JP2006170165A - Fuel injection control device for cylinder direct injection type internal combustion engine - Google Patents

Fuel injection control device for cylinder direct injection type internal combustion engine Download PDF

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JP2006170165A
JP2006170165A JP2004367380A JP2004367380A JP2006170165A JP 2006170165 A JP2006170165 A JP 2006170165A JP 2004367380 A JP2004367380 A JP 2004367380A JP 2004367380 A JP2004367380 A JP 2004367380A JP 2006170165 A JP2006170165 A JP 2006170165A
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fuel injection
fuel
learning
injection
pulse width
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Shunichi Shiino
俊一 椎野
Kouya Hiratani
康冶 平谷
Akira Tayama
彰 田山
Taisuke Shiraishi
泰介 白石
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Nissan Motor Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a means capable of fuel injection control with a little learning error even under a stratified combustion operation condition of heavier load than conventional one in a cylinder direct injection type internal combustion engine. <P>SOLUTION: In a cylinder direct injection type spark ignition internal combustion engine including a mode executing a plurality times of fuel injection during one cycle under stratified combustion, and a learning means S4 regulating fuel injection pulse width while performing feed back control of a target sir fuel ratio according to air fuel ratio detection value and determining learning collection value by learning relation between fuel injection pulse width and fuel injection quantity based on regulation quantity of the fuel injection pulse width, different learning correction values independently learned are reflected to a plurality of times of fuel injection respectively (S4) in the mode executing a plurality of times of fuel injection during one stratified combustion cycle.(S2 while per, S3). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は筒内直接噴射式内燃機関の燃料噴射制御装置に関する。 The present invention relates to a fuel injection control device for a direct injection type internal combustion engine.

従来の筒内直接噴射式内燃機関として、低負荷運転条件で吸気行程噴射即ち均質燃焼モードにて略理論空燃比にフィードバック制御運転を行う際、燃料噴射を複数回に等分して分割噴射し、分割された噴射1回分の噴射パルス幅と燃料噴射量の対応関係を学習し、この学習補正値を燃費に優れる成層燃焼モードで運転される所定運転領域内における略同等のパルス幅と対応する燃料噴射量に反映させるようにしたものがある(特許文献1)。
上記のように、無負荷(アイドル)或いは低負荷領域で成層運転を行う場合、均質燃焼運転時と比べて必要な燃料噴射量は少なく、このような低負荷領域ではインジェクタの特性上、一般にパルス幅と燃料噴射量の線形性を保つことは難しい。そこで、前記パルス幅を学習補正することにより、アイドル或いは低負荷領域の成層燃焼モードにおいても所望の燃料噴射量を得ている。
特開平11−343911号
As a conventional direct injection internal combustion engine, when performing a feedback control operation to a substantially stoichiometric air-fuel ratio in an intake stroke injection, that is, in a homogeneous combustion mode under low load operating conditions, fuel injection is divided into multiple equal parts and divided injections The correspondence relationship between the injection pulse width for one divided injection and the fuel injection amount is learned, and this learning correction value corresponds to a substantially equivalent pulse width in a predetermined operation region operated in the stratified combustion mode excellent in fuel efficiency. There is one that is reflected in the fuel injection amount (Patent Document 1).
As described above, when the stratified operation is performed in the no-load (idle) or low-load region, the amount of fuel injection required is smaller than that in the homogeneous combustion operation. In such a low-load region, a pulse is generally used due to the characteristics of the injector. It is difficult to maintain the linearity of the width and the fuel injection amount. Therefore, by learning and correcting the pulse width, a desired fuel injection amount is obtained even in the stratified combustion mode in the idle or low load region.
JP-A-11-343911

一方、従来よりも高負荷な運転領域においても成層燃焼運転を行うときは、点火時期直前に点火プラグの近傍に微量の燃料を追加噴射している。このような運転領域においては、従来と比べて大きな成層混合気塊を形成する必要から、一般に従来よりも早期に燃料噴射を開始しており、この際、燃焼安定の観点から、先に噴射された燃料により形成される混合気塊の空燃比分布のばらつきの影響を受けることなく、点火時期に点火プラグ近傍が安定的に可燃混合比となっている必要があるためである。
前記追加噴射される燃料量は点火プラグ近傍を可燃混合比とするのに必要な量のみで足り、主噴射よりも大幅に少なく、一般にはアイドル成層燃焼時に必要な噴射量よりも少ない。
また、燃料噴射を1サイクル中に1回行い、追加噴射を行わない噴射(以下、1回噴射と記す)においては混合気塊形成の要求に応じて燃料圧力を設定することができるが、前記追加噴射時の燃料圧力は、通常は先に行われる主噴射とほぼ同等であり、主噴射による混合気塊形成の要求に応じて決定される。この燃料圧力は、一般的にアイドル成層燃焼時の燃料圧力と同等かそれよりも高い。
以上の燃料噴射量と燃料圧力との関係から、結果的に追加噴射のパルス幅は、アイドル成層燃焼時の燃料噴射パルス幅に比べて短いものとなる。
このため、上記背景技術を使用して前記高負荷運転領域におけるインジェクタ噴射特性の誤差を補正しようとすると、燃料噴射パルス幅が小さいため、アイドル吸気行程において燃料噴射を分割する回数を増やす必要があり、インジェクタ駆動制御が煩雑となる上、駆動間隔が狭まって燃料噴射量特性に影響を及ぼし、燃料噴射特性の学習誤差が生じやすくなるという問題点があった。
また、本技術を適用する比較的高負荷の運転条件と従来技術における学習領域であるアイドル均質燃焼モードかつ理論空燃比での運転条件では、燃料噴射を行う筒内圧力が大きく異なるため、インジェクタの燃料噴射特性も互いに相違し、燃料噴射特性の学習誤差が生じやすくなるという問題点があった。
On the other hand, when the stratified combustion operation is performed even in an operation region where the load is higher than the conventional one, a small amount of fuel is additionally injected in the vicinity of the spark plug immediately before the ignition timing. In such an operation region, since it is necessary to form a large stratified air-fuel mixture compared with the conventional case, fuel injection is generally started earlier than the conventional one. At this time, the fuel is injected first from the viewpoint of combustion stability. This is because the vicinity of the spark plug needs to have a stable combustible mixture ratio at the ignition timing without being affected by variations in the air-fuel ratio distribution of the air-fuel mixture formed by the fuel.
The amount of fuel to be additionally injected is only an amount necessary for making the vicinity of the spark plug a combustible mixture ratio, and is significantly smaller than the main injection, and generally smaller than the injection amount required at the time of idle stratified combustion.
In addition, in the injection in which fuel injection is performed once in one cycle and no additional injection is performed (hereinafter referred to as one injection), the fuel pressure can be set according to the request for the formation of the air-fuel mixture, The fuel pressure at the time of the additional injection is usually almost the same as the main injection performed first, and is determined according to the demand for the air-fuel mixture formation by the main injection. This fuel pressure is generally equal to or higher than the fuel pressure during idle stratified combustion.
From the relationship between the fuel injection amount and the fuel pressure, the pulse width of the additional injection is consequently shorter than the fuel injection pulse width during idle stratified combustion.
For this reason, if an attempt is made to correct the injector injection characteristic error in the high load operation region using the above background art, the fuel injection pulse width is small. Therefore, it is necessary to increase the number of times the fuel injection is divided in the idle intake stroke. In addition, the injector drive control is complicated, and the drive interval is narrowed, which affects the fuel injection amount characteristic, and a learning error of the fuel injection characteristic is likely to occur.
In addition, the in-cylinder pressure at which fuel injection is performed differs greatly between the relatively high load operating conditions to which the present technology is applied and the operating conditions in the idle homogeneous combustion mode and the stoichiometric air-fuel ratio, which are learning regions in the prior art. The fuel injection characteristics are also different from each other, and there is a problem that a learning error of the fuel injection characteristics is likely to occur.

