AIR/FUEL RATIO CONTROLLER FOR MULTI-CYLINDER ENGINE

PURPOSE:To suppress the hunting and to improve the control accuracy by performing control such cylinder group as the closed-loop control is stopped through an open-loop control signal having the opposite phase from such cylinder group as the closed-loop control is executed. CONSTITUTION:Exhaust sensors 6, 7 are arranged respectively in the exhaust systems 3, 4 of the first and second cylinder groups 1, 2. Changeover control means 15 will perform the closed-loop control of the first air/fuel ratio regulating means 9 on the basis of the output from the first exhaust sensor 6 and the closed-loop control of the second air/fuel ratio regulating means 10 on the basis of the output from the second exhaust sensor 7 alternately. While the opposite phase control is performed for the first or second air/fuel ratio regulating means 9, 10 where the closed-loop control is stopped with correspondence to the first or second open-loop control signal. Consequently, the hunting can be eliminated resulting in improvement of the control accuracy.