Method for determining the fullness or quality of a catalytic converter that stores gases

• US 6,240,722 B1
• Filed: 02/12/1999
• Issued: 06/05/2001
• Est. Priority Date: 02/13/1998
• Status: Expired due to Term

• Current Assignee: Daimler AG (Mercedes-Benz Group AG)
• Original Assignee: Daimler Chrysler Company LLC (Stellantis NV)
• Inventors: Knezevic, Aleksandar, Moos, Ralf, Busch, Michael-Rainer, Plog, Carsten
• Primary Examiner(s): Walberg, Teresa
• Assistant Examiner(s): DAHBOUR, HENRY
• Application Number:
  US09/248,997
• Time in Patent Office: 844 Days
• Field of Search: 602/74, 602/76, 602/77, 602/85, 602/86, 602/90, 603/03
• US Class Current: 60/277
• CPC Class Codes: B01D 53/9495 Controlling the catalytic process
• CPC Class Codes: F01N 11/002 the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus
• CPC Class Codes: F01N 2560/12 Other sensor principles, e.g. using electro conductivity of substrate or radio frequency
• CPC Class Codes: F01N 3/0807 by using absorbents or adsorbents
• CPC Class Codes: F01N 3/0814 combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts
• CPC Class Codes: F01N 3/0842 Nitrogen oxides
• CPC Class Codes: F01N 3/0864 Oxygen
• CPC Class Codes: F01N 3/0871 Regulation of absorbents or adsorbents, e.g. purging by electrically controlling the supply of combustible mixture or its constituents only F02D41/0235
• CPC Class Codes: F02D 2200/0806 NOx storage amount, i.e. amount of NOx stored on NOx trap
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A method for determining the fullness or the quality of a catalytic converter that stores gases in a storage medium includes the steps of measuring a change in at least one physical property of the storage medium that changes with the storage process, and determining the fullness or the quality of the catalytic converter.

Claims

1. A method for determining a fullness or quality of a catalytic converter situated in an exhaust gas stream and having a storage medium for storing gases, said method comprising:

measuring a chance in at least one physical property of the storage medium that changes with an amount of gas stored therein; and

determining a fullness or quality of the catalytic converter based on a result of said measurement;

wherein the at least one physical property is complex electrical impedance.

2. A method according to claim 1, wherein said measuring of the complex impedance is at one or more frequencies greater than 0 Hz.

3. A method according to claim 1, wherein an upper limiting frequency is a wavelength that is less than dimensions of a measuring arrangement.

4. A method according to claim 1, comprising:

providing an electrical device having at least two electrodes and a storage medium between the at least two electrodes; and

using said electrical device for measurement of the complex electrical impedance.

5. A method according to claim 4, wherein the at least two electrodes are located on an inside wall of a support structure.

6. A method according to claim 4, wherein:

at least two electrodes are located on an inside wall of a support structure; and

at least one layer of the storage medium is applied to the at least two electrodes.

7. A method according to claim 4, wherein:

at least one layer of the storage medium is applied to an inside wall of a support structure; and

the at least two electrodes are located on the storage medium.

8. A method according to claim 4, wherein the electrodes are located in an axial or a radial direction relative to a support structure.

9. A method according to claim 2, wherein the catalytic converter stores an exhaust gas component selected from the group consisting of nitrogen oxides, carbon monoxide, hydrocarbons, and combinations thereof.

10. A method for determining a fullness or quality of a catalytic converter situated in an exhaust gas stream and having a storage medium for storing gases, said method comprising:

measuring a chance in at least one physical property of the storage medium that changes with an amount of gas stored therein; and

determining a fullness or quality of the catalytic converter based on a result of said measurement;

wherein the at least one physical property is selected from the group consisting of the optical index of refraction, an optical absorption coefficient, and an optical reflection coefficient of the storage medium.

11. A method for determining a fullness or quality of a catalytic converter situated in an exhaust gas stream and having a storage medium for storing gases, said method comprising, measuring a change in at least one physical property of the storage medium that changes with an amount of gas stored therein, and, determining a fullness or quality of the catalytic converter based on a result of said measurement, wherein the at least one physical property is volume.

12. A method for determining a fullness or quality of a catalytic converter having a storage medium for storing gases flowing in an exhaust stream, comprising:

providing a measurement element in said exhaust stream, separate from said catalytic converter, and comprising a measurement medium similar to the storage medium;

measuring a change in at least one physical property of the measurement medium in the measurement element, that changes with an amount of gas stored therein; and

determining a fullness or quality of the catalytic converter based on said measuring.

13. A method according to claim 12, wherein the at least one physical property is complex electrical impedance of the medium.

14. A method according to claim 13, wherein said measuring of the complex impedance is at one or more frequencies greater than 0 Hz.

15. A method according to claim 14, wherein an upper limiting frequency is a wavelength that is less than dimensions of a measuring arrangement.

16. A method according to claim 13, wherein said step of measuring of the complex electrical impedance comprises providing a substrate having an electrode structure applied to one flat side and an electrical heater applied to the other flat side, with the medium being applied to the flat side having the electrode structure.

17. A method according to claim 16, wherein the substrate comprises at least one material selected from the group consisting of silicon, quartz, and ceramic.

18. A method according to claim 16, wherein the electrical heater comprises metal strips 100 nm to 50 μ

m thick.

19. A method according to claim 16, wherein the electrode structure comprises a metal and has a layer thickness between 100 nm and 50 μ

m.

20. A method according to claim 16, wherein the medium has a layer thickness between 100 nm and 1000 Am.

21. A method according to claim 12, wherein the at least one physical property is thermo electromotive force, wherein said step of measuring of the thermo electromotive force comprises providing a substrate having an electrical heater mounted on one flat side and at least two thermocouple pairs mounted on the other flat side of the medium.

22. A method according to claim 21, wherein the substrate comprises a material selected from the group consisting of silicon, quartz, and ceramic.

23. A method according to claim 21, wherein the electrical heater comprises metal strips having a layer thickness of 100 nm to 50 μ

m.

24. A method according to claim 12, wherein the at least one physical property is selected from the group consisting of an optical index of refraction, an optical absorption coefficient, and an optical reflection coefficient of the medium.

25. A method according to claim 12, wherein the at least one physical property is volume.