel pressure sensor 56 (fuel pressure at the time of engine restart) is equal to or higher than a preset first threshold value (S12). ). The first threshold value is set based on the fuel pressure at which fuel can be injected from the high-pressure fuel distribution pipe 54 into the cylinder stopped in the compression stroke region. If the measured value of the fuel pressure sensor 56 is equal to or greater than the first threshold value, the first cylinder in which the piston 28 is stopped in the compression stroke is selected, and the fuel remaining in the high-pressure fuel distribution pipe 54 is selected in the first cylinder. The fuel pressure is used to inject from the in-cylinder injector 44 (S14 → S22).

燃圧センサ５６の計測値が第１の閾値に達せず、かつ第１の閾値より低圧の第２の閾値以上であれば（Ｓ１６）、吸気行程後半又は圧縮行程前半の領域でピストン２８が停止した第２の気筒を選定する（Ｓ１８）。この第２の気筒に筒内インジェクタ４４から、高圧燃料分配管５４に残留している燃料をその燃圧を利用して噴射する(Ｓ２２)。第２の閾値は、第１の閾値より低い燃圧で、吸気行程後半又は圧縮行程前半の領域で停止した気筒に燃料を噴射可能な燃圧を目安に設定される。 If the measured value of the fuel pressure sensor 56 does not reach the first threshold value and is equal to or higher than the second threshold value lower than the first threshold value (S16), the piston 28 is stopped in the second half of the intake stroke or the first half of the compression stroke. A second cylinder is selected (S18). The fuel remaining in the high-pressure fuel distribution pipe 54 is injected into the second cylinder from the in-cylinder injector 44 using the fuel pressure (S22). The second threshold value is set with a fuel pressure lower than the first threshold value and a fuel pressure capable of injecting fuel into the cylinder stopped in the second half of the intake stroke or the first half of the compression stroke.

燃圧センサ５６の計測値が第２の閾値に達していなければ、吸気行程直前又は吸気行程前半の領域で停止した第３の気筒を選定し、第３の気筒の吸気通路に低圧燃料分配管４８から吸気通路インジェクタ４６を介して燃料を供給する（Ｓ２０）。
なお、別な制御方法として、高圧燃料分配管５４からの第２の気筒への燃料噴射と、低圧燃料分配管４８からの第３の気筒の吸気通路への燃料噴射とを併用してもよい。この場合、燃料噴射量の比率は低圧燃料分配管４８からの燃料噴射量を高圧燃料分配管５４からの燃料噴射量より多くする。例えば、低圧燃料分配管４８からの燃料噴射量と高圧燃料分配管５４からの燃料噴射量との比率を６：４又は７：３とする。 If the measured value of the fuel pressure sensor 56 has not reached the second threshold value, the third cylinder stopped immediately before the intake stroke or in the first half of the intake stroke is selected, and the low-pressure fuel distribution pipe 48 is connected to the intake passage of the third cylinder. Then, fuel is supplied via the intake passage injector 46 (S20).
As another control method, fuel injection from the high pressure fuel distribution pipe 54 to the second cylinder and fuel injection from the low pressure fuel distribution pipe 48 to the intake passage of the third cylinder may be used in combination. . In this case, the ratio of the fuel injection amount is such that the fuel injection amount from the low pressure fuel distribution pipe 48 is larger than the fuel injection amount from the high pressure fuel distribution pipe 54. For example, the ratio of the fuel injection amount from the low pressure fuel distribution pipe 48 to the fuel injection amount from the high pressure fuel distribution pipe 54 is set to 6: 4 or 7: 3.

