Method for reducing urea deposits in an aftertreatment system

摘要

Various systems and methods are described for controlling a diesel aftertreatment system coupled to an exhaust system of an engine which includes a selective catalytic reduction (SCR) catalyst and a diesel particulate filter (PF). In one example, a threshold amount of urea injected to the SCR catalyst is adjusted based on an amount of soot generated by the engine and the total amount of urea injected to the SCR catalyst is limited by the threshold.

主权项

1. A method for an engine exhaust aftertreatment system, comprising:
in response to an accumulated amount of urea deposit in a selective catalytic reduction (SCR) catalyst being less than a threshold, injecting a decreased total amount of urea to the SCR catalyst between a first and second particulate filter (PF) regeneration during decreased soot production and injecting an increased total amount of urea to the SCR catalyst between the first and second PF regeneration during increased soot production; and in response to the accumulated amount of urea deposit in the SCR catalyst being greater than the threshold, adjusting regeneration of a PF based on the accumulated amount of urea deposit in the SCR catalyst to temporarily enable increased urea injection.