DIESEL PARTICULATE FILTER CONTROL

• US 20110131954A1
• Filed: 05/12/2010
• Published: 06/09/2011
• Est. Priority Date: 05/12/2010
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Parnin, Christopher
• Granted Patent: US 8,146,352 B2
• Time in Patent Office: Days
• US Class Current: 60/276
• CPC Class Codes: F01N 11/00 Monitoring or diagnostic devices for exhaust-gas treatment apparatus , e.g. for catalytic activity safety, indicating or supervising devices for internal combustion engines F02B77/08; testing of machines G01M13/00
• CPC Class Codes: F01N 2240/16 an electric heater, i.e. a resistance heater
• CPC Class Codes: F01N 2550/04 Filtering activity of particulate filters
• CPC Class Codes: F01N 2560/022 for measuring or detecting CO or CO2
• CPC Class Codes: F01N 3/027 using electric or magnetic heating means
• CPC Class Codes: F02D 41/029 the exhaust gas treating apparatus being a particulate filter
• CPC Class Codes: F02D 41/1452 the characteristics being a COx content or concentration
• CPC Class Codes: F02D 41/1466 the characteristics being a soot concentration or content
• CPC Class Codes: F02D 41/1494 Control of sensor heater
• CPC Class Codes: F02D 41/1495 Detection of abnormalities in the air/fuel ratio feedback system
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

Methods and systems are provided for managing particulate emissions in an engine including a particulate filter and a CO₂ sensor downstream of the filter. A CO₂ sensor may be used to infer the presence of particulate matter in the exhaust, downstream of the filter. By sensing particulate matter in the post-filter exhaust, filter degradation may be identified.

Claims

1. A method for monitoring particulate matter (PM) emissions from an engine exhaust including a particulate filter, comprising,

indicating filter degradation based on a CO₂ signature of oxidized, post-filter exhaust PMs.

2. The method of claim 1, wherein the CO₂ signature is based on a CO₂ level estimated by a CO₂ sensor positioned downstream of the filter.

3. The method of claim 2, wherein the exhaust PMs are oxidized on a substrate upstream of the CO₂ sensor.

4. The method of claim 3, wherein oxidizing exhaust PMs on the substrate includes operating a substrate heater to heat the substrate, and oxidizing exhaust PMs on the heated substrate using oxygen from exhaust gas.

5. The method of claim 2, wherein the CO₂ signature includes an estimated CO₂ level that is generated during a filter storing operation.

6. The method of claim 5, further comprising, initiating filter regeneration in response to the CO₂ level being higher than a threshold during filter storing.

7. The method of claim 5, wherein the indication includes, indicating filter degradation when the CO₂ level is greater than a threshold.

8. The method of claim 5, wherein the indication includes, indicating degradation when the estimated CO₂ level is greater than an expected CO₂ level, the expected CO₂ level determined based on engine operating conditions.

9. The method of claim 7, wherein indicating degradation includes setting a diagnostic code.

10. A method of operating an engine exhaust system including a particulate filter comprising,

adjusting engine operation based on a CO₂ signature of oxidized, post-filter exhaust particulate matters (PMs).

11. The method of claim 10, wherein the engine is a gasoline engine, and wherein the CO₂ signature includes a CO₂ level of oxidized, post-filter exhaust particulate matters (PMs) estimated by a CO₂ sensor positioned downstream of the filter, and wherein the adjustment is performed during selected engine running conditions.

12. The method of claim 11, wherein performing the adjustment during selected engine running conditions includes,

during a first engine running condition, adjusting engine operation based on an exhaust CO₂ level estimated by the sensor;

and

during a second engine running condition different from the first engine running condition, adjusting engine operation based on the estimated CO₂ level of oxidized, post-filter exhaust particulate matters (PMs).

13. The method of claim 12, wherein the exhaust system includes a substrate upstream of the CO₂ sensor, and wherein during the first condition, the filter is storing and the substrate is not oxidizing and during the second condition, the filter is storing and the substrate is oxidizing.

14. The method of claim 13, wherein the substrate is oxidizing includes the substrate being heated by a substrate heater.

15. The method of claim 14, wherein the exhaust PMs are oxidized on the heated substrate using oxygen from exhaust gas.

16. The method of claim 12, wherein adjusting engine operation based on the CO₂ signature includes initiating filter regeneration when the estimated CO₂ level of oxidized, post-filter exhaust particulate matters is greater than a threshold.

17. The method of claim 16, further comprising, indicating filter degradation based on the CO₂ level of oxidized, post-filter exhaust PMs.

18. The method of claim 17, wherein the indication includes determining an expected CO₂ level based on engine operating conditions, comparing the expected CO₂ level to the estimated CO₂ level, and indicating filter degradation when the estimated CO₂ level is greater than the expected CO₂ level, wherein indicating filter degradation includes setting a diagnostic code.

19. (canceled)

20. An engine exhaust system, comprising:

a particulate filter;

a CO₂ sensor coupled downstream of the filter;

a substrate positioned upstream of the CO₂ sensor; and

a controller having instructions thereon to,

during filter storing,

heat the substrate;

estimate a CO₂ level corresponding to exhaust PMs oxidized on the heated substrate;

initiate filter regeneration based on the estimated CO₂ level; and

determine filter degradation based on the estimated CO₂ level.

21. The system of claim 20, wherein heating the substrate includes,

turning on a substrate heater when an exhaust gas temperature is below a threshold to electrically heat the substrate;

and

turning off the substrate heater when the exhaust gas temperature is above the threshold to non-electrically heat the substrate using heated exhaust gas.