JPH0727003A - Air-fuel ratio controller of engine - Google Patents
Air-fuel ratio controller of engineInfo
- Publication number
- JPH0727003A JPH0727003A JP19314493A JP19314493A JPH0727003A JP H0727003 A JPH0727003 A JP H0727003A JP 19314493 A JP19314493 A JP 19314493A JP 19314493 A JP19314493 A JP 19314493A JP H0727003 A JPH0727003 A JP H0727003A
- Authority
- JP
- Japan
- Prior art keywords
- fuel ratio
- air
- engine
- lean
- region
- 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.)
- Granted
Links
Landscapes
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、エンジンの空燃比を理
論空燃比よりもリーン側に設定したリーンバーンエンジ
ンの空燃比制御装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air-fuel ratio control device for a lean burn engine in which the air-fuel ratio of the engine is set leaner than the stoichiometric air-fuel ratio.
【０００２】[0002]
【従来の技術】エンジンの燃費を低減する手段として、
低負荷側で比較的出力要求が大きくない運転領域におい
ては理論空燃比よりもリーン側、それも、２０とか２２
といった超リーンの空燃比で運転することが従来から行
われている。2. Description of the Related Art As means for reducing fuel consumption of an engine,
In the operating region where the output demand is relatively small on the low load side, it is leaner than the stoichiometric air-fuel ratio, that is, 20 or 22.
It has been practiced to operate with a super lean air-fuel ratio.
【０００３】ところで、このようなリーンバーン運転を
行うエンジンでは、リーン領域から加速する時にトルク
不足で加速性が確保できないという問題があった。そこ
で、例えば特開昭６０−１３９３６号公報に記載された
制御装置では、定常時にはリーンバーン運転を行い、加
速時には空燃比を理論空燃比に制御することによって加
速時のトルクを確保するようにしている。By the way, in such an engine that performs lean burn operation, there is a problem that acceleration cannot be ensured due to insufficient torque when accelerating from a lean region. Therefore, for example, in the control device disclosed in Japanese Patent Laid-Open No. 60-13936, lean burn operation is performed during steady state, and the air-fuel ratio is controlled to the stoichiometric air-fuel ratio during acceleration to secure torque during acceleration. There is.
【０００４】[0004]
【発明が解決しようとする課題】上記のように定常時は
２０とか２２といった超リーン設定の空燃比で運転する
ことによってＮＯｘ排出量の増大を抑えつつ燃費を低減
し、加速時にはトルクアップのため空燃比をリッチ側に
切り換える場合に、加速時に空燃比を中途半端に小さく
して例えば１６とか１８にしたのでは、このあたりの空
燃比はＮＯｘ（窒素酸化物）の排出量が増大する領域に
あるため、ＮＯｘが増大しエミッションの悪化を招いて
しまう。そこで、このように定常時にはリーン空燃比で
あったものを加速時にリッチ設定に切り換えるに場合
に、加速時の空燃比は上記のように理論空燃比に設定す
るのが普通である。しかし、この場合は、加速過渡時に
空燃比が２０とか２２とかいった超リーン設定の空燃比
領域から、例えばλ（空気過剰率）＝１の空燃比領域へ
いきなり移行することによって、トルクショックが発生
する。このトルクショックは、運転者がアクセルを強く
踏んで急加速するような時は許容されるが、アクセル開
度の変化が緩やかで、急速なトルクアップが必要でない
緩加速の状態では、ショックが大きく、リニアな加速性
が得られなくなる。また、必要以上に空燃比リッチの領
域が広がることになって、燃費が悪くなるという弊害も
生ずる。As described above, in the steady state, by operating with an air-fuel ratio of a super lean setting such as 20 or 22, fuel consumption is reduced while suppressing an increase in NOx emissions, and torque is increased during acceleration. When the air-fuel ratio is switched to the rich side, the air-fuel ratio is reduced to halfway during acceleration, for example, 16 or 18, so that the air-fuel ratio around this is in the region where the emission amount of NOx (nitrogen oxide) increases. Therefore, NOx is increased and the emission is deteriorated. Therefore, when switching from the lean air-fuel ratio at the steady state to the rich setting at the acceleration, the air-fuel ratio at the acceleration is usually set to the stoichiometric air-fuel ratio as described above. However, in this case, by the air-fuel ratio during acceleration transition from air-fuel ratio range of 20 Toka 22 Toka said ultra lean setting, is suddenly shifts example λ to (air excess ratio) = 1 in the air-fuel ratio range, the torque shock Occurs. This torque shock is tolerable when the driver strongly presses the accelerator to accelerate suddenly, but the shock is large in the state of gentle acceleration where the accelerator opening changes slowly and rapid torque increase is not required. , The linear acceleration cannot be obtained. In addition, the air-fuel ratio rich region is expanded more than necessary, which causes a problem that fuel efficiency is deteriorated.
【０００５】本発明は上記問題点に鑑みてなされたもの
であって、定常時には燃費低減のため空燃比をリーン側
に設定するエンジンにおいて、加速過渡時に、必要なエ
ンジントルクを確保するとともに、ＮＯｘ排出量の増大
を抑えつつリニアな加速性が得られるようにすることを
目的とする。The present invention has been made in view of the above problems, and in an engine in which the air-fuel ratio is set to a lean side in order to reduce fuel consumption in a steady state, a necessary engine torque is secured during an acceleration transition and NOx The purpose is to obtain linear acceleration while suppressing the increase in emission amount.
