JPH0886237A - Controller of internal combustion engine - Google Patents
Controller of internal combustion engineInfo
- Publication number
- JPH0886237A JPH0886237A JP22290694A JP22290694A JPH0886237A JP H0886237 A JPH0886237 A JP H0886237A JP 22290694 A JP22290694 A JP 22290694A JP 22290694 A JP22290694 A JP 22290694A JP H0886237 A JPH0886237 A JP H0886237A
- Authority
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- Prior art keywords
- stability
- fuel
- correction coefficient
- engine
- margin
- 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.)
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- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、例えば自動車用内燃機
関の燃料噴射量を制御するのに用いて好適な内燃機関の
制御装置に関し、特に、機関の冷却水温が低い場合に燃
料増量制御を行う内燃機関の制御装置の改良に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine, which is suitable for controlling the fuel injection amount of an internal combustion engine for an automobile, for example, and more particularly to a fuel increase control when the cooling water temperature of the engine is low. The present invention relates to improvement of a control device for an internal combustion engine.
【０００２】[0002]
【従来の技術】図９〜図１４に基づいて従来技術による
内燃機関の制御装置を説明する。一般に、自動車用内燃
機関では、運転条件に応じて燃料噴射弁からの燃料噴射
量を制御し、燃費の向上やエミッションの低減等を図る
べく、下記数１に従って燃料噴射量（噴射時間または噴
射パルス）を設定している。2. Description of the Related Art A conventional control apparatus for an internal combustion engine will be described with reference to FIGS. Generally, in an internal combustion engine for an automobile, the fuel injection amount from the fuel injection valve is controlled according to operating conditions, and the fuel injection amount (injection time or injection pulse is calculated according to the following equation 1 in order to improve fuel efficiency and reduce emissions. ) Is set.
【０００３】[0003]
【数１】Ｔi＝ＴP×(α＋αm)×(ＫAS＋ＫTW＋ＫHOT＋
ＭＲＫNK＋ＫMR)＋ＴS 但し、 Ｔi：通常の燃料噴射量 ＴP：基本噴射量 α：空燃比フィードバック補正係数 αm：空燃比補正学習値 ＫAS：始動後増量補正係数 ＫTW：水温増量補正係数 ＫHOT：高水温増量補正係数 ＭＲＫNK：ノック制御リタード時増量補正係数 ＫMR：混合比割付補正係数 ＴS：電圧補正 ここで、上記数１中に示す基本噴射量ＴPは、エアフロ
ーメータが検出した吸入空気量Ｑとクランク角センサが
検出した機関回転数Ｎとによって定まる噴射量の基本的
な値（ＴP＝Ｑ／Ｎ）である。また、空燃比フィードバ
ック補正係数αは、排気中の空燃比を理論空燃比近傍に
近づけて排気管の途中に設けられた触媒コンバータの転
化性能を高めるためのものであり、空燃比補正学習値α
mは、機関の運転条件が加減速時等の過渡域や高負荷域
等に入った場合でも、速やかに空燃比を理論空燃比近傍
に修正するためのものである。[Equation 1] T i = T P × (α + α m ) × (K AS + K TW + K HOT +
MRK NK + K MR ) + T S However, T i : Normal fuel injection amount T P : Basic injection amount α: Air-fuel ratio feedback correction coefficient α m : Air-fuel ratio correction learning value K AS : Start-up increase correction coefficient K TW : Water temperature Increase correction coefficient K HOT : High water temperature increase correction coefficient MRK NK : Knock control retard increase correction coefficient K MR : Mix ratio allocation correction coefficient T S : Voltage correction Here, the basic injection amount T P shown in the above equation 1 is It is a basic value (T P = Q / N) of the injection amount determined by the intake air amount Q detected by the air flow meter and the engine speed N detected by the crank angle sensor. The air-fuel ratio feedback correction coefficient α is used to bring the air-fuel ratio in the exhaust closer to the theoretical air-fuel ratio and improve the conversion performance of the catalytic converter provided in the middle of the exhaust pipe.
m is for promptly correcting the air-fuel ratio to near the stoichiometric air-fuel ratio even when the operating conditions of the engine enter a transient region such as acceleration / deceleration or a high load region.
【０００４】さらに、始動後増量補正係数ＫASは、図９
に示す如く、機関の冷却水温に応じて値が定まるもの
で、水温が低いほど値（初期値）が大きくなるように設
定され、所定回転数（例えば５回転）毎に値が段階的に
減少するようになっている。また、水温増量補正係数Ｋ
TWも、図１０に示す如く、機関の冷却水温に応じて値が
定まるもので、水温が低いほど初期値が大きくなるよう
に設定されている。Further, the increase correction coefficient K AS after starting is shown in FIG.
As shown in, the value is determined according to the cooling water temperature of the engine. The lower the water temperature, the larger the value (initial value) is set, and the value decreases stepwise every predetermined number of revolutions (for example, 5 revolutions). It is supposed to do. Also, the water temperature increase correction coefficient K
As shown in FIG. 10, the value of TW is also determined according to the cooling water temperature of the engine, and is set such that the lower the water temperature, the larger the initial value.
【０００５】一方、高水温増量補正係数ＫHOTは、図１
１に示す如く、冷却水温に応じて値が定まるもので、冷
却水温が所定の通常水温値ＴNWを上回ると、冷却水温が
大きくなるほど大きくなるように設定されている。ま
た、ノック制御リタード時増量補正係数ＭＲＫNKは、図
１２に示す如く、点火時期の補正値であるノック制御リ
タード量に応じて値が定まるもので、ノック制御リター
ド量が大きくなるほど大きくなるように設定されてい
る。On the other hand, the high water temperature increase correction coefficient K HOT is shown in FIG.
As shown in 1, the value is determined according to the cooling water temperature. When the cooling water temperature exceeds a predetermined normal water temperature value T NW , the cooling water temperature is set to increase as the cooling water temperature increases. Further, as shown in FIG. 12, the knock control retard increase correction coefficient MRK NK is determined according to the knock control retard amount which is the correction value of the ignition timing, and becomes larger as the knock control retard amount increases. It is set.
【０００６】混合比割付補正係数ＫMRは、図１３に示す
如く、機関回転数と基本噴射量ＴPに応じて予め割り付
けられたもので、高負荷、高回転になるほど値が大きく
なるように設定されており、最後に、電圧補正ＴSは、
図１４に示す如く、バッテリ電圧に応じて値が定まるも
ので、バッテリ電圧が低いほど値が大きくなるように設
定されている。As shown in FIG. 13, the mixing ratio allocation correction coefficient K MR is pre-allocated according to the engine speed and the basic injection amount T P, and the value increases as the load increases and the engine speed increases. Has been set, and finally, the voltage correction T S is
As shown in FIG. 14, the value is determined according to the battery voltage, and the lower the battery voltage, the larger the value.
【０００７】このように、従来技術では、基本噴射量Ｔ
Pの値に冷却水温等の機関の運転条件で定まる種々の修
正を加えて燃料噴射弁へ印加する噴射パルスの時間幅を
決定し、冷間始動時には、前記補正係数ＫASとＫTWとに
よって燃料噴射量を増量することにより、始動性や燃費
等の改善を図っている。ここで、「冷間始動時」とは、
機関の冷却水温が低い状態で機関を始動することをい
い、始動直後の状態を含むものである。As described above, in the prior art, the basic injection amount T
The time width of the injection pulse applied to the fuel injection valve is determined by adding various corrections to the value of P determined by the operating conditions of the engine such as the cooling water temperature, and at the time of cold start, the correction factors K AS and K TW are used. By increasing the fuel injection amount, the startability and fuel efficiency are improved. Here, "at the time of cold start" means
It means starting the engine in a state where the cooling water temperature of the engine is low, and includes the state immediately after the start.
【０００８】ところで、燃料には、その蒸発点の違いに
よって、気化しにくい重質燃料と、気化し易い軽質燃料
と、両者の中間に位置する標準燃料とがあり、これらの
燃料性状（重質、軽質、標準）によっても冷間始動時の
混合気濃度が変化するため、燃料性状を考慮せずに燃料
噴射量を増量制御しても、機関の運転条件に適合しない
おそれがある。即ち、冷間始動時に同量だけ燃料噴射量
を増量しても、重質燃料は気化しにくいから、壁流（吸
気通路の内面に付着した燃料の膜流）の分だけ混合気濃
度が低下して一時的にリーン状態となり、始動性が悪化
しうる。一方、軽質燃料を用いた場合は、機関温度が低
くても比較的速やかに気化するため、重質燃料と同じだ
け増量すると、リッチ状態となり、燃費やエミッション
性能が低下する可能性がある。By the way, there are two types of fuels: heavy fuels that are difficult to vaporize, light fuels that easily vaporize, and standard fuels located in between, depending on the difference in their evaporation points. , Light, standard), the air-fuel mixture concentration at cold start also changes, so even if the fuel injection amount is controlled to increase without considering the fuel properties, it may not meet the operating conditions of the engine. That is, even if the fuel injection amount is increased by the same amount during cold start, the heavy fuel is difficult to vaporize, so the mixture concentration decreases by the wall flow (the film flow of the fuel adhering to the inner surface of the intake passage). Then, the vehicle temporarily becomes lean and the startability may be deteriorated. On the other hand, when a light fuel is used, it vaporizes relatively quickly even if the engine temperature is low. Therefore, if the amount is increased by the same amount as that of the heavy fuel, a rich state may occur and fuel consumption and emission performance may decrease.
【０００９】そこで、かかる欠点を解消すべく、第２の
従来技術として、例えば特開平３−２６８４１号公報に
開示されたものでは、燃料の揮発性の相違によって始動
直後に生じるピーク回転の回転数と発生時間とが異なる
ことに着目し、このピーク回転が生じるまでの時間と、
その時のピーク回転数の値とによって燃料性状を判定
し、この判定された燃料性状に応じて増量補正係数の値
を設定することにより、増量制御（燃料増量の減量制
御）を行っている。Therefore, in order to eliminate such a drawback, as a second prior art, for example, in the one disclosed in Japanese Patent Laid-Open No. 3-26841, the rotational speed of the peak rotation which occurs immediately after the start due to the difference in the volatility of the fuel. Paying attention to the difference between the occurrence time and the occurrence time, the time until this peak rotation occurs,
The fuel property is determined based on the value of the peak rotational speed at that time, and the increase control (fuel increase / decrease control) is performed by setting the value of the increase correction coefficient according to the determined fuel property.
【００１０】また、第３の従来技術として、例えば特開
平３−６１６４４号公報に開示されたものでは、始動時
の回転数が冷却水温と燃料性状とによって略定まること
に着目し、冷却水温毎に設定された目標回転数と当該冷
却水温における実際の回転数との差分から燃料の性状を
判定し、この判定された燃料性状に応じて増量制御を行
っている。Further, as a third conventional technique, for example, in the one disclosed in Japanese Patent Laid-Open No. 3-61644, attention is paid to the fact that the number of revolutions at the time of starting is substantially determined by the cooling water temperature and the fuel property. The property of the fuel is determined from the difference between the target rotational speed set in step 1 and the actual rotational speed at the cooling water temperature, and the increase control is performed according to the determined fuel property.
【００１１】[0011]
【発明が解決しようとする課題】しかしながら、上述し
た第２の従来技術では、始動時のピーク回転の回転数と
発生時間とから燃料性状を判別し、燃料性状に応じて増
量制御を行っているものの、始動時回転数は、燃料性状
だけで定まるものではなく、バッテリ電圧、スタータモ
ータ性能、オイルの種類、点火性能等の種々の要因の影
響を受けるため、始動時回転数のパターン検出のみで燃
料性状を正確に判別するのは難しく、適切な増量制御を
行えない可能性がある。However, in the above-mentioned second conventional technique, the fuel property is determined from the number of revolutions and the time of occurrence of the peak rotation at the time of starting, and the increase control is performed according to the fuel property. However, the starting speed is not determined only by the fuel property, but is affected by various factors such as battery voltage, starter motor performance, oil type, ignition performance, etc., so it is only possible to detect the starting speed pattern. It is difficult to accurately determine the fuel property, and it may not be possible to perform appropriate increase control.
【００１２】また、第３の従来技術では、予め設定され
た目標回転数と実際の回転数との差分によって燃料性状
を判別し、増量制御を行っているものの、燃料性状を検
出するまでにある程度の時間を必要とするため、増量制
御に時間遅れが生じ易く、燃料性状に応じた空燃比を得
るのが難しい。Further, in the third conventional technique, although the fuel property is discriminated by the difference between the preset target speed and the actual speed and the increase control is performed, the fuel property is detected to some extent before the fuel property is detected. Therefore, it is difficult to obtain the air-fuel ratio according to the fuel property because the time delay is likely to occur in the increase control.
【００１３】本発明はかかる従来技術の問題に鑑みてな
されたもので、その目的は、燃料性状を正確に判別し、
この燃料性状に応じて冷間始動時の燃料噴射量を最適制
御できるようにした内燃機関の制御装置の提供にある。
また、本発明の他の目的は、重質燃料を用いたときの始
動性や運転性を高めつつ、軽質燃料を用いたときでも燃
費を向上してエミッション排出量を低減することができ
る内燃機関の制御装置を提供することにある。The present invention has been made in view of the above problems of the prior art, and its purpose is to accurately determine the fuel property,
It is an object of the present invention to provide a control device for an internal combustion engine that can optimally control the fuel injection amount at the time of cold start according to the fuel property.
Another object of the present invention is to improve the startability and drivability when using a heavy fuel, and to improve the fuel efficiency and reduce the emission amount when using a light fuel. It is to provide the control device.
