EXHAUST EMISSION CONTROL DEVICE OF INTERNAL COMBUSTION ENGINE

摘要

An exhaust control valve (24) is arranged in an exhaust pipe (22) of an internal combustion engine. At the time of engine startup and warmup operation, the exhaust control valve (24) is substantially fully closed, the amount of injection of main fuel is increased from the optimum amount of injection at the time when the exhaust control valve is fully opened, auxiliary fuel is additionally injected during the expansion stroke, and thereby the unburned hydrocarbons exhausted into the atmosphere is greatly reduced at the time of engine startup and warmup operation.