Method and apparatus for controlling urea injection amount of vehicle

Abstract

A method is provided for controlling a urea injection amount of a vehicle that controls urea ejection in consideration of a difference between an internal temperature change rate and a regeneration temperature of an SCR integral diesel particulate filter. The method includes: detecting a reproduction temperature rising rate when in a regeneration mode; stopping, if a reproduction temperature rising rate exceeds a predetermined first reference, ejection of urea, and controlling, if a reproduction temperature rising rate is less than a predetermined first reference, urea ejection; controlling, if a temperature decreasing rate according to urea ejection is less than a predetermined second reference while reproducing the filter, correction of an injection amount of urea; and controlling, if a difference between a target regeneration temperature and an actual regeneration temperature exceeds a predetermined third reference according to urea ejection while reproducing the filter, correction of an injection amount of urea.

Description

[0001] Cross References to Related Applications [0002] This application claims priority from Korean Patent Application No. 10-2012-0158624 filed on December 31, 2012, the entire contents of which are hereby incorporated by reference for all purposes. technical field [0003] The present invention relates to an apparatus and method for controlling the urea injection amount of a vehicle, which controls the urea injection of the vehicle in consideration of the difference in the internal temperature change rate and regeneration temperature of an SCR integrated diesel particulate filter installed in a diesel vehicle . Background technique [0004] To purify NO x , the SCR catalyst injects urea to a dosing module disposed at its front end, and obtains ammonia generated due to evaporation and decomposition of the injected urea. [0005] In order to achieve cost reduction, weight reduction, and efficient packaging of after-treatment devices, SCR integrated diesel particulate fil...

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Problems solved by technology

[0009] When regenerating the SCR integrated diesel particulate filter, due to urea injection, the regeneration temperature is destroyed by the increase in the heat capacity of the exhaust gas, so when increasing the urea injection amount to a predetermined amount or more, in order to ensure the target regeneration temperature, fuel injection The amount should be increased additionally thereby worsening the fuel consumption

[0010] Further, at the rear end of the diesel oxidation catalyst, as the HC slippage increases, the internal temperature of the SCR integrated diesel particulate filter increases, and when abnormal regeneration occurs, the temperature rises sharply, so the SCR Decomposition of the catalyst may be accelerated and the filter may be destroyed

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