本発明は、以上のような従来の問題点に鑑みてなされたものであり、筒内直接噴射式内燃機関において、従来よりも高負荷な成層燃焼運転条件においても、少ない学習誤差で燃料噴射制御ができる手段を提供することを目的とする。   The present invention has been made in view of the above-described conventional problems, and in a direct injection type internal combustion engine, fuel injection control is performed with less learning error even in stratified combustion operation conditions with a higher load than before. It is an object to provide a means capable of

このため本発明は、成層燃焼で1サイクル中に複数回の燃料噴射を行うモードを有し、空燃比検出値に応じて目標空燃比にフィードバック制御しつつ燃料噴射パルス幅を調整し、この燃料噴射パルス幅の調整量に基づいて燃料噴射パルス幅と燃料噴射量の関係を学習して学習補正値を求める学習手段を有する筒内直接噴射式火花点火内燃機関において、
前記成層燃焼1サイクル中に複数回燃料噴射を行うモードでは、複数回の燃料噴射に対し各々独立して学習された異なる学習補正値を反映させる構成とした。
For this reason, the present invention has a mode in which fuel injection is performed a plurality of times in one cycle in stratified combustion, and the fuel injection pulse width is adjusted while performing feedback control to the target air-fuel ratio in accordance with the air-fuel ratio detection value. In the in-cylinder direct injection spark ignition internal combustion engine having learning means for learning the relationship between the fuel injection pulse width and the fuel injection amount based on the adjustment amount of the injection pulse width and obtaining the learning correction value,
In the mode in which fuel injection is performed a plurality of times during one cycle of stratified combustion, different learning correction values learned independently are reflected on the plurality of fuel injections.

以上の構成により、実際に追加噴射を行う運転領域で追加噴射を実施し、その空燃比検出値に応じて直接追加噴射に対する学習補正値を求めることで、各噴射のパルス幅がそれぞれ異なる場合においても、各噴射に対して適した学習補正を行うことが可能となる。 With the above configuration, when the additional injection is performed in the operation region where the additional injection is actually performed, and the learning correction value for the direct additional injection is obtained according to the air-fuel ratio detection value, the pulse width of each injection is different. In addition, it is possible to perform learning correction suitable for each injection.

