Drive train slip for vibration mitigation during skip fire operation
First Claim
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1. A method of mitigating power train vibration during skip fire operation of an engine, the method comprising:
- operating an engine in a skip fire operational mode; and
for each firing opportunity in a sequence of firing opportunities that occur during the skip fire operation of the engine, determining a drive train component slip dynamically on an individual firing opportunity by firing opportunity basis, wherein the slip of the drive train component associated with each firing opportunity is based at least in part upon a skip/fire decision associated with such firing opportunity; and
modulating the slip of the drive train component in accordance with the determined drive train component slip, whereby in at least some circumstances, the slip of the drive train will be adjusted both up and down for different firing opportunities within a single engine cycle while operating in the skip fire mode.
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Abstract
A variety of methods and devices for mitigating power train vibration during skip fire operation of an engine are described. In one aspect, the slip of a drive train component (such as a torque converter clutch) is based at least in part upon a skip fire characteristic (such as firing fraction, selected firing sequence/pattern, etc.) during skip fire operation of an engine. The modulation of the drive train component slip can also be varied as a function of one or more engine operating parameters such as engine speed and/or a parameter indicative of the output of fired cylinders (such as mass air charge).
77 Citations
27 Claims
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1. A method of mitigating power train vibration during skip fire operation of an engine, the method comprising:
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operating an engine in a skip fire operational mode; and for each firing opportunity in a sequence of firing opportunities that occur during the skip fire operation of the engine, determining a drive train component slip dynamically on an individual firing opportunity by firing opportunity basis, wherein the slip of the drive train component associated with each firing opportunity is based at least in part upon a skip/fire decision associated with such firing opportunity; and modulating the slip of the drive train component in accordance with the determined drive train component slip, whereby in at least some circumstances, the slip of the drive train will be adjusted both up and down for different firing opportunities within a single engine cycle while operating in the skip fire mode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of mitigating vibration during skip fire operation of an engine in a vehicle having a power train that includes a torque converter clutch, the method comprising:
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operating an engine in a skip fire operational mode; and modulating slip of a torque converter clutch (TCC) based at least in part upon selected skip/fire decisions associated with particular firing opportunities, wherein relatively higher TCC slip values are used any time a firing is commanded that follows a skip and relatively lower TCC slip values are used any time a skip is commanded. - View Dependent Claims (12, 13, 14)
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15. A powertrain controller comprising:
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a firing controller configured to at least sometimes direct an engine to operate in a skip fire operational mode; and a power train component controller arranged to control the slip of a power train component based at least in part upon one or more individual skip/fire decisions, wherein during selected skip fire operation, the power train component controller is arranged to determine the slip of the drive train component dynamically on an individual firing opportunity by firing opportunity basis, and to command relatively higher TCC slip values any time a firing is commanded that follows a skip and relatively lower TCC slip values any time a skip is commanded. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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23. A vehicle powertrain comprising:
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an engine; an engine controller arranged to operate the engine in a skip fire operational mode; a transmission; and a torque converter clutch; and a torque converter clutch control block arranged to modulate the slip of the torque converter clutch as a function of a set of skip/fire decisions including the selected skip/fire decision and one or more preceding skip/fire decisions corresponding to a set of firing opportunities immediately preceding the particular firing opportunity. - View Dependent Claims (24, 25, 26, 27)
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Specification