| 摘要 |
PROBLEM TO BE SOLVED: To enhance the sequential identification accuracy while suppressing the deterioration of emission when sequentially identifying a parameter of a plant model simulating a control object in feedback control in an air-fuel ratio control device for executing main feedback control and sub-feedback control by arranging an exhaust gas sensor on each of the upstream side and downstream side of a catalyst. SOLUTION: When sequentially identifying a parameter of a plant model simulating a control object in sub-feedback control, repetitive oscillation is made in which an upstream side targetϕ(a target air-fuel ratio on a catalyst upstream side) and upstream side detectionϕ(a detected air-fuel ratio of an upstream side exhaust gas sensor) are set to a rich state (or lean state) for a predetermined period from a stoichiometric state, returned to the stoichiometric state for a predetermined period, then set to a lean state (or rich state) for a predetermined period and again returned to the stoichiometric state for a predetermined period repeatedly, where "ϕ" indicates a fuel excess ratio (a reciprocal of an air excess ratioλ). COPYRIGHT: (C)2008,JPO&INPIT
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