以下に、本発明の第一実施形態について説明する。
図1に、本実施形態の構成概略を示す。エンジン1へ取り込まれる吸気は、エアクリーナ2、エアフローメータ3、スロットルバルブ4を経てコレクタ5に入り、各気筒の吸気通路6へと導かれる。前記エアフローメータ3は吸気流量を計測し、スロットルバルブ4は吸気流量を調節する。吸気通路6の下流にはシリンダ8が接続されており、吸気弁7が開かれると該シリンダ8内へ吸気が導入される。
シリンダ8の燃焼室上部には、インジェクタ9が燃料噴孔を臨ませて配設されており、エアフローメータ3で計測された空気流量をもとに算出された量の燃料が、該インジェクタ9から噴射される。混合気となった燃料は、シリンダ8内を往復運動するピストン10にて圧縮され、燃焼室上部にその電極を臨ませて配設された点火プラグ11によって着火され燃焼する。燃焼後の排気は、排気バルブ12を開いて排気通路13を通って排出される。排気通路13には空燃比センサ14が設けられており、該空燃比センサ14によって排気の空燃比が検出される。
図2に本実施形態における空燃比センサ14の配置を示す。図2に示すように、本実施形態においては各気筒の排気通路13に空燃比センサ14が取り付けられ、各気筒の空燃比を検出し、各気筒で別々に学習を行っている。気筒毎に学習補正値を持つため、気筒毎に独立したフィードバック系により各気筒が個別に学習補正を行うことが可能となり、インジェクタ個体特性のばらつき等に起因する各気筒の燃料噴射量差を個別に補正することができる。
尚、図示しないアクセル開度、冷却水温度などの入力に基づくスロットル開度制御、図示しないエンジン回転入力及び吸気流量などに基づく燃料噴射量、噴射時期及び点火時期の計算、並びに空燃比に基づく学習補正値の算出は、エンジンコントロールユニット15によって行われる。
以下に、本実施形態における燃料噴射学習制御について説明する。
図3及び図4に、本実施形態における燃料噴射学習制御のフローチャートを示す。
まずステップ(以下S)1において、基本パルス幅TIを計算する。S1については別途図5を用いて詳述する。
S2では、追加パルス幅TI2を参照する。TI2は成層燃焼モードかつ比較的高負荷運転を行う際、安定した着火を行う目的で燃料を追加噴射するための微小パルス幅で、均質燃焼モード及び成層燃焼モードかつ中低負荷では通常TI2=0となる。TI2は例えばエンジン回転速度Ne及び目標トルクTTCに割り付けたマップを予めECUのROMに格納しておき、これを参照することで求めることができる。
S3では主パルス幅TI1を求める。TI1は基本パルス幅TIと追加パルス幅TI2の差であり、追加噴射を行わない場合、即ちTI2=0の場合はTI1=TIとなる。
S4では、各気筒の学習補正値LRTI1n、LRTI2nを求める。ここでLRTI1nは主パルス幅TI1に対応する学習補正値、LRTI2nは追加パルス幅TI2に対応する学習補正値であり、添字のnは気筒番号(n=1〜気筒数)である。このように、成層燃焼1サイクル中において複数回の燃料噴射(ここでは主噴射と追加噴射の2回)に対し異なる学習補正値を反映させるため、各噴射のパルス幅が互いに異なる場合においても、それぞれに適した学習補正を行うことが可能となる。
複数回の噴射における噴射量誤差は、最もパルス幅の短い燃料噴射(ここでは追加噴射)の誤差が支配的である。図6にパルス幅と燃料噴射量の関係の例を示す。図6に示すように、比較的長いパルス幅の領域では比例関係にあるが、短いパルス幅の領域では開弁期間に占める弁開閉動作中の期間の割合が大きくなることなどに起因して、上記比例関係に対する誤差が大きくなることがわかる。このため、複数回の噴射のうち最も短いパルス幅の燃料噴射(ここでは追加噴射)にも当該運転状態で求めた学習補正値を反映させ、上記誤差を補正している。
前記学習補正値LRTI1n、LRTI2nは、パルス幅に応じて異なる値をとり得る。即ちパルス幅TI1とTI2が異なる時は、学習補正値LRTI1n、LRTI2nも異なったものとなり得る。燃料噴射パルス幅に応じて異なる学習補正値を持つ構成としたため、パルス幅毎に異なる噴射量誤差に対応して学習補正を行うことが可能となる。
また学習補正値LRTI1n、LRTI2nは、燃料圧力に応じても異なる値をとり得る。一般に短いパルス幅の領域におけるインジェクタの噴射量誤差は、燃料圧力に応じて異なるが、本構成によりこれに対応して学習補正を行うことが可能となる。
さらに、前述気筒番号の導入とも関連して、本実施形態においては気筒毎に独立して学習が行われるため、学習補正値も気筒毎に異なる値をとり得る。例えばECUのRAMに燃料圧力Pfとパルス幅TI1, TI2に割り付けたマップを気筒数分設け、各気筒に対応したマップの各格子に学習補正値を格納し、ここから学習補正値LRTI1n、LRTI2nを参照することができる。各気筒毎に学習補正値を持つため、インジェクタ個体特性のばらつき等に起因する各気筒の燃料噴射量差を、個別に補正することができる。
S5では、参照する学習マップの格子が前回の学習実行時から変化したか否かを判定する。学習は空燃比フィードバック制御の結果をもとに行うため、フィードバックが安定するための時間を要する。したがって、本実施形態では、同一学習領域において連続運転している場合にのみ学習を継続させるために本ステップが設けられている。
S5の判定がYesの場合は、S6〜S8に進み、学習カウンタCLR、空燃比フィードバック係数の総和SA1n、SA2n、気筒別空燃比フィードバック係数A1n、A2nをリセットし、S10に進む。
一方、S5の判定がNoの場合は、S9に進み学習カウンタCLRをインクリメントしたうえでS10に進む。
S10では、各気筒別の燃料噴射パルス幅CTI1n、CTI2nを算出する。CTI1n、CTI2nはそれぞれ、パルス幅TI1、TI2各々に気筒別空燃比フィードバック係数A1n、A2n各々と学習補正値LRTI1n、LRTI2n各々の和を乗じ、さらに無効パルス幅Tsを加えたものである。ここで無効パルス幅Tsは、インジェクタ燃料噴孔が開閉駆動するための、燃料が噴射されない無駄時間を意味し、電源電圧などに応じて求めることができる。例えば、予め実験等により求めた値をECUのROMに格納しておき、電源電圧に応じて参照することで、無効パルス幅Tsを求めることが可能である。
S11では、燃料噴射時期及び点火時期を算出し、S10の結果と併せて、各気筒に所望のタイミングで所望量の燃料を噴射し、所望のタイミングにて混合気に点火し燃焼させる。尚、S11については別途図7を用いて詳述する。
S12では、各気筒の空燃比センサ14によって、気筒別空燃比LMDnを検出する。
S13では、追加噴射モード運転中か否かを、TI2>0であるか否かで判定する。S13の判定がYesの場合、即ち追加噴射モード運転中の場合は、S14〜21及びS23において追加噴射に対する学習を行い、S13の判定がNoの場合、即ち1サイクル中に1回噴射モード運転中の場合は、S24〜32において主噴射に対する学習を行う。
この際、1回噴射モードにて学習した後、成層燃焼1サイクル中に複数回燃料噴射を行うモードにおける学習を行うことにより、複数回噴射燃料噴射を行う時の噴射量誤差はパルス幅の最も短い燃料噴射(ここでは追加噴射)の誤差のみとなり、学習補正の精度を向上させることができる。
S14では、空燃比センサ14において検出した気筒別空燃比LMDnと目標当量比TFBYAを比較して、気筒別空燃比フィードバック係数A2nの値を更新する。A2n=1であれば無補正であり、目標に対して検出した空燃比がリーンであれば増加させ、リッチであれば減少させることで、各気筒別の追加噴射パルス幅CTI2nを増減補正させる。
S15では、後に気筒別空燃比フィードバック係数A2nの補正分の平均値を求めるための空燃比フィードバック係数の総和SA2nに気筒別空燃比フィードバック係数A2nを加える。
S16では、学習カウンタCLRが所定値Tに達したか否かを判定する。ここでTはフィードバックの安定に要するループ回数を意味し、S16の判定がYesの場合はS17〜23に進み学習補正値の更新を行う。
S17では、空燃比フィードバック係数の総和SA2nからT[T×フィードバック係数基準値(=1)=T]を減じたものをTで除算することで、気筒別空燃比フィードバック係数A2nの補正分の平均値を算出し、これに学習補正値LRTI2nを加えたものを新学習補正値NLRTI2nとする。
S18では、NLRTI2nを学習マップの所定の格子に格納し、学習マップを更新する。
S19では、学習カウンタCLR、空燃比フィードバック係数の総和SA2n、気筒別空燃比フィードバック係数A2nをリセットする。
S20では、学習補正値の収束判定を行う。即ち、前回学習補正値NLRTI2nと今回学習補正値LRTI2nとの差が所定値LRTS以内であれば、学習補正値が収束したと判定してS21に進み、収束判定フラグFLRTInに1を代入し、所定値LRTSを超えているときは収束していないと判定してS23に進み、収束判定フラグFLRTInに0を代入する。
最後にS22において、各気筒に設けられた領域学習収束マップに、当該領域の収束判定フラグを格納する。
なお、1回噴射の場合に行われる主噴射学習に関するルーチンS24〜32は、追加噴射学習と全く同様に行われ、S14〜21及びS23の各変数の添字2を1に読み替えたものであるので説明を省略する。
Below, 1st embodiment of this invention is described.
FIG. 1 shows a schematic configuration of the present embodiment. The intake air taken into the engine 1 enters the collector 5 through the air cleaner 2, the air flow meter 3, and the throttle valve 4, and is guided to the intake passage 6 of each cylinder. The air flow meter 3 measures the intake flow rate, and the throttle valve 4 adjusts the intake flow rate. A cylinder 8 is connected downstream of the intake passage 6, and intake air is introduced into the cylinder 8 when the intake valve 7 is opened.
An injector 9 is disposed above the combustion chamber of the cylinder 8 so as to face the fuel injection hole, and an amount of fuel calculated based on the air flow rate measured by the air flow meter 3 is supplied from the injector 9. Be injected. The fuel that has become the air-fuel mixture is compressed by a piston 10 that reciprocates in the cylinder 8, and is ignited and burned by a spark plug 11 that is disposed with its electrode facing the upper portion of the combustion chamber. The exhaust after combustion is discharged through the exhaust passage 13 by opening the exhaust valve 12. An air-fuel ratio sensor 14 is provided in the exhaust passage 13, and the air-fuel ratio of the exhaust is detected by the air-fuel ratio sensor 14.
FIG. 2 shows the arrangement of the air-fuel ratio sensor 14 in the present embodiment. As shown in FIG. 2, in this embodiment, an air-fuel ratio sensor 14 is attached to the exhaust passage 13 of each cylinder, detects the air-fuel ratio of each cylinder, and learns separately for each cylinder. Since each cylinder has a learning correction value, it becomes possible for each cylinder to individually perform learning correction by an independent feedback system for each cylinder, and individual differences in fuel injection amount due to variations in individual injector characteristics, etc. Can be corrected.
In addition, throttle opening control based on inputs such as accelerator opening and cooling water temperature (not shown), fuel injection amount based on engine rotation input and intake air flow (not shown), calculation of injection timing and ignition timing, and learning based on air-fuel ratio The correction value is calculated by the engine control unit 15.
Hereinafter, the fuel injection learning control in the present embodiment will be described.
3 and 4 show a flowchart of the fuel injection learning control in the present embodiment.
First, in step (hereinafter S) 1, a basic pulse width TI is calculated. S1 will be described in detail with reference to FIG.
In S2, the additional pulse width TI2 is referred to. TI2 is a small pulse width for additionally injecting fuel for the purpose of stable ignition when performing a stratified combustion mode and a relatively high load operation, and is usually TI2 = 0 in a homogeneous combustion mode, a stratified combustion mode and medium to low load It becomes. The TI2 can be obtained by, for example, storing a map assigned to the engine speed Ne and the target torque TTC in advance in the ROM of the ECU and referring to this.
In S3, the main pulse width TI1 is obtained. TI1 is a difference between the basic pulse width TI and the additional pulse width TI2. When no additional injection is performed, that is, when TI2 = 0, TI1 = TI.
In S4, learning correction values LRTI1n and LRTI2n for each cylinder are obtained. Here, LRTI1n is a learning correction value corresponding to the main pulse width TI1, LRTI2n is a learning correction value corresponding to the additional pulse width TI2, and the subscript n is a cylinder number (n = 1 to the number of cylinders). Thus, in order to reflect different learning correction values for a plurality of fuel injections (in this case, two times of main injection and additional injection) in one stratified combustion cycle, even when the pulse widths of the respective injections are different from each other, It is possible to perform learning correction suitable for each.
