Managing engine firing patterns and pattern transitions during skip fire engine operation
First Claim
1. A method of managing a transition between a first operational firing fraction and a second operational firing fraction during operation of an engine in a skip fire operational mode, the first firing fraction having an associated first repeating firing sequence and the second firing fraction having an associated second repeating firing sequence, the method comprising:
- identifying a firing sequence segment of a designated length that is shared by the first and second firing fractions, wherein the shared firing sequence segment is a set of individual working chamber firing decisions that is the same in the first and second repeating firing sequences, the first and second firing fractions being different; and
transitioning from the first to the second firing fraction in conjunction with the execution of the shared firing sequence segment, whereby the firing fraction entering the shared firing sequence is the first firing fraction and the firing fraction exiting the shared sequence is the second firing fraction.
1 Assignment
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Accused Products
Abstract
Various methods and data structures for managing transition between different firing fractions during skip fire operation of an engine are described. In some embodiments, transitions are constrained to occur when firing sequence segments of a designated length are shared by the first and second firing fractions. In a separate aspect, a data structure that uses current firing fraction phase as a first index and a target firing fraction as a second index may be used to determine a phase of the target firing fraction to enter at a transition. Is some circumstances transitions between a current and target firing fraction may be conducted as a series of steps through intermediate firing fractions.
87 Citations
21 Claims
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1. A method of managing a transition between a first operational firing fraction and a second operational firing fraction during operation of an engine in a skip fire operational mode, the first firing fraction having an associated first repeating firing sequence and the second firing fraction having an associated second repeating firing sequence, the method comprising:
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identifying a firing sequence segment of a designated length that is shared by the first and second firing fractions, wherein the shared firing sequence segment is a set of individual working chamber firing decisions that is the same in the first and second repeating firing sequences, the first and second firing fractions being different; and transitioning from the first to the second firing fraction in conjunction with the execution of the shared firing sequence segment, whereby the firing fraction entering the shared firing sequence is the first firing fraction and the firing fraction exiting the shared sequence is the second firing fraction. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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- 12. A method of managing a transition between a first operational firing sequence representative of a first firing fraction and a second operational firing sequence representative of a second firing fraction during operation of an engine in a skip fire operational mode, the first and second firing fractions being different, the method comprising accessing a data structure using a current firing fraction phase as a first index and a target firing fraction as a second index, to determine a phase of the second firing sequence to enter at the transition.
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18. A method of managing a transition between available firing fractions during operation of an engine in a skip fire mode in which the engine may be operated in any of a multiplicity of available firing fractions, the method comprising:
in response to the reception of a request to change an operational skip fire firing fraction from a first firing fraction to a second firing fraction that is separated from the first firing fraction by at least one intermediate available firing fraction, sequentially transitioning from the first firing fraction to the second firing fraction in a step-wise manner through each intermediate available firing fraction. - View Dependent Claims (19, 20)
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21. A method of managing a transition between a first operational firing fraction and a second operational firing fraction during operation of an engine in a skip fire operational mode, the method comprising:
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transitioning from the first firing fraction to an intermediate firing fraction between the first and second operational firing fractions that is not a normal operational firing fraction; and subsequently transitioning from the intermediate firing fraction to the second firing fraction; and wherein the first and second firing fractions each have an associated firing pattern which includes a fixed set of available firing sequence segments of a designated length of at least four firing decisions; wherein the set of available firing sequence segments for the first and second firing fractions are not coextensive; and wherein the intermediate firing fraction has a set of available firing sequence segments that includes all of the firing sequence segments for the first and second firing fractions.
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Specification