| 摘要 |
PROBLEM TO BE SOLVED: To perform adaptation of control variable in consideration of state where an air-fuel ratio sensor is degraded at low costs and precisely. SOLUTION: A new air-fuel ratio sensor is attached to an engine to judge whether an air fuel ratio is rich or lean from a detection signal of the air-fuel ratio sensor. Based on a sensor degradation status signal indicating the request of the degradation such as a condition equal to 100,000 km, a condition equal to 200,000 km, etc., time constants at rich time and at lean time are calculated, respectively. Based on the determination result whether it is rich or lean, either time constant at rich time or time constant at lean time is selected to correct the detection signal of the air-fuel ratio based on the selected time constant. The corrected detection signal is applied to an air-fuel ratio feed back control to simulate an engine operation in the degraded state. COPYRIGHT: (C)2005,JPO&NCIPI
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