JPH0733783B2 - Air-fuel ratio controller for internal combustion engine - Google Patents
Air-fuel ratio controller for internal combustion engineInfo
- Publication number
- JPH0733783B2 JPH0733783B2 JP15612187A JP15612187A JPH0733783B2 JP H0733783 B2 JPH0733783 B2 JP H0733783B2 JP 15612187 A JP15612187 A JP 15612187A JP 15612187 A JP15612187 A JP 15612187A JP H0733783 B2 JPH0733783 B2 JP H0733783B2
- Authority
- JP
- Japan
- Prior art keywords
- injection
- cylinder
- asynchronous injection
- air
- amount
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） この発明は燃料噴射式機関の空燃比制御装置、特に加速
時に非同期噴射を行うものに関する。Description: TECHNICAL FIELD The present invention relates to an air-fuel ratio control device for a fuel injection engine, and more particularly to an air-fuel ratio control device that performs asynchronous injection during acceleration.
（従来の技術） 加速時には、回転毎（たとえば１回転に１回）の同期噴
射とは別に非同期噴射を行うことにより加速性の向上を
図るものがある。ここに、加速時であるかどうかは、吸
気絞り弁が全閉位置でONとなるスイッチ（アイドルスイ
ッチ）からの信号がONからOFFに変化することを捕らえ
て、あるいは絞り弁開度の変化速度が基準レベルを越え
たことを捕らえて加速時であると判定している。(Prior Art) At the time of acceleration, there is a method for improving acceleration performance by performing asynchronous injection separately from synchronous injection for each rotation (for example, once for one rotation). Whether or not the engine is accelerating depends on whether the signal from the switch (idle switch) that turns on the intake throttle valve at the fully closed position changes from ON to OFF, or the rate of change of the throttle valve opening. It is judged that it is during acceleration by catching that the vehicle has exceeded the standard level.
また、非同期噴射量（非同期噴射パルス幅）は冷却水温
TWに応じた値や絞り弁開度の変化速度に応じた値が用い
られている（たとえば特開昭59−200034号公報参照）。The asynchronous injection amount (asynchronous injection pulse width) is the cooling water temperature.
A value according to T W or a value according to the changing speed of the throttle valve opening is used (for example, see Japanese Patent Laid-Open No. 59-200034).
（発明が解決しようとする問題点） ところで、このような装置では、非同期噴射に伴う目標
空燃比（たとえば理論空燃比）からの誤差と、非同期噴
射量の計算に用いられる信号（アイドルスイッチからの
ON−OFF信号、絞り弁開度の変化速度）との相関関係が
薄いため、加速の程度や非同期噴射を行うタイミング
（サイクル位置）が相違すると、目標空燃比からの大き
なばらつきが残る。このため、空燃比が大きくリーン化
あるいはリッチ化すると、失火によるHC排出量の増加を
招いたり、トルク落ちを生じて過渡運転性に悪影響を与
える。また、空燃比がリッチ化することによりCO排出量
が増す。(Problems to be Solved by the Invention) By the way, in such a device, an error from a target air-fuel ratio (for example, a theoretical air-fuel ratio) associated with asynchronous injection and a signal used for calculation of the asynchronous injection amount (from the idle switch)
Since there is little correlation with the ON-OFF signal and the changing speed of the throttle valve opening), if the degree of acceleration or the timing (cycle position) of performing asynchronous injection differs, a large variation from the target air-fuel ratio remains. For this reason, if the air-fuel ratio is made leaner or richer, it causes an increase in the amount of HC emissions due to misfire, or causes a torque drop, which adversely affects the transient drivability. In addition, CO emission increases due to the enrichment of the air-fuel ratio.
この発明はこのような問題点を解決することを目的とす
る。The present invention aims to solve such problems.
（問題点を解決するための手段） この発明は、第１図に示すように、運転条件信号（機関
負荷信号）の変化量に基づいて回転毎の同期噴射とは別
に非同期噴射を行うかどうかを判定する手段１と、非同
期噴射を行うことが判定されたときに前記運転条件信号
の変化量に基づいて気筒別に非同期噴射量（ADDQCn）を
演算する手段２と、同じく非同期噴射を行うことが判定
されたときにその時点のサイクル位置が次の吸気行程か
ら遠いほど小さくなる値を前記非同期噴射量（ADDQCn）
の補正率（GZCYLn）として、少なくとも非同期噴射を行
うことが判定された時点でのシリンダ内吸入負圧の変化
が吸気行程と重ならない気筒について気筒別に演算する
手段３と、この演算された補正率（GZCYLn）にて前記非
同期反射量（ADDQCn）を補正する手段４と、この補正さ
れた非同期噴射量に応じた駆動信号にて気筒別に燃料噴
射弁を駆動する手段５とを設けた。たとえば、運転条件
の変化量とこの変化量に基づく非同期噴射量として、シ
リンダに流入する空気量（以下「シリンダ空気量」と称
す。）の単位周期当たりの変化量（DQCYL）とDQCYLの積
算値が採用される。(Means for Solving Problems) This invention, as shown in FIG. 1, determines whether to perform asynchronous injection separately from synchronous injection for each rotation based on the amount of change in the operating condition signal (engine load signal). And a means 2 for calculating the asynchronous injection amount (ADDQCn) for each cylinder based on the change amount of the operating condition signal when it is determined to perform the asynchronous injection. When the determination is made, a value that becomes smaller as the cycle position at that point becomes farther from the next intake stroke is the asynchronous injection amount (ADDQCn)
As the correction rate (GZCYLn) of the cylinder, at least the means 3 for calculating the cylinder for which the change in the intake negative pressure in the cylinder does not overlap with the intake stroke at the time when it is determined to perform the asynchronous injection, and the calculated correction rate (GZCYLn) is provided with means 4 for correcting the asynchronous reflection amount (ADDQCn), and means 5 for driving the fuel injection valve for each cylinder by a drive signal according to the corrected asynchronous injection amount. For example, the change amount of operating conditions and the asynchronous injection amount based on this change amount, the change amount (DQCYL) per unit cycle of the air amount flowing into the cylinder (hereinafter referred to as "cylinder air amount") and the integrated value of DQCYL. Is adopted.
