| 摘要 |
PURPOSE:To prevent hunting by calculating the primary lag and dead time of an air fuel ratio feedback control system provided with a lean sensor and making characteristic processing to the air fuel ratio set value by means of the calculated primary lag and dead time, in order to be made to be the aimed value. CONSTITUTION:On the basis of intake air flow Q and engine speed N, an air fuel ratio set value calculating means 11 reads out the set value of air fuel ratio according to the operating state, a dead time calculating means 17 reads out dead time of an air fuel ratio feedback control system and a primary lag time constant calculating means 18 reads out the primary lag time constant of the air fuel ratio feedback control system respectively from memory maps. The set value from the air fuel ratio set value calculating means 11 is, after being subjected to characteristic processing at a dead time processing means 19 and a primary lag processing means 20, output as the aimed value of air fuel ratio of an arithmometor 15. And according to deviation between the aimed value and the detected value of a lean sensor 5, a feedback control correction factor calculating means 16 outputs a feedback control correction factor to a multiplicator 13.
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