Method for operating an SCR catalytic converter system which has a first SCR catalytic converter and a second SCR catalytic converter

Patent metadata

Field	Value
Publication number	US-10753255-B2
Application number	US-201816124476-A
Country	US
Kind code	B2
Filing date	Sep 7, 2018
Priority date	Sep 12, 2017
Publication date	Aug 25, 2020
Grant date	Aug 25, 2020

Abstract

A method ( 300 ) for operating an SCR catalytic converter system which has a first SCR catalytic converter ( 12 ) and a second SCR catalytic converter, characterized by a step of controlling ( 310 ) an NH 3 mass flow after the first SCR catalytic converter ( 12 ).

First claim

The invention claimed is:

1. A method ( 300 ) for operating an SCR catalytic converter system that has a first SCR catalytic converter ( 12 ) and a second SCR catalytic converter ( 13 ), the method comprising:
processing, by a first control system, a value ( 132 , 134 ) for an NH 3 filling level of the second SCR catalytic converter ( 13 ) in a manner that causes the first control system to control ( 310 ) an NH 3 mass flow after the first SCR catalytic converter ( 12 ); and
changing ( 320 ), by a controller output ( 108 , 109 ) of the first control system, a current model efficiency of a model of the second SCR catalytic converter ( 13 ),
wherein the first control system changes the current model efficiency in accordance with a difference between an actual value ( 100 ) of the NH 3 mass flow after the first SCR catalytic converter ( 12 ) and a corrected setpoint value ( 150 ) of the NH 3 mass flow after the first SCR catalytic converter ( 12 ).

2. The method ( 300 ) according to claim 1 , further comprising:
controlling ( 330 ), by a second control system ( 110 ), the NH 3 filling level of the second SCR catalytic converter ( 13 ) in a manner that causes the NH 3 filling level of the second SCR catalytic converter ( 13 ) to remain between a minimum NH 3 filling level ( 212 ) of the second SCR catalytic converter ( 13 ) and a maximum NH 3 filling level ( 214 ) of the second SCR catalytic converter ( 13 ).

3. The method ( 300 ) according to claim 2 , wherein the value ( 132 , 134 ) for an NH 3 filling level of the second SCR catalytic converter ( 13 ) is from the group consisting of a setpoint value ( 132 ) of the NH 3 filling level of the second SCR catalytic converter ( 13 ) and an actual value ( 134 ) of the NH 3 filling level of the second SCR catalytic converter ( 13 ).

4. The method ( 300 ) according to claim 2 , wherein when an NH 3 filling level of the first SCR catalytic converter ( 12 ) is at a maximum NH 3 filling level ( 206 ) of the first SCR catalytic converter ( 12 ), the second control system ( 110 ) adjusts the NH 3 filling level of the second SCR catalytic converter ( 13 ) to a filling level that is between the minimum NH 3 filling level ( 212 ) of the second SCR catalytic converter ( 13 ) and the maximum NH 3 filling level ( 214 ) of the second SCR catalytic converter ( 13 ).

5. The method ( 300 ) according to claim 4 , further comprising:
controlling ( 330 ), by the second control system ( 110 ), the NH 3 filling level of the first SCR catalytic converter ( 12 ) in a manner that causes the NH 3 filling level of the first SCR catalytic converter ( 12 ) to remain between a minimum NH 3 filling level ( 212 ) of the first SCR catalytic converter ( 12 ) and the maximum NH 3 filling level ( 214 ) of the first SCR catalytic converter ( 12 ).

6. The method ( 300 ) according to claim 1 , wherein the first control system adds an offset ( 146 ) to a multiplication product in a manner that creates the corrected setpoint value ( 150 ) of the NH 3 mass flow after the first SCR catalytic converter ( 12 ).

7. The method ( 300 ) according to claim 6 , wherein the first control system multiplies a setpoint value ( 101 ) of the NH 3 mass flow after the first SCR catalytic converter ( 12 ) by a multiplicative correction factor ( 142 ) in a manner that produces the multiplication product.

