JPS6217701B2 - - Google Patents
Info
- Publication number
- JPS6217701B2 JPS6217701B2 JP54109198A JP10919879A JPS6217701B2 JP S6217701 B2 JPS6217701 B2 JP S6217701B2 JP 54109198 A JP54109198 A JP 54109198A JP 10919879 A JP10919879 A JP 10919879A JP S6217701 B2 JPS6217701 B2 JP S6217701B2
- Authority
- JP
- Japan
- Prior art keywords
- air
- fuel ratio
- control
- value
- exhaust sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000000446 fuel Substances 0.000 claims description 52
- 239000000203 mixture Substances 0.000 claims description 15
- 238000002485 combustion reaction Methods 0.000 claims description 9
- 230000007423 decrease Effects 0.000 claims description 7
- 238000010586 diagram Methods 0.000 description 9
- 239000007789 gas Substances 0.000 description 7
- 230000008859 change Effects 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 4
- 230000007257 malfunction Effects 0.000 description 4
- 238000000746 purification Methods 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 230000007935 neutral effect Effects 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000007562 laser obscuration time method Methods 0.000 description 1
- 230000029058 respiratory gaseous exchange Effects 0.000 description 1
Landscapes
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
- Safety Devices In Control Systems (AREA)
- Measuring Oxygen Concentration In Cells (AREA)
Description
【発明の詳細な説明】
本発明は内燃機関の空燃比制御装置に関し、特
にクローズドループ制御停止の判定機能に関する
ものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air-fuel ratio control device for an internal combustion engine, and particularly relates to a closed-loop control stop determination function.
最近、機関の排気ガス成分濃度に基づいて混合
気の空燃比を検出し、空燃比が一定値になるよう
に帰還制御する空燃比制御装置が開発されてい
る。 Recently, an air-fuel ratio control device has been developed that detects the air-fuel ratio of an air-fuel mixture based on the concentration of exhaust gas components of an engine and performs feedback control so that the air-fuel ratio becomes a constant value.
排気ガス成分濃度を検出する排気センサとして
一般に用いられているジルコニア酸素濃度計の特
性は第１図に示すようになる。なお第１図におい
て、λ＝１の点が理論空燃比の点を示す。 The characteristics of a zirconia oxygen concentration meter, which is generally used as an exhaust sensor for detecting the concentration of exhaust gas components, are shown in FIG. In FIG. 1, the point λ=1 indicates the stoichiometric air-fuel ratio.
第１図から判るように、出力電圧V0が基準値
Ｖsより大きいときは空燃比が理論空燃比より小
さく（混合気が過濃）、V0がＶsより小さいときは
空燃比が理論空燃比より大きい（混合気が希薄）
ことを示す。したがつて出力電圧V0と基準値Ｖs
との大小関係を比較することによつて空燃比の状
態を判別し、混合気が過濃なときには燃料を減少
させ、希薄なときに増加させるように帰還制御す
れば、空燃比を一定の値、例えば理論空燃比に維
持するように制御することが出来る。 As can be seen from Figure 1, when the output voltage V 0 is greater than the reference value V s , the air-fuel ratio is smaller than the stoichiometric air-fuel ratio (the air-fuel mixture is too rich), and when V 0 is smaller than V s , the air-fuel ratio is less than the stoichiometric air-fuel ratio. Greater than the air-fuel ratio (lean mixture)
Show that. Therefore, the output voltage V 0 and the reference value V s
The state of the air-fuel ratio can be determined by comparing the magnitude relationship with For example, the air-fuel ratio can be controlled to be maintained at the stoichiometric air-fuel ratio.
