The present application belongs to the field of
diesel engine post-
processing system control method, and provides a
diesel engine two-stage SCR post-
processing system and method, the
system comprising a front-stage SCR system, a high-pressure HC injection system, a DOC system, a DPF system and a rear-stage SCR system connected in sequence along an engine
turbine exhaust port; the present application uses a high-pressure HC
injector to provide the HC oxidant required for DPF active regeneration, and the engine does not need to perform far post-injection to provide HC, thereby avoiding HC poisoning caused by high HC passing through the front-stage SCR; the present application uses a high-pressure HC
injector to effectively improve the post-
processing temperature, promote the downstream SCR to quickly ignite, and ensure the
NOx conversion efficiency at low temperature; the present application does not need to add a close-coupled DOC at the front end of the front-stage SCR, and the front-stage SCR can quickly ignite; the present application effectively improves the SCR control precision and ensures the
NOx emission reduction efficiency.