Exhaust gas purification apparatus in internal combustion engine

摘要

An exhaust gas purification apparatus is provided for an internal combustion engine which comprises an intake passage means, an exhaust passage means, a catalyzer for exhaust gas purification which is coupled to an exhaust passage, and an external air introducing passage for introducing external air. The external air introducing passage is coupled to the exhaust passage on the upstream side of the catalyzer. A control valve is positioned in the external air introducing passage and a detecting device is coupled to said control valve for detecting a deceleration of the engine and for opening the control valve in response thereto. External air flows through the external air introducing passage and the control valve into the catalyzer for cooling said catalyzer.