| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust emission control system to assist a drive force by a motor, properly execute shifting to reduction rich in control of the air-fuel ratio of an internal combustion engine having an NOx purifying device and provide excellent exhaust gas characteristics by maintaining NOx absorption capacity of the NOx purifying device. SOLUTION: When a condition to stop an engine is established, it is discriminated at steps S12 and S13 whether the engine is in leans operation that an air fuel ratio is set to the lean side from a theoretical air-fuel ratio. Shifting to NOx reduction rich is executed at steps S14 and S15 during a shifting to rich time TRIII when an engine is under lean operation, and thereafter, the engine is actually stopped at S18. |