上記のごとき空燃比制御装置に用いる排気セン
サは、通常、温度によつて特性が変化する。例え
ば前記のジルコニア酸素濃度計の場合、その電気
的等価回路は、第２図に示すごとく、酸素濃度に
応じて起電力ｅの変化する電池と、センサの温度
に応じて抵抗値ρの変化する内部抵抗との直列回
路で表わされる。そして内部抵抗ρの値は第３図
に示すような温度特性を有するため、低温時には
内部抵抗ρが大きくなつて起電力ｅを有効に取り
出すことが困難になる。そのため排気センサの低
温時は空燃比制御装置をオープンループ制御（通
常、一定の状態に保持する）させ、排気センサが
十分動作出来る温度になつてからクローズドルー
プ制御（帰還制御）させる必要がある。 The characteristics of the exhaust sensor used in the above air-fuel ratio control device usually change depending on the temperature. For example, in the case of the zirconia oxygen concentration meter mentioned above, its electrical equivalent circuit consists of a battery whose electromotive force e changes according to the oxygen concentration, and a resistance value ρ which changes according to the sensor temperature, as shown in Figure 2. It is expressed as a series circuit with an internal resistance. Since the value of the internal resistance ρ has a temperature characteristic as shown in FIG. 3, the internal resistance ρ increases at low temperatures, making it difficult to extract the electromotive force e effectively. Therefore, when the temperature of the exhaust sensor is low, the air-fuel ratio control device must be subjected to open-loop control (usually kept in a constant state), and then closed-loop control (feedback control) must be performed after the exhaust sensor reaches a temperature at which it can operate sufficiently.
排気センサの温度を測定する方法としては、排
気センサに外部から電流を流し、温度変化に応じ
て生ずる内部抵抗の変化に伴う電圧変化によつて
測定する方法がある。 As a method for measuring the temperature of the exhaust sensor, there is a method in which a current is applied to the exhaust sensor from the outside and the temperature is measured by a voltage change accompanying a change in internal resistance that occurs in response to a temperature change.
すなわち、排気センサに外部から一定の電流ｉ
を流すと、排気センサの出力電圧V0は、
V0＝ｅ＋ρｉ ………(1)
となる。上記(1)式において、温度の低下につれて
ρが上昇するとV0も上昇し、混合気の過濃・希
薄の状態にかかわりなく、常にV0の値が基準値
Ｖs以上になる。したがつてV0＞Ｖsの状態が所定
時間以上継続した場合にオープンループ制御に切
換えれば良い。しかし上記の方式においては、機
関の作動状態（例えば加減速時等）によつて排気
センサ温度が正常でもV0＞Ｖsの状態がかなり長
く続く場合があることを考慮して、上記の所定時
間の値をかなり長く（例えば６秒〜８秒程度）設
定しなければならず、そのためオープンループ制
御に切換る直前に、かなり長い間、混合気が薄く
なるように制御されるので、制御の移行時に機関
回転数が低下して回転が不安定になり、特にその
状態で走行を開始した場合には、いわゆる息つき
状態を生じて運転性が低下するおそれがある。 In other words, a constant current i is applied to the exhaust sensor from the outside.
, the output voltage V 0 of the exhaust sensor becomes V 0 =e+ρi (1). In the above equation (1), when ρ increases as the temperature decreases, V 0 also increases, and the value of V 0 is always equal to or higher than the reference value V s regardless of whether the air-fuel mixture is rich or lean. Therefore, if the state of V 0 >V s continues for a predetermined period of time or more, it is sufficient to switch to open loop control. However, in the above method, the above predetermined value is taken into account that the state of V 0 > V s may continue for quite a long time even if the exhaust sensor temperature is normal depending on the operating state of the engine (for example, during acceleration/deceleration, etc.). The time value must be set quite long (for example, about 6 to 8 seconds), so the mixture is controlled to be lean for quite a long time just before switching to open-loop control, so the control At the time of transition, the engine speed decreases and the rotation becomes unstable, and especially if the vehicle starts traveling in this state, there is a risk that a so-called breathing condition may occur and drivability may deteriorate.
本発明は上記の問題に鑑みてなされたものであ
り、排気センサ出力の極小値が所定回数以上連続
して所定値以上になつた場合にクローズドループ
制御を停止させてオープンループ制御を行なわせ
るように構成することにより、制御を簡略化し、
制御切換時の安定性を向上させ、かつ制御の誤つ
た切換えを防止することの出来る空燃比制御装置
を提供することを目的とする
また本発明は、排気センサ出力の極小値が所定
回数以上連続して所定値以上になり、かつ制御周
期（リツチとリーンの繰返し周期）が、排気セン
サの温度が正常動作可能温度以下に低下した場合
の制御周期に相当する第１の所定時間以上のとき
にクローズドループ制御を停止させるように構成
することにより、排気センサ劣化時の誤動作を防
止した空燃比制御装置を提供することを目的とす
る。 The present invention has been made in view of the above-mentioned problems, and is designed to stop closed-loop control and perform open-loop control when the minimum value of the exhaust sensor output exceeds a predetermined value consecutively for a predetermined number of times or more. By configuring
It is an object of the present invention to provide an air-fuel ratio control device that can improve stability during control switching and prevent erroneous control switching. is equal to or greater than a predetermined value, and the control cycle (rich and lean repetition cycle) is equal to or greater than the first predetermined time corresponding to the control cycle when the temperature of the exhaust sensor falls below the normal operating temperature. An object of the present invention is to provide an air-fuel ratio control device that prevents malfunctions when an exhaust sensor deteriorates by being configured to stop closed-loop control.