【０００６】[0006]
【課題を解決するための手段】本発明は、エンジンの加
速時に空燃比をリーン設定から例えば理論空燃比へ移行
する場合に、空燃比の急激な変化による失火等によって
ＮＯｘ排出量が一時的に増加するという現象があること
から、理論空燃比そのものによるＮＯｘ排出量はリーン
設定と理論空燃比との間の中間空燃比を使用した場合に
比べて少なくても、リッチ移行後の所定期間についてい
えば、中間空燃比に制御した場合の方が、いきなり理論
空燃比へ移行した場合よりもＮＯｘの排出量がトータル
としては少ない場合があることに着目し、緩加速時等に
おいては、いきなり理論空燃比へ移行するよりも、時間
を限って中間空燃比を使用する方が、燃費，エミッショ
ンおよび加速性のいずれにおいても有利であるという知
見を得たことによるものであって、その構成は図１の
（ａ）に示すとおりである。すなわち、本発明に係るエ
ミッションの空燃比制御装置は、エンジンの運転状態を
検出する運転状態検出手段と、該運転状態検出手段の出
力を受け、低負荷側に設定した第１リーン空燃比領域に
おいてエンジンの空燃比を理論空燃比よりもリーン側の
第１リーン空燃比に制御する第１空燃比制御手段と、前
記運転状態検出手段の出力を受け、前記第１リーン空燃
比領域より高負荷側に設定した理論空燃比領域において
エンジンの空燃比を理論空燃比に制御する第２空燃比制
御手段と、前記運転状態検出手段の出力を受け、所定の
加速状態を判定する加速判定手段と、該加速判定手段の
出力を受け、所定の第２リーン空燃比領域においてエン
ジンが所定の加速状態に入ったときに、加速開始から所
定期間はエンジンの空燃比を前記第１リーン空燃比より
もリッチ側で理論空燃比よりもリーン側の第２リーン空
燃比とするよう前記第１空燃比制御手段および第２空燃
比制御手段による空燃比制御に変更を加える空燃比変更
手段を備えたことを特徴とする。According to the present invention, when the air-fuel ratio is changed from a lean setting to a stoichiometric air-fuel ratio when the engine is accelerated, the NOx emission amount is temporarily changed due to a misfire due to a rapid change of the air-fuel ratio. Since there is a phenomenon of increasing, the NOx emission amount due to the stoichiometric air-fuel ratio itself is smaller than that when using an intermediate air-fuel ratio between the lean setting and the stoichiometric air-fuel ratio, even if it is for the predetermined period after the rich transition. For example, paying attention to the fact that the total amount of NOx emission may be smaller when the air-fuel ratio is controlled to an intermediate value than when the air-fuel ratio is suddenly changed to the theoretical air-fuel ratio. Based on the finding that it is more advantageous to use the intermediate air-fuel ratio for a limited time than to change to the fuel ratio in terms of fuel economy, emission, and acceleration. Be one, the configuration is shown in (a) of FIG. That is, the air-fuel ratio control apparatus for emissions according to the present invention, in the first lean air-fuel ratio region set to the low load side, receiving the output of the operating state detecting means for detecting the operating state of the engine and the operating state detecting means. First air-fuel ratio control means for controlling the air-fuel ratio of the engine to a first lean air-fuel ratio that is leaner than the stoichiometric air-fuel ratio, and an output of the operating state detection means, and a higher load side than the first lean air-fuel ratio region. Second stoichiometric air-fuel ratio control means for controlling the air-fuel ratio of the engine to the stoichiometric air-fuel ratio in the stoichiometric air-fuel ratio region set to, acceleration determining means for receiving a predetermined acceleration state by receiving the output of the operating state detecting means, When the engine enters the predetermined acceleration state in the second predetermined lean air-fuel ratio region in response to the output of the acceleration determination means, the air-fuel ratio of the engine is set to the first lean air-fuel ratio for a predetermined period from the start of acceleration. An air-fuel ratio changing means for changing the air-fuel ratio control by the first air-fuel ratio control means and the second air-fuel ratio control means so that the second lean air-fuel ratio is leaner than the stoichiometric air-fuel ratio and leaner than the stoichiometric air-fuel ratio. It is characterized by that.
【０００７】ここで、前記所定期間は、空燃比を前記第
２リーン空燃比としたことによるＮＯｘ排出量の増加分
が、空燃比を前記第１リーン空燃比から理論空燃比へ移
行させた場合のＮＯｘ排出量の増加分よりも少なくなる
期間とするのがよい。Here, during the predetermined period, when the increase in the NOx emission amount due to the air-fuel ratio being the second lean air-fuel ratio causes the air-fuel ratio to shift from the first lean air-fuel ratio to the stoichiometric air-fuel ratio. It is preferable that the period is less than the increase in the NOx emission amount.
【０００８】また、前記第２リーン空燃比領域は、吸入
空気量が飽和する運転領域で、かつ、前記第１リーン空
燃比領域と前記理論空燃比領域との間に設定することが
できる。Further, the second lean air-fuel ratio region can be set in an operating region where the intake air amount is saturated and between the first lean air-fuel ratio region and the stoichiometric air-fuel ratio region.
【０００９】また、前記所定期間は、前記第２リーン空
燃比が理論空燃比に近い程短いものとするのがよい。It is preferable that the predetermined period is shorter as the second lean air-fuel ratio is closer to the stoichiometric air-fuel ratio.
【００１０】また、本発明を適用するエンジンは、前記
第１リーン空燃比領域において気筒内にスワールを生成
する手段を有するものが有利である。Further, it is advantageous that the engine to which the present invention is applied has means for generating swirl in the cylinder in the first lean air-fuel ratio region.
【００１１】また、リーン空燃比からリッチ空燃比への
移行領域を吸入空気量が飽和するゼロミリブースト近傍
に設定するような場合は、移行領域近傍では吸入空気量
の制御によるトルクアップが効かないので、加速時のト
ルクアップは空燃比のリッチ側への制御によって行うこ
とになるが、特にそのような場合のリニアな加速性を確
保するため、本発明に係るエンジンの空燃比制御装置
は、図１の（ｂ）に示すように、エンジンの運転状態を
検出する運転状態検出手段と、該運転状態検出手段の出
力を受け、定常運転時において、低負荷側にエンジンの
空燃比を理論空燃比よりもリーン側に制御するリーン空
燃比領域を設定し、該リーン空燃比領域より高負荷側に
エンジンの空燃比を理論空燃比に制御する理論空燃比領
域を設定した第１の空燃比マップに基づいてエンジンの
空燃比を制御する定常時空燃比制御手段と、前記運転状
態検出手段の出力を受け、過渡運転時において、低負荷
側にエンジンの空燃比を理論空燃比よりもリーン側の第
１リーン空燃比に制御する第１リーン空燃比領域を設定
し、高負荷側にエンジンの空燃比を理論空燃比に制御す
る理論空燃比領域と設定するとともに、これら第１リー
ン空燃比領域と理論空燃比領域との間に前記第１リーン
空燃比よりもリッチ側で理論空燃比よりもリーン側の第
２リーン空燃比に制御する第２空燃比領域を設定した第
２の空燃比マップに基づいてエンジンの空燃比を制御す
る過渡時空燃比制御手段を備えたものとすることができ
る。Further, in the case where the transition region from the lean air-fuel ratio to the rich air-fuel ratio is set near zero milliboost where the intake air amount is saturated, torque increase due to control of the intake air amount is not effective near the transition region. Therefore, torque up during acceleration will be performed by control to the rich side of the air-fuel ratio, but in particular in order to ensure linear acceleration in such a case, the engine air-fuel ratio control device according to the present invention, As shown in FIG. 1 (b), an operating state detecting means for detecting an operating state of the engine and an output of the operating state detecting means are received, and in steady operation, the air-fuel ratio of the engine is set to a theoretical value on the low load side. A first air-fuel ratio region for controlling the lean air-fuel ratio region of the fuel ratio is set, and a stoichiometric air-fuel ratio region for controlling the air-fuel ratio of the engine to the stoichiometric air-fuel ratio is set on the higher load side of the lean air-fuel ratio region. Steady-time air-fuel ratio control means for controlling the air-fuel ratio of the engine based on the fuel ratio map, and the output of the operating state detection means, and during transient operation, the air-fuel ratio of the engine is leaner than the theoretical air-fuel ratio on the low load side. The first lean air-fuel ratio region for controlling the first lean air-fuel ratio is set, and the stoichiometric air-fuel ratio region for controlling the engine air-fuel ratio to the stoichiometric air-fuel ratio is set on the high load side. And a stoichiometric air-fuel ratio region, a second air-fuel ratio map in which a second air-fuel ratio region for controlling to a second lean air-fuel ratio which is richer than the first lean air-fuel ratio and leaner than the stoichiometric air-fuel ratio is set. It is possible to provide a transient air-fuel ratio control means for controlling the air-fuel ratio of the engine based on the above.