【００１４】[0014]
【課題を解決するための手段】そこで、本発明に係る内
燃機関の制御装置は、機関の回転数を検出する回転数検
出手段と、この回転数に基づいて機関の安定状態を示す
安定性指標を演算する安定性指標演算手段と、この安定
性指標と予め設定された安定性許容レベルとを比較し、
両者の差分を安定性余裕代として演算する安定性余裕代
演算手段と、この安定性余裕代に基づいて燃料性状を検
出する燃料性状検出手段と、を備えたことを特徴として
いる。Therefore, a control device for an internal combustion engine according to the present invention includes a rotation speed detecting means for detecting the rotation speed of the engine, and a stability index indicating a stable state of the engine based on the rotation speed. Comparing the stability index calculation means for calculating and the stability index with a preset stability tolerance level,
It is characterized in that a stability margin margin calculating means for calculating a difference between the two as a stability margin margin and a fuel property detecting means for detecting a fuel property based on the stability margin margin are provided.
【００１５】また、請求項２に係る発明では、機関の回
転数を検出する回転数検出手段と、この回転数に基づい
て機関の安定状態を示す安定性指標を演算する安定性指
標演算手段と、この安定性指標と予め設定された安定性
許容レベルとを比較し、両者の差分を安定性余裕代とし
て演算する安定性余裕代演算手段と、この安定性余裕代
のうち機関始動後から現在までの間で最大値をとる最大
安定性余裕代と所定の基準値とを比較し、最大安定性余
裕代が所定の基準値以上のときには軽質燃料であると判
定し、最大安定性余裕代が所定の基準値未満のときには
重質燃料であると判定する燃料性状検出手段と、を備え
たことを特徴としている。Further, in the invention according to claim 2, there are provided a rotation speed detecting means for detecting the rotation speed of the engine, and a stability index calculating means for calculating a stability index indicating a stable state of the engine based on the rotation speed. , The stability index is compared with a preset stability tolerance level, and the difference between the two is calculated as the stability margin allowance, and the stability margin allowance calculation means, and the stability allowance allowance calculation means after the engine is started. Between the maximum stability margin allowance that takes the maximum value up to and the predetermined reference value, and when the maximum stability margin allowance is equal to or greater than the predetermined reference value, it is determined to be light fuel, and the maximum stability margin allowance is And a fuel property detection unit that determines that the fuel is a heavy fuel when it is less than a predetermined reference value.
【００１６】さらに、請求項３に係る発明では、機関の
回転数を検出する回転数検出手段と、この回転数に基づ
いて機関の安定状態を示す安定性指標を演算する安定性
指標演算手段と、この安定性指標と予め設定された安定
性許容レベルとを比較し、両者の差分を安定性余裕代と
して演算する安定性余裕代演算手段と、予め設定された
低水温時の燃料増量補正係数の値を補正するための安定
性補正係数を前記安定性余裕代に基づいて演算する安定
性補正係数演算手段と、この安定性補正係数と前記低水
温時の燃料増量補正係数と機関の運転条件に応じて定ま
る基本燃料噴射量とに基づいて燃料噴射量を演算する燃
料噴射量演算手段と、を備えたことを特徴としている。Further, in the invention according to claim 3, there are provided a rotation speed detection means for detecting the rotation speed of the engine, and a stability index calculation means for calculating a stability index indicating a stable state of the engine based on the rotation speed. , A stability margin calculation means for comparing the stability index with a preset stability tolerance level, and calculating a difference between the two as a stability margin, and a fuel increase correction coefficient at a preset low water temperature. Stability correction coefficient calculating means for calculating the stability correction coefficient based on the stability margin, the stability correction coefficient, the fuel increase correction coefficient at the low water temperature, and the engine operating condition. And a fuel injection amount calculation means for calculating the fuel injection amount based on the basic fuel injection amount determined in accordance with the above.
【００１７】また、前記安定性補正係数演算手段は、前
記安定性余裕代が所定の基準値以上のときには機関始動
後から現在までの間で最大値をとる最大安定性余裕代に
基づいて安定性補正係数を演算し、前記安定性余裕代が
前記所定の基準値未満のときには前記最大安定性余裕代
と現在の安定性余裕代との差分に基づいて安定性補正係
数を演算する構成とするのが好ましい。Further, the stability correction coefficient computing means is based on the maximum stability margin allowance which takes a maximum value after the engine is started until the present when the stability margin allowance is equal to or larger than a predetermined reference value. A correction coefficient is calculated, and when the stability margin is less than the predetermined reference value, the stability correction coefficient is calculated based on the difference between the maximum stability margin and the current stability margin. Is preferred.
【００１８】さらに、前記低水温時の燃料増量補正係数
を重質燃料に応じて設定し、前記安定性補正係数演算手
段は、０から前記低水温時の燃料増量補正係数の値まで
の範囲内で安定性補正係数を演算する構成とするのが望
ましい。Further, the fuel increase correction coefficient at the low water temperature is set according to the heavy fuel, and the stability correction coefficient calculating means is within a range from 0 to the value of the fuel increase correction coefficient at the low water temperature. It is desirable that the stability correction coefficient is calculated by
【００１９】本発明に係る内燃機関の制御装置のより具
体的な構成は、重質燃料に応じて予め設定された低水温
時の燃料増量補正係数により、機関が冷間始動したとき
に燃料噴射量の増量制御を行う内燃機関の制御装置であ
って、機関の回転数を検出する回転数検出手段と、この
回転数に基づいて機関の回転変動を検出し、この回転変
動に基づいて機関の安定状態を示す安定性指標を演算す
る安定性指標演算手段と、この安定性指標と予め機関の
運転条件毎に設定された安定性許容レベルとを比較し、
両者の差分を安定性余裕代として演算する安定性余裕代
演算手段と、前記低水温時の燃料増量補正係数の値を補
正すべく０から該低水温時の燃料増量補正係数の値まで
の範囲内で可変である安定性補正係数を、前記安定性余
裕代が所定の基準値以上のときには機関始動後から現在
までの間で最大値をとる最大安定性余裕代に基づいて演
算すると共に前記安定性余裕代が所定の基準値未満の場
合のときには前記最大安定性余裕代と現在の安定性余裕
代との差分に基づいて演算する安定性補正係数演算手段
と、この安定性補正係数と前記低水温時の燃料増量補正
係数と機関の運転条件に応じて定まる基本燃料噴射量と
に基づき、前記安定性補正係数の値が大きくなるにつれ
て燃料噴射量の値が小さくなるように燃料噴射量を演算
する燃料噴射量演算手段とを備えている。A more specific configuration of the control apparatus for an internal combustion engine according to the present invention is a fuel injection correction coefficient when a cold start of the engine is performed by a fuel increase correction coefficient at a low water temperature preset according to heavy fuel. A control device for an internal combustion engine that performs an increase control of the amount, wherein a rotation speed detection means for detecting the rotation speed of the engine and a rotation fluctuation of the engine based on this rotation speed are detected, and based on this rotation fluctuation, A stability index calculating means for calculating a stability index indicating a stable state, and comparing the stability index with a stability tolerance level set in advance for each operating condition of the engine,
Stability margin calculation means for calculating the difference between the two as a stability margin, and a range from 0 to the value of the fuel increase correction coefficient at the low water temperature in order to correct the value of the fuel increase correction coefficient at the low water temperature. The stability correction coefficient, which is variable within the stability margin, is calculated based on the maximum stability margin, which takes a maximum value from the engine start to the present when the stability margin is equal to or greater than a predetermined reference value. When the margin allowance is less than a predetermined reference value, a stability correction coefficient computing means for computing based on the difference between the maximum stability margin and the current stability margin, and the stability correction coefficient and the low margin are calculated. The fuel injection amount is calculated so that the value of the fuel injection amount decreases as the value of the stability correction coefficient increases, based on the fuel increase correction coefficient at the water temperature and the basic fuel injection amount determined according to the operating conditions of the engine. Fuel injection amount And a means.
【００２０】また、前記安定性指標演算手段は、前記回
転数検出手段が機関の各気筒の点火に応じて出力する回
転数信号間の時間を求め、この点火に応じた回転数信号
間の時間の変動を気筒別変化量として各気筒毎に演算す
る手段と、この気筒別変化量を隣接する気筒間で比較し
て周期変動を演算する手段と、この周期変動を所定サイ
クルだけ積算することにより安定性指標を演算する手段
と、から構成するのが望ましい。Further, the stability index computing means obtains the time between the rotation speed signals output by the rotation speed detection means according to the ignition of each cylinder of the engine, and the time between the rotation speed signals according to the ignition. By calculating the fluctuation of each cylinder as a cylinder-by-cylinder change amount for each cylinder, by comparing the cylinder-by-cylinder change amount between adjacent cylinders and calculating a cycle fluctuation, and by integrating the cycle fluctuation for a predetermined cycle, It is desirable to be composed of a means for calculating a stability index.
【００２１】[0021]
【作用】燃料噴射量が適切でなければ、機関に回転変動
が生じて不安定になるため、回転数検出手段が検出した
機関の回転数に基づいて、現在の機関の安定状態を示す
安定性指標を得ることができる。そして、この安定性指
標と予め設定された安定性許容レベルとを比較して得ら
れる両者の差分は、機関の状態が安定性の限界からどの
程度離れているかを示す安定性余裕代となる。ここで、
燃料には、気化しにくい重質燃料と気化し易い軽質燃料
とがあるが、冷間始動時には機関の温度が低いため、重
質燃料を用いた場合は、壁流の影響を受けて混合気の濃
度が低下し、リーン気味となって始動直後の回転が不安
定になり易い。一方、軽質燃料を用いた場合は、気化し
易いため、始動直後の回転は安定する。従って、重質燃
料の場合は、安定性指標が悪化して安定性許容レベルに
近づくため、安定性余裕代が小さくなる。これに対し、
軽質燃料の場合は、安定性指標が向上して安定性許容レ
ベルから離れるため、安定性余裕代が大きくなる。これ
により、安定性余裕代に基づいて燃料性状を判別するこ
とができ、この判別された燃料性状に応じて燃料噴射量
を制御することができる。If the fuel injection amount is not appropriate, the engine will be unstable due to fluctuations in the engine speed. Therefore, the stability indicating the present stable state of the engine based on the engine speed detected by the engine speed detecting means. You can get an index. Then, the difference between the stability index and the preset allowable stability level, which is a difference between the two, serves as a margin for stability indicating how far the engine state is from the stability limit. here,
There are two types of fuel, heavy fuel that is difficult to vaporize and light fuel that is easily vaporized.However, since the temperature of the engine is low at cold start, when heavy fuel is used, it will be affected by the wall flow and the mixture will be mixed. Density decreases, and it tends to become lean, and the rotation immediately after starting becomes unstable. On the other hand, when a light fuel is used, it is easily vaporized, so that the rotation immediately after the start is stable. Therefore, in the case of heavy fuel, the stability index deteriorates and approaches the stability allowable level, so the stability margin is reduced. In contrast,
In the case of light fuel, the stability index is improved and deviates from the stability allowable level, so the stability margin is increased. As a result, the fuel property can be determined based on the stability margin, and the fuel injection amount can be controlled according to the determined fuel property.
【００２２】また、燃料噴射量の制御に応じて安定性余
裕代は変化するが、最大値をとる最大安定性余裕代は、
燃料性状に起因する燃料の応答性（揮発性）及び吸入空
気との混合状態によって定まる。そこで、この最大安定
性余裕代と所定の基準値とを比較することにより、軽質
燃料であるか重質燃料であるかを判定することができ
る。Further, although the stability margin margin changes depending on the control of the fuel injection amount, the maximum stability margin margin having the maximum value is
It is determined by the responsiveness (volatility) of the fuel due to the fuel property and the mixed state with the intake air. Therefore, it is possible to determine whether the fuel is a light fuel or a heavy fuel by comparing this maximum stability margin with a predetermined reference value.
【００２３】さらに、請求項３の構成によれば、燃料性
状を反映した安定性余裕代に基づいて、低水温時の燃料
増量補正係数を補正するための安定性補正係数を演算
し、この安定性補正係数と低水温時の燃料増量補正係数
と機関の運転条件に応じて定まる基本噴射量とに基づい
て燃料噴射量を演算することにより、冷間始動時の燃料
噴射量を燃料性状に応じて制御することができる。Further, according to the third aspect of the invention, the stability correction coefficient for correcting the fuel increase correction coefficient at low water temperature is calculated based on the stability margin margin reflecting the fuel property, and this stability is calculated. The fuel injection amount at cold start is calculated according to the fuel property by calculating the fuel injection amount based on the fuel injection correction coefficient, the fuel increase correction coefficient at low water temperature, and the basic injection amount determined according to the engine operating conditions. Can be controlled.
【００２４】また、安定性余裕代が所定の基準値以上の
ときは最大安定性余裕代に基づいて安定性補正係数を演
算し、安定性余裕代が所定の基準値未満のときは最大安
定性余裕代と現在の安定性余裕代との差分に基づいて安
定性補正係数を演算する構成とすれば、最大安定性余裕
代に反映されている燃料性状に応じて燃料噴射量を制御
しつつ、現在の安定性余裕代に反映されている機関の現
在の安定状態をフィードバックすることができる。When the stability margin is equal to or larger than a predetermined reference value, the stability correction coefficient is calculated based on the maximum stability margin, and when the stability margin is less than the predetermined reference value, the maximum stability is calculated. If the stability correction coefficient is calculated based on the difference between the allowance allowance and the current stability allowance allowance, while controlling the fuel injection amount according to the fuel property reflected in the maximum stability allowance allowance, The current stable state of the engine, which is reflected in the current stability margin, can be fed back.
