Suction air control apparatus of internal combustion engine

Abstract

A suction air control apparatus of an internal combustion engine which is subjected to an after-start lean-burn control to be operated at a lean mixture ratio rather than a theoretical mixture ratio is provided. According to the apparatus, a smooth operation of the engine in a transitional state when the after-start lean-burn control is canceled is ensured. The apparatus comprises throttle opening degree control means for driving a throttle valve of a suction system to control a throttle opening degree to a target throttle opening degree set in accordance with an operation state of the engine for regulating amount of the suction air, after-start lean-burn control cancel discrimination means for discriminating cancellation of the after-start lean-burn control of the engine, steep acceleration discrimination means for discriminating whether an acceleration of a vehicle is a steep acceleration higher than a predetermined acceleration or not, and throttle opening degree correction means for correcting the target throttle opening degree to limit increase of the target throttle opening degree when the after-start lean-burn control cancel discrimination means discriminates cancellation of the after-start lean-burn control and the steep acceleration discrimination means discriminates the steep acceleration of the vehicle.