Patent attributes
An evaporated fuel gas concentration learning section A8 renews an evaporated fuel gas concentration learning value based on a feedback correction amount FAF. An estimated purge rate calculating section A9 estimates, a flow of an evaporated fuel gas introduced into a combustion chamber based on a flow KP of an evaporated fuel gas passing through a purge control valve in consideration of a transportation delay time duration and a behavior of the evaporated fuel gas. An instructed injection amount determining section A10 calculates a purge correction amount based on the evaporated fuel gas concentration learning value and the estimated purge flow. An evaporated fuel gas purge stop timing adjusting section A11, at a purge control valve closing instruction timing, corrects the feedback correction amount to a base value and corrects the evaporated fuel gas concentration learning value so as to add, to the purge correction amount, an amount corresponding to an correction amount to correct the base injection amount provided by the feedback correction amount at a timing immediately before the feedback correction amount is corrected to the base value.