次に、ＥＣＵ６０の指令を受けてスタータ３４が稼働し、クランク軸３２を回転させてクランキングを開始する(Ｓ２４)。クランキングの開始と連動して、また、ＥＣＵ６０の指令によってリレー６４がオンとなり、低圧燃料ポンプ４０に車載バッテリ５８の電力が供給され、低圧燃料ポンプ４０が稼働を開始する。クランキングの開始と同時に、クランク軸３２と連動してカム機構５２が作動し、カム機構５２と連動して吸気弁１８及び排気弁２０が作動すると共に、高圧燃料ポンプ５０が稼働を開始する(Ｓ２６)。
そして、前記工程とほとんど同時に、ＥＣＵ６０の指令で点火プラグ６６が作動し、Ｓ２２で気筒内に噴射された燃料が点火され、燃焼行程が開始される（Ｓ２８）。Ｓ２４からＳ２８までの工程は極めて短時間に行われる。 Next, in response to a command from the ECU 60, the starter 34 operates to rotate the crankshaft 32 and start cranking (S24). In conjunction with the start of cranking, the relay 64 is turned on by a command from the ECU 60, the electric power of the in-vehicle battery 58 is supplied to the low-pressure fuel pump 40, and the low-pressure fuel pump 40 starts operating. Simultaneously with the start of cranking, the cam mechanism 52 operates in conjunction with the crankshaft 32, the intake valve 18 and the exhaust valve 20 operate in conjunction with the cam mechanism 52, and the high-pressure fuel pump 50 starts operating ( S26).
Almost simultaneously with the above process, the spark plug 66 is actuated by a command from the ECU 60, the fuel injected into the cylinder is ignited in S22, and the combustion stroke is started (S28). The processes from S24 to S28 are performed in a very short time.

低圧燃料ポンプ４０及び高圧燃料ポンプ５０が作動した後は、ＥＣＵ６０の指令で、燃料タンク３８から供給される燃料が高圧燃料分配管５４から筒内インジェクタ４４を介して各気筒１２ａ〜１２ｄに噴射される。回転数センサ３７によって再始動後の燃焼サイクルの回数が計測され、設定された回数だけ、例えば２〜５回燃焼サイクルが行われる（Ｓ３０）。そして、吸気圧センサ２４の計測値が閾値まで低下したら（Ｓ３２）、ＥＣＵ６０によって、高圧燃料分配管５４からの燃料噴射を止め、低圧燃料分配管４８からの燃料噴射に切り換え（Ｓ３４）、その後、高圧燃料ポンプ５０の稼働を停止する（Ｓ３６）。
なお、高圧燃料分配管５４の稼働を続行させ、高圧燃料分配管５４からの燃料噴射と低圧燃料分配管４８からの燃料噴射とを併用してもよい。 After the low-pressure fuel pump 40 and the high-pressure fuel pump 50 are operated, the fuel supplied from the fuel tank 38 is injected from the high-pressure fuel distribution pipe 54 into the cylinders 12a to 12d via the in-cylinder injector 44 according to a command from the ECU 60. The The number of combustion cycles after restart is measured by the rotational speed sensor 37, and the combustion cycle is performed, for example, 2 to 5 times, for the set number of times (S30). When the measured value of the intake pressure sensor 24 decreases to the threshold value (S32), the ECU 60 stops the fuel injection from the high pressure fuel distribution pipe 54 and switches to the fuel injection from the low pressure fuel distribution pipe 48 (S34). The operation of the high-pressure fuel pump 50 is stopped (S36).
The operation of the high-pressure fuel distribution pipe 54 may be continued, and the fuel injection from the high-pressure fuel distribution pipe 54 and the fuel injection from the low-pressure fuel distribution pipe 48 may be used in combination.

図５は、再始動時に筒内インジェクタ４４から燃料を噴射する気筒の選定方法を具体的に示したものである。エンジン１０の再始動時、高圧燃料分配管５４の燃圧が第１の閾値以上であり、エンジン停止時の停止クランク角が領域Ａ及びＢにあるときは、圧縮行程であっても気筒内に燃料を供給可能であるので、圧縮行程で停止した気筒１２ｄに燃料を噴射し、停止クランク角が領域Ｃ及びＤにあるときは、気筒１２ｂに燃料を噴射する。   FIG. 5 specifically shows a method of selecting a cylinder that injects fuel from the in-cylinder injector 44 at the time of restart. When the engine 10 is restarted, when the fuel pressure in the high-pressure fuel distribution pipe 54 is equal to or greater than the first threshold value and the stop crank angle when the engine is stopped is in the regions A and B, fuel is injected into the cylinder even in the compression stroke. Therefore, when the stop crank angle is in the regions C and D, the fuel is injected into the cylinder 12b.

