FUEL INJECTION DEVICE

PROBLEM TO BE SOLVED: To provide a device can learn an injection amount of a fuel injection means by correcting the air-fuel ratio detected by an air-fuel ratio detection means in an exhaust system having the fuel injection means. SOLUTION: The difference between a convergence air-fuel ratio to which the air-fuel ratio detected by the air-fuel ratio detection means 7 will be converged if a sufficient time is elapsed after the start or completion of the fuel injection by the fuel injection means 3 and the air-fuel ratio detected by the air-fuel ratio detection means 7 beforehand (ΔA/F=air-fuel ratio (K/(t+a)2)). The difference is added to or deducted from the detected air-fuel ratio to obtain the air-fuel ratio in the period during which fuel is injected from the fuel injection means or the period during which the injection is stopped. Since the air-fuel ratio near the actual air-fuel ratio can be obtained over a wide operating range even in a limited Rich time or Lean time, the accuracy of learning of the fuel injection amount can be increased. COPYRIGHT: (C)2010,JPO&INPIT