（作用） 少なくとも非同期噴射を行うことが判定された時点での
シリンダ内吸入負圧の変化が吸気行程と重ならない気筒
についは、非同期噴射のタイミングから次の吸気行程ま
での待ち時間に応じてシリンダに流入する燃料量が相違
する。(Function) For a cylinder in which the change in the intake negative pressure in the cylinder does not overlap with the intake stroke at least when it is determined to perform the asynchronous injection, the cylinder is determined according to the waiting time from the timing of the asynchronous injection to the next intake stroke. The amount of fuel flowing into is different.
こうした吸気系燃料の挙動に注目して、非同期噴射を行
うサイクル位置が噴射直後の吸気行程よりも遠ければ噴
射直後の１回目の吸気行程で吸入される燃料割合が大き
くなるので、小さな値の補正率GZCYLnが、この逆に非同
期噴射を行うサイクル位置が噴射直後の吸気行程に近け
れば、噴射直後の１回目の吸気行程で吸入される燃料割
合が小さくなるので、大きな値の補正率GZCYLnが読み出
されると、各気筒で噴射直後の１回目の吸気行程で吸入
される燃料量が同じになる。Paying attention to such behavior of intake system fuel, if the cycle position for asynchronous injection is farther than the intake stroke immediately after injection, the proportion of fuel that is sucked in the first intake stroke immediately after injection will be large, so correction of a small value On the contrary, if the cycle position for performing asynchronous injection is close to the intake stroke immediately after the injection, the proportion of fuel sucked in the first intake stroke immediately after the injection becomes small, so the correction rate GZCYLn of a large value is read out. Then, the amount of fuel sucked in each cylinder becomes the same in the first intake stroke immediately after injection.
これにより、非同期噴射を行うサイクル位置に拘わらず
噴射直後の吸気行程でシリンダへと吸入される混合気の
空燃比を精度良く与えることができる。As a result, the air-fuel ratio of the air-fuel mixture sucked into the cylinder in the intake stroke immediately after the injection can be accurately given regardless of the cycle position where the asynchronous injection is performed.
（実施例） 第２図は本発明を６気筒機関に適用した一実施例で、気
筒別に燃料噴射を制御するため各気筒の吸気ポート11に
噴射弁10が設けられる。(Embodiment) FIG. 2 is an embodiment in which the present invention is applied to a 6-cylinder engine, and an injection valve 10 is provided in an intake port 11 of each cylinder to control fuel injection for each cylinder.
12は吸気絞り弁14の開度（TVO）を検出するセンサ（絞
り弁開度センサ）、15はクランク角の基準位置と単位角
度に応じた信号を出力するセンサ（クランク角セン
サ）、16は機関冷却水温TWを検出するセンサ、17は理論
空燃比だけでなくそれ以外の空燃比についても広範囲に
検出するセンサである。ここに、クランク角センサ15か
らの信号にて機関回転速度Ｎとサイクル位置が検出され
る。なお、絞り弁14をバイパスする通路19には、当該通
路19の流路面積を可変とする電磁弁（アイドル制御弁）
20が介装されている。12 is a sensor (throttle valve opening sensor) that detects the opening (TVO) of the intake throttle valve 14, 15 is a sensor (crank angle sensor) that outputs a signal according to the crank angle reference position and unit angle, and 16 is A sensor for detecting the engine cooling water temperature T W , and 17 is a sensor for widely detecting not only the theoretical air-fuel ratio but also other air-fuel ratios. Here, the engine speed N and the cycle position are detected by the signal from the crank angle sensor 15. The passage 19 that bypasses the throttle valve 14 has a solenoid valve (idle control valve) that allows the passage area of the passage 19 to be variable.
20 are installed.
これらセンサからの信号が入力されるコントロールユニ
ット18では、これらの信号に基づいて目標空燃比の混合
気が得られるように回転毎の同期噴射と加速時の非同期
噴射を行う。ここに、コントロールユニット18は主にマ
イクロコンピュータから構成され、第１図に示す手段１
ないし５の全機能を有し、以下に第３図に示す流れ図を
参照しながらその機能を説明する。The control unit 18 to which the signals from these sensors are input performs the synchronous injection for each rotation and the asynchronous injection at the time of acceleration so as to obtain the air-fuel mixture having the target air-fuel ratio based on these signals. Here, the control unit 18 is mainly composed of a microcomputer, and means 1 shown in FIG.