エンジン１０の再始動時、高圧燃料分配管５４の燃圧が第１の閾値に達せず、かつ第２の閾値以上であり、エンジン停止時の停止クランク角が領域Ａにあるときは、筒内圧が比較的低い圧縮行程前半領域で停止した気筒１２ｄに燃料噴射を行い、停止クランク角が領域Ｂ及びＣにあるときは、気筒１２ｂに燃料噴射を行い、停止クランク角が領域Ｄにあるときは、気筒１２ａに燃料噴射を行う。要は、高圧燃料分配管５４に残留した燃圧の燃圧に応じて供給可能な気筒を選定して供給する。   When the engine 10 is restarted, if the fuel pressure in the high-pressure fuel distribution pipe 54 does not reach the first threshold value and is equal to or greater than the second threshold value, and the stop crank angle when the engine is stopped is in the region A, the in-cylinder pressure is Fuel injection is performed on the cylinder 12d stopped in the first half region of the relatively low compression stroke. When the stop crank angle is in the regions B and C, fuel injection is performed on the cylinder 12b. When the stop crank angle is in the region D, Fuel is injected into the cylinder 12a. In short, a cylinder that can be supplied is selected and supplied in accordance with the fuel pressure remaining in the high-pressure fuel distribution pipe 54.

本実施形態によれば、アイドルストップ条件が解除され、エンジン１０を再始動させる時、筒内インジェクタ４４から高圧燃料分配管５４に残留している燃料を噴射し、気筒に供給される吸気量を抑えつつ、噴射される燃料の冷却作用で気筒内を冷却できるので、ノッキングの発生を防止できる。これによって、始動直後のドライバビリティやＮＶＨの悪化を防止できると共に、排ガス性状の悪化を防止できる。   According to this embodiment, when the idle stop condition is canceled and the engine 10 is restarted, the fuel remaining in the high-pressure fuel distribution pipe 54 is injected from the in-cylinder injector 44, and the intake air amount supplied to the cylinder is reduced. While suppressing, the inside of a cylinder can be cooled by the cooling effect | action of the injected fuel, Therefore Generation | occurrence | production of knocking can be prevented. As a result, it is possible to prevent deterioration of drivability and NVH immediately after start-up and deterioration of exhaust gas properties.

また、吸気通路インジェクタ４６からの燃料噴射でなく、筒内インジェクタ４４からの燃料噴射であるため、自動再始動時の燃料増量を低く抑えることができる。即ち、自動再始動時に吸気通路インジェクタ４６の噴射を用いる場合、吸気マニホールド１４の圧力が大気圧に近い状態になることで、吸気ポート等に付着する燃料が多くなる。
従って、自動再始動する際に吸気通路インジェクタ４６から噴射する場合は筒内に供給する燃料量を確保するため筒内インジェクタ４４からの噴射にくらべ多くの燃料量が必要になる。 In addition, since the fuel is injected from the in-cylinder injector 44 instead of the fuel injection from the intake passage injector 46, the fuel increase during the automatic restart can be kept low. That is, when the injection of the intake passage injector 46 is used at the time of automatic restart, the fuel adhering to the intake port or the like increases because the pressure of the intake manifold 14 becomes close to the atmospheric pressure.
Therefore, when the fuel is injected from the intake passage injector 46 at the time of automatic restart, a larger amount of fuel than the injection from the in-cylinder injector 44 is required to secure the amount of fuel supplied into the cylinder.