更に本発明は、上記の機能の他に、制御周期が
第２の所定時間以上になつたときにもクローズド
ループ制御を停止させるように構成することによ
り、排気センサやハーネスの断線、短絡等による
誤動作をも防止した空燃比制御装置を提供するこ
とを目的とする。 Furthermore, in addition to the above-mentioned functions, the present invention is configured to stop the closed loop control even when the control cycle exceeds a second predetermined time, thereby preventing disconnection or short circuit of the exhaust sensor or harness. It is an object of the present invention to provide an air-fuel ratio control device that also prevents malfunctions.
以下図面に基づいて本発明を詳細に説明する。 The present invention will be explained in detail below based on the drawings.
第４図は本発明を適用する空燃比制御装置の一
例のブロツク図である。 FIG. 4 is a block diagram of an example of an air-fuel ratio control device to which the present invention is applied.
第４図において、１は燃焼室、２は吸気管、３
は絞り弁、４は絞り弁開度を検出する開度センサ
５は吸入空気量を検出する吸気量センサ、６は排
気管、７は排気センサ、８は例えば三元触媒等の
排気浄化装置、９はウオータジヤケツト内の冷却
水温を検出する水温センサ、１０は変速機のニユ
ートラル位置を検出するニユートラルスイツチ、
１１は例えば変速機の駆動軸の回転から車速を検
出する車速センサ、１２は機関回転数を検出する
回転センサであり、例えばクランク軸の単位角度
ごとにパルスを出力するクランク角センサを用い
る。また１３は演算装置であり、例えば中央演算
回路（CPU）、ROM、RAM及び入出力インタフ
エース等からなるマイクロコンピユータで構成さ
れている。また１４は燃料噴射弁である。 In Fig. 4, 1 is a combustion chamber, 2 is an intake pipe, and 3 is a combustion chamber.
4 is a throttle valve; 4 is an opening sensor 5 for detecting the intake air amount; 6 is an exhaust pipe; 7 is an exhaust sensor; 8 is an exhaust purification device such as a three-way catalyst; 9 is a water temperature sensor that detects the temperature of the cooling water in the water jacket; 10 is a neutral switch that detects the neutral position of the transmission;
Numeral 11 is a vehicle speed sensor that detects the vehicle speed from the rotation of the drive shaft of the transmission, for example, and 12 is a rotation sensor that detects the engine rotational speed, such as a crank angle sensor that outputs a pulse for each unit angle of the crankshaft. Reference numeral 13 denotes an arithmetic unit, which is composed of, for example, a microcomputer including a central processing circuit (CPU), ROM, RAM, input/output interface, and the like. Further, 14 is a fuel injection valve.
次に動作について説明する。 Next, the operation will be explained.
各種のセンサ４，５，７，９，１０，１１及び
１２の信号は、演算装置１３に与えられる。演算
装置１３は上記の各信号に基づいて、そのときの
運転状態に適合した燃料供給量を算出する。その
算出結果に応じて燃料噴射弁１４が作動し、例え
ば機機関１回転毎に１回噴射を行なつて上記の算
出された燃料供給量に対応した量の燃料を噴射す
る。 Signals from the various sensors 4, 5, 7, 9, 10, 11, and 12 are given to the arithmetic unit 13. The arithmetic unit 13 calculates the amount of fuel to be supplied that is suitable for the current operating state based on each of the above-mentioned signals. The fuel injection valve 14 operates according to the calculation result, and injects fuel in an amount corresponding to the calculated fuel supply amount, for example, once per rotation of the machine engine.
噴射された燃料は、吸気管２を介して流入して
くる空気と混合して混合気となり、燃焼室１に入
つて燃焼する。 The injected fuel mixes with air flowing in through the intake pipe 2 to form an air-fuel mixture, which enters the combustion chamber 1 and is combusted.
燃焼後の排気ガスは排気管６及び排気浄化装置
８を介して排出される。 The exhaust gas after combustion is discharged via the exhaust pipe 6 and the exhaust purification device 8.
