Method and device pertaining to dosing unit of SCR system

摘要

A method pertaining to an SCR system for cleaning of exhaust gases from an engine including a dosing unit (250) to supply a reducing agent to an exhaust duct (240): Determining (s340) whether there is an undesired temperature level of the dosing unit (250). If one is found, removing (s360) warmed reducing agent from the dosing unit (250) and supplying it to the exhaust duct (240). Calculating (s350) and removing an amount of reducing agent based on a prevailing temperature of the dosing unit (250), or removing warmed reducing agent. Also a computer program product containing program code (P) for a computer (200; 210) for implementing the method. Also a device of an SCR system and a motor vehicle (100) which is equipped with the device are disclosed.

主权项

1. A method pertaining to an SCR system of an engine having an exhaust duct and the engine generates exhaust gases to the exhaust duct when the engine is operating, the system being configured and operable for cleaning of the exhaust gases from the engine;
the SCR system comprising a dosing unit to supply a reducing agent to said exhaust duct; the method comprising the steps of: continuously determining a prevailing temperature within said dosing unit in order to determine whether there is an undesired temperature level within said dosing unit; determining whether there is said undesired temperature level within said dosing unit; and removing warmed reducing agent from said dosing unit by supplying said removed reducing agent to said exhaust duct if said undesired temperature is found, said removal of said warmed reducing unit comprising: calculating and removing an amount of said reducing agent based on a prevailing temperature within said dosing unit or removing a predetermined amount comprised of all of said warmed reducing agent in said dosing unit and transferring said removed reducing agent from said dosing unit to said exhaust duct, wherein said step of removing said warmed reducing agent from said dosing unit comprises removing said warmed reducing agent from said dosing unit by existing pressurisation of said warmed reducing agent in said dosing unit.