| 摘要 |
PROBLEM TO BE SOLVED: To perform precise air-fuel ratio control with a single type air-fuel ratio sensor system by eliminating influence of hydrogen contained in exhaust gas. SOLUTION: An O2 sensor 13 is installed in the exhaust passage 14 of an internal combustion engine 1 in a position upstream of an exhaust gas purifying catalyst 15, and an ECU 10 conducts a feedback control of the air-fuel ratio of engine on the basis of the output of the sensor 13. The O2 sensor 13 is equipped with a catalyst for putting the exhaust gas reaching the sensor in equilibrium. The ECU 10 judges the ability of the sensor catalyst on the basis of the cyclic period of the feedback control and corrects the controlling characteristics of the feedback control in accordance with the ability of the sensor catalyst. This solves a problem, when sensor catalyst is provided to eliminate influence of hydrogen contained in the exhaust gas, that a deviation is generated in the air-fuel ratio control in association with a change in the ability of the sensor catalyst. |
