Engine torque smoothing
First Claim
1. A method of estimating a torque profile of an engine having a plurality of working chambers during operation of the engine, the engine being arranged to operate in a sequence of firing opportunities, each firing opportunity having a corresponding working cycle having a corresponding operational state, each operational state having an associated normalized torque profile, the method comprising:
- determining or selecting a normalized torque profile corresponding to an operational state of a selected working chamber during a selected working cycle;
determining a torque profile for the selected working chamber based at least in part on scaling the normalized torque profile corresponding to the selected working chamber'"'"'s operational state, wherein the scaling varies as a function of one or more current engine operating parameters; and
summing torques profiles for all of the engine'"'"'s working chambers to obtain an estimated overall engine torque profile, the summed torque profiles including the torque profile for the selected working chamber.
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Accused Products
Abstract
Methods, devices, estimators, controllers and algorithms are described for estimating the torque profile of an engine and/or for controlling torque applied to a powertrain by one or more devices other than the engine itself to manage the net torque applied by the engine and other device(s) in manners that reduce undesirable NVH. The described approaches are particularly well suitable for use in hybrid vehicles in which the engine is operated in a skip fire or other dynamic firing level modulation manner—however they may be used in a variety of other circumstances as well. In some embodiments, the hybrid vehicle includes a motor/generator that applies the smoothing torque.
128 Citations
28 Claims
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1. A method of estimating a torque profile of an engine having a plurality of working chambers during operation of the engine, the engine being arranged to operate in a sequence of firing opportunities, each firing opportunity having a corresponding working cycle having a corresponding operational state, each operational state having an associated normalized torque profile, the method comprising:
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determining or selecting a normalized torque profile corresponding to an operational state of a selected working chamber during a selected working cycle; determining a torque profile for the selected working chamber based at least in part on scaling the normalized torque profile corresponding to the selected working chamber'"'"'s operational state, wherein the scaling varies as a function of one or more current engine operating parameters; and summing torques profiles for all of the engine'"'"'s working chambers to obtain an estimated overall engine torque profile, the summed torque profiles including the torque profile for the selected working chamber. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 28)
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21. A method of estimating a torque profile versus crank angle of a dynamic firing level modulation controlled internal combustion engine comprising:
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for each cylinder of the engine, determining a normalized torque profile versus crank angle for each stroke of a piston reciprocating in the cylinder, wherein the normalized torque profile is based on intake manifold pressure; scaling the normalized torque profile to determine the cylinder torque; and summing the cylinder torques for all cylinders in the engine to obtain an overall engine torque profile. - View Dependent Claims (22, 23, 24, 25, 26)
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27. A method of reducing vibration produced by an internal combustion engine using a model of torque produced by the engine, the method comprising:
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determining a predicted engine torque profile for a fire/skip decision made but not yet implemented based on the model; filtering the predicted torque profile to generate a filtered predicted torque signal; setting a gain block based on one or more engine parameters; adding a time delay to the filtered predicted torque signal so that a timing of the filtered predicted torque signal aligns with a timing of an expected output of the engine corresponding to the fire/skip decision; inverting the filtered predicted torque signal; and controlling an electric motor/generator to source/sink torque based on the inverted torque signal.
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Specification