| 摘要 |
The invention relates to an exhaust gas purification method and system for an internal combustion engine (99). The internal combustion engine (99) comprises a generator (51; 31) driven by said internal-combustion engine, a battery (38) charged with an electricity generation output from the generator (51; 31), and a NOx adsorption catalyst (18) placed in an exhaust gas passage. The catalyst (18) chemisorbs NOx in a state where the amount of an oxidizer is larger than that of a reducer in the stoichiometry relation of oxidoreduction between components contained in exhaust gas exhausted from said internal combustion engine (99) and catalytically reduces the adsorbed or absorbed NOx in a state where the amount of the reducer is at least equivalent to that of the oxidizer. When the time-elapsing deterioration of the NOx adsorption catalyst (18) reaches to a predetermined degree, the combustion condition of said internal combustion engine (99) is controlled at the stoichiometric air-fuel ratio or an excess fuel air-fuel ratio in a predetermined time period to reactivate the NOx adsorption catalyst (18) from the time-elapsing deterioration, and the increased proportion of the internal combustion engine output generated during the above time period is absorbed with said generator (51; 31). <IMAGE> |
