A method for improving a purge conversion efficiency of a Lean NOx Trap coupled downstream of a lean-burn internal combustion engine is presented. This method proposes adjusting the purge air-fuel ratio of the device based on its temperature. According to the proposed method, a less rich air-fuel ratio...http://www.google.co.uk/patents/US6553757?utm_source=gb-gplus-sharePatent US6553757 - NOx purge air/fuel ratio selection
