Patent ID: 8156732
Filing Date: 2012-04-17
Classification: F01N,Y02T

Abstract:
1. An apparatus to regenerate an exhaust gas treatment device in exhaust gas stream receiving communication with an internal combustion engine, the apparatus comprising: an injector configured to inject reductant into the exhaust gas stream at a location between the internal combustion engine and the exhaust gas treatment device; and a controller module configured to direct the injector to inject the reductant into the exhaust gas stream over a plurality of rich intervals during a regeneration event on the exhaust gas treatment device to create a rich environment within the exhaust gas treatment device and to reduce the reductant injected into the exhaust gas stream over at least one lean interval between two of the plurality of rich intervals during the regeneration event on the exhaust gas treatment device to create a lean environment within the exhaust gas treatment device; wherein the controller module is configured to control the injection of reductant into the exhaust gas stream during the regeneration event according to at least one of first and second modes, the first mode comprising injecting a constant amount of reductant over each of the plurality of rich intervals with the length of at least two of the plurality of rich intervals being different, and the second mode comprising injecting an increased amount of reductant over each subsequent rich interval of the plurality of rich intervals with the length of each of the plurality of rich intervals being the same.