It has all the functions of Nos. 5 to 5 and will be described below with reference to the flowchart shown in FIG.
加速時の非同期噴射は要求がある場合に限って行えば足
りるので、割込み処理とされる。第３図はこの割込み処
理のルーチンで、一定周期（たとえば10msec毎）で実行
される。まずステップ31では前回と今回にそれぞれ読み
込んだシリンダ空気量（QCYL-1とLCYL）の差よりシリン
ダ空気量の単位周期当たりの変化量（DQCTYL）を求め
る。ここに、記号の後に付す「−１」により前回の値で
あることを意味させるものとする。以下においてもこの
符号を使用する。Since the asynchronous injection at the time of acceleration need only be performed when requested, it is treated as an interrupt. FIG. 3 is a routine of this interrupt processing, which is executed at a constant cycle (for example, every 10 msec). First, in step 31, the change amount (DQCTYL) of the cylinder air amount per unit cycle is obtained from the difference between the cylinder air amounts (QCYL -1 and LCYL) read in the previous time and this time. Here, "-1" added after the symbol means that the value is the previous value. This code will also be used in the following.
QCYLは、たとえば絞り弁開度（TVO）から絞り弁部の定
常流量（QH）を求め、これを絞り弁部からシリンダまで
の供給遅れを考慮する係数（K2）にて補正することによ
り、すなわち QCYL＝QH×K2＋QCYL-1×（１−K2） にて求められる。こうして求めたQCYLによれば、吸気脈
動に影響されることなく（過渡時にも精度良くシリンダ
空気量が測定される。求めかたの詳細は先願（特開昭61
−177949号）に述べているところであるのでここでは省
略する。なお、QCYL相当量に絞り弁下流のブースト圧が
ある。QCYL is calculated by, for example, obtaining the steady flow rate (Q H ) of the throttle valve section from the throttle valve opening (TVO) and correcting this with a coefficient (K 2 ) that considers the supply delay from the throttle valve section to the cylinder. , that is, determined in QCYL = Q H × K 2 + QCYL -1 × (1-K 2). According to the QCYL thus obtained, the cylinder air amount can be accurately measured even during a transition without being affected by the intake pulsation.
No. 177949), so it is omitted here. There is boost pressure downstream of the throttle valve that corresponds to QCYL.
続いて、DQCYLの精算値（ADDQCn）を気筒別に求める
（ステップ32）。これは前回までのDQCYLの精算値（ADD
QCn-1）にDQCYLを加算することによる。なお、ｎにて気
筒番号を意味させるものとする。したがって、６気筒機
関ではｎは１ないし６の整数である。以下の説明におい
て記号の最後にｎを付すときは同じ意味で使用する。Next, the DQCYL adjustment value (ADDQCn) is calculated for each cylinder (step 32). This is the DQCYL settlement value (ADD
By adding DQCYL to QCn -1 ). It should be noted that n means a cylinder number. Therefore, in a 6-cylinder engine, n is an integer from 1 to 6. In the following description, when n is added to the end of a symbol, they have the same meaning.
ここに、ADDQCnは前回の非同期噴射時からの空気変化量
の合計としての意味をもち、非同期噴射パルス幅を決定
する基本値となる。ここに、積算値とする理由は、DQCY
Lそのものよりも加速の程度に良く対応するからであ
る。たとえば、緩やかな加速が継続する場合には、小さ
な変化量でもある程度たまった段階で非同期噴射を行う
ようにするほうが、DQCYLそのものが小さいからとして
無視するよりも良いのである。Here, ADDQCn has the meaning as the total of the air change amount from the previous asynchronous injection, and is a basic value that determines the asynchronous injection pulse width. Here, the reason for the integrated value is DQCY
This is because it corresponds to the degree of acceleration better than L itself. For example, when gradual acceleration continues, it is better to perform asynchronous injection at a stage where a small amount of change has accumulated, rather than to ignore it because DQCYL itself is small.
次に、ステップ33と34で非同期噴射を行うかどうかを判
定する。非同期噴射の成立条件は、 （ｉ）DQCYLが２回続けて判定レベル（LKTIDQ）以上で
あること、 （ii）ADDQCnが総ての気筒について判定レベル（LKTIA
Q）以上であること の両方が成立することである。ここに、（ｉ）で２回以
上としたのは１回であると電気的ノイズの侵入による誤
作動にて成立することがあるので、これを防止するため
である。Next, in steps 33 and 34, it is determined whether to perform asynchronous injection. The conditions for establishing asynchronous injection are (i) DQCYL is equal to or higher than the determination level (LKTIDQ) twice in a row, and (ii) ADDQCn is the determination level (LKTIA) for all cylinders.
Q) It means that both of the above are true. Here, the reason (i) is set twice or more is to prevent it because once it occurs once, it may be established due to malfunction due to intrusion of electrical noise.
