DETERMINATION OF DIESEL PARTICULATE FILTER LOAD UNDER BOTH TRANSIENT AND STEADY STATE DRIVE CYCLES

• US 20090151330A1
• Filed: 04/03/2008
• Published: 06/18/2009
• Est. Priority Date: 12/18/2007
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Opolsky, Norman Hiam, Van Nieuwstadt, Michiel J., Lyon, Peter Mitchell, Krenz, Edwin Allen, Gresens, Bradley D., Chamarthi, Gopal K., Waskiewicz, David Chester
• Granted Patent: US 8,051,645 B2
• Time in Patent Office: Days
• US Class Current: 60/286
• CPC Class Codes: F01N 9/002 of filter regeneration, e.g. detection of clogging
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

Systems and methods for updating the PF soot load of an engine are provided herein. In one embodiment, the method may include performing regeneration in response to both pressure-based measurements as well as estimated soot loading independent of the pressure-based measurements, where during conditions in which the pressure-based measurements may be inaccurate, the soot load is estimated based on operating conditions and previous pressure-based measurements that occurred during previous conditions in which the pressure-based measurements are more accurate. In this way, more continuous monitoring of particulate filter loading is provided, while taking advantage of pressure-based measurements from the most recent accurate reading, for example, and operating conditions that have transpired since such reading, including transient conditions. Thus, more appropriately timed regeneration may be provided.

Claims

1. A method for regenerating a particulate filter in an exhaust of a vehicle, the method comprising:

performing a regeneration of the particulate filter responsive to flow restriction induced pressure indications of a sensor, where during inaccurate sensor reading conditions, the regeneration is further responsive to a previous reading of the sensor during accurate sensor reading conditions and estimated soot loading based on operating conditions independent of the sensor after the previous reading.

2. The method of claim 1 where the sensor measures differential pressure across the particulate filter.

3. The method of claim 2 where the inaccurate sensor reading conditions include lower exhaust flow conditions.

4. The method of claim 3 where the accurate sensor reading conditions include higher exhaust flow conditions.

5. The method of claim 1 where the estimated soot loading is incrementally added to the previous reading until accurate sensor reading conditions occur.

6. The method of claim 1 where the sensor readings are taken at a slower sampling rate than the estimated soot loading is determined.

7. A method for regenerating a particulate filter in an exhaust of a vehicle, the method comprising:

performing a regeneration of the particulate filter responsive to flow restriction induced pressure indications of a sensor, where during lower flow and transient conditions;

the regeneration is further responsive to a previous reading of the sensor and estimated soot loading, the previous reading taken during higher flow conditions, and the estimated soot loading based on operating conditions independent of the sensor, the operating conditions independent of the sensor occurring during the lower flow and transient conditions.

8. The method of claim 7 where the sensor measures differential pressure across the particulate filter.

9. The method of claim 7 where pressure indications of the sensor include a first pressure sensor reading upstream of the filter and a second pressure sensor reading downstream of the filter.

10. The method of claim 7 where during higher flow conditions:

performing a regeneration of the particulate filter responsive to flow restriction induced pressure indications of the sensor independent from the estimated soot load.

11. The method of claim 10 further comprising regenerating the particulate filter by increasing exhaust heat of the engine via adjustment of engine operating conditions.

12. A method for regenerating a particulate filter in an exhaust of a vehicle, the method comprising:

determining a first soot loading responsive at least to differential pressure across the filter and measured by at least a pressure sensor;

determining an incremental estimated soot loading of the particulate filter responsive to a plurality of operating conditions and independent from the pressure sensor;

during higher flow conditions, performing regeneration responsive to the first soot loading and independent of the incremental estimated soot loading;

during lower flow and/or transient conditions, performing regeneration responsive to the last first soot loading reading taken before entering the lower flow and/or transient conditions, and further based on the incremental estimated soot loading.

13. The method of claim 12 where during the lower flow and/or transient conditions, regeneration is responsive to the last first soot loading reading and a plurality of further incremental estimated soot loadings successively added to the last reading.

14. The method of claim 13 further comprising clearing the incremental estimated soot loadings when entering the higher flow conditions.

15. The method of claim 14 further comprising adaptively updating the estimated soot loadings based on a soot loading indicated by the sensor after exiting the lower flow conditions and entering the higher flow conditions.