Air intake side secondary air supply system for an internal combustion engine with an improved operation under a small intake air amount

摘要

An air intake side secondary air supply system for an internal combustion engine is provided with a device for restricting the amount of the secondary air flowing through an air intake side secondary air supply passage when an amount of an intake air of the engine is small. By the provision of the flow restriction device, the operating range of an open-close valve or a linear type solenoid valve which is provided for controlling the air intake side secondary air, in which range the linearity of the operation of the valve is good, can be always used. Thus, the accuracy of the air/fuel ratio control is improved especially when the amount of the intake air of the engine is small.