PURPOSE: To make it possible to protect a learned value from the effect of vapor evaporation of fuel etc. by prohibiting the learning of specified load range when a carburetor is in high temperature condition, in the case wherein an air-fuel ratio is controlled to a target value by controlling air-bleed quantity on the basis of learned value obtained by learning the operating condition of an engine.
CONSTITUTION: A learning means 5 is provided for learning the operating condition of an engine on the basis of exhaust gas component detected by an exhaust gas detecting means 4 at every load range specified according to the size of engine load quantity detected by a load quantity detecting means 3, and for calculating the learned value for each of specified load ranges. In addition, a learning selecting means 6 is provided for prohibiting the learning of all specified load ranges when the float chamber 2b of a carburetor 2 etc. are in high temperature condition and reversely for permitting its learning when they are not in high temperature condition. And air bleed quantity by which an air-fuel ratio comes to be a target value is calculated by means of operating means 7 according to the above-mentioned calculated learned value and an air bleed quantity control mechanism 2f is controlled through an output means 8 according to its calculated results.
ASANUMA MIKITO
ASADA YUKITOSHI
