Method and system for improving accuracy of correction of fuel quantity at the time when recirculation valve is opened

A method for improving accuracy of correction of fuel quantity at a time when a recirculation valve (RCV) is opened, the method comprising the steps of:

• correcting injection amount of fuel based on consideration factors when the RCV is operated to be opened,
• wherein the consideration factors comprise:
• property values of a flow path of the RCV, the flow path being mounted to an intake pipe to connect between a front end of a compressor close to atmosphere and a rear end of the compressor adjacent to combustion chambers;
• a first calculation value obtained by calculating an amount of air to be introduced into the combustion chambers after circulating from the flow path of the RCV to the intake pipe;
• and
• a second calculation value obtained by calculating an amount of hydrocarbon to be introduced into the flow path of the RCV by purging evaporative gas,
• wherein the property values of the flow path of the RCV comprise concentration of hydrocarbon contained in circulative intake air circulated to the intake pipe, and the concentration of hydrocarbon is calculated based on a spread/delay model,
• wherein the spread/delay model divides the flow path of the RCV into a predetermined number of cells,
• wherein among the predetermined number of cells, a first cell corresponds to an inlet of the flow path of the RCV and a last cell corresponds to an outlet of the flow path of the RCV, and
• wherein the spread/delay model is constructed by modeling spread and delay of gas introduced into the flow path of the RCV assuming that cells of the predetermined number of cells shift in a sampling time.