Fuel injection control apparatus for internal combustion engine

Abstract

A fuel injection control apparatus for an internal combustion engine capable of making correctly or properly decision as to acceleration and deceleration of engine without fail on the basis of magnitude of change in the intake air quantity while excluding erroneous deceleration or acceleration decision due to overshoot or undershoot in the intake air quantity to thereby allow the exhaust gas air-fuel ratio to be maintained at least close to a stoichiometric ratio. The apparatus includes an electronic control unit comprised of a throttle-acceleration decision module, a fuel injection decreasing module and a fuel injection increasing module. When acceleration is determined by the throttle-acceleration decision module, a deceleration decision reference value used by the fuel injection decreasing module is set to a value greater than a normal value for a predetermined period after the decision of acceleration, while when deceleration is determined, an acceleration decision reference value for the fuel injection increasing module is set to a value greater than a normal value for a predetermined period after the decision of deceleration. The acceleration decision reference value and the deceleration reference value are compared with magnitude of change in the amount of intake air by the fuel increasing module and the fuel decreasing means for deciding the acceleration and the deceleration, respectively.