排気浄化装置８が三元触媒の場合には、排気ガ
ス中のHC及びCOは酸化され、NOXは還元されて
浄化されるが、この際の転換効率は混合気の空燃
比が理論空燃比であつた場合に最大となる。 When the exhaust purification device 8 is a three-way catalyst, HC and CO in the exhaust gas are oxidized and NO It is maximum when .
排気センサ７は排気ガス中の成分濃度を検出す
るものであり、この信号に応じて空燃比帰還制御
が行なわれる。 The exhaust sensor 7 detects the concentration of components in the exhaust gas, and air-fuel ratio feedback control is performed in response to this signal.
次に第５図は排気センサ出力電圧の温度特性図
であり、イは電流流し込みを行なわない場合、ロ
は低電圧を印加して小電流の流し込みを行なつた
場合、ハは高電圧を印加して大電流の流し込みを
行なつた場合を示す。また図において、ＶRは混
合気過濃（リツチ）時のV0の値、ＶLは混合気希
薄（リーン）時のV0の値を示す。 Next, Figure 5 is a temperature characteristic diagram of the exhaust sensor output voltage, where A is when no current is injected, B is when a low voltage is applied and a small current is injected, and C is when a high voltage is applied. This shows the case where a large current is injected. In the figure, V R indicates the value of V 0 when the mixture is rich, and V L indicates the value of V 0 when the mixture is lean.
第５図から判るように、イ，ロ，ハのいずれに
おいても、温度が低下するにつれてＶLは一旦上
昇する。したがつて正常動作温度の下限値Ｔに対
応した値ＶSLを定めておき、V0の極小値すなわ
ちＶLがＶSL以上になつたときにクローズドルー
プ制御を停止させれば良い。 As can be seen from FIG. 5, in all cases A, B, and C, V L increases once as the temperature decreases. Therefore, a value V SL corresponding to the lower limit value T of the normal operating temperature may be determined, and the closed loop control may be stopped when the minimum value of V 0 , that is, V L becomes equal to or higher than V SL .
ただし、イの電流流し込みをしない場合には、
低温時におけるＶLの特性が多少不安定になるの
で、実用的にはロ又はハに示すように電流流し込
みを行なう方が望ましい。 However, if the current is not injected in (a),
Since the characteristics of V L become somewhat unstable at low temperatures, it is practically preferable to inject the current as shown in (b) or (c).
なお、ＶLがＶSL以上になつたとき直ちにオー
プンループ制御に切換えるように構成すると、低
回転時の排気ガス流の乱れ等によつてＶLの値が
一時的に上昇したときにもオープンループ制御に
切換つてしまうおそれがある。それを避けるに
は、所定回数（例えば３回）以上連続してＶLが
ＶSL以上になつた場合に、オープンループ制御に
切換えるように構成する。 Note that if the configuration is configured to switch to open-loop control immediately when V L exceeds V SL , the open-loop control will be activated even when the value of V L temporarily increases due to turbulence in the exhaust gas flow at low rotation speeds. There is a risk of switching to loop control. In order to avoid this, the system is configured to switch to open loop control when V L becomes equal to or higher than V SL for a predetermined number of times (for example, three times) or more consecutively.
また排気センサが劣化してくると、V0の振巾
が小さくなり、ＶLの値が上昇してくるので、こ
の場合も誤動作するおそれがある。しかし上記の
ごとく排気センサが劣化してＶLの値が上昇した
場合には制御周期すなわちリツチ（過濃）とリー
ン（希薄）の繰返し周期の変化には殆んど影響が
ないのに対し、排気センサの温度が低下した場合
には前者に比較して制御周期が長くなる。したが
つてＶLが所定回数以上連続してＶSL以上にな
り、かつ制御周期が所定値（例えば５秒）以上の
ときオープンループ制御に切換えるように構成す
れば良い。 Further, as the exhaust sensor deteriorates, the amplitude of V 0 becomes smaller and the value of V L increases, so there is also a risk of malfunction in this case. However, as mentioned above, when the exhaust sensor deteriorates and the value of V L increases, there is almost no effect on the control cycle, that is, the change in the rich and lean repetition cycle. When the temperature of the exhaust sensor decreases, the control cycle becomes longer than in the former case. Therefore, the system may be configured to switch to open-loop control when V L becomes equal to or greater than V SL for a predetermined number of consecutive times or more and the control period is equal to or greater than a predetermined value (for example, 5 seconds).
