Noise/vibration control using variable spring absorber
First Claim
1. A method of mitigating vibration in a vehicle having a powertrain that includes an engine and a variable spring absorber, the engine including a plurality of working chambers, the method comprising:
- operating the engine in a cylinder output level modulation mode at a first effective firing fraction, wherein operation of the engine at the first effective firing fraction causes the working chambers to be fired in a repeating firing sequence having a defined minimum repeating pattern length; and
tuning an absorption frequency of the variable spring absorber for use during operation of the engine at the first effective firing fraction based at least in part on a current engine speed and a factor indicative of the minimum repeating pattern length associated with the first effective firing fraction.
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Abstract
Systems and methods are described for mitigating vehicle vibration through the control of a variable spring absorber that is part of a powertrain that includes the engine. In some such embodiments, an absorption frequency of the variable spring absorber is tuned in a feed forward manner based at least in part on the current engine speed and a factor indicative of the minimum repeating firing sequence cycle length associated with the current effective firing fraction (which in many implementations may be the denominator of the firing fraction).
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Citations
16 Claims
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1. A method of mitigating vibration in a vehicle having a powertrain that includes an engine and a variable spring absorber, the engine including a plurality of working chambers, the method comprising:
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operating the engine in a cylinder output level modulation mode at a first effective firing fraction, wherein operation of the engine at the first effective firing fraction causes the working chambers to be fired in a repeating firing sequence having a defined minimum repeating pattern length; and tuning an absorption frequency of the variable spring absorber for use during operation of the engine at the first effective firing fraction based at least in part on a current engine speed and a factor indicative of the minimum repeating pattern length associated with the first effective firing fraction. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for reducing at least one of noise and vibration generated by an internal combustion engine during operation of the engine, the system comprising:
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a powertrain that includes the engine and a variable spring absorber; an engine controller configured to direct operation of the engine in a cylinder output level modulation mode; and an absorber controller arranged to set an absorption frequency for the variable spring absorber during cylinder output level modulation operation of the engine, wherein the absorption frequency is set based at least in part on a minimum repeating pattern length of a repeating firing sequence associated with an operational firing fraction and level fraction. - View Dependent Claims (11, 12, 13, 15, 16)
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14. The system as recited in 10 wherein the engine controller is further configured to direct operation of the engine in a skip fire operational mode, and for each firing opportunity, an independent firing decision is made whether to skip or fire an individual associated working chamber during such firing opportunity.
Specification