【００１２】[0012]
【作用】低負荷側に第１リーン空燃比領域を設定し、該
第１リーン空燃比領域より高負荷側に理論空燃比領域を
設定するとともに、所定の第２リーン空燃比領域におい
てエンジンが緩加速時等所定の加速状態に入ったとき
に、加速開始から所定期間はエンジンの空燃比を第１リ
ーン空燃比よりもリッチ側で理論空燃比よりもリーン側
の第２リーン空燃比とするよう構成されたエンジンの空
燃比制御装置では、例えば、前記所定期間を、空燃比を
第２リーン空燃比としたことによるＮＯｘ排出量の増加
分が、空燃比を第１リーン空燃比から理論空燃比へ移行
させた場合のＮＯｘ排出量の増加分よりも少なくなる期
間とすることにより、また、第２リーン空燃比領域を、
吸入空気量が飽和する運転領域で、かつ、第１リーン空
燃比領域と理論空燃比領域との間に設定することによ
り、あるいは、また、前記所定期間を、第２リーン空燃
比が理論空燃比に近い程短いものとすることによって、
空燃比をリーン設定から理論空燃比へいきなり切り換え
る場合に比較して、燃費を低減し、また、ＮＯｘの増加
量をトータルとして少なくするとともに、トルクショッ
クを抑えてリニアな加速性を実現することができる。ま
た、第１リーン空燃比領域において気筒内にスワールを
生成する手段を設けることにより、該領域においてスワ
ールにより点火プラグまわりにリッチな混合気を集めて
着火性を向上させることができ、それにより、超リーン
空燃比での運転が可能となる。The first lean air-fuel ratio region is set on the low load side, the stoichiometric air-fuel ratio region is set on the higher load side than the first lean air-fuel ratio region, and the engine is slowed down in the predetermined second lean air-fuel ratio region. When entering a predetermined acceleration state such as during acceleration, the air-fuel ratio of the engine is set to the second lean air-fuel ratio which is richer than the first lean air-fuel ratio and leaner than the stoichiometric air-fuel ratio for a predetermined period from the start of acceleration. In the engine air-fuel ratio control device configured, for example, the increase in the NOx emission amount due to the air-fuel ratio being set to the second lean air-fuel ratio for the predetermined period causes the air-fuel ratio to change from the first lean air-fuel ratio to the theoretical air-fuel ratio. The second lean air-fuel ratio region is set by setting the period in which the amount of NOx emission becomes smaller than the amount of increase in the case of shifting to the second lean air-fuel ratio region.
By setting it in the operating region where the intake air amount is saturated and between the first lean air-fuel ratio region and the stoichiometric air-fuel ratio region, or for the predetermined period, the second lean air-fuel ratio becomes the stoichiometric air-fuel ratio. By making it shorter as
Compared to the case where the air-fuel ratio is suddenly switched from the lean setting to the theoretical air-fuel ratio, it is possible to reduce fuel consumption, reduce the amount of NOx increase in total, and suppress torque shock to realize linear acceleration. it can. Further, by providing a means for generating swirl in the cylinder in the first lean air-fuel ratio region, it is possible to improve the ignitability by collecting a rich air-fuel mixture around the spark plug by the swirl in the region. It becomes possible to operate at a super lean air-fuel ratio.
【００１３】また、リーン空燃比領域と該リーン空燃比
領域より高負荷側の理論空燃比領域とを設定した第１の
空燃比マップと、第１リーン空燃比領域と理論空燃比領
域と第１リーン空燃比よりもリッチ側で理論空燃比より
もリーン側の第２空燃比領域とを設定した第２の空燃比
マップとを設け、定常時には第１の空燃比マップに基づ
いて空燃比を制御し、過渡時には第２の空燃比マップに
基づいて空燃比を制御するよう構成されたエンジンの制
御装置では、特に、リーン空燃比からリッチ空燃比への
移行領域がゼロミリブースト近傍に設定された場合等に
おいて、吸入空気量の制御によるトルクアップが効かな
い分を空燃比のリッチ側への制御によって補いつつリニ
アな加速性を確保することができる。A first air-fuel ratio map in which a lean air-fuel ratio region and a stoichiometric air-fuel ratio region on the higher load side than the lean air-fuel ratio region are set, a first lean air-fuel ratio region, a stoichiometric air-fuel ratio region, and a first air-fuel ratio region A second air-fuel ratio map that sets a second air-fuel ratio region that is richer than the lean air-fuel ratio and leaner than the stoichiometric air-fuel ratio is provided, and the air-fuel ratio is controlled based on the first air-fuel ratio map in a steady state. However, in the engine control device configured to control the air-fuel ratio on the basis of the second air-fuel ratio map during the transition, in particular, the transition region from the lean air-fuel ratio to the rich air-fuel ratio is set near zero milli boost. In such a case, linear acceleration can be ensured while supplementing the amount of torque that is not increased by controlling the intake air amount by controlling the air-fuel ratio to the rich side.
【００１４】[0014]
実施例１．図２は本発明の実施例１のシステム図であ
る。図において、１はエンジン本体であり、２はエンジ
ンの吸気通路、３は排気通路をそれぞれ示す。Example 1. FIG. 2 is a system diagram of the first embodiment of the present invention. In the figure, 1 is an engine body, 2 is an intake passage of the engine, and 3 is an exhaust passage.
【００１５】エンジン本体１には、各気筒の燃焼室４に
対しそれぞれ二つの吸気ポート５ａ，５ｂと二つの排気
ポート６ａ，６ｂが設けられ、また、点火プラグ７が設
置されている。そして、吸気通路２は、サージタンク部
の下流が各気筒の二つの吸気ポート５ａ，５ｂに対しそ
れぞれ独立して連通するよう気筒毎に二つの独立吸気通
路部２ａ，２ｂに区画されている。The engine body 1 is provided with two intake ports 5a and 5b and two exhaust ports 6a and 6b for the combustion chamber 4 of each cylinder, and an ignition plug 7 is also provided. The intake passage 2 is divided into two independent intake passage portions 2a and 2b for each cylinder so that the downstream side of the surge tank portion communicates with the two intake ports 5a and 5b of each cylinder independently.
