Managing firing phase transitions

• US 10,393,085 B2
• Filed: 12/04/2017
• Issued: 08/27/2019
• Est. Priority Date: 10/20/2016
• Status: Active Grant

• Current Assignee: Tula Technology, Incorporated
• Original Assignee: Tula Technology, Incorporated
• Inventors: Serrano, Louis J.
• Primary Examiner(s): Steckbauer, Kevin R
• Application Number:
  US15/830,388
• Publication Number:
  US 20180112644A1
• Time in Patent Office: 631 Days
• CPC Class Codes: F02D 13/06 Cutting-out cylinders
• CPC Class Codes: F02D 17/00 Controlling engines by cutting out individual cylinders; Rendering engines inoperative or idling controlling or rendering inoperative by varying inlet or exhaust valve operating characteristics F02D13/00
• CPC Class Codes: F02D 17/02 Cutting-out cutting-out engines in multiple engine arrangements F02D25/04
• CPC Class Codes: F02D 2041/0012 with selective deactivation of cylinders
• CPC Class Codes: F02D 2041/286 comprising means for signal processing
• CPC Class Codes: F02D 2250/18 Control of the engine output torque
• CPC Class Codes: F02D 2250/21 during a transition between engine operation modes or states
• CPC Class Codes: F02D 41/0085 Balancing of cylinder outputs, e.g. speed, torque or air-fuel ratio
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/3058 the engine working with a variable number of cycles
• CPC Class Codes: F02P 5/1502 using one central computing unit
• CPC Class Codes: F02P 9/002 Control of spark intensity, intensifying, lengthening, suppression by means of current control in the storage devices F02P3/05, F02P3/09, during starting F02P15/12

Abstract

Methods and controllers for dynamically altering the phase of a firing sequence during operation of an engine are described. The described methods and controllers are particularly useful in conjunction with cylinder output level modulation operation of an engine such as dynamic skip fire operation of the engine and/or multi-charge level operation of the engine.

Claims

1. An engine controller configured to direct operation of an engine having a plurality of working chambers at a first effective firing fraction that is less than one, the engine controller being configured to:

(a) determine whether a selected working chamber firing decision is consistent with a firing decision that would be made when a firing sequence associated with the first effective firing fraction is in a desired phase; and

(b) when it is determined that the selected working chamber firing decision is not consistent with the firing decision that would be made when the firing sequence is in the desired phase, at least sometimes, adjusting the phase of the firing sequence; and

(c) repeating steps (a) and (b) as necessary at least until the desired phase is attained, wherein steps (a) and (b) are performed by a first order sigma delta converter during operation of the engine at the first effective firing fraction; and

whereby the phase of the firing sequence is altered from a first phase to the desired phase while the engine continues to operate at the first effective firing fraction by adding an offset value to an accumulator in the sigma delta converter.

2. An engine controller as recited in claim 1 wherein an absolute value of the offset value is a fraction equal to the reciprocal of the denominator of the first effective firing fraction.

3. An engine controller as recited in claim 1 wherein an absolute value of the offset value is a value less than the reciprocal of the denominator of the first effective firing fraction.

4. An engine controller as recited in claim 1 wherein an absolute value of the offset value is a reciprocal of a number of working chambers that the engine has.

5. An engine controller as recited in claim 1 wherein the working chambers have a set firing opportunity order and firing sequence phase adjustments are not made during any working cycle that immediately follows a fired working cycle in the preceding working chamber in the working chamber firing opportunity order.

6. An engine controller as recited in claim 1 wherein firing sequence phase adjustments are not made during any working cycle that immediately follows a working cycle in which a firing sequence phase adjustment was made.

7. An engine controller as recited in claim 2 wherein the firing sequence phase adjustment is accomplished by running one or more phantom cycles of the sigma delta converter.

8. An engine controller as recited in claim 1 wherein the offset value is a negative value.

9. An engine controller as recited in claim 1 wherein the firing sequence associated with the first effective firing fraction skips selected firing opportunities.

10. An engine controller as recited in claim 1 wherein the firing sequence associated with the first effective firing fraction is a multi-charge level firing sequence.

