Air-fuel ratio control device of an internal combustion engine

摘要

An air-fuel ratio control device comprising an electric air bleed control valve which controls the amount of air fed into the fuel passage of the carburetor so that an air-fuel ratio becomes equal to the stoichiometric air-fuel ratio. The degree of opening of the air bleed control valve is increased as an electric current fed into the air bleed control valve is increased. Fuel vapor is fed into the intake passage from the canister. When the electric current fed into the air bleed control valve is increased and reaches a predetermined upper limit due to the supply of purge gas, the current fed into the air bleed control valve is instantaneously increased by a fixed amount.