Method and device pertaining to dosing unit of SCR system

Patent metadata

Field	Value
Publication number	US-9399940-B2
Application number	US-201113805024-A
Country	US
Kind code	B2
Filing date	Jun 20, 2011
Priority date	Jun 21, 2010
Publication date	Jul 26, 2016
Grant date	Jul 26, 2016

Abstract

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 (s 340 ) whether there is an undesired temperature level of the dosing unit ( 250 ). If one is found, removing (s 360 ) warmed reducing agent from the dosing unit ( 250 ) and supplying it to the exhaust duct ( 240 ). Calculating (s 350 ) 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.

First claim

The invention claimed is:

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.

2. The method according to claim 1 , wherein the engine ceases generating exhaust flow; and
said determination of whether there is said undesired temperature level is done after said cessation of said exhaust flow.

3. The method according to claim 1 , further comprising continuously cooling said dosing unit by a flow of said reducing agent to said dosing unit.

4. The method according to claim 1 , further comprising intermittently removing said reducing agent from said dosing unit by supplying said removed reducing agent to said exhaust duct.

5. The method according to claim 1 , wherein said undesired temperature level is within a predetermined range.

6. The method according to claim 1 , wherein said reducing agent is a urea-based reducing agent.

7. An electronic control unit of an SCR system for cleaning of exhaust gases from an engine wherein said SCR system comprises a dosing unit to supply a reducing agent to an exhaust duct of said engine, said electronic control unit of said SCR system being configured to:
continuously determine a prevailing temperature within said dosing unit in order to determine whether there is an undesired temperature level within said dosing unit;
determine whether there is said undesired temperature level within said dosing unit;
remove warmed reducing agent from said dosing unit and supply said removed reducing agent to said exhaust duct if said electronic control unit determines that said undesired temperature level of said dosing unit exists; and
calculate and remove from said dosing unit an amount of said reducing agent based on a prevailing temperature within said dosing unit or remove a predetermined amount in the form of all of said warmed reducing agent from the dosing unit and transferring said removed reducing agent to said exhaust duct,
wherein said removal of said reducing agent from said dosing unit comprises removing said reducing agent from said dosing unit by existing pressurisation of said reducing agent in said dosing unit.

8. The electronic control unit according to claim 7 , wherein said engine generates an exhaust flow when said engine is operating and ceases generating said exhaust flow when said engine is not operating; and
said determination of whether there is said undesired temperature level is performed after said cessation of said exhaust flow.

9. The electronic control unit according to claim 7 , wherein the electronic control unit is further configured to:
continuously cool said dosing unit by generating a flow of said reducing agent to said dosing unit.

10. The electronic control unit according to claim 7 , wherein said electronic control unit is further configured to intermittently remove said reducing agent from said dosing unit by supplying the removed dosing agent to said exhaust duct.

11. The electronic control unit according to claim 7 , wherein said undesired temperature level is within a predetermined range.

12. The electronic control unit according to claim 7 , wherein the electronic control unit is further configured to:
remove said reducing agent from said dosing unit by existing pressurisation of said reducing agent in said dosing unit.

13. A motor vehicle comprising the electronic control unit according to claim 7 .

14. A motor vehicle according to claim 13 , comprising one of a truck, bus or passenger car.

15. A non-transitory computer-readable medium on which is stored a computer program product pertaining to an SCR system for exhaust cleaning of an engine, wherein said computer program product comprises program code with program instructions for causing an electronic control unit to perform steps according to claim 1 or causing another computer connected to the electronic control unit to perform such steps when instructions in said code are run on said electronic control unit or on said computer, respectively.

16. The method according to claim 1 , wherein said undesired temperature level is within a range of 80-130 degrees Celsius.

17. The electronic control unit according to claim 7 , wherein said undesired temperature level is within a range of 80-130 degrees Celsius.

18. The electronic control unit according to claim 7 , wherein said dosing unit is at said exhaust duct where said dosing unit is heated.

19. The method according to claim 1 , wherein said SCR system further comprises a container supplying said reducing agent to said dosing unit and receiving said reducing agent from said dosing unit and said method further comprises returning a portion of said reducing agent to said container from said dosing unit to cool said dosing unit.

20. The electronic control unit according to claim 7 , wherein said SCR system further comprises a container supplying said reducing agent to said dosing unit and receiving said reducing agent from dosing unit and said electronic control unit is further configured to control operation of said dosing unit to regulate return of said reducing agent to said container from said dosing unit to cool said dosing unit.

21. The method according to claim 1 , wherein all of said warmed reducing agent in said dosing unit is transferred to said exhaust duct when said undesired temperature is found.

22. The electronic control unit of claim 7 , wherein the electronic control unit transfers all of said warmed reducing agent in the dosing unit to said exhaust duct based on a prevailing temperature within said dosing unit.

23. The method according to claim 1 , wherein the step of continuously determining a prevailing temperature within said dosing unit comprises:
at least one of:
detecting a prevailing temperature of the dosing unit by a first temperature sensor; and
detecting a prevailing temperature of the exhaust duct by a second temperature sensor.

24. The electronic control unit of claim 7 , wherein said electronic control unit of said SCR system being configured to continuously determine a prevailing temperature within said dosing unit comprises:
at least one of:
detecting a prevailing temperature of the dosing unit by a first temperat

Assignees

• Liljestrand Andreas
• Bremberg Per
• Arvidsson Daniel
• Scania Cv Ab

Inventors

• Liljestrand Andreas
• Bremberg Per
• Arvidsson Daniel

Classifications

• F01N2610/11

  the substance or part of the dosing system being cooled · CPC title

• F01N2610/146

  Control thereof, e.g. control of injectors or injection valves · CPC title

• F01N2610/10

  the substance being heated, e.g. by heating tank or supply line of the added substance · CPC title

• F01N11/00

  Monitoring or diagnostic devices for exhaust-gas treatment apparatus · CPC title

• F01N2900/0408

  using a feed-back loop · CPC title