【００１６】気筒毎の上記二つの吸気ポート５ａ，５ｂ
は、一方（５ａ）がストレートポート、他方がヘリカル
ポート（５ｂ）であって、ヘリカルポートとされた方の
吸気ポート（プライマリポート）５ｂに連通する独立通
路部２ｂには燃料噴射弁８が設置され、ストレートポー
トとされた方の吸気ポート（セカンダリポート）５ａに
連通する独立通路部２ａには該通路部２ａを開閉するこ
とによって筒内スワールを制御するスワールコントロー
ルバルブ（ＳＣＶ）９が設けられている。そして、吸気
通路２は先端がエアクリーナ１０に接続され、エアクリ
ーナ１０との接続部にはエアフローメータ１１が、ま
た、エアフローメータ１１からサージタンク部まで延び
る上流側通路部にスロットル弁１２が配置されている。
また、排気通路３には触媒コンバータ１３が接続され、
また、触媒コンバータ１３の上流にＯ2センサ１４が設
置されている。The above-mentioned two intake ports 5a and 5b for each cylinder
One side (5a) is a straight port, the other side is a helical port (5b), and the fuel injection valve 8 is installed in the independent passage portion 2b communicating with the intake port (primary port) 5b which is the helical port. A swirl control valve (SCV) 9 for controlling the in-cylinder swirl is provided in the independent passage portion 2a communicating with the intake port (secondary port) 5a which is the straight port. ing. The intake passage 2 is connected at its tip to the air cleaner 10, an air flow meter 11 is provided at a connection portion with the air cleaner 10, and a throttle valve 12 is provided at an upstream passage portion extending from the air flow meter 11 to the surge tank portion. There is.
A catalytic converter 13 is connected to the exhaust passage 3,
An O 2 sensor 14 is installed upstream of the catalytic converter 13.
【００１７】エンジンにはマイクロコンピュータによっ
て構成されたコントロールユニット１５が設けられてい
る。このコントロールユニット１５には、エンジン本体
１に設けられたクランク角センサ１６からクランク角信
号が入力され、エアフローメータ１１から吸入空気量信
号が入力され、Ｏ2センサ１４から空燃比信号が入力さ
れる。また、その他、アクセル踏み込み量すなわちアク
セル開度等がコントロールユニット１５に入力される。
そして、コントロールユニット１５によって燃料噴射弁
８が制御され、また、ＳＣＶ９が制御され、それにより
空燃比およびスワールの制御が行われる。The engine is provided with a control unit 15 composed of a microcomputer. To the control unit 15, a crank angle signal is input from a crank angle sensor 16 provided in the engine body 1, an intake air amount signal is input from the air flow meter 11, and an air-fuel ratio signal is input from the O 2 sensor 14. . In addition, the accelerator depression amount, that is, the accelerator opening degree is input to the control unit 15.
Then, the control unit 15 controls the fuel injection valve 8 and also controls the SCV 9, thereby controlling the air-fuel ratio and the swirl.
【００１８】空燃比の制御では、アクセル開度とエンジ
ン回転数をパラメータとして、低回転低負荷側に例えば
空燃比２２のリーン領域（リーン空燃比領域）を設定
し、それより高負荷側にストイキ領域（理論空燃比領
域）を設定し、さらにその高負荷側を例えば空燃比１３
のエンリッチ領域を設定する空燃比アップが使用され
る。そして、それぞれの領域でエンジン回転数と充填量
に基づいて目標空燃比が設定され、クランク角信号から
算出されるエンジン回転数と吸入空気量に基づいて燃料
噴射の基本噴射量が演算されて、それに水温等による各
種補正が加えられ、さらにＯ2センサ１４によって検出
した空燃比と目標空燃比との偏差に基づく空燃比フィー
ドバック補正が加えられて、燃料噴射量が決定され、そ
の燃料噴射量に応じた噴射パルスがインジェクタ８に出
力されることによってエンジンの空燃比が目標空燃比に
制御される。In the control of the air-fuel ratio, a lean region of the air-fuel ratio 22 (lean air-fuel ratio region) is set on the low rotation and low load side using the accelerator opening and the engine speed as parameters, and the stoichiometric control is set on the higher load side. A region (theoretical air-fuel ratio region) is set, and the high load side is set to, for example, the air-fuel ratio 13
The air-fuel ratio increase that sets the enrichment region of is used. Then, the target air-fuel ratio is set in each region based on the engine speed and the filling amount, and the basic injection amount of the fuel injection is calculated based on the engine speed and the intake air amount calculated from the crank angle signal, Various corrections based on the water temperature and the like are added thereto, and further air-fuel ratio feedback correction based on the deviation between the air-fuel ratio detected by the O 2 sensor 14 and the target air-fuel ratio is added to determine the fuel injection amount, and the fuel injection amount is determined. By outputting a corresponding injection pulse to the injector 8, the air-fuel ratio of the engine is controlled to the target air-fuel ratio.
【００１９】また、ＳＣＶ９はダイアフラム式のアクチ
ュエータ１７に連結されている。このアクチュエータ１
７は２段配置のアクチュエータ室を有するものであっ
て、スロットル弁１２下流の吸気負圧を各段のアクチュ
エータ室に導入する負圧通路１８が設けられ、該負圧通
路１８には、片側のアクチュエータ室のみを選択的に大
気開放に切り換え可能とする三方ソレノイドバルブ１９
が配置されている。そして、ＳＣＶ９はアクチュエータ
室に所定値以上の吸気負圧が導入されることによって開
かれ、また、上記三方ソレノイドバルブ１９が切り換え
られることによって２段階に開度が調整される。The SCV 9 is connected to a diaphragm type actuator 17. This actuator 1
7 has a two-stage actuator chamber, and a negative pressure passage 18 for introducing intake negative pressure downstream of the throttle valve 12 into the actuator chamber of each stage is provided, and the negative pressure passage 18 has one side. Three-way solenoid valve 19 that can selectively switch only the actuator chamber to open to the atmosphere
Are arranged. Then, the SCV 9 is opened by introducing an intake negative pressure of a predetermined value or more into the actuator chamber, and the opening is adjusted in two steps by switching the three-way solenoid valve 19.
