Reduction of NOx trap at engine shutoff

摘要

The reduction of a NOx trap upon engine shutdown is disclosed. One disclosed embodiment comprises adjusting a timing of creating a reductive environment in the exhaust conduit upstream of the lean NOx trap based upon the determined engine stop position. The creation of a reductive environment in the exhaust conduit upstream of the lean NOx trap may help to at least partially reactivate the lean NOx trap during engine shutoff.