そして、両方とも成立した場合には、ステップ38で、非
同期噴射を行うサイクル位置に応じてROMに記憶させて
いるテーブルデータの参照にて気筒別補正率GZCYLnを求
める。GZCYLnの特性例を第５図に破線で示すと、非同期
噴射を行うサイクル位置が噴射直後の吸気行程から遠く
なるほど小さな値が付与される。なお、非同期噴射の判
定から非同期噴射を行うまでの期間は短いものであり、
判定時期と非同期噴射を行う時期とをほぼ同様に扱う。If both are satisfied, in step 38, the cylinder-by-cylinder correction rate GZCYLn is obtained by referring to the table data stored in the ROM according to the cycle position at which the asynchronous injection is performed. When a characteristic example of GZCYLn is shown by a broken line in FIG. 5, a smaller value is given as the cycle position for performing asynchronous injection becomes farther from the intake stroke immediately after injection. The period from the determination of asynchronous injection to the execution of asynchronous injection is short,
The determination timing and the timing of performing asynchronous injection are treated in substantially the same way.
GZCYLnは非同期噴射が行なわれるサイクル位置から吸気
行程までのクランク角差に応じて吸気系燃料の挙動が相
違するので、これを考慮するために導入される値であ
る。すなわち、同期噴射であれ非同期噴射であれ、噴射
弁より噴射された燃料は噴射直後の１回目の吸気行程で
総てがシリンダへと吸入されることはなく、一度吸気管
壁に付着し、その中から蒸発した判定割合の燃料だけが
吸入される。ここに、噴射燃料のうち噴射直後の１回目
の吸気行程で吸入される燃料割合を直接率Ｚとおき、暖
機後におけるＺの特性を第６図に示すと、噴射時より吸
気行程までの待ち時間が長いほどＺが大きくなってい
る。なお、本特性は噴射弁のパルス幅をステップ変化さ
せて排機空燃比の変化から求めたものである。GZCYLn is a value introduced in order to take account of this because the behavior of the intake system fuel differs depending on the crank angle difference from the cycle position where asynchronous injection is performed to the intake stroke. That is, regardless of whether the fuel injection is synchronous injection or asynchronous injection, all of the fuel injected from the injection valve is not sucked into the cylinder in the first intake stroke immediately after injection, and once adheres to the intake pipe wall, Only the fuel of the determined ratio evaporated from the inside is sucked. Here, the proportion of fuel in the injected fuel that is taken in in the first intake stroke immediately after injection is set as the direct rate Z, and the characteristic of Z after warm-up is shown in FIG. The longer the waiting time, the larger Z becomes. The characteristic is obtained from the change in the exhaust air-fuel ratio by changing the pulse width of the injection valve in steps.
同図より吸気行程までの待ち時間、すなわち噴射時のサ
イクル位置によらず非同期噴射量を一定として、Ｚが大
きい位置で噴射すると、空燃比がリッチ化し、この逆に
Ｚが小さい位置で噴射すると、空燃比がリーン化する割
合が生ずることがわかる。したがって、こうしたＺの特
性を考慮するならば、噴射を行うサイクル位置をパラメ
ータとしてＺの特性に応じた補正率（GZCYLn）を導入す
る必要があるのである。As shown in the figure, when the asynchronous injection amount is constant regardless of the waiting time until the intake stroke, that is, the injection cycle position, when injection is performed at a position where Z is large, the air-fuel ratio becomes rich, and conversely when injection is performed at a position where Z is small. It can be seen that the air-fuel ratio becomes lean. Therefore, if such Z characteristics are taken into consideration, it is necessary to introduce a correction factor (GZCYLn) according to the Z characteristics using the cycle position at which injection is performed as a parameter.
次に、ステップ40で気筒別の非同期噴射パルス幅（KTIN
Jn）をKTINJn＝ADDQCn×GZCYLn＋Tsにて気筒別に順次求
める。ただし、Tsは無効パルス幅である。そして、総て
の気筒についてはKTINJnの計算後直ぐにKTINJnに基づく
非同期噴射を行い、最後に次の非同期噴射に備えてADDQ
Cnを総て０にしておくことで本ルーチンを終了する（ス
テップ41,42）。Next, in step 40, the asynchronous injection pulse width (KTIN
Jn) is sequentially calculated for each cylinder by KTINJn = ADDQCn × GZCYLn + Ts. However, Ts is an invalid pulse width. Then, for all the cylinders, asynchronous injection based on KTINJn is performed immediately after the calculation of KTINJn, and finally ADDQ in preparation for the next asynchronous injection.
This routine is ended by setting all Cn to 0 (steps 41 and 42).
