Secondary air supply system for the exhaust system of an internal combustion engine

摘要

A secondary air supply system for the exhaust system of an internal combustion engine having a catalytic converter with a three-way catalyst, having an air control valve which selectively supplies a part of compressed air to the exhaust system while relieving the rest of the air to the atmosphere, wherein the air control valve has a valve element balanced by oppositely acting springs to a neutral position where it supplies a predetermined amount of secondary air necessary to provide stoichiometric exhaust gases at a standard flow of exhaust gases and is shifted to opposite sides of the neutral position in accordance with oscillation of feedback control of the air/fuel ratio of exhaust gases.