【００２０】リーン領域では、スロットル弁１２下流の
吸気負圧は設定値以上であって、これがアクチュエータ
室に導入されることによりＳＣＶ９は閉方向に駆動され
る。そして、このリーン領域の内、エンジン回転数が設
定回転数より高回転側では、三方ソレノイドバルブ１９
によってアクチュエータ室の片側が大気に開放され、そ
の結果、ＳＣＶは半開となり、筒内に弱スワールが形成
される。そして、リーン領域の内、エンジン回転数が設
定回転数以下の領域では、三方ソレノイドバルブ１９が
負圧導入側に制御され、両アクチュエータ室に吸気負圧
が導入される。このとき、ＳＣＶ９は全閉となり、筒内
に強スワールが形成される。また、理論空燃比領域では
吸気負圧が設定値より小さくなり、その結果、アクチュ
エータ１７は作動せず、ＳＣＶ９が全開となる。In the lean region, the intake negative pressure downstream of the throttle valve 12 is equal to or higher than the set value, and the SCV 9 is driven in the closing direction by introducing this into the actuator chamber. In the lean region, when the engine speed is higher than the set speed, the three-way solenoid valve 19
This opens one side of the actuator chamber to the atmosphere, resulting in a half-open SCV and a weak swirl in the cylinder. Then, in the lean region where the engine speed is equal to or lower than the set engine speed, the three-way solenoid valve 19 is controlled to the negative pressure introduction side, and the intake negative pressure is introduced into both actuator chambers. At this time, the SCV 9 is fully closed, and a strong swirl is formed in the cylinder. Further, in the stoichiometric air-fuel ratio region, the intake negative pressure becomes smaller than the set value, and as a result, the actuator 17 does not operate and the SCV 9 is fully opened.
【００２１】また、この実施例においては、加速時にＮ
Ｏｘの排出量を抑えつつリニアな加速性が得られるよう
にするため、加速状態の判定を行いスロットル開度（ア
クセル開度）の変化が比較的小さい緩加速時には、リー
ン空燃比から理論空燃比への移行領域で達した後、所定
期間（中間空燃比実行期間）Ｔの間は空燃比を例えば１
６の中間空燃比に制御し、所定期間Ｔが経過した時点で
理論空燃比に移行させるようにしている。図３の斜線領
域は、このような中間空燃比を使用する期間に相当する
領域を模式的に示すものである。Further, in this embodiment, N
In order to obtain linear acceleration while suppressing the amount of Ox emissions, the acceleration state is determined and the lean air-fuel ratio changes from the theoretical air-fuel ratio to the theoretical air-fuel ratio during slow acceleration when the change in throttle opening (accelerator opening) is relatively small. After reaching in the transition region, the air-fuel ratio is set to, for example, 1 during a predetermined period (intermediate air-fuel ratio execution period) T.
The intermediate air-fuel ratio is controlled to 6 and the stoichiometric air-fuel ratio is shifted to when the predetermined period T has elapsed. The shaded area in FIG. 3 schematically shows the area corresponding to the period in which such an intermediate air-fuel ratio is used.
【００２２】上記加速状態の判定では、図４に示すよう
にリーン領域からストイキ領域への移行領域において、
移行ラインより所定時間Δｔ前のスロットル開度ｔｖｏ
２と移行ラインでのスロットル開度ｔｖｏ１とを求め、
次式によってスロットル開度の変化ｄを求める。In the acceleration state determination, as shown in FIG. 4, in the transition region from the lean region to the stoichiometric region,
Throttle opening tvo before a predetermined time Δt from the transition line
2 and the throttle opening tvo1 at the transition line,
The change d in the throttle opening is calculated by the following formula.
【００２３】ｄ＝（ｔｖｏ１−ｔｖｏ２）／Δｔ そして、ｄがしきい値ｄ１よりも小さいときに、上記の
ように所定期間Ｔの間だけ中間空燃比を使用する。D = (tvo1-tvo2) / Δt When d is smaller than the threshold value d1, the intermediate air-fuel ratio is used only for the predetermined period T as described above.
【００２４】上記所定期間Ｔは、中間空燃比によるＮＯ
ｘ増加分とリーンからストイキへといきなり空燃比を移
行させた場合の失火等によるＮＯｘ増加分を考慮して設
定される。During the predetermined period T, NO due to the intermediate air-fuel ratio
It is set in consideration of the increase in x and the increase in NOx due to misfire or the like when the air-fuel ratio is suddenly changed from lean to stoichiometric.
【００２５】図５は、リーン領域からストイキ領域へ移
行する時のスロットル開度変化と、中間空燃比を使う場
合、および使わない場合の、それぞれのＮＯｘの排出量
の変化を示している。なお、図はリーンからストイキへ
の移行時と加速開始が重なった場合を示す。それぞれの
場合のリーンから中間空燃比へ、あるいはリーンからス
トイキへ移行することによるＮＯｘ増加分は図の斜線部
分に相当する。そして、二つの場合のＮＯｘ増加分を比
較し、ＮＯｘ増加分ＭＮＯｘ×Ｔが、ストイキ移行の場
合のＮＯｘ増加分（失火等による増加分ＮＯｘ３とスト
イキによる増加分ＳＮＯｘ×Ｔとの和）より少なくなる
よう、つぎの関係式を立てる。FIG. 5 shows changes in the throttle opening when shifting from the lean region to the stoichiometric region, and changes in the NOx emission amount when the intermediate air-fuel ratio is used and when it is not used. The figure shows the case where the start of acceleration coincides with the transition from lean to stoichiometric. In each case, the increase in NOx due to the shift from lean to the intermediate air-fuel ratio or from lean to stoichiometric corresponds to the shaded area in the figure. Then, the NOx increase amount in the two cases is compared, and the NOx increase amount MNOx × T is smaller than the NOx increase amount (the sum of the increase amount NOx3 due to misfire and the increase amount SNOx × T due to stoichiometry) in the case of the stoichiometric transition. The following relational expression is established so that
【００２６】ＭＮＯｘ×Ｔ＜ＮＯｘ３＋ＳＮＯｘ×Ｔ Ｔ＜ＮＯｘ３／（ＭＮＯｘ−ＳＮＯｘ） そして、係数Ｋ（１以下の定数）を用いて次式により中
間空燃比実行期間Ｔを設定する。MNOx * T <NOx3 + SNOx * TT <NOx3 / (MNOx-SNOx) Then, the coefficient K (constant of 1 or less) is used to set the intermediate air-fuel ratio execution period T by the following equation.
【００２７】Ｔ＝Ｋ×ＮＯｘ３／（ＭＮＯｘ−ＳＮＯ
ｘ） 図６は、空燃比の設定に対するエンジントルクおよびＮ
Ｏｘ排出量の変化を示す。上記ＭＮＯｘおよびＳＮＯｘ
は図示のとおりである。中間空燃比の設定が変化すると
ＭＮＯｘは変化する。その結果、リーン側の所定空燃比
範囲では、上記期間Ｔは中間空燃比がリーンであるほど
長くなり、リッチであるほど短くなる。図７はこのよう
な中間空燃比と中間空燃比実行期間Ｔとの関係を示して
いる。また、図８および図９は、上記期間Ｔを一定とし
て、条件の異なる二つの場合のそれぞれの空燃比の変化
を示している。T = K × NOx3 / (MNOx-SNO
x) FIG. 6 shows the engine torque and N for the setting of the air-fuel ratio.
