| 摘要 |
PURPOSE:To improve an exhaust gas purification characteristic and a fuel consumption, by controlling an air-fuel ratio in a suction system to a leaner value as compared with a H range during running a vehicle at an L range, and reducing a secondary air quantity to be supplied to an exhaust system. CONSTITUTION:In a four-wheel-drive vehicle, a drive gear ratio of wheels is selected to an L range or a H range by a transfer. An air-fuel ratio of a mix ture gas is feedback controlled by a suction system air-fuel ratio control means B according to a detection signal from an air-fuel ratio sensor A. Further, a secondary air quantity to be supplied to an exhaust gas is feedback controlled by an exhaust system air-fuel ratio control means C according to the detection signal from the sensor A. When the L range is detected by an L range detecting means D, a setting means E sets an integration constant for driving the control means B to a value greater than that in the H range, and also sets an integra tion constant for driving the control means C to a value smaller than that in the H range.
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