Engine torque smoothing

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.

1 . A control system configured to control the transition of an engine between different displacements in a hybrid vehicle having an internal combustion engine and an additional power source/sink, the control system comprising:
 an engine control unit configured to direct operation of the engine, including directing the transition of the engine from a first operational displacement to a second operational displacement that is different than the first operational displacement;   a torque profile estimator configured to determine an engine torque profile associated with the transition from the first operational displacement to the second operational displacement; and   an additional power source/sink controller configured to determine a smoothing torque based at least in part of the determined engine torque profile and to direct the additional power source/sink to apply the smoothing torque during the transition from the first operational firing fraction.