Exhaust purification device of an engine

摘要

An exhaust purification device comprising a first catalyst and a second catalyst arranged in the engine exhaust passage downstream of the first catalyst. An exhaust control valve is arranged downstream of the second catalyst. When the reducing components in the exhaust gas should be mainly oxidized by the first catalyst, the exhaust control valve is substantially fully closed and auxiliary fuel is additionally injected into the combustion chamber. When the reducing components in the exhaust gas should be mainly oxidized by the second catalyst, the exhaust control valve is fully opened and injection of auxiliary fuel is stopped.