| 摘要 |
PROBLEM TO BE SOLVED: To provide an air-fuel ratio control device of an internal combustion engine, surely avoiding interference of the air-fuel ratio feedback control based on the upstream side air-fuel ratio sensor output value upstream from a catalyst with the air-fuel ratio feedback control based on the downstream side air-fuel ratio sensor output value downstream from the catalyst. SOLUTION: In this device, a value based on the upstream side air-fuel ratio sensor output value is processed by a band-pass filter A14 (BPF, passing permission frequency:ω1 toω2) and a high-path filter A12 (HPF, passing permission frequency:ω2 or more), and the filtered values are input to a P controller not conducting integration processing to thereby perform the fuel injection quantity correction by the main feedback control. A value based on the downstream side air-fuel ratio sensor output value is processed by a low-pass filter A7 (LPF, passing permission frequency:ω1 or less) and the obtained value is input to a PI controller not conducting differential processing to thereby perform the fuel injection quantity correction by the sub-feedback control. COPYRIGHT: (C)2006,JPO&NCIPI
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