Patent ID: 8486341

Claim:
An exhaust system comprising: a conduit configured to receive combustion products from an engine; an ammonia-to-NO x catalyst in fluid communication with the conduit, the ammonia-to-NO x catalyst for converting a first quantity of ammonia into NO x ; a first ammonia inlet disposed upstream of at least a portion of the ammonia-to-NO x catalyst and configured to receive a first quantity of ammonia from an ammonia source and deliver the first quantity of ammonia to the ammonia-to-NO x catalyst; an ammonia-SCR catalyst in fluid communication with and being disposed downstream from the ammonia-to-NO x catalyst, the ammonia-SCR catalyst for converting a second quantity of ammonia and NO x into nitrogen and water; and a second ammonia inlet disposed downstream of the ammonia-to-NO x catalyst and upstream of at least a portion of the ammonia-SCR catalyst and configured to receive ammonia from the ammonia source and deliver the second quantity of ammonia to the ammonia-SCR catalyst.