System and method for particulate filter regeneration

Abstract

The invention provides a system and method for particulate filter regeneration. Methods and systems are provided for regenerating an exhaust particulate filter based on a projected vehicle drive cycleand catalyst ammonia storage level. In one example, a method may include scheduling a PF regeneration during a regeneration window to maintain a threshold ammonia level in an exhaust catalyst, at theend of the drive cycle.

Description

technical field [0001] The present description generally relates to methods and systems for controlling a vehicle engine to perform regeneration of a particulate filter based on predicted vehicle drive cycles and catalyst ammonia storage levels. Background technique [0002] Emission control devices, such as particulate filters (PF) and selective catalytic reduction (SCR) catalysts, can reduce engine soot and NOx emissions by trapping soot particles and reducing NOx to nitrogen and water, respectively. In order to reduce NOx, a reducing agent such as ammonia needs to be present. The particulate filter may be regenerated during engine operation to reduce the amount of trapped particulate matter. Regeneration may be achieved by raising the temperature of the PF to a predetermined level, maintaining the temperature at the predetermined level, and ensuring that the exhaust gas entering the PF has a certain composition to combust or oxidize particulate matter. [0003] Various ...

AI Technical Summary

Problems solved by technology

If PF regeneration is scheduled to terminate at the end of the current drive cycle, during the immediately subsequent engine start, the amount of ammonia remaining in the SCR catalyst may be lower than desired, adversely affecting emission quality

Higher exhaust gas temperatures during PF regeneration may lead to increased urea injector temperature, which may lead to injector degradation

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