Patent ID: 7063080
Filing Date: 2006-06-20
Classification: F02D

Abstract:
1. A cylinder-by-cylinder air-fuel ratio controller for an internal combustion engine, comprising: an air-fuel ratio sensor detecting an air-fuel ratio of an exhaust gas, the air-fuel ratio sensor being disposed in a confluent portion into which the exhaust gas from each cylinder flows; an air-fuel ratio estimating means which estimates air-fuel ratios cylinder-by-cylinder based on an output of the air-fuel ratio sensor every air-fuel ratio detecting timing; an air-fuel ratio control means which controls the air-fuel ratio of each cylinder based on an estimated air-fuel ratios; and a determining means which determines a deviation of the air-fuel ratio detecting timing based on a dispersion of the estimated air-fuel ratio among the cylinders while the air-fuel ratio control means controls the air-fuel ratio.