の例によれば、補正率GZCYLnとして、非同期噴射を行う
サイクル位置が噴射直後の吸気行程よりも遠ければ小さ
な値が、この逆に近ければ大きな値が読み出され、吸気
系燃料の挙動に応じたものとなる。非同期噴射を行うサ
イクル位置が噴射直後の吸気行程よりも遠ければ噴射直
後の１回目の吸気行程で吸入される燃料割合が大きくな
るので、小さな値の補正率GZCHYLnが、この逆に非同期
噴射を行うサイクル位置が噴射直後の吸気行程に近いと
きは噴射直後の１回目の吸気行程で吸入される燃料割合
が小さくなるので、大きな値の補正率GZCYLnが読み出さ
れ、いずれの気筒も噴射直後の１回目の吸気行程で吸入
される燃料量が同じになるのである。これによって、噴
射位置に拘わらず噴射直後の吸気行程でシリンダへと吸
入される混合気の空燃比が精度良く与えられる。According to the example, as the correction factor GZCYLn, a small value is read if the cycle position for asynchronous injection is farther than the intake stroke immediately after injection, and a large value is read if the cycle position is close to the opposite, and it is determined according to the behavior of the intake system fuel. It becomes a thing. If the cycle position where asynchronous injection is performed is farther than the intake stroke immediately after injection, the proportion of fuel that is sucked in the first intake stroke immediately after injection is large, so a small correction factor GZCHYLn performs the asynchronous injection in reverse. When the cycle position is close to the intake stroke immediately after the injection, the proportion of fuel that is sucked in the first intake stroke immediately after the injection becomes small, so a large correction factor GZCYLn is read out, and all cylinders have 1 The amount of fuel taken in is the same in the intake stroke of the first time. As a result, the air-fuel ratio of the air-fuel mixture sucked into the cylinder in the intake stroke immediately after the injection is accurately provided regardless of the injection position.
たとえば、第11図と第12図にそれぞれ従来例とこの例の
加速時（正確には緩加速時）の空燃比誤差を示すと、第
11図の従来例では誤差が上下に振れているばかりでな
く、ばらつきも生じているが、これに対ししてこの例に
よれば、誤差とばらつきがともに改善されている。な
お、同図のMRは、目標空燃比からの誤差率を示し、上に
振れるほどリーン化し、この逆に下に振れるほどリッチ
化することを意味する。後述する第13図ないし第16図で
も同様である。For example, FIGS. 11 and 12 show the air-fuel ratio error during acceleration (accurately, during gentle acceleration) of the conventional example and this example, respectively.
In the conventional example shown in FIG. 11, not only the error fluctuates up and down, but also variations occur. In contrast, according to this example, both the errors and variations are improved. Note that MR in the figure indicates an error rate from the target air-fuel ratio, meaning that it leans as it swings upward, and conversely becomes rich as it swings downward. The same applies to FIGS. 13 to 16 described later.
また、吸気系燃料の挙動は冷却水温TWの影響を大きく受
けるので、TWに関する補正係数（非同期噴射水温補正係
数）をも導入している。ステップ36と40に示すGZTWがそ
れで、GZTWはROMに記憶しているテーブルデータの参照
にて求められる。GZTWの特性例を第４図に示す。Since the behavior of the intake system fuel is greatly affected by the cooling water temperature T W , a correction coefficient for T W (asynchronous injection water temperature correction coefficient) is also introduced. This is the GZTW shown in steps 36 and 40, and the GZTW can be obtained by referring to the table data stored in the ROM. Figure 4 shows an example of the characteristics of GZTW.
この場合のKTINJnは KTINJn＝ADDQCn×GZTW×GZCYLn＋Ts である。In this case, KTINJn is KTINJn = ADDQCn x GZTW x GZCYLn + Ts.
一方、急加速時になると、第11図と第12図に示した緩加
速時と事態が相違してくる。第13図と第14図に急加速時
における従来例とこの例（ステップ38で参照したテーブ
ルデータをそのまま用いた場合）の空燃比誤差を示す
と、従来例の第13図との比較によればこの例の第14図で
も加速初期のリーン化が低減されているといえるが、大
きなばらつきにつては改善されていない。On the other hand, during sudden acceleration, the situation is different from that during slow acceleration shown in FIGS. 11 and 12. Figures 13 and 14 show the air-fuel ratio error between the conventional example and this example (when the table data referenced in step 38 is used as is) during sudden acceleration. For example, in Fig. 14 of this example, it can be said that leaning at the initial stage of acceleration is reduced, but large variations are not improved.
この空燃比のばらつきの原因は、気筒間で吸気ポート部
の空気流速が相違するためである。吸気行程中の吸入負
圧の変化が大きくなる急加速時には、定常や緩加速時と
は異なりピストン動作に伴う流速に、シリンダ内の圧力
変化（ほぼ吸気管圧力変化に近い。）に伴う流速が上乗
せされるために、ポート部流速が他の気筒よりも高くな
る気筒があるからである。急加速時におけるポート部流
速の予測例を第７図に示すと、１番ないし３番気筒では
シリンダ内圧力変化が吸気行程と重なる期間があり、そ
の間ハッチングで示す分だけ流速が４番ないし６番気筒
よりも大きい。このため、ポート部流速が高い気筒にお
いては吸気管壁に付着した燃料の蒸発が他の気筒よりも
促進されるためか、Ｚが大きくなる傾向が見られた。そ
して、これが気筒間の空燃比のばらつきを引き起こして
いたと推論される。The cause of the variation in the air-fuel ratio is that the air flow velocity in the intake port portion differs between the cylinders. At the time of sudden acceleration during which the change in the suction negative pressure during the intake stroke becomes large, the flow rate accompanying the piston movement is different from the flow rate associated with the piston pressure change (almost close to the intake pipe pressure change), unlike during steady or slow acceleration. This is because there is a cylinder in which the port flow velocity is higher than that of the other cylinders due to the addition. FIG. 7 shows an example of predicting the flow velocity at the port at the time of sudden acceleration. In the 1st to 3rd cylinders, there is a period during which the pressure change in the cylinder overlaps with the intake stroke. It is bigger than the No. cylinder. Therefore, in the cylinder having a high port portion flow velocity, Z tends to increase because the evaporation of the fuel adhering to the intake pipe wall is promoted more than in the other cylinders. Then, it is inferred that this caused the variation of the air-fuel ratio among the cylinders.