The change in Ox emissions is shown. The above MNOx and SNOx
Is as shown. MNOx changes when the setting of the intermediate air-fuel ratio changes. As a result, in the lean side predetermined air-fuel ratio range, the period T becomes longer as the intermediate air-fuel ratio becomes leaner and becomes shorter as the intermediate air-fuel ratio becomes richer. FIG. 7 shows such a relationship between the intermediate air-fuel ratio and the intermediate air-fuel ratio execution period T. Further, FIGS. 8 and 9 show changes in the air-fuel ratio in two cases under different conditions, with the period T being constant.
【００２８】また、図４によって説明した加速状態の判
定は、つぎのように他の方法で行うこともできる。すな
わち、他の方法としては、図１０に示すように、リーン
領域からストイキ領域への移行領域において、移行ライ
ンより所定時間Δｔ前のスロットル開度ｔｖｏ２と、２
Δｔ前のスロットル開度ｔｖｏ３と、移行ラインでのス
ロットル開度ｔｖｏ１とを求め、次式によってスロット
ル開度の変化ｓを求める。The determination of the acceleration state described with reference to FIG. 4 can also be performed by another method as follows. That is, as another method, as shown in FIG. 10, in the transition region from the lean region to the stoichiometric region, the throttle opening tvo2 before the predetermined time Δt from the transition line and 2
The throttle opening tvo3 before Δt and the throttle opening tvo1 on the transition line are obtained, and the change s of the throttle opening is obtained by the following equation.
【００２９】ｓ＝｛（ｔｖｏ１−ｔｖｏ２）／Δｔ−
（ｔｖｏ２−ｔｖｏ３）／Δｔ｝／Δｔ そして、ｓがしきい値ｓ１よりも小さいときに中間空燃
比を実行する加速状態と判定する。S = {(tvo1-tvo2) / Δt-
(Tvo2-tvo3) / Δt} / Δt Then, when s is smaller than the threshold value s1, it is determined that the vehicle is in the acceleration state in which the intermediate air-fuel ratio is executed.
【００３０】図１１はこの実施例の上記空燃比制御を実
行するフローチャートである。このフローチャートはＳ
１０１〜Ｓ１１４のステップからなり、スタートする
と、Ｓ１０１でエンジン回転数，吸入空気量，空燃比，
アクセル開度等の各種信号を読み込む。そして、Ｓ１０
２で、エンジン回転数と吸入空気量に基づいて燃料噴射
の基本パルスを演算する。FIG. 11 is a flow chart for executing the air-fuel ratio control of this embodiment. This flowchart is S
Steps 101 to S114 are started. When the engine starts, at S101, the engine speed, intake air amount, air-fuel ratio,
Read various signals such as accelerator opening. And S10
In step 2, the basic pulse for fuel injection is calculated based on the engine speed and the intake air amount.
【００３１】つぎに、Ｓ１０３で、エンジン回転数とア
クセル開度から、図３の空燃比マップによってリーン領
域かどうかを判定する。そして、リーン領域であれば、
つぎに、Ｓ１０４でスロットル開度（アクセル開度）の
動きによって加速かどうかを判定し、加速でなければ、
Ｓ１０５で空燃比をリーン設定とする。Next, at S103, it is judged from the engine speed and the accelerator opening degree whether or not it is in the lean range according to the air-fuel ratio map of FIG. And in the lean region,
Next, in S104, it is determined whether or not the vehicle is accelerating based on the movement of the throttle opening (accelerator opening).
The air-fuel ratio is set to lean in S105.
【００３２】Ｓ１０４で加速というときは、さらにＳ１
０６で、先に図４あるいは図１０により説明した方法で
アクセル開度の変化（ｄ，ｓ）を求めて、中間空燃比を
使用する緩加速の状態かどうかを判定する。そして、緩
加速でないときはＳ１０７で空燃比を理論空燃比に設定
する。When accelerating at S104, further acceleration at S1
At 06, the change (d, s) in the accelerator opening is obtained by the method previously described with reference to FIG. 4 or FIG. 10, and it is determined whether or not the state is the state of gentle acceleration using the intermediate air-fuel ratio. When the acceleration is not slow, the air-fuel ratio is set to the stoichiometric air-fuel ratio in S107.
【００３３】また、Ｓ１０６で緩加速というときは、Ｓ
１０８で加速後所定期間Ｔ内かどうかを判定し、所定期
間Ｔ内であれば、Ｓ１０９で空燃比を中間空燃比に設定
する。また、所定期間Ｔが経過したときは、Ｓ１０７へ
進んで空燃比を理論空燃比とする。When it is said that the acceleration is slow in S106, S
At 108, it is determined whether or not it is within a predetermined period T after acceleration, and if it is within the predetermined period T, the air-fuel ratio is set to an intermediate air-fuel ratio at S109. Further, when the predetermined period T has elapsed, the routine proceeds to S107, where the air-fuel ratio is made the stoichiometric air-fuel ratio.
【００３４】また、Ｓ１０３の判定でリーン領域でない
ときは、Ｓ１１０へ進んでストイキ領域かどうかを判定
し、ストイキ領域であれば、Ｓ１０７で空燃比を理論空
燃比とする。If it is not in the lean region in the determination of S103, the process proceeds to S110 to determine whether it is in the stoichiometric region, and if it is the stoichiometric region, the air-fuel ratio is set to the stoichiometric air-fuel ratio in S107.
【００３５】そして、Ｓ１０５，Ｓ１０７あるいはＳ１
０９で空燃比の設定を行った後は、Ｓ１１１へ進んでフ
ィードバック補正量を演算し、Ｓ１１３へ進む。Then, S105, S107 or S1
After setting the air-fuel ratio in 09, the process proceeds to S111, the feedback correction amount is calculated, and the process proceeds to S113.
【００３６】一方、Ｓ１１０の判定でストイキ領域でな
いというときは、Ｓ１１２でエンリッチ補正量を設定
し、Ｓ１１３へ進む。そして、Ｓ１１３でフィードバッ
ク補正量あるいはエンリッチ補正量を加えて最終パルス
を演算し、Ｓ１１４で噴射パルスをインジェクタ８に出
力する。On the other hand, if it is determined in S110 that the area is not in the stoichiometric range, the enrichment correction amount is set in S112, and the process proceeds to S113. Then, the final pulse is calculated by adding the feedback correction amount or the enrichment correction amount in S113, and the injection pulse is output to the injector 8 in S114.
【００３７】実施例２．つぎに、図１２および図１３に
よって本発明の実施例２を説明する。Example 2. Next, a second embodiment of the present invention will be described with reference to FIGS.
