AIR-FUEL RATIO CONTROLLER FOR MULTICYLINDER ENGINE

PURPOSE:To sppress the hunting phenomenon accompanied by closed-loop control by installing each exhaust sensor into the exhaust systems for the cylinder groups divided into wo groups and correcting each integration signal into reverse phase in relation to the reversal timing of two integration signals on the basis of each exhaust sensor. CONSTITUTION:A multicylinder engine E is divided into the first and the second cylinder groups 1 and 2, and exhaust sensors 6 and 7 are installed into the exhaust systems 3 and 4 for the cylinder groups 1 and 2, respectively. Fuel is supplied into each group 1, 2 from a fuel feeding apparatus 8 through the first and the second air-fuel ratio adjusting means 9 and 10. Each air-fuel ratio adjusting means 9, 10 is controlled through an integration signal correcting means 13 by a closed-loop control means 11 according to the first and the second integration signals on the basis of each exhaust sensor 6, 7. An itegration signal correcting means 13 operates to correct at least one integrtion signal so that each direction of increase and decrease of the first and the second integation signals is set into reverse phase on the basis of the signal related to the reversal of each integration signal supplied from a reversal detecting means 12.