Method and system for air charge estimation

• US 9,670,854 B2
• Filed: 10/05/2015
• Issued: 06/06/2017
• Est. Priority Date: 11/20/2014
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Jankovic, Mrdjan J.
• Primary Examiner(s): Kwon, John
• Application Number:
  US14/875,249
• Publication Number:
  US 20160146139A1
• Time in Patent Office: 610 Days
• Field of Search: 701101, 701103, 701110-114, 123564, 123434, 123673, 123679, 123687
• CPC Class Codes: F02B 2075/027 four
• CPC Class Codes: F02B 75/02 Engines characterised by their cycles, e.g. six-stroke
• CPC Class Codes: F02D 13/06 Cutting-out cylinders
• CPC Class Codes: F02D 2041/0012 with selective deactivation of cylinders
• CPC Class Codes: F02D 2200/0402 the parameter being determined by using a model of the engine intake or its components
• CPC Class Codes: F02D 2200/0406 Intake manifold pressure
• CPC Class Codes: F02D 41/0007 for control of turbo-charged or super-charged engines control of the pumps per se F02B37/12
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/18 by measuring intake air flow
• CPC Class Codes: F02D 41/3094 the fuel injection being effected by at least two different injectors, e.g. one in the intake manifold and one in the cylinder
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

Systems and methods are provided. In one example, a method for an engine comprises adjusting an air charge estimate for a first cylinder based on a firing pattern of a second cylinder. In this way, cylinder air charge estimates may be improved in real-time for an arbitrary cylinder firing pattern, thereby improving engine efficiency.

Claims

1. A method for an engine, comprising:

adjusting an air charge estimate for a first cylinder based on an engine firing pattern, including a firing pattern based on firing of a second cylinder.

2. The method of claim 1, further comprising adjusting an engine operating parameter based on the adjusted air charge estimate.

3. The method of claim 2, wherein the engine operating parameter comprises a spark timing.

4. The method of claim 2, wherein the engine operating parameter includes a fuel injection amount.

5. The method of claim 4, further comprising adjusting a ratio of port and direct injection to the first cylinder based on the engine firing pattern.

6. A method for an engine, comprising:

adjusting an air charge estimate for a first cylinder from an engine sensor by a first amount if an immediately following cylinder in an engine cycle fired in its immediately preceding cycle, and by a second amount if the immediately following cylinder is scheduled not to fire in its immediately succeeding cycle; and

adjusting an engine actuator based on the adjusted air charge estimate.

7. The method of claim 6, wherein valves of the first and second cylinders operate with positive valve overlap at top-dead-center of the end of exhaust, wherein the adjusting includes increasing cylinder air charge by the first amount for the first cylinder with a relatively lower exhaust pressure and increased scavenging.

8. The method of claim 7, wherein valves of the first and second cylinders operate with positive valve overlap at top-dead-center of the end of exhaust, wherein the adjusting includes increasing cylinder air charge by the second amount, larger than the first amount for the first cylinder with a relatively higher intake manifold pressure.

9. The method of claim 6, wherein, for each cylinder of the engine cycle, an adjustment to its cylinder air charge is made based on firing or non-firing of the immediately subsequent cylinder in the firing order both in the immediately preceding engine cycle and in the current engine cycle.

10. The method of claim 9, wherein cylinders not firing continue to have intake and exhaust valves operating.

11. A method for an engine, comprising:

adjusting an air charge estimate for a first cylinder by a first amount responsive to a second cylinder not firing during a current cycle and a previous cycle;

adjusting the air charge estimate by a second amount responsive to the second cylinder firing during the current cycle and not firing during the previous cycle;

adjusting the air charge estimate by a third amount responsive to the second cylinder not firing in the current cycle and firing during the previous cycle; and

adjusting fuel injection amounts based on the adjusted air charge estimate.

12. The method of claim 11, further comprising adjusting an engine operating parameter based on the adjusted air charge estimate, wherein the current cycle is a current engine cycle including each cylinder of the engine completing its own cylinder cycle having four strokes, and wherein the previous cycle is a previous engine cycle.

13. The method of claim 11, wherein the second cylinder is an immediately scheduled cylinder following the first cylinder in an engine cycle firing order.

14. The method of claim 13, wherein an engine cycle firing order is the same during both the current cycle and the previous cycle.

15. The method of claim 14, wherein engine fueling is by at least some direct fuel injection into engine cylinders.

16. The method of claim 15, wherein intake air of the engine is boosted by a turbocharger.

17. The method of claim 15, wherein cylinders not firing continue to have intake and exhaust valves operating.

18. The method of claim 17, further comprising adjusting spark timing for each respective cylinder based on its adjusted air charge estimate.

19. The method of claim 18, wherein the air charge is estimated based on one or more of a manifold pressure sensor and a mass air flow sensor during engine operation while the engine is driving wheels of a vehicle along a ground.

20. The method of claim 19, wherein fuel injection to the first cylinder is adjusted directly based on the adjusted cylinder air charge estimate.