DEVICE FOR CONTROLLING AIR FUEL RATIO FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To maintain purifying capacity of catalyst appropriate by quickly returning air fuel ratio feed back control while controlling disturbance and slippage of air fuel ratio in recovery from a fuel cut condition to a fuel injection condition. SOLUTION: An air fuel ratioλis close to a stoichiometric condition (theoretical air fuel ratio) of 14.7 during a short period of time (time t3-time t4) until air fuel ratio feed back control is executed after recovery form the fuel cut condition to the fuel injection condition due to increasing correction of fuel injection quantity by fuel quantity increasing control. Even if increasing correction quantity in the fuel quantity increasing control shifts a little bit from a target, influence on air fuel ratio right after execution of air fuel ratio feed back control is small by the increasing correction quantity of this fuel quantity increasing control as compared to a case of correcting fuel injection quantity TAU successively after recovery to air fuel ratio feed back. Emission is improved and stability in operation condition of an internal combustion engine is increased by controlling disturbance of air fuel ratio. COPYRIGHT: (C)2003,JPO