Patent attributes
An estimation apparatus includes: a learning prohibition unit, configured to prohibit a learning unit from executing a learning control and retain a learning value, which is set just before prohibiting, as a fixed learning value which is a fixed value, when the fuel component amount estimation condition is satisfied; an air-fuel ratio correction amount computation unit, configured to compute a correction amount of the air-fuel ratio based on the feedback correction value and the fixed learning value, when the fuel component amount estimation condition is satisfied; an injection correction value change rate computation unit, configured to compute a change rate of the correction amount; an alcohol component correction value computation unit, configured to compute an alcohol component correction value based on the change rate; and an alcohol component amount estimation unit, configured to estimate an alcohol component amount in fuel based on the alcohol component correction value.
