Patent ID: 7865295

Claim:
A fuel injection controller of a flexible fuel internal combustion engine having a main passage through which fuel containing alcohol is fed from a fuel tank to a delivery pipe by a fuel pump, and a return passage through which the fuel is returned from the delivery pipe to the fuel tank, the controller comprising: an oxygen concentration sensor arranged in an exhaust passage of the engine; a correcting section that performs a concentration learning procedure in which a concentration of the alcohol of the fuel in the fuel tank is learned as a learned concentration value based on a detection value of the oxygen concentration sensor, the correcting section correcting a fuel injection amount of an injector connected to the delivery pipe in correspondence with the learned concentration value in such a manner that an air-fuel ratio corresponding to a stoichiometric air-fuel ratio is obtained; a refueling detecting section that detects that refueling has been carried out to the fuel tank; and a restricting section that performs a restricting procedure in which returning of the fuel from the delivery pipe to the fuel tank through the return passage is restricted on condition that the refueling detecting section has detected that the refueling has been performed.