FUEL-INJECTION-QUANTITY CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

The disclosed fuel-injection-quantity control device calculates (step 1140) a time integral value (SDVoxslow) by means of integrating the value of the deviation (DVoxslow) that is between the detected value (Voxs) by a downstream air-fuel ratio sensor disposed downstream of a catalyst and a downstream target value (Voxsref) and that is multiplied by a predetermined adjustment gain (K), and records (step 1165) the time integral value (SDVoxslow) as a sub-FB learning value (KSFBg). The device sets (steps 1125 through 1135) the aforementioned adjustment gain (K) in the case that the sub-FB learning value increases and the aforementioned adjustment gain (K) in the case that the sub-FB learning value decreases to different values in a manner so that the absolute value of the difference between the magnitude of the rate of increase of the sub-FB learning value and the magnitude of the rate of decrease of the sub-FB learning value is reduced. The control device determines that the sub-FB learning value has converged when the sub-FB learning value is, for at least a predetermined time period, present between a minimum value that is a predetermined value subtracted from a determination reference value and a maximum value that is a predetermined value added to the determination reference value in response to the center of fluctuation of the sub-FB learning value.