FIRING FRACTION MANAGEMENT IN SKIP FIRE ENGINE CONTROL
First Claim
Patent Images
1. A skip fire engine controller comprising:
- a firing fraction determining unit arranged to determine a firing fraction suitable for delivering a desired engine output, wherein the firing fraction determining unit is arranged to determine an operational firing fraction that has an associated repeating firing cycle length that will repeat at least a designated number of times per second at the current engine speed; and
a firing controller arranged to direct firings in a skip fire manner that delivers the operational firing fraction.
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Abstract
In various described embodiments skip fire control is used to deliver a desired engine output. A controller determines a skip fire firing fraction and (as appropriate) associated engine settings that are suitable for delivering a requested output. In one aspect, the skip fire controller is arranged to select a base firing fraction that has a repeating firing cycle length that will repeat at least a designated number of times per second at the current engine speed. Such an arrangement can be helpful in reducing the occurrence of undesirable vibrations.
83 Citations
36 Claims
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1. A skip fire engine controller comprising:
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a firing fraction determining unit arranged to determine a firing fraction suitable for delivering a desired engine output, wherein the firing fraction determining unit is arranged to determine an operational firing fraction that has an associated repeating firing cycle length that will repeat at least a designated number of times per second at the current engine speed; and a firing controller arranged to direct firings in a skip fire manner that delivers the operational firing fraction. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A skip fire engine controller comprising:
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a requested firing fraction calculator arranged to determine a requested firing fraction suitable for delivering a desired engine output under selected engine operating conditions; an adjusted firing fraction determining unit arranged to determine an operational firing fraction that reduces vibrations within a defined frequency range relative to the requested firing fraction; and a firing controller arranged to direct firings in a skip fire manner that delivers the operational firing fraction. - View Dependent Claims (18, 19)
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20. A skip fire engine controller comprising:
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a firing fraction determining unit arranged to determine an operational skip fire firing fraction suitable for delivering a desired engine output; a firing controller arranged to direct firings in a skip fire manner that delivers the determined operational firing fraction; and wherein the firing fraction determining unit is arranged to only select firing fractions that do not result in the firing controller directing firings in firing patterns having frequency components below a designated frequency threshold.
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21. A skip fire engine controller comprising:
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a firing fraction determining unit arranged to receive an input signal indicative of a desired engine output and to determine an operational firing fraction suitable for delivering the desired engine output, wherein the firing fraction determining unit is arranged to determine a maximum firing cycle length which can be used at a current engine speed while insuring that a firing cycle will repeat at a rate at or above a designated minimum frequency at the current engine speed, and the determined operational firing fraction is associated with a firing pattern having a repeating cycle length that does not exceed the determined maximum firing cycle length, whereby the number of possible firing fractions vary as a function of engine speed; and a firing controller arranged to direct firings in a skip fire manner that delivers the operational firing fraction.
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- 22. A skip fire engine controller comprising a vibration control unit that receives a signal indicative of a requested firing fraction associated with a desired engine output and determines whether the requested firing fraction includes undesirable frequency components, wherein when the vibration control unit determines that the requested firing fraction signal has undesirable frequency components, the vibration control unit determines a modified desired firing fraction and adjusts selected engine control parameters sufficiently such that the engine outputs the desired output at the modified firing fraction.
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24. A skip fire engine controller comprising:
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a requested firing fraction determining unit arranged to receive an input signal indicative of a desired engine output and to determine a firing fraction suitable for delivering the desired engine output under selected engine operating conditions, wherein the firing fraction determining unit outputs a requested firing fraction signal indicative of a desired firing fraction; a vibration control unit that determines whether the desired firing fraction would cause the generation of a firing sequence that includes undesirable frequency components, wherein when the vibration control unit determines that the requested firing fraction signal would cause the generation of a firing sequence that has undesirable frequency components, the vibration control unit determines a modified firing fraction that would cause substantially less of the undesirable frequency components than the requested firing fractions and causes the adjustment of selected engine control parameters sufficiently such that the engine outputs the desired output at the modified firing fraction; and a firing controller arranged to direct firings in a skip fire manner that delivers the modified firing fraction. - View Dependent Claims (25)
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26. A method of controlling the operation of an internal combustion engine having at least one working chamber, the method comprising:
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determining an operational firing fraction and associated engine settings suitable for delivering a desired engine output, wherein the determined operational firing fraction has an associated repeating firing cycle length that will repeat at least a designated number of times per second at the current engine speed; and directing firings of the at least one working chamber in a skip fire manner that delivers the determined firing fraction. - View Dependent Claims (30, 32, 33, 34, 35, 36)
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27. A method of controlling the operation of an internal combustion engine having at least one working chamber, the method comprising:
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determining a requested firing fraction suitable for delivering a desired engine output under selected engine operating conditions; and determining an operational firing fraction that reduces vibrations within a defined frequency range relative to the requested firing fraction; and directing firings in a skip fire manner that delivers the operational firing fraction. - View Dependent Claims (28)
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29. A method of determining a firing fraction for use by a skip fire engine controller arrange to direct engine working chamber firings in a skip fire manner to deliver a desired engine output, the method comprising:
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determining a maximum firing cycle length which can be used at a current engine speed while insuring that a firing cycle will repeat at least at a designated minimum frequency at the current engine speed; and selecting an operational firing fraction associated with a firing pattern having a repeating cycle length that does not exceed the determined maximum firing cycle length, whereby the number of possible firing fractions vary as a function of engine speed. - View Dependent Claims (31)
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Specification