また排気センサやハーネスが短絡又は断線した
場合には、V0の値が０又は一定値になつてしま
う。そのため上記のごとくＶLの値が所定回数以
上連続してＶSL以上になつたときにオープンルー
プ制御に切換えるようにしておくと、短絡又は断
線時又は急激な排温低下によつて極小値が所定回
数以上連続してＶSL以上の状態にならない場合に
はオープンループ制御に切換らなくなり、混合気
が大巾に偏つた値になるおそれがある。したがつ
て制御周期が所定値（例えば８秒）以上になつた
場合には、前記の条件とは独立にオープンループ
制御に切換えるように構成する。 Further, if the exhaust sensor or the harness is short-circuited or disconnected, the value of V 0 becomes 0 or a constant value. Therefore, if you switch to open-loop control when the value of V L exceeds V SL for a predetermined number of times or more consecutively as described above, the minimum value will be reduced due to a short circuit or disconnection, or a sudden drop in exhaust temperature. If the state does not reach V SL or higher continuously for a predetermined number of times or more, the open-loop control will not be performed, and there is a risk that the air-fuel mixture will have a significantly biased value. Therefore, when the control period exceeds a predetermined value (for example, 8 seconds), the control is configured to switch to open loop control independently of the above conditions.
第６図は本発明の一実施例のフローチヤートで
あり、前記の条件を全て含んだ場合を示す。 FIG. 6 is a flowchart of an embodiment of the present invention, and shows a case in which all of the above conditions are included.
第６図において、まずブロツク３１でそのとき
の混合気がリツチかリーンかを判定する。 In FIG. 6, first, in block 31, it is determined whether the air-fuel mixture at that time is rich or lean.
リーンの場合はブロツク３２へ行つて前回の演
算のときもリーンであつたか否かを判定し、前回
はリツチであつた場合、すなわち今回リーンに切
換つた場合には、比例制御分を計算すると共にス
ライスレベル（基準値ＶS）をリーン時の値
480mVに切換える。また前回もリーンであつた
場合、すなわちリーン状態が継続している場合に
は積分制御分を計算する。またリツチ・リーンフ
ラグは、“１”がリツチ、“０”がリーンを示す。 If lean, go to block 32 to determine whether the previous calculation was also lean. If it was rich last time, that is, if it is switched to lean this time, the proportional control portion is calculated and The slice level (reference value V S ) is the value when lean.
Switch to 480mV. Furthermore, if the lean condition was also present last time, that is, if the lean condition continues, the integral control amount is calculated. Furthermore, for the rich/lean flag, "1" indicates rich and "0" indicates lean.
また制御周期を計測するタイマをクリアする。 Also clears the timer that measures the control cycle.
次にブロツク３５ではV0を前回までの極小値
と比較し、V0が前回までの極小値より小さいと
きはそのときのV0を新しい極小値として記憶す
る。その後ブロツク４７で制御周期が８秒以上か
チエツクしNOの場合は計算結果を出力する。 Next, in block 35, V 0 is compared with the previous minimum value, and if V 0 is smaller than the previous minimum value, the current V 0 is stored as a new minimum value. Thereafter, in block 47, it is checked whether the control period is 8 seconds or more, and if NO, the calculation result is output.
一方、ブロツク３１でリツチであつた場合は、
ブロツク３８〜４０で、リーンの場合と同様に、
今回リツチに切換つた場合は比例制御分を計算す
ると共にスライスレベルをリツチ時の値430mV
に切換え、またリツチが継続している場合は積分
制御分の計算を行なう。 On the other hand, if block 31 is rich,
In blocks 38-40, as in the lean case,
If you switch to rich this time, calculate the proportional control and set the slice level to 430mV, which is the value when rich.
If the richness continues, the integral control portion is calculated.