一方、筒内インジェクタ４４の噴射であれば、吸気ポート等に付着する燃料を考慮しなくて良い。そのため、吸気通路インジェクタ４６の噴射にくらべより少ない燃料量で自動再始動が可能であり、燃料消費（燃費）を抑えることができる。
さらに、本実施形態では、低圧燃料ポンプ４０及び高圧燃料ポンプ５０の稼働を待つことなく、選定された気筒に残留燃料を供給できるので、迅速な再始動が可能となる。また、この間低圧燃料ポンプ４０及び高圧燃料ポンプ５０が稼働されないので、ポンプ駆動フリクションを低減でき、これによって、始動時に必要な燃焼圧を低く抑えることで、燃焼に必要な燃料量を削減でき燃費を抑制できる。 On the other hand, in the case of injection from the in-cylinder injector 44, it is not necessary to consider the fuel adhering to the intake port or the like. Therefore, automatic restart can be performed with a fuel amount smaller than that of the injection of the intake passage injector 46, and fuel consumption (fuel consumption) can be suppressed.
Furthermore, in this embodiment, since the residual fuel can be supplied to the selected cylinder without waiting for the operation of the low-pressure fuel pump 40 and the high-pressure fuel pump 50, a quick restart is possible. In addition, since the low-pressure fuel pump 40 and the high-pressure fuel pump 50 are not operated during this time, the pump drive friction can be reduced, thereby reducing the amount of fuel required for combustion by keeping the combustion pressure required at the time of starting low. Can be suppressed.

また、エンジン１０の再始動時、高圧燃料分配管５４に残留した燃料の燃圧を計測し、その燃圧に応じて残留燃料を噴射可能な筒内圧を有する気筒を選定し、選定された気筒に残留燃料を噴射するようにしているので、燃圧が低いときでも気筒内への燃料噴射を確実に行うことができる。さらには、燃圧が高い場合、圧縮行程で停止した気筒に残留燃料を噴射することで、速やかに燃焼行程へ移行でき、迅速な再始動が可能となる。   Further, when the engine 10 is restarted, the fuel pressure of the fuel remaining in the high-pressure fuel distribution pipe 54 is measured, and a cylinder having an in-cylinder pressure capable of injecting the residual fuel is selected in accordance with the fuel pressure, and the remaining in the selected cylinder. Since the fuel is injected, the fuel can be reliably injected into the cylinder even when the fuel pressure is low. Furthermore, when the fuel pressure is high, by injecting residual fuel into the cylinder stopped in the compression stroke, it is possible to quickly shift to the combustion stroke and to quickly restart.

また、残留燃料を噴射する気筒を選定する際に、燃圧の閾値を２段階に設定し、燃圧に応じて木目細かく気筒を選定するようにしているので、気筒への燃料噴射を一層確実に行うことができる。さらに、第２の閾値に達しない燃圧の場合に、吸気行程直前又は吸気行程前半の領域で停止した気筒に低圧燃料供給管４２から燃料を噴射し、クランキングを開始した該気筒の吸引作用を利用して吸気通路に供給した燃料を該気筒内へ燃料を確実に注入できる。   In addition, when selecting a cylinder for injecting residual fuel, the fuel pressure threshold is set in two stages, and the cylinder is selected finely according to the fuel pressure, so that fuel injection into the cylinder is more reliably performed. be able to. Further, when the fuel pressure does not reach the second threshold, fuel is injected from the low-pressure fuel supply pipe 42 into the cylinder stopped in the region immediately before the intake stroke or in the first half of the intake stroke, and the suction action of the cylinder that has started cranking is performed. By using the fuel supplied to the intake passage by using the fuel, the fuel can be reliably injected into the cylinder.

また、第２の閾値に達しない燃圧の場合に、吸気通路への燃料噴射と共に、吸気行程後半又は圧縮行程前半の領域で停止した気筒への燃料直噴を併用し、少量の燃料を該気筒に噴射させることで、高圧燃料分配管５４に残留した燃料の燃圧が低い場合でも気筒内への燃料噴射が可能になる。このように、両燃料供給路から燃料を噴射させることで、燃料の着火を確実に行い、迅速な再始動が可能となる。
さらに、両燃料供給路から噴射される燃料噴射量の比率は、高圧燃料分配管５４からの燃料噴射量より低圧燃料供給管４２からの燃料噴射量を多くすることで、高圧燃料分配管５４からの燃料噴射量を少量にできる。これによって、高圧燃料分配管５４の燃圧が低くても、該気筒への燃料噴射を容易かつ確実に行うことができる。 When the fuel pressure does not reach the second threshold value, the fuel injection into the intake passage is used together with the direct fuel injection into the cylinder stopped in the second half of the intake stroke or the first half of the compression stroke, and a small amount of fuel is supplied to the cylinder. By injecting the fuel into the cylinder, the fuel can be injected into the cylinder even when the fuel pressure of the fuel remaining in the high-pressure fuel distribution pipe 54 is low. Thus, by injecting fuel from both fuel supply paths, the fuel can be reliably ignited and a quick restart is possible.
Further, the ratio of the fuel injection amount injected from both fuel supply paths is such that the fuel injection amount from the low-pressure fuel supply pipe 42 is larger than the fuel injection amount from the high-pressure fuel distribution pipe 54, thereby The amount of fuel injection can be reduced. Thus, even if the fuel pressure in the high-pressure fuel distribution pipe 54 is low, fuel injection into the cylinder can be performed easily and reliably.

