DEVICE FOR ESTIMATING CONCENTRATION OF ALTERNATIVE FUEL, VEHICLE PROVIDED WITH SAME, AND METHOD FOR ESTIMATING CONCENTRATION OF ALTERNATIVE FUEL

摘要

An ECU (60), used in a two-wheeled motor vehicle (1), comprising an engine (E) in which blended fuel obtained by blending gasoline and ethanol is burned in a combustion chamber (23), and a fuel injection device for injecting a specified fuel injection amount which is set such that an air excess ratio in the combustion chamber (23) is a first specified value when the concentration of ethanol in the blended fuel is zero.  The ECU (60) performs an O2 feedback control on the basis of an O2 concentration obtained from an output from an O2 sensor.  The ECU (60) further calculates an actual fuel correction factor obtained by dividing a fuel injection amount after the O2 feedback control by the specified fuel injection amount, and estimates the above concentration on the basis of the actual fuel correction factor and the first specified value stored in the ECU (60).