【００２５】さらに、前記低水温時の燃料増量補正係数
を重質燃料に応じて設定し、前記安定性補正係数演算手
段は、０から前記低水温時の燃料増量補正係数の値まで
の範囲内で安定性補正係数を演算する構成とすれば、安
定性余裕代の小さい重質燃料の場合に、重質燃料に応じ
た燃料増量を行うことができると共に、軽質燃料の場合
には、重質燃料に応じて設定された燃料増量を減量する
ことができる。Further, the fuel increase correction coefficient at the low water temperature is set according to the heavy fuel, and the stability correction coefficient calculating means is within a range from 0 to the value of the fuel increase correction coefficient at the low water temperature. If the stability correction coefficient is calculated with, it is possible to increase the fuel amount according to the heavy fuel in the case of heavy fuel with a small margin of stability margin, and to add heavy fuel in the case of light fuel. It is possible to reduce the fuel increase amount set according to the fuel.
【００２６】また、より具体的な請求項６に係る構成に
よれば、上述した如く、燃料性状と機関の現在の安定状
態とに応じて安定補正係数を設定し、この安定性補正係
数をもって低水温時の燃料増量補正係数を補正すること
ができるため、安定性余裕代の小さい重質燃料の場合は
十分な燃料増量を行うことができると共に、安定性余裕
代の大きい軽質燃料の場合は燃料増量を少なくすること
ができ、冷間始動時に燃料性状に応じた燃料噴射量を得
ることができる。Further, according to the more specific configuration of claim 6, as described above, the stability correction coefficient is set in accordance with the fuel property and the current stable state of the engine, and the stability correction coefficient is set to a low value. Since the fuel increase correction coefficient at the water temperature can be corrected, sufficient fuel increase can be performed in the case of heavy fuel with a small margin of stability and fuel can be increased in the case of light fuel with a large margin of stability. It is possible to reduce the amount of increase, and it is possible to obtain the fuel injection amount according to the fuel property at the cold start.
【００２７】また、前記安定性指標演算手段は、前記回
転数検出手段が機関の各気筒の点火に応じて出力する回
転数信号間の時間を求め、この点火に応じた回転数信号
間の時間の変動を気筒別変化量として各気筒毎に演算す
る手段と、この気筒別変化量を隣接する気筒間で比較し
て周期変動を演算する手段と、この周期変動を所定サイ
クルだけ積算することにより安定性指標を演算する手段
とから構成すれば、各気筒の点火に応じて出力される回
転数信号間のバラツキに影響されずに、機関の安定状態
を知ることができる。Further, the stability index calculating means obtains the time between the rotation speed signals output by the rotation speed detecting means according to the ignition of each cylinder of the engine, and the time between the rotation speed signals according to the ignition. By calculating the fluctuation of each cylinder as a cylinder-by-cylinder change amount for each cylinder, by comparing the cylinder-by-cylinder change amount between adjacent cylinders and calculating a cycle fluctuation, and by integrating the cycle fluctuation for a predetermined cycle, The stability state of the engine can be known without being affected by the variation between the rotation speed signals output according to the ignition of each cylinder, if the stability index is calculated.
【００２８】[0028]
【実施例】以下、本発明の実施例を図１〜図８に基づい
て説明する。なお、実施例では、上述した従来技術で述
べた各種補正係数と同一の補正係数には同一の名称を付
し、その説明を省略するものとする。Embodiments of the present invention will be described below with reference to FIGS. It should be noted that, in the embodiment, the same names as the various correction coefficients described in the above-described related art are given the same names, and the description thereof will be omitted.
【００２９】まず、図１は、本発明の実施例に係る内燃
機関の制御装置の全体構成を示す構成説明図であって、
シリンダブロックに例えば４個設けられた気筒たるシリ
ンダ１（１個のみ図示）内にはピストン２が摺動可能に
設けられ、このピストン２のヘッド部とシリンダヘッド
との間には燃焼室３が画成されている。この燃焼室３に
は、吸気ポート４を介して吸気通路５が接続されると共
に、排気ポート６を介して排気通路７が接続されてい
る。吸気通路５は、その上流側が図示せぬエアフィルタ
に接続され、その下流側はコレクタ部５Ａから気筒数に
応じて分岐し、吸気ポート４を開閉する吸気弁８を介し
て燃焼室３に接続されている。排気通路７は、その上流
側が排気ポート６を開閉する排気弁９を介して燃焼室３
に接続され、その下流側は集合して図外のマフラに接続
されている。First, FIG. 1 is a structural explanatory view showing the overall structure of a control device for an internal combustion engine according to an embodiment of the present invention.
A piston 2 is slidably provided in a cylinder 1 (only one is shown), which is, for example, four cylinders provided in a cylinder block, and a combustion chamber 3 is provided between the head portion of the piston 2 and the cylinder head. Well defined. An intake passage 5 is connected to the combustion chamber 3 via an intake port 4, and an exhaust passage 7 is connected to the combustion chamber 3 via an exhaust port 6. The intake passage 5 has its upstream side connected to an air filter (not shown), and its downstream side branches from the collector section 5A according to the number of cylinders and is connected to the combustion chamber 3 via an intake valve 8 that opens and closes the intake port 4. Has been done. The exhaust passage 7 is connected to the combustion chamber 3 via an exhaust valve 9 whose upstream side opens and closes the exhaust port 6.
Is connected to the muffler (not shown).
【００３０】また、吸気通路５には、コレクタ部５Ａと
エアフィルタとの間に位置して吸入空気量を調整するた
めのスロットル弁１０が設けられ、このスロットル弁１
０とエアフィルタとの間には、吸入空気量を検出するた
めのエアフローメータ１１が設けられている。そして、
スロットル弁１０のスロットル開度を検出するスロット
ルセンサ１２とエアフローメータ１１とは、後述のコン
トロールユニット２４に接続されている。さらに、スロ
ットル弁１０をバイパスする補助空気通路１３の途中に
は、アイドルスピードコントロール弁（ＩＳＣ弁）１４
が設けられ、このＩＳＣ弁１４によって補助空気通路１
３を流れる空気量が調整される。Further, the intake passage 5 is provided with a throttle valve 10 located between the collector portion 5A and the air filter for adjusting the amount of intake air.
An air flow meter 11 for detecting the intake air amount is provided between 0 and the air filter. And
The throttle sensor 12 for detecting the throttle opening degree of the throttle valve 10 and the air flow meter 11 are connected to a control unit 24 described later. Further, an idle speed control valve (ISC valve) 14 is provided in the middle of the auxiliary air passage 13 that bypasses the throttle valve 10.
Is provided, and the auxiliary air passage 1 is provided by the ISC valve 14.
The amount of air flowing through 3 is adjusted.
【００３１】燃料噴射弁１５は、吸気ポート４を指向し
て吸気通路５の下流側に設けられ、コントロールユニッ
ト２４からの噴射信号（噴射パルス）によって開弁する
ことにより、噴射パルス幅に応じた量の燃料を吸気ポー
ト４に向けて噴射するようになっている。また、シリン
ダヘッドには、先端側が燃焼室３内に臨むようにして点
火栓１６が設けられており、この点火栓１６はイグニッ
ションコイル等を内蔵した図示せぬディストリビュータ
を介してコントロールユニット２４に接続されている。The fuel injection valve 15 is provided on the downstream side of the intake passage 5 toward the intake port 4 and opens according to the injection signal (injection pulse) from the control unit 24, so that the fuel injection valve 15 can respond to the injection pulse width. A certain amount of fuel is injected toward the intake port 4. Further, the cylinder head is provided with an ignition plug 16 with its tip end facing the inside of the combustion chamber 3, and this ignition plug 16 is connected to the control unit 24 via a distributor (not shown) having an ignition coil and the like built therein. There is.
【００３２】一方、排気通路７の途中には例えば３元触
媒等からなる触媒コンバータ１７が嵌装され、この触媒
コンバータ１７の上流側，下流側には、例えばジルコニ
ア管の内外面に白金電極をコーティングしてなる酸素セ
ンサ（空燃比センサ）１８，１９がそれぞれ設けられて
いる。この上流側酸素センサ１８は、触媒コンバータ１
７を通過する前の排気ガス中の酸素濃度を検出するもの
で、コントロールユニット２４は、酸素濃度に応じて周
期的に反転する上流側酸素センサ１８の検出信号を利用
することにより、空燃比フィードバック制御を行う。ま
た、下流側酸素センサ１９は、触媒コンバータ１７を通
過した後の排気ガス中の酸素濃度を検出するもので、そ
の検出信号は触媒コンバータ１７の酸素ストレージ能力
によって緩やかな変動を示す。従って、触媒コンバータ
１７が正常であれば両検出信号の反転周期は大きく異な
るが、触媒コンバータ１７が劣化すれば、上流側酸素セ
ンサ１８の検出信号の反転周期と下流側酸素センサ１９
の検出信号の反転周期との相違が小さくなるため、コン
トロールユニット２４は、両検出信号の反転周期を比較
することで、触媒コンバータ１７の劣化を検出するよう
になっている。On the other hand, a catalytic converter 17 made of, for example, a three-way catalyst is fitted in the middle of the exhaust passage 7. On the upstream and downstream sides of this catalytic converter 17, for example, platinum electrodes are provided on the inner and outer surfaces of a zirconia tube. Coated oxygen sensors (air-fuel ratio sensors) 18 and 19 are provided, respectively. The upstream oxygen sensor 18 is used in the catalytic converter 1
In order to detect the oxygen concentration in the exhaust gas before passing through the control unit 7, the control unit 24 uses the detection signal of the upstream oxygen sensor 18 that periodically inverts according to the oxygen concentration, thereby providing air-fuel ratio feedback. Take control. Further, the downstream oxygen sensor 19 detects the oxygen concentration in the exhaust gas after passing through the catalytic converter 17, and the detection signal shows a gradual change due to the oxygen storage capacity of the catalytic converter 17. Therefore, if the catalytic converter 17 is normal, the inversion cycle of both detection signals greatly differs, but if the catalytic converter 17 deteriorates, the inversion cycle of the detection signal of the upstream oxygen sensor 18 and the downstream oxygen sensor 19
Since the difference from the inversion cycle of the detection signal of 1 becomes small, the control unit 24 detects the deterioration of the catalytic converter 17 by comparing the inversion cycles of both detection signals.
【００３３】回転数検出手段としてのクランク角センサ
２０は、例えば電磁式ピックアップコイル等から構成さ
れており、機関の回転を１度、１８０度（６気筒の場合
は１２０度）毎に検出するものである。そして、このク
ランク角センサ２０は、車速を検出する車速センサ２１
と、イグニッションスイッチの状態を検出するスタート
スイッチ２２と、ウォータジャケットを流通する冷却水
温を検出する水温センサ２３と、ノッキングを検出する
ノックセンサ（図示せず）と共に、コントロールユニッ
ト２４に接続されている。The crank angle sensor 20 as the rotation speed detecting means is composed of, for example, an electromagnetic pickup coil, etc., and detects the rotation of the engine every 1 degree, 180 degrees (120 degrees in the case of 6 cylinders). Is. The crank angle sensor 20 is a vehicle speed sensor 21 that detects the vehicle speed.
A start switch 22 that detects the state of the ignition switch, a water temperature sensor 23 that detects the temperature of the cooling water flowing through the water jacket, and a knock sensor (not shown) that detects knocking are connected to the control unit 24. .
【００３４】ＣＰＵ等の演算処理回路、ＲＯＭ，ＲＡＭ
等の記憶回路、入出力回路（いずれも図示せず）等から
マイクロコンピュータシステムとして構成されたコント
ロールユニット２４は、機関を電気的に集中制御するも
のである。このコントロールユニット２４は、図２の機
能ブロック図に示す如く、クランク角センサ２０からの
ＲＥＦ信号に基づいて機関の安定状態を示す安定性指標
ＴＲＦＳＵＭを演算する安定性指標演算手段２４Ａと、
機関の運転条件毎に予め設定された安定性許容レベルＳ
ＴＢＳＬをマップを読み出して求める安定性許容レベル
演算手段２４Ｂと、安定性指標ＴＲＦＳＵＭと安定性許
容レベルＳＴＢＳＬとを比較し、両者の差分を安定性余
裕代ＳＴＢとして演算する安定性余裕代演算手段２４Ｃ
と、この安定性余裕代ＳＴＢに基づいて図５と共に後述
するマップを読み出すことにより、安定性補正率ＬＳＴ
Ｂを演算する安定性補正率演算手段２４Ｄと、この安定
性補正率ＬＳＴＢを予め重質燃料に応じて設定された低
水温時の各燃料増量補正係数（ＫAS＋ＫTW）に乗じるこ
とにより、安定性補正係数ＫSTBを求める安定性補正係
数演算手段２４Ｅと、数１と共に上述した各種補正係数
の総和（ＫAS＋ＫTW＋ＫHOT＋ＭＲＫNK＋ＫMR）から安
定性補正係数ＫSTBを差し引くことにより、目標空燃比
を設定するための空燃比設定補正係数ＴＦＢＹＡを演算
する空燃比設定補正係数演算手段２４Ｆと、この空燃比
設定補正係数ＴＦＢＹＡと機関の運転条件に応じて定ま
る基本燃料噴射量ＴPとに基づいて機関に設けられた燃
料噴射弁の噴射パルス幅（燃料噴射量）Ｔiを演算する
燃料噴射量演算手段２４Ｇと、を備えている。Arithmetic processing circuit such as CPU, ROM, RAM
A control unit 24 configured as a microcomputer system from a storage circuit such as the above, an input / output circuit (none of which is shown), and the like electrically centrally controls the engine. As shown in the functional block diagram of FIG. 2, the control unit 24 includes stability index calculation means 24A for calculating a stability index TRFSUM indicating a stable state of the engine based on the REF signal from the crank angle sensor 20,
Stability allowable level S preset for each engine operating condition
The stability allowance level calculating means 24C for comparing the stability index TRFSUM and the stability allowance level STBSL with each other and calculating the difference between the stability allowance level calculating means 24B for obtaining the TBSL by reading the map as the stability allowance allowance STB.