The error in fuel injection (here, additional injection) with the shortest pulse width is dominant in the injection amount error in the multiple injections. FIG. 6 shows an example of the relationship between the pulse width and the fuel injection amount. As shown in FIG. 6, there is a proportional relationship in a relatively long pulse width region, but in a short pulse width region, the ratio of the period during the valve opening / closing operation occupies the valve opening period increases. It turns out that the error with respect to the said proportionality relationship becomes large. For this reason, the learning correction value obtained in the operation state is also reflected in the fuel injection (here, additional injection) having the shortest pulse width among the plurality of injections, and the error is corrected.
The learning correction values LRTI1n and LRTI2n can take different values depending on the pulse width. That is, when the pulse widths TI1 and TI2 are different, the learning correction values LRTI1n and LRTI2n can be different. Since the learning correction value varies depending on the fuel injection pulse width, it is possible to perform learning correction corresponding to the injection amount error that differs for each pulse width.
Further, the learning correction values LRTI1n and LRTI2n can take different values depending on the fuel pressure. In general, the injection amount error of the injector in the region of a short pulse width varies depending on the fuel pressure, but according to this configuration, it is possible to perform learning correction correspondingly.
Further, in connection with the introduction of the aforementioned cylinder number, in this embodiment, learning is performed independently for each cylinder, so that the learning correction value can also take a different value for each cylinder. For example, maps of fuel pressure Pf and pulse widths TI1 and TI2 are provided for the number of cylinders in the RAM of the ECU, and learning correction values are stored in each grid of the map corresponding to each cylinder, from which learning correction values LRTI1n and LRTI2n are stored. You can refer to it. Since each cylinder has a learning correction value, it is possible to individually correct the fuel injection amount difference of each cylinder caused by variations in individual injector characteristics.
In S5, it is determined whether or not the grid of the learning map to be referenced has changed since the previous learning execution. Since learning is performed based on the result of the air-fuel ratio feedback control, it takes time for the feedback to stabilize. Therefore, in this embodiment, this step is provided in order to continue learning only when continuous operation is performed in the same learning region.
If the determination in S5 is Yes, the process proceeds to S6 to S8, the learning counter CLR, the sum of the air-fuel ratio feedback coefficients SA1n, SA2n, the cylinder-specific air-fuel ratio feedback coefficients A1n, A2n are reset, and the process proceeds to S10.
On the other hand, if the determination in S5 is No, the process proceeds to S9, the learning counter CLR is incremented, and then the process proceeds to S10.
In S10, fuel injection pulse widths CTI1n and CTI2n for each cylinder are calculated. CTI1n and CTI2n are obtained by multiplying each of the pulse widths TI1 and TI2 by the sum of the cylinder-by-cylinder air-fuel ratio feedback coefficients A1n and A2n and the learning correction values LRTI1n and LRTI2n, respectively, and further adding an invalid pulse width Ts. Here, the invalid pulse width Ts means a dead time in which fuel is not injected for the injector fuel injection hole to be opened and closed, and can be obtained according to a power supply voltage or the like. For example, it is possible to obtain the invalid pulse width Ts by storing a value obtained by an experiment or the like in advance in the ROM of the ECU and referring to it according to the power supply voltage.
In S11, the fuel injection timing and ignition timing are calculated, and together with the result of S10, a desired amount of fuel is injected into each cylinder at a desired timing, and the air-fuel mixture is ignited and burned at the desired timing. S11 will be described in detail with reference to FIG.
In S12, the cylinder air-fuel ratio LMDn is detected by the air-fuel ratio sensor 14 of each cylinder.
In S13, it is determined whether or not the additional injection mode operation is being performed based on whether or not TI2> 0. When the determination of S13 is Yes, that is, when the additional injection mode operation is being performed, learning for the additional injection is performed in S14 to 21 and S23, and when the determination of S13 is No, that is, the single injection mode operation is performed during one cycle. In this case, learning for the main injection is performed in S24 to S32.
At this time, after learning in the single injection mode, by performing learning in the mode in which multiple fuel injections are performed during one cycle of stratified combustion, the injection amount error when performing multiple fuel injections is the largest in the pulse width. Only an error of short fuel injection (here, additional injection) is provided, and the accuracy of learning correction can be improved.
In S14, the cylinder-by-cylinder air-fuel ratio LMDn detected by the air-fuel ratio sensor 14 is compared with the target equivalent ratio TFBYA, and the value of the cylinder-by-cylinder air-fuel ratio feedback coefficient A2n is updated. If A2n = 1, no correction is performed, and if the air-fuel ratio detected with respect to the target is lean, it is increased, and if it is rich, the additional injection pulse width CTI2n for each cylinder is increased or decreased.
In S15, the cylinder-by-cylinder air-fuel ratio feedback coefficient A2n is added to the sum SA2n of the air-fuel ratio feedback coefficients for later obtaining an average value for correction of the cylinder-by-cylinder air-fuel ratio feedback coefficient A2n.
In S16, it is determined whether or not the learning counter CLR has reached a predetermined value T. Here, T means the number of loops required for stabilizing the feedback. If the determination in S16 is Yes, the process proceeds to S17 to 23 and the learning correction value is updated.
In S17, by subtracting T [T × feedback coefficient reference value (= 1) = T] from the sum SA2n of the air-fuel ratio feedback coefficients, and dividing by T, the average of the corrected air-fuel ratio feedback coefficient A2n for each cylinder is corrected. A value obtained by adding a learning correction value LRTI2n to this value is set as a new learning correction value NLRTI2n.
In S18, NLRTI2n is stored in a predetermined lattice of the learning map, and the learning map is updated.
In S19, the learning counter CLR, the sum SA2n of the air-fuel ratio feedback coefficients, and the cylinder-by-cylinder air-fuel ratio feedback coefficient A2n are reset.
In S20, the convergence correction of the learning correction value is performed. That is, if the difference between the previous learning correction value NLRTI2n and the current learning correction value LRTI2n is within the predetermined value LRTS, it is determined that the learning correction value has converged, the process proceeds to S21, and 1 is assigned to the convergence determination flag FLRTIn. If the value exceeds the value LRTS, it is determined that it has not converged, and the process proceeds to S23 where 0 is substituted for the convergence determination flag FLRTIn.
Finally, in S22, the convergence determination flag for the region is stored in the region learning convergence map provided for each cylinder.
The routines S24 to S32 related to the main injection learning performed in the case of the single injection are performed in the same manner as the additional injection learning, and the subscript 2 of each variable of S14 to 21 and S23 is replaced with 1. Description is omitted.

