LOOK-UP TABLE BASED SKIP FIRE ENGINE CONTROL
First Claim
1. A skip fire engine controller comprising:
- a look-up table embodied in a computer readable media, the look-up table having a multiplicity of entries and wherein at least some of the entries include a first element that indicates a firing decision and a second element that includes indexing information that is at least sometimes used to determine a relevant lookup table entry for a next firing decision; and
a firing controller arranged to direct firings in a skip fire manner that delivers a desired engine output, wherein the firing controller utilizes the look-up table to determine when firing are appropriate.
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Accused Products
Abstract
A variety of skip fire engine controllers and control methods are described that utilize look-up tables, state machines, or other data structures to determine the sequence or ordering of skip-fire firings. In one aspect, a skip fire engine controller utilizes a look-up table to determine when firings are appropriate to deliver a desired engine output. In some embodiments, a firing timing controller tracks a value indicative of the portion of a firing that has been requested, but not yet directed and such information is utilized in the determination of the timing of the firings. The accumulator value is particularly useful when transitioning between different requested firing fractions.
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Citations
29 Claims
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1. A skip fire engine controller comprising:
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a look-up table embodied in a computer readable media, the look-up table having a multiplicity of entries and wherein at least some of the entries include a first element that indicates a firing decision and a second element that includes indexing information that is at least sometimes used to determine a relevant lookup table entry for a next firing decision; and a firing controller arranged to direct firings in a skip fire manner that delivers a desired engine output, wherein the firing controller utilizes the look-up table to determine when firing are appropriate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A skip fire engine controller comprising:
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a firing fraction determining unit arranged to determine a desired operating firing fraction; a look-up table having a multiplicity of entries and wherein indices for the look-up table include desired firing fraction and a current accumulator value, each entry including;
(i) a firing indicator field arranged to store an associated firing indicator that indicates whether to fire or to skip a working cycle; and
(ii) an accumulator value field arranged to store an associated accumulator value indicative of a portion of a firing that has been requested, but not directed; anda firing controller arranged to direct firings in a skip fire manner that delivers the desired firing fraction, wherein the firing controller utilizes the look-up table to determine when firings are appropriate, the firing controller being arranged to use a current firing fraction request and an accumulator value associated with a prior firing decision as indices for the lookup table to facilitate making the next firing decision. - View Dependent Claims (16, 17)
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18. A method of controlling a skip fire engine in accordance with a predetermined control algorithm, wherein the control algorithm is implemented at least in part using a lookup table having a multiplicity of entries and wherein each entry includes a first element that indicates a firing decision and a second element that includes indexing information that is at least sometimes used to determine a relevant lookup table entry for a next firing decision.
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19. A method of determining firings during operation of an engine in a skip fire operational mode, the method comprising:
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determining a desired firing fraction; and accessing a multi-dimensional lookup table to determine specific firings, wherein the desired firing fraction is utilized as a first index for the lookup table and wherein a second index is used for accessing the lookup table at least when changing between desired firing fractions. - View Dependent Claims (20, 21)
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- 22. A skip fire engine controller arranged to direct firings in a skip fire manner that delivers a desired engine output, wherein the skip fire engine controller utilizes a state machine to determine when firings are appropriate to deliver the desired engine output.
- 27. A method of controlling a skip fire engine wherein the sequence of the skip fire firings is determined through the use of a state machine.
Specification