| 摘要 |
In an engine exhaust gas purification apparatus incorporating a LNT (lean NOx trap), during a NOx catalyst regeneration procedure for deoxidizing and removing accumulated sulfur from the LNT by producing a fuel-rich atmosphere in the exhaust system, the point at which to terminate the regeneration procedure is judged based on a difference between values of A/F ratio measured by sensors located respectively upstream and downstream from the LNT, with the regeneration being terminated when the difference falls below a predetermined threshold value.
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