| 摘要 |
PURPOSE:To improve the accuracy of air-fuel ratio detection by correcting the output level of an oxygen concentration sensor according to a correcting value when the oxygen concentration in exhaust gas is detected. CONSTITUTION:Both ends of a current detection resistance 23 are output terminals as the oxygen concentration sensor and connected to a control circuit 24 composed of a microcomputer. Fuel which is N (N>1 or 1>N/0) times as much as when the when output level of the oxygen concentration sensor is at a reference is supplied to an engine and the output level of the oxygen concentration sensor at this time is detected to easily obtain the difference in the gradient of characteristics from desired output characteristics as the correcting value for the output characteristics of the oxygen concentration sensor. Therefore, when the oxygen concentration in the exhaust gas is detected, the output level of the oxygen concentration sensor is corrected according to the correcting value to compensate variance of the oxygen concentration sensor in a rich and a lean range, thereby improving the accuracy of the air fuel ratio detection. |
