| 摘要 |
PROBLEM TO BE SOLVED: To improve accuracy of air-fuel ratio control by calculating amplitude from target output of sensor output and a period that the sensor output is returned to the target output whenever the output of an air-fuel ratio sensor is reversed with respect to the target output while executing air-fuel ratio feedback control, and correcting the output of the air-fuel ratio sensor. SOLUTION: An A/F sensor 45 for detecting an air-fuel ratio is arranged on an exhaust pipe 34, and a catalytic converter 38 and an O2 sensor 46 are arranged in an exhaust system further downstream from the A/F sensor 45. Then, air-fuel ratio feedback control by the A/F sensor 45 is executed under the control of an ECU 70. That is, while the air-fuel ratio feedback control is executed, amplitude from the target output of the output of air-fuel ratio sensor and a period when the output of the air-fuel sensor is returned to the target output after being intersected the target output, are calculated whenever the output of the air-fuel ratio sensor is reversed with respect to the target output. Then, the output voltage of the A/F sensor 45 found out in main air-fuel ratio feedback control is corrected on the basis of these amplitude and period. |