前述図3におけるS1について、その詳細フローチャートの一例を図5に示す。
まずS1−1において、エンジン回転速度Ne、冷却水温Tw、アクセル開度Apsを読み込み、S1−2でアクセル開度Apsから目標トルクTTCを求める。目標トルクTTCは例えば予めアクセル開度Apsに割り付けたテーブルをECUのROMに格納しておき、アクセル開度Apsの値に応じて参照することで求めることができる。
An example of a detailed flowchart of S1 in FIG. 3 is shown in FIG.
First, in S1-1, the engine speed Ne, the coolant temperature Tw, and the accelerator opening Aps are read, and in S1-2, the target torque TTC is obtained from the accelerator opening Aps. The target torque TTC can be obtained, for example, by storing a table previously assigned to the accelerator opening Aps in the ROM of the ECU and referring to it according to the value of the accelerator opening Aps.

S1−3では、水温Twが所定値LTw以上であるか否かを判定する。S1−3の判定がNoの場合は機関温度が低いため、希薄燃焼モードでは燃焼が安定せず運転性低下の可能性があると判断し、S1−7に進み、目標当量比TFBYAを読み込む。尚、ここで読み込まれる目標当量比TFBYAマップの下限は1(理論空燃費)に設定されているため、希薄燃焼は行われない。   In S1-3, it is determined whether or not the water temperature Tw is equal to or higher than a predetermined value LTw. If the determination in S1-3 is No, the engine temperature is low, so it is determined that combustion is not stable in the lean combustion mode and there is a possibility that the drivability may decrease, and the process proceeds to S1-7 to read the target equivalent ratio TFBYA. Since the lower limit of the target equivalent ratio TFBYA map read here is set to 1 (theoretical air fuel consumption), lean combustion is not performed.

一方、S1−3の判定がYesの場合は、S1−4に進み、主噴射の学習が収束しているか否かについて領域学習収束マップを参照して判定し、Yesの場合はS1−5に、Noの場合はS1−6に進む。
ここでS1−5、S1−6は何れも目標当量比TFBYAを読み込むステップであるが、S1−6は主噴射の学習が収束していない状態であるため、追加噴射の学習を精度良く行うことができない可能性があり、本来成層燃焼モードかつ追加噴射を用いて運転する領域の目標当量比TFBYAを1としてストイキ運転を行い、この領域での成層運転を禁止している。なお、図示しないが、S1−6或いはS1−7を通ったときは、図3のS2においては常に追加パルス幅TI2=0として、追加噴射を禁止する。このようにS1−4、S1−6を設けることにより、1回噴射の学習が収束し、精度良く主噴射を行うことが可能になった後に、追加噴射を用いた運転を許可し、高精度の追加噴射の学習を行っている。
すなわち、図6に示したように、複数回噴射のうち最も短いパルス幅の燃料噴射を除く燃料噴射(ここでは主噴射)で用いるパルス幅の領域は、1回噴射のパルス幅領域に含まれている。したがって、複数回の噴射のうち最も短いパルス幅の燃料噴射を除く噴射パルス幅には、1回噴射モードにおいて求めた学習補正値を主噴射学習補正値として反映させることができる。
On the other hand, if the determination in S1-3 is Yes, the process proceeds to S1-4, and it is determined with reference to the region learning convergence map as to whether or not the learning of the main injection has converged. In the case of Yes, the process proceeds to S1-5. If No, the process proceeds to S1-6.
Here, both S1-5 and S1-6 are steps for reading the target equivalent ratio TFBYA, but since S1-6 is a state in which learning of the main injection has not converged, learning of additional injection should be performed with high accuracy. Therefore, stoichiometric operation is performed with the target equivalent ratio TFBYA of the region that is originally operated using the stratified combustion mode and the additional injection being set to 1, and the stratified operation in this region is prohibited. Although not shown, when S1-6 or S1-7 is passed, the additional pulse width TI2 = 0 is always set in S2 of FIG. 3 to prohibit additional injection. By providing S1-4 and S1-6 in this manner, after learning of one injection has converged and it becomes possible to perform main injection with high accuracy, operation using additional injection is permitted, and high accuracy is achieved. Learning about additional injections.
That is, as shown in FIG. 6, the pulse width region used for fuel injection (here, main injection) excluding the shortest pulse width fuel injection among the multiple injections is included in the single injection pulse width region. ing. Accordingly, the learning correction value obtained in the single injection mode can be reflected as the main injection learning correction value in the injection pulse width excluding the fuel injection having the shortest pulse width among the plurality of injections.

これに対し、パルス幅と燃料噴射量の比例関係(図6参照)の誤差が主噴射で用いるパルス幅領域であまり大きくない場合は、主噴射の学習が収束していなくても、追加噴射の学習精度にあまり影響しない場合もある。このような場合は、本ステップを省略することによって演算負荷を軽減し、学習速度を向上させるという方法も可能である。
S1−8では、目標当量比TFBYAと目標トルクTTCから必要な吸入空気量を算出し、これをもとに目標スロットル開度TgTV0を計算する。この結果に基づき、スロットル開度が調節される。
On the other hand, if the error in the proportional relationship between the pulse width and the fuel injection amount (see FIG. 6) is not so large in the pulse width region used in the main injection, even if the learning of the main injection has not converged, the additional injection In some cases, learning accuracy is not significantly affected. In such a case, it is possible to reduce the calculation load by omitting this step and improve the learning speed.
In S1-8, the required intake air amount is calculated from the target equivalent ratio TFBYA and the target torque TTC, and the target throttle opening degree TgTV0 is calculated based on this. Based on this result, the throttle opening is adjusted.