And a stability correction factor LST is obtained by reading a map described later with reference to FIG. 5 based on the stability margin STB.
By multiplying the stability correction factor calculation means 24D for calculating B and the stability correction factor LSTB by each fuel increase correction coefficient (K AS + K TW ) at low water temperature set in advance for heavy fuel, and stability correction coefficient calculating means 24E for determining the stability correction coefficient K STB, by subtracting the stability correction coefficient K STB from the sum of the above-described various correction coefficients with the number 1 (K aS + K TW + K HOT + MRK NK + K MR) , An air-fuel ratio setting correction coefficient calculation unit 24F for calculating an air-fuel ratio setting correction coefficient TFBYA for setting a target air-fuel ratio, and a basic fuel injection amount T P determined according to the air-fuel ratio setting correction coefficient TFBYA and the engine operating conditions. And a fuel injection amount calculation means 24G for calculating the injection pulse width (fuel injection amount) T i of the fuel injection valve provided in the engine based on the above.
【００３５】次に、図３〜図７に基づいて上述したコン
トロールユニット２４の各機能を詳述する。まず、図３
は安定性指標ＴＲＦＳＵＭを演算して求める安定性指標
演算手段の具体的なフローチャートを示し、ステップ１
では、クランク角センサ２０から各気筒毎に応じて出力
されるＲＥＦ信号を読込み、これら各ＲＥＦ信号間の時
間ＴＲＥＦをサンプリングする。ここで、ＲＥＦ信号と
は、各気筒での爆発に対応してクランク角センサ２０が
出力する信号であり、４気筒の場合は１８０度毎に、６
気筒の場合は１２０度毎にクランク角センサ２０から出
力される。即ち、このＲＥＦ信号間時間ＴＲＥＦとは、
ある気筒の点火から次の気筒の点火までの間の時間を示
すパラメータである。Next, each function of the control unit 24 described above will be described in detail with reference to FIGS. First, FIG.
Shows a specific flow chart of the stability index calculation means for calculating and calculating the stability index TRFSUM, step 1
Then, the REF signal output from the crank angle sensor 20 according to each cylinder is read, and the time TREF between these REF signals is sampled. Here, the REF signal is a signal output by the crank angle sensor 20 in response to an explosion in each cylinder, and in the case of four cylinders, it is 6 every 6 degrees.
In the case of a cylinder, it is output from the crank angle sensor 20 every 120 degrees. That is, the time TREF between REF signals is
It is a parameter indicating the time from the ignition of one cylinder to the ignition of the next cylinder.
【００３６】次に、ステップ２では、前記ステップ１で
サンプリングされたＲＥＦ信号間時間ＴＲＥＦの各気筒
別の変化量ＴＲＥＦＣを、下記数２により求める。Next, in step 2, the variation amount TREFC for each cylinder of the inter-REF signal time TREF sampled in step 1 is obtained by the following equation 2.
【００３７】[0037]
【数２】 ＴＲＥＦＣ(ｎ)＝ＴＲＥＦ(ｎ)−ＴＲＥＦ(ｎ−４) これにより、各気筒毎のＲＥＦ信号間の時間ＴＲＥＦの
変化が分かる。例えば仮に、４つの気筒ＣA，ＣB，
ＣC，ＣDがあり、ＣA→ＣB→ＣC→ＣD→ＣAの順序で点
火されるとすれば、ＣDが点火されてからＣAが点火され
るまでの時間ＴＲＥＦ（ｎ）と、次に再びＣDが点火さ
れてからＣAが点火されるまでの時間ＴＲＥＦ（ｎ−
４）との差分が、気筒ＣAにおける気筒別変化量ＴＲＥ
ＦＣとなる。以下同様にして、他の気筒ＣB，ＣC，ＣD
毎に、気筒別変化量ＴＲＥＦＣをそれぞれ求める。そし
て、ステップ３では、下記数３に従って、ステップ２で
求められた気筒別変化量ＴＲＥＦＣの値を隣接する気筒
間（点火順序における「隣接」）で比較し、ＲＥＦ周期
変動ＴＲＦＯＵＴを演算する。## EQU00002 ## TREFC (n) = TREF (n) -TREF (n-4) Thus, the change in the time TREF between the REF signals for each cylinder can be known. For example, if four cylinders C A , C B ,
If there are C C and C D and ignition is performed in the order of C A → C B → C C → C D → C A , the time TREF (from the ignition of C D to the ignition of C A ( and n), the time until the next C a from being ignited again C D is ignited TREF (n-
The difference between 4), cylinder variation in the cylinder C A TRE
It becomes FC. Similarly, the other cylinders C B , C C , C D
The cylinder-by-cylinder change amount TREFC is obtained for each. Then, in step 3, the value of the cylinder-by-cylinder variation amount TREFC obtained in step 2 is compared between adjacent cylinders (“adjacent” in the ignition order) and the REF cycle fluctuation TRFOUT is calculated according to the following expression 3.
【００３８】[0038]
【数３】ＴＲＦＯＵＴ(ｎ)＝ＴＲＥＦＣ(ｎ)−ＴＲＥＦ
Ｃ(ｎ−１) 即ち、気筒ＣAにおける気筒別変化量ＴＲＥＦＣ（ｎ）
と、次に点火される気筒ＣBにおける気筒別変化量ＴＲ
ＥＦＣ（ｎ−１）との差分がＲＥＦ周期変動ＴＲＦＯＵ
Ｔとなる。同様にして、気筒ＣBと気筒ＣCとの間、気筒
ＣCと気筒ＣDとの間、気筒ＣDと気筒ＣAとの間、におけ
る気筒別変化量ＴＲＥＦＣの差もそれぞれ演算される。
従って、この周期変動ＴＲＦＯＵＴは、各気筒のＲＥＦ
周期のバラツキを補正した値となる。即ち、上述した通
り、各気筒毎にＲＥＦ信号間の時間ＴＲＥＦの変動をＴ
ＲＥＦＣとして求め、このＲＥＦ信号の変化量ＴＲＥＦ
Ｃを隣接する気筒間で比較することにより、周期変動Ｔ
ＲＦＯＵＴを求めているため、機関固有のＲＥＦ信号の
バラツキによる影響を受けないばかりか、回転数が上昇
したり下降した場合にも各気筒間のＲＥＦ信号周期の変
動を容易かつ正確に求めることができる。[Formula 3] TRFOUT (n) = TREFC (n) -TREF
C (n-1) words, cylinder variation in the cylinder C A TREFC (n)
And the cylinder-by-cylinder variation amount TR in the cylinder C B to be ignited next
The difference from EFC (n-1) is REF cycle fluctuation TRFOU
It becomes T. Similarly, differences between the cylinder-by-cylinder variation amounts TREFC between the cylinders C B and C C , between the cylinders C C and C D, and between the cylinders C D and C A are also calculated. .
Therefore, this cycle fluctuation TRFOUT is the REF of each cylinder.
It is a value that corrects for variations in the cycle. That is, as described above, the fluctuation of the time TREF between the REF signals for each cylinder is T
The amount of change of this REF signal TREF
By comparing C between adjacent cylinders, the periodic fluctuation T
Since RFOUT is obtained, not only is it unaffected by variations in the REF signal peculiar to the engine, but it is also possible to easily and accurately obtain the variation in the REF signal cycle between cylinders even when the rotation speed increases or decreases. it can.
【００３９】最後に、ステップ４では、前記ステップ３
で求めた周期変動ＴＲＦＯＵＴの絶対値を所定サイクル
としてのＮＣサイクル分だけ積算することにより、機関
の安定状態（安定度）を示す安定性指標ＴＲＦＣＵＭを
算出する。このようにして演算された安定性指標ＴＲＦ
ＣＵＭは、各気筒の変動を統計処理した後の回転変動を
示すため、機関の回転の安定状態を示す指標として用い
ることができる。Finally, in step 4, step 3
The stability index TRFCUM indicating the stable state (stability) of the engine is calculated by accumulating the absolute value of the cycle fluctuation TRFOUT obtained in (3) for NC cycles as a predetermined cycle. Stability index TRF calculated in this way
Since the CUM shows the rotation fluctuation after statistically processing the fluctuation of each cylinder, it can be used as an index showing the stable state of the engine rotation.
【００４０】次に、図４のフローチャート及び図５のマ
ップに基づいて安定性補正率ＬＳＴＢ及び安定性補正係
数ＫSTBの演算処理内容を説明する。まず、ステップ１
１では、水温センサ２３が検出した冷却水温とスロット
ルセンサ１２のアイドル接点の状態とから燃料増量補正
の減量を行うべきファストアイドル状態（比較的回転数
の高いアイドリング状態）であるか否かを判定する。こ
のステップ１１で「ＹＥＳ」と判定したときは、機関が
ファストアイドル状態にある場合だから、次のステップ
１２では、予め設定された安定性の限界値を示す安定性
許容レベルＳＴＢＳＬと、図３のフローチャートで得ら
れた安定性指標ＴＲＦＳＵＭとの差分を求めることによ
り（ＳＴＢ＝ＳＴＢＳＬ−ＴＲＦＳＵＭ）、現時点にお
ける機関の安定性余裕代ＳＴＢを演算する。一方、前記
ステップ１１で「ＮＯ」と判定したときは、直前の安定
性余裕代ＳＴＢを保持する。Next, the contents of the process for calculating the stability correction factor LSTB and stability correction coefficient K STB is described based on a map of the flow chart and Figure 5 in FIG. First, step 1
At 1, it is determined from the cooling water temperature detected by the water temperature sensor 23 and the state of the idle contact of the throttle sensor 12 whether or not it is the fast idle state (the idling state where the rotational speed is relatively high) in which the amount of fuel increase correction should be reduced. To do. If "YES" is determined in this step 11, it means that the engine is in the fast idle state. Therefore, in the next step 12, the stability allowable level STBSL indicating the preset limit value of stability and the stability allowable level STBSL of FIG. By calculating the difference from the stability index TRFSUM obtained in the flowchart (STB = STBSL-TRFSUM), the stability margin allowance STB of the engine at the present time is calculated. On the other hand, if it is determined to be "NO" in step 11, the stability margin STB immediately before is held.
【００４１】ここで、この安定性許容レベルＳＴＢＳＬ
は、機関の回転数や負荷等の運転条件によって異なるた
め、予め実機試験により定められる。具体的には、実機
試験により、筒内圧変動率や回転変動率等をモニタして
機関の安定限界を検出し、この安定限界における安定性
指標ＴＲＦＳＵＭを求め、この安定限界上の安定性指標
ＴＲＦＳＵＭを安定性許容レベルＳＴＢＳＬとして、各
運転条件毎にマップ化し、コントロールユニット２４に
予め記憶させておくのである。Here, this stability allowable level STBSL
Is different depending on operating conditions such as the engine speed and load, and is determined in advance by an actual machine test. Specifically, the in-cylinder pressure fluctuation rate, the rotation fluctuation rate, etc. are monitored by an actual machine test to detect the stability limit of the engine, the stability index TRFSUM at this stability limit is determined, and the stability index TRFSUM on this stability limit is obtained. Is defined as a stability allowable level STBSL and is mapped for each operating condition and stored in the control unit 24 in advance.
【００４２】そして、ステップ１４では、前記ステップ
１２で求めた安定性余裕代ＳＴＢが所定の基準値として
の「０」以上か否かを判定する。このステップ１４で
「ＹＥＳ」と判定したときは、現在の運転条件において
機関の安定性に余裕がある場合のため、次のステップ１
５に移り、機関始動時から現時点までのファストアイド
ル期間中に得られた安定性余裕代ＳＴＢのうち、最大の
値をとる最大安定性余裕代ＳＴＢMAXに基づいて、図５
に示す補正率マップから安定側補正率ＬＳＢ1を読み出
す。Then, in step 14, it is determined whether or not the stability margin allowance STB obtained in step 12 is equal to or larger than "0" as a predetermined reference value. If "YES" is determined in this step 14, because there is a margin in stability of the engine under the current operating conditions, the following step 1
5, the maximum stability margin allowance STB MAX that takes the maximum value among the stability margin allowances STB obtained during the fast idle period from the engine start to the present time is calculated based on FIG.
The stable correction rate LSB 1 is read from the correction rate map shown in FIG.
【００４３】即ち、図５は、安定性余裕代ＳＴＢに基づ
いて、安定性補正率ＬＳＴＢを構成する２個の補正率Ｌ
ＳＴＢ1，ＬＳＴＢ2をそれぞれ求めるための補正率マッ
プを示し、この補正率マップは、実機試験によって、安
定性余裕代ＳＴＢの値を変化させながら、そのとき機関
が実際に必要とする燃料増量補正（ＫAS＋ＫTW）を測定
することにより、安定性余裕代ＳＴＢ（又は最大安定性
余裕代ＳＴＢMAX）と安定側補正率ＬＳＴＢ1（又は不安
定側補正率ＬＳＴＢ2）との関係をマップ化したもので
あり、安定側補正率ＬＳＴＢ1も不安定側補正率ＬＳＴ
Ｂ2も、この同じ単一の補正率マップによって求められ
る。安定性補正率ＬＳＢは、後述の如く、機関の安定性
を示す要素である安定側補正率ＬＳＴＢ1と、機関の不
安定性を示す要素である不安定側補正率ＬＳＴＢ2とか
ら構成されており（ＬＳＴＢ＝ＬＳＴＢ1−ＬＳＴ
Ｂ2）、安定性要素と不安定性要素との両者の力関係に
応じて、燃料増量補正を減量させるためのものである。
従って、機関が安定するほど安定側補正率ＬＳＴＢ1が
大きくなり、機関が不安定になるほど不安定側補正率Ｌ
ＳＴＢ2が大きくなるように、この補正率マップは構成
されている。That is, FIG. 5 shows the two correction factors L constituting the stability correction factor LSTB based on the stability margin allowance STB.