したがって、シリンダ内吸入負圧の変化が吸気行程と重
なるタイミングの気筒においては第５図の実線で示すよ
うに補正率を予め小さくしておくことが効果的な対策と
なる。Therefore, in the cylinder at the timing when the change in the intake negative pressure in the cylinder overlaps with the intake stroke, it is an effective measure to reduce the correction rate in advance as shown by the solid line in FIG.
そこで、第２の実施例では、気筒別補正率として緩加速
用と急加速用の２種類を用意し、運転条件の変化により
切り換える構成を付加する。たとえば、第３図において
ステップ37と39でDQCYLと気筒別補正テーブル切換判定
用レベル（LGZCYL）を比較することで急加速であるかど
うかを判定させ、DQCYL≧LGZCYLである場合は急加速用
のテーブルデータを参照し、そのデータをGZCYLnとする
のである。なお、DQCYL＜LGZCYLである場合に参照する
テーブルデータは緩加速用となる。また、第８図に第１
図と対比させた構成図を示す。Therefore, in the second embodiment, two types of correction rates for each cylinder are prepared, one for slow acceleration and the other for rapid acceleration, and a configuration is added in which switching is performed according to changes in operating conditions. For example, in FIG. 3, in steps 37 and 39, it is determined whether or not the acceleration is rapid by comparing the DQCYL and the cylinder correction table switching determination level (LGZCYL). If DQCYL ≧ LGZCYL, the acceleration is determined. The table data is referred to and that data is set as GZCYLn. The table data referred to when DQCYL <LGZCYL is for slow acceleration. Also, as shown in FIG.
The block diagram contrasted with the figure is shown.
これにより、ポート部流速の気筒間の相違に伴う空燃比
のばらつきをなくすことができる。第15図はこの場合の
特性を示し、第14図に示すよりも空燃比のばらつきが減
少しているのがわかる。As a result, it is possible to eliminate the variation in the air-fuel ratio due to the difference in the port flow velocity between the cylinders. FIG. 15 shows the characteristics in this case, and it can be seen that the variation in the air-fuel ratio is smaller than that shown in FIG.
次に、第９図は第３の実施例で、第３図との相違はステ
ップ51を加えた点である。なお、ステップ31から39まで
は省略する。Next, FIG. 9 shows a third embodiment, which is different from FIG. 3 in that step 51 is added. Note that steps 31 to 39 are omitted.
ステップ51は、気筒別非同期噴射量過大分の積算値（ER
ACIn）を ERACIn＝ERACIn-1＋ADDQCn×（GZCYLn−GZCYLP） にて求める。これは前回の非同期噴射時までの積算値
（ERACIn-1）に、新たな過大分（値として負の場合は過
少分である。）を意味するADDQCn×（GZCYLn−GZCYLP）
を加算することで求めるものである。ここで、GZCYLPは
新たな過大分が零となる場合の補正率（基準補正率）で
ある。その値（定数）としては、燃料噴射の狙い場所
（吸気弁またはポート壁等）や同期噴射の噴射サイクル
位置にて異なるが、1.0ないし2.0の間の値が目安とな
る。In step 51, the integrated value (ER
ACIn) is calculated by ERACIn = ERACIn -1 + ADDQCn x (GZCYLn-GZCYLP). This means ADDQCn x (GZCYLn-GZCYLP), which means a new excess (if the value is negative, it is too small) in the integrated value (ERACIn -1 ) up to the previous asynchronous injection.
It is obtained by adding. Here, GZCYLP is a correction rate (reference correction rate) when the new excess becomes zero. The value (constant) varies depending on the target location of fuel injection (such as the intake valve or port wall) and the injection cycle position of synchronous injection, but a value between 1.0 and 2.0 is a standard.
そして、このERACInを、第10図に示す同期噴射ルーチン
と反映させる。同図は回転同期の燃料噴射パルス幅（い
わゆるTi）の計算ルーチンであり、気筒別の燃料噴射パ
ルス幅Tinを、 Tin＝Tp×COEF×α−ERACIn＋Ts にて求める（ステップ61）。また、Tinに基づく同期噴
射を行った後、ERACIn＝０として次回の非同期噴射と同
期噴射に備えさせる（ステップ62）。ただし、Tpは基本
パルス幅、COEFは各種補正係数の総和、αはフィードバ
ック補正係数であり、これらの記号はＬ−ジェトロニッ
ク方式において従来から用いられている値と同じであ
る。Then, this ERACIn is reflected in the synchronous injection routine shown in FIG. This drawing is a routine for calculating a fuel injection pulse width (so-called Ti) in rotation synchronization, and the fuel injection pulse width Tin for each cylinder is obtained by Tin = Tp × COEF × α−ERACIn + Ts (step 61). After performing the synchronous injection based on Tin, ERACIn = 0 is set to prepare for the next asynchronous injection and synchronous injection (step 62). However, Tp is the basic pulse width, COEF is the sum of various correction coefficients, and α is the feedback correction coefficient, and these symbols are the same as those conventionally used in the L-Jetronic system.