S1−9では、エアフローメータ3の出力より吸入空気量Qaを読み込む。
S1−10では、目標燃料圧力Pfを算出し、この結果に基づき、図示しない燃料ポンプによってインジェクタ9に燃料が圧送される。
S1−11では、燃料圧力補正値kPfが算出される。kPfは異なる燃料圧力においても同質量の燃料を噴射するためのパルス幅補正係数に単位換算用の定数を乗じたものである。
In S1-9, the intake air amount Qa is read from the output of the air flow meter 3.
In S1-10, the target fuel pressure Pf is calculated, and based on this result, the fuel is pumped to the injector 9 by a fuel pump (not shown).
In S1-11, a fuel pressure correction value kPf is calculated. kPf is obtained by multiplying a pulse width correction coefficient for injecting fuel of the same mass even at different fuel pressures by a constant for unit conversion.

最後にS1−12において、目標当量比TFBYAと燃料圧力補正値kPfの積に1気筒1サイクルあたりの吸入空気量[Qa/(Ne・n/2):nは気筒数]を乗じることで、基本パルス幅TIが求められる。
次に、前述図4におけるS11について、その詳細フローチャートの一例を図7に示す。
Finally, in S1-12, the product of the target equivalent ratio TFBYA and the fuel pressure correction value kPf is multiplied by the intake air amount [Qa / (Ne · n / 2): n is the number of cylinders] per cycle. A basic pulse width TI is determined.
Next, FIG. 7 shows an example of a detailed flowchart of S11 in FIG.

まずS11−1において、追加噴射モード運転中か否かを、追加パルス幅TI2>0であるか否かで判定する。
S11−1の判定がYes(追加噴射モード)の場合は、S11−2に進み、追加噴射モード用の点火時期ADVを読み込み、S11−3において主噴射時期IT1、S11−4において追加噴射時期IT2を読み込む。これらの値は、例えば基本パルス幅TIとエンジン回転速度Neとをパラメータとして割り付けたマップにデータを格納しておき、TI、Neに応じて参照することで求めることができる。
First, in S11-1, it is determined whether or not the additional injection mode operation is being performed based on whether or not the additional pulse width TI2> 0.
If the determination in S11-1 is Yes (additional injection mode), the process proceeds to S11-2, where the ignition timing ADV for the additional injection mode is read, the main injection timing IT1 in S11-3, and the additional injection timing IT2 in S11-4. Is read. These values can be obtained, for example, by storing data in a map in which the basic pulse width TI and the engine rotational speed Ne are assigned as parameters and referring to them according to TI and Ne.

S11−5では、追加噴射の学習補正値LRTI2nによるパルス幅変化量DTM2nを、追加パルス幅TI2とLRTI2nの積により求める。尚、パルス幅は空燃比フィードバック係数A2nによっても変化するため、計算の際にこれを考慮し、DTM2n=TI2×(A2n−1+LRTI2n)とする方法も可能である。
S11−6では、追加噴射時期IT2からパルス幅変化量DTM2nのクランク角度換算値を減じ、追加噴射開始時期を補正する。微量の燃料を追加噴射しこれに点火する場合、安定した着火性能を得るためには、追加噴射によって点火時に点火位置が可燃混合比となるように混合気塊を形成しなくてはならない。そのためには噴射時期と点火時期の関係が重要であるが、学習補正を行うと噴射パルス幅が変化するため、点火時期に形成される混合気塊の状態が変化する。そこで、学習補正値に応じて複数回の噴射のうち最もパルス幅の短い燃料噴射(ここでは追加噴射)の開始時期を調節することによって、学習補正値を反映しても点火時期に形成される混合気塊の状態を可燃混合比に保ち、安定した着火性能を得ることが可能となる。
また、上記燃料噴射の開始時期を調節する際、学習補正値を反映しても該噴射終了時期が学習補正を行う前と略同等となるように調節するようにしたため、噴射終了から点火までの時間が学習補正値によらず略一定となり、噴射終了時に噴射された燃料により形成される混合気塊の点火時の位置を一定に保つことができ、安定した着火を得ることができる。この方法は、例えば追加噴射によって形成される混合気の終端に点火するような場合に有効である。その他、例えば混合気の中央に点火するような内燃機関において、噴射期間の中心と点火時期との関係が変化しないようにする方法が有効である場合は、この関係を一定に保つような補正を行う構成とすればよい。
In S11-5, the pulse width change amount DTM2n based on the additional injection learning correction value LRTI2n is obtained by the product of the additional pulse width TI2 and LRTI2n. Note that since the pulse width also changes depending on the air-fuel ratio feedback coefficient A2n, a method of taking this into consideration in the calculation is DTM2n = TI2 × (A2n−1 + LRTI2n).
In S11-6, the crank angle conversion value of the pulse width change amount DTM2n is subtracted from the additional injection timing IT2 to correct the additional injection start timing. When a small amount of fuel is additionally injected and ignited, in order to obtain stable ignition performance, an air-fuel mixture must be formed so that the ignition position becomes a combustible mixture ratio at the time of ignition by additional injection. For this purpose, the relationship between the injection timing and the ignition timing is important. However, since the injection pulse width changes when learning correction is performed, the state of the air-fuel mixture formed at the ignition timing changes. Therefore, by adjusting the start timing of the fuel injection having the shortest pulse width (in this case, additional injection) of the plurality of injections according to the learning correction value, the ignition timing is formed even if the learning correction value is reflected. It is possible to maintain the state of the air-fuel mixture at a combustible mixing ratio and obtain stable ignition performance.
In addition, when adjusting the fuel injection start timing, even if the learning correction value is reflected, the injection end timing is adjusted to be substantially the same as before the learning correction is performed. The time is substantially constant regardless of the learning correction value, and the position at the time of ignition of the air-fuel mixture formed by the fuel injected at the end of injection can be kept constant, so that stable ignition can be obtained. This method is effective when, for example, the end of the air-fuel mixture formed by additional injection is ignited. In addition, for example, in an internal combustion engine that ignites in the center of the air-fuel mixture, if a method that prevents the relationship between the center of the injection period and the ignition timing from changing is effective, a correction that keeps this relationship constant is performed. What is necessary is just to make it the structure to perform.

一方、S11−1の判定がNo(1回噴射モード)の場合は、S11−7に進み、1回噴射の点火時期ADVを読み込み、次のS11−8で主噴射時期IT1を読み込む。
また、ECUのハードウェア上の制約から、燃料噴射時期を各気筒別に制御できない場合は、パルス幅変化量DTM2nの平均値を用いて補正する方法も可能である。この場合であっても前述と同様の安定した着火性能および燃焼安定性向上の効果は、ある程度得られるものと思われる。
On the other hand, if the determination in S11-1 is No (single injection mode), the process proceeds to S11-7, and the ignition timing ADV of the single injection is read, and the main injection timing IT1 is read in the next S11-8.
Further, when the fuel injection timing cannot be controlled for each cylinder due to restrictions on the hardware of the ECU, a correction method using an average value of the pulse width change amount DTM2n is also possible. Even in this case, it is considered that the same stable ignition performance and combustion stability improvement effect as described above can be obtained to some extent.

一方、追加噴射時の噴射量誤差が比較的小さく、その結果学習補正値の収束値が小さくなり噴射期間への影響が少ないインジェクタを用いた構成に適用する場合は、追加噴射時期の補正を省略して簡素な構成としてもよい。このような構成は図7におけるS11−5、S11−6を省略することで実現可能である。
以下に、本発明の第二実施形態について説明する。
On the other hand, when applying to a configuration using an injector in which the injection amount error at the time of additional injection is relatively small and the convergence value of the learning correction value is small and the influence on the injection period is small, correction of the additional injection timing is omitted. And it is good also as a simple structure. Such a configuration can be realized by omitting S11-5 and S11-6 in FIG.
The second embodiment of the present invention will be described below.

