Engine torque smoothing

A method of estimating a torque profile versus crank angle of a dynamic firing level modulation controlled internal combustion engine comprising:

• 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.

A method of reducing vibration produced by an internal combustion engine using a model of torque produced by the engine, the method comprising:

• 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.