A correction factor map for obtaining STB 1 and LSTB 2 is shown, and this correction factor map changes the value of the stability margin STB by an actual machine test, and at the same time, the fuel increase correction required by the engine at that time. By measuring (K AS + K TW ), the relationship between the stability margin STB (or maximum stability margin STB MAX ) and the stable correction rate LSTB 1 (or unstable correction rate LSTB 2 ) is mapped. The stable correction factor LSTB 1 is also the unstable correction factor LST.
B 2 is also obtained by this same single correction factor map. As will be described later, the stability correction factor LSB is composed of a stable correction factor LSTB 1 which is an element showing the stability of the engine and an unstable correction factor LSTB 2 which is an element showing the instability of the engine. (LSTB = LSTB 1 −LST
B 2 ) is for reducing the fuel increase correction according to the force relationship between the stability factor and the instability factor.
Therefore, the stable side correction factor LSTB 1 increases as the engine stabilizes, and the unstable side correction factor L increases as the engine becomes unstable.
This correction rate map is configured so that STB 2 becomes large.
【００４４】ここで、安定側補正率ＬＳＴＢ1を設定す
るために、現時点での安定性余裕代ＳＴＢを用いず、最
大安定性余裕代ＳＴＢMAXを用いることとしたのは、燃
料性状と最大安定性余裕代ＳＴＢとの関係が密接だから
である。即ち、例えば軽質燃料を用いた場合は、始動直
後の安定性（安定性余裕代ＳＴＢ）が高い。一方、重質
燃料を用いた場合は、蒸発点が高く壁流が多くなるた
め、混合気の濃度が薄まり、始動直後の安定性が低い。
従って、安定性余裕代ＳＴＢと燃料性状との間には相関
関係が成立するが、後述の如く、燃料増量補正係数（Ｋ
AS＋ＫTW）による燃料の増量が減量調整されるため、こ
の燃料増量の調整に応じて安定性余裕代ＳＴＢは、時間
と共に変化していく。これに対し、最大安定性余裕代Ｓ
ＴＢMAXは、燃料増量の調整が十分行われる前の初期段
階で燃料性状によって定まる値であるため、重質燃料で
あるか軽質燃料であるかの燃料性状の情報を正確に記憶
していることになる。従って、本実施例では、ステップ
１５で、燃料性状の情報を記憶した最大安定性余裕代Ｓ
ＴＢMAXを用いることにより、安定側補正率ＬＳＴＢ1を
求めている。Here, in order to set the stable side correction factor LSTB 1 , it is decided to use the maximum stability margin allowance STB MAX without using the present stability margin allowance STB because of the fuel property and the maximum stability margin STB MAX. This is because the relationship with the margin allowance STB is close. That is, for example, when a light fuel is used, the stability immediately after the start (stability margin STB) is high. On the other hand, when the heavy fuel is used, the evaporation point is high and the wall flow is large, so that the concentration of the air-fuel mixture becomes thin and the stability immediately after the start is low.
Therefore, although a correlation is established between the stability margin STB and the fuel property, as will be described later, the fuel increase correction coefficient (K
Since the amount of fuel increase due to ( AS + K TW ) is adjusted, the stability margin STB changes with time in accordance with the adjustment of this fuel increase. On the other hand, the maximum stability margin S
Since TB MAX is a value determined by the fuel property in the initial stage before the adjustment of the fuel increase amount is sufficiently performed, it is necessary to accurately store the information on the fuel property of the heavy fuel or the light fuel. become. Therefore, in this embodiment, in step 15, the maximum stability margin S that stores the information on the fuel property is stored.
The stable correction factor LSTB 1 is obtained by using TB MAX .
【００４５】次に、ステップ１６では、不安定側補正率
ＬＳＴＢ2の値を設定するが、現時点で機関の回転は安
定しており、前記ステップ１４によって機関の安定性に
余裕があると判定されているため、不安定要素は存在し
ない。従って、このステップ１６では不安定側補正率Ｌ
ＳＢ2の値を「０」とする。Next, at step 16, the value of the unstable side correction factor LSTB 2 is set. At this moment, the rotation of the engine is stable and it is judged at step 14 that the stability of the engine has a margin. Therefore, there are no instability factors. Therefore, in this step 16, the unstable side correction factor L
The value of SB 2 is set to “0”.
【００４６】一方、前記ステップ１４で「ＮＯ」と判定
したときは、機関の回転が不安定の場合であるため、ス
テップ１７では、燃料性状が反映された安定側補正率Ｌ
ＳＴＢ1の値を保持しておく。次に、ステップ１８で
は、上述した補正率マップにより、現在の安定性余裕代
ＳＴＢから不安定側補正率ＬＳＴＢ2を読み出す。ここ
で、機関が不安定時（ＳＴＢ＜０）の場合であるから、
安定性余裕代ＳＴＢは負の値である。従って、補正率マ
ップでは、不安定時の安定性余裕代ＳＴＢの絶対値（｜
ＳＴＢ｜）に基づいて不安定側補正率ＬＳＴＢ2を読み
出す。従って、機関の不安定性が大きくなるほど補正率
マップから読み出される不安定側補正率ＬＳＴＢ2の値
が大きくなる。そして、ステップ１９では、補正率マッ
プによって求められた安定側補正率ＬＳＴＢ1と不安定
側補正率ＬＳＴＢ2とから、下記数４によって安定性補
正率ＬＳＴＢを算出する。On the other hand, if "NO" is determined in step 14, it means that the rotation of the engine is unstable. Therefore, in step 17, the stable correction factor L reflecting the fuel property is reflected.
Hold the value of STB 1 . Next, at step 18, the unstable side correction factor LSTB 2 is read from the current stability margin STB by the above-mentioned correction factor map. Here, since the engine is unstable (STB <0),
The stability margin STB is a negative value. Therefore, in the correction factor map, the absolute value (|
The unstable side correction factor LSTB 2 is read based on STB |). Therefore, as the instability of the engine increases, the value of the unstable correction factor LSTB 2 read from the correction factor map increases. Then, in step 19, the stability correction rate LSTB is calculated by the following equation 4 from the stable side correction rate LSTB 1 and the unstable side correction rate LSTB 2 obtained from the correction rate map.
【００４７】[0047]
【数４】ＬＳＴＢ＝ＬＳＴＢ1−ＬＳＴＢ2 最後に、ステップ２０では、安定性補正率ＬＳＴＢと上
述した低水温時の燃料増量補正係数である始動後増量補
正係数ＫAS及び水温増量補正係数ＫTWとに基づいて、下
記数５により、安定性補正係数ＫSTBを演算する。[Formula 4] LSTB = LSTB 1 −LSTB 2 Finally, in step 20, the stability correction factor LSTB and the post-starting amount increase correction factor K AS and the water temperature amount increase correction factor K TW which are the above-mentioned fuel amount increase correction factors at low water temperature are calculated. Based on the following, the stability correction coefficient K STB is calculated by the following equation 5.
【００４８】[0048]
【数５】ＫSTB＝ＬＳＴＢ×(ＫAS＋ＫTW) ここで、上述した安定性補正率ＬＳＴＢの値は、下記数
６に示す通り、「０」から「１」までの範囲内で変化す
るように制限されている。[Formula 5] K STB = LSTB × (K AS + K TW ) Here, the value of the above-mentioned stability correction factor LSTB changes within the range from “0” to “1” as shown in the following Formula 6. Is restricted to.
【００４９】[0049]
【数６】０≦ＬＳＴＢ≦１ 即ち、安定性補正率ＬＳＴＢが最小値「０」をとったと
きは、数５に示す安定性補正係数ＫSTBも「０」となる
ため、図６と共に後述する空燃比設定補正係数ＴＦＢＹ
Ａの演算において、低水温時の燃料増量に対する減量が
全く行われないことになる（（ＫAS＋ＫTW）−０＝ＫAS
＋ＫTW）。一方、安定性補正率ＬＳＴＢが最大値「１」
をとったときは、安定性補正係数ＫSTBは（ＫAS＋
ＫTW）となり、空燃比設定補正係数ＴＦＢＹＡの演算に
おいて、低水温時の燃料増量に対する減量が１００％行
われ、燃料増量が全く行われないことになる（（ＫAS＋
ＫTW）−（ＫAS＋ＫTW）＝０）。[Equation 6] 0 ≦ LSTB ≦ 1 That is, when the stability correction rate LSTB takes the minimum value “0”, the stability correction coefficient K STB shown in Equation 5 is also “0”, and will be described later with reference to FIG. A / F ratio setting correction coefficient TFBY
In the calculation of A, there is no reduction in fuel amount at low water temperature ((K AS + K TW ) −0 = K AS
+ K TW ). On the other hand, the stability correction factor LSTB is the maximum value "1".
Is calculated , the stability correction coefficient K STB becomes (K AS +
K TW ), and in the calculation of the air-fuel ratio setting correction coefficient TFBYA, the fuel amount is reduced by 100% relative to the fuel amount increase at the low water temperature, and the fuel amount increase is not performed at all ((K AS +
K TW )-(K AS + K TW ) = 0).
【００５０】次に、図６のフローチャートを参照しつ
つ、空燃比設定補正係数ＴＦＢＹＡの演算処理の内容を
説明する。まず、ステップ３１〜ステップ３５では、上
述した各補正係数の値を演算する。即ち、ステップ３１
では始動後増量補正係数ＫASを、ステップ３２では水温
増量補正係数ＫTWを、ステップ３３では高水温増量補正
係数ＫHOTを、ステップ３４ではノック制御リタード時
増量補正係数ＭＲＫNKを、ステップ３５では混合比割付
補正係数ＫMRを、それぞれ演算する。Next, the contents of the calculation process of the air-fuel ratio setting correction coefficient TFBYA will be described with reference to the flowchart of FIG. First, in steps 31 to 35, the values of the above-described correction coefficients are calculated. That is, step 31
In the after-start increment correction coefficient K AS, the water temperature increase correction coefficient K TW In step 32, the high water temperature increase correction coefficient K HOT In step 33, the time increment correction coefficient MRK NK In the knock control retard step 34, step 35 The mixing ratio allocation correction coefficient K MR is calculated respectively.
【００５１】次に、ステップ３６では、上述した図４の
フローチャートによって、安定性補正係数ＫSTBを演算
し、最後にステップ３６では、これら各補正係数ＫAS，
ＫTW，ＫHOT，ＭＲＫNK，ＫMR，ＫSTBから、下記数７に
より、空燃比設定補正係数ＴＦＢＹＡを演算する。Next, at step 36, the stability correction coefficient K STB is calculated according to the above-mentioned flowchart of FIG. 4, and finally at step 36, each of these correction coefficients K AS ,
From K TW , K HOT , MRK NK , K MR , and K STB , the air-fuel ratio setting correction coefficient TFBYA is calculated by the following equation 7.
【００５２】[0052]
【数７】ＴＦＢＹＡ＝ＫAS＋ＫTW＋ＫHOT＋ＭＲＫNK＋
ＫMR−ＫSTB ここで、安定性補正係数ＫSTBは、数５に示す通り、安
定性補正率ＬＳＴＢと燃料増量補正係数（ＫAS＋ＫTW）
との積であるから、これを前記数７に代入すると、下記
数８が得られる。[Formula 7] TFBYA = K AS ＋ K TW ＋ K HOT ＋ MRK NK ＋
K MR −K STB Here, the stability correction coefficient K STB is, as shown in Equation 5, the stability correction rate LSTB and the fuel increase correction coefficient (K AS + K TW ).
Substituting this into Equation 7 yields Equation 8 below.
【００５３】[0053]
【数８】ＴＦＢＹＡ＝ＫAS＋ＫTW＋ＫHOT＋ＭＲＫNK＋
ＫMR−ＬＳＴＢ×(ＫAS＋ＫTW) 即ち、数８から明らかなように、この安定性補正係数Ｋ
STBは、各燃料増量補正係数（ＫAS＋ＫTW）によって行
われる冷間始動時の燃料増量に対する減量調整を行うも
のである。[Equation 8] TFBYA = K AS + K TW + K HOT + MRK NK +
K MR −LSTB × (K AS + K TW ) That is, as is clear from Equation 8, this stability correction coefficient K
The STB adjusts the amount of fuel increase during cold start performed by each fuel amount increase correction coefficient (K AS + K TW ).
【００５４】次に、燃料噴射量Ｔiの演算処理につい
て、図７のフローチャートを参照しつつ説明する。ま
ず、ステップ４１では、機関回転数Ｎと吸入空気量Ｑと
から基本噴射量ＴPを演算し、ステップ４２では図６の
フローチャートによって空燃比設定補正係数ＴＦＢＹＡ
を演算する。ステップ４３では、空燃比フィードバック
補正係数αを演算し、ステップ４４では、空燃比補正学
習値αmを演算する。そして、ステップ４５では、電圧
補正ＴSを求め、最後にステップ４６では、燃料噴射量
Ｔiを下記数９によって演算する。Next, the calculation process of the fuel injection amount T i will be described with reference to the flowchart of FIG. First, at step 41, the basic injection amount T P is calculated from the engine speed N and the intake air amount Q, and at step 42, the air-fuel ratio setting correction coefficient TFBYA is calculated according to the flowchart of FIG.
Is calculated. In step 43, the air-fuel ratio feedback correction coefficient α is calculated, and in step 44, the air-fuel ratio correction learning value α m is calculated. Then, in step 45, the voltage correction T S is obtained, and finally in step 46, the fuel injection amount T i is calculated by the following equation 9.
