Motor torque smoothing on combustion engines by approximating a periodic waveform using sinusoids

A method for managing motor torque smoothing for internal combustion engine cylinder skipping and recharging events, the method comprising:

• operating the internal combustion engine at a first firing fraction that is less than a value of 1.0, wherein one or more cylinders are not designated to be fired and one or more cylinders are designated to be fired;
• determining a smoothing event time period where each of the cylinders that have not been designated to be fired are either skipped or recharged during operation of the engine, including firing of the cylinders designated for firing;
• select a periodic disruptive waveform to approximate that is related to a skip or recharge event that is part of the smoothing event time period;
• determine a timeframe for utilizing the first harmonic;
• and
• initiating actuation of an additional power source to supply a supplemental quantity of torque during the smoothing event time period based on the approximated waveform.

An engine control system in a vehicle for managing motor torque smoothing for internal combustion engine cylinder skipping and recharging events, the system comprising:

• an internal combustion engine that provides power to a drivetrain of a vehicle;
• an additional power source that provides supplemental power to the drivetrain;
• and
• an engine controller configured to:
• operate the internal combustion engine at a first firing fraction that is less than a value of 1.0, wherein one or more cylinders are not designated to be fired;
• determine a smoothing event time period where each of the cylinders that have not been designated to be fired are either skipped or recharged during operation of the engine, wherein operation of the engine includes firing of the cylinders designated for firing;
• select a periodic disruptive waveform to approximate that is related to a skip or recharge event that is part of the smoothing event time period;
• determine a first harmonic sinusoid from a group of harmonic sinusoids that reduces the error between an approximated waveform and the disruptive waveform;
• determine a timeframe for utilizing the first harmonic;
• and
• initiate actuation of an additional power source to supply a supplemental quantity of torque during the smoothing event time period based on the approximated waveform.