また、回転数センサ３７で燃焼サイクルの回数を計測し、燃焼サイクルの回数が設定された回数に達し、かつ吸気圧センサ２４でサージタンク２２の圧力を計測し、吸気圧センサ２４の計測値が閾値以下となったときに、燃料噴射を高圧燃料分配管５４から低圧燃料供給管４２に切り替えるようにしているので、気筒内で圧縮圧力の増加に起因したノッキングの発生を防止可能な切替えタイミングを最適化できる。   Further, the number of combustion cycles is measured by the rotational speed sensor 37, the number of combustion cycles reaches the set number, and the pressure of the surge tank 22 is measured by the intake pressure sensor 24, and the measured value of the intake pressure sensor 24 is obtained. Since the fuel injection is switched from the high-pressure fuel distribution pipe 54 to the low-pressure fuel supply pipe 42 when the threshold value becomes lower than the threshold value, the switching timing capable of preventing the occurrence of knocking due to the increase of the compression pressure in the cylinder is set. Can be optimized.

本発明によれば、アイドルストップ後の迅速な再始動が可能になり、また、再始動時にノッキングの発生をなくすことで、始動直後のドライバビリティやＮＶＨの悪化や排ガス性状の悪化を防止できる。   According to the present invention, it is possible to quickly restart after an idle stop, and it is possible to prevent deterioration of drivability, NVH, and exhaust gas properties immediately after starting by eliminating the occurrence of knocking at the time of restart.

１０ ガソリン駆動エンジン
１２ａ、１２ｂ、１２ｃ、１２ｄ 気筒
１４ 吸気マニホールド
１６ 排気マニホールド
１８ 吸気弁
２０ 排気弁
２２ サージタンク
２４ 吸気圧センサ
２６ 吸気温センサ
２８ ピストン
３０ クランク室
３２ クランク軸
３４ スタータ
３６ クランク角センサ
３７ 回転数センサ
３８ 燃料タンク
４０ 低圧燃料ポンプ
４２ 低圧燃料供給管（第２燃料供給系統）
４４ 筒内インジェクタ
４６ 吸気通路インジェクタ
４８ 低圧燃料分配管（第２燃料供給系統）
５０ 高圧燃料ポンプ
５２ カム機構
５３ 高圧燃料供給管（第１燃料供給系統）
５４ 高圧燃料分配管（第１燃料供給系統）
５６ 燃圧センサ
５８ 車載バッテリ
６０ ＥＣＵ
６２ イグニッション・スィッチ
６４ リレー
６６ 点火プラグ
６８ アイドルストップ・スタート部（自動再始動手段）
７０ 燃料噴射制御部
ｃ 燃焼室 DESCRIPTION OF SYMBOLS 10 Gasoline drive engine 12a, 12b, 12c, 12d Cylinder 14 Intake manifold 16 Exhaust manifold 18 Intake valve 20 Exhaust valve 22 Surge tank 24 Intake pressure sensor 26 Intake temperature sensor 28 Piston 30 Crank chamber 32 Crankshaft 34 Starter 36 Crank angle sensor 37 Rotational speed sensor 38 Fuel tank 40 Low-pressure fuel pump 42 Low-pressure fuel supply pipe (second fuel supply system)
44 In-cylinder injector 46 Intake passage injector 48 Low-pressure fuel distribution pipe (second fuel supply system)
50 High-pressure fuel pump 52 Cam mechanism 53 High-pressure fuel supply pipe (first fuel supply system)
54 High-pressure fuel distribution pipe (first fuel supply system)
56 Fuel pressure sensor 58 On-board battery 60 ECU
62 Ignition switch 64 Relay 66 Spark plug 68 Idle stop / start section (automatic restart means)
70 Fuel Injection Control Unit c Combustion Chamber