【００５５】[0055]
【数９】Ｔi＝ＴP×(α＋αm)×ＴＦＢＹＡ＋ＴS 本実施例は、このように構成されるもので、例えば軽質
燃料を用いた場合は、揮発性が高く、安定性指標ＴＲＦ
ＳＵＭが安定性許容レベルＳＴＢＳＬから離れて始動直
後の安定性余裕代ＳＴＢが大きくなるため、安定側補正
率ＬＳＴＢ1は最大安定性余裕代ＳＴＢMAXに基づいて求
められ、不安定側補正率ＬＳＴＢ2には「０」がセット
される。従って、安定性補正率ＬＳＴＢの値は、軽質燃
料の揮発性の良さ、応答性の良さに応じて大きくなるた
め、このＬＳＴＢの値に応じて安定性補正係数ＫSTBの
値も大きくなり、空燃比設定補正係数ＴＦＢＹＡの値が
小さくなる。これにより、低水温時に行われる燃料増量
（ＫAS＋ＫTW）が抑制され、不必要な燃料噴射が防止さ
れる。[Equation 9] T i = T P × (α + α m ) × TFBYA + T S This embodiment is configured in this way. For example, when a light fuel is used, the volatility is high and the stability index TRF is high.
Since the SUM moves away from the stability allowable level STBSL and the stability margin STB immediately after starting increases, the stable side correction rate LSTB 1 is obtained based on the maximum stability margin STB MAX , and the unstable side correction rate LSTB 2 Is set to "0". Therefore, the value of the stability correction factor LSTB increases in accordance with the volatility and responsiveness of the light fuel, and the value of the stability correction coefficient K STB also increases in accordance with the value of this LSTB, and The value of the fuel ratio setting correction coefficient TFBYA becomes smaller. As a result, the fuel increase (K AS + K TW ) performed at low water temperature is suppressed, and unnecessary fuel injection is prevented.
【００５６】また、この燃料増量の減量調整が行われた
結果、万が一、燃料噴射量が少なくなり過ぎて機関が不
安定になった場合は、安定性指標ＴＲＦＳＵＭが安定性
許容レベルＳＴＢＳＬを越えてマイナス側に入り、安定
性余裕代ＳＴＢが負の値をとるため、不安定側補正率Ｌ
ＳＴＢ2の値が「０」からこの不安定時の安定性余裕代
ＳＴＢの絶対値に基づいて変更される。従って、不安定
側補正率ＬＳＴＢ2の値が大きくなり、安定性補正係数
ＫSTBの値が不安定度合に応じて小さくなるため、低水
温時の燃料増量補正係数（ＫAS＋ＫTW）の値が減少す
る。これにより、空燃比設定補正係数ＴＦＢＹＡの値が
大きくなって、燃料増量に対する過度の減量が速やかに
修正され、ただちに機関は安定状態に回復する。As a result of this reduction adjustment of the fuel increase, if the fuel injection amount becomes too small and the engine becomes unstable, the stability index TRFSUM exceeds the stability allowable level STBSL. Since the stability margin STB takes a negative value on the negative side, the unstable side correction factor L
The value of STB 2 is changed from “0” based on the absolute value of the stability margin STB at the time of instability. Therefore, the value of the unstable side correction factor LSTB 2 becomes large, and the value of the stability correction coefficient K STB becomes small according to the degree of instability, so the value of the fuel increase correction coefficient (K AS + K TW ) at low water temperature Is reduced. As a result, the value of the air-fuel ratio setting correction coefficient TFBYA becomes large, the excessive reduction in fuel quantity is promptly corrected, and the engine is immediately restored to a stable state.
【００５７】一方、重質燃料を用いた場合には、揮発性
が低く、始動直後の安定状態に殆ど余裕が生じないた
め、安定性余裕代ＳＴＢは「０」に近い正の値となる
（ＳＴＢ≒０）。また、安定性に殆ど余裕がない重質燃
料であるため、最大安定性余裕代ＳＴＢMAXの値も安定
性余裕代ＳＴＢの値と略同程度となり、「０」に近い値
をとることになる（ＳＴＢMAX≒０）。従って、実質的
に「０」に近い値である最大安定性余裕代ＳＴＢMAXに
基づいて求められる安定側補正率ＬＳＴＢ1と、強制的
に「０」に設定された不安定側補正率ＬＳＴＢ2との差
分も略「０」となり、両者の差である安定性補正率ＬＳ
ＴＢも殆ど「０」と等しくなるため（ＬＳＴＢ≒０）、
安定性補正係数ＫSTBの値も略「０」となる（ＫSTB≒
０）。On the other hand, when heavy fuel is used, since the volatility is low and there is almost no margin in the stable state immediately after the start, the stability margin STB has a positive value close to "0" ( STB≈0). Further, since it is a heavy fuel with almost no margin in stability, the value of maximum stability margin STB MAX is also approximately the same as the value of stability margin STB, and takes a value close to “0”. (STB MAX ≈ 0). Therefore, the stable correction rate LSTB 1 obtained based on the maximum stability margin STB MAX which is substantially close to “0” and the unstable correction rate LSTB 2 forcedly set to “0”. And the difference between the two is approximately “0”, which is the difference between the two.
TB is almost equal to “0” (LSTB≈0),
The value of the stability correction coefficient K STB is also substantially “0” (K STB ≈
0).
【００５８】これにより、低水温時の燃料増量（ＫAS＋
ＫTW）が殆ど抑制されないことになるが、もともと、こ
の低水温時の燃料増量補正係数（ＫAS＋ＫTW）は、予め
始動性の低い重質燃料用に設定されているため、安定性
補正係数ＫSTBによる減量調整がされずに初期設定のま
まで燃料増量が行われることにより、十分な燃料が噴射
供給され、機関は安定する。As a result, the fuel quantity increase (K AS +
K TW ) is hardly suppressed, but the fuel increase correction coefficient (K AS + K TW ) at low water temperature is originally set for heavy fuel with low startability, so stability correction is performed. By increasing the fuel amount with the initial setting without adjusting the reduction amount by the coefficient K STB , sufficient fuel is injected and supplied, and the engine is stabilized.
【００５９】なお、標準燃料を用いた場合は、図５に示
す補正率マップにより、安定側補正率ＬＳＴＢ1の値が
軽質燃料のＬＳＴＢ1と重質燃料のＬＳＴＢ1との中間に
位置し、安定性補正率ＬＳＴＢも安定性補正係数ＫSTB
も中間程度の値となるため、重質燃料と軽質燃料の略中
間で燃料増量が行われる。When the standard fuel is used, according to the correction rate map shown in FIG. 5, the stable side correction rate LSTB 1 is located between the light fuel LSTB 1 and the heavy fuel LSTB 1 , The stability correction factor LSTB is also the stability correction coefficient K STB.
Also becomes an intermediate value, the fuel amount is increased approximately at the middle of the heavy fuel and the light fuel.
【００６０】このように、本実施例によれば、以下の効
果を奏する。As described above, according to this embodiment, the following effects are obtained.
【００６１】第１に、冷間始動直後の回転変動に基づい
て安定性指標ＴＲＦＳＵＭを求め、この安定性指標ＴＲ
ＦＳＵＭと予め実機試験により各運転条件毎に定められ
た安定性許容レベルＳＴＢＳＬとを比較して、両者の差
分を安定性余裕代ＳＴＢとして演算し、この安定性余裕
代ＳＴＢに基づいて燃料性状を判別する構成としたた
め、燃料性状を正確に判別することができ、この燃料性
状に応じて燃料噴射量の制御を行うことができる。即
ち、始動直後の機関の回転変動には、燃料性状に起因す
る燃料の応答性（揮発性）や燃料と空気との混合状態が
反映されるため、始動時回転数の立ち上がりパターンで
燃料性状を判別する第２の従来技術とは異なり、燃料性
状を正確に判別することができる。First, the stability index TRFSUM is obtained based on the rotational fluctuation immediately after the cold start, and the stability index TR is calculated.
The FSUM is compared with the stability allowable level STBSL that has been previously determined for each operating condition by an actual machine test, the difference between the two is calculated as the stability margin STB, and the fuel property is determined based on this stability margin STB. Since the determination is made, the fuel property can be accurately determined, and the fuel injection amount can be controlled according to the fuel property. That is, the rotational fluctuation of the engine immediately after starting reflects the responsiveness (volatility) of the fuel and the mixed state of the fuel and air due to the fuel property. Unlike the second prior art for determining, the fuel property can be accurately determined.
【００６２】第２に、安定性余裕代ＳＴＢのうち最大安
定性余裕代ＳＴＢMAXの値に基づいて安定側補正率ＬＳ
ＴＢ1を演算する構成としたため、燃料性状を正確に判
別して安定側補正率ＬＳＴＢ1に記憶しておくことがで
きる。即ち、安定性余裕代ＳＴＢは燃料増量制御によっ
て変化するものの、最大安定性余裕代ＳＴＢMAXは燃料
性状によって定まるため、この最大安定性余裕代ＳＴＢ
MAXに基づいて安定側補正率ＬＳＴＢ1を求めることによ
り、燃料性状を正確に判別して最適な燃料増量を行うこ
とができる。Secondly, based on the value of the maximum stability margin STB MAX of the stability margin STB, the correction factor LS on the stable side is calculated.
Since TB 1 is calculated, the fuel property can be accurately determined and stored in the stable correction factor LSTB 1 . That is, the stability margin STB changes depending on the fuel amount increase control, but the maximum stability margin STB MAX is determined by the fuel property.
By obtaining the stable correction factor LSTB 1 based on MAX , it is possible to accurately determine the fuel property and perform the optimum fuel increase.
【００６３】第３に、低水温時の燃料増量補正係数（Ｋ
AS＋ＫTW）の値を調整するための安定性補正係数ＫSTB
を安定性余裕代ＳＴＢに基づいて演算し、この安定性補
正係数ＫSTBと低水温時の燃料増量補正係数（ＫAS＋Ｋ
TW）と基本噴射量ＴP等とに基づいて、数８及び数９に
示す如く、燃料噴射量Ｔiを演算する構成としたため、
燃料性状に起因する安定性余裕代ＳＴＢに応じて、燃料
噴射量Ｔiを最適制御することができる。Third, the fuel increase correction coefficient (K
Stability correction factor K STB for adjusting the value of ( AS + K TW ).
Is calculated based on the stability margin STB, and the stability correction coefficient K STB and the fuel increase correction coefficient (K AS + K at low water temperature) are calculated.
TW ) and the basic injection amount T P, etc., the fuel injection amount T i is calculated as shown in Eqs.
The fuel injection amount T i can be optimally controlled according to the stability margin STB resulting from the fuel property.
【００６４】第４に、安定性余裕代ＳＴＢが所定の基準
値「０」以上の場合は、最大安定性余裕代ＳＴＢMAXに
基づいて安定性補正係数ＫSTBを演算し、安定性余裕代
ＳＴＢが所定の基準値「０」未満の場合は、最大安定性
余裕代ＳＴＢMAXと現在の安定性余裕代ＳＴＢとの差分
に基づいて安定性補正係数ＫSTBを演算する構成とした
ため、機関が安定して安定性余裕代ＳＴＢがある場合
は、燃料性状に応じて燃料噴射量を制御することがで
き、機関が不安定になり安定性余裕代ＳＴＢがなくなっ
た場合は、その不安定の度合に応じて安定性補正係数Ｋ
STBを修正し、機関を速やかに安定状態に導くことがで
きる。即ち、燃料性状に応じた燃料増量制御を行いつつ
機関の現時点の安定性をフィードバックすることがで
き、冷間始動時の運転性等を安定化することができる。Fourthly, when the stability margin allowance STB is equal to or larger than the predetermined reference value "0", the stability correction coefficient K STB is calculated based on the maximum stability margin allowance STB MAX , and the stability margin allowance STB is calculated. Is less than the predetermined reference value “0”, the stability correction coefficient K STB is calculated based on the difference between the maximum stability margin STB MAX and the current stability margin STB, so that the engine is stable. If there is a stability margin STB, the fuel injection amount can be controlled according to the fuel property, and if the stability margin STB disappears due to the engine becoming unstable, the degree of instability Depending on the stability correction coefficient K
The STB can be modified to bring the engine to a stable state quickly. That is, it is possible to feed back the current stability of the engine while performing the fuel increase control according to the fuel property, and to stabilize the drivability at the cold start.
【００６５】第５に、低水温時の燃料増量補正係数（Ｋ
AS＋ＫTW）を予め始動性が低い重質燃料に応じて設定
し、安定性補正係数ＫSTBを「０」から低水温時の燃料
増量補正係数（ＫAS＋ＫTW）の値までの範囲内で変化さ
せる構成としたため、重質燃料を用いた場合は、重質燃
料用に設定された燃料増量を十分に行うことにより、こ
の燃料性状に最適な空燃比を得ることができ、機関を速
やかに安定化させて冷間始動時の始動性を確保すること
ができる。一方、軽質燃料を用いた場合には、安定性補
正係数ＫSTBの値を小さくして、重質燃料用に設定され
た燃料増量補正係数（ＫAS＋ＫTW）による燃料増量を軽
質燃料に合わせて抑制できる。この結果、機関の安定性
を維持しつつ不必要な燃料噴射の増量を防止して、燃費
を向上することができると共に、エミッション排出量を
低減することができる。Fifth, the fuel increase correction coefficient (K
AS + K TW ) is set in advance according to the heavy fuel with low startability, and the stability correction coefficient K STB is within the range from "0" to the fuel increase correction coefficient (K AS + K TW ) at low water temperature. When heavy fuel is used, it is possible to obtain the optimum air-fuel ratio for this fuel property by sufficiently increasing the amount of fuel set for heavy fuel. It is possible to secure the startability at the cold start by stabilizing it. On the other hand, when a light fuel is used, the value of the stability correction coefficient K STB is reduced and the fuel increase correction coefficient (K AS + K TW ) set for heavy fuel is adjusted to the light fuel. Can be suppressed. As a result, it is possible to prevent unnecessary increase in fuel injection while maintaining the stability of the engine, improve fuel efficiency, and reduce emission emissions.
