Secondary air supply system for internal combustion engines

摘要

A non-return air flow system for supplying secondary air into the exhaust system of internal combustion engines by utilizing pulsating flow of exhaust gases in the exhaust system, wherein the critical valve opening pressure for a check valve incorporated in the non-return system is varied in accordance with intake air flow rate of the engine so that supply of secondary air is effected in proportion to air intake of the engine.