Patent ID: 7941264
Filing Date: 2011-05-10
Classification: F02D,F02M,Y02T

Abstract:
1. A fuel supply device for a flexible-fuel internal combustion engine, comprising: a main passage through which a fuel pump pumps fuel from a fuel tank to a delivery pipe to which an injector is connected; a return passage through which fuel is returned from the delivery pipe to the fuel tank; a learning section that executes a concentration learning process in which a concentration of alcohol contained in fuel in the fuel tank is learned as a concentration learned value through an air-fuel ratio feedback control based on an oxygen concentration detected by an oxygen concentration sensor provided in an exhaust passage; a refueling operation detection section that detects whether a refueling operation has been performed for the fuel tank; and a return process control section that, when the refueling operation detection section detects that the refueling operation has been performed, executes a return suppression process to prevent fuel in the delivery pipe from returning to the fuel tank through the return passage for a predetermined period before the learning section starts the air-fuel ratio feedback control, and the return process control section executes a compulsory return process in which fuel in the delivery pipe is compulsorily returned to the fuel tank through the return passage after the air-fuel ratio feedback control is started.