図8に、本実施形態の構成概略を示す。第一実施形態との相違は、空燃比検出手段である空燃比センサ14が排気通路集合部に設けられている点である。その他の構成及び制御方法については前記第一実施形態と同様である。
図4のS12に該当する気筒別空燃比LMDnの検出は、例えば特許第3357572号などに示された方法により、各気筒からの排気が排気集合部(あるいはその下流)に設けた空燃比検出手段を通過するタイミングを求めることによって行うことができる。このタイミングで空燃比を各気筒からの排気の空燃比を検出し、この検出値をもとに気筒毎に学習を行う。本実施形態では、単一のセンサで各気筒の空燃比を検出するため、制御は複雑になるものの、一方で空燃比検出手段が少なくて済み、センサのレイアウト面、コスト面で有利になるばかりでなく、センサの個体差に起因する気筒別ばらつきが生じないという利点が得られる。
FIG. 8 shows a schematic configuration of the present embodiment. The difference from the first embodiment is that an air-fuel ratio sensor 14 as air-fuel ratio detection means is provided in the exhaust passage collection portion. Other configurations and control methods are the same as those in the first embodiment.
The air-fuel ratio LMDn for each cylinder corresponding to S12 in FIG. 4 is detected by, for example, a method shown in Japanese Patent No. 3357572, etc., and an air-fuel ratio detection means in which exhaust from each cylinder is provided in the exhaust collecting part (or downstream thereof) This can be done by obtaining the timing of passing through. At this timing, the air-fuel ratio of the exhaust gas from each cylinder is detected, and learning is performed for each cylinder based on the detected value. In this embodiment, since the air-fuel ratio of each cylinder is detected by a single sensor, the control is complicated, but on the other hand, the number of air-fuel ratio detection means is small, which is advantageous in terms of sensor layout and cost. In addition, there is an advantage that there is no variation among cylinders due to individual differences of sensors.

その他、図示等はしないが、下記のような実施形態も可能である。下記いずれの実施形態においても、インジェクタ個体特性に応じてこれらの構成の中から最適なものを組み合わせることで、本発明の利点を十分に活かしつつ、演算負荷並びにコストを削減することが可能である。
まず、1回噴射で用いる領域において比較的気筒間にばらつきが少ない場合には、全気筒の平均空燃比を用いて全気筒一律に1回噴射の学習を行うことも可能である。これにより、1回噴射用のマップは1つで足りるという利点が得られる。
In addition, although not illustrated, the following embodiments are also possible. In any of the embodiments described below, it is possible to reduce the computation load and cost while fully utilizing the advantages of the present invention by combining the optimal ones among these configurations according to the injector individual characteristics. .
First, when there is relatively little variation among cylinders in the region used for single injection, it is possible to learn single injection uniformly for all cylinders using the average air-fuel ratio of all cylinders. Thereby, the advantage that one map for single injection is sufficient is obtained.

また、インジェクタ個体特性のばらつきが小さい場合には、追加噴射の学習についても全気筒の平均値を用いることも可能である。これにより、追加噴射用の学習マップも1つで足りるという利点が得られる。
あるいは、1回噴射と追加噴射では使用するパルス幅の領域が異なるため、同一の学習マップを領域によって使い分け、ECUのRAM領域を節約することも可能である。
In addition, when the variation in individual injector characteristics is small, it is also possible to use the average value of all cylinders for learning of additional injection. Thereby, the advantage that one learning map for additional injection is sufficient is acquired.
Alternatively, since the region of the pulse width to be used is different between the single injection and the additional injection, it is possible to use the same learning map depending on the region to save the RAM area of the ECU.

本発明の第一実施形態における構成図Configuration diagram in the first embodiment of the present invention 本発明の第一実施形態における空燃比センサの配置図Arrangement of air-fuel ratio sensor in the first embodiment of the present invention 本発明の第一実施形態における燃料噴射制御のフローチャートFlow chart of fuel injection control in the first embodiment of the present invention. 本発明の第一実施形態における燃料噴射制御のフローチャートFlow chart of fuel injection control in the first embodiment of the present invention. 本発明の第一実施形態における燃料噴射の基本パルス幅を算出する フローチャートThe flowchart which calculates the basic pulse width of the fuel injection in 1st embodiment of this invention インジェクタにおけるパルス幅と燃料噴射量との関係の特性図Characteristic diagram of the relationship between pulse width and fuel injection amount in injectors 本発明の第一実施形態における燃料噴射時期及び点火時期制御の フローチャートFlowchart of fuel injection timing and ignition timing control in the first embodiment of the present invention 本発明の第二実施形態における構成図The block diagram in 2nd embodiment of this invention

符号の説明Explanation of symbols

13.排気通路
14.空燃比センサ
13. Exhaust passage 14. Air-fuel ratio sensor

Claims (12)