Claims (4)

内燃機関の気筒内に燃料を噴射する第１燃料噴射手段と、
前記内燃機関の吸気通路に燃料を噴射する第２燃料噴射手段と、
前記内燃機関を自動で再始動する自動再始動手段を
を有する内燃機関の燃料噴射装置において、
前記第１燃料噴射手段の燃料圧力を計測する燃圧センサと、
前記燃圧センサの計測値に応じて前記第１燃料噴射手段に残留した燃料を噴射可能な筒内圧を有する気筒を選定し、該選定した気筒に前記第１燃料噴射手段に残留した燃料を噴射させる燃料噴射制御手段とを備えることを特徴とする内燃機関のの燃料噴射装置。 First fuel injection means for injecting fuel into a cylinder of the internal combustion engine;
Second fuel injection means for injecting fuel into the intake passage of the internal combustion engine;
In the fuel injection device for an internal combustion engine having automatic restart means for automatically restarting the internal combustion engine,
A fuel pressure sensor for measuring the fuel pressure of the first fuel injection means;
A cylinder having an in-cylinder pressure capable of injecting fuel remaining in the first fuel injection means is selected in accordance with a measured value of the fuel pressure sensor, and fuel remaining in the first fuel injection means is injected into the selected cylinder. A fuel injection device for an internal combustion engine, comprising: a fuel injection control means. 前記燃料噴射制御手段は、
スタータによるクランク軸の回転が開始される前に前記第１燃料噴射手段に残留した燃料を噴射させることを特徴とする内燃機関の燃料噴射装置。 The fuel injection control means includes
A fuel injection device for an internal combustion engine, wherein the fuel remaining in the first fuel injection means is injected before rotation of the crankshaft by the starter is started. 前記燃料噴射制御手段は、
前記第１燃料噴射手段の燃料圧力が第１の閾値以上であるとき、圧縮行程で停止した第１の気筒を選定し、
前記第１燃料噴射手段の燃料圧力が前記第１の閾値より低圧の第２の閾値以上であるとき、吸気行程又は圧縮行程前半の領域で停止した第２の気筒を選定し、
前記第１噴射手段の燃料圧力が前記第２の閾値未満のとき、吸気行程直前又は吸気行程前半の領域で停止した第３の気筒を選定することを特徴とする請求項１又は２に記載の内燃機関の燃料噴射装置。 The fuel injection control means includes
When the fuel pressure of the first fuel injection means is equal to or higher than a first threshold, the first cylinder stopped in the compression stroke is selected;
When the fuel pressure of the first fuel injection means is equal to or higher than the second threshold value lower than the first threshold value, the second cylinder stopped in the first half of the intake stroke or the compression stroke is selected;
3. The third cylinder stopped at a region immediately before the intake stroke or in the first half of the intake stroke when the fuel pressure of the first injection means is less than the second threshold value. A fuel injection device for an internal combustion engine. 前記燃料噴射制御手段は、前記第１燃料噴射手段の燃料圧力が前記第２の閾値未満のときは、少なくとも前記第２の燃料噴射手段からの噴射を行うことを特徴とする請求項３に記載の内燃機関の燃料噴射装置。
The fuel injection control means performs injection from at least the second fuel injection means when the fuel pressure of the first fuel injection means is less than the second threshold value. Fuel injection device for internal combustion engine.
JP2014061935A 2014-03-25 2014-03-25 Fuel injection device for internal combustion engine Active JP6395026B2 (en)

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JP2014061935A JP6395026B2 (en) 2014-03-25 2014-03-25 Fuel injection device for internal combustion engine
CN201580015219.1A CN106460686B (en) 2014-03-25 2015-03-23 Fuel injection device for internal combustion engine
EP15768804.5A EP3109443B1 (en) 2014-03-25 2015-03-23 Fuel injection device for internal combustion engine
PCT/JP2015/058783 WO2015146930A1 (en) 2014-03-25 2015-03-23 Fuel injection device for internal combustion engine
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