Noise, vibration and harshness reduction in a skip fire engine control system
First Claim
1. A powertrain controller for directing operation of an internal combustion engine having a plurality of cylinders, each cylinder being arranged to operate in a sequence of working cycles, each working cycle having an associated firing opportunity, the internal combustion engine having an associated engine cycle that constitutes one firing opportunity for each cylinder, the powertrain controller comprising:
- a firing controller arranged to direct firings in a sequence of cylinder working cycles, wherein selected first working cycles are directed to have a greater torque output than selected second working cycles within the same engine cycle, the first and second working cycles being interspersed; and
an NVH reduction module that is configured to (a) determine a smoothing torque to be applied to a powertrain by an energy storage/release device, the determination of the smoothing torque being affirmatively made during operation of the engine, and (b) direct the energy storage/release device to apply the smoothing torque to the powertrain, wherein the smoothing torque is arranged to at least partially cancel out a variation in torque output generated by the first and second working cycles, and (c) select a magnitude of the smoothing torque based on fuel efficiency and further based on whether the smoothing torque brings NVH generated by the operation of the engine below a predefined NVH target level.
1 Assignment
0 Petitions
Accused Products
Abstract
A variety of methods and arrangements for reducing noise, vibration and harshness (NVH) in a skip fire engine control system are described. In one aspect, a firing sequence is used to operate the engine in a skip fire manner. A smoothing torque is determined that is applied to a powertrain by an energy storage/release device. The smoothing torque is arranged to at least partially cancel out variation in torque generated by the skip fire firing sequence. Various methods, powertrain controllers, arrangements and computer software related to the above operations are also described.
-
Citations
15 Claims
-
1. A powertrain controller for directing operation of an internal combustion engine having a plurality of cylinders, each cylinder being arranged to operate in a sequence of working cycles, each working cycle having an associated firing opportunity, the internal combustion engine having an associated engine cycle that constitutes one firing opportunity for each cylinder, the powertrain controller comprising:
-
a firing controller arranged to direct firings in a sequence of cylinder working cycles, wherein selected first working cycles are directed to have a greater torque output than selected second working cycles within the same engine cycle, the first and second working cycles being interspersed; and an NVH reduction module that is configured to (a) determine a smoothing torque to be applied to a powertrain by an energy storage/release device, the determination of the smoothing torque being affirmatively made during operation of the engine, and (b) direct the energy storage/release device to apply the smoothing torque to the powertrain, wherein the smoothing torque is arranged to at least partially cancel out a variation in torque output generated by the first and second working cycles, and (c) select a magnitude of the smoothing torque based on fuel efficiency and further based on whether the smoothing torque brings NVH generated by the operation of the engine below a predefined NVH target level. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A powertrain controller for directing operation of an internal combustion engine having a plurality of cylinders, each cylinder being arranged to operate in a sequence of working cycles, each working cycle having an associated firing opportunity, the internal combustion engine having an associated engine cycle that constitutes one firing opportunity for each cylinder, the powertrain controller comprising:
-
a firing controller arranged to direct firings in a sequence of cylinder working cycles, wherein selected first working cycles are directed to have a greater torque output than selected second working cycles within the same engine cycle, the first and second working cycles being interspersed; and an NVH reduction module that is configured to (a) determine a smoothing torque to be applied to a powertrain by an energy storage/release device, the determination of the smoothing torque being affirmatively made during operation of the engine, and (b) direct the energy storage/release device to apply the smoothing torque to the powertrain, wherein the smoothing torque is arranged to at least partially cancel out a variation in torque output generated by the first and second working cycles; and a firing fraction calculator, and wherein the firing fraction calculator and the NVH reduction module are arranged to; select the operational firing fraction from a set of available firing fractions that includes a first firing fraction that is associated with unacceptable NVH levels and a second firing fraction that is associated with acceptable NVH levels; and determine energy costs associated with mitigating the NVH levels associated with the first firing fraction, the mitigating of the NVH levels involving applying the smoothing torque to the powertrain to help reduce the NVH levels associated with the first firing fraction wherein the selection of the operational firing fraction is based at least in part on the energy costs determination. - View Dependent Claims (9)
-
-
10. A powertrain controller for directing operation of an internal combustion engine having a plurality of cylinders, each cylinder being arranged to operate in a sequence of working cycles, each working cycle having an associated firing opportunity, the internal combustion engine having an associated engine cycle that constitutes one firing opportunity for each cylinder, the powertrain controller comprising:
-
a firing controller arranged to direct firings in a sequence of cylinder working cycles, wherein selected first working cycles are directed to have a greater torque output than selected second working cycles within the same engine cycle, the first and second working cycles being interspersed; and an NVH reduction module that is configured to (a) determine a smoothing torque to be applied to a powertrain by an energy storage/release device, the determination of the smoothing torque being affirmatively made during operation of the engine based on adaptive feed forward control, and (b) direct the energy storage/release device to apply the smoothing torque to the powertrain, wherein the smoothing torque is arranged to at least partially cancel out a variation in torque output generated by the first and second working cycles.
-
-
11. A method of operating an internal combustion engine having a plurality of cylinders, each cylinder being arranged to operate in a sequence of working cycles, each working cycle having an associated firing opportunity, the internal combustion engine being part of a powertrain and having an associated engine cycle that constitutes one firing opportunity for each cylinder, the method comprising:
-
obtaining a set of available firing fractions that can deliver the desired torque; determining a first subset of one or more of the available firing fractions that have acceptable NVH levels; determining a second subset of one or more of the available firing fractions that have unacceptable NVH levels; and determining an energy cost associated with NVH mitigation required to reduce NVH levels for each firing fraction in the second subset to acceptable levels wherein the NVH mitigation involves determining a smoothing torque arranged to at least partially cancel out variations in the torque generated by use of such firing fraction; selecting an operational firing fraction from one of the first and second subsets of available firing fractions and directing operation of a sequence of cylinder working cycles to deliver the operational firing fraction, wherein selected first working cycles are directed to have a greater torque output than selected second working cycles within the same engine cycle, the first and second working cycles being interspersed; and when the selected operational firing fraction is in the second subset, supplying the associated smoothing torque to the powertrain to reduce vibration generated by the firing sequence. - View Dependent Claims (12, 13, 14, 15)
-
Specification