A method for controlling diesel engine emissions is disclosed. The diesel engine's exhaust system has a NO.sub.x oxidation catalyst, a diesel particulate filter (DPF), and a lean NO.sub.x trap (LNT). The DPF is monitored to determine the need for regeneration. The LNT is monitored to determine the need for regeneration or desulfurization. A fuel injector is used to inject fuel upstream of the LNT under certain conditions, and a bypass may be used to bypass exhaust around the oxidation catalyst to provide richer or hotter exhaust to the LNT.
Magdi K. Khair; Cynthia C. Webb; Gordon J. Bartley Christopher A. Sharp