次にブロツク４１では、極小値がＶSL以上か否
かを判別し、YESの場合はブロツク４２で極小
値をクリア（本実施例では1.0Vにする）すると
共にカウンタを１だけ加算する。そしてブロツク
４４でカウンタの計数値が３以上か否か、すなわ
ち３回以上連続して極小値がＶSL以上であつたか
否かを判別し、YESの場合はブロツク４５でタ
イマが５秒以上か否か、すなわち制御周期が５秒
以上か否かを判別する。ブロツク４５がYESの
場合は、ブロツク４６でカウンタをクリアしたの
ち、ブロツク４８で補正係数αを１に固定してオ
ープンループ制御とする。 Next, in block 41, it is determined whether or not the minimum value is greater than or equal to VSL . If YES, in block 42, the minimum value is cleared (to 1.0V in this embodiment) and the counter is incremented by 1. Then, in block 44, it is determined whether the counted value of the counter is 3 or more, that is, whether the local minimum value has been greater than or equal to V SL three or more times in a row.If YES, then in block 45, it is determined whether the timer is 5 seconds or more. It is determined whether or not, that is, whether the control period is 5 seconds or more. If block 45 is YES, block 46 clears the counter, and block 48 fixes the correction coefficient α to 1 to perform open loop control.
なおブロツク４１，４４及び４５がそれぞれ
NOの場合はブロツク４７に行き、タイマが８秒
以上か否か、すなわち制御周期が８秒以上か否か
を判別し、YESの場合にはブロツク４８に行つ
てオープンループ制御とする。なおブロツク３
５，３６からもブロツク４７へ行き、リーンの場
合でも制御周期が８秒以上になるとオープンルー
プ制御とする。 Furthermore, blocks 41, 44 and 45 are respectively
If NO, the process goes to block 47, where it is determined whether the timer is longer than 8 seconds, that is, whether the control cycle is longer than 8 seconds, and if YES, the process goes to block 48, where open loop control is performed. Furthermore, block 3
Steps 5 and 36 also lead to block 47, and even in the case of lean, if the control period is 8 seconds or more, open loop control is performed.
第６図では、V0がリツチを示しているとき、
すなわちリーン側に制御しているときにオープン
ループに切換えるように構成しているが、逆にリ
ツチ側に制御しているときに切換えるように構成
することも出来る。 In Figure 6, when V 0 indicates richness,
That is, although the configuration is such that the switch is made to the open loop when the control is on the lean side, it is also possible to switch to the open loop when the control is on the rich side.
次に第７図は上記の制御における信号波形図で
あり、イは温度が低下した場合、ロは排気センサ
又はハーネスが短絡した場合、ハは断線した場合
を示す。 Next, FIG. 7 is a signal waveform diagram in the above control, where A shows a case where the temperature decreases, B shows a case where the exhaust sensor or harness is short-circuited, and C shows a case where the wire is disconnected.
まずイにおいて、V0の極小値が３回連続して
ＶSL以上になり、かつ制御周期τ１が５秒以上に
なつた時点t1においてクローズドループ制御が停
止され、オープンループ制御が開始される。ただ
し補正係数αの値は瞬間的にα＝１に変更するよ
りも、図示のごとく、積分特性で次第に１に近づ
けた方が安定性が良くなる。 First, in A, at time t 1 when the minimum value of V 0 becomes equal to or higher than V SL three times in a row and the control period τ 1 becomes 5 seconds or more, closed-loop control is stopped and open-loop control is started. Ru. However, rather than instantaneously changing the value of the correction coefficient α to α=1, as shown in the figure, it is better to gradually bring the value of the correction coefficient α closer to 1 using the integral characteristic for better stability.
次にロは、時点t2において排気センサが短絡し
た場合であり、制御周期τ２が８秒以上になつた
時点t3でクローズドループ制御が停止させられ
る。 Next, B is a case where the exhaust sensor is short-circuited at time t2 , and the closed loop control is stopped at time t3 when the control period τ2 becomes 8 seconds or more.
次にハは、時点t4で排気センサが断線した場合
であり、制御周期τ３が８秒以上になつた時点t5
でクローズドループ制御が停止させられる。 Next, C is a case where the exhaust sensor is disconnected at time t 4 , and at time t 5 when the control period τ 3 becomes 8 seconds or more.
Closed loop control is stopped.
なおハの波形は、300mVの一定電圧を印加し
て電流流し込みを行なつている場合の波形を示
す。 Note that the waveform C shows a waveform when a constant voltage of 300 mV is applied and current is poured.
以上説明したごとく本発明によれば、V0の極
小値が所定回数以上連続して所定値以上になつた
ときクローズドループ制御を停止させるように構
成したことにより、制御が簡略化されると共に、
制御切換え時の混合気の偏りをなくすことが出来
るので機関の安定性を向上させることが出来、ま
た低回転時の排気ガスの乱れによつて極小値が一
時的に上昇したときに誤つてオープンループ制御
に切換えるおそれがなくなる。 As explained above, according to the present invention, the closed-loop control is stopped when the minimum value of V 0 reaches a predetermined value or more consecutively for a predetermined number of times or more, thereby simplifying the control.