【００３８】この実施例では、リーン空燃比からリッチ
空燃比への移行領域を吸入空気量が飽和するゼロミリブ
ースト近傍に設定する場合に好適なもので、過渡時に
は、図１２の（ａ）に示すようなリーン領域とストイキ
領域とエンリッチ領域に加えてリーン領域とストイキ領
域との間に中間空燃比領域を設定した過渡時用の空燃比
マップ（ａ）を使用し、定常時には、図１２の（ｂ）に
示すようなリーン領域とストイキ領域とエンリッチ領域
を設定した定常時用の空燃比マップを使用する。この実
施例によれば、加速時に吸入空気量の制御によるトルク
アップが効かない分を空燃比制御によって補いつつリニ
アな加速性を確保することができる。This embodiment is suitable for setting the transition region from the lean air-fuel ratio to the rich air-fuel ratio in the vicinity of zero milli-boost where the intake air amount is saturated. At the time of transition, as shown in FIG. In addition to the lean region, the stoichiometric region, and the enriched region as shown, the air-fuel ratio map (a) for the transient time in which the intermediate air-fuel ratio region is set between the lean region and the stoichiometric region is used. The steady-state air-fuel ratio map in which the lean region, the stoichiometric region, and the enriched region are set as shown in (b) is used. According to this embodiment, it is possible to ensure linear acceleration while supplementing by air-fuel ratio control the amount of torque that is not increased by controlling the intake air amount during acceleration.
【００３９】図１３はこの実施例の制御を実行するフロ
ーチャートである。このフローチャートはＳ２０１〜Ｓ
２０７のステップからなり、スタートすると、まず、Ｓ
２０１でエンジン回転数，吸入空気量，アクセル開度等
の各種信号を読み込む。そして、Ｓ２０２でエンジン回
転数と吸入空気量から燃料噴射の基本パルスを演算す
る。そして、Ｓ２０３に進み、アクセル開度によって定
常時かどうかを判定し、定常時であれば、Ｓ２０４で定
常時用の空燃比マップを使用した空燃比フィードバック
制御を行い、定常時でなく過渡時という場合は、Ｓ２０
５へ進んで過渡時用の空燃比マップを使用した空燃比フ
ィードバック制御を行う。FIG. 13 is a flow chart for executing the control of this embodiment. This flowchart is from S201 to S
It consists of 207 steps, and when you start, first, S
At 201, various signals such as engine speed, intake air amount and accelerator opening are read. Then, in S202, a basic pulse for fuel injection is calculated from the engine speed and the intake air amount. Then, the routine proceeds to S203, where it is determined whether the engine is in the steady state based on the accelerator opening degree. If it is the steady state, the air-fuel ratio feedback control using the air-fuel ratio map for the steady state is performed in S204, and it is determined that the transient state is not the steady state. If S20
5, the air-fuel ratio feedback control using the air-fuel ratio map for transition is performed.
【００４０】そして、Ｓ２０６で最終パルスを演算し、
Ｓ２０７で噴射パルスをインジェクタに噴射する。Then, in S206, the final pulse is calculated,
In S207, an injection pulse is injected to the injector.
【００４１】[0041]
【発明の効果】本発明は以上のように構成されてている
ので、定常時に空燃比をリーン側に設定することによっ
て燃費低減を図り、加速過渡時にはエンジントルクを確
保するとともに、ＮＯｘの排出量を抑えつつリニアな加
速性が得られるようにすることができる。EFFECTS OF THE INVENTION Since the present invention is configured as described above, the fuel consumption is reduced by setting the air-fuel ratio to the lean side during steady state, the engine torque is secured during the acceleration transition, and the NOx emission amount is also increased. It is possible to obtain linear acceleration while suppressing the above.
【図１】本発明の全体構成図。FIG. 1 is an overall configuration diagram of the present invention.
【図２】本発明の実施例１のシステム図。FIG. 2 is a system diagram of the first embodiment of the present invention.
【図３】本発明の実施例１において使用する空燃比マッ
プ。FIG. 3 is an air-fuel ratio map used in Example 1 of the present invention.
【図４】本発明の実施例１における加速状態の判定方法
を説明する説明図。FIG. 4 is an explanatory diagram illustrating an acceleration state determination method according to the first embodiment of the present invention.
【図５】本発明の実施例１における中間空燃比実行期間
の設定方法を説明する説明図。FIG. 5 is an explanatory diagram illustrating a method of setting an intermediate air-fuel ratio execution period according to the first embodiment of the present invention.
【図６】本発明の実施例１における空燃比とエンジント
ルクおよびＮＯｘ排出量との関係を示す特性図。FIG. 6 is a characteristic diagram showing the relationship between the air-fuel ratio, engine torque, and NOx emission amount according to the first embodiment of the present invention.
【図７】本発明の実施例１における中間空燃比と中間空
燃比実行期間との関係を示す説明図。FIG. 7 is an explanatory diagram showing a relationship between an intermediate air-fuel ratio and an intermediate air-fuel ratio execution period according to the first embodiment of the present invention.
【図８】本発明の実施例１における空燃比の変化を示す
タイムチャート（場合１）。FIG. 8 is a time chart (case 1) showing changes in the air-fuel ratio in Example 1 of the present invention.
【図９】本発明の実施例１における空燃比の変化を示す
タイムチャート（場合２）。FIG. 9 is a time chart (case 2) showing changes in the air-fuel ratio in Example 1 of the present invention.
【図１０】本発明の実施例１における加速状態の他の判
定方法を説明する説明図。FIG. 10 is an explanatory diagram illustrating another method of determining the acceleration state according to the first embodiment of the present invention.
【図１１】本発明の実施例１の制御を実行するフローチ
ャート。FIG. 11 is a flowchart for executing control according to the first embodiment of the present invention.
【図１２】本発明の実施例２に使用する過渡時用および
定常時用の空燃比マップ。FIG. 12 is an air-fuel ratio map for transient use and steady-state use used in the second embodiment of the present invention.
【図１３】本発明の実施例２の制御を実行するフローチ
ャート。FIG. 13 is a flowchart for executing control according to the second embodiment of the present invention.