成層燃焼で1サイクル中に複数回の燃料噴射を行うモードを有し、空燃比検出値に応じて目標空燃比にフィードバック制御しつつ燃料噴射パルス幅を調整し、この燃料噴射パルス幅の調整量に基づいて燃料噴射パルス幅と燃料噴射量の関係を学習して学習補正値を求める学習手段を有する筒内直接噴射式火花点火内燃機関において、
前記成層燃焼1サイクル中に複数回燃料噴射を行うモードでは、複数回の燃料噴射に対し各々独立して学習された異なる学習補正値を反映させることを特徴とする筒内直接噴射式内燃機関の燃料噴射制御装置。
There is a mode in which fuel injection is performed a plurality of times in one cycle by stratified combustion, and the fuel injection pulse width is adjusted while feedback controlling to the target air-fuel ratio according to the detected air-fuel ratio, and the adjustment amount of this fuel injection pulse width In a cylinder direct injection spark ignition internal combustion engine having learning means for learning a relationship between a fuel injection pulse width and a fuel injection amount based on
In a mode in which fuel injection is performed a plurality of times during one cycle of stratified combustion, a different learning correction value learned independently is reflected for a plurality of fuel injections. Fuel injection control device.
前記成層燃焼1サイクル中に複数回燃料噴射を行うモードにおいて学習を行い、求めた学習補正値を、1サイクル中の複数回の燃料噴射のうち最もパルス幅の短い噴射に反映させるようにしたことを特徴とする請求項1に記載の筒内直接噴射式内燃機関の燃料噴射制御装置。 Learning is performed in a mode in which fuel injection is performed a plurality of times during one cycle of stratified combustion, and the obtained learning correction value is reflected in the injection having the shortest pulse width among the plurality of fuel injections in one cycle. 2. The fuel injection control device for a direct injection type internal combustion engine according to claim 1, wherein: 前記成層燃焼1サイクル中に複数回燃料噴射を行うモードにおいて学習を行う場合、最もパルス幅の短い燃料噴射を除くパルス幅の噴射には、1サイクル中に1回燃料噴射を行うモードにおいて求めた学習補正値を反映させることを特徴とする請求項2に記載の筒内直接噴射式内燃機関の燃料噴射制御装置。 When learning is performed in a mode in which fuel injection is performed a plurality of times during one cycle of the stratified combustion, injection with a pulse width excluding fuel injection with the shortest pulse width is obtained in a mode in which fuel injection is performed once in one cycle. The fuel injection control device for a direct injection type internal combustion engine according to claim 2, wherein the learning correction value is reflected. 前記成層燃焼1サイクル中に複数回燃料噴射を行うモードにおける学習は、前記1サイクル中に1回燃料噴射を行うモードにおける学習が完了した後に行うことを特徴とする請求項3に記載の筒内直接噴射式内燃機関の燃料噴射制御装置。 4. The in-cylinder according to claim 3, wherein learning in a mode in which fuel injection is performed a plurality of times during one cycle of stratified combustion is performed after learning in a mode in which fuel injection is performed once during the one cycle is completed. A fuel injection control device for a direct injection internal combustion engine. 前記学習補正値は、異なる燃料噴射パルス幅毎に設定されることを特徴とする請求項1〜請求項4のいずれか1つに記載の筒内直接噴射式内燃機関の燃料噴射制御装置。 The fuel injection control device for a direct injection type internal combustion engine according to any one of claims 1 to 4, wherein the learning correction value is set for each different fuel injection pulse width. 前記学習補正値は、異なる燃料圧力毎に設定されることを特徴とする請求項1〜請求項5のいずれか1つに記載の筒内直接噴射式内燃機関の燃料噴射制御装置。 6. The fuel injection control device for a direct injection type internal combustion engine according to any one of claims 1 to 5, wherein the learning correction value is set for each different fuel pressure. 前記学習補正値は前記内燃機関の各気筒毎に求めることを特徴とする請求項1〜請求項6のいずれか1つに記載の筒内直接噴射式内燃機関の燃料噴射制御装置。   The fuel injection control device for a direct injection type internal combustion engine according to any one of claims 1 to 6, wherein the learning correction value is obtained for each cylinder of the internal combustion engine. 各気筒の排気通路に各々空燃比検出手段を設け、各手段からの空燃比検出値に応じて対応する各気筒の学習を行うことを特徴とする請求項7に記載の筒内直接噴射式内燃機関の燃料噴射制御装置。   8. An in-cylinder direct injection internal combustion engine according to claim 7, wherein air-fuel ratio detection means is provided in each exhaust passage of each cylinder, and learning is performed for each cylinder corresponding to the air-fuel ratio detection value from each means. Engine fuel injection control device. 各気筒からの排気通路の集合部あるいはその下流に空燃比検出手段を設け、該手段からの空燃比検出値に応じて、気筒毎に学習を行うことを特徴とする請求項7に記載の筒内直接噴射式内燃機関の燃料噴射制御装置。 8. The cylinder according to claim 7, wherein an air-fuel ratio detection means is provided at a collection portion of the exhaust passage from each cylinder or downstream thereof, and learning is performed for each cylinder in accordance with an air-fuel ratio detection value from the means. A fuel injection control device for an internal direct injection internal combustion engine. 各気筒からの排気が空燃比検出手段を通過する時期に対応する所定タイミングで空燃比を検出し、その検出値に応じて当該気筒の学習補正値を求めることを特徴とする請求項9に記載の筒内直接噴射式内燃機関の燃料噴射制御装置。 10. The air-fuel ratio is detected at a predetermined timing corresponding to the timing when exhaust gas from each cylinder passes through the air-fuel ratio detection means, and a learning correction value for the cylinder is obtained according to the detected value. In-cylinder direct injection internal combustion engine fuel injection control device. 前記成層燃焼1サイクル中に複数回燃料噴射を行うモードにおいて求めた学習補正値に応じて、1サイクル中の複数回の燃料噴射のうち最もパルス幅の短い噴射の開始時期を調節することを特徴とする請求項1〜請求項10のいずれか1つに記載の筒内直接噴射式内燃機関。 The start timing of the injection with the shortest pulse width among the plurality of fuel injections in one cycle is adjusted according to the learning correction value obtained in the mode in which fuel injection is performed a plurality of times during one cycle of stratified combustion. The in-cylinder direct injection internal combustion engine according to any one of claims 1 to 10. 前記成層燃焼1サイクル中に複数回燃料噴射を行うモードにおいて求めた学習補正値に応じて、1サイクル中の複数回の燃料噴射のうち最もパルス幅の短い噴射の開始時期を調節する際、該噴射の終了時期が学習補正前と略同時期となるように調節することを特徴とする請求項11に記載の筒内直接噴射式内燃機関の燃料噴射制御装置。 When adjusting the start timing of the shortest pulse width among the plurality of fuel injections in one cycle according to the learning correction value obtained in the mode in which the fuel injection is performed a plurality of times during the stratified combustion one cycle, The fuel injection control device for a direct injection type internal combustion engine according to claim 11, wherein the end timing of injection is adjusted so as to be substantially the same as that before learning correction.
JP2004367380A 2004-12-20 2004-12-20 Fuel injection control device for cylinder direct injection type internal combustion engine Pending JP2006170165A (en)

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Cited By (7)

* Cited by examiner, † Cited by third party
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JP2008014152A (en) * 2006-07-03 2008-01-24 Denso Corp Learning method of injection characteristic and fuel injection control device
JP2009057909A (en) * 2007-08-31 2009-03-19 Denso Corp Fuel injection control device of internal combustion engine
JP2010025091A (en) * 2008-07-24 2010-02-04 Hitachi Ltd Control device of cylinder injection type internal combustion engine
US8437944B2 (en) 2009-09-04 2013-05-07 Denso Corporation Fuel injection device of internal combustion engine
JP2014510219A (en) * 2010-12-24 2014-04-24 デルファイ・テクノロジーズ・インコーポレーテッド Method for controlling an internal combustion engine
JP2016079937A (en) * 2014-10-21 2016-05-16 株式会社デンソー Control apparatus
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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008014152A (en) * 2006-07-03 2008-01-24 Denso Corp Learning method of injection characteristic and fuel injection control device
JP4682935B2 (en) * 2006-07-03 2011-05-11 株式会社デンソー Injection characteristic learning method and fuel injection control device
JP2009057909A (en) * 2007-08-31 2009-03-19 Denso Corp Fuel injection control device of internal combustion engine
JP4501974B2 (en) * 2007-08-31 2010-07-14 株式会社デンソー Fuel injection control device for internal combustion engine
JP2010025091A (en) * 2008-07-24 2010-02-04 Hitachi Ltd Control device of cylinder injection type internal combustion engine
US8437944B2 (en) 2009-09-04 2013-05-07 Denso Corporation Fuel injection device of internal combustion engine
JP2014510219A (en) * 2010-12-24 2014-04-24 デルファイ・テクノロジーズ・インコーポレーテッド Method for controlling an internal combustion engine
JP2016079937A (en) * 2014-10-21 2016-05-16 株式会社デンソー Control apparatus
JP2016180330A (en) * 2015-03-23 2016-10-13 株式会社デンソー Valve timing control system

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