Diagnostic system for monitoring catalyst performance

• US 6,803,236 B2
• Filed: 08/10/2001
• Issued: 10/12/2004
• Est. Priority Date: 08/10/2001
• Status: Expired due to Fees

• Current Assignee: Delphi Technologies, Inc. (Aptiv PLC)
• Original Assignee: Delphi Technologies, Inc. (Aptiv PLC)
• Inventors: Quelhas, Sergio, Bailey, Owen H., Schreurs, Bart, Balland, Jean J.
• Primary Examiner(s): Soderquist, Arlen
• Application Number:
  US09/927,718
• Publication Number:
  US 20030032188A1
• Time in Patent Office: 1,159 Days
• Field of Search: 436/37, 436/116, 436/118-119, 436/122, 436/127, 436/137, 436/149, 436/151, 602/74, 602/76, 422/83, 422/90, 422/94, 422/98
• US Class Current: 436/37
• CPC Class Codes: B01D 53/9431 Processes characterised by a specific device
• CPC Class Codes: B01D 53/9495 Controlling the catalytic process
• CPC Class Codes: F01N 11/007 the diagnostic devices measuring oxygen or air concentration downstream of the exhaust apparatus
• CPC Class Codes: F01N 13/009 having two or more separate purifying devices arranged in series
• CPC Class Codes: F01N 2390/02 using electric components only
• CPC Class Codes: F01N 2550/02 Catalytic activity of catalytic converters
• CPC Class Codes: F01N 2550/03 of sorbing activity of adsorbents or absorbents
• CPC Class Codes: F01N 2550/04 Filtering activity of particulate filters
• CPC Class Codes: F01N 2570/04 Sulfur or sulfur oxides
• CPC Class Codes: F01N 3/0814 combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts
• CPC Class Codes: F01N 3/0821 combined with particulate filters catalysed diesel particulate filters F01N3/035
• CPC Class Codes: F01N 3/0842 Nitrogen oxides
• CPC Class Codes: F02D 41/028 Desulfurisation of NOx traps or adsorbent
• CPC Class Codes: F02D 41/1439 characterised by the position of the sensor
• CPC Class Codes: F02D 41/1441 Plural sensors
• CPC Class Codes: F02D 41/1456 with sensor output signal being linear or quasi-linear with the concentration of oxygen
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y10T 436/177692 Oxides of nitrogen
• CPC Class Codes: Y10T 436/179228 Both nitrogen oxide and dioxide
• CPC Class Codes: Y10T 436/18 Sulfur containing
• CPC Class Codes: Y10T 436/186 : Sulfur dioxide
• CPC Class Codes: Y10T 436/188 : Total or elemental sulfur
• CPC Class Codes: Y10T 436/20 : Oxygen containing
• CPC Class Codes: Y10T 436/204998 : Inorganic carbon compounds
• CPC Class Codes: Y10T 436/205831 : Carbon monoxide only
• CPC Class Codes: Y10T 436/208339 : Fuel/air mixture or exhaust gas analysis

Abstract

A diagnostic system for monitoring catalyst performance in an exhaust system comprises a plurality of treatment devices catalytically treating an exhaust gas stream, and a plurality of gas sensors for monitoring the catalyst performance of the treatment devices to determine when sulfur poisoning occurs. An on-board diagnostic system receives signals from the gas sensors, and, based upon response time differentials between sensors, determines whether the treatment devices are experiencing sulfur poisoning.

Claims

1. A catalyst performance diagnostics system, comprising:

a plurality of treatment devices, wherein said plurality of treatment devices comprise a first treatment device, a second treatment device, and a third treatment device, and wherein at least two treatment devices comprise a nitrogen oxides adsorber material;

a plurality of gas sensors disposed in fluid communication with said plurality of treatment devices;

wherein said plurality of gas sensors comprise a first gas sensor disposed before said first treatment device, a second gas sensor disposed between said second treatment device and said third treatment device, and a third gas sensor disposed after said third treatment device, and

an on-board diagnostic system coupled to said plurality of gas sensors.

