AIR-FUEL RATIO CONTROLLER FOR V-ENGINE

PURPOSE:To improve the extent of responsiveness to control by changing an air-fuel ratio feedback constant on the basis of a phase difference in output of an air-fuel ratio sensor at each bank, in a device which divides a series of cylinders in the double bank into a multiple group by plural numbers of cylinders, and preforms fuel injection at each group. CONSTITUTION:In a V-type, 6-cylindered engine E, when an ignition sequence is set to such ones as cylinders 8a 8b 8c 8d 8e 8f, those of first, third, fifth cylinders 8a, 8c, 8e are installed in a left bank L and second, fourth, sixth cylinders 8b, 8d, 8f in a right bank R, respectively. Then, on the basis of each output of oxygen sensors 20L, 20R of these symmethrical banks L, R, a fuel injection quantity of each injector 9 of these first-third cylinders 8a-8c and fourth- sixth cylinders 8d-8f in each of A, B groups is controlled for feedback. At this time, a phase difference in each output of these oxygen sensors 20L, 20R is detected, and thereby a feedback control constant at time of the said feedback control is changed in a direction where this phase difference is decreased.