JPS6429649A - Individual cylinder air-fuel ratio controller for multicylinder engine - Google Patents

Abstract

PURPOSE:To improve the extent of control precision by discriminating the slippage of each air-fuel ratio in multiple cylinders, finding a correction value of each individual cylinder so as to correct this slippage, and correcting a fuel quantity to be subjected to feedback control of each cylinder according to this correction value. CONSTITUTION:A device 4 controls each fuel quantity to be fed to multiple cylinders independently with one another. And, device 3 compensates the fuel quantity for feedback so as to an air-fuel ratio to become the desired value on the basis of output of an exhaust sensor 1 installed in a converging part of exhaust pipes at each cylinder. In this case, slippage in the air-fuel ratio at each cylinder is discriminated by a device 2. And, on the basis of output of the device 2, a correction value is operated so as to correct the air-fuel ratio slippage at each cylinder by a device 5 and stored in memory. And, on the basis of output of the device 5, the fuel quantity to be feedback controlled at each individual cylinder is corrected. With this constitution, air-fuel ratio control by cylinders is highly accurately performed on the basis of a mean air-fuel ratio to be detected by the exhaust sensor 1.