【００６６】図８は、本実施例による燃料増量制御を行
った場合の空燃比と安定性の変化を示したもので、同図
中、実線で示すＡは、軽質燃料を用いて本実施例による
増量制御を行った場合の特性変化を示し、破線で示すＢ
は、重質燃料を用いて本実施例による増量制御を行った
場合の特性変化と、軽質燃料を用いた場合の従来技術に
よる特性変化との双方を示している。この図８によれ
ば、軽質燃料を用いて本実施例による燃料増量制御を行
った場合は、始動後速やかに、燃料の増量が抑制されて
最低限の安定性が維持されつつ、吸入側の空燃比が燃料
性状に好ましい理論空燃比近傍に達しているのが理解で
きる。これに対し、軽質燃料の燃料増量を従来技術（数
１）によって制御した場合には、空燃比が理論空燃比に
達するまでに本実施例よりも時間ｔだけ長くかかる上
に、安定性許容レベルＳＴＢＳＬに対して不要な安定性
余裕代ΔＳＴＢを有するため、本実施例に比較して燃費
が低下し、エミッション排出量が増加する。なお、機関
が始動すると、機関回転が安定するまでに通常１〜２秒
程度かかるため、この間はＴＲＥＦのサンプリングを行
わない。FIG. 8 shows changes in the air-fuel ratio and stability when the fuel amount increase control according to this embodiment is performed. In FIG. 8, the solid line A indicates that this embodiment uses light fuel. B shows the characteristic change when the increase control is performed by
Shows both the characteristic change when the increase control according to the present embodiment is performed using heavy fuel, and the characteristic change according to the conventional technique when light fuel is used. According to FIG. 8, when the fuel increase control according to the present embodiment is performed using the light fuel, the fuel increase is suppressed immediately after the start and the minimum stability is maintained, and the intake side of the intake side is maintained. It can be understood that the air-fuel ratio has reached the vicinity of the theoretical air-fuel ratio, which is preferable for fuel properties. On the other hand, when the fuel increase amount of the light fuel is controlled by the conventional technique (Equation 1), it takes longer time t than the present embodiment until the air-fuel ratio reaches the stoichiometric air-fuel ratio, and the stability allowable level is increased. Since the STBSL has an unnecessary stability allowance ΔSTB, the fuel consumption is reduced and the emission amount of emission is increased as compared with the present embodiment. When the engine is started, it usually takes about 1 to 2 seconds until the engine rotation stabilizes, so that TREF is not sampled during this period.
【００６７】また、第２の従来技術（特開平３−２６８
４１号公報）では、燃料性状補正係数ＫＦＨの値を標準
燃料の場合に「１」とし、重質燃料及び軽質燃料の場合
は、それぞれ水温に応じて予め用意されたテーブルを参
照することにより求める構成となっている。従って、第
２の従来技術によるものでは、システム構成が複雑化す
るばかりか、重質燃料に対する燃料増量に時間遅れが生
じる可能性があるが、本実施例では、燃料増量の初期設
定を始動性等が最も懸念される重質燃料に対応させて、
重質燃料を用いた場合の始動性、運転性をまず最初に確
保し、安定性に余裕があると判断した場合のみ減量制御
を行う構成であるため、重質燃料を用いた場合の始動性
や運転性と、軽質燃料を用いた場合の燃費の向上及びエ
ミッションの低減との双方を両立させることができる。A second conventional technique (Japanese Patent Laid-Open No. 3-268)
41), the value of the fuel property correction coefficient KFH is set to "1" in the case of standard fuel, and in the case of heavy fuel and light fuel, it is determined by referring to a table prepared in advance according to the water temperature. It is composed. Therefore, according to the second conventional technique, not only the system configuration becomes complicated, but also there is a possibility that a time delay occurs in the fuel amount increase for the heavy fuel, but in the present embodiment, the initial setting of the fuel amount increase can be started. In response to heavy fuel, which is of the greatest concern,
The startability and drivability when using heavy fuel is first ensured, and the weight reduction control is performed only when it is judged that there is a margin of stability, so startability when using heavy fuel It is possible to achieve both the improvement in fuel efficiency and the reduction in emissions when using light fuel, as well as drivability.
【００６８】第６に、クランク角センサ２０が各気筒の
点火に応じて出力したＲＥＦ信号間の時間ＴＲＥＦを求
め、このＲＥＦ信号間時間ＴＲＥＦの変動を気筒別変化
量ＴＲＥＦＣとして各気筒毎に演算し、この気筒別変化
量ＴＲＥＦＣを隣接する気筒間で比較して周期変動ＴＲ
ＦＯＵＴを求め、この周期変動ＴＲＦＯＵＴを所定サイ
クルＮＣだけ積算することにより、安定性指標ＴＲＦＳ
ＵＭを得る構成としたから、ＲＥＦ信号間のバラツキや
機関の増速，減速に影響されずに、機関の安定状態を正
確に知ることができる。また、既に機関に設けられてい
るクランク角センサ２０を利用して安定性指標ＴＲＦＳ
ＵＭを求める構成のため、別体の性状判別センサを用い
る必要がなく、低コストに機関の始動性や運転性を大幅
に向上することができる。Sixth, the time TREF between the REF signals output by the crank angle sensor 20 in response to the ignition of each cylinder is obtained, and the fluctuation of the time TREF between the REF signals is calculated for each cylinder as a variation amount TREFC for each cylinder. Then, the cylinder-by-cylinder change amount TREFC is compared between the adjacent cylinders, and the cycle fluctuation TR is compared.
The stability index TRFS is obtained by obtaining FOUT and integrating this cycle fluctuation TRFOUT for a predetermined cycle NC.
Since the configuration is such that UM is obtained, the stable state of the engine can be accurately known without being affected by the variation between the REF signals and the acceleration and deceleration of the engine. In addition, the stability index TRFS is calculated using the crank angle sensor 20 already provided in the engine.
Since the configuration is such that the UM is obtained, it is not necessary to use a separate property determination sensor, and the startability and drivability of the engine can be greatly improved at low cost.
【００６９】第７に、安定性補正率ＬＳＴＢを構成する
安定側補正率ＬＳＴＢ1と不安定側補正率ＬＳＴＢ2と
を、図５に示す同一の補正率マップから読み出す構成と
したため、全体構成を簡素化することができる。Seventh, the stable side correction rate LSTB 1 and the unstable side correction rate LSTB 2 constituting the stability correction rate LSTB are read out from the same correction rate map shown in FIG. It can be simplified.
【００７０】なお、前記実施例では、低水温時の燃料増
量補正係数として、始動時増量補正係数ＫASと水温増量
補正係数ＫTWとの２つを例示したが、本発明はこれに限
らず、低水温時に燃料の増量を行う補正係数であれば適
用可能である。例えば、前記各補正係数ＫAS，ＫTWに代
表される水温時の燃料増量補正係数を、上位概念として
ＫCと表現すれば、前記安定性補正係数ＫSTBは、ＫSTB
＝ＬＳＴＢ×ＫCとして表すことができる。In the above embodiment, two examples of the fuel increase correction coefficient at low water temperature, that is, the startup increase correction coefficient K AS and the water temperature increase correction coefficient K TW are exemplified, but the present invention is not limited to this. Any correction coefficient that increases the amount of fuel when the water temperature is low can be applied. For example, if the fuel increase correction coefficient at water temperature represented by the correction coefficients K AS and K TW is expressed as K C as a superordinate concept, the stability correction coefficient K STB becomes K STB.
= LSTB × K C
【００７１】また、前記実施例では、安定性の判断基準
としての所定の基準値に「０」を用いる場合を例に挙げ
て説明したが、これは主として安定性許容レベルＳＴＢ
ＳＬをどのレベルに設定するかで定まるものであるか
ら、「０」以外の任意の数値を所定の基準値βとして用
いてもよい。In the above embodiment, the case where "0" is used as the predetermined reference value as the stability judgment standard has been described as an example, but this is mainly the stability allowable level STB.
Since it is determined by which level SL is set, any numerical value other than "0" may be used as the predetermined reference value β.
【００７２】さらに、前記実施例では、各補正率ＬＳＴ
Ｂ1，ＬＳＴＢ2を図５に示す同一の補正率マップで求め
る場合を例示したが、これに限らず、各補正率ＬＳＴＢ
1，ＬＳＴＢ2毎にそれぞれ別体のマップを用意する構成
としてもよい。この場合には、最大安定性余裕代ＳＴＢ
MAX又は安定性余裕代ＳＴＢの絶対値に対する変化の割
合を、各補正率ＬＳＴＢ1，ＬＳＴＢ2毎にそれぞれ個別
に設定することもできる。Further, in the above embodiment, each correction factor LST
Although the case where B 1 and LSTB 2 are obtained by the same correction rate map shown in FIG. 5 has been illustrated, the present invention is not limited to this, and each correction rate
Alternatively, a separate map may be prepared for each of 1 and LSTB 2 . In this case, the maximum stability margin STB
It is also possible to individually set the rate of change of the MAX or the stability margin STB with respect to the absolute value for each of the correction factors LSTB 1 and LSTB 2 .
【００７３】[0073]
【発明の効果】以上詳述した通り、本発明に係る内燃機
関の制御装置によれば、回転数検出手段が検出した回転
数に基づいて安定性指標を求め、この安定性指標と予め
定められた安定性許容レベルとを比較して、両者の差分
を安定性余裕代として演算し、この安定性余裕代に基づ
いて燃料性状を判別する構成としたため、燃料性状を正
確に判別することができ、この燃料性状に応じて燃料噴
射量の制御を行うことができる。As described in detail above, according to the control device for an internal combustion engine of the present invention, a stability index is obtained based on the rotation speed detected by the rotation speed detecting means, and this stability index is predetermined. Since the difference between the two is calculated as the stability margin and the fuel property is determined based on this stability margin, the fuel property can be accurately determined. The fuel injection amount can be controlled according to the fuel property.
【００７４】また、最大安定性余裕代と所定の基準値と
を比較することにより燃料性状を判別する構成としたた
め、燃料性状の判別を安定化することができる。Further, since the fuel property is determined by comparing the maximum stability margin and the predetermined reference value, the determination of the fuel property can be stabilized.
【００７５】さらに、燃料性状を反映した安定性余裕代
に基づいて、低水温時の燃料増量補正係数を補正するた
めの安定性補正係数を演算し、この安定性補正係数と低
水温時の燃料増量補正係数と機関の運転条件に応じて定
まる基本噴射量とに基づいて燃料噴射量を演算する構成
としたため、冷間始動時の燃料噴射量を燃料性状に応じ
て制御することができる。Further, a stability correction coefficient for correcting the fuel increase correction coefficient at low water temperature is calculated based on the stability margin margin reflecting the fuel property, and the stability correction coefficient and the fuel at low water temperature are calculated. Since the fuel injection amount is calculated based on the increase correction coefficient and the basic injection amount determined according to the operating condition of the engine, the fuel injection amount at the cold start can be controlled according to the fuel property.
【００７６】また、安定性余裕代が所定の基準値以上の
ときは最大安定性余裕代に基づいて安定性補正係数を演
算し、安定性余裕代が所定の基準値未満のときは最大安
定性余裕代と現在の安定性余裕代との差分に基づいて安
定性補正係数を演算する構成としたため、最大安定性余
裕代に反映されている燃料性状に応じて燃料噴射量を制
御しつつ、現在の安定性余裕代に反映されている機関の
現在の安定状態をフィードバックすることができ、機関
の安定性を維持することができる。When the stability allowance is equal to or larger than the predetermined reference value, the stability correction coefficient is calculated based on the maximum stability allowance, and when the stability allowance is less than the predetermined reference value, the maximum stability is calculated. The stability correction coefficient is calculated based on the difference between the margin allowance and the current stability margin allowance, so while controlling the fuel injection amount according to the fuel property reflected in the maximum stability margin allowance, Stability of the engine can be fed back, and the stability of the engine can be maintained.
【００７７】さらに、前記低水温時の燃料増量補正係数
を重質燃料に応じて設定し、前記安定性補正係数演算手
段は、０から前記低水温時の燃料増量補正係数の値まで
の範囲内で安定性補正係数を演算する構成としたため、
安定性余裕代の小さい重質燃料の場合に、重質燃料に応
じた燃料増量を行って始動性や運転性を確保することが
できると共に、軽質燃料の場合には、重質燃料に応じて
設定された燃料増量を減量することにより、安定性を維
持しつつ不要な燃料増量を防止して、燃費を向上するこ
とができ、エミッション排出量を低減することができ
る。Further, the fuel increase correction coefficient at the low water temperature is set according to the heavy fuel, and the stability correction coefficient calculating means is within the range from 0 to the value of the fuel increase correction coefficient at the low water temperature. Since the stability correction coefficient is calculated by
In the case of heavy fuel with a small stability margin, it is possible to increase the fuel amount according to the heavy fuel to ensure startability and drivability, and in the case of light fuel, depending on the heavy fuel. By reducing the set fuel increase amount, unnecessary fuel increase can be prevented while maintaining stability, fuel efficiency can be improved, and emission emission amount can be reduced.
【００７８】また、回転数検出手段が機関の各気筒の点
火に応じて出力する回転数信号間の時間を求め、この点
火に応じた回転数信号間の時間の変動を気筒別変化量と
して各気筒毎に演算する手段と、この気筒別変化量を隣
接する気筒間で比較して周期変動を演算する手段と、こ
の周期変動を所定サイクルだけ積算することにより安定
性指標を演算する手段とから安定性指標演算手段を構成
したため、各気筒の点火に応じて出力される回転数信号
間のバラツキや機関の増速，減速に影響されずに、機関
の安定状態を知ることができる。Further, the time between the rotation speed signals output by the rotation speed detecting means in response to the ignition of each cylinder of the engine is obtained, and the fluctuation of the time between the rotation speed signals according to this ignition is set as a variation amount for each cylinder. From the means for calculating for each cylinder, the means for calculating the cycle variation by comparing the variation amount for each cylinder between adjacent cylinders, and the means for calculating the stability index by integrating the cycle variation for a predetermined cycle. Since the stability index calculating means is configured, the stable state of the engine can be known without being affected by the variation between the rotation speed signals output according to the ignition of each cylinder and the acceleration and deceleration of the engine.
