Patent ID: 6820595
Filing Date: 2004-11-23
Classification: F02D

Abstract:
A method of controlling a fuel injection amount of an internal combustion engine with respect to a suction stroke for which fuel is injected, comprising the steps of:estimating an operating state quantity of the engine to be established at the time of closing of an intake valve in the suction stroke in question, at a point in time prior to the time of closing of the intake valve; estimating an intake air amount in the suction stroke based on the estimated operating state quantity; calculating, as a pre-correction estimated necessary fuel amount, a provisional fuel amount that is needed along with the estimated intake air amount to achieve a target air/fuel ratio; calculating an actual necessary fuel amount as an amount of fuel actually needed for achieving the target air/fuel ratio in a previous suction stroke that precedes the suction stroke in question, based on a known value of the operating state quantity, at a point in time after closing of the intake valve in the previous suction stroke; calculating an actual intake fuel amount as an amount of fuel actually inducted into a cylinder of the engine during the previous suction stroke, based on at least an amount of fuel actually injected for the previous suction stroke; determining an excess or shortage of the fuel in the previous suction stroke based on the calculated actual necessary fuel amount and the calculated actual intake fuel amount, and calculating a fuel feedback correction amount corresponding to the determined excess or shortage of the fuel; calculating a normal estimated necessary fuel amount by correcting the pre-correction estimated necessary fuel amount with the calculated fuel feedback correction amount; calculating a fuel injection amount based on at least the calculated normal estimated necessary fuel amount; and injecting the fuel having the calculated fuel injection amount for the suction stroke in question, at a point in time before the time of closing of the intake valve in the suction stroke.