Diagnostic program and equipment for oxidation capacity of diesel engine flue gas after treatment system

摘要

The invention provides a method for diagnosing the oxidation capacity of a diesel engine flue gas post-treatment system A selective NOx reduction catalyst has an outlet equipped with a HC unburned hydrocarbon sensitive ammonia sensor.According to the invention, a predetermined amount of fuel is injected into the engine after delay, the fuel does not participate in the combustion in the cylinder, and enters the post-processing system, in which a certain proportion of fuel is burned by oxidation. Measure the concentration value read by the ammonia sensor, After ensuring that there is no ammonia leakage downstream of the selective NOx reduction catalyst, it is determined that the hydrocarbon concentration in the post-treatment system is equal to the concentration value.When the hydrocarbon concentration value is lower than the threshold value, the oxidation capacity of the post-treatment system meets the requirements.Figure published with summary: Figure 2