Air intake side secondary air supply system for an internal combustion engine

摘要

The so called air intake side secondary air supply system for an internal combustion engine includes first and second secondary air supply passages leading to an intake air passage on a downstream side of a throttle valve. The system is provided with a delay device in the second secondary air supply passage on an upstream side of an open/close valve disposed in the second secondary air supply passage, a pressure supply passage which provides communication between a pressure chamber of an air control valve disposed in the first secondary air supply passage and a part of the second secondary air supply passage between the delay device and the open/close valve, a second air supply delay means disposed in said pressure supply passage and a pressure control means for supplying a pressure for reducing the opening degree of the air control valve into said pressure supply passage during a predetermined operating condition of the engine.