１ エンジン ５ａ 吸気ポート（ストレートポート） ５ｂ 吸気ポート（ヘリカルポート） ８ インジェクタ ９ スワールコントロールバルブ １５ コントロールユニット 1 engine 5a intake port (straight port) 5b intake port (helical port) 8 injector 9 swirl control valve 15 control unit
───────────────────────────────────────────────────── フロントページの続き (72)発明者 田賀 淳一 広島県安芸郡府中町新地３番１号 マツダ 株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junichi Taga 3-1, Shinchi Fuchu-cho, Aki-gun, Hiroshima Mazda Motor Corporation
Claims (6)
検出手段と、該運転状態検出手段の出力を受け、低負荷
側に設定した第１リーン空燃比領域においてエンジンの
空燃比を理論空燃比よりもリーン側の第１リーン空燃比
に制御する第１空燃比制御手段と、前記運転状態検出手
段の出力を受け、前記第１リーン空燃比領域より高負荷
側に設定した理論空燃比領域においてエンジンの空燃比
を理論空燃比に制御する第２空燃比制御手段と、前記運
転状態検出手段の出力を受け、所定の加速状態を判定す
る加速判定手段と、該加速判定手段の出力を受け、所定
の第２リーン空燃比領域においてエンジンが所定の加速
状態に入ったときに、加速開始から所定期間はエンジン
の空燃比を前記第１リーン空燃比よりもリッチ側で理論
空燃比よりもリーン側の第２リーン空燃比とするよう前
記第１空燃比制御手段および第２空燃比制御手段による
空燃比制御に変更を加える空燃比変更手段を備えたこと
を特徴とするエンジンの空燃比制御装置。1. An operating state detecting means for detecting an operating state of the engine, and an output of the operating state detecting means, wherein an air-fuel ratio of the engine is set to a theoretical air-fuel ratio in a first lean air-fuel ratio region set to a low load side. Engine in a stoichiometric air-fuel ratio region set to a higher load side than the first lean air-fuel ratio region by receiving the output of the first air-fuel ratio control device for controlling the lean lean first air-fuel ratio and the operating condition detection device. Second air-fuel ratio control means for controlling the air-fuel ratio of the above to the stoichiometric air-fuel ratio, an acceleration determination means for receiving an output of the operating state detection means and determining a predetermined acceleration state, and an output of the acceleration determination means for receiving a predetermined When the engine enters a predetermined acceleration state in the second lean air-fuel ratio range, the air-fuel ratio of the engine is richer than the first lean air-fuel ratio and leaner than the theoretical air-fuel ratio for a predetermined period from the start of acceleration. Side air-fuel ratio control means for changing the air-fuel ratio control by the first air-fuel ratio control means and the second air-fuel ratio control means so as to obtain the second lean air-fuel ratio on the side. .
ン空燃比としたことによるＮＯｘ排出量の増加分が、空
燃比を前記第１リーン空燃比から理論空燃比へ移行させ
た場合のＮＯｘ排出量の増加分よりも少なくなる期間と
した請求項１記載のエンジンの空燃比制御装置。2. When the air-fuel ratio is changed from the first lean air-fuel ratio to the stoichiometric air-fuel ratio due to an increase in the NOx emission amount due to the air-fuel ratio being the second lean air-fuel ratio during the predetermined period. The air-fuel ratio control device for an engine according to claim 1, wherein the period is set to be less than the increase in the NOx emission amount.
量が飽和する運転領域で、かつ、前記第１リーン空燃比
領域と前記理論空燃比領域との間に設定した請求項１記
載のエンジンの空燃比制御装置。3. The second lean air-fuel ratio region is an operating region where the intake air amount is saturated, and is set between the first lean air-fuel ratio region and the stoichiometric air-fuel ratio region. Engine air-fuel ratio control device.
が理論空燃比に近い程短いものとする請求項１記載のエ
ンジンの空燃比制御装置。4. The engine air-fuel ratio control apparatus according to claim 1, wherein the predetermined period is shorter as the second lean air-fuel ratio is closer to the stoichiometric air-fuel ratio.
において気筒内にスワールを生成する手段を有するもの
である請求項１記載のエンジンの空燃比制御装置。5. The air-fuel ratio control system for an engine according to claim 1, wherein the engine has means for generating swirl in the cylinder in the first lean air-fuel ratio region.
検出手段と、該運転状態検出手段の出力を受け、定常運
転時において、低負荷側にエンジンの空燃比を理論空燃
比よりもリーン側に制御するリーン空燃比領域を設定
し、該リーン空燃比領域より高負荷側にエンジンの空燃
比を理論空燃比に制御する理論空燃比領域を設定した第
１の空燃比マップに基づいてエンジンの空燃比を制御す
る定常時空燃比制御手段と、前記運転状態検出手段の出
力を受け、過渡運転時において、低負荷側にエンジンの
空燃比を理論空燃比よりもリーン側の第１リーン空燃比
に制御する第１リーン空燃比領域を設定し、高負荷側に
エンジンの空燃比を理論空燃比に制御する理論空燃比領
域と設定するとともに、これら第１リーン空燃比領域と
理論空燃比領域との間に前記第１リーン空燃比よりもリ
ッチ側で理論空燃比よりもリーン側の第２リーン空燃比
に制御する第２空燃比領域を設定した第２の空燃比マッ
プに基づいてエンジンの空燃比を制御する過渡時空燃比
制御手段を備えたことを特徴とするエンジンの空燃比制
御装置。6. An operating condition detecting means for detecting an operating condition of the engine, and an output of the operating condition detecting means, and during normal operation, the air-fuel ratio of the engine is leaner than the theoretical air-fuel ratio on the low load side. The lean air-fuel ratio region to be controlled is set, and the air-fuel ratio of the engine is set based on the first air-fuel ratio map in which the stoichiometric air-fuel ratio region for controlling the air-fuel ratio of the engine to the stoichiometric air-fuel ratio is set to a higher load side than the lean air-fuel ratio region. The output of the steady-state air-fuel ratio control means for controlling the fuel ratio and the operating state detection means is received, and during transient operation, the air-fuel ratio of the engine is controlled to the low load side to the first lean air-fuel ratio leaner than the theoretical air-fuel ratio. The first lean air-fuel ratio region is set to a stoichiometric air-fuel ratio region for controlling the engine air-fuel ratio to the stoichiometric air-fuel ratio on the high load side, and between the first lean air-fuel ratio region and the stoichiometric air-fuel ratio region. The air-fuel ratio of the engine is set based on the second air-fuel ratio map in which the second air-fuel ratio region is set to control to the second lean air-fuel ratio which is richer than the first lean air-fuel ratio and leaner than the stoichiometric air-fuel ratio. An engine air-fuel ratio control device comprising a transient air-fuel ratio control means for controlling.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19314493A JP3338907B2 (en) | 1993-07-07 | 1993-07-07 | Engine air-fuel ratio control device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19314493A JP3338907B2 (en) | 1993-07-07 | 1993-07-07 | Engine air-fuel ratio control device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0727003A true JPH0727003A (en) | 1995-01-27 |
| JP3338907B2 JP3338907B2 (en) | 2002-10-28 |
Family
ID=16303021
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19314493A Expired - Fee Related JP3338907B2 (en) | 1993-07-07 | 1993-07-07 | Engine air-fuel ratio control device |
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| Country | Link |
|---|---|
| JP (1) | JP3338907B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013130069A (en) * | 2011-12-20 | 2013-07-04 | Osaka Gas Co Ltd | Engine system |
| JP2016017459A (en) * | 2014-07-08 | 2016-02-01 | 本田技研工業株式会社 | Control device for internal combustion engine |
-
1993
- 1993-07-07 JP JP19314493A patent/JP3338907B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013130069A (en) * | 2011-12-20 | 2013-07-04 | Osaka Gas Co Ltd | Engine system |
| JP2016017459A (en) * | 2014-07-08 | 2016-02-01 | 本田技研工業株式会社 | Control device for internal combustion engine |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3338907B2 (en) | 2002-10-28 |
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