PARTICULATE FILTER REGENERATION IN AN ENGINE

• US 20110072793A1
• Filed: 11/02/2009
• Published: 03/31/2011
• Est. Priority Date: 09/29/2009
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Bidner, David Karl, Cunningham, Ralph Wayne
• Granted Patent: US 8,402,751 B2
• Time in Patent Office: Days
• US Class Current: 60/285
• CPC Class Codes: F01N 3/0233 periodically cleaning filter by blowing a gas through the filter in a direction opposite to exhaust flow, e.g. exposing filter to engine air intake
• CPC Class Codes: F01N 3/0238 for regenerating during engine standstill
• CPC Class Codes: F01N 9/002 of filter regeneration, e.g. detection of clogging
• CPC Class Codes: F02D 2200/0814 Oxygen storage amount
• CPC Class Codes: F02D 41/029 the exhaust gas treating apparatus being a particulate filter
• CPC Class Codes: F02D 41/0295 Control according to the amount of oxygen that is stored on the exhaust gas treating apparatus
• CPC Class Codes: F02D 41/042 for stopping the engine
• CPC Class Codes: F02D 41/062 for starting F02D41/061 takes precedence
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

Systems and methods for controlling regeneration of a particulate filter downstream of an engine in a vehicle are provided herein. One exemplary method includes, during an engine shutdown, increasing a throttle opening and regenerating a particulate filter downstream of a three-way catalyst. The method also includes, during an engine start following an engine shutdown, setting one or more engine parameters based on whether the particulate filter was regenerated during a last engine shutdown before the engine start.

Claims

1. A method for controlling a regeneration of a particulate filter downstream of an engine, comprising:

during an engine start, adjusting an engine parameter based on whether the particulate filter was regenerated during a last engine shutdown before the engine start.

2. The method of claim 1, further comprising during the engine start, regenerating the particulate filter downstream of a three-way catalyst, where adjusting the engine parameter includes increasing a throttle opening.

3. The method of claim 1, where during the engine start, adjusting the engine parameter includes setting an air-fuel ratio to be at a first air-fuel ratio if the particulate filter was regenerated during the last engine shutdown, and setting the air-fuel ratio to be at a second, less rich or more lean, air-fuel ratio if the particulate filter was not regenerated during the last engine shutdown.

4. The method of claim 1, where during the engine start, adjusting the engine parameter includes retarding a spark timing if the particulate filter was regenerated during the last engine shutdown.

5. The method of claim 1, where during the engine start, adjusting the engine parameter is further based on a duration of the regeneration during the last engine shutdown.

6. The method of claim 1, further comprising, during the engine start, adjusting one or more of an air-fuel ratio, a spark timing, an injection timing, and a throttle opening further based on one or more of an amount of stored oxygen at the three-way catalyst and a three-way catalyst temperature.

7. A method for controlling a regeneration of a particulate filter downstream of an engine, the method comprising:

during a first engine start following a first engine shutdown including an active particulate filter regeneration, combusting with a first air-fuel ratio;

during a second engine start following a second engine shutdown not including an active particulate filter regeneration, combusting with a second air-fuel ratio less rich than the first air-fuel ratio.

8. The method of claim 7, where the active particulate filter regeneration includes increasing excess oxygen to the particulate filter during the first engine shutdown.

9. The method of claim 8, where active particulate filter regeneration further includes controlling a particulate filter temperature within a selected temperature range, and controlling excess oxygen at the particulate filter within a selected excess oxygen range.

10. The method of claim 7, where the first air-fuel ratio and the second air-fuel ratio are based on an amount of oxygen stored at a three-way catalyst positioned downstream of the engine.

11. The method of claim 7, where following includes immediately following, such that there is not an engine start between the first engine shutdown and the first engine start and such that there is not an engine start between the second engine shutdown and the second engine start.

12. A method for controlling regeneration of a particulate filter downstream of a direct-injection, spark-ignition engine, the method comprising:

during a first engine shutdown, increasing excess oxygen to a particulate filter positioned downstream of a three-way catalyst, to regenerate the particulate filter;

during a first start following the first engine shutdown, operating an engine with a first air-fuel ratio;

during a second engine shutdown, reducing excess oxygen to the particulate filter; and

during a second start following the second engine shutdown, operating an engine with a second air-fuel ratio that is less rich than the first air-fuel ratio.

13. The method of claim 12, where following includes immediately following, such that there is not an engine start between the first engine shutdown and the first start and such that there is not an engine start between the second engine shutdown and the second start.

14. The method of claim 12, where the increasing of excess oxygen includes increasing a throttle opening, and where the reducing of excess oxygen includes decreasing the throttle opening.

15. The method of claim 14, where the increasing of excess oxygen includes positioning an intake valve of a cylinder and an exhaust valve of the cylinder to be open such that air flows through the cylinder to the particulate filter during the first engine shutdown.

16. The method of claim 14, where the increasing of excess oxygen includes closing a plurality of cylinders of the engine, and opening an HP EGR valve during the first engine shutdown so that air flows through an HP EGR conduit to the particulate filter during the first engine shutdown.

17. The method of claim 12, where increasing excess oxygen to the particulate filter during the first engine shutdown includes setting an air-fuel ratio to be lean for one or more last combustions.

18. The method of claim 12, where decreasing excess oxygen to the particulate filter during the second engine shutdown includes setting an air-fuel ratio to be about-stoichiometric for one or more last combustions.

19. The method of claim 12, further comprising, during the first engine start, adjusting the air-fuel ratio, spark timing, injection timing, and/or throttle opening based on an amount of oxygen stored at the three-way catalyst.