【図１】本発明の実施例に係る内燃機関の制御装置の全
体構成を示す構成説明図。FIG. 1 is a configuration explanatory view showing an overall configuration of a control device for an internal combustion engine according to an embodiment of the present invention.
【図２】図１中のコントロールユニットの機能を示す機
能ブロック図。FIG. 2 is a functional block diagram showing functions of a control unit in FIG.
【図３】安定性指標ＴＲＦＳＵＭの演算処理を示すフロ
ーチャート。FIG. 3 is a flowchart showing a calculation process of a stability index TRFSUM.
【図４】安定性補正係数ＫSTB等の演算処理を示すフロ
ーチャート。FIG. 4 is a flowchart showing a calculation process of a stability correction coefficient K STB and the like.
【図５】安定性補正率ＬＳＴＢを求めるための補正率マ
ップ。FIG. 5 is a correction rate map for obtaining a stability correction rate LSTB.
【図６】空燃比設定補正係数ＴＦＢＹＡの演算処理を示
すフローチャート。FIG. 6 is a flowchart showing a calculation process of an air-fuel ratio setting correction coefficient TFBYA.
【図７】燃料噴射量Ｔiの演算処理を示すフローチャー
ト。FIG. 7 is a flowchart showing a calculation process of a fuel injection amount T i .
【図８】本発明の実施例による燃料増量制御を行ったと
きの空燃比及び安定性指標ＴＲＦＳＵＭの変化を従来技
術と比較して示す特性図。FIG. 8 is a characteristic diagram showing changes in the air-fuel ratio and stability index TRFSUM when performing the fuel increase control according to the embodiment of the present invention, as compared with the related art.
【図９】従来技術による始動後増量補正係数ＫASの説明
図。FIG. 9 is an explanatory diagram of a post-starting amount increase correction coefficient K AS according to a conventional technique.
【図１０】水温増量補正係数ＫTWの説明図。FIG. 10 is an explanatory diagram of a water temperature increase correction coefficient K TW .
【図１１】高水温増量補正係数ＫHOTの説明図。FIG. 11 is an explanatory diagram of a high water temperature increase correction coefficient K HOT .
【図１２】ノック制御リタード時増量補正係数ＭＲＫNK
の説明図。FIG. 12: Knock control retard increase correction coefficient MRK NK
Explanatory drawing of.
【図１３】混合比割付補正係数ＫMRの説明図。FIG. 13 is an explanatory diagram of a mixture ratio allocation correction coefficient K MR .
【図１４】電圧補正ＴSの説明図。FIG. 14 is an explanatory diagram of voltage correction T S.
１５…燃料噴射弁 ２０…クランク角センサ（回転数検出手段） ２４…コントロールユニット 15 ... Fuel injection valve 20 ... Crank angle sensor (rotation speed detecting means) 24 ... Control unit
Claims (7)
と、この回転数に基づいて機関の安定状態を示す安定性
指標を演算する安定性指標演算手段と、この安定性指標
と予め設定された安定性許容レベルとを比較し、両者の
差分を安定性余裕代として演算する安定性余裕代演算手
段と、この安定性余裕代に基づいて燃料性状を検出する
燃料性状検出手段と、を備えたことを特徴とする内燃機
関の制御装置。1. A rotation speed detection means for detecting the rotation speed of an engine, a stability index calculation means for calculating a stability index indicating a stable state of the engine based on this rotation speed, and this stability index and preset. A stability margin calculation means for calculating the difference between the two as a stability margin, and a fuel property detection means for detecting a fuel property based on the stability margin. A control device for an internal combustion engine, comprising:
と、この回転数に基づいて機関の安定状態を示す安定性
指標を演算する安定性指標演算手段と、この安定性指標
と予め設定された安定性許容レベルとを比較し、両者の
差分を安定性余裕代として演算する安定性余裕代演算手
段と、この安定性余裕代のうち機関始動後から現在まで
の間で最大値をとる最大安定性余裕代と所定の基準値と
を比較し、最大安定性余裕代が所定の基準値以上のとき
には軽質燃料であると判定し、最大安定性余裕代が所定
の基準値未満のときには重質燃料であると判定する燃料
性状検出手段と、を備えたことを特徴とする内燃機関の
制御装置。2. A rotation speed detection means for detecting the rotation speed of the engine, a stability index calculation means for calculating a stability index indicating a stable state of the engine based on the rotation speed, and this stability index and preset. The stability margin calculation means for calculating the difference between the stability margin level and the calculated stability tolerance level, and the maximum value of the stability margin from the engine start to the present The maximum stability margin is compared with a predetermined reference value, and when the maximum stability margin is equal to or greater than the predetermined reference value, it is determined to be light fuel, and when the maximum stability margin is less than the predetermined reference value, the A control device for an internal combustion engine, comprising: a fuel property detection unit that determines that the fuel is a high quality fuel.
と、この回転数に基づいて機関の安定状態を示す安定性
指標を演算する安定性指標演算手段と、この安定性指標
と予め設定された安定性許容レベルとを比較し、両者の
差分を安定性余裕代として演算する安定性余裕代演算手
段と、予め設定された低水温時の燃料増量補正係数の値
を補正するための安定性補正係数を前記安定性余裕代に
基づいて演算する安定性補正係数演算手段と、この安定
性補正係数と前記低水温時の燃料増量補正係数と機関の
運転条件に応じて定まる基本燃料噴射量とに基づいて燃
料噴射量を演算する燃料噴射量演算手段と、を備えたこ
とを特徴とする内燃機関の制御装置。3. A rotation speed detection means for detecting the rotation speed of the engine, a stability index calculation means for calculating a stability index indicating a stable state of the engine based on this rotation speed, and this stability index and preset. Stability margin allowance calculation means for calculating the difference between the two as a stability margin allowance, and stability for correcting the value of the fuel increase correction coefficient at a preset low water temperature. Stability correction coefficient calculating means for calculating the stability correction coefficient based on the stability margin, and the basic fuel injection amount determined according to the stability correction coefficient, the fuel increase correction coefficient at the low water temperature, and the operating condition of the engine. A control device for an internal combustion engine, comprising: a fuel injection amount calculation means for calculating a fuel injection amount based on
定性余裕代が所定の基準値以上のときには機関始動後か
ら現在までの間で最大値をとる最大安定性余裕代に基づ
いて安定性補正係数を演算し、前記安定性余裕代が前記
所定の基準値未満のときには前記最大安定性余裕代と現
在の安定性余裕代との差分に基づいて安定性補正係数を
演算する構成としたことを特徴とする請求項３に記載の
内燃機関の制御装置。4. The stability correction coefficient calculation means, based on the maximum stability margin, which takes a maximum value from the engine start to the present when the stability margin is equal to or larger than a predetermined reference value. A correction coefficient is calculated, and when the stability margin is less than the predetermined reference value, the stability correction coefficient is calculated based on the difference between the maximum stability margin and the current stability margin. The control device for an internal combustion engine according to claim 3, wherein:
燃料に応じて設定し、前記安定性補正係数演算手段は、
０から前記低水温時の燃料増量補正係数の値までの範囲
内で安定性補正係数を演算する構成としたことを特徴と
する請求項３又は請求項４に記載の内燃機関の制御装
置。5. The fuel increase correction coefficient at the time of low water temperature is set according to heavy fuel, and the stability correction coefficient calculation means is
The control device for an internal combustion engine according to claim 3 or 4, wherein the stability correction coefficient is calculated within a range from 0 to the value of the fuel increase correction coefficient at the low water temperature.
時の燃料増量補正係数により、機関が冷間始動したとき
に燃料噴射量の増量制御を行う内燃機関の制御装置であ
って、 機関の回転数を検出する回転数検出手段と、 この回転数に基づいて機関の回転変動を検出し、この回
転変動に基づいて機関の安定状態を示す安定性指標を演
算する安定性指標演算手段と、 この安定性指標と予め機関の運転条件毎に設定された安
定性許容レベルとを比較し、両者の差分を安定性余裕代
として演算する安定性余裕代演算手段と、 前記低水温時の燃料増量補正係数の値を補正すべく０か
ら該低水温時の燃料増量補正係数の値までの範囲内で可
変である安定性補正係数を、前記安定性余裕代が所定の
基準値以上のときには機関始動後から現在までの間で最
大値をとる最大安定性余裕代に基づいて演算すると共に
前記安定性余裕代が所定の基準値未満の場合のときには
前記最大安定性余裕代と現在の安定性余裕代との差分に
基づいて演算する安定性補正係数演算手段と、 この安定性補正係数と前記低水温時の燃料増量補正係数
と機関の運転条件に応じて定まる基本燃料噴射量とに基
づき、前記安定性補正係数の値が大きくなるにつれて燃
料噴射量の値が小さくなるように燃料噴射量を演算する
燃料噴射量演算手段と、 を備えたことを特徴とする内燃機関の制御装置。6. A control device for an internal combustion engine, which performs an increase control of a fuel injection amount when the engine is cold-started by a fuel increase correction coefficient at a low water temperature preset according to heavy fuel, Rotational speed detection means for detecting the rotational speed of the engine, and stability index calculation means for detecting the rotational fluctuation of the engine based on this rotational speed and calculating a stability index indicating the stable state of the engine based on this rotational fluctuation. And a stability margin calculation means for calculating a difference between the stability index and the stability tolerance level set in advance for each engine operating condition as a stability margin, and A stability correction coefficient that is variable within a range from 0 to the value of the fuel increase correction coefficient at the time of low water temperature is used to correct the value of the fuel increase correction coefficient when the stability margin is equal to or larger than a predetermined reference value. Maximum from engine start to present When the stability margin is less than a predetermined reference value, the stability is calculated based on the difference between the maximum stability margin and the current stability margin. Based on the stability correction coefficient, the stability correction coefficient, the fuel increase correction coefficient at the low water temperature, and the basic fuel injection amount determined according to the operating condition of the engine, as the value of the stability correction coefficient increases. A control device for an internal combustion engine, comprising: a fuel injection amount calculation means for calculating a fuel injection amount so that the value of the fuel injection amount becomes small.
検出手段が機関の各気筒の点火に応じて出力する回転数
信号間の時間を求め、この点火に応じた回転数信号間の
時間の変動を気筒別変化量として各気筒毎に演算する手
段と、この気筒別変化量を隣接する気筒間で比較して周
期変動を演算する手段と、この周期変動を所定サイクル
だけ積算することにより安定性指標を演算する手段と、
から構成したことを特徴とする請求項１〜６のいずれか
に記載の内燃機関の制御装置。7. The stability index calculation means obtains a time between rotation speed signals output by the rotation speed detection means according to ignition of each cylinder of the engine, and a time between rotation speed signals according to the ignition. By calculating the fluctuation of each cylinder as a cylinder-by-cylinder change amount for each cylinder, by comparing the cylinder-by-cylinder change amount between adjacent cylinders and calculating a cycle fluctuation, and by integrating the cycle fluctuation for a predetermined cycle, Means for calculating a stability index,
The control device for an internal combustion engine according to any one of claims 1 to 6, which is configured by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22290694A JP3591001B2 (en) | 1994-09-19 | 1994-09-19 | Control device for internal combustion engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22290694A JP3591001B2 (en) | 1994-09-19 | 1994-09-19 | Control device for internal combustion engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0886237A true JPH0886237A (en) | 1996-04-02 |
| JP3591001B2 JP3591001B2 (en) | 2004-11-17 |
Family
ID=16789724
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22290694A Expired - Fee Related JP3591001B2 (en) | 1994-09-19 | 1994-09-19 | Control device for internal combustion engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3591001B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007071111A (en) * | 2005-09-07 | 2007-03-22 | Toyota Motor Corp | Fuel property determining device for internal combustion engine |
| JP2007239637A (en) * | 2006-03-09 | 2007-09-20 | Toyota Motor Corp | Fuel injection control device for internal combustion engine |
| KR100802706B1 (en) * | 2006-11-16 | 2008-02-12 | 현대자동차주식회사 | Managing method of exhaust for noxious gas |
| JP2008291757A (en) * | 2007-05-25 | 2008-12-04 | Hitachi Ltd | Fuel control device of internal combustion engine |
| JP2008309117A (en) * | 2007-06-15 | 2008-12-25 | Toyota Motor Corp | Control device of internal combustion engine |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4777919B2 (en) * | 2007-02-16 | 2011-09-21 | 日立オートモティブシステムズ株式会社 | Fuel control device for internal combustion engine |
-
1994
- 1994-09-19 JP JP22290694A patent/JP3591001B2/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007071111A (en) * | 2005-09-07 | 2007-03-22 | Toyota Motor Corp | Fuel property determining device for internal combustion engine |
| JP2007239637A (en) * | 2006-03-09 | 2007-09-20 | Toyota Motor Corp | Fuel injection control device for internal combustion engine |
| KR100802706B1 (en) * | 2006-11-16 | 2008-02-12 | 현대자동차주식회사 | Managing method of exhaust for noxious gas |
| JP2008291757A (en) * | 2007-05-25 | 2008-12-04 | Hitachi Ltd | Fuel control device of internal combustion engine |
| JP2008309117A (en) * | 2007-06-15 | 2008-12-25 | Toyota Motor Corp | Control device of internal combustion engine |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3591001B2 (en) | 2004-11-17 |
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