Patent ID: 7162862
Filing Date: 2007-01-16
Classification: B01D,F01N,F02D,Y02T

Abstract:
1. An air-fuel ratio control apparatus for an internal combustion engine, comprising: estimation means for estimating, on the basis of an exhaust air-fuel ratio of exhaust gas flowing into an exhaust purifying catalyst unit disposed in an exhaust passage of the engine, an estimation value which is an emission of at least one specific component contained in exhaust gas flowing out of the exhaust purifying catalyst unit or at least one representative value indicating the state of the exhaust gas flowing out of the exhaust purifying catalyst unit; target setting means for setting a target state regarding the estimating value estimated by the estimation means; air-fuel ratio control means for controlling the air-fuel ratio of the engine in such a manner that the estimation value estimated by the estimation means reaches the target state set by the target setting means; and ignition timing control means for controlling ignition timing of the engine, wherein the estimation value is an estimation value after a predetermined period of time which indicates a predicted value that the emission or representative value assumes after elapse of the predetermined period of time, the air-fuel ratio control means has a function of arbitrarily controlling the opening of a throttle value for adjusting an intake air amount of the engine; and when the air-fuel ratio is controlled by use of the air-fuel ratio control means in such a manner that the estimation value after a predetermined period of time estimated by the estimation means reaches the predetermined target state, control for opening the throttle valve is delayed by the air-fuel ratio control means, and the ignition timing is advanced by the ignition timing control means.