2. The catalyst performance diagnostics system of claim 1, wherein said plurality of gas sensors comprise a gas sensor disposed within a treatment device of said plurality of treatment devices.

3. The catalyst performance diagnostics system of claim 1, wherein said plurality of treatment devices comprise a particulate matter filter or an exhaust treatment device comprising a nitrogen oxides adsorber material disposed after said upstream gas sensor and disposed before another exhaust treatment device of said plurality of treatment devices.

4. The catalyst performance diagnostics system of claim 3, wherein said plurality of gas sensors comprises a downstream gas sensor disposed after said at least two treatment devices.

5. A method for monitoring catalyst performance, comprising:

introducing an exhaust gas stream into an exhaust system that includes a plurality of treatment devices and a plurality of gas sensors disposed in fluid communication with said plurality of treatment devices, wherein said plurality of treatment devices comprises a first treatment device, a second treatment device, and a third treatment device, and said plurality of gas sensors comprise a first gas sensor disposed before said first treatment device, a second gas sensor disposed between said second treatment device and said third treatment device, and a third gas sensor disposed after said third treatment device, and further wherein at least two treatment devices comprise a nitrogen oxides adsorber material;

monitoring said exhaust gas stream using said plurality of gas sensors;

passing said exhaust gas stream through said plurality of treatment devices;

measuring a first response time differential between said first gas sensor and said second gas sensor, and a second response time between said first gas sensor and said third gas sensor; and

desulfating said treatment devices based upon said first response time and said second response time.

6. The method of claim 5, further comprising monitoring said plurality of gas sensors using an on-board diagnostic system.

7. The method of claim 5, wherein said desulfating further comprises adjusting an air to fuel ratio to regenerate a catalyst material of one or more of said treatment devices.

8. The method of claim 5, wherein said measuring further comprises collecting a plurality of responses by an on-board diagnostic system, wherein said responses further comprise a response time differential between a first gas sensor and a second gas sensor, a response time differential between said second gas sensor and a third gas sensor, and a response time differential between said first gas sensor and said third gas sensor.

9. The method of claim 5, further comprising calculating a sulfur contamination index based upon said response time differentials between said plurality of gas sensors.

10. The method of claim 9, wherein said measuring further comprises measuring said response time differentials between said plurality of gas sensors to calculate a sulfur contamination index.

11. The method of claim 9, wherein said three sulfur contamination indices further comprise a first sulfur contamination index based on a first gas sensor and a third gas sensor, a second sulfur contamination index based on a second sensor and said third sensor, and a third contamination index based on said first sensor and said second sensor.

12. The method of claim 5, further comprising measuring a nitrogen oxide storage capacity of one or more of said treatment devices.

13. The method of claim 12, further comprising determining a nitrogen oxide conversion efficiency of said one or more treatment devices.

14. The method of claim 13, further comprising using said nitrogen oxide conversion efficiency of said one or more treatment devices to determine whether said treatment devices are experiencing sulfur poisoning.

15. A catalyst performance diagnostics system, comprising:

a plurality of treatment devices, wherein said plurality comprises a first treatment device, a second treatment device, and a third treatment device;

a plurality of gas sensors disposed in fluid communication with said plurality of treatment devices, wherein said plurality of gas sensors comprise a first gas sensor disposed before said first treatment device, a second gas sensor disposed between said second treatment device and said third treatment device, and a third gas sensor disposed after said third treatment device; and

an on-board diagnostic system coupled to said plurality of gas sensors.

16. The catalyst performance diagnostics system of claim 15, wherein at least one of said gas first sensor, said gas second sensor, and said third gas sensor is a NO_x sensor.

17. The catalyst performance diagnostics system of claim 16, wherein said first and said second gas sensors are stoichiometric switch sensors.

18. The catalyst performance diagnostics system of claim 16, wherein said third gas sensor is a NO_x sensor.