この例は非同期噴射とその後の同期噴射とを関連付けて
制御するものである。たとえば、急加速時に非同期噴射
量を大きくして噴射直後の吸気行程において空燃比制御
を高い精度とすることができても、シリンダに吸入され
ずに残った燃料分にてその次の吸気行程では壁流分が増
大するので、非同期噴射と関係なく同期噴射を行うとす
れば空燃日はリッチ化する。In this example, asynchronous injection and subsequent synchronous injection are associated and controlled. For example, even if the asynchronous injection amount can be increased at the time of sudden acceleration and the air-fuel ratio control can be made highly accurate in the intake stroke immediately after the injection, the amount of fuel remaining without being sucked into the cylinder causes a subsequent intake stroke. Since the wall flow amount increases, if the synchronous injection is performed regardless of the asynchronous injection, the air-fuel day becomes rich.
そこで、非同期噴射に伴う過大分だけ次の同期噴射で少
なく供給することにより、空燃比がリッチ化することを
防止するのである。これによれば、非同期噴射直後の吸
気行程を１回目として２回目以降の吸気行程において第
16図に示すように空燃比のリッチ化が改善される。Therefore, by supplying a small amount in the next synchronous injection by an excessive amount due to the asynchronous injection, it is possible to prevent the air-fuel ratio from becoming rich. According to this, the intake stroke immediately after the asynchronous injection is set as the first intake stroke, and the intake stroke after the second intake stroke is
As shown in Fig. 16, the enrichment of the air-fuel ratio is improved.
なお、ポート部流速が大きな気筒の場合には他の気筒よ
りも非同期噴射量を減少することにより逆に２回目以降
の吸気行程において壁流分に燃料が余分に奪われる分空
燃比がリーン化するが、これについても防止されること
はいうまでもない。In the case of a cylinder having a high port flow velocity, the amount of asynchronous injection is reduced as compared with other cylinders, and conversely, the air-fuel ratio is leaner in which the fuel is excessively taken away by the wall flow in the second and subsequent intake strokes. However, it goes without saying that this is also prevented.
（発明の効果） 以上説明したように、この発明は非同期噴射を行うこと
が判定されたときにその時点のサイクル位置が次の吸気
行程から遠いほど小さくなる値を非同期噴射量の補正率
として、少なくとも非同期噴射を行うことが判定された
時点でのシリンダ内吸入負圧の変化が吸気行程と重なら
ない気筒について気筒別に演算し、この演算された補正
率にて前記非同期噴射量を補正する構成としてので、少
なくとも非同期噴射を行うことが判定された時点でのシ
リンダ内吸入負圧の変化が吸気行程と重ならない気筒に
ついて、非同期噴射からその直後の吸気行程までの待ち
時間の相違に伴う空燃比のばらつき（一回一回、気筒
毎）を改良することができ、失火やトルク落ちのない良
好な運転性と排気性能が得られる。(Effects of the Invention) As described above, according to the present invention, when it is determined to perform asynchronous injection, a value that becomes smaller as the cycle position at that time becomes farther from the next intake stroke is set as the correction rate of the asynchronous injection amount. As a configuration in which at least a change in the intake negative pressure in the cylinder at the time when it is determined to perform the asynchronous injection does not overlap with the intake stroke is calculated for each cylinder and the asynchronous injection amount is corrected by the calculated correction rate. Therefore, at least for cylinders where the change in the intake negative pressure in the cylinder at the time when it is determined to perform asynchronous injection does not overlap with the intake stroke, the air-fuel ratio of the air-fuel ratio due to the difference in the waiting time from asynchronous injection to the intake stroke immediately after that The variation (once for each cylinder) can be improved, and good operability and exhaust performance without misfire or torque drop can be obtained.
第１図は本発明のクレーム対応図、第２図は本発明の一
実施例の制御系のシステム図、第３図はこの実施例と第
２実施例の演算内容をまとめて示す流れ図、第４図と第
５図はこの演算に使用される変数（GZTWとGZCYLn）の特
性線図、第６図は噴射時期に対する直接率Ｚの特性例、
第７図は急加速時における気筒別のポート部流速を示す
波形図、第８図は第２実施例のブロック構成図である。
第９図と第10図は第３実施例の流れ図、第11図と第13図
はそれぞれ緩加速時と急加速時における従来例の空燃比
誤差の変化波形図、第12図は緩加速時における第１実施
例の空燃比の変化波形図、第14図ないし第16図はそれぞ
れ急加速時における第１ないし第３実施例の空燃比の変
化波形図である。 １……非同期噴射判定手段、２……非同期噴射量演算手
段、３……気筒別補正率演算手段、４……補正手段、５
……駆動手段、10……燃料噴射弁、11……吸気ポート、
12……吸気絞り弁、14……絞り弁開度センサ、15……ク
ランク角センサ、16……水温センサ、17……空燃比セン
サ、18……コントロールユニット、51……急加速用補正
率演算手段、52……緩加速用補正率演算手段、53……切
換手段。FIG. 1 is a diagram corresponding to the claims of the present invention, FIG. 2 is a system diagram of a control system according to an embodiment of the present invention, and FIG. 3 is a flow chart collectively showing the arithmetic contents of this embodiment and the second embodiment. 4 and 5 are characteristic diagrams of variables (GZTW and GZCYLn) used in this calculation, and FIG. 6 is a characteristic example of the direct ratio Z with respect to the injection timing,
FIG. 7 is a waveform diagram showing the port flow velocity for each cylinder at the time of sudden acceleration, and FIG. 8 is a block diagram of the second embodiment.