It is possible to improve the stability of the engine by eliminating imbalance in the air-fuel mixture when switching control, and it also prevents accidental opening when the minimum value temporarily rises due to turbulence in the exhaust gas at low rotation speeds. There is no risk of switching to loop control.
また、極小値が所定回数以上連続して所定値以
上であり、かつ制御周期が所定時間以上のときク
ローズドループ制御を停止させることにより、排
気センサ劣化時の誤動作を防止することが出来
る。なお制御周期すなわちリツチとリーンとを繰
返す一周期の長さで判別しているので、従来のご
とく、リツチ又はリーンの一方に偏つた時間で判
別するもののように、混合気が一方に大きく偏る
おそれがない。 Further, by stopping the closed loop control when the local minimum value is continuously equal to or greater than a predetermined value for a predetermined number of times or more and the control period is longer than a predetermined time, it is possible to prevent malfunctions when the exhaust sensor deteriorates. Furthermore, since the control cycle is determined based on the length of one cycle in which rich and lean are repeated, there is a risk that the air-fuel mixture will be greatly biased to one side, unlike the conventional method, which discriminates based on the time when rich or lean is biased. There is no.
また上記の機能に、制御周期が所定時間以上の
ときクローズドループ制御を停止させる機能を組
合せることにより、排気センサの断線、短絡時に
も確実にクローズドループ制御を停止させること
が出来る。 Furthermore, by combining the above function with a function that stops the closed loop control when the control cycle is longer than a predetermined time, the closed loop control can be reliably stopped even when the exhaust sensor is disconnected or shorted.
第１図は排気センサの出力特性図、第２図は排
気センサの等価回路図、第３図は内部抵抗の温度
特性図、第４図は本発明を適用する空燃比制御装
置の一例のブロツク図、第５図は排気センサ出力
の温度特性図、第６図は本発明の一実施例のフロ
ーチヤート、第７図は本発明の制御における信号
波形図である。
符号の説明 １……燃焼室、２……吸気管、３
……絞り弁、４……開度センサ、５……吸気量セ
ンサ、６……排気管、７……排気センサ、８……
排気浄化装置、９……水温センサ、１０……ニユ
ートラルスイツチ、１１……車速センサ、１２…
…回転センサ、１３……演算装置、１４……燃料
噴射弁、１５……排気センサ。
Fig. 1 is an output characteristic diagram of the exhaust sensor, Fig. 2 is an equivalent circuit diagram of the exhaust sensor, Fig. 3 is a temperature characteristic diagram of internal resistance, and Fig. 4 is a block diagram of an example of an air-fuel ratio control device to which the present invention is applied. 5 is a temperature characteristic diagram of the exhaust sensor output, FIG. 6 is a flowchart of an embodiment of the present invention, and FIG. 7 is a signal waveform diagram in control of the present invention. Explanation of symbols 1...Combustion chamber, 2...Intake pipe, 3
... Throttle valve, 4 ... Opening sensor, 5 ... Intake amount sensor, 6 ... Exhaust pipe, 7 ... Exhaust sensor, 8 ...
Exhaust purification device, 9...Water temperature sensor, 10...Neutral switch, 11...Vehicle speed sensor, 12...
... Rotation sensor, 13 ... Arithmetic device, 14 ... Fuel injection valve, 15 ... Exhaust sensor.
