| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust emission control device having a process for adding a reducing agent to a nitrogen oxides absorbent and releasing nitrogen oxides so as to perform reduction, wherein a reducing agent is liquidized and retained in an exhaust-collector pipe when the temperature of the exhaust- collector pipe is lower than a predetermined temperature at the time of adding the reducing agent near the exhaust-collector pipe, and the liquidized reducing agent is whitened and released to the atmosphere when an internal combustion engine is next in a high load condition. SOLUTION: The temperature of catalyst inflow gas and the temperature inside an exhaust-collector pipe satisfy such a relationship that the temperature of the catalyst inflow gas is not less than the temperature inside the exhaust- collector pipe. When the temperature of the catalyst inflow gas is measured and is lower than a predetermined temperature, the temperature inside the exhaust-collector pipe is recognized as lower than a predetermined temperature. Then, addition of the reducing agent is restricted in the exhaust-collector pipe, so as to liquidize the reducing agent inside the exhaust-collector pipe.
|
