| 摘要 |
<p>PURPOSE:To restrain discharge of CO and HC to the minimum at the time of deterioration of a catalytic converter arranged in an exhaust system of an internal combustion engine. CONSTITUTION:Proportional and integral (P paragraph, I paragraph) control of air-fuel ratio correction factor KO2 is carried out in accordance with output FVO2 of an O2 sensor arranged on the upstream side of a catalytic converter. The P paragraph control is carried out by delaying a specified period of time (T2, T4, T8, T10) from a reversal point of time (t1, t3, t7, t9) of the sensor output FVO2. At the time of detecting deterioration of the catalytic converter, this delay time is made shorter than before the detection of deterioration. Consequently, variation frequency (frequency of feedback control) of the correction factor KO2 becomes high, and performance of the catalytic converter is drawn out to the maximum.</p> |