Claims (1)
センサの出力と基準値との偏差に応じて燃料供給
量を帰還制御することにより、混合気の空燃比を
所定値に保つように制御する空燃比制御装置にお
いて、排気センサの出力電圧の極小値が所定回数
以上連続して所定値以上になつた場合に帰還制御
を停止させる手段を備えた空燃比制御装置。 ２ 内燃機関の排気ガス成分濃度を検出する排気
センサの出力と基準値との偏差に応じて燃料供給
量を帰還制御することにより、混合気の空燃比を
所定値に保つように制御する空燃比制御装置にお
いて、排気センサの出力電圧の極小値が所定回数
以上連続して所定値以上になり、かつ制御周期
が、排気センサの温度が正常動作可能温度以下に
低下した場合の制御周期に相当する第１の所定時
間以上になつた場合に帰還制御を停止させる手段
を備えた空燃比制御装置。 ３ 内燃機関の排気ガス成分濃度を検出する排気
センサの出力と基準値との偏差に応じて燃料供給
量を帰還制御することにより、混合気の空燃比を
所定値に保つように制御する空燃比制御装置にお
いて、排気センサの出力電圧の極小値が所定回数
以上連続して所定値以上になり、かつ制御周期
が、排気センサの温度が正常動作可能温度以下に
低下した場合の制御周期に相当する第１の所定時
間以上になつた場合に帰還制御を停止させる手段
と、制御周期が上記第１の所定時間より長い第２
の所定時間以上になつた場合に帰還制御を停止さ
せる手段とを備えた空燃比制御装置。[Claims] 1. Maintaining the air-fuel ratio of the air-fuel mixture at a predetermined value by feedback-controlling the fuel supply amount according to the deviation between the output of an exhaust sensor that detects the concentration of exhaust gas components of the internal combustion engine and a reference value. An air-fuel ratio control device that controls the air-fuel ratio as described above, the air-fuel ratio control device comprising means for stopping feedback control when the minimum value of the output voltage of the exhaust sensor exceeds a predetermined value consecutively for a predetermined number of times or more. 2. An air-fuel ratio that controls the air-fuel ratio of the air-fuel mixture to a predetermined value by feedback-controlling the fuel supply amount according to the deviation between the output of an exhaust sensor that detects the concentration of exhaust gas components of the internal combustion engine and a reference value. In the control device, the minimum value of the output voltage of the exhaust sensor is continuously equal to or higher than a predetermined value for a predetermined number of times or more, and the control cycle corresponds to a control cycle when the temperature of the exhaust sensor decreases to a normal operating temperature or lower. An air-fuel ratio control device comprising means for stopping feedback control when a first predetermined time has elapsed. 3 An air-fuel ratio that controls the air-fuel ratio of the air-fuel mixture to a predetermined value by feedback-controlling the fuel supply amount according to the deviation between the output of an exhaust sensor that detects the concentration of exhaust gas components of the internal combustion engine and a reference value. In the control device, the minimum value of the output voltage of the exhaust sensor is continuously equal to or higher than a predetermined value for a predetermined number of times or more, and the control cycle corresponds to a control cycle when the temperature of the exhaust sensor decreases to a normal operating temperature or lower. means for stopping the feedback control when the first predetermined time is exceeded;
an air-fuel ratio control device comprising means for stopping feedback control when a predetermined period of time has elapsed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10919879A JPS5633539A (en) | 1979-08-29 | 1979-08-29 | Air fuel ratio controller |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10919879A JPS5633539A (en) | 1979-08-29 | 1979-08-29 | Air fuel ratio controller |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5633539A JPS5633539A (en) | 1981-04-04 |
| JPS6217701B2 true JPS6217701B2 (en) | 1987-04-18 |
Family
ID=14504096
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10919879A Granted JPS5633539A (en) | 1979-08-29 | 1979-08-29 | Air fuel ratio controller |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5633539A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5870036A (en) * | 1981-10-23 | 1983-04-26 | Toyota Motor Corp | Apparatus for controlling air-fuel ratio of internal-combustion engine |
| JPS60184941A (en) * | 1984-03-02 | 1985-09-20 | Suzuki Motor Co Ltd | Air/fuel ratio controller checking device |
| JPH0684688B2 (en) * | 1985-01-17 | 1994-10-26 | 忠雄 花岡 | Reconstruction construction method for cracks and peeling points of reinforced concrete structures |
| JPS6245866A (en) * | 1985-08-22 | 1987-02-27 | コニシ株式会社 | Method for reinforcing construction |
| JPS6424964A (en) * | 1987-07-21 | 1989-01-26 | P S Concrete | Method of repair construction of concrete structure |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52104991A (en) * | 1976-02-28 | 1977-09-02 | Bosch Gmbh Robert | Method and apparatus for sighting operation preparing state for oxygen measuring and detecting device |
-
1979
- 1979-08-29 JP JP10919879A patent/JPS5633539A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52104991A (en) * | 1976-02-28 | 1977-09-02 | Bosch Gmbh Robert | Method and apparatus for sighting operation preparing state for oxygen measuring and detecting device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5633539A (en) | 1981-04-04 |
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