| 摘要 |
The present invention aims at executing an air-fuel ratio feedback control making use of a wide range air-fuel ratio sensor, such that the purifying performance of an exhaust gas purification catalytic converter is exhibited to the utmost. To this end, fuel is injected from a fuel injection valve by establishing a fuel injection quantity, in consideration of a perturbation control constant for oscillating the air-fuel ratio at a predetermined period with a predetermined amplitude. Thus, even when the air-fuel ratio feedback control is executed making use of the detected result of the wide range air-fuel ratio sensor, it becomes possible to conduct a so-called perturbation control in which the air-fuel ratio of exhaust gas at the inlet portion of the exhaust gas purification catalytic converter is oscillated at a predetermined period with a predetermined amplitude. As a result, there can be effectively caused the adsorption and desorption of oxygen molecules onto and from the surface of the exhaust gas purification catalytic converter, so that the purifying performance of the catalytic converter can be remarkably improved.
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