EXHAUST EMISSION CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To remarkably reduce an amount of unburnt HC discharged into the atmosphere during starting of an engine and warming up operation. SOLUTION: An expansion chamber 20 is provided in each branch pipe 19a of an exhaust manifold 19. An exhaust control valve 24 is disposed in an exhaust pipe 23. During starting of an engine and warming up operation, the exhaust control valve 24 is approximately fully closed and an injection amount of main fuel is increased to a value higher than an optimum amount during full opening of the exhaust control valve and auxiliary fuel is additionally injected during an expansion stroke.