Emission control system for reducing nitrogen oxide discharging from exhaust gas of diesel engine of vehicle, has determining section determining whether regeneration control is completed based air-fuel ratios of exhaust gas

摘要

The system (1) has a catalytic converter section (5) arranged in an exhaust gas passage (4) of an internal combustion engine i.e. diesel engine (2), to occlude and reduce nitrogen oxide. A determining section determines whether a regeneration control is completed by a regeneration portion based on an air-fuel ratio of exhaust gas flowing upstream to the converter section and another air-fuel ratio of the exhaust gas flowing downstream to the converter section, where the latter air-fuel ratio is corrected by a correction portion during grease control. The emission control system has an estimation portion estimating hydrogen quantity based on carbon monoxide quantity and hydrocarbon quantity.