ENGINE CONTROL DEVICE

• Main Author: MIZOGUCHI HIROAKI
• Format: Patent
• Language: English; Japanese
• Published: 17.08.2017
• Subjects: BLASTING; COMBUSTION ENGINES; CONTROLLING COMBUSTION ENGINES; HEATING; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS; LIGHTING; MECHANICAL ENGINEERING; WEAPONS

PROBLEM TO BE SOLVED: To finish the learning of an air-fuel ratio learning value in an early stage, and to enhance the accuracy of the air-fuel ratio learning value, in an engine system which performs air-fuel ratio feedback control for making an actual air-fuel ratio approximate a stoichiometric air-fuel ratio during stoichiometric combustion, and performs air-fuel ratio feedforward control by using the air-fuel ratio learning value which is learnt during the feedback control at lean combustion.SOLUTION: An intake air amount (10 g/s) at lean combustion is calculated on the basis of current required torque (100 Nm) and an engine rotational speed (1,500 rpm), and a learning region is switched from a learning region (learning region (ii)) to which a current intake air amount (6 g/s) belongs to a learning region (learning region (iv)) to which the intake air amount (10 g/s) belongs. Since the intake air amount is increased, a fuel injection amount is also increased in order to hold stoichiometric combustion, and ignition timing is retarded according to an increase amount of the intake air amount in order to hold the current required torque (100 Nm).SELECTED DRAWING: Figure 5 【課題】ストイキ燃焼中には実空燃比をストイキに近づける空燃比フィードバック制御を行い、リーン燃焼中には当該フィードバック制御中に学習した空燃比学習値を用いて空燃比フィードフォワード制御を行うエンジンシステムにおいて、当該空燃比学習値の学習を早期に完了させると共に、当該空燃比学習値の精度を高める。【解決手段】現在の要求トルク（１００Ｎｍ）とエンジン回転速度（１５００ｒｐｍ）とに基づいてリーン燃焼になった際の吸入空気量（１０ｇ／ｓ）を算出し、現在の吸入空気量（６ｇ／ｓ）が属する学習領域（学習領域(ii)）から、この吸入空気量（１０ｇ／ｓ）の属する学習領域（学習領域(iv)）に切り替える。吸入空気量が増やされるのでストイキ燃焼を保持すべく燃料噴射量も増やし、現在の要求トルク（１００Ｎｍ）を保持すべく吸入空気量の増量分に応じて点火時期を遅角させる。【選択図】図５