9 and 10 are flow charts of the third embodiment, FIGS. 11 and 13 are waveform diagrams of changes in the air-fuel ratio error of the conventional example at the time of gentle acceleration and sudden acceleration, respectively, and FIG. 12 is at the time of gentle acceleration. FIG. 14 is a change waveform diagram of the air-fuel ratio of the first embodiment, and FIGS. 14 to 16 are change waveform diagrams of the air-fuel ratio of the first to third examples at the time of rapid acceleration. 1 ... Asynchronous injection determination means, 2 ... Asynchronous injection amount calculation means, 3 ... Cylinder correction factor calculation means, 4 ... Correction means, 5
...... Drive means, 10 …… Fuel injection valve, 11 …… Intake port,
12 …… Intake throttle valve, 14 …… Throttle valve opening sensor, 15 …… Crank angle sensor, 16 …… Water temperature sensor, 17 …… Air-fuel ratio sensor, 18 …… Control unit, 51 …… Rapid acceleration correction factor Computational means, 52 ... Slow acceleration correction factor computing means, 53 ... Switching means.
Claims (1)
同期噴射とは別に非同期噴射を行うかどうかを判定する
手段と、非同期噴射を行うことが判定されたときに前記
運転条件信号の変化量に基づいて気筒別に非同期噴射量
を演算する手段と、同じく非同期噴射を行うことが判定
されたときにその時点のサイクル位置が次の吸気行程か
ら遠いほど小さくなる値を前記非同期噴射量の補正率と
して、少なくとも非同期噴射を行うことが判定された時
点でのシリンダ内吸入負圧の変化が吸気行程と重ならな
い気筒について気筒別に演算する手段と、この演算され
た補正率にて前記非同期噴射量を補正する手段と、この
補正された非同期噴射量に応じた駆動信号にて気筒別に
燃料噴射弁を駆動する手段とを設けたことを特徴とする
内燃機関の空気量制御装置。1. A means for determining whether to perform an asynchronous injection separately from the synchronous injection for each rotation based on the amount of change of the operating condition signal, and the operation condition signal of the operation condition signal when it is determined to perform the asynchronous injection. A means for calculating the asynchronous injection amount for each cylinder based on the change amount, and a value that becomes smaller as the cycle position at that time becomes farther from the next intake stroke when it is determined that the asynchronous injection is to be performed. As a correction rate, a means for calculating for each cylinder a cylinder in which the change in the intake negative pressure in the cylinder does not overlap with the intake stroke at least when it is determined to perform the asynchronous injection, and the asynchronous injection with the calculated correction rate An amount of air for an internal combustion engine, characterized in that means for correcting the amount and means for driving a fuel injection valve for each cylinder by a drive signal according to the corrected asynchronous injection amount are provided. Control device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15612187A JPH0733783B2 (en) | 1987-06-23 | 1987-06-23 | Air-fuel ratio controller for internal combustion engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15612187A JPH0733783B2 (en) | 1987-06-23 | 1987-06-23 | Air-fuel ratio controller for internal combustion engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS643245A JPS643245A (en) | 1989-01-09 |
| JPH0733783B2 true JPH0733783B2 (en) | 1995-04-12 |
Family
ID=15620778
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15612187A Expired - Fee Related JPH0733783B2 (en) | 1987-06-23 | 1987-06-23 | Air-fuel ratio controller for internal combustion engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0733783B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01208540A (en) * | 1988-02-13 | 1989-08-22 | Mazda Motor Corp | Device for feeding fuel of engine |
| US4922877A (en) * | 1988-06-03 | 1990-05-08 | Nissan Motor Company, Limited | System and method for controlling fuel injection quantity for internal combustion engine |
| WO1990008252A1 (en) * | 1989-01-20 | 1990-07-26 | Mitsubishi Jidosha Kogyo Kabushiki Kaisha | Fuel control method at the time of acceleration of electronic control fuel injection engine |
| JPH03100345A (en) * | 1989-09-11 | 1991-04-25 | Honda Motor Co Ltd | Fuel supply controller of internal combustion engine |
| JP2611473B2 (en) * | 1990-02-02 | 1997-05-21 | トヨタ自動車株式会社 | Fuel injection amount control device for internal combustion engine |
| US6363313B1 (en) | 1999-04-06 | 2002-03-26 | Nissan Motor Co., Ltd. | Fuel property detecting system |
-
1987
- 1987-06-23 JP JP15612187A patent/JPH0733783B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS643245A (en) | 1989-01-09 |
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