11. An engine controller configured to direct operation of an engine having a plurality of working chambers, the engine controller being configured to:

direct operation of the engine in a cylinder output level modulation mode at a first effective firing fraction, wherein cylinder output level determinations are made using a first order sigma delta converter during operation of the engine in the cylinder output level modulation mode at the first effective firing fraction;

transition the engine to operate at a second effective firing fraction that has a corresponding second firing sequence that repeats each engine cycle, wherein the second firing fraction is entered at a first phase; and

alter the phase of the second firing sequence to a desired second phase to thereby cause at least some of the working chambers to have a different output level than if the engine were to continue operating using the first phase of the second effective firing fraction, wherein altering the phase of the second firing sequence to the desired second phase while the engine continues to operate at the second effective firing fraction is accomplished by adding an offset value to an accumulator in the sigma delta converter.

12. An engine controller as recited in claim 11 wherein the first effective firing fraction has an ergodic firing sequence.

13. An engine controller as recited in claim 11 wherein the second firing fraction is a simple fraction having a denominator that is a factor of the number of working chambers that the engine has.

14. An engine controller as recited in claim 11 wherein:

the first order sigma delta converter includes an accumulator that tracks the portion of a firing that has been requested but not delivered, or delivered but not requested; and

the phase of the second firing sequence is altered by adding an offset value to the accumulator.

15. An engine controller as recited in claim 11 wherein the phase of the second firing sequence is altered by running at least one phantom cycle of the sigma delta converter to thereby cause the generation of a firing decision output that does not influence the firing decision associated with any working chamber working cycle.

16. An engine controller as recited in claim 15 comprising running a plurality of the phantom cycles of the sigma delta converter, wherein the plurality of phantom cycles of the sigma delta conversion immediately follow one another until a desired phase for the second firing sequence is attained.

17. An engine controller as recited in claim 14 wherein an absolute value of the offset value is a fraction that is the reciprocal the denominator of the second firing fraction.

18. An engine controller as recited in claim 14 wherein an absolute value of the offset value is less than the fraction that is the reciprocal the denominator of the second firing fraction.

19. An engine controller as recited in claim 16 further comprising, after operation at the second firing fraction at the altered phase, transitioning to a third firing fraction that is different that the second firing fraction;

and wherein no offset values are added to or subtracted from the accumulator in conjunction with the transition to the third firing fraction.

20. An engine controller as recited in claim 11 wherein the second firing sequence skips selected firing opportunities.

21. An engine controller as recited in claim 11 wherein the second firing sequence is a multi-charge level firing sequence.

22. A method of operating an engine having a plurality of working chambers, the method comprising:

operating an engine in a cylinder output level modulation mode at a first effective firing fraction, wherein cylinder output level determinations are made using a first order sigma delta converter during operation of the engine in the cylinder output level modulation mode at the first effective firing fraction;

transitioning to operating the engine at a second effective firing fraction that has a corresponding second firing sequence that repeats each engine cycle, wherein the second firing fraction is entered at a first phase; and

altering the phase of the second firing sequence to a desired second phase to thereby cause at least some of the working chambers to have a different output level than if the engine were to continue operating using the first phase of the second effective firing fraction, wherein altering the phase of the second firing sequence to the desired second phase while the engine continues to operate at the second effective firing fraction is accomplished by adding an offset value accumulator in the sigma delta converter.

23. A method of altering the phase of a firing sequence during operation of an engine having a plurality of working chambers in a cylinder output level modulation mode at a first effective firing fraction that is less than one, the method comprising:

(a) determining whether a selected working chamber firing decision is consistent with a firing decision that would be made when the firing sequence is in a desired phase; and

(b) when it is determined that the selected working chamber firing decision is not consistent with the firing decision that would be made when the firing sequence is in the desired phase, at least sometimes, adjusting the phase of the firing sequence; and

(c) repeating steps (a) and (b) as necessary at least until the desired phase is attained, wherein steps (a) and (b) are performed by a first order sigma delta converter during operation of the engine at the first effective firing fraction; and

whereby the phase of the firing sequence is altered from a first phase to the desired phase while the engine continues to operate at the first effective firing fraction by adding an offset value to an accumulator in the sigma delta converter.