| 摘要 |
Using a gas detection voltage Vs output from a terminal CU, a determination is made at to whether, after startup of an air-fuel ratio detection apparatus ( 1 ), a full-range air-fuel ratio sensor ( 10 ) has reached a semi-activated state in which a determination can be made as to whether the air-fuel ratio is on the rich or lean side based on a change in a gas detection signal Vic. After determining that the sensor has reached the semi-activated state, the signal Vic is compared with a threshold to determine whether the air-fuel ratio is on the rich or lean side. In the apparatus ( 1 ), the potential difference between an outer pump electrode of a pump cell ( 14 ) and a reference electrode of an oxygen concentration measurement cell ( 24 ) is obtained via a first differential amplification circuit ( 53 ) as the gas detection signal Vic, the signal Vic being highly responsive to a change in air-fuel ratio of exhaust gas.
|