8. The method ( 300 ) according to claim 7 , wherein the setpoint value ( 101 ) of the NH 3 mass flow after the first SCR catalytic converter ( 12 ) is a product of an NOx mass flow ( 112 ) ahead of the second SCR catalytic converter ( 13 ) and a current model efficiency ( 114 ) of the second SCR catalytic converter ( 13 ).

9. The method ( 300 ) according to claim 7 , wherein the first control system selects the multiplicative correction factor ( 142 ) by a characteristic curve ( 140 ).

10. The method ( 300 ) according to claim 9 , wherein the first control system selects the offset ( 146 ) by another characteristic curve ( 144 ).

11. A non-transitory, machine-readable storage medium containing a computer program, the computer program when executed by the computer causes a computer to perform the method ( 300 ) according to claim 1 .

12. An electronic control device that is configured to operate an SCR catalytic converter system, the SCR catalytic converter system has a first SCR catalytic converter ( 12 ) and a second SCR catalytic converter ( 13 ), the electronic control device comprising:
a first control system configured to:
control ( 310 ) an NH 3 mass flow after the first SCR catalytic converter ( 12 ) by processing a value ( 132 , 134 ) for an NH 3 filling level of the second SCR catalytic converter ( 13 ),
output a controller output ( 108 , 109 ) that changes ( 320 ) a current model efficiency of a model of the second SCR catalytic converter ( 13 ), and
change the current model efficiency in accordance with a difference between an actual value ( 100 ) of the NH 3 mass flow after the first SCR catalytic converter ( 12 ) and a corrected setpoint value ( 150 ) of the NH 3 mass flow after the first SCR catalytic converter ( 12 ).

13. The electronic control device according to claim 12 , wherein the value ( 132 , 134 ) for an NH 3 filling level of the second SCR catalytic converter ( 13 ) is from the group consisting of a setpoint value ( 132 ) of the NH 3 filling level of the second SCR catalytic converter ( 13 ) and an actual value ( 134 ) of the NH 3 filling level of the second SCR catalytic converter ( 13 ).

14. The electronic control device according to claim 12 , further comprising:
a second control system ( 110 ) configured to control ( 330 ) the NH 3 filling level of the second SCR catalytic converter ( 13 ) causing the NH 3 filling level of the second SCR catalytic converter ( 13 ) to remain between a minimum NH 3 filling level ( 212 ) of the second SCR catalytic converter ( 13 ) and a maximum NH 3 filling level ( 214 ) of the second SCR catalytic converter ( 13 ).

15. The electronic control device according to claim 14 , wherein when an NH 3 filling level of the first SCR catalytic converter ( 12 ) is at a maximum NH 3 filling level ( 206 ) of the first SCR catalytic converter ( 12 ), the second control system ( 110 ) adjusts the NH 3 filling level of the second SCR catalytic converter ( 13 ) to a filling level that is between the minimum NH 3 filling level ( 212 ) of the second SCR catalytic converter ( 13 ) and the maximum NH 3 filling level ( 214 ) of the second SCR catalytic converter ( 13 ).

16. The electronic control device according to claim 14 , wherein the second control system ( 110 ) is configured to control ( 330 ) the NH 3 filling level of the first SCR catalytic converter ( 12 ) in a manner that causes the NH 3 filling level of the first SCR catalytic converter ( 12 ) to remain between a minimum NH 3 filling level ( 212 ) of the first SCR catalytic converter ( 12 ) and the maximum NH 3 filling level ( 214 ) of the first SCR catalytic converter ( 12 ).

Assignees

• Bosch Gmbh Robert

Inventors

• Schweizer Frank

Classifications

• Y02T10/12

  Improving ICE efficiencies · CPC title

• F01N2900/1622

  Catalyst reducing agent absorption capacity or consumption amount · CPC title

• F01N2560/026

  for measuring or detecting NOx · CPC title

• F01N3/2066

  Selective catalytic reduction [SCR] · CPC title

• F01N9/00

  Electrical control of exhaust gas treating apparatus (monitoring or diagnostic devices for exhaust-gas treatment apparatus F01N11/00; conjoint electrical control